III. Protein

A. 2 Major Considerations

1. Completeness - are all 10 essential amino acids present?

a. This is true for : milk, meat, eggs, soybeans

b. Incomplete ones: gelatin, flour, wheat

2. Biological Value - % of protein retained by the body

Egg	100%	meat scraps	50%
Fishmeal & milk	92%	whole wheat	48%
Liver	79%	whole corn	45%
Beef	78%	gelatin	0% (no trypt)
SBM	67%

B. most dog and cat food contains animal and plant protein, and grains to yield a BV of ~70%

1. As pets get older, feeding excessive amounts of protein can affect kidneys

C. Processing affects protein quality - becomes bound thus indigestible

D. Protein is usually:

1. 80% digestible for dry food

2. 84% for soft-moist food

3. 90% in canned meat diets

E. Requirements (dogs)

1. 8 - week old pups

a. 18% digestible protein

2. 16 - week old pups

a. 17.2% digestible protein

3. 9 mo. - 15 mo.

a. ~16% digestible protein

4. > 4 years

a. Should decrease protein intake (?? discuss negative effects of High-Pro dog food)

F. Requirements (cats)

1. growing kittens

a. 35% high BV protein

2. Adult cats

a. At least 20% digestible protein

3. Cats have a much greater protein requirements than dogs because:

a. Greater activity of their amino acid catabolic enzymes in the liver.

b. Cats are sensitive to arginine deficiency

i One meal devoid of arginine results in hyperammonemmia in less than an hour

c. Cats have a greater requirement for S amino acids

i Thick hair coat requires these amino acids

ii Specific requirement for the amino sulfonic acid taurine

4. Taurine

a. Uniquely important in cat nutrition

b. Dogs - synthesize from cystine and methionine

c. Synthesis limited in cats (deficiency = visual impairment)

d. High fiber diets increase the need because of bile losses

e. Found in animal tissues NOT plants

IV. Fat

A. Important for palatability

1. especially with pet foods, people like to see their pets enjoy the meal they are consuming.

B. Supplies essential fatty acids

1. Essential Fatty Acids (Linoleic) Except cats require Arachidonic - can not synthesize

2. Dogs and cats can synthesize linolenic acid from linoleic acid, so they only require linoleic (except cats)

C. Sources are lard, suet, corn oil, cottonseed oil, olive oil, soybean oil, & safflower oil

D. usually not a problem in commercial pet foods. Fat is added to the feed, and then sprayed on after extrusion (for palatability)

E. excess = obesity and(or) fatty stools

V. Carbohydrates

A. Not very much is known.

1. Dogs can utilize 65 to 70% of dietary CHO

2. Cats can utilize 35 to 40% dietary CHO

B. Because they are poorly digested, they are usually cooked (potatoes, oats, corn)

1. High dietary “raw” starch can cause diarrhea

2. Milk can also cause diarrhea (lactose intolerant)

C. Inexpensive

VI. Fiber

A. Fiber absorbs water, and produces more volume of stool than

B. Stimulates and maintains intestinal action (motility)

1. especially in senile and inactive dogs

C. Most pet foods have between 1 and 8% fiber

D. “Reducing” diets may contain more (up to 32%) for the bulk (fill) effect of fiber

E. Sources commonly used are:

1. cellulose

2. hemicellulose

3. lignin

4. cereal grain hulls

5. bran

6. beet pulp

7. string beans