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Comparison of carbohydrate content between grain-containing and grain-free dry cat diets and between reported and calculated carbohydrate values

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Objectives The aim of this study was to compare the carbohydrate content of grain-containing and grain-free dry cat diets and compare major protein and carbohydrate sources of these diets. Methods This was a cross-sectional study of 77 randomly selected dry cat diets (42 grain-containing, 35 grain-free). Reported carbohydrate values were compared between grain-containing and grain-free cat diets. A subset of 25% of diets from each category (grain-containing and grain-free) was analyzed and nitrogen-free extract was calculated as an estimate of carbohydrate content. These calculated values were compared with reported values from the manufacturer. Animal- and plant-sourced ingredients were also compared between grain-containing and grain-free diets. Results Mean reported carbohydrate content of the grain-free diets (n = 35) was lower than the grain-containing diets (n = 41; 64 ± 16 vs 86 ± 22 g/1000 kcal; P <0.001). Reported carbohydrate values were higher than analyzed nitrogen-free extract (n = 20; 79 ± 30 vs 73 ± 27 g/1000 kcal; P = 0.024). Poultry ( P = 0.009) and soy (P = 0.007) were less common in grain-free diets than in diets containing grain. The alternative carbohydrate sources of chickpeas, lentils, peas, potato, sweet potato and cassava/tapioca were more common ( P <0.05) in grain-free diets than in diets containing grain. Conclusions and relevance This sample of grain-free diets had lower mean reported carbohydrate content than grain-containing diets, but there was considerable overlap between groups and individual diets’ carbohydrate/nitrogen-free extract content varied widely.
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https://doi.org/10.1177/1098612X17710842
Journal of Feline Medicine and Surgery
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Introduction
The popularity of grain-free pet diets has increased in
recent years. From 2012–2014, the percentage of grain-
free cat food purchased more than doubled, going from
4% to 9% of total cat food purchased.1 Based on our per-
sonal experience, as well as from discussions with other
veterinarians, this percentage has likely continued to
increase since 2014. Reasons for this increase are unknown
but may be related to manufacturers’ marketing efforts
and unsubstantiated consumer beliefs about the role of
grains or carbohydrates in pet foods and the ability of
cats to metabolize carbohydrate. Instead of grains, grain-
free diets typically contain alternate carbohydrate sources
such as white potato, peas and other legumes, sweet
potato or tapioca. It is unclear whether grain-free diets
differ in their total carbohydrate content compared with
grain-containing diets. Information on carbohydrate con-
tent, which is not found on the label, must be obtained
from manufacturers and may be based on total starch,
total sugars or, more commonly, nitrogen-free extract
Comparison of carbohydrate
content between grain-containing
and grain-free dry cat diets and
between reported and calculated
carbohydrate values
Lori R Prantil*, Cailin R Heinze and Lisa M Freeman
Abstract
Objectives The aim of this study was to compare the carbohydrate content of grain-containing and grain-free dry
cat diets and compare major protein and carbohydrate sources of these diets.
Methods This was a cross-sectional study of 77 randomly selected dry cat diets (42 grain-containing, 35 grain-
free). Reported carbohydrate values were compared between grain-containing and grain-free cat diets. A subset
of 25% of diets from each category (grain-containing and grain-free) was analyzed and nitrogen-free extract was
calculated as an estimate of carbohydrate content. These calculated values were compared with reported values
from the manufacturer. Animal- and plant-sourced ingredients were also compared between grain-containing and
grain-free diets.
Results Mean reported carbohydrate content of the grain-free diets (n = 35) was lower than the grain-containing
diets (n = 41; 64 ± 16 vs 86 ± 22 g/1000 kcal; P <0.001). Reported carbohydrate values were higher than
analyzed nitrogen-free extract (n = 20; 79 ± 30 vs 73 ± 27 g/1000 kcal; P = 0.024). Poultry (P = 0.009) and soy
(P= 0.007) were less common in grain-free diets than in diets containing grain. The alternative carbohydrate
sources of chickpeas, lentils, peas, potato, sweet potato and cassava/tapioca were more common (P <0.05) in
grain-free diets than in diets containing grain.
Conclusions and relevance This sample of grain-free diets had lower mean reported carbohydrate content than
grain-containing diets, but there was considerable overlap between groups and individual diets’ carbohydrate/
nitrogen-free extract content varied widely.
Accepted: 27 April 2017
Department of Clinical Sciences, Cummings School of Veterinary
Medicine, Tufts University, North Grafton, MA, USA
* Current address: VCA South Shore Animal Hospital, 595
Columbian Street, South Weymouth, MA 02190, USA
Corresponding author:
Cailin Heinze VMD, MS, DACVN, Department of Clinical Sciences,
Cummings School of Veterinary Medicine, Tufts University, 200
Westboro Road, North Grafton, MA 01536, USA
Email: cailin.heinze@tufts.edu
710842JFM0010.1177/1098612X17710842Journal of Feline Medicine and SurgeryPrantil et al
research-article2017
Original Article
2 Journal of Feline Medicine and Surgery 00(0)
(NFE). NFE is calculated by subtracting the measured per-
cent crude protein, crude fat, crude fiber, moisture and ash
from 100 and assuming the remainder is carbohydrate.
In addition to concerns regarding carbohydrates,
some cat owners have reported to the authors that they
choose grain-free diets because of the perception that
food allergies are common in cats and that grains are a
common allergen. In fact, food allergies are reported to
be uncommon in cats.2 When they do occur, they are
most commonly associated with an animal-source pro-
tein such as beef, chicken, fish or dairy protein rather
than to plant ingredients such as wheat, corn or rice.3,4
Whether grain-free diets contain fewer of the most com-
monly reported food allergens in cats (ie, beef, fish,
chicken or dairy) has not been reported.
To begin to address these issues, the first objective of
this study was to determine whether the manufacturer-
reported carbohydrate content of grain-free dry cat diets
was lower than that of grain-containing diets, with the
hypothesis that there would be no difference in the carbo-
hydrate content between grain-containing and grain-free
diets. Second, since carbohydrate values reported by
manufacturers could encompass a number of different
types of assays and methods, reported carbohydrate val-
ues were compared with calculated NFE in a subset of
grain-free and grain-containing cat diets. Our hypothesis
was that there would be no significant difference between
reported carbohydrate and calculated NFE values.
Finally, animal-sourced and plant-sourced ingredients
were compared between grain-free and grain-containing
diets, with the hypothesis that there would be no signifi-
cant difference in the most commonly reported food
allergens in grain-free vs grain-containing diets.
Materials and methods
Diet selection
A list of dry cat diet manufacturers was created from all
diets offered for sale on two popular internet pet food
retailers’ websites (petfooddirect.com; chewy.com). For
the purposes of the study, an individual manufacturer
was defined by having a unique main corporate address,
which was assumed to have common management and
manufacturing sites, even if they produced multiple prod-
ucts sold under different names. All manufacturers with
corporate headquarters outside of the USA were excluded.
Since some manufacturers sell both mass-market and
‘premium’ brands of diets (which may use different ingre-
dients and formulations), we recorded whether each man-
ufacturer had diets sold on the mass market (eg, grocery
stores, superstores/big-box stores), only in specialty
stores (eg, pet supply stores, pet boutique stores) or both.
Procedures
For each manufacturer, a list of all flavors and varieties
of dry adult cat diets that were available for sale on the
sites was compiled. The list included all diets that were
marketed as being for adult maintenance and included
diets with an Association of American Feed Control
Officials (AAFCO) nutritional adequacy statement indi-
cating that the diet had passed feeding trials or was for-
mulated to meet the AAFCO Nutrient Profile for adult
cat maintenance or all life stages.5 Diets that were mar-
keted specifically for kittens were excluded. Any diets
with labels that contained wording implying special
needs, such as ‘indoor’, ‘urinary tract health’, ‘breed spe-
cific’ or ‘hairball control’ were also excluded. The final
list included 224 diets.
Ingredient lists of all eligible diets were reviewed and
grains were defined as any food made from wheat, rice,
oats, corn, barley or another cereal grain. As per the US
Department of Agriculture definition of the word ‘grain’,
this included both the whole-grain products (which
include the entire grain kernel of the bran, the germ and
the endosperm), as well as refined-grain products that
have been milled to remove the bran and germ.6 The
diets were categorized as containing grains if there was a
grain or grain-derived product in the ingredient list
(grain-containing group) and as ‘grain-free’ (grain-free
group) if they did not contain any recognizable grains or
grain-derived ingredients on the ingredient list or were
marketed as being ‘grain-free’ by the manufacturer, even
if there was a grain in the ingredient list.
Of the 224 diets identified, some were from the same
manufacturer. To ensure that one manufacturer’s diets
were not over-represented, a computerized randomiza-
tion scheme was used to select one diet from each manu-
facturer for each diet group (grain-free vs grain-containing).
In addition, if a manufacturer sold diets in both mass-
market and specialty stores, one diet from each of these
categories was selected in the grain-containing and grain-
free groups. Therefore, from an individual manufacturer,
between one (one grain-containing or one grain-free) and
four (two grain-containing and two grain-free) diets were
selected for the study for a total of 77 diets.
For each diet included in the study, manufacturers’
customer service lines were contacted and asked to pro-
vide ‘carbohydrate content’ on a metabolizable energy
basis (in g/1000 kcal). If the manufacturer could only
provide the carbohydrate content on an as-fed percent
basis, the energy density (kcal/kg) was also obtained
from the manufacturer and the as-fed carbohydrate
content was converted to a g/1000 kcal value. If the
manufacturer could only provide the carbohydrate
content on a dry matter basis, the moisture content was
obtained and the carbohydrate content was converted
to g/1000 kcal.
From the complete list of diets included in the study
(n = 77), a subset of approximately 25% (n = 20) was
selected using a random number generator from the
grain-containing and grain-free diet groups (grain
Prantil et al 3
group: n = 11; grain-free group: n = 9). Each of these
diets was purchased online. Each diet was mixed thor-
oughly, and 250 g samples were removed, repackaged
and coded so that the laboratory personnel were blinded
to the identity of the samples during diet testing. All of
the diet samples were shipped to a commercial labora-
tory (Midwest Laboratories, Omaha, NE, USA) regularly
used by the pet food industry for diet analysis. A single
proximate analysis that included moisture, crude fat,
ash, crude protein and crude fiber was run on each diet
sample. The percentage NFE was then calculated by the
laboratory using the formula NFE = 100 – (crude protein
+ crude fat + crude fiber + moisture + ash). The energy
density of the diet was calculated using modified
Atwater factors and used to convert these values to
g/1000 kcal.7 The NFE values were then compared with
the manufacturer-reported carbohydrate content.
To assess ingredients, each diet’s ingredient list was
reviewed and major animal and plant sources of protein
and carbohydrate in the diet were recorded. Fats such as
fish oil, animal fat and vegetable oils were not included
in the analysis. Ingredients that followed the vitamins
and minerals in the ingredient list were deemed to be
present in only trace amounts and were also excluded.
To facilitate analysis, some of the animal-sourced ingre-
dients were grouped into larger categories if they were
rare (eg, calamari was grouped with clam in the seafood
category), if they were derived from the same proteins
(eg, cheese and yogurt both coming from milk) or if it
was not clear which specific species were contained in
each ingredient (eg, ‘poultry’ or ‘fish’ or ‘meat’ could
include multiple species that were all individually
included in other diets). As such, the ‘poultry’ category
included the following ingredients: poultry, chicken, tur-
key, pheasant and duck. The ‘fish’ category included the
following ingredients: fish, salmon, whitefish, ocean
fish, trout, herring, menhaden and tuna. The ‘dairy’ cat-
egory included the following ingredients: whey, yogurt,
milk, cheese and cottage cheese. The ‘seafood’ category
included the following ingredients: mussel, crab, clam
and calamari. The ‘meat’ category included the follow-
ing ingredients: meat, meat meal and animal digest.
Overall, there were 12 animal-sourced ingredients or cat-
egories. There were 42 different major plant-sourced
ingredients and these were not further grouped. These
main protein categories and individual carbohydrate
ingredients were compared between grain-containing
and grain-free diets.
Statistical analysis
Data distributions were evaluated graphically, and since
all data were normally distributed, data are presented
as mean ± SD. The carbohydrate content reported by
manufacturers was compared between grain-containing
and grain-free diets using an independent t-test. For the
subgroup of diets that underwent nutrient analysis, the
calculated NFE vs reported carbohydrate content was
compared using a paired t-test. Major protein catego-
ries and carbohydrate ingredients in each diet were
compared between grain-containing and grain-free
diets using χ2 tests. Data were analyzed with commer-
cial statistical software (Systat 13.0 [Systat Software]
and SPSS version 22 [IBM]), and P <0.05 was consid-
ered significant.
Results
Of the 77 diets included in the study, three manufactur-
ers were unable to provide information on carbohydrate
content on an energy basis. Two of these manufacturers
provided dry matter carbohydrate values from a typical
analysis (average dry matter carbohydrate content or
maximum dry matter carbohydrate content) and aver-
age moisture levels from which carbohydrate content on
an energy basis was calculated. The third manufacturer
did not respond to repeated requests over several
months to provide the carbohydrate content of the diet,
resulting in a total study population of 76 diets for the
carbohydrate content comparison between grain-
containing and grain-free diets. When the subset of diets
was randomly selected for diet analysis, in anticipation
of being able to get the requested information from all
manufacturers, this diet was counted in the calculation
of the 25% subset of grain-containing diets. Without
reported carbohydrate content, this product could only
be included in the ingredient evaluation as an ingredient
list was available on the manufacturer’s website.
Therefore, a total of 77 diets were included in the ingre-
dient comparison portion of the study.
The manufacturer-reported carbohydrate content of
the grain-containing diets (n = 41; 86 ± 22 g/1000 kcal)
was significantly higher than that of the grain-free group
(n = 35; 64 ± 16 g/1000 kcal [P <0.001]; Figure 1). When
diets typically sold in specialty stores were compared
with mass-market diets, reported carbohydrate content
was higher in the mass market (n = 12, 93 ± 17 g/1000
kcal) than in the specialty diets (n = 64, 72 ± 22 g/1000
kcal; P = 0.003), all inclusive of grain-free and grain-
containing diets (Figure 2).
For the subgroup of 20 grain-containing and grain-
free diets for which NFE content was calculated from
analysis, the reported carbohydrate content (79 ± 30
g/1000 kcal) from the manufacturers was significantly
higher than the NFE calculated from analysis (73 ± 27
g/1000 kcal; P = 0.024) The calculated NFE content of
the grain-containing diets (n = 11; 90 ± 19 g/1000 kcal)
was higher than that of the grain-free diets (n = 9; 52 ±
20 g/1000 kcal; P <0.001).
The grain-containing diet group contained eight cat-
egories of animal-sourced ingredients and 35 unique
plant-sourced ingredients. In the grain-free diet group,
4 Journal of Feline Medicine and Surgery 00(0)
10 categories of animal-sourced ingredients and 32
unique plant-sourced ingredients were identified, one of
which was a grain by the US Department of Agriculture
definition.6 Tables 1 and 2 show ingredients that were
present in more than one diet of the total 77 diets. Other
ingredients – venison, bison, avocado, apricot, artichoke,
chia, papaya and zucchini – were each only present in
either one grain-free diet and no grain-containing diets
or one grain-containing diet and no grain-free diets and
were excluded from statistical analysis. The most com-
mon animal-sourced ingredient category in the grain-
containing diets was poultry, while poultry and fish tied
as the most common ingredients in the grain-free foods.
The most common plant-sourced ingredients in the
grain-containing diets were rice, flax and cranberry vs
pea, cranberry and potato in the grain-free diets. Poultry
(P = 0.009), which included chicken, a commonly
reported food allergen, was significantly more common
in the grain-containing diets than in the grain-free diets.
For the plant-sourced ingredients, all grains and soy
were significantly more common (P <0.05) in grain-con-
taining diets than grain-free diets, while chickpea, lentil,
pea, potato, sweet potato and cassava/tapioca were sig-
nificantly more common (P <0.05) in the grain-free diets.
Figure 1 Boxandwhisker plot of the carbohydrate content
of grain-free and grain-containing dry feline diets. Each box
represents the interquartile range (25th–75th percentiles), the
horizontal line in each box represents the median value, the
whiskers indicate the range of observed values that fall within
± 1.5 times the interquartile range, and circles represent
outliers
Figure 2 Boxandwhisker plot of the carbohydrate content
of dry feline diets available in mass market retailers as
compared with specialty retailers. Each box represents the
interquartile range (25th–75th percentiles), the horizontal
line in each box represents the median value, the whiskers
indicate the range of observed values that fall within ± 1.5
times the interquartile range, and circles represent outliers
Table 1 Comparison of animal-sourced ingredients in grain-containing (n = 42) and grain-free (n = 35) dry cat diets
Protein source Number of grain diets Number of grain-free diets P value
Beef 0 2 0.203
Dairy* 4 5 0.724
Egg 26 17 0.259
Fish30 25 1.000
Lamb 3 0 0.246
Meat3 0 0.246
Pork 2 4 0.402
Poultry§40 25 0.009
Rabbit 0 2 0.203
Seafood4 1 0.369
*Included whey, yogurt, milk, cheese and cottage cheese
Included fish, salmon, whitefish, ocean fish, trout, herring, menhaden and tuna
Included meat, meat meal and animal digest
§Included poultry, chicken, turkey, pheasant and duck
Included mussel, crab, clam and calamari
Prantil et al 5
Discussion
The mean manufacturer-reported carbohydrate content
of the grain-free diets was 25% lower than the reported
carbohydrate content of the grain-containing diets,
which did not support our hypothesis. However, there
was considerable overlap between the two groups, and
within each group, individual diets varied widely in car-
bohydrate content.
The physiological and clinical relevance of this 25%
difference is unclear since, while cats do have some met-
abolic differences related to carbohydrate metabolism
compared with many other species, they are able to
digest and metabolize carbohydrates. Cats have low
hepatic glucokinase activity, which is the primary
enzyme used by most animals to phosphorylate glucose
inside hepatic cells as the first step in glycolysis when
blood glucose levels are high, such as after meals con-
taining carbohydrates.8 Adult cats, as well as many other
mammals, have no dietary requirement for carbohy-
drate.9 In one study, cats preferred to consume a diet
containing about 8 g carbohydrate daily, and were reluc-
tant to consume more than 20 g of carbohydrate daily.
These amounts would be provided by a diet containing
40 g and 100 g of carbohydrate/1000 kcal, respectively,
for a cat consuming 200 kcal.10 However, these results
may be related to the specific diets used in the study, and
may not be generalizable to all cats. Safe upper limits
have been described for some specific types of carbohy-
drates (including glucose, sucrose and lactose) in cat
diets, but not for overall carbohydrate, assuming protein
Table 2 Comparison of plant-sourced ingredients in grain-containing (n = 42) and grain-free (n = 35) dry cat diets
Carbohydrate source Number of grain diets Number of grain-free diets P value
Alfalfa 6 10 0.162
Apple 9 11 0.435
Barley 13 1 0.002
Beet 14 9 0.618
Blackberry 1 2 0.588
Blueberry 13 15 0.344
Broccoli 4 3 1.000
Carrot 16 16 0.643
Cauliflower 0 2 0.230
Celery 2 5 0.235
Chickpea 0 6 0.007
Chicory 9 8 1.000
Corn 12 0 0.000
Cranberry 20 18 0.821
Flax 24 15 0.256
Green beans 0 2 0.203
Kelp 9 4 0.361
Lentil 1 6 0.042
Lettuce 2 4 0.402
Millet 5 0 0.059
Oat 19 0 0.000
Pea 14 32 0.000
Pomegranate 1 1 1.000
Potato 8 17 0.008
Pumpkin 5 5 1.000
Raspberry 1 2 0.588
Rice 34 0 0.000
Sorghum/milo 3 0 0.246
Soy 8 0 0.007
Spinach 9 9 0.788
Sweet potato 7 15 0.021
Tapioca/cassava 0 12 0.000
Tomato 11 7 0.596
Watercress 2 4 0.402
Wheat 7 0 0.014
Yucca 1 1 1.000
6 Journal of Feline Medicine and Surgery 00(0)
and fat needs are met.11 Under the known limits, the data
show that cats can efficiently digest and metabolize car-
bohydrates,12 utilizing enzymes such as hexokinase to
metabolize carbohydrates through the traditional path-
ways of glycolysis through oxidative phosphorylation.
In addition cats can obtain not only energy but other
nutrients, such as fiber, protein, vitamins and minerals
from plant (carbohydrate) ingredients, in their diets.
While differences in postprandial glucose and insulin in
healthy cats fed diets of differing carbohydrate concen-
trations have been reported,13,14 clear clinical conse-
quences to these differences in healthy cats remain
undocumented. Therefore, any clinical implications of
the mean 25% lower carbohydrate content found in the
current study will require additional research.
The current study only looked at the total amount of
carbohydrate, and not the source or type of carbohy-
drate, which also is important as not all carbohydrate
ingredients in pet foods have equivalent nutritional pro-
files or physiologic effects. In addition, dietary carbohy-
drate is not in isolation – processing and interaction with
other diet ingredients can also alter physiologic effects.
Whole grains often contain more protein and less sugar
and simple carbohydrates than common non-grain car-
bohydrate sources used in cat diets such as tapioca and
potatoes. These ingredients may have differing effects
on insulin release, gut function and other metabolic
activities that cannot be predicted based solely on the
total reported carbohydrate content. Evaluation of these
additional factors is warranted in future studies.
Regardless of any potential clinical importance, eval-
uating carbohydrate content in pet diets is a challenge
for not only the pet food consumer, but also for veteri-
nary medical professionals who want to have the most
accurate information available in order to compare and
contrast different pet diets. In comparing the different
tests offered by three different commercial laboratories
that specialize in food/feed nutrient analysis for this
study (Midwest Laboratories, Eurofins Scientific,
Covance), there were no standard analytes that could be
compared across the board; each laboratory had differ-
ent inclusions for tests deemed as ‘carbohydrate analy-
ses’. For example, one laboratory offered 23 different
assays in the category of carbohydrate testing with
almost no overlap of what specific compounds were
being measured, and another manufacturer only offered
NFE. This discrepancy is likely because there are many
types of carbohydrates and it can be difficult and expen-
sive to distinguish the individual components. However,
the type of monosaccharides and the bonds that connect
them are important as the metabolism of the different
carbohydrates depends on them. There is little regula-
tory guidance in this regard currently, although the
AAFCO has organized a carbohydrate working group to
address the matter of carbohydrates in pet food. A stand-
ard method of measuring and reporting carbohydrate
content would be ideal, but owing to the nature of carbo-
hydrates, condensing this information down into one
single value for assessing and reporting accurate carbo-
hydrate content may not be possible.
Currently, the most commonly reported value relating
to carbohydrate content is NFE. As an estimate of carbo-
hydrate content, NFE has a number of limitations. Owing
to the nature of the NFE equation, any errors in analyses
of other nutrients will result in alterations in the NFE.
One example is that the NFE equation uses crude fiber,
which typically underestimates the amount of total fiber
that is present in pet diets and can result in higher calcu-
lated NFE.15 In addition to inaccuracies from the equation
itself, using guaranteed analysis values (minimums and
maximums) rather than average or typical analyses to
estimate NFE will lead to even greater inaccuracies.
Because NFE is the most common way of represent-
ing carbohydrates in pet food currently, it is likely that
many manufacturers were providing NFE when asked
for diet carbohydrate content for this study, but this is
not known for sure. The differences seen between manu-
facturer-reported carbohydrate content and calculated
NFE in this study could thus be due to use of different
carbohydrate assays (NFE vs other measurements), vari-
ation in assays for crude protein, moisture, ash, crude
fiber and crude fat from the laboratories used by the
manufacturers to calculate NFE vs the laboratory used
for this study, or to variations in the actual nutrient con-
centrations between batches of diet as only one bag of
each diet was analyzed in this study.
The final objective of this study was to compare ingre-
dients and investigate potential allergens in grain-
containing vs grain-free diets. Although, anecdotally,
many cat owners appear to believe that grains are a com-
mon cause of allergies in cats, studies of food sensitivities
and allergies do not bear this belief out. In one study of
55cats with chronic idiopathic gastrointestinal problems,
only 29% were diagnosed as having food sensitivities.4
Another study of 128 cats with pruritus or gastrointestinal
signs confirmed only 17% as food allergic.16 The rate in
the general cat population would be assumed to be dra-
matically lower than in these two very selected popula-
tions. The most commonly reported allergens in cat diets
are animal protein sources such as beef, dairy, fish,
chicken and lamb, with plant sources such as barley and
wheat less common and other plant-sourced ingredients
even rarer.3 Multiple sensitivities are even more infre-
quent, making claims of allergy to ‘all grains’ an unlikely
scenario for cats.2
In the current study, besides all of the grains (which
was expected), poultry and soy were the only ingredi-
ents that were significantly less common in the grain-
free diets than the grain-containing diets. Chicken has
been reported to be one of the more common causes of
food allergies in cats, but other ingredients such as beef
and dairy products that are also reported to be causes of
Prantil et al 7
food allergies in cats were just as common in grain-free
diets. The greater inclusion of poultry and soy in the
grain-containing vs grain-free diets may reflect current
marketing trends to include more exotic ingredients
than chicken. Several exotic ingredients such as venison,
rabbit and bison were seen in this study only in grain-
free foods. There also seems to be a trend for companies
to specifically advertise that their foods contain no soy.
As such, these differences may reflect the philosophy of
the manufacturer or the desires of the customer base
rather than having any relation to whether the diet does
or does not contain grains.
There are a number of limitations to this study. The
total number of dry cat diets on the market is hard to
define and will vary based on how manufacturers are
selected. This study used online searches of retailers and
it is likely that some manufacturers were excluded
because they are not sold by these online retailers.
Therefore, the population of diets used in this study may
not accurately reflect the total population of dry cat diets
available for sale in the USA. This is particularly likely in
the case of comparing products from pet specialty stores
to those from mass-market channels. Pet foods sold on
the mass market are less likely to be also available online,
which is how the foods in this study were chosen, so the
mass market diets that were included in this study may
not be representative of overall mass market diets. The
study may also not be appropriately powered for detailed
ingredient comparisons between the diets as this was a
secondary aim rather than the primary one. Only one
sample of each diet was analyzed for financial reasons
and while a product with good-quality control should
have a similar analysis from batch-to-batch, inter-batch
variability is certainly possible, especially among brands
with less reliable quality-control measures. A major, but
unavoidable, limitation was the use of the NFE as a sur-
rogate of the carbohydrate content value and the assump-
tion that the manufacturers were providing NFE when
asked for the carbohydrate content. Future studies could
attempt to investigate the specific methods used by each
manufacturer to determine carbohydrate content or
investigate both carbohydrate type and amounts.
Conclusions
The grain-free dry cat diets included in this study had
lower carbohydrate values than the grain-containing
diets, but individual diets varied widely in both type and
amount of carbohydrate ingredients and all of the diets
contained measurable carbohydrates. Although many pet
owners that select grain-free diets may worry about food
allergies, many common allergens were just as frequently
found in the grain-free diets. Selecting a grain-free diet is
thus no guarantee that lower carbohydrate content or
fewer common food allergens are being fed.
Conict of interest The authors declared no potential con-
flicts of interest with respect to the research, authorship, and/
or publication of this article.
Funding Dr Prantil’s residency was funded by VCA Antech
and Mars Petcare. This project was supported by VCA Antech.
References
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... Lignin, which is not a fermentable fraction, has been demonstrated to facilitate fecal formation and accelerate the passage of contents through the gastrointestinal tract [76]. The digestible carbohydrates (NFE) present in extruded foods typically reach levels of around 40-60 g/100 g DM [78,79], which is consistent with the results obtained, where the average NFE content was 51.33 g/100 g DM. These carbohydrates serve as a source of readily available energy. ...
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Since the legalization of insect protein in pet food, a variety of products incorporating this ingredient have emerged on the market. Although edible insects are acknowledged for high protein content, chitin can also elevate the quantity of indigestible carbohydrates. The objective of this study was to evaluate the nutritional adequacy of fourteen complete dog foods containing edible insects in accordance with the FEDIAF nutritional guidelines. Due to the use of insects as the predominant animal component in all diets, analyses of dietary fiber fractions were carried out to estimate the content of indigestible carbohydrates. The analyses included the assessment of chemical composition, calcium, and phosphorus levels and metabolizable energy. The findings were then compared with the data provided by the manufacturers. All diets were found to meet the minimum recommended levels from the FEDIAF nutritional guidelines for protein (18.0 g/100 g DM) and fat (5.5 g/100 g DM). However, discrepancies were noted between the label data and analysis results. The results for the dietary fiber fraction differed from the crude fiber content, which is consistent with the imprecision inherent to the crude fiber determination method. In one food, there was a discrepancy of up to 19.21 g between the NDF fraction and the crude fiber content. Calcium levels were inadequate in two foods, and furthermore, twelve foods exhibited an abnormal calcium/phosphorus ratio. These findings indicate that while edible insects can be a valuable protein source, their inclusion may lead to increased indigestible carbohydrates, potentially causing digestive issues and gastric discomfort in dogs.
... Further, grain-free diets can be lower, similar, or higher in carbohydrate content compared to other diet categories. 8,24 There has been considerable attention to the association between dilated cardiomyopathy (DCM) in dogs and the use of grain-free diets, 25,26 and both veterinarians and pet owners might have increased awareness of this issue. Regardless, given that more than 1 in 5 dogs in the present study were fed a grain-free diet before a cancer diagnosis, this data highlights the need for clinicians to discuss the risk of diet-associated DCM with all dog owners. ...
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Background Many dog owners alter their dog's nutritional regimen after a diagnosis of cancer. There are limited data as to specific changes made and reasons behind these changes. Hypothesis/Objectives To collect updated and detailed data on changes made by owners to their dog's diet and supplements after a cancer diagnosis. Animals Responses were collected from a survey of dog owners who brought their dogs to the UC Davis Veterinary Medical Teaching Hospital's Oncology Service for the first time after a cancer diagnosis. Dogs with recurrence or presenting for a second type of cancer were excluded. Methods Eligible owners were surveyed between December 2020 and March 2022. The survey contained 62 questions regarding diet, supplement use, and treats, and how these were altered after a cancer diagnosis. Responses were matched to medical record data. Results One hundred twenty‐eight surveys were retained for analysis, including 120 respondents that completed the survey. In response to a cancer diagnosis, 54.8% (95% CI; 45.7%‐63.8%) of owners altered diets or supplements or both. The most common informational resource for dog diets was veterinarians (53.9%). Usage of home‐prepared foods significantly increased after a cancer diagnosis (P = .03). There was no significant difference in commercial diet usage before or after a diagnosis (P = .25). Joint support products were the most common supplements given both before (37.4%) and after (35.0%) diagnosis. Conclusions and Clinical Importance Many dog owners alter their dog's nutritional intake after a cancer diagnosis. These owners should be provided information relating to commonly observed alterations, including home‐prepared foods and supplements.
... Grain-free diets in the pet food industry are diets that do not use traditional grains such as wheat, corn and rice flours. Instead, these diets use pulses such as peas, chickpeas and lentils, potatoes and other ingredients as their carbohydrate source [1]. Pulses are feed ingredients that have been used in many dog foods over the past two decades [2]. ...
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In 2018, the US Food and Drug Administration reported a link between canine dilated cardiomyopathy (DCM) and grain-free diets. Evidence to support a link has emerged, but the specific ingredients responsible and the role of taurine or other causative factors remain unclear. We hypothesized dogs fed pulse-based, grain-free diets for 28 days will show decreased macronutrient digestibility, increased fecal bile acid excretion, and reduced plasma cystine, cysteine, methionine and taurine, causing sub-clinical cardiac or blood changes indicative of early DCM. Three diets were formulated using white rice flour (grain), whole lentil (grain-free), or wrinkled pea (grain-free) and compared to the pre-trial phase on a commercial grain-based diet. After 28 days of feeding each diet, the wrinkled pea diet impaired stroke volume and cardiac output, increased end-systolic ventricular diameter and increased plasma N-Terminal Pro-B-type Natriuretic Peptide (NT-ProBNP), albeit in a sub-clinical manner. Digestibility of some macronutrients and sulphur-containing amino acids, excluding taurine, also decreased with pulse-based compared to grain-based diets, likely due to higher fiber levels. Plasma taurine levels were unchanged; however, plasma methionine was significantly lower after feeding all test diets compared to the commercial diet. Overall, DCM-like changes observed with the wrinkled pea diet, but not lentil diet, after only 4 weeks in a breed not known to be susceptible support a link between pea-based diets and canine nutritionally-mediated DCM.
... The percentage NFE was then calculated by the laboratory using the formula NFE = 100 − (crude protein + crude fat + crude fiber + moisture + ash) % [27], moisture was determined according to the procedure by Chinese standard GB/T 6435-2014. In addition, 5.0 g of each plant sample were weighed and completely dried for 4 h at 103 • C. ...
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It is important to select buckwheat varieties suitable for foraging and determining their best harvest time as increasing attention was paid to the forage value of buckwheat. Here, eight tartary buckwheat varieties were identified as suitable for forage based on their potential forage value through assaying the contents of ash, crude protein, crude fiber, crude fat, acid detergent fiber, neutral detergent fiber, nitrogen free extract, calcium, phosphorus, total flavonoids, and rutin in these tartary buckwheat varieties at flowering, pustulation, and mature stages, respectively. In addition, analysis of relative feed value (RFV), relative forage quality (RFQ), and principal component analysis (PCA) based on the assayed contents was applied for comprehensive evaluation of these tartary buckwheat varieties. Results showed that all the eight tartary buckwheat varieties possessed potential high forage value as their RFV is from 121.31% to 217.39% and RFQ from 117.26% to 224.54% at all three stages. In particular, both RFV and RFQ values of PS-07 reached the highest at the flowering stage among the eight tartary buckwheat varieties, followed by CQ-3 and EWPS. Accordingly, the comprehensive scoring of principal component values of PS-07 and CQ-3 are relatively higher at the flowering stage. Our research thus revealed that the eight tartary buckwheat varieties are all suitable for forage, and also provided an experimental basis for selecting the eight tartary buckwheat varieties harvested at different growth stages for livestock forage.
... Grain-free diets were defined as those not containing grains or grain-derived ingredients. 14,17,27 Oils (eg, corn oil) were not classified as a grain product. ...
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Background Recent studies have investigated dogs with presumed diet‐associated dilated cardiomyopathy (daDCM), but prospective studies of multiple breeds are needed. Hypothesis/Objectives To evaluate baseline features and serial changes in echocardiography and cardiac biomarkers in dogs with DCM eating nontraditional diets (NTDs) or traditional diets (TDs), and in dogs with subclinical cardiac abnormalities (SCA) eating NTD. Animals Sixty dogs with DCM (NTD, n = 51; TDs, n = 9) and 16 dogs with SCA eating NTDs. Methods Echocardiography, electrocardiography, and measurement of taurine, cardiac troponin I, and N‐terminal pro‐B‐type natriuretic peptide were performed in dogs with DCM or SCA. Diets were changed for all dogs, taurine was supplemented in most, and echocardiography and cardiac biomarkers were reassessed (3, 6, and 9 months). Results At enrollment, there were few differences between dogs with DCM eating NTDs or TDs; none had low plasma or whole blood taurine concentrations. Improvement in fractional shortening over time was significantly associated with previous consumption of a NTD, even after adjustment for other variables (P = .005). Median survival time for dogs with DCM was 611 days (range, 2‐940 days) for the NTD group and 161 days (range, 12‐669 days) for the TD group (P = .21). Sudden death was the most common cause of death in both diet groups. Dogs with SCA also had significant echocardiographic improvements over time. Conclusions and Clinical Importance Dogs with DCM or SCA previously eating NTDs had small, yet significant improvements in echocardiographic parameters after diet changes.
... In general, plant-based protein sources are more widely accepted in canine diets, as dogs are classified as omnivores. In contrast, as obligate carnivores, the use of plant-based ingredients in feline diets is often questioned by consumers (Prantil et al., 2018). However, as observed in the current study and in previous studies, plant-based ingredients can be valuable inclusions in feline diets. ...
Article
Garbanzo beans (GB; Cicer arietinum) are a readily available pulse crop that have gained popularity as a plant-based protein source in the pet food industry. However, raw GB contain anti-nutritional factors that can reduce digestibility and cause digestive upsets in pets that are undesirable to owners. The objective of this study was to determine the effects of the inclusion of raw or cooked GB in extruded feline diets on macronutrient digestibility, gastrointestinal tolerance, and fermentative end-products in cats. Five diets were formulated to contain raw GB at 0, 7.5, 15, or 30% or cooked GB at 30%. Ten adult, male cats (mean age: 1.0 ± 0.0 yr, mean BW: 4.7 ± 0.4 kg) were used in a replicated 5x5 Latin square design. Each period consisted of 14 d, with 10 d of diet adaptation followed by 4 d of total fecal and urine collection. At the end of each period, 4 mL of blood were collected and analyzed for a serum chemistry and complete blood count to ensure all animals remained healthy throughout the study. Cats were fed twice daily and food intake was calculated to maintain body weight. Food intake was highest (P < 0.05) for cats fed 0% raw GB (72.2 g/d, DMB) compared with GB inclusions of 7.5% or greater (average 70.3 g/d, DMB). Dry matter and organic matter apparent total tract digestibility (ATTD) were lowest (P < 0.05) for cats consuming the 30% cooked GB diet (77.3% and 81.7%, respectively). Cats fed 7.5% raw GB had greater (P < 0.05) crude protein ATTD (86.2%) than cats fed 15% raw GB (82.3%) or 30% cooked GB (81.6%). Total short-chain fatty acid (SCFA) concentrations were highest (P < 0.05) for 30% cooked GB at 682 μmol/g but not different (P > 0.05) than 15% GB (528 μmol/g) or 30% raw GB (591 μmol/g) diets. In terms of fecal microbial abundance, the predominant phyla were Firmicutes, Bacteroidota, and Actinobacteria. Cats fed the 0% GB diet had a greater relative abundance of Firmicutes (62.1%) and Fusobacteria (4.0%) than the remaining diets (average 54% and 1.6%, respectively). In conclusion, all inclusion levels of raw GB resulted in high digestibility (average > 80%) and ideal fecal scores (average 2.9), demonstrating their adequacy as a protein source in feline diets up to a 30% inclusion level.
... Pet foods are marketed strategically to owners, with trendy claims such as "organic, " "natural" and "grain-free" often found with premium pet foods (4). Grainfree diets exclude the use of grains such as wheat, corn, or rice flours and instead incorporate pulses such as peas, lentils and fava beans as the major carbohydrate source (5). While pulses are common dietary ingredients for both humans and animals, they are considered to be highly nutritious primarily due to their high levels of protein, in addition to carbohydrate, fiber, vitamins and minerals (6). ...
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Grain-based carbohydrate sources such as rice comprise 30–50% of commercial pet foods. Some pet foods however have removed the use of grains and have instead incorporated pulses, such as peas and lentils, resulting in grain-free diets. The hypothesis was dog diets with higher levels of dietary fiber will produce a low glycemic response due to decreased rates of digestion and lowered bioavailability of all macronutrients and increased fecal bile salt excretion. This in turn was hypothesized to produce lower plasma concentrations of cysteine, methionine and taurine after 7 days of feeding each test diet in dogs. Six diets were formulated at an inclusion level of 20% available carbohydrate, using white rice flour (grain) or whole pulse flours from smooth pea, fava bean, red lentil or 2 different wrinkled pea varieties (CDC 4,140–4 or Amigold) and fed to beagles in a randomized, cross-over, blinded design. After 7 days feeding each diet, fasting blood glucose was the lowest in the lentil (3.5 ± 0.1 mmol/L) and wrinkled pea (4,140–4; 3.6 ± 0.1 mmol/L) diet periods, while peak glucose levels was lowest after feeding the lentil diet (4.4 ± 0.1 mmol/L) compared to the rice diet. Total tract apparent digestibility of all macronutrients as well as taurine differed among diets yet plasma taurine was not outside normal range. Decreased macronutrient and amino acid digestibility was associated with increasing amylose and dietary fiber content but the specific causative agent could not be determined from this study. Surprisingly, digestibility decreases were not due to increased bile salt loss in the feces since increasing dietary fiber content led to decreased fecal bile salt levels. In conclusion, although pulse-based canine diets have beneficial low glycemic properties, after only 7 days, these pulse-based diets decrease macronutrient and amino acid digestibility. This is likely related at least in part to the lower animal protein content, but on a long-term basis could put domestic dogs at risk for low taurine and dilated cardiomyopathy.
... Grain-containing or grain-derived ingredients included whole-grain products or refined-grain products made from any part of wheat, rice, oats, corn, barley, or another cereal grain. 19 Oils were not considered a grain product. Diets were separately categorized as having FDAlisted ingredients of concern (peas, lentils, or potatoes) in the top 10 ingredients (FDA-PLP) or as without FDA-listed ingredients of concern (peas, lentils, or potatoes) in the top 10 ingredients (NoFDA-PLP). ...
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Background Associations of diet with dilated cardiomyopathy are under investigation. Objectives That cardiac assessment would show abnormalities in healthy dogs eating grain‐free (GF) diets or diets with Food and Drug Administration (FDA)‐listed ingredients of concern (peas, lentils, or potatoes) as top 10 ingredients (FDA‐PLP), but not in dogs eating grain‐inclusive (GI) diets or diets without FDA‐listed ingredients of concern (PLP) in the top 10 ingredients (NoFDA‐PLP). Animals One hundred eighty‐eight healthy Doberman Pinschers, Golden Retrievers, Miniature Schnauzers, and Whippets. Methods This study was an observational cross‐sectional study. Echocardiograms, cardiac biomarkers, and blood and plasma taurine concentrations were compared between dogs eating GF (n = 26) and GI (n = 162) diets, and between FDA‐PLP (n = 39) and NoFDA‐PLP (n = 149) diets, controlling for age and breed. Demographic characteristics, murmurs, genetic status, and ventricular premature complexes (VPCs) during examination were compared between dogs eating different diet types. Results No differences in echocardiographic variables, N‐terminal pro‐B‐type natriuretic peptide or whole blood taurine were noted between dogs eating different diet types. Dogs eating GF diets had higher median high‐sensitivity cardiac troponin I (hs‐cTnI) (GF 0.076 ng/mL [Interquartile range (IQR), 0.028‐0.156] vs. GI 0.048 [IQR, 0.0026‐0.080]; P < .001) and higher median plasma taurine (GF 125 nmol/mL [IQR, 101‐148] vs GI 104 [IQR, 86‐123]; P = .02) than dogs eating GI diets. Dogs eating FDA‐PLP diets had higher median hs‐cTnI (0.059 ng/mL [IQR, 0.028‐0.122]) than dogs eating NoFDA‐PLP diets (0.048 [IQR, 0.025‐0.085]; P = .006). A greater proportion of dogs eating FDA‐PLP diets (10%) had VPCs than dogs eating NoFDA‐PLP diets (2%; P = .04). Conclusions and Clinical Importance Higher hs‐cTnI in healthy dogs eating GF and FDA‐PLP diets might indicate low‐level cardiomyocyte injury.
... La rhétorique des marques de croquettes sans céréales est basée sur l'association faite entre les céréales et l'amidon, d'une part, et le fait que le chien "sauvage" ne mangerait pas de céréales, d'autre part. Concernant le taux de glucides, celui des aliments sans céréales est légèrement plus bas (64 ± 16 g/1000 kcal EM) que celui des aliments standards (86 ± 22 g/1000 kcal EM) 43 . Cependant, compte tenu de l'importante diversité des taux de glucide à l'intérieur de chacune des catégories, on peut aisément trouver un aliment sans céréales contenant plus de glucides qu'un aliment standard. ...
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Par défiance des aliments industriels, à la suite d'informations trouvées sur internet, à des croyances, à une réflexion éthique.. . les propriétaires d'animaux se tournent, pour une part non négligeable, vers des rations que nous qualifierons de non conventionnelles. Cette qualification est mal définie, et regroupe plusieurs grands « types" de rations, des rations crues aux rations sans céréales en passant par les rations végétariennes. Mais, l'un des points communs à toutes ces rations est la motivation du propriétaire. Ainsi, dans le cadre des rations non conventionnelles, il y a une recherche d'alternative aux rations industrielles ou ménagères, non pas avec comme premier objectif d'avoir un apport équilibré en nutriments, mais de répondre à une certaine croyance ou orthodoxie alimentaire. Cette doctrine peut trouver son origine dans la recherche d'une alimentation plus saine ou plus adaptée à l'image que le propriétaire se fait de son animal. Ainsi, dans l'accompagnement et le conseil du propriétaire, dans l'intérêt de l'animal, il est essentiel de comprendre la base des motivations du propriétaire, afin d'identifier les leviers d'action. En effet, la motivation derrière le choix d'une ration n'est pas toujours rationnelle. Et quand elle l'est, le raisonnement sous-jacent n'est pas toujours soutenu par des preuves scientifiques, mais, le plus souvent, par des sophismes et arguments fallacieux. La discussion avec le propriétaire peut aussi être perturbée par un effet Dunning-Kruger. De plus, il existe un fort engagement de la part des propriétaires et des promoteurs de ce genre de pratique tenant de la conviction et laissant peu de place à l'argumentation. Par exemple, l'un des premiers articles sur l'équilibre des rations BARF en 2001 a fait l'objet de nombreuses lettres à l'éditeur. L'un des arguments les plus avancés est que les auteurs de ces études sont "contre" ces pratiques non conventionnelles, déplaçant ainsi la discussion du registre scientifique à celui d'opinion. De la vision de l'auteur, le conseil et l'accompagnement du propriétaire doivent se baser sur son information par la présentation de preuves apportées par la science, sans juger, ni nécessairement tenter de convaincre, ce qui est souvent contre-productif. Ce chapitre présente les deux types de rations non conventionnelles les plus communes, celles à base de viande crue et le sans céréales.
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To diagnose cutaneous adverse food reactions (CAFRs) in dogs and cats, dietary restriction-provocation trials are performed. Knowing the most common offending food allergens for these species would help determining the order of food challenges to optimize the time to diagnosis. The search for, and review and analysis of the best evidence available as of January 16, 2015 suggests that the most likely food allergens contributing to canine CAFRs are beef, dairy products, chicken, and wheat. The most common food allergens in cats are beef, fish and chicken. In dogs and cats, after a period of dietary restriction leading to the complete remission of clinical signs, food challenges to diagnose CAFR should begin with beef and dairy products, the most commonly recognized food allergens in these two species.
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We report feeding studies on adult domestic cats designed to disentangle the complex interactions among dietary protein, fat and carbohydrate in the control of intake. Using geometric techniques that combine mixture triangles and intake plots from the geometric framework, we: (1) demonstrate that cats balance their macronutrient intake, (2) estimate the composition of the target balance and (3) reveal the priorities given to different macronutrients under dietary conditions where the target is unachievable. Our analysis indicates that cats have a ceiling for carbohydrate intake, which limits ingestion and constrains them to deficits in protein and fat intake (relative to their target) on high-carbohydrate foods. Finally, we reanalyse data from a previous experiment that claimed that kittens failed to regulate protein intake, and show that, in fact, they did. These results not only add to the growing appreciation that carnivores, like herbivores and omnivores, regulate macronutrient intake, they also have important implications for designing feeding regimens for companion animals.
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1. Three experiments were conducted on the ability of cats to utilize dietary carbohydrates. In two experiments, the digestibilities of carbohydrates were measured by the chromic oxide-marker technique using a balanced Latin-Square allocation of treatments: in the third experiment, the effect of age and diet on the activity of intestinal β-galactosidase (lactase) ( EC 3.2.1.23) and β-fructofuranosidase (sucrase) ( EC 3.2.1.26) of kittens was measured. 2. In Expt 1 the digestibilities of six individual carbohydrates, glucose, sucrose, lactose, dextrin, raw maize starch and wood cellulose added to a meat-based basal diet were measured. 3. In Expt 2, a similar meat-based basal diet was used and the effect of three processing methods (fine and coarse grinding, and cooking) on the apparent digestibility of the starch in maize and wheat grain was measured. 4. In Expt 3 the effects of the inclusion of either 200 g lactose or 200 g sucrose/kg in an all-meat diet and of age on the β-galactosidase and β-fructofuranosidase activities of the small intestine of weanling kittens were measured. 5. Adult cats efficiently (> 0.94) digested all six individual carbohydrates added to the diet with the exception of cellulose, which was indigestible. The digestibility coefficients of glucose, sucrose and lactose were significantly ( P < 0.01) greater than that of starch. The inclusion of lactose caused diarrhoea in some cats and significantly ( P < 0.01) reduced apparent digestibility of crude protein (nitrogen × 6.25) in the total ration. 6. Fine grinding significantly enhanced the digestion of starch in wheat and maize grain, but the effect was greatest for maize grain. Cooking had a similar effect to fine grinding for wheat grain, but an effect intermediate between coarse and fine grinding for maize grain. 7. Intestinal β-galactosidase activity decreased with age in kittens (71-106 d). Neither β-fructofuranosidase nor β-galactosidase activities were significantly affected by the addition of sucrose and lactose to the all-meat diet.
Article
Objective: To determine total dietary fiber (TDF) composition of feline diets used for management of obesity and diabetes mellitus. Design: Cross-sectional survey. Sample: Dry veterinary (n = 10), canned veterinary (12), and canned over-the-counter (3) feline diets. Procedures: Percentage of TDF as insoluble dietary fiber (IDF), high-molecular-weight soluble dietary fiber (HMWSDF), and low-molecular-weight soluble dietary fiber (LMWSDF) was determined. Results: Median measured TDF concentration was greater than reported maximum crude fiber content in dry and canned diets. Median TDF (dry-matter) concentration in dry and canned diets was 12.2% (range, 8.11% to 27.16%) and 13.8% (range, 4.7% to 27.9%), respectively. Dry and canned diets, and diets with and without a source of oligosaccharides in the ingredient list, were not different in energy density or concentrations of TDF, IDF, HMWSDF, or LMWSDF. Similarly, loaf-type (n = 11) and gravy-type (4) canned diets differed only in LMWSDF concentration. Disparities in TDF concentrations among products existed despite a lack of differences among groups. Limited differences in TDF concentration and dietary fiber composition were detected when diets were compared on the basis of carbohydrate concentration. Diets labeled for management of obesity were higher in TDF concentration and lower in energy density than diets for management of diabetes mellitus. Conclusions and clinical relevance: Diets provided a range of TDF concentrations with variable concentrations of IDF, HMWSDF, and LMWSDF. Crude fiber concentration was not a reliable indicator of TDF concentration or dietary fiber composition. Because carbohydrate content is calculated as a difference, results suggested that use of crude fiber content would cause overestimation of both carbohydrate and energy content of diets.
Article
Reducing carbohydrate intake is recommended in diabetic cats and might also be useful in some healthy cats to decrease diabetes risk. To compare postprandial glucose and insulin concentrations and energy intakes between cats fed diets high in protein, fat, or carbohydrate. Twenty-four lean cats with normal glucose tolerance. In a prospective randomized study, each of 3 matched groups (n = 8) received a different test diet for 5 weeks. Diets were high in either protein (46% of metabolizable energy [ME]), fat (47% ME), or carbohydrate (47% ME). Glucose and insulin were measured during glucose tolerance, ad libitum, and meal-feeding tests. During ad libitum feeding, cats fed the high-carbohydrate diet consumed 25% and 18% more carbohydrate than cats fed diets high in fat and protein, respectively, and energy intake was highest when the high-fat and high-protein diets were fed. Regardless of the feeding pattern, cats fed the high-carbohydrate diet had 10-31% higher peak and mean glucose compared with both other diets; peak glucose in some cats reached 10.4 mmol/L (188 mg/dL) in cats fed 47% ME carbohydrate and 9.0 mmol/L (162 mg/dL) in cats fed 23% ME. High-carbohydrate diets increase postprandial glycemia in healthy cats compared with diets high in fat or protein, although energy intake is lower. Avoidance of high- and moderate-carbohydrate diets can be advantageous in cats at risk of diabetes. Maintenance energy requirements should be fed to prevent weight gain when switching to lower carbohydrate diets.
Article
A low-carbohydrate, high-protein (LCHP) diet is often recommended for the prevention and management of diabetes in cats; however, the effect of macronutrient composition on insulin sensitivity and energetic efficiency for weight gain is not known. The present study compared the effect in adult cats (n 32) of feeding a LCHP (23 and 47 % metabolisable energy (ME)) and a high-carbohydrate, low-protein (HCLP) diet (51 and 21 % ME) on fasting and postprandial glucose and insulin concentrations, and on insulin sensitivity. Tests were done in the 4th week of maintenance feeding and after 8 weeks of ad libitum feeding, when weight gain and energetic efficiency of each diet were also measured. When fed at maintenance energy, the HCLP diet resulted in higher postprandial glucose and insulin concentrations. When fed ad libitum, the LCHP diet resulted in greater weight gain (P < 0.01), and was associated with higher energetic efficiency. Overweight cats eating the LCHP diet had similar postprandial glucose concentrations to lean cats eating the HCLP diet. Insulin sensitivity was not different between the diets when cats were lean or overweight, but glucose effectiveness was higher after weight gain in cats fed the HCLP diet. According to the present results, LCHP diets fed at maintenance requirements might benefit cats with multiple risk factors for developing diabetes. However, ad libitum feeding of LCHP diets is not recommended as they have higher energetic efficiency and result in greater weight gain.
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From the foregoing discussion of the nutritional requirements and some of the metabolic anomalies of the cat, it is clear that the cat is adapted to eating a carnivorous diet. It may, however, have less capability than omnivores and herbivores to adapt to wide ranges in dietary composition. For example, the lack of ability to synthesize sufficient vitamin A from carotene, ornithine from glutamic acid, arachidonate from linoleate, and taurine from cysteine results from a complete deletion or severe limitation of the enzyme or pathway that makes each nutrient. Other nutrient requirements, such as the absolute requirement for niacin and the high protein requirement, appear to result from the high activity of one or more enzymes and the fact that these enzymes are not adaptive in the cat. For example, the cat cannot decrease picolinic carboxylase in order to force tryptophan toward the niacin-synthetic pathway (244) nor can it decrease the urea cycle enzymes when dietary protein is decreased in the diet in order to conserve nitrogen (209). Indeed, the cat appears to have less capability to adapt to most changes in dietary composition because it cannot change the quantities of enzymes involved in the metabolic pathways (209). This evolutionary development has resulted in more stringent nutritional requirements for cats than for omnivores such as the rat, dog, and man. What little evidence exists for other carnivore species leads us to suggest that this pattern may well be common among other strict carnivores. The metabolic differences between the cat and omnivores provide the researcher with a useful animal model for studying the biochemical basis of some nutrient requirements. For example, because there is no significant conversion of linoleate to arachidonate in cat liver (101, 150, 231), the physiological functions of linoleate can be determined independent of it having a role as a precursor of arachidonate (150). This has not been possible with other species. It is anticipated that further studies of the nutrition of the cat will increase our understanding of metabolic adaptation and nutrient functions.
Article
The objectives of this study were to investigate the prevalence of food sensitivity in cats with chronic idiopathic gastrointestinal problems, to identify the food ingredients responsible, and to characterize the clinical features. Seventy cats that presented for chronic gastrointestinal signs underwent diagnostic investigation. Fifty-five cats had idiopathic problems and were entered into the study. Diagnosis of food sensitivity was made by dietary elimination-challenge studies by using commercial selected-protein diets as the elimination diet. Sixteen (29%) of the 55 cats with chronic idiopathic gastrointestinal problems were diagnosed as food sensitive. The clinical signs of another 11 cats (20%) resolved on the elimination diet but did not recur after challenge with their previous diet. The foods or food ingredients responsible for the clinical signs were dietary staples. Fifty percent of affected cats were sensitive to more than 1 food ingredient. The clinical feature most suggestive of food sensitivity was concurrent occurrence of gastrointestinal and dermatological signs. Weight loss occurred in 11 of the affected cats, and large-bowel diarrhea was more common than small-bowel diarrhea. Assay of serum antigen-specific immunoglobulin E (IgE) had limited value as a screening test, and gastroscopic food sensitivity testing was not helpful. In conclusion, adverse reactions to dietary staples were common in this population of cats, and they responded well to selected-protein diets. Diagnosis requires dietary elimination-challenge trials and cannot be made on the basis of clinical signs, routine clinicopathological data, serum antigen-specific IgE assay, gastroscopic food sensitivity testing, or gastrointestinal biopsy.
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Plasma glucose and immunoreactive insulin (IRI) concentrations and activities of enzymes related to glucose metabolism in livers were measured in dogs and cats. Nucleotide sequences of the conserved region of glucokinase (GK) cDNA that contained ATP- and glucose-binding domains were determined in canine liver and feline pancreas for design of the species-specific oligonucleotide primers for reverse transcription-polymerase chain reaction (RT-PCR) analysis. There were no significant differences in plasma glucose and IRI concentrations between dogs and cats. In feline liver, although GK activities were not detected, activities of hexokinase, fructokinase, pyruvate kinase, glucose-6-phosphate dehydrogenase, fructose-1,6-bisphosphatase and glucose-6-phosphatase were significantly higher than those in canine liver. The partial sequences of canine liver GK and feline pancreas GK cDNA were respectively 88% and 89% identical with the rat liver GK cDNA. Expression of GK gene was observed in canine liver and pancreas and feline pancreas with RT-PCR using species specific primers based on the cDNA sequences.