animal nutrition 动物营养学.ppt

Animal Nutrition Management of energy budget Diet supplies carbon skeletons and essential nutrients Ingestion, digestion, absorption, elimination Organs have specialized functions Dietary adaptations Animal Feeding Strategies Herbivores: gorillas, cattle, hares Eat mainly autotrophs (plants, algae, some bacteria) Carnivores: sharks, hawks, spiders, snakes Eat other animals Omnivores: cockroaches, crows, bears, raccoons, humans Eat plants and animals Adequate Diet Fuel For all cellular work (chemical energy) Organic raw materials For biosynthesis of new structures in the consumer Essential nutrients Substances the animal cannot make for itself Four Main Feeding Mechanisms Suspension feeders: sift small particles from the water Substrate feeders: animals the live in or on their food source; eat their way through Fluid feeders: suck nutrient-rich fluid from a living host Bulk feeders: eat relatively large pieces of food ATP Production An animal’s ATP production is mostly dependant on the food ingested Most ATP produced from the oxidation of carbohydrates, protein, and fats in the diet Protein will be oxidized last Fat results in nearly twice as much energy as proteins or carbohydrates Glucose Regulation If not growing or reproducing, excess intake stored In humans, liver and muscles store glycogen; excess stored as fat When less energy than needed is taken in, energy shuffled out of storage for use Liver first, then muscle Caloric Imbalance Undernourishment: diet chronically deficient in calories Fat utilized, muscles utilized, brain can become protein deficient Overnourishment: obesity resulting from excessive intake Body hordes fat; excess carbs tend to lead to increased carb oxidation Obesity and Human Health WHO recognizes obesity as human health problem In US, percentage of obese people has doubled in last 20 years (to 30%) Another 35% overweight Increased risk of diabetes, cardiovascular disease, cancers Inheritance major factor in obesity Obesity and Human Heal