Page 91 - Small Animal Clinical Nutrition 5th Edition

Macronutrients 91

mals fed the test protein ÷ slope of response curve for animals Table 5-15. Total tract crude protein (CP) digestibility of cat foods
containing plant and animal protein sources.*
VetBooks.ir fed the reference protein. The slope ratio method usually uses Carbohydrate Total tract CP
growth as the response and may be sensitive to different levels
of energy (Brown, 1989).
1
Corn
Fish meal
Ileal-cannulated dogs can also be used to determine protein Protein source source digestibility (%)
78
Meat meal 2,4 Corn 91
quality (Walker et al, 1994). Protein digestibility coefficients
Soy protein - -
based on collection and analyses of digesta from the terminal With 25% butter 3 Cornstarch 91
ileum give a more accurate measure of protein nitrogen With 25% lard 3 Cornstarch 92
With 25% unbleached
absorbed than those based on fecal collections. Values deter-
tallow 3 Cornstarch 90
mined from terminal ileal digesta exclude endogenous protein With 25% bleached tallow 3 Cornstarch 90
secretion from the GI tract and contributions from intestinal With 25% chicken fat 3 Cornstarch 90
With 25% yellow grease 3 Cornstarch 90
microflora. Ileal collection eliminates the large intestine and
Corn gluten meal 1,2,4 Corn 74
bacterial fermentation as sources of error. Use of ileal-cannulat- Corn 70
ed dogs has enabled researchers to study the effects of feeding Corn 86
Chicken and chicken
various protein sources and carbohydrates on digestibility and
by-product 5 Cornstarch 87
protein quality. Tables 5-13 and 5-14 summarize recent work With 12.49% beet pulp 5 Cornstarch 83
with ileal-cannulated dogs and demonstrate the differences in With 8.07% Solka Floc 5 Cornstarch 88
With 3.91% citrus pectin,
quality among various protein sources. Because of the compli-
3.34% locust bean gum,
cations involved with using ileal-cannulated cats (Mawby et al, 2.22% carob bean gum,
1999), no published studies have investigated protein quality 1.66 guar gum 5 Cornstarch 59
With 6.26% Solka Floc,
using this model. As a result, only total tract crude protein
2.08% gum arabic 5 Cornstarch 86
digestibility data are available for cats (Table 5-15). With. 9.04% beet pulp,
Finally, stable isotopes have been used to study protein 3.26% rice bran,
1.51% citrus pectin,
quality. Whole body nitrogen flux can be determined using
1.22% carob bean gum 5 Cornstarch 83
15 13
N-glycine and C-leucine. These markers have been used Chicken meal 4 Corn 86
extensively in human pediatrics (Bolster et al, 2001; Zello et Poultry meal 6 Not available 94
With 10% peanut hulls 6 Not available 84
al, 2003), human geriatrics (Chevalier et al, 2003; Gibson et
With 10% beet pulp 6 Not available 93
al, 2002) and in young-adult/aging dogs (Williams et al, With 10% alfalfa meal 6 Not available 92
1
2001). *Adapted from Funaba M, Tanaka T, Kaneko M, et al. Fish meal
versus maize gluten meal as a protein source for dry cat food.
Protein quality varies with the animal species; poor quality
Journal of Veterinary Medical Science 2001; 63: 1355-1357.
proteins for one monogastric species may not be poor quality in 2 Funaba M, Matsumoto C, Matsuki K, et al. Comparison of maize
other monogastrics (e.g., dogs vs. cats). The sensitivity of qual- gluten meal and meat meal as a protein source in dry foods for-
mulated for cats. American Journal of Veterinary Research 2002;
ity depends on the rate of growth or the level of demand to syn- 3
63; 1247-1251. Kane E, Morris JG, Rogers QR. Acceptability and
thesize proteins for needs such as lactation, trauma, athletic digestibility by adult cats of diets made with various sources and
performance and stress. Animals that are relatively inactive, levels of fat. Journal of Animal Science 1981; 53: 1516-1523.
4 Funaba M, Oka Y, Kobayashi S, et al. Evaluation of meat meal,
mature and under no stress may not be very sensitive to mod-
chicken meal and corn gluten meal as dietary protein sources of
erate differences in protein quality (Brown, 1989). protein in dry cat food. Canadian Journal of Veterinary Research
5
2005; 69: 299-304. Sunvold GD, Fahey JC Jr, Merchen NR, et al.
Protein/Amino Acid Requirements Dietary fiber for cats: In vitro fermentation of selected fiber
sources by cat fecal inoculum and in vivo utilization of diets con-
Factors Affecting Requirements taining selected fiber sources and their blends. Journal of Animal
6
New proteins can be synthesized from dietary amino acids or Science 1995; 73: 2329-2339. Fekete SG, Hullar I, Andrasofszky
E, et al. Effect of different fibre types on the digestibility of nutri-
nonessential amino acids that were previously synthesized by
ents in cats. Journal of Animal Physiology and Animal Nutrition
the body. By definition, essential amino acids used in protein 2004; 88: 138-142.
synthesis must be provided by food.Therefore, animals do not
have a requirement for protein per se but have an amino acid
requirement. The amount of each amino acid that an animal an amount of amino nitrogen that can be used for synthesis of
requires varies based on factors such as growth, pregnancy, nonessential amino acids.
lactation and some disease states. In addition to requiring spe- The amount of protein or amino acids that must be includ-
cific essential amino acids, dogs and cats have a requirement ed in a pet food also depends on how much food the animal
for building blocks (carbon skeletons and nitrogen) for consumes. It is easy to understand why animals that are grow-
nonessential amino acids. The building blocks for nonessen- ing, pregnant or lactating require dietary protein to support
tial amino acids can either be derived from excess essential new tissue growth and milk production. If an animal only con-
amino acids that are broken down and reassembled into sumes small quantities of food to meet its energy requirement
nonessential amino acids or from other nonessential amino then the food needs to have a greater protein concentration to
acids in food. Thus, a complete statement of amino acid meet the animal’s protein requirement. For example, high-calo-
requirements should include all the essential amino acids and rie pet foods should have more protein as a percentage of the