ArticlePDF Available
JAVMA | DEC 1, 2018 | VOL 253 | NO. 11 1425
Trends in companion animal nutrition often mir-
ror trends in human nutrition, reflecting the
desire of pet owners to feed diets that they consid-
er healthy and beneficial for the well-being of their
pets.1–3 The number of people choosing to eat a plant-
based diet and adopting a vegan lifestyle has been
steadily increasing as individuals seek a lifestyle that
they perceive to be healthier and with less impact on
animals and the environment.4–6 It has been suggest-
ed that eliminating meat from the diet is more preva-
lent among pet owners than for the general public.7–9
Many of these meat-avoiding individuals have a moral
dilemma regarding the husbandry of carnivorous
pets: they avoid animal products in their own diet,
but they live with pets that rely on nutritional sus-
tenance from products derived from other animals.7
Interest in, and availability of, plant-based diets
are growing in popularity in the North American pet
food market,10,11 but there are little data to support
the benefits of feeding plant-based diets to omnivo-
rous and carnivorous pets. For dogs, most essential
nutrients can be obtained from plant sources.12 How-
ever, dogs evolved while eating an omnivorous diet
that was high in animal tissues,13 which leads to con-
cerns about whether plant-based diets can complete-
ly satisfy the nutritional requirements of dogs. Few
studies have been conducted to examine the nutri-
tional sufficiency of plant-based diets. Investigators of
published studies14 –17, a simply evaluated the content
of some nutrients in plant-based diets or evaluated a
limited number of health variables in dogs fed plant-
based diets.
The purpose of the information reported here
was to address nutrients of concern when formu-
lating plant-based diets and how to satisfy nutrient
Plant-based diets for dogs
Sarah A. S. Dodd bvsc, msc
Jennifer L. Adolphe phd
Adronie Verbrugghe dvm, phd
From the Department of Clinical Studies, Ontario Veterinary College, University of
Guelph, Guelph, ON N1G 2W0, Canada (Dodd, Verbrug ghe) ; and Petcurean, 435-
44550 S Sumas Rd, Chilliwack, BC V2R 5M3, Canada (Adolphe) .
Address correspondence to Dr. Verbrugghe (
requirements of dogs without the use of animal-
derived ingredients. It was intended to assist veteri-
narians when evaluating plant-based diets and pro-
viding guidance to pet owners who wish to feed their
dogs such diets.
Nutritional Requirements of Dogs
Domesticated dogs (Canis lupus familiaris) are
descended from wolves (Canis lupus) and have co-
existed with humans for 10,000 to 30,000 years.18,19
Dogs and wolves are both canids (family Canidae of
the order Carnivora).20 This taxonomic nomenclature
is misleading because the order Carnivora also con-
tains obligate carnivores such as the family Felidae
(eg, cats, cheetahs, and lions) and herbivores such
as the family Ailuropodidae (eg, pandas).19 The diet
of wolves can vary drastically, ranging from a diet
consisting almost completely of prey animals to one
containing up to 50% plant matter, which makes
them true omnivores or facultative carnivores.13,21,22
Wolves are naturally omnivorous in the wild, and the
domestication of dogs in coevolution with humans
has resulted in further evolutionary adaptation to di-
ets with a higher plant content.23 Ancestors of domes-
ticated dogs began to live in close association with
humans during the early agricultural revolution, and
they scavenged from refuse and waste near human
settlements. As humans adopted a less nomadic life-
style and began cultivating crops, their early dump
sites would have included food waste and feces rich
in starches.24 Indeed, differences in the genome of
domesticated dogs and wolves indicate that dog an-
cestors adapted from a mainly carnivorous diet to one
richer in starch as they began to rely on human settle-
ments as sources of nutrition.13,23
Current understanding of the nutritional require-
ments of dogs has been determined through decades
of research, such as studies and reports issued by the
National Research Council of the National Academies
of Sciences.25 On the basis of this information, nutri-
ent profiles published for use by the pet food industr y,
AA Amino acid
AAFCO Association of American Feed Control Officials
DHA Docosahexaenoic acid
FEDIAF European Pet Food Industry Federation
PUFA Polyunsaturated fatty acid
Timely Topics in Nutrition
In cooperation with
1426 JAVMA | DEC 1, 2018 | VOL 253 | NO. 11
such as those developed by the AAFCO26 and FEDI AF,27
are used to define the nutritional adequacy of pet di-
ets appropriate for various life stages. These life stages
include maintenance of adult dogs, growth of pup-
pies, and reproduction and lactation. In comparison
with maintenance requirements for adult dogs, pup-
pies have increased requirements for many nutrients
to support organ development, muscle synthesis, and
skeletal growth. Growing puppies are at greater risk
of nutritional insufficiencies than are adult dogs, and
appropriate nutrition is critical for healthy develop-
ment. In particular, puppies require higher concentra-
tions of dietar y fats, protein, and essential minerals as
well as provision of calcium and phosphorus within
a strict ratio.28 Inappropriate dietary management of
puppies, particularly those of large and giant breeds,
can result in irreversible deformities and compromise
quality of life.29 –32 It is likely more difficult to meet the
higher nutrient requirements of puppies, compared
with nutrient requirements of adult dogs, when feed-
ing a diet devoid of animal ingredients.
Nutrients of Concern
in Strictly Plant-Based Diets
Macronutrients and micronutrients
Essential macronutrients for dogs (ie, protein and
fat) can be found in both plant and animal ingredients.
However, micronutrients pose a greater challenge
when formulating a complete and balanced food for
dogs. No single ingredient, regardless of whether it is
of plant or animal origin, is replete in all the essential
nutrients in sufficient quantities or proportions. All
the essential nutrients can be obtained from nonani-
mal sources. Compared with animal-derived ingredi-
ents, plant-based ingredients may be scarce or poor
sources of some nutrients. As such, commercial dog
foods typically contain, at a minimum, additional vi-
tamins and minerals, which may be from synthetic or
plant-derived sources.
Of greatest concern for strictly plant-based diets
is the sufficiency of essential AAs and nutrients that
are primarily derived from animal ingredients. These
include lysine; the sulfur-containing AAs methionine,
cysteine, and taurine; the omega-3 PUFA DHA; and
vitamins A, B12, and D.12,15,33 Some minerals, namely
calcium, phosphorus, potassium, and zinc, are found
in low concentrations in most plant-based ingre-
dients12 ,15 and can be deficient in diets that are not
formulated or supplemented appropriately. However,
these minerals are available as supplement-type prod-
ucts from nonanimal sources. Both animal- and plant-
based diets often rely on supplementation of minerals
to be nutritionally complete and balanced. As long as
diets are supplemented with appropriate amounts of
minerals, the provision of adequate quantities of min-
erals without the use of animal products is not a con-
cern; thus, mineral supplementation of plant-based
diets will not be discussed further.
Most diets are also supplemented with vitamins.
Although nonanimal sources of most vitamins exist,
vitamins A, B12, and D are traditionally obtained from
animal sources.
Protein and essential AAs
Although protein can readily be found in many
plant ingredients, the protein content of strictly
plant-based diets should be closely monitored. Di-
etary protein provides both nonessential and essen-
tial AAs. Essential AAs cannot be synthesized within
the body and must be obtained from the diet in ad-
equate amounts to maintain life, promote healthy
growth, or support gestation and lactation. In com-
parison, nonessential AAs may be produced by the
body as required, provided adequate precursors are
available. Both nonessential and essential AAs may be
used to synthesize proteins within the body, act as
functional metabolites, or be catabolized as energy.
The essential AAs for dogs are arginine, histidine, iso-
leucine, leucine, lysine, methionine, phenylalanine,
threonine, tryptophan, and valine.25
The total quantity of protein in a diet is impor-
tant, but the quality or biological value of the pro-
tein must also be considered.34 The biological value
of protein is considered primarily to be a function
of digestibility and constituent AA content and de-
scribes the ability of the protein ingredient to provide
essential AAs to the subject consuming the diet.35
Other characteristics of an ingredient can affect the
biological value of protein, including the source and
processing practices. Animal tissues typically contain
proteins of high biological value; often all 10 essential
AAs are provided in sufficient quantities with high
digestibility. In contrast, the biological value of plant
proteins for pet foods has been questioned because
their AA profiles may be incomplete, particularly
with methionine or lysine being limiting AAs.12,15,17
When compared with animal-derived proteins, plant-
derived proteins may have lower digestibility because
of the presence of poorly digestible structural car-
bohydrates. In addition, plant-derived proteins may
require more processing to mitigate antinutritional
factors that impact palatability, digestibility, and uti-
lization of nutrients.34,36 However, a number of plant-
based protein ingredients have been proposed for
use in companion animal diets.36–38
Protein content differs among plant sources, al-
though some plant sources of protein contain total
protein and sulfur-containing AAs in quantities com-
parable to those of animal sources of protein com-
monly used in conventional pet foods39–4 8 ( Ta b l e
1). In addition to the essential AAs, taurine content
must also be considered in diets for dogs. Taurine, a
β-aminosulfonic acid, is not considered essential for
all dogs because it can be endogenously synthesized
when there are adequate amounts of sulfur-contain-
ing AAs in the diet.25–27 However, taurine may be con-
sidered conditionally essential in some circumstanc-
es, particularly for breeds that may be susceptible to
JAVMA | DEC 1, 2018 | VOL 253 | NO. 11 1427
taurine-deficient health conditions.49,50 Taurine is not
incorporated into protein in the body. Instead, it is
involved in fetal development, growth, neuromodula-
tion, vision, heart function, and antioxidation reac-
tions.25 Dogs have obligatory conjugation of bile acids
with taurine, which leads to high losses through fe-
cal excretion.4 9,50 This is exacerbated by diets high in
fermentable fiber, which may result in enhanced bile
acid excretion and microbial degradation of taurine-
conjugated bile acids.51 Dogs consuming plant-based
diets may be at increased risk of taurine deficiency be-
cause taurine is absent in plants other than algae, and
plant-based diets replete with protein may be margin-
al in precursor sulfur-containing AAs.25 Furthermore,
the high fiber content of most plant ingredients may
also increase taurine loss.52 Taurine deficiency may
manifest clinically as nonspecific signs (eg, lethargy
and anorexia) or as a more specific condition (dilated
cardiomyopathy).50 Therefore, it is crucial that plant-
based diets formulated for dogs contain sufficient
quantities of methionine and cysteine to support sul-
fur-containing AA metabolism as well as taurine syn-
thesis. To ensure adequate dietary intake of sulfur-
containing AAs with plant-based diets, the addition of
methionine and taurine is recommended. Nonanimal
sources of these nutrients are readily available, their
bioavailabilities have been determined, and they are
already used by animal feed industries.53,54
Few studies have been conducted to evaluate the
total protein or A A content (or both) of plant-based
dog foods. However, it has been found that diets
were replete and met industry requirements for those
nutrients.15, a Although single plant-derived ingredi-
ents do not provide proteins that meet all essential
AA requirements for dogs, complementary proteins
may be used to meet these requirements. By combin-
ing plant-derived proteins with complementary A A
profiles, a complete AA profile is created.55 Use of
complementary proteins can be illustrated by use of
the Liebig barrel (Figure 1).
Neither the total protein nor AA content is of
concern when a plant-based diet is appropriately for-
mulated, although the issue of digestibility of plant-
derived protein must be addressed. Plant-based diets
may have a higher fiber content than diets containing
animal ingredients, thus reducing both total digest-
ibility and protein digestibility.15,3 4 Soy, a common
plant protein source in pet foods, has total digest-
Table 1 Common sources of proteins for dog foods.
Sulfur-containing AAs
(g/100 g of product)*
Total protein
Source Product (g/100 g of product)* Methionine Cysteine Reference
Pearled barley 10 0.2 0.2 39
Chickpeas 17 0.2 0.2 40
Distillers’ grains 29 0.5 0.5 41
Germ meal 20 0.6 0.4 41
Gluten meal 60 1.9 1.1 41
Lentils 25 0.2 0.2 40
Groats 11 0.2 0.4 39
Flour 12 0 0 39
Protein concentrate 49 0.5 0.6 42
Whole dried 23 0.2 0.2 40
Meal 48 0.7 0.7 41
Protein concentrate 76 1.1 0.8 43
Whole beans 43 0.6 0.7 40
Sunflower meal 49 0.8 0.8 42
Brewer’s yeast 59 1.3 1.3 44
By-product meal 52 0.4 0.4 45
Lamb meal 59 0.8 0.8 46
Meat-and-bone meal 53 0.7 0.5 47
Blood meal 89 1.0 1.0 47
Chicken by-product meal 53 0.9 0.9 41
Chicken meal 66 1.0 1.7 46
Duck meal 61 1.2 0.6 46
Mechanically separated 15 0.3 0.1 48
chicken meat
Poultry by-product meal 69 0.8 0.5 45
Poultry meal 63 1.3 0.6 48
Venison meal 59 0.7 0.5 46
*As-fed basis.
1428 JAVMA | DEC 1, 2018 | VOL 253 | NO. 11
ibility that is demonstrably similar to that of animal
sources of protein.56–58 Rice and potato proteins,
canola, sunflower and peanut meals, and protein
fractions of low-fiber cereal products (eg, barley,
corn, flour, and wheat) are well digested by dogs.36,59
Protein-rich plant-based ingredients reportedly have
digestibility similar to that of animal-derived ingredi-
ents. However, the protein content, AA content, and
digestibility of commercial plant-based diets, with the
exception of 2 vegetarian therapeutic diets,b,c have
not been widely reported. Although the protein and
AA content of plant-based diets do not appear to be
adversely affected when animal-based ingredients are
not used, careful formulation is required to provide
complementary AAs to achieve an AA profile that
meets the nutritional requirements of dogs and en-
sures adequate quantities of essential AAs are avail-
able to the animals.
Fatty acids
Certain omega-3 and omega-6 PUFAs are essen-
tial fatty acids required by the body for critical cellu-
lar structure and physiologic functions.25,60 For adult
nonreproductive (males as well as females that are
not pregnant or lactating) dogs, α-linolenic acid is
the only essential omega-3 PUFA required to main-
tain health, and linoleic acid is the only essential
omega- 6 PU FA.25 Other longer-chain omega-3 PUFAs
(eicosapentaenoic acid and DHA) can be synthesized
in small but sufficient quantities from α-linolenic
acid and are not considered essential for adult non-
reproductive dogs. However, puppies require direct
provision of dietar y DHA during growth because
this essential PUFA selectively accumulates within
developing nervous tissues.61 Therefore, DHA must
be provided in diets formulated to support gestation,
lactation, and growth.25–27 Terrestrial plants can be
rich sources of α-linolenic acid, but they are not a
major source of DHA. Until recently, fish oil was the
only concentrated dietary source of DHA used com-
mercially.62 It is known that many species of algae
contain high amounts of DHA, and these ingredients
can be included in food formulations.63 Thus, plant-
based foods can be formulated to meet the essential
fatty acid requirements of dogs, even during gesta-
tion, lactation, and growth, through the inclusion of
marine plant products.
Vitamin A
Vitamin A (retinol) is a fat-soluble vitamin found
exclusively in animal tissues. It is essential for healthy
cell division and differentiation.64 Many plants con-
tain precursor provitamin A carotenoids that omniv-
orous animals such as dogs can metabolize to form
active vitamin A.65 On the other hand, obligate car-
nivores such as cats cannot use carotenoids and re-
quire dietary provision of preformed vitamin A.6 6, 67
Inclusion of vegetables rich in β-carotene can be used
Figure 1—Schematic depiction of complementary proteins by use of the Liebig barrel to demonstrate fulfillment of AA require-
ments. The barrel on the left depicts an incomplete protein profile, whereas the barrel on the right indicates the use of comple-
mentary proteins to form a complete AA profile. Arg = Arginine. His = Histidine. Ile = Isoleucine. Leu = Leucine. Lys = Lysine. Met
= Methionine. Phe = Phenylalanine. Thr = Threonine. Trp = Tryptophan. Val = Valine.
JAVMA | DEC 1, 2018 | VOL 253 | NO. 11 1429
to formulate canine diets that contain adequate pre-
cursors for vitamin A metabolism. Furthermore, syn-
thetic vitamin A analogs, in the form of retinyl esters,
can also be added to plant-based diets.64
Vitamin B12
The vitamin B complex includes a number of es-
sential nutrients, such as thiamine (vitamin B1), ribo-
flavin (vitamin B2), niacin (vitamin B3), pantothenic
acid (vitamin B5), pyridoxine (vitamin B6), biotin (vi-
tamin B7), folate (vitamin B9), and cobalamin (vitamin
B12). In general, the B vitamins are enzymatic cofac-
tors and precursors required for many metabolic pro-
cesses throughout the body.
Of the B vitamins, only cobalamin is not found
in plant materials. Cobalamin is produced only by
microbes in soil or fermented organic substances
and in specific parts of the gastrointestinal tract of
animals.25 In some animals, cobalamin is synthesized
by gastrointestinal microbes and is then absorbed
and distributed to the tissues, where it plays a role
as a cofactor in metabolic reactions. Thus, animal tis-
sues can be a rich source of vitamin B12. However, al-
though the gastrointestinal tract of dogs contains the
necessary flora for cobalamin synthesis, it occurs cau-
dal to the site of absorption and thus cannot be used
by canids. Therefore, dietary inclusion of cobalamin
is required.25 The dietary source of cobalamin in pet
foods has historically been from animal products, but
most commercial pet foods currently may also con-
tain bioavailable synthetically derived cobalamin pro-
duced from microbial fermentation.25 The addition of
synthetic cobalamin to plant-based diets thus fulfills
the dietary requirement for dogs.
Vitamin D
Vitamin D is the precursor to the hormone cal-
citriol, which critically influences calcium homeosta-
sis and bone metabolism.68 ,69 It is important to have
a sufficient amount of vitamin D for proper skeletal
mineralization, particularly in highly metabolically
active growing bones of juvenile dogs. Without pro-
vision of adequate vitamin D, dysfunction of bone
mineralization can occur despite meeting established
requirements for dietary calcium and phosphorus.69
There are 3 potential sources of vitamin D: di-
etary vitamin D as ergocalciferol (vitamin D2), di-
etary vitamin D as cholecalciferol (vitamin D3), and
endogenous synthesis in the skin when exposed to
UV light.70 Whereas most animals are capable of syn-
thesizing vitamin D in their skin with adequate expo-
sure to sunlight or UV radiation, dogs have high enzy-
matic catabolism of vitamin D precursors that results
in negligible conversion to vitamin D3.69,70 Thus, dogs
have a strict dietary requirement for vitamin D.
Differences in physiologic activity between vi-
tamin D2 and vitamin D3 have been documented in
other species, with most animals able to use vitamin
D3 with greater efficiency.25 For example, in both car-
nivorous cats and omnivorous humans, vitamin D2
was found to have less influence than vitamin D3 on
the concentration of the main vitamin D metabolite
calcidiol.71,72 ,d Dogs may be capable of using vitamin
D2 with an efficiency equal to cholecalciferol as a di-
etary source of vitamin D73,e; however, this finding
has not been confirmed, and recommendations for
the inclusion of vitamin D2 in diets formulated for
dogs currently do not exist.
The form of vitamin D is of paramount interest
when formulating plant-based diets because vitamin
D2 is derived from fungi and yeasts, whereas vitamin
D3 has traditionally been derived from animal prod-
ucts, particularly fish oils or sheep lanolin. However,
vitamin D3 has also been isolated from plants and is bi-
ologically active in animals.74,75 Plant tissue or cell cul-
tures from species of terrestrial flowering plants and
grasses from the Solanaceae, Cucurbitaceae, Fabaceae,
and Poaceae families as well as microalgae and lichens
may provide a source of plant-derived vitamin D3 for
fortification of plant-based pet foods.74 –76 A lthough
commercial preparations of plant-sourced vitamin D3
exist in the nutritional supplement market for humans,
such products do not appear to have been adopted for
use by the pet food industry. Thus, it would appear
that vitamin D may currently be the nutrient of most
concern in plant-based diets for dogs. A prudent rec-
ommendation to pet owners feeding their dogs a plant-
based diet may be to monitor serum calcidiol concen-
trations as an indication of vitamin D status.
Commercial Plant-Based
Diets for Dogs
In accordance with the current understanding
of pet nutrition, the importance of nutrients, not
ingredients, is emphasized. Thus, evaluation of the
nutritional sufficiency of a plant-based diet should
be based on the same criteria as diets that include
animal-derived ingredients. In North America, a diet
must be formulated to meet A AFCO nutrient recom-
mendations or pass a feeding trial conducted in accor-
dance with an A AFCO protocol for that diet to have
a statement indicating it is complete and balanced
for a given life stage.26 Many consider feeding trials
to be superior to simply being formulated to meet a
specific nutrient profile because nutrient bioavailabil-
ity may be affected by processing and the nutritional
content of a consumed diet may differ from the ex-
pected nutritional profile of a diet formulation.56
A large criticism of plant-based diets is that there
is little evidence to substantiate claims of nutritional
sufficiency because, to the authors’ knowledge, no
plant-based diets have been evaluated in a feeding
trial conducted in accordance with an AAFCO proto-
col. However, this is not a criticism exclusive to plant-
based diets. As revealed by the nutrition statement on
the packaging, most of the diets sold by the top com-
mercial manufacturers are formulated to meet the
AAFCO requirements of the specific life stage of ani-
mals but have not been evaluated via feeding trials.
1430 JAVMA | DEC 1, 2018 | VOL 253 | NO. 11
Furthermore, feeding trials performed in accordance
with AAFCO protocols require only a small sample
size, a short duration, and few outcome measures that
strongly correlate with nutritional adequacy.26
Although a feeding trial may be used to sub-
stantiate claims of nutritional adequacy, it is by no
means widely adopted throughout the industry. For
diets that have been formulated to a specific nutrient
profile but that have not been substantiated with a
feeding trial, additional evidence to support the nutri-
tional statement may be achieved through testing of
the final product (eg, dietary nutrient analysis and di-
gestibility testing; Supplementary Table S1, avail-
able at
javma.253.11.1425). Companies do not typically in-
clude this information on dog food packaging or on
their websites. Therefore, interested veterinarians
and pet owners are encouraged to contact companies
to discuss the qualifications and credentials of the
diet formulator, quality assurance and quality control
measures for diet manufacturing, and types of tests
performed on the finished product.77
Home-prepared Plant-Based
Diets for Dogs
Since the concept of complete and balanced diets
was introduced into the pet food industry nearly 50
years ago, the practice of feeding commercial diets
has commonly been the main method of feeding pet
dogs.78,79 However, trends in companion animal nu-
trition often mirror trends in human nutrition, and a
growing number of pet owners currently appear to
prefer home-prepared diets over processed commer-
cial diets for their dogs.80,f Home-prepared diets are
recognized as being at high risk for nutritional imbal-
ances and insufficiencies when not properly formu-
lated, and feeding such diets may result in adverse
health effects.3,81,82 Whereas home-prepared diets
made with animal ingredients are often nutritionally
imbalanced and insufficient in some nutrients, par-
ticularly vitamins and minerals, they may be replete
in protein and AAs because they contain complete
protein sources.83,84 Considering the aforementioned
challenges regarding essential nutrients found primar-
ily in animal ingredients, home-prepared plant-based
diets are at least as likely to have vitamin and min-
eral imbalances and insufficiencies as home-prepared
animal-based diets. In addition, they are also likely to
be insufficient in sulfur-containing AAs and may not
provide adequate amounts of total protein. From an
infectious disease perspective, home-prepared plant-
based diets do have an advantage over raw home-pre-
pared animal-based diets in that there is an absence
of uncooked meat with associated pathogenic organ-
isms and the potential for infectious disease and anti-
microbial resistance.85–87
It is challenging to properly formulate home-
prepared diets, and a plant-based home-prepared diet
should be fed to a dog only when the diet has been
formulated by an experienced veterinary or animal
nutritionist. The veterinary literature contains nu-
merous examples of adverse health outcomes associ-
ated with improperly formulated home-prepared di-
ets,29,31,32,88 and pet owners are advised to scrutinize
the formulators of home-prepared diets and commer-
cial pet foods with the same standards.77 Thus, it is
recommended that all dogs fed a home-prepared diet,
regardless of ingredients, be considered high-risk pa-
tients and be examined by a veterinarian at least bian-
nually to monitor health and wellness.3 Veterinarians
can quickly assess the suitability of a home-prepared
diet using resources such as checklists to identify
likely nutritional inadequacies.37 When it appears that
a diet is unlikely to meet the nutritional requirements
of the pet to which it is being fed, veterinarians are
encouraged to advise pet owners to transition their
pets to a suitable commercial diet, which may be de-
termined by use of World Small Animal Veterinary As-
sociation recommendations.77 Alternatively, pet own-
ers may be referred to a veterinarian who is board
certified in veterinary nutritiong,h for evaluation of
the diet.
Clinical Summary
Dogs have dietary requirements for energy and
essential nutrients, but they do not have a recognized
requirement for animal-derived ingredients per se. In
accordance with the current understanding of pet nu-
trition, any diet that meets or exceeds the minimum
nutrient requirements of a dog for a specific life stage
would be considered nutritionally sufficient for that
animal, regardless of ingredients. However, special
care must be taken when formulating plant-based di-
ets to ensure that all nutrient requirements are met,
particularly requirements for concentrations of total
protein, methionine, taurine, DHA, and vitamins A,
B12, and D because these nutrients are typically ob-
tained from animal-based ingredients. An additional
consideration for dogs fed plant-based diets may be
to evaluate vitamin D status to ensure the dietary
ergocalciferol content is adequate to maintain se-
rum 25-hydroxyvitamin D concentrations. Dogs fed
home-prepared plant-based diets are at similar risk of
nutrient imbalances and deficiencies as dogs fed any
other home-prepared diets. Thus, it is recommended
that a pet owner who wants to feed a home-prepared
plant-based diet use a recipe formulated by a quali-
fied veterinary or animal nutritionist and that dogs
fed a home-prepared diet be considered as high-risk
animals and be routinely examined by a veterinarian.
Financial support for Dr. Dodd was provided by a Mitacs
Accelerate gr ant in partnership with Petcurean Pet Nutrition.
Dr. Dodd has received grants in association with pet food com -
panies that produce or distribute plant-based dog foods and has en-
gaged in paid industry internsh ips. Dr. Adolphe is a paid employee
of PPN Limited Partnership (Petcurean). Dr. Verbrugghe is the
Royal Canin Veterinary Diets Endowed Chair in Canine and Feli ne
Clinical Nutrition at the Ontario Veterinar y College.
JAVMA | DEC 1, 2018 | VOL 253 | NO. 11 1431
a. Semp PH. Vegan nutrition of dogs and cats. Master’s thesis,
Veterinary University of Vienna, Vienna, Austria, 2014.
b. Vegetarian, Royal Canin, St Charles, Mo.
c. H A-Hypoallergenic, Nestlé Purina PetCare Co, St Louis, Mo.
d. Delaney SJ. Serum ionized calcium, 25-hydroxy vitamin D,
and parathyroid hormone in two dogs fed a homemade diet
fortified with vitamin D2 (abstr). J Anim Physiol Anim Nutr
2015;9 9: 818–819.
e. Wilson L, Tripkovic L, Hart K, et al. Mechanisms for differ-
ences in the efficacy of vitamin D2 and vitamin D3: assess-
ment of post-supplementation decline i n vitamin D status in
the D2-D3 study (abstr), in Proceedings. Annu Conf Nutr Soc
2016 ;75:E116.
f. Dodd SAS, Cave NJ, Adolphe JL, et al. Changes in pet feeding
practices over the past decade (abstr), in Proceedings. Am
Coll Vet Intern Med Forum 2018;894.
g. Directory of Diplomates of the American College of Vet-
erinary Nutrition. Available at:
Accessed Jun 6, 2018.
h. Directory of Diplomates of the European College of Veterinary
and Comparative Nutrition. Available at:
find-a-specialist?collegeId=407&countr yId= 0 &specialistTitle
Id=14. Accessed Jun 6, 2018.
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... Introduction Diets composed of plant-based (PB) foods and devoid of animal products are receiving growing attention across the food chain [1,2]. Interest in extruded PB diets for pets is suspected to be due, in part, to the body of evidence in people demonstrating several health-promoting effects of PB diets. ...
... Certain PB foods (e.g., rice, corn) serve as functional ingredients in the extrusion process in that they influence shape, texture, and expansion of kibble. The nutritive content and digestibility of PB ingredients commonly used in commercial pet foods have been studied extensively [9][10][11][12][13], and it is wellestablished that PB ingredients can serve as viable sources of energy, dietary fiber, digestible carbohydrates, and a variety of other essential and non-essential nutrients for dogs [2,14]. In recent years, consumer demand for alternative protein sources has prompted researchers to investigate amino acid (AA) digestibility and protein quality of several PB ingredients, such as pulses (e.g., beans, lentils), protein concentrates (e.g., pea protein, potato protein), and soy [15][16][17][18]. ...
Full-text available
Consumer demand for commercially prepared plant-based (PB) dog food is increasing, but studies evaluating the short- or long-term effects of PB diets on canine health are lacking. The objective of this study was to assess the short-term amino acid (AA), clinicopathologic, and echocardiographic findings in 34 client-owned dogs fed a commercial extruded plant-based diet (PBD) in which pea protein was the primary protein source and 4 control dogs fed a commercial extruded traditional diet (TD). Plasma AA and whole blood taurine concentrations were measured in dogs at baseline and after 4 weeks on the PBD or the TD. Hematologic, serum biochemical, and echocardiographic testing were performed at baseline and after 12 weeks on the PBD or the TD. Four dogs in the PBD group did not complete the study. All essential AAs, except methionine, were higher in dogs after 4 weeks on the PBD compared to baseline. Taurine (plasma and whole blood) was also higher after 4 weeks on the PBD compared to baseline. A meaningful difference was detected in whole blood taurine between the PBD group and the control group at 4 weeks (P = .026) with the PBD group being higher. Median hematologic and biochemical results for the PBD group were within normal limits at baseline and at 12 weeks. In the PBD group, left ventricular internal diastolic dimension (LVIDd, P = < .001) and normalized LVIDd (P = .031) were higher 12 weeks post-PBD compared to baseline. There were no meaningful differences in left ventricular internal systolic dimension (LVIDs), normalized LVIDs, or fractional shortening 12 weeks post-PBD. There was no statistical evidence of difference between the 2 groups of dogs for any of the echocardiographic parameters at baseline or at 12 weeks. Essential AA or taurine deficiency was not observed in this cohort of dogs fed a commercial extruded PBD. Additionally, clinically relevant hematologic, serum biochemical and echocardiographic alterations were not detected. Further research is required to determine if long-term static feeding of PB diets can meet and maintain AA and other nutrient targets in dogs.
... Animal tissues typically contain high biological value proteins; often, all 10 essential amino acids AAs are provided in sufficient quantities with high digestibility. In contrast, the biological value of plant proteins for pet foods has been questioned because their AA profiles may be incomplete, particularly with methionine or lysine limiting amino acids (Dodd et al., 2018). To reduce the risk of such deficiencies, synthetic amino acids are added to conventional plantbased pet foods but not organic ones. ...
Technical Report
Full-text available
Assessment of products and substances used in organic production
... Accordingly, interest in alternative diets-including vegetarian diets-is likely to grow. It is absolutely possible for companion animals to survive, and indeed thrive, on vegetarian diets [2,[56][57][58][59][60] The data of this study appear to indicate that virtually the only significant difference between the meatbased diet and vegetarian diet was lower nitrogen-free extract digestibility in the vegetarian diet. However, there was no significant difference in amount of nitrogen excreted in feces or in the fecal scores. ...
Full-text available
Pet owners are increasingly concerned about the links between health status, animal welfare, environmental impacts, climate change and consumption of animal products. Accordingly, many owners are increasingly interested in vegetarian diets for themselves and their companion animals. However, such diets should be investigated nutritionally regards digestibility as well as on fecal quality and nitrogen output. In light of this trend, six Beagle dogs were included in a cross-over experimental design and offered a vegetarian diet containing wheat gluten (8.81%), rice protein (8.81%) and sunflower oil (6.84%) or an meat-based diet containing poultry meal (19.5%) and poultry fat (5.23%). The dogs received extruded complete diets for 12 days (adaptation and collection period, each 6 days). The dogs fed both diets showed a high and identical palatability (scoring of food intake) of the experimental diets. No significant differences occurred regarding digestibility of organic matter, crude protein and crude fat between vegetarian and meat-based diets. However, dogs fed the meat-based diet had higher (p < 0.05) nitrogen-free extract digestibility (89.5%) compared to those fed the vegetarian diet (88.6%). The amount of nitrogen excreted in feces (g)/kg BW 0.75 was slightly, but not significantly, higher for dogs fed the vegetarian diet compared to those fed the meat-based diet (0.88 vs 0.79). The fecal consistency scores were considered to be within an acceptable range (well formed and firm). The mass of the feces between both groups were similar (62.9 g wet feces/100 g dry matter food) for vegetarian and meat-based diets. Additionally, the fecal dry matter content was comparable between both groups (29.0% and 29.6% for vegetarian and meat-based diets, respectively). In conclusion, the results of this study appear to indicate that virtually the only significant difference between the two diets was lower nitrogen-free extract digestibility in the vegetarian diet. However, the vegetarian diet did not result in a significant difference in amount of nitrogen excreted in feces.
... With respect to the most common nutrient insufficiencies detected, those being sulfur amino acids, taurine, arachidonic acid, EPA + DHA, calcium, phosphorus and vitamin D, correction of the insufficiencies would be expected to be relatively simple [40] (Table 6). ...
Full-text available
Plant-based foods intended for feeding dogs and cats are available in Canada, though few studies have examined the suitability of plant-based foods for dogs and cats. All commercial plant-based extruded and wet pet food products available in Ontario, Canada, in 2018 (n = 26) were acquired and analysed for energy, crude protein, crude fat, crude fibre, ash, amino acids, fatty acids, minerals and vitamins A, B12, D2 and D3. Results were compared with recommendations of the Association of American Feed Control Officials (AAFCO) and the European Pet Food Industry Federation (FEDIAF). Thirteen products were labelled for adult canine maintenance, four for canine all life stages, one for puppy growth, two for adult feline maintenance, three for feline all life stages, one for adult maintenance of dogs and cats and two for all life stages of dogs and cats. Four products met AAFCO and one product met FEDIAF nutrient recommendations for canine maintenance. No diets met AAFCO or FEDIAF recommendations for feline maintenance or growth for either species. Nutrients most commonly found insufficient were: sulfur amino acids, taurine, arachidonic acid, EPA and DHA, calcium phosphorus and vitamin D. There were no nutrients unable to be provided from non-animal sources. Compliance with labelling guidelines was also poor, similar to other findings with commercial animal-based pet products. The results from this study indicate areas where producers of plant-based pet foods must improve to meet the industry recommended nutrient profiles and labelling requirements.
... It also bears pointing out that the numbers in both studies were very low (representing less than 100 DCM-affected dogs between them), A c c e p t e d M a n u s c r i p t 15 of 28 which surely represents a fraction of the dogs consuming grain-free, pulse-based diets. A recent thoughtful review supports these conclusions by reiterating the crucial need for plant-based diets for dogs to be formulated with sufficient quantities of bioavailable methionine and cysteine to support adequate taurine synthesis (Dodd et al., 2018). This can be achieved with the addition of purified amino acids and other sources that are readily available (Gloaguen et al., 2014). ...
Full-text available
In July 2018, the Food and Drug Administration (FDA) warned about a possible relationship between dilated cardiomyopathy (DCM) in dogs and the consumption of dog food formulated with potatoes and pulse ingredients. This issue may impede utilization of pulse ingredients in dog food or consideration of alternative proteins. Pulse ingredients have been used in the pet food industry for over 2 decades and represent a valuable source of protein to compliment animal-based ingredients. Moreover, individual ingredients used in commercial foods do not represent the final nutrient concentration of the complete diet. Thus, nutritionists formulating dog food must balance complementary ingredients to fulfill the animal’s nutrient needs in the final diet. There are multiple factors that should be considered, including differences in nutrient digestibility and overall bioavailability, the fermentability and quantity of fiber, and interactions among food constituents that can increase the risk of DCM development. Taurine is a dispensable amino acid that has been linked to DCM in dogs. As such, adequate supply of taurine and/or precursors for taurine synthesis play an important role in preventing DCM. However, requirements of amino acids in dogs are not well investigated and are presented in total dietary content basis which does not account for bioavailability or digestibility. Similarly, any nutrient (e.g. soluble and fermentable fiber) or physiological condition (e.g. size of the dog, sex, age) that increases the requirement for taurine will also augment the possibility for DCM development. Dog food formulators should have a deep knowledge of processing methodologies and nutrient interactions beyond meeting AAFCO nutrient profiles and should not carelessly follow unsubstantiated market trends. Vegetable ingredients, including pulses, are nutritious and can be used in combination with complementary ingredients to meet the nutritional needs of the dog.
Full-text available
Background Some dog owners elect to feed their dog a plant-based food either as part of or for their entire dietary intake. Being omnivores or facultative carnivores, a strictly plant-based diet is not the natural type of food dogs evolved to consume, leaving some question as to whether this feeding management strategy is safe and healthy for dogs. Objectives This study surveyed owner perceptions of health and wellbeing of dogs and compared between those fed meat-based and plant-based diets. Methods A web-based questionnaire was distributed to pet owners to collect data on dog characteristics, husbandry, health and wellbeing. Univariate comparisons between diet groups was made by chi square analyses or Kaplan-Meier tests as appropriate, with a significance cut-off value of 0.05. Multivariate models were negative binomial and logistic regression for count and categorical data, respectively. Results Owners feeding plant-based diets to their dog reported fewer health disorders, specifically with respect to ocular or gastrointestinal and hepatic disorders. Dog longevity was reported to be greater for dogs fed plant-based diets. Owners feeding plant-based diets to their dogs relied less on veterinary associates for nutrition information, versus dog owners feeding meat-based diets. Conclusions Dog owners feeding a plant-based diet did not perceive adverse health effects in their dogs. The results might suggest an association between feeding a plant-based diet and perceived health and longevity, however inherent bias and limitations associated with surveys of owner perception must be considered, and objective research is required to determine if plant-based diets truly affect canine health.
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Consumer suspicion of conventional pet foods, along with perceived health benefits of alternative diets, are fuelling development of the latter. These include raw meat diets, in vitro meat products, and diets based on novel protein sources such as terrestrial and marine plants, insects, yeast and fungi. However, some claim vegan diets may be less palatable, or may compromise animal welfare. We surveyed 4,060 dog or cat guardians to determine the importance to them of pet food palatability, and the degree to which their animals displayed specific behavioural indicators of palatability at meal times. Guardians were asked to choose one dog or cat that had been within their household for at least one year, and not on a prescription or therapeutic diet. Of 3,976 respondents who played some role in pet diet decision-making, palatability was the third most important among 12 factors cited as important when choosing pet diets. For 1,585 respondents feeding conventional or raw meat diets, who stated they would realistically consider alternative diets, palatability was the fourth most important among 14 desired attributes. For the 2,308 dogs included, reported observations of 10 behavioural indicators of palatability at meal times reliably indicated significant effects of increased reports of appetitive behaviour by dogs on a raw meat diet, as opposed to a conventional diet. There was no consistent evidence of a difference between vegan diets and either the conventional or raw meat diets. For the 1,135 cats included, reported observations of 15 behavioural indicators indicated that diet made little difference to food-oriented behaviour. Based on these owner-reported behaviours, our results indicate that vegan pet foods are generally at least as palatable to dogs and cats as conventional meat or raw meat diets, and do not compromise their welfare, when other welfare determinants, such as nutritional requirements, are adequately provided.
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Background Pet owners have many feeding options, some may be considered unconventional by veterinary practitioners. Provision of appropriate nutrition is a basic requirement, with adverse health outcomes possible when a pet diet is inadequate. Objective To capture dog and cat feeding practices, with a special focus on countries with large English-speaking populations, and to compare with data published over the previous 10 years. Methods An electronic questionnaire was provided for dog and cat owners online. Responses were analysed using descriptive statistics, and comparisons made with data from nine peer-reviewed articles published over the previous 10 years. Results Responses from 3673 English-speaking dog and cat owners in Australia, Canada, New Zealand, the UK and the USA were included. In previous publications, conventional (commercial, heat-processed) products were the predominant method of feeding. In recent publications, feeding unconventional (raw, homemade, vegetarian) diets appeared more prevalent. In the present study, most (79 per cent dogs, 90 per cent cats) pets were offered conventional food. However a few (13 per cent dogs, 32 per cent cats) pets were fed conventional foods exclusively. Many pets were offered homemade (64 per cent dogs, 46 per cent cats) and/or raw (66 per cent dogs, 53 per cent cats) foods. Different feeding practices were associated with geographical location. Conclusion As an increased risk of nutrient insufficiency and associated conditions have been attributed to unconventional feeding practices, veterinarians must be aware of pet feeding trends and educate clients about the nutritional needs of companion animals.
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People who avoid eating animals tend to share their homes with animal companions, and moral dilemma may arise when they are faced with feeding animal products to their omnivorous dogs and carnivorous cats. One option to alleviate this conflict is to feed pets a diet devoid of animal ingredients—a ‘plant-based’ or ‘vegan’ diet. The number of pet owners who avoid animal products, either in their own or in their pets’ diet, is not currently known. The objective of this study was to estimate the number of meat-avoiding pet owners, identify concerns regarding conventional animal- and plant-based pet food, and estimate the number of pets fed a plant-based diet. A questionnaire was disseminated online to English-speaking pet owners (n = 3,673) to collect data regarding pet owner demographics, diet, pet type, pet diet, and concerns regarding pet foods. Results found that pet owners were more likely to be vegetarian (6.2%; 229/3,673) or vegan (5.8%; 212/3,673) than previously reported for members of the general population. With the exception of one dog owned by a vegetarian, vegans were the only pet owners who fed plant-based diets to their pets (1.6%; 59/3,673). Of the pet owners who did not currently feed plant-based diets but expressed interest in doing so, a large proportion (45%; 269/599) desired more information demonstrating the nutritional adequacy of plant-based diets. Amongst all pet owners, the concern most commonly reported regarding meat-based pet foods was for the welfare of farm animals (39%; 1,275/3,231). The most common concern regarding strictly plant-based pet foods was regarding the nutritional completeness of the diet (74%; 2,439/3,318). Amongst vegans, factors which predicted the feeding of plant-based diets to their pets were concern regarding the cost of plant-based diets, a lack of concern regarding plant-based diets being unnatural, and reporting no concern at all regarding plant-based diets for pets. Given these findings, further research is warranted to investigate plant-based nutrition for domestic dogs and cats.
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Background The practice of feeding of diets containing raw animal products (RAP) to pets (dogs and cats) is discouraged by veterinary organizations and governmental public health organizations. Nevertheless, the practice of feeding RAP to pets is increasing in popularity. Pet owner motivations for feeding RAP diets to pets have not been explored and the benefits of RAP diets remain largely anecdotal. We hypothesized that pet owners feeding RAP diets would not rely on veterinary advice in choosing their pet’s diet. We also hypothesized that these owners would have lower levels of trust in veterinary advice with respect to nutrition relative to pet owners not feeding RAP. Methods An anonymous web-based survey was developed to identify pet owner motivations for feeding RAP diets, and to characterize the veterinarian-client relationships of individuals feeding RAP diets. Results There were 2,337 respondents and 2,171 completed surveys. Of survey respondents, 804 reported feeding RAP at the time of the survey. While 20% of pet owners feeding RAP relied on online resources to determine what or how much RAP to feed, only 9% reported consulting with a veterinarian in making decisions about feeding RAP. Pet owners feeding RAP reported lower levels of trust in veterinary advice both ‘in general’ and ‘with respect to nutrition’ than pet owners not feeding RAP. Most pet owners reported that a discussion regarding their pet’s nutrition does not occur at every veterinary appointment. Discussion Pet owners feeding a RAP diet have lower trust in veterinary advice than pet owners not feeding a RAP diet. Owners feeding RAP are more reliant on online resources than their own veterinarian in deciding what and how much RAP to feed. Pet owners perceive that nutrition is not discussed at most veterinary appointments. Therefore, there is room for improvement in the veterinarian-client communication with regards to nutrition.
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Companion animal owners are increasingly concerned about the links between degenerative health conditions, farm animal welfare problems, environmental degradation, fertilizers and herbicides, climate change, and causative factors; such as animal farming and the consumption of animal products. Accordingly, many owners are increasingly interested in vegetarian diets for themselves and their companion animals. However, are vegetarian canine and feline diets nutritious and safe? Four studies assessing the nutritional soundness of these diets were reviewed, and manufacturer responses to the most recent studies are provided. Additional reviewed studies examined the nutritional soundness of commercial meat-based diets and the health status of cats and dogs maintained on vegetarian and meat-based diets. Problems with all of these dietary choices have been documented, including nutritional inadequacies and health problems. However, a significant and growing body of population studies and case reports have indicated that cats and dogs maintained on vegetarian diets may be healthy-including those exercising at the highest levels-and, indeed, may experience a range of health benefits. Such diets must be nutritionally complete and reasonably balanced, however, and owners should regularly monitor urinary acidity and should correct urinary alkalinisation through appropriate dietary additives, if necessary.
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Predation by large carnivores is a dominant factor shaping wildlife communities and an understanding of local foraging strategies of predators is central to the management of wildlife populations. Information on local foraging strategies is particularly important where carnivores might exploit alternate resources that could influence predator–prey interactions, carnivore population dynamics, and a variety of interactions at lower trophic levels. We used carbon (δ¹³C) and nitrogen (δ¹⁵N) values in serially sampled wolf (Canis lupus) vibrissae to quantify relative resource use and dietary variation among wolves (n = 115) from 4 areas in southwestern Alaska that differed in the availability of terrestrial and marine resources. Mean vibrissae isotope values varied by ~8‰ for δ¹³C and ~12‰ for δ¹⁵N and showed high levels of spatial, seasonal, and individual variation. While results showed that ungulates were the principal prey for wolves in all 4 areas, wolves also exploited a variety of alternate marine resources that represented an important component of wolf diets in some areas. Estimated dietary contributions from marine resources ranged from 28% to 56% among areas and use of these resources varied both spatially and seasonally. Dietary variation and use of marine resources increased from northeast to southwest along the Alaska Peninsula with increasing access to coastal areas and decreasing ungulate abundance. Seasonal shifts in resource use were also evident with dietary variation being highest during summer and fall when wolves consumed more alternate resources than during winter. Our findings suggest that use of marine resources and local variation in foraging strategies of wolves might, through a variety of pathways, have broad implications for the management of wolf–ungulate communities in southwestern Alaska.
Legumes consumption is a usual and beneficial part of the human diet and contributing to health. Moreover, it is presently taking place a re-evaluation for its useful effects of consumption in the diet, which is the basis for various health claims. They are essential source of protein, carbohydrates, dietary fibre, micronutrients and various phytochemicals. Legumes have appreciable quantity of all the essential amino acids excluding sulphur containing amino acids, which can be balanced to combine with cereals in daily intake. Starch is the major stored carbohydrate followed by dietary fibre, simple sugars and oligosaccharides. Calcium, magnesium, potassium, phosphorus and iron are also present in legume seeds. Bioavailability of nutrients can be increased by soaking, sprouting and fermentation. Consumption of legumes reduces the risk of cardiovascular disease, some cancers (colon, breast and prostate) and also helps to manage body weight due to its satiety value. FAO has chosen 2016 as the International Year of Pulses which will emphasize the health and environmental benefits of pulses. Nutritional composition, anti-nutritional factors and health benefits of legumes are summarised in the current review.
A 6-month-old intact female giant schnauzer dog fed a nutritionally unbalanced homemade diet was evaluated because of a 1-month history of lameness and difficulty walking. Abnormalities identified on ancillary tests, in conjunction with the dog's clinical improvement following diet change, suggested a diagnosis of vitamin D deficiency and nutritional secondary hyperparathyroidism. This report underlines the importance of appropriate feeding management, especially during the vulnerable growth phase.
According to various surveys, the proportion of people following a vegan diet, i.e. people foregoing not only meat and fish but all products of animal origin, has increased in Germany in recent years. This article illustrates the initial descriptive results of a German quantitative sociological study, in which only vegans were questioned via an online survey. The three most important motives for following a vegan diet are reports on factory farming, climate protection and health. Most respondents believe that it is now easier to follow a vegan diet than in the past. More than a third of respondents had followed a vegan diet for more than two years.
Protein quality was evaluated for mechanically separated chicken meat (MSC) and salmon protein hydrolysate (SPH), and for extruded dog foods where MSC or SPH partially replaced poultry meal (PM). Apparent total tract digestibility (ATTD) of crude protein (CP) and amino acids (AA) in the protein ingredients and extruded foods was determined with mink (Neovison vison). The extruded dog foods included a control diet with protein from PM and grain, and two diets where MSC or SPH provided 25% of the dietary CP. Nutrient composition of the protein ingredients varied, dry matter (DM) was 944.0, 358.0 and 597.4 g/kg, CP was 670.7, 421.2 and 868.9 g/kg DM, crude fat was 141.4, 547.8 and 18.5 g/kg DM and ash was 126.4, 32.1 and 107.0 g/kg DM for PM, MSC and SPH respectively. The content of essential AA (g/100 g CP) was more than 10.0 percentage units lower in SPH than in PM and MSC. The ATTD of CP differed (p < 0.001) between protein ingredients and was 80.9%, 88.2% and 91.3% for PM, MSC and SPH respectively. The ATTD of total AA was lowest (p < 0.001) for PM, and similar (p > 0.05) for MSC and SPH. In the extruded diets, the expected higher ATTD of CP and AA from replacement of PM with MSC or SPH was not observed. The ATTD of CP was determined to be 80.3%, 81.3% and 79.0% for the PM, MSC and SPH extruded foods respectively. Furthermore, the ATTD of several AA was numerically highest for the PM diet. Possibly, extrusion affected ATTD of the diets differently due to different properties and previous processing of the three protein ingredients.
Amino acids are the second most expensive nutrients in practical pig and poultry diets after energy. High protein sunflower meal (HiPSF) and pea protein isolate (PPI) are potential alternative protein sources for soybean meal and there is a great interest to explore their utilization as dietary ingredients for swine. Thus, eight ileal-cannulated barrows (initial BW = 23.5 ± 0.9 kg) were used to determine the apparent (AID) and standardized (SID) ileal amino acid (AA) digestibilities in HiPSF and PPI with or without multi-carbohydrase enzyme (MC) supplementation. Pigs were randomly assigned to 1 of 5 treatments in a replicated 4 × 5 incomplete Latin square design to give 8 observations per treatment. The experimental diets consisted of HiPSF or PPI as the sole source of protein with or without MC and a low-protein diet (5% casein) used to quantify endogenous AA losses. All diets contained titanium dioxide (0.3%) as an indigestible marker. Pigs were given their daily feed allowance at a rate of 4.5% of BW determined at the beginning of each experimental period. Each experimental period lasted for 7 d and the ileal digesta were collected on d 6 and 7. In general, AA digestibilities were higher in PPI than in HiPSF, with the exception of Met and Cys. There was no effect of MC on AA digestibility except for Lys, Ala, Cys and Pro in PPI. The AID and SID of essential AA in HiPSF and PPI (without MC) were, respectively: Arg, 0.86, 0.90 and 0.92, 0.95; His, 0.45, 0.54 and 0.58, 0.67; Ile, 0.78, 0.83 and 0.86, 0.90; Leu, 0.77, 0.81 and 0.86, 0.90; Lys, 0.71, 0.77 and 0.89, 0.92; Met, 0.85, 0.88 and 0.84, 0.87; Phe, 0.79, 0.82 and 0.86, 0.88; Thr, 0.68, 0.77 and 0.77, 0.85; Val, 0.75, 0.80 and 0.82, 0.87. The MC increased (P < 0.05) the AID of Lys (0.89 vs 0.91), Cys (0.59 vs 0.62) and Pro (0.79 vs 0.85) and SID of Lys (0.92 vs 0.94), Ala (0.88 vs 0.91) and Pro (0.89 vs 0.95) in PPI. Compared to HiPSF, PPI had better digestible AA profile for growing pigs. However, no differences were detected for the digestibility of most AA when diets were supplemented with MC.