Animal Nutrition Chapter 41

The Need to Feed Animals are Herbivores Carnivores omnivores

Food and Nutrients Food Any substance, either raw or processed which is meant for human consumption Nutrients The components of food that the body can use for growth, repair and energy

Homeostatic Regulation Glucose level rises, insulin is secreted Insulintransport of glucoseliver & muscle store glucose lblood levels drop Glucagon promotes the breakdown of glycogen blood glucose levels rise Glucose level drops glucagon is made to oppose the effect of insulin

Appetite Regulating Hormones PYY is an appetite suppressant Ghrelin triggers hunger Insulin suppresses appetite Leptin suppresses appetite

Figure 41.2 A ravenous rodent Obesity related to leptin.

Types of Nutrients Carbohydrates Proteins Fats Vitamins Minerals Water

Essential Nutrients Essential AA Essential fatty acids Vitamins Minerals Undernourishment vs. malnutrition

Essential Amino Acids Animals require 20 AA Can synthesize most 8 are essential, must obtain from food How do vegetarians get all essential AA?

Essential Fatty Acids Need to obtain from food Unsaturated FA Linoleic Acid

Essential Nutrients What happens if an animal’s diet is missing an essential nutrient? Deficiency Diseases scurvy — vitamin C (collagen production) rickets — vitamin D (calcium absorption) blindness — vitamin A (retinol production) anemia — vitamin B12 (coenzyme function) kwashiorkor — protein

Vitamin Requirements of Humans: Water-Soluble Vitamins

Vitamin Requirements of Humans: Fat-Soluble Vitamins

Mineral Requirements

Intracellular Digestion in Paramecium Digestion occurs in specialized compartments Intracellular digestion occurs in protists and sponges

Gastrovascular Cavities and Extracellular Digestion Gastrovascular cavities do both digestion and distribution Ex. Cnidarians, platyhelminthes (flat worms) Two-way digestion

One Way Digestive Tracts

Stages of Food Processing Ingestion: eating or drinking Digestion : Breaking food into smaller molecules Mechanical Chemical (Enzymes) Absorption: nutrient molecules enter blood, the circulatory system transports it through out the body Elimination: undigested material passes out of the body

The Digestive System Functions like a series of tube like organs which pass through the body from the mouth to the anus Alimentary Canal Alimentary Canal can be about 30’ long Accessory organs Pancreas, Liver, Gallbladder secrete enzymes that are released into the food tube

Digestion in the Mouth

It all begins in the mouth . . . Teeth, tongue Salivary glands Mucus Amylase Only carbohydrates are digested here

Swallowing and Peristalisis Glottis and Epiglottis

From mouth to stomach: the swallowing reflex and esophageal peristalsis (Layer 2)

From mouth to stomach: the swallowing reflex and esophageal peristalsis (Layer 1)

Peristalsis Rhythmic muscular contractions propel a bolus of food

The human digestive system

Digestion in the Stomach Muscular organ Acts as a reservoir where food is prepared for digestion in the SI Produces Gastric Juices

Stomach Functions Food Storage Mechanical Digestion Chemical Digestion Secretions: Mucus EnzymePepsinogen HCL CHYME semi-fluid food mixture leaves.

Protection from Self-Digestion Protective lining Main enzyme -Pepsin is inactive Pepsinogen when secreted

Digestion in the Stomach Pepsinogen Comes in contact with HCl Pepsin Pepsin converts proteins into peptones Acidity of Gastric juices kills some bacteria that enters with food Gastric Juices  stimulated by psychological and chemical means Peristaltic process of moving chyme into the SI takes place for 6hrs

Small Intestine

Digestion in the Small Intestine Main stage of Digestion As chyme enters the SI secretes juices that are alkaline and neutralizes the acidity SI maltase,lactase,sucrase breaks disaccharides Liver secretes bile emulsifies fats Dipeptidases  dipeptides into AAs Pancreas Trypsin & Chymotrypsin break down proteins Amylase converts starch into maltose Lipase breaks fats Process is complete in about 4 hrs

Pancreas Secretes Hormones Sodium bicarbonate Digestive enzymes Lipase Trypsinogen Amylase

Liver Secretes Blood clotting enzymes Stores glycogen Bile Stored in gall bladder Emulsifies fat

Large Intestine = Colon Anatomy: Functions a. Reclaim water b. Synthesis of vitamins by E. coli Feces Rectum Anus Diarrhea Constipation

Can you name the parts and tell what they do?

Food as Fuel Carbohydrates, fats and proteins are all used to generate ATP Fats9 Calories/gm, Proteins and Carbs 4Calories/gm 1 Calorie (kilocalorie)= 1000 calories Basic Calorie need 2200 for female teens, 2500 males

Helicobacter pylori Bacteria-stomach feedback interactions Coevolution of parasite & host Free of H. pylori Colonized by H. pylori Bacteria-stomach feedback interactions H. pylori bacteria colonize stomach bacterial infection causes damaging inflammation increases stomach acidity high rate of ulcer & stomach cancer control with antibiotics inflammation of stomach inflammation of esophagus H. pylori cell damaging proteins (VacA) inflammatory proteins (CagA) Gastric ulcers, lesions in the stomach lining, are caused by the acid-tolerant bacterium Heliobacter pylori. Ulcers are often treated with antibiotics. cytokines helper T cells neutrophil cells white blood cells

Accessory Organs LIVER A. Secretions B. Functions 1. Digestive function 2. Glycogenesis 3. Gluconeogenesis 4. Glycogenolysis 5. Hematopoiesis in embryo 6. Detoxification 7. Damaged red blood cell removal bile contains pigment by-products of RBC bile pigments eliminated from body with feces brown feces = rusty iron from hemoglobin!

Pancreas a. Anatomy b. Functions c. Digestive Enzyme 1. trypsinogen Acinar cells Islets cells:Alpha, Beta b. Functions c. Digestive Enzyme 1. trypsinogen 2. chymotrypsinogen 3. carboxypeptidase 4. aminopeptidase 5. pancreatic amylase 6. pancreatic lipase These accessory organs secrete their enzymes and a basic fluid into the duodenum of the small intestine

Figure 41.16 The duodenum

Figure 41.18 Activation of protein-digesting enzymes in the small intestine

Small Intestine a. Anatomy 1. size 2. villi 3. lacteals 4. glands b. Functions c. Secretions 1. mucus 2. maltase 3. sucrase 4. lactase 5. peptidase 6. enterokinase

Figure 41.19 The structure of the small intestine

Absorption in the Small Intestine villi microvilli chylomicrons fats, cholesterol, wrapped in protein leave cells by exocytosis lacteals lymphatic system hepatic portal vein

MOUTH What enzymes are made in the pancreas? STOMACH SMALL INTESTINE

Hormonal Control Enterogastrone Gastrin Cholecystokinin secreted in response to the presence of amino acids or fatty acids, causes the gallbladder to contract and release bile into the small intestine and triggers the release of pancreatic enzymes Secretin chyme(acidic pH)enters the duodenum, signals the pancreas to release bicarbonate to neutralize the chyme

Flora of Large Intestines Living in the large intestine is a rich flora of mostly harmless bacteria Escherichia coli a favorite research organism bacteria produce vitamins vitamin K; biotin, folic acid & other B vitamins generate gases by-product of bacterial metabolism methane, hydrogen sulfide

Large Intestines (colon) Reclaiming water used as solvent for various digestive juices ~7L of fluid secreted into digestive tract daily > 90% of water reabsorbed diarrhea = insufficient water absorbed constipation = too much water absorbed

Large Intestine Wall Numerous Goblet Cells

Figure 41.x1 Large intestine

Rectum Terminal portion of colon Feces contain masses of bacteria undigested materials, mainly cellulose roughage or fiber salts appendix

Structural Adaptations reflecting diet have made mammals very successful 1. Dentition

Structural Adaptations 2. Length of Digestive System

Structural Adaptations 3. # of Stomachs

Digesting Cellulose How well you digest cellulose governs life strategy of herbivores COW Can digest cellulose well; not need to eat supplemental sugars GORILLA Can’t digest cellulose well; must supplement with sugar sources, like fruit

Figure 5.8 The arrangement of cellulose in plant cell walls

Figure 41.x2 Termite and Trichonympha Protozoans and Bacteria have enzymes to digest cellulose