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

• Dietary fat – Concentrated source of energy, essential fatty acids and Fat-soluble vitamins – Enhances palatability and gives desirable texture

Fats

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