Diet and Nutrition

• Complete diets• Cost• Allergies• Quality ingredients• Weight management• Special needs

Nutrients

• Plants are composed primarily of fibrous carbohydrates, and store most of their reserve food as starch

• Animals consist mostly of proteins and lipids, and store most of their reserve food as as fat

Water• Animals have three sources

of water: – Water which they drink– Water ingested as a

component of food and other drinks

– Metabolic water, which is derived from the digestive breakdown of carbohydrates, fats, and proteins.

• Metabolic water is the primary source of water for animals during hibernation

Water• Water has many functions:

– Transports nutrients throughout the body

– Used in most biochemical reactions

– Helps regulate body temperature

– Elimination of body wastes– Constituent of the synovial

fluid that lubricates joints

• Animals will die more rapidly from lack of water than from lack of any other dietary substance

Carbohydrates• Carbohydrates are the major

energy storage and structural constituent of plants

• They include: – Monosaccharides– Disaccharides– Oligosaccharides– Polysaccharides

• Plant polysaccharides, starch and fiber are the principal carbohydrate constituents in manufactured petfoods

Carbohydrates

• Major source of energy utilized for many body functions

• Essential for the metabolism of other nutrients

Carbohydrates• Monosaccharides – Simple sugars that can be absorbed directly from the

gastrointestinal tract include:• Glucose

– Principal carbohydrate used for energy– End-product of starch

• Fructose– Found in honey, fruits, and some vegetables

• Galactose– Derived from the digestion of lactose

Carbohydrates

• Disaccharides– Two monosaccharide

units linked together • Sucrose (table sugar)

– Composed of one molecule of glucose linked with one of fructose

• Lactose (milk sugar) – Composed of a

molecule of glucose linked to a molecule of galactose

Carbohydrates

• Disaccharides– Digestion requires the

enzymes sucrase and lactase• Young animals have high

levels of lactase and low levels of sucrase and thus should not be fed formulas containing table sugar during the first few weeks of life

Carbohydrates• Galactooligosaccharides – Short chains of galactose and are found in soybeans– Partially digested portion promotes the growth of

beneficial colonic bacteria

• Polysaccharides– Long complex chains of monosaccharide units linked

• Primary types: – Starch

» composed of soluble “alpha” monosaccharide – Fiber

» composed of insoluble “beta” monosaccharide units

Fats

• Dietary fat – Concentrated source of

energy, essential fatty acids and Fat-soluble vitamins

– Enhances palatability and gives desirable texture

Fats

• Lipids – Oils

• High percentage of short-chain or unsaturated fatty acids are liquid at room temperature

– Fats• High percentage of

saturated fatty acids and longer-chained fatty acids are solids at room temperature

Fats

• Fatty acids– Classified by size and

number of double bonds• Saturated

– No double bonds

• Monounsaturated– One double

• Polyunsaturated – More than one double

bond

Fats• Most commercial dry dog foods

for adult maintenance contain 5% to 10% fat

• Poultry is the most common source of fat used in dog and cat foods, although beef and pork lard are also used

• Corn, soybean, and safflower oils are the most commonly used vegetable fats in petfoods

• Fish oils and flaxseed are rich in omega-3 fatty acids

Fats• Dogs are more efficient

than cats in digesting fats • Excess dietary fat may

promote obesity

• Overweight cats are more likely to develop diabetes mellitus, experience lameness, have skin disorders, and have a shorter life expectancy

Protein• Protein constitutes nearly

50% of the dry matter of an animal’s body

• Composed of amino acids attached to each other by peptide bonds

• amino acids are important as structural components of body tissues

Protein

• 10 a.a. cannot be synthesized and are dietary essentials

• (PVT TIM HALL)– Phenylalanine– Valine– Threonine– Methionine– Arginine

– Tryptophan– Histidine– Isoleucine– Leucine– Lysine

Protein

• Taurine (not a true a.a)– Roles in feline reproduction, bile acid conjugation,

retinal function (vision), and normal function of the myocardium

– Cats cannot synthesize taurine and require a continual dietary source

– Present only in animal tissues – Signs of taurine deficiency: • central retinal degeneration (resulting in blindness) • dilated cardiomyopathy (heart failure)

Protein

• Structural and functional roles proteins play in dogs and cats include:– Growth– Tissue and cellular repair– Enzymes– Hormones– Antibodies– Carrier proteins– Sources of energy

Protein

• Symptoms of advanced protein deficiency include: – Decreased food intake– Growth inhibition and/or

weight loss – Lowered levels of blood

proteins – Muscular wasting– Emaciation– Death

Protein

• Physiologic states requiring protein intake above that needed for maintenance– Growth– Pregnancy– Lactation– Geriatric Age

Protein

• Protein is the most expensive major component of companion animal diets. – Raw materials of animal origin not suitable for human

consumption constitutes used in formulating petfoods – Animal meats are by-products

• Meat-packing • Poultry-processing• Fish-canning industries

– Important sources of high-quality protein, energy, and minerals.

Protein

• Plant proteins have been a reliable source of nutrients in petfoods for decades. – Soybean meal is the most common plant protein

used in dog diets. – Most other cereal proteins are low in the amino

acids lysine, methionine, leucine, and tryptophan. • Animal proteins are preferred in companion

animal diets, especially those of cats