Biol 200B 1st Edition Lecture 13Current LectureChapter 44 Animal Nutrition I. MacronutrientsII. Food processingIII. Symbiosis in digestionIV. Feedinga. mouthparts b. digestive tractAnimal Nutrition•Nutrients = substances organisms require for energy and biosynthesis (biomass)Macronutrients (organic compounds)• Proteins (Amino acids)• Carbohydrates (Sugars)•Lipids (Fatty acids)Essential nutrients must be obtained in diet; cannot be synthesized•amino acids and fatty acids•vitamins•electrolytesThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.•essential elementsProtein is the principal constituent of organs and musclesLipids contain the most energy of all the nutrientsMain stages of food processing1. Ingestion2. Digestion -mechanical digestion-chemical digestion3. Absorption-nutrient molecules enter body cells4. Elimination-undigested materialIngestion and Mouthparts•suspension feeders•deposit feeders•fluid feeders •mass feeders•Close correspondence between mouth structure and function in capturing and processing food.• There are more species of teleost fish than any other vertebrate• Great diversity in teeth and diet• Adaptive radiation in form and function to fill nichesSymbiosis in digestion: Ruminants-some animals, such as sheep and cattle, have four stomachs instead of one-Rumen: pouch where symbiotic microbes reside-use cellulase enzyme to digest cellulose and fermentation Symbionts in humans•Human intestinal tract houses 100 trillion microorganisms of up to 1000 different species•they are mutualistic: aid in polysaccharide digestion, synthesize B vitamins, protect against intestinal injury•the appendix might not be vestigialDigestive TractsDigestion: breakdown of food into smaller pieces (ultimately molecules)• mechanical digestion (e.g., chewing & churning)•chemical digestion (e.g., by enzymes)Absorption: uptake of specific nutrients by cells of the digestive tractMouth and EsophagusSalivary glands (in mouth):• amylase (starch digestion)• lipase (lipid digestion)•water + mucins = mucusBirds have a crop = expanded segment of esophagus• store ingested food prior to digestion• houses symbiotic bacteria in hoatzins, kakapos•“pigeon’s milk”StomachPepsinogen + HCl produces• Pepsin = Enzyme for protein digestionMucous prevents self-digestion.ulcer = hole in stomach epithelium caused by bacteriaSmall Intestine = Absorption (surface area)Major site of Digestion and Absorption• Intestinal cells release hormones to regulate:•Pancreas & Gall BladderGall bladder and pancreasPancreas stimulated to release:•Bicarbonate into intestine (neutralizes stomach acid)•Proteases to digest protein into amino acidsGall Bladder stimulated to release:•Bile to emulsify fat globules•Lipase to digest lipids into fatty acidsLarge IntestineFunctions:• compact waste to form feces•reabsorb water through aquaporin protein channelsAmphibians, reptiles (including birds),•and some fish have a cloaca = common terminal chamber for excretory, digestive, and reproductive