Animal Science 1 - Digestion and Nutrition (2) - PDF

Animal Science 1 6.0 - Understand digestive systems and nutritional components Objective 6.01: Compare ruminant, monogastric, and avian systems.  Digestion Definition—the process of breaking feed down into simple substances that can be absorbed by the body h...

Animal Science 1 6.0 - Understand digestive systems and nutritional components Objective 6.01: Compare ruminant, monogastric, and avian systems.  Digestion Definition—the process of breaking feed down into simple substances that can be absorbed by the body https:// courses.ecampus.oregonst ate.edu/ans312/ten/ swine_1.htm Digestive Systems Ruminants Have stomachs that are divided into multiple chambers Digest large amounts of roughages compared to nonruminants Examples: cattle, goats, and sheep Digestive Systems Non-Ruminants Animals that possess a single- compartment stomach Examples: monogastric animals, hind-gut fermenters, and avian species Non-ruminants Monogastric Hind-gut fermenters Avian animals Have a developed cecum Contains specialized Food is chewed, which contains bacteria structures to soften and swallowed, and then to break down the grind food to aid in enters a low-pH stomach. roughage consumed digestion (e.g., crop, proventriculus, and Cannot typically eat and Examples: horses, gizzard) digest as much roughage rabbits, and guinea pigs as ruminants Examples: chickens, turkeys, ducks, and Examples: swine, dogs, companion birds cats, and rodents Digestive system terminology 1. Absorption—process of simple molecules passing through cell membranes of the lining in the small intestine into the blood 2. Amino acids—the building blocks of protein that contain carbon, hydrogen, oxygen, and nitrogen, and they are essential for growth and maintenance of cells 3. Bolus—small mass of feed once swallowed in animals 4. Chyme—partially digested feed that is acidic, Digestive system terminology 5. Enzymes—organic catalyst substances that speed up the digestive process 6. Gastric juice—liquid that contains water, mucus, hydrochloric acid, and digestive enzymes that are secreted by glands 7. Microbes—single-celled organisms that are found in the rumen and reticulum and aid in digestion 8. Peristalsis—involuntary muscular contractions that create wavelike movements to move canal contents Digestive system terminology 9. Prehension—process of grasping feed with lips, tongue, and/or teeth 10.Rumination—process of forcing feed back up the esophagus to be chewed further to increase digestibility of roughages; occurs only in ruminant animals; also known as “chewing the cud” 11.Villi— small finger-like projections in the intestinal wall that increase the surface area and aid in digestive absorption Ruminant Digestive System  Mouth Beginning of digestive tract; includes teeth, tongue, and salivary glands Bites and masticates (chews) food to increase surface area of feed particles Saliva in the mouth stimulates taste and softens and lubricates food. Ruminants swallow food rapidly without chewing food adequately. They then ruminate feed. The tongue guides feed to the esophagus and can also aid in prehension for some species.  Esophagus Muscular tube next to trachea Guides bolus from mouth to the stomach Uses involuntary muscular waves or contractions (peristalsis) In ruminants, reverse peristalsis brings the bolus from the stomach back to the mouth for rumination  Rumen Large white/gray colored sac on the left side of the animal Largest section of the stomach; interior lining resembles carpet The rumen and reticulum make up 85% of stomach capacity. Contains microbes that convert low-quality protein from forages (roughages) into amino acids Ruminants spend 5–7 hours  Reticulum Compartment connected to the rumen on the left side of the animal The interior lining resembles a honeycomb pattern. Takes in liquids that soak food for microbial digestion  Reticulum Cattle often swallow foreign objects such as nails or wire because they eat rapidly and do not use lips to discriminate among food particles. ○ Hardware disease— common term for illness from these foreign objects ○ Prevented by inserting a small magnet into the reticulum  Omasum Round, muscular part of the stomach, with many layers of tissue Contains papillae responsible for grinding and squeezing roughage to remove liquid  Abomasum Elongated sac at the base of the stomach The interior lining is the smoothest of all stomach parts. The only functional portion of the ruminant’s stomach when animals are born https://australiansheepenterprise.weebly.com/digestive- system.html  Abomasum Enzymes and gastric juices are secreted to act on feed particles from concentrates. Contains hydrochloric acid, which stops action of salivary amylase, adds pepsin to act on proteins, and adds gastric lipase to act on fats Muscular walls help churn and squeeze feed, forcing liquids into the  Accessory Organs Liver Pancreas Gallbladder ○ Release digestive juices into the small intestines to aid in digestion.  Small Intestine Long coiled tube, divided into three sections—the duodenum, the jejunum, and the ileum Chyme is mixed with bile, pancreatic juice, and intestinal juice. Intestinal juice is secreted by the intestinal wall and contains enzymes that break down proteins and sugars. Cecum A blind pouch located between small and large intestines Serves little to no function for most ruminant animals  Large intestine Coiled tube shorter in length, but larger in diameter, than the small intestine Divided into the colon and rectum Absorbs water and adds mucus to the undigested feed to form feces Some enzymatic and microbial digestion occurs on any remaining feed. Anus End of digestive tract where waste is excreted Monogastric Digestive System  Mouth Beginning of digestive tract; includes teeth, tongue, and salivary glands Bites and masticates (chews) food to increase surface area of feed particles Saliva in the mouth stimulates taste and softens and lubricates food. Saliva also contains salivary amylase and maltase enzymes to help change some starch to maltose (malt sugar). The tongue guides feed to the esophagus and can also aid in prehension for some species. Esophagus Muscular tube next to trachea Guides bolus from mouth to the stomach with involuntary muscular waves or contractions (peristalsis) Stomach A U-shaped sac connected to the esophagus Enzymes and gastric juices are secreted to act on feed particles from concentrates. Contains hydrochloric acid, which stops action of salivary amylase, adds pepsin to act on proteins, and adds gastric lipase to act on fats Muscular walls help churn and squeeze feed, forcing liquids into the small  Accessory Organs Release digestive juices into the small intestines to aid in digestion. Liver Pancreas Gallbladder  Small intestine Long coiled tube, divided into three sections—the duodenum, the jejunum, and the ileum Chyme is mixed with bile, pancreatic juice, and intestinal juice. Intestinal juice is secreted by the intestinal wall and contains enzymes that break down proteins and sugars. Primary site of nutrient absorption by the villi  Cecum A blind pouch located between small and large intestines Much larger in hind-gut fermenters as it is used to digest roughages Uses microbial action to break down roughages  Large intestine Coiled tube shorter in length, but larger in diameter, than the small intestine; divided into the colon and rectum Absorbs water and adds mucus to the undigested feed to form feces; some enzymatic and microbial digestion occurs on any remaining feed Anus End of digestive tract where waste is excreted Avian Digestion Beak Pecks and takes in feed whole Birds do not have teeth to chew feed. Esophagus Muscular tube Guides food from beak to crop  Crop Oval sac-like structure between esophagus and proventriculus Stores and softens feed from saliva secretions Proventriculus True stomach where gastric acids and enzymes aid in the digestive process  Accessory Organs Release digestive juices into the small intestines to aid in digestion. Liver Pancreas Gallbladder Ceca Unlike other animals, birds have two ceca. “Blind” pouches are located between the small and large intestines. Contain soft, undigested feed  Large intestine Tube-like structure, larger in diameter when compared to small intestines; filled with digested feed Absorbs water and adds mucus to the undigested feed to form feces  Cloaca Enlarged part of digestive tract located just before the vent Digestive and reproductive tracts combine and prepare for excretion of waste or eggs.  Vent External opening and the end of the digestive, urinary, and reproductive systems. Excretes solid (feces) and liquid (urine) waste, and lays eggs (females only). Accessory Organs Accessory Organs Liver Dark brown structure made of several lobes Largest gland in the body, located under the stomach Produces bile that acts on fats Accessory Organs Pancreas Elongated reddish-colored organ that lies against the stomach Produces digestive enzymes that break down feed materials ○ Trypsin—enzyme that breaks down remaining proteins ○ Pancreatic amylase—changes starch that was not processed by salivary amylase into maltose ○ Lipase—acts on fats to convert them into fatty acids Accessory Organs Gallbladder Sac filled with greenish fluid Located on the liver Stores bile that aids in the digestive process Bile is released straight from the liver to small intestines. Horses do not have a gallbladder.