Intro to Nutrition

the study of the body’s need and mechanisms of acquiring, digesting, transporting, and metabolizing nutrients feed costs can exceed 70% of animal production

human pig dog cat simple stomach dietary components broken down and absorbed in small intestine

cattle sheep goats moose giraffe etc. herbivorous diet in general rumen contains microbes that degrade feed -fermentation energy products absorbed here microbes then passed into abomasum final digestion and absorption in sm. intestine

microbes in hind gut break down forage fermentation products absorbed for energy

a substance in the diet that supports normal functions of the body 6 major components carbohydrates protein lipids vitamins minerals water

water (moisture) protein (crude protein) fat (crude fat) carbohydrates vitamins minerals (ash) energy NOT a nutrient

must be part of the animals diet ex: essential AA, some vitamins, some minerals species specific 50 for most monogastrics -cant be made at all or in sufficient quantities by the body deficiency = disease or decreased performance

generate energy via metabolism to generate ATP

calorie (cal) amt of heat to raise 1g water 1degC nutritionalists calorie is actually a kilocalorie (kcal)

obtained from food, beverages, metabolism (formed during chem rxn) excreted via kidney, skin, intestines functions: lubrication, cooling

important source of energy 4 kcal/g chemically CHO glucose, simple sugars, complex carbs deficiency - no specific requirement but will be manifested as an energy deficiency excess - deposited as fat in adipose tissue

6 carbon sugar the bodys major energy source primary fuel of metabolism - only source of food for brain limited body reserves in form of glycogen -chains of glucose in liver and muscle excess glucose converted to body fat large increase in glucose requirements in late pregnancy and lactation

hexoses 6 C glucose - blood sugar galactose - part of lactose fructose - part of sucrose

sucrose - table sugar -glucose and fructose lactose - milk sugar -glucose and galactose

polymers of glucose starches fiber cellulose

mostly alpha 1-4 linkages between glucoses storage form of energy plant - amylose, easily digestible animal - glycogen

major components of plant cell walls structural components of forages termed non digestible

plant cell wall gives rigidity animals lack cellulase enzyme required to break beta 1-4 linkage can be hydrolyzed in rumen

celulose –> glucose –> VFAs products are short chain volatile fatty acids acetate, propionate, butyrate these are absorbed where they are produced

fats 9 kcal/g made up of fatty acids (long medium and short chains of C) fat is stored as triglyceride (glycerol and 3 fatty acids) required for cell membranes (phospholipid bilayer) deficiency - scaly skin, tail necrosis, growth and reproductive failure excess - obesity, health problems

linoleic (18:2) and linolenic (18:3) required for membrane, prostaglandin, hormone synthesis plentiful in plant materials, fish oil, and animal fat

solid at room temp animal fats such as butter

liquid at room temperature ex veg oil

synthesized in animal form -AA from diet and synthesized in body whole proteins not absorbed broken down into AA that can then be absorbed long chains of AA