The nutritive value of selected commercial dry dog foods

Abstract

The goal of this study was to analysed and compared the nutrients content of dry dog foods with nutrient content, which is declared
by the manufacturer of the dry dog foods. Fifteen dry dog foods bought in the Slovakia were analysed for dry matter, crude protein,
crude fat, crude fiber, nitrogen free extract and ash concentration. Nutrients analysis of dry dog foods were realised in Laboratory
of Quality and Nutritional Value of Feeds according to the regulation of the Slovak Ministry of Agriculture no. 2145/2004-100. We
found, that only 6 from 15 dry dog food samples were in interval ±5% from declared crude protein concentration; no sample was
in interval ±5 % from declared crude fat concentration; only 2 from 15 dry dog food samples were in interval ± 5 % from declared
crude fiber concentration; only 4 from 15 dry dog food samples were in interval ±5 % from declared ash concentration. Analysed
dry dog food samples have very different nutritive value in comparison to on bale declared nutritive value. The highest shortage
was detected by the fat concentration. The highest excess was detected by the fiber concentration.

Full text

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Acta fytotechn zootechn, 19, 2016(1): 25-28
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© Slovak University of Agriculture in Nitra
Faculty of Agrobiology and Food Resources
1 Introduction
The most important consideration in choosing
a commercial pet food for a companion animal is its
nutrient content. Nutrient content refers not only to
the exact levels of nutrients in the food, but also to the
digestibility and availability of all the essential nutrients
(Case et al., 2011). There are many types of pet foods:
dry pet foods, wet pet foods, semi moist pet foods
(Tvarožková, 2015). Dry dog foods are very convenient
for owners and are the most common type of pet food
bought by pet owners (Harlow, 1997). In general, these
products are more economical to feed than wet or
semi moist foods and their store well because of their
low moisture content (Samuelson and Cutter, 1991).
There are two primary types of wet pet foods: those
that provide complete and balanced nutrition and
those that provide a dietary supplement or treat in the
form of a canned/pouched meat or meat by-product.
Complete and balanced wet foods may contain blends of
ingredients such as muscle meat, poultry or sh meats or
by-products, cereal grains, texturized vegetable protein
and vitamins and minerals. Semi moist pet foods contain
15% to 30% water and include fresh or frozen animal
tissues, cereal grains, fats and simple sugar as their
principal ingredients. These products are softer in texture
than dry pet foods, which contribute to their acceptability
and palatability for some animals (Case et al., 2011). In
general, wet foods are more palatable and digestible
than many dry pet foods and they contain ahigher dry
matter proportion of protein and fat (Kallfelz, 1989). The
aim of this study was to compare the analysed nutrients
content of dry dog food with nutrients content, which is
declared by the manufacturer of the dry dog food. We
focused on selected commercial dog foods bought in
Slovakia.
2 Material and methods
Fifteen dry dog food samples bought in Slovakia were
used for nutrients analysis. Dry dog food samples were
bought in dierent pet shops and were from dierent
producers. Analysed dry dog foods were determined for
dierent types of dogs. Nine from fteen analysed dry
dog foods were used for feeding of adult dogs in normal
condition; two dry dog food samples were used for
feeding of working dogs and four dry dog food samples
were used for feeding of puppies. Five dry dog foods were
made in Slovakia, 10 dry dog foods were made in other
countries. Manufacturer‘s declared nutrients content of
analysed dry dog foods are shown in table 1.
Analysis of dog food samples were realised at Department
of Animal Nutrition (Slovak University of Agriculture in
Nitra) in Laboratory of Quality and Nutritional Value of
The nutritive value of selected commercial dry dog foods
Michal Rolinec*, Daniel Bíro, Branislav Gálik, Milan Šimko, Miroslav Juráček,
KristínaTvarožková, Andrea Ištoková
Slovak University of Agriculture in Nitra, Slovak Republic
Article Details: Received: 2015-11-03 | Accepted: 2015-11-06 | Available online: 2016-03-24
dx.doi.org/10.15414/afz.2016.19.01.25-28
The goal of this study was to analysed and compared the nutrients content of dry dog foods with nutrient content, which is declared
by the manufacturer of the dry dog foods. Fifteen dry dog foods bought in the Slovakia were analysed for dry matter, crude protein,
crude fat, crude ber, nitrogen free extract and ash concentration. Nutrients analysis of dry dog foods were realised in Laboratory
of Quality and Nutritional Value of Feeds according to the regulation of the Slovak Ministry of Agriculture no. 2145/2004-100. We
found, that only 6 from 15 dry dog food samples were in interval ±5% from declared crude protein concentration; no sample was
in interval ±5% from declared crude fat concentration; only 2 from 15 dry dog food samples were in interval ±5% from declared
crude ber concentration; only 4 from 15 dry dog food samples were in interval ±5% from declared ash concentration. Analysed
dry dog food samples have very dierent nutritive value in comparison to on bale declared nutritive value. The highest shortage
was detected by the fat concentration. The highest excess was detected by the ber concentration.
Keywords: dogs, dry food, nutrients concentration, evaluationn
*Corresponding Author: Michal Rolinec, Department of Animal Nutrition, Faculty of Agrobiology and Food Resources,
Slovak University of Agriculture in Nitra, Trieda Andreja Hlinku 2, 94976 Nitra, Slovak Republic.
E-mail:michal.rolinec@uniag.sk
Short Communication

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© Slovak University of Agriculture in Nitra
Faculty of Agrobiology and Food Resources
Acta fytotechn zootechn, 19, 2016(1): 25–28
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Feeds. During time from purchase to analyse of dry dog
food samples were these samples stored at -40 °C in
adeep-freeze cabinet (EVERmed, Italy). Analysis of crude
protein, crude fat, crude ber and ash concentration was
realized according to the regulation of the Slovak Ministry
of Agriculture no.2145/2004-100. Content of dry matter
(DM) was determined gravimetric by drying of sample to
constant weight by temperature 103±2°C. Crude protein
was measured using the micro-Kjeldahl method, crude
fat: extraction by light petroleum, ash: ashing to the use
of amue furnace by 550°C, crude ber: gravimetrically
as the residue remaining after extraction in acid and alkali
reagent. Nitrogen free extract (NFE) and organic matter
(OM) was calculate (NFE = dry matter-crude protein-
crude ber-fat-ash, OM=dry matter-ash). Concentration
of analysed nutrients is shown in grams per kilogram of
original matter. Nutrient concentration in dry dog food
declared by manufacturer was crib from bale of dry dog
food. Results were statistical analyzed in statistic program
SAS Enterprise Guide 5.1. (SAS Institute, Inc).
3 Results and discussion
Like all living animals, dogs require a balanced diet
to grow normally and maintain health once they are
mature. A dry dog food is the most common type of
dog food. Many dog owners prefer feeding dry foods
because they can leave a bowl of food available to their
dog for a period of time without worrying about spoilage
(Samuelson and Cutter, 1991). In our study we focused on
nutrients concentration determination of dry dog food
bought in Slovakia. Nutritive value of analysed dry dog
food samples is shown in table 2.
The nutrient content recommendations for a dry dog
food published by Case et al. (2011) are: no less than
26 % of crude protein; no less than 15 % of crude
fat; not more than 5 % of crude ber; carbohydrate
concentration about 37%; mineral content is estimated
to be about 7 % and no more than 10 % of moisture.
From our results is clear, that average concentration of
dry matter, crude protein, crude ber and ash is similar
with recommendation. However, some of these dry dog
food samples have low concentration of crude protein
and ash. Crude fat was anutrient with shortage in almost
all dry dog food samples.
The aim of this study was to compare analysed content
of nutrients with content of nutrients, which is declared
by manufacturer. The average dierence between
analysed and declared nutrients content of some dry dog
foods bought in Slovakia is shown in table 3. Dierence
between analysed and declared nutrient content was in
dry dog foods very high. This statement conrms value
of standard deviation as well coecient of variation.
Similar results of dierences in nutrient concentration in
pet food published Lasek et al. (2013). Analysed dry dog
foods have very dierent nutritive value in comparison
to declared nutritive value. Without correct information
about nutrient content in dog food is correct feeding of
dogs impossible. Then the result of feeding with such
feed is, that some dogs are overfeed or underfeed with
concrete nutrient and this can lead to various diseases.
Only 6 from 15 samples had crude protein content in
range of±5% in comparison to declared crude protein
content. In one sample was the crude protein content less
Table 1 Manufacturer‘s declared average nutrients content of dry dog foods (gkg-1 original matter)
Nutrient n xsd xmin xmax CV
Crude protein 15 265.67 33.75 200.00 300.00 12.70
Crude fat 15 155.00 40.84 75.00 220.00 26.35
Crude ber 15 26.53 7.74 15.00 42.00 29.19
Ash 15 70.07 12.63 51.00 90.00 18.02
Table 2 Average nutrient content in analysed dry dog food samples (gkg-1 original matter)
Nutrient n xs.d. xmin xmax CV
Dry matter 15 929.23 14.40 900.90 956.20 1.55
Crude protein 15 279.10 40.47 191.70 346.6 14.50
Crude fat 15 123.24 34.44 47.70 184.70 27.95
Crude ber 15 31.79 12.19 18.40 61.50 38.34
Nitrogen free extract 15 417.67 50.73 328.00 549.50 12.15
Ash 15 77.43 9.83 58.90 92.00 12.70
Organic matter 15 851.79 17.62 819.60 883.10 2.07

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© Slovak University of Agriculture in Nitra
Faculty of Agrobiology and Food Resources
than 90% from declared value. It is known, that dietary
protein serves several important functions. Dog owners
must watch especially this nutrient to cover daily needs
of essential amino acids of dog as published Kronfeld
(1982). The worst situation was by the fat concentration.
In 12 of 15 samples were concentration of fat under 90%
from declared fat content. We detected decit of fat in
high of minus 30% or more in 4 from 15 dry dog food
samples. This decit of fat concentration in dry dog food
is dangerous, because the fat is the main source of energy
(Mudřík et al., 2014) and fatty acids (Herkeľ et al., 2014;
Varga, 2014) and belongs to most digestible nutrient
(Píšová, 2015). Fat in the diets for companion animals
also plays a role in contributing to the palatability and
texture of food (Bauer, 2006). This high decit of fat in
dry dog food could lead to the energy shortage mainly
by dogs used for dierent kinds of work. Dietary ber
cannot by broken down by enzymes of intestinal tract
of dogs to monosaccharide units for absorption in the
small intestine. However a part of ber can be digest
by microbes found in the large intestine of dogs. This
bacterial fermentation produces short-chain fatty acids
and other end products. The short-chain fatty acids are
an important energy source for epithelial cells lining
the gastrointestinal tract and these ber sources help
to maintain gastrointestinal tract health (Alvarez and
Sanchez, 2006; Case et al., 2011). Only two samples were
in range of±5% from declared crude ber content. Nine
from 15 samples contain 120% or more ber and 3 from 15
samples contain more than 160% of ber in comparison
to declared ber content. So high concentration of ber
can limits digestibility of other nutrients. Minerals are
inorganic elements that make up only 4 % of animals
total body weight, nonetheless, the essential minerals
must be present in the diet to sustain life and maintain
health (Case et al., 2011). Minerals are essential mainly for
growth of young animals (Hanušovský, 2014). However
long-time intake of food with high concentration of
minerals has bad eect on health (Tvrdá et al., 2013). We
found that only 4 from 15 samples have content of ash
in range±5% from declared value. Two from 15 samples
contain 150 or more percent of ash in comparison to
declared ash content. Long-time feeding with such food
may be unhealthy for dogs.
4 Conclusions
Our results point out on the most common limitations
of nutrient concentration declarations of dry dog
foods bought in Slovakia. Only 6 from 15 samples
had laboratory analysed crude protein concentration
in the range of ±5 % from declared crude protein
concentration. We detected decit of fat in level of minus
30% or more in 4 from 15 dry dog food samples. This
high deciency in fat concentration could lead to the
energy shortage mainly by dogs used for dierent kinds
of work. 9 from 15 samples contain plus 20% or more
ber and 3 from 15 samples contain more than plus
60 % of ber in comparison to declared ber content.
High concentration of ber restrict digestibility of other
nutrients. 2 from 15 samples contain over 50% of ash in
comparison to declared ash content. Long-time feeding
with such food may be unhealthy for dogs. Feeding
without exact knowledge about nutrient concentration
in dog foods can never cover the nutrient needs of dog.
Therefore it is necessarily exact declaration of nutrient
concentration of dog foods by manufacturer.
Acknowledgments
This work has been supported by the Excellence Center
for Agrobiodiversity Conservation and Benet project
implemented under the Operational Programme
Research and Development nanced by European Fund
for Regional Development, ITMS26220120015.
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