Cellulosic Hydrolysis & Fermentation Ruminant Nutrition, Schemes and Mind Maps of Nutrition

Download Cellulosic Hydrolysis & Fermentation Ruminant Nutrition and more Schemes and Mind Maps Nutrition in PDF only on Docsity! Cellulosic Hydrolysis & Fermentation Ruminant Nutrition Phil Myer**, Bryan Reiling*, Nathan Conner*, Taylor Ruth*, Christopher Stripling** *University of Nebraska-Lincoln, **University of Tennessee Funded by a USDA-NIFA-PDAL grant, Award Number 2021-67037-34298, Program A7501. Cullulose – The most ABUNDANT energy source on the face of the planet.  It’s a nearly  unlimited, renewable source of fuel that could be used to propel automobiles if converted  to ethanol, or perhaps more importantly, provide a palatable, wholesome source of protein  that could be used to feed the world, if processed through ruminant animals. NEXT SLIDE 1 • Primary function = ENERGY • Greatest % of balanced diet • What is the difference? • Glucose, Starch, & Cellulose First, let’s talk about carbohydrates.  You know, for humans, things like potatoes, corn, and  noodles (most of which are made from wheat). CLICK – From a nutritional perspective, the primary function of carbohydrate is to provide  energy. CLICK – and for most livestock animals, carbohydrate represents the greatest percentage of  a balanced diet. CLICK ‐‐ Now, glucose, starch, and cellulose are all carbohydrates; but what is the  difference?  I mean we, as humans, can utilize starch, but not cellulose.  Why not? NEXT SLIDE 2 Nutritional Physiology Terminology Digestion • Preparation of food for absorption • Reduction in food particle size • mechanical - chewing • chemical - HCl, bile • enzymatic – lipase, pepsin • microbial Let’s review basic nutritional physiology, as it relates to the ruminant animal and cellulosic  digestion. CLICK – First, what is digestion? CLICK – Digestion is simply the preparation of food for absorption. CLICK – Digestion represents a reduction in food particle size via mechanical, chemical,  enzymatic, or microbial means. NEXT SLIDE 5 Ruminant Digestive System “Pre-gastric fermentation” Mouth - functions to reduce particle size • Initial mastication (chewing) • Rumination (cud chewing) • Regurgitation – caused by reticulum • Remastication • More saliva • Reswallowing The ruminant digestive system, that associated with animals like the cow, goat, or sheep  exhibits pre‐gastric fermentation.  This means the site of microbial digestion and anaerobic  fermentation of cellulose occurs before digesta reaches the small intestine, the place in the  digestive tract where nutrients are absorbed by the body for productive function. CLICK – The cow, however, must prepare the food for microbial digestion.  So, upon grazing,  the cow will initially chew, then swallow the food. Later, she’ll find a shade tree, lay down, relax, and start to ruminate (CLICK).  Rumination,  or “cud chewing” involves (CLICK) regurgitation of food already consumed, (CLICK)  remastication of that food, (CLICK) addition of more saliva, and (CLICK) reswallowing.  Fun  fact … how much saliva is a full‐grown dairy cow capable of producing per day?  Nearly 50  gallons!  Now, that’s a lot of spit! NEXT SLIDE 6 Ruminant Digestive System Reticulum – the “honeycomb” • Forces the “cud” back to the mouth Reticulum The reticulum, nicknames the honeycomb, because of it’s internal structure, as shown on  the right, is responsible for regurgitation, forcing the cud back into the cow’s mouth as part  of rumination. NEXT SLIDE 7 NEXT SLIDE 9 Ruminant Digestive System Omasum – “manyplies”; “Stockman’s Bible” • Absorption of water Omasum The omasum is the 3rd organ of the ruminant digestive tract.  It’s been called manyplies or  the “Stockman’s Bible” because if the organ is extracted and cut open, it looks like “pages  in a book”.   Its function is to resorb water. NEXT SLIDE 10 Ruminant Digestive System Abomasum (true stomach) • Acidic digestion Small and Large Intestines • same as for monogastric Abomasum The fourth compartment of the ruminant digestive system is the abomasum.  It is often  called the true stomach because it is the same as what you and I have.  Like our own  stomach, the abomasum (CLICK) is where acidic digestion occurs. From there, digesta moves into the (CLICK) small and large intestines.  These digestive  organs play the same role in ruminant animals as they do in non‐ruminant animals.  For the  small intestine, that’s enzymatic digestion and absorption of nutrients.  The large intestine  is primarily for storage of undigested food and water resorption. NEXT SLIDE 11 Sources of cellulose • Corn stalks, leaves, and husks (stover) • Grasses, grown as crops • Prairie grasses • Sawdust and woodchips • Yard waste • Any plant! Thus, cellulosic materials that can be fermented would include (CLICK) corn stover, the  stalks, husks and leaves left in the field after harvest of the grain, (CLICK) any grass or  legume grown for crops, (CLICK) prairie or range grasses, (CLICK) even sawdust, woodchips,  (CLICK) or yard waste!  Bottomline, (CLICK) any and all plants represent sources of cellulose. NEXT SLIDE  14 “Loosened” cell wall material (cellulose hemicellulose, lignin) Rumination Pretreat (grinding, heating) Enzymatic Digestion Glucose Growth Sugar  Cane Corn  (grain) Starch Glucose Growth Non‐Ruminant Digestion Cellulosic Material Glucose Microbial Digestion Cellulase Ethanol / VFAs Growth Microbial Fermentation Process for Making Cellulosic Ethanol: Overview Both glucose and starch, which will first be converted to glucose can be converted to  ethanol, or in the case of animals digesting that energy, growth or productive function. CLICK – Regarding the digestion of cellulosic material such as corn stover, we will pretreat  (CLICK) the substance to “loosen” the cell wall material that is encasing the cellulose.  This  would be synonymous with the rumination component of ruminant digestion. CLICK – Then cellulase will be added to break the Beta‐linkage bonds to release the  glucose.  This would be synonymous with microbial digestion in the rumen. CLICK – Finally, the glucose must undergo fermentation to produce ethanol.  This would be  synonymous with microbial fermentation and the production of VFAs that can be absorbed  across the ruminal wall and used for productive function. NEXT SLIDE 15 Step 1: Pretreatment Break down plant cell walls to release cellulose Simulating Rumination Now, relative to your inquiry‐based learning activity.  The production of glucose and  ethanol from cellulosic material.  You must first pre‐treat the substrate.  This will disrupt  the hemicellulose and lignin strands that encase the cellulose. NEXT SLIDE 16 Reflection Questions • Did you observe any changes in glucose concentrations after the enzyme hydrolysis stage? Explain. • Did your results match what you expected would occur? Explain. • Among all samples tested within the class, what biomass treatment produced the most glucose and ethanol? Why? • Among all samples tested within the class, what biomass treatment produced the least glucose and ethanol? • If you were to try this experiment again to produce more ethanol, what would you do differently? Now, let’s reflect upon the experimental results and discuss with your classmates. Did you observe any changes in glucose concentrations after the enzyme hydrolysis stage? Did your results match what you expected would occur? Among all samples tested within the class, what biomass treatment produced the most (or  least) glucose and ethanol? And If you were to do this experiment again with the goal of producing more ethanol, what  would you do differently? NEXT SLIDE 19 Application Questions • What basic scientific principles are associated with rumen fermentation and nutrient utilization? • Given your results, what are the production & potential economic impacts of feed processing on nutrient utilization, feed efficiency, and cost of gain? • Would this be the same for all animal types, or just ruminants? • What are the pros and cons of harvesting and feeding forages of greater maturity to ruminant animals? Application questions you are encouraged to address include … ‐‐What basic scientific principles are associated with rumen fermentation and nutrient  utilization? ‐‐ Given your results, what are the production and potential economic impacts of feed  processing on nutrient utilization, feed efficiency, and cost of gain?  And would this be the  same for all animal types or just ruminants? ‐‐ Finally, what are the pros and cons of harvesting and feeding forages of greater maturity  to ruminant animals? NEXT SLIDE 20 THE UNIVERSITY OF TENNESSEE KNOXVILLE 21