Chapter 41 Chapter 41 Animal NutritionAnimal Nutrition

Nutritionally Adequate DietNutritionally Adequate Diet

FuelFuel Biosynthesis raw materialsBiosynthesis raw materials Essential nutrientsEssential nutrients

Fueling LifeFueling Life

Balance caloric intake and outputBalance caloric intake and output Excess stored as glycogen and fatExcess stored as glycogen and fat Fat kcal: 9 per gramFat kcal: 9 per gram

Glucose and fat preferred fuel (amino Glucose and fat preferred fuel (amino acids not stored)acids not stored)

Glucose-major fuelGlucose-major fuel Metabolism under hormonal controlMetabolism under hormonal control

Homeostatic Mechanisms(1) When glucose levels rise above a set

point, (2) pancreas secretes insulin into the blood.(3) Insulin enhances the transport of

glucose into body cells and stimulates the liver and muscle cells to store glucose as glycogen, dropping blood glucose levels.

(4) When glucose levels drop below a set point, (5) the pancreas secretes glucagon into the blood.

(6) Glucagon promotes the breakdown of glycogen and the release of glucose into the blood, increasing the blood glucose levels.

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See page 851—help identify processSee page 851—help identify process

Caloric ImbalancesCaloric Imbalances UndernourishmentUndernourishment:: chronic chronic

caloric deficiencycaloric deficiency

OvernourishmentOvernourishment (obesity):(obesity): excessive food intakeexcessive food intake Leptin-appetite Leptin-appetite

supressing hormonesupressing hormone

MalnourishmentMalnourishment:: essential essential nutrient deficiencynutrient deficiency

Leptin deficient rat on leftLeptin deficient rat on left

Supplying carbon skeletonsSupplying carbon skeletons

Build proteins, carbohydrates, lipidsBuild proteins, carbohydrates, lipids

Essential NutrientsEssential Nutrients

Materials that must be obtained in Materials that must be obtained in preassembledpreassembled form. (Why???) form. (Why???)

MalnourishmentMalnourishment:: essential nutrient essential nutrient deficiencydeficiency

Essential amino acidsEssential amino acids:: 88

Protein deficiency-most Protein deficiency-most common type of common type of malnutritionmalnutrition

•Complete & incomplete proteinsComplete & incomplete proteins•Complementary proteinsComplementary proteins•Limiting amino acids.Limiting amino acids.

Special AdaptationsSpecial Adaptations

Adelei penguins-Adelei penguins-AntarticaAntartica

Use muscle protein Use muscle protein to build new to build new feathersfeathers

Essential fatty acidsEssential fatty acids:: unsaturated fatty acidsunsaturated fatty acids linoleic and alpha-linolenic (linoleic and alpha-linolenic (ΩΩ-3; -3; ΩΩ-6)-6)

phospholipids in cell membranes—phospholipids in cell membranes—esp. nervous tissueesp. nervous tissue

Omega-3 fatty acids have been found to be Omega-3 fatty acids have been found to be beneficial for the heart. Positive effects include beneficial for the heart. Positive effects include anti-inflammatory and anti-blood clotting actionsanti-inflammatory and anti-blood clotting actions, , lowering cholesterol and triglyceride levels, and lowering cholesterol and triglyceride levels, and reducing blood pressure reducing blood pressure

VitaminsVitamins: : many are organic coenzymes (B-vits)many are organic coenzymes (B-vits)

a) water soluble-excreteda) water soluble-excreted

b) fat soluble-stored in adipose b) fat soluble-stored in adipose tissue—can be toxic in excesstissue—can be toxic in excess A,D,E,KA,D,E,K A) Vision-Retinol; skin A) Vision-Retinol; skin D) bone development—rickets—bowed D) bone development—rickets—bowed

legslegs E) antioxidantE) antioxidant K) blood clottingK) blood clotting

Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings

Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings

Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings

MineralsMinerals: inorganic cofactors: inorganic cofactors

Calcium: bones, muscle contraction, Calcium: bones, muscle contraction, nerve impulsesnerve impulses

Iodine: goiter: naturally occurring in Iodine: goiter: naturally occurring in marine watermarine water

Iron: oxygen transport (hemoglobin)Iron: oxygen transport (hemoglobin)

Food types/feeding mechanismsFood types/feeding mechanisms OpportunisticOpportunistic HerbivoreHerbivore: eat autotrophs: eat autotrophs CarnivoreCarnivore: eat other animals: eat other animals OmnivoreOmnivore: both: both Feeding AdaptationsFeeding Adaptations Suspension-feedersSuspension-feeders: sift food : sift food

from water (baleen whale)from water (baleen whale) Substrate-feedersSubstrate-feeders: live in or on : live in or on

their food (leaf miner) their food (leaf miner) (earthworm: (earthworm: deposit-feederdeposit-feeder))

Fluid-feedersFluid-feeders: suck fluids from : suck fluids from a host (mosquito); a host (mosquito); hummingbirdshummingbirds

Bulk-feedersBulk-feeders: eat large pieces : eat large pieces of food (most animals)of food (most animals)

Overview of food processing-4 stagesOverview of food processing-4 stages 1-1-IngestionIngestion:: act of act of

eatingeating 2-2-DigestionDigestion: process of : process of

food break downfood break down

enzymatic hydrolysisenzymatic hydrolysis

3- 3- AbsorptionAbsorption: cells : cells take up small moleculestake up small molecules

4- 4- EliminationElimination: removal : removal of undigested materialof undigested material

A)A) intracellularintracellular: breakdown within cells : breakdown within cells (sponges); or within membrane (sponges); or within membrane (paramecium)(paramecium)

B) extracellularB) extracellular: breakdown outside : breakdown outside cells (most animals)cells (most animals)

alimentary canals (digestive tract) alimentary canals (digestive tract)

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Fig. 41.11

Extracellular Extracellular digestiondigestion

HydraHydra 2 tissue layers2 tissue layers Inner layerInner layerForms digestiveForms digestiveCavityCavity

Incomplete digestiveIncomplete digestiveSystemSystem (only 1 opening)(only 1 opening)

Mammalian digestionMammalian digestion (complete- 2 openings)(complete- 2 openings)

PeristalsisPeristalsis:: rhythmic waves of contraction by rhythmic waves of contraction by smooth musclesmooth muscle

Sphincters:Sphincters: ring-like valves that regulate ring-like valves that regulate passage of materialpassage of material

Accessory glands:Accessory glands: salivary glands; pancreas; salivary glands; pancreas; liver; gall bladderliver; gall bladder

Mammalian digestion: Mammalian digestion: Ingestion & initial digestion Ingestion & initial digestion

Oral cavityOral cavity Mechanical and chemical Mechanical and chemical

digestiondigestion Teeth-reduce size\increase Teeth-reduce size\increase

surface areasurface area ••salivary amylase salivary amylase ••bolusbolus

Pharynx-juncturePharynx-juncture

• •epiglottis-cartilage flap, closes epiglottis-cartilage flap, closes

off trachea when swallowingoff trachea when swallowing

Esophagus—food tubeEsophagus—food tube

Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings

Fig. 41.14

StomachStomach BolusBolus passes through passes through Cardiac Cardiac Sphincter-Sphincter-enters stomachstomach

(occasional backflow—heartburn)(occasional backflow—heartburn) Preliminary digestion, stores food Preliminary digestion, stores food Mechanical (churning) and Mechanical (churning) and

chemical digestionchemical digestion

gastric juice secreted:gastric juice secreted: Contains HCl & pepsinContains HCl & pepsin

(pepsinogen activated to (pepsinogen activated to pepsin by pepsin by

HCl)-- begins protein digestion HCl)-- begins protein digestion

Positive feedback-Positive feedback-increasingly more pepsin increasingly more pepsin activation activation

Small Intestine: Digestion & Small Intestine: Digestion & Absorption: Absorption: Digestion of carbohydrates, Digestion of carbohydrates,

proteins, nucleic acids, fatsproteins, nucleic acids, fats Acid ChymeAcid Chyme passes through passes through Pyloric SphincterPyloric Sphincter into Small into Small

intestine (duodenum)intestine (duodenum) bilebile: secreted into S.I.: secreted into S.I.

Produced by liverProduced by liver Stored in Gall BladderStored in Gall Bladder Bile salts-emulsifiers ( no enzymes)—break up & coat fatBile salts-emulsifiers ( no enzymes)—break up & coat fat

Some proteases secreted by intestineSome proteases secreted by intestine Pancreas: secretes bicarbonate & enzymesPancreas: secretes bicarbonate & enzymes

Amylases (carbs); lipases (fats); nucleasesAmylases (carbs); lipases (fats); nucleases some proteases secreted in inactive form and activated by some proteases secreted in inactive form and activated by

a membrane-bound enteropeptidasea membrane-bound enteropeptidase

Activation of pancreatic peptidases Activation of pancreatic peptidases within the intestinewithin the intestine

3. Nutrient Absorption3. Nutrient Absorption S.I. highly foldedS.I. highly folded

Villi (finger-like projections) & microvilli Villi (finger-like projections) & microvilli (appendages of villi) increase absorptive (appendages of villi) increase absorptive surface surface

Small vessels in villi absorb:Small vessels in villi absorb: Lipids into the lacteals –to veinsLipids into the lacteals –to veins Other nutrients into Hepatic Portal Other nutrients into Hepatic Portal

Vessel to LiverVessel to Liver

In Lumen-Chylomicrons form: In Lumen-Chylomicrons form: (complex of fat, cholesterol, & (complex of fat, cholesterol, & protein)protein)

Carried by lacteals; dump Carried by lacteals; dump into veins returning to the into veins returning to the heartheart

Other nutrients—travel to liver Other nutrients—travel to liver via Hepatic portal vessel via Hepatic portal vessel

Large intestine Large intestine (colon)-absorb water; (colon)-absorb water; concentrate residueconcentrate residue

Bacterial symbionts-Bacterial symbionts-generate some generate some vitamins—K, biotinvitamins—K, biotin

Cecum-small pouchCecum-small pouch At tip is the AppendixAt tip is the Appendix

FecesFeces Rectum--storageRectum--storage Anus--eliminationAnus--elimination

Large IntestineLarge Intestine

Hormonal Regulation of DigestionHormonal Regulation of Digestion

Gastrin food---> stomach wall ---> gastric Gastrin food---> stomach wall ---> gastric juicejuice

Enterogastrones (duodenum)Enterogastrones (duodenum) 11. Secretin. Secretin - - acidic chyme---> secretin --> pancreas to acidic chyme---> secretin --> pancreas to

release bicarbonate (neutralize chyme)release bicarbonate (neutralize chyme)

2. 2. CholecystokininCholecystokinin (CCK) (CCK) amino/fatty acids---> pancreas to release amino/fatty acids---> pancreas to release

enzymes and gall bladder to release bileenzymes and gall bladder to release bile

Evolutionary adaptationsEvolutionary adaptations Dentition: an animal’s assortment of Dentition: an animal’s assortment of

teethteeth Digestive system lengthDigestive system length

Herbivores-longerHerbivores-longer SymbiosisSymbiosis RuminantsRuminants

Symbionts: koala-- enlarged cecum, symbiotic bacteria ferment finely shredded eucalyptus leaves.

Ruminants—4 stomach chambersRuminants—4 stomach chambers—microbial action—microbial action

Well developed for vegetation: which include deer, cattle, and sheep.