Quantitative aspects of ruminant digestion and metabolism

Abstract

This book aims to bring together the quantitative approaches concerned with elucidating mechanisms used in the study of ruminant digestion, metabolism and related areas from different contributing practitioners, experts and scientists. A great deal of research had been carried out on the digestive system of ruminants and also led to studies on the peculiarities of metabolism that cope with unusual products of microbial digestion. Quantitative approaches to ruminant physiology and special features of the ruminant digestive system together with topics on the rate of rumen digestion; intestinal transit; digesta flow; digestibility measurement; particle dynamics; rumen microorganisms and functions; gas production; glucose and fatty acid metabolism; protein and fat metabolism; metabolic regulation; mineral metabolism; protein and energy metabolism interactions; growth; lactation; mathematical modelling; feed processing; feed evaluation; calorimetry; and relationship between pasture characteristics and animal performance are discussed. This book will be of significant interest to researchers, animal scientists, nutritionists, veterinarians, animal breeders and students.

Development of a mathematical model to predict pool sizes and rates of digestion of 2 pools of digestible neutral detergent fiber and an undigested neutral detergent fiber fraction within various forages

“…Residual ash-free NDF of the fermented samples was obtained at 0,6,12,24,30,36,48,72,96,120,144,216, and 240 h based on the procedure of Mertens (2002). Observations were taken more often at earlier time points to offset the greater variation that occurs during the first part of the fermentation and digestion of the substrate (Mertens, 2005). We omitted the use of sodium sulfite for the NDF analyses.…”

“…One of the problems in describing digestion kinetics is that residues remaining at any digestion time are a mixture of undigested and indigestible matter (Mertens, 2005). Furthermore, Mertens (1973Mertens ( , 1977 and Mertens and Ely (1979) indicated that overall digestion is better predicted assuming that the pdNDF fraction is the sum of 2 digestible fractions that can be described by 2 first-order functions but with different rate constants.…”

Bioavailability and Bioefficacy of Hemp By-Products in Ruminant Meat Production and Preservation: A Review

“…Overall, hempseed oil has lower ruminal fermentation parameters compared to soybean and canola oil ( Table 6). Total volatile fatty acids (VFA) can be as high as 200 mM just after feeding or decrease as low as 30 mM, however, its normal range is 70-120 mM (112). Low total VFA (37 mM) from hempseed oil could be an indicator of depressed rumen formation.…”

“…These compounds accumulate in cytoplasmic membranes as they are lipophilic thus disrupting methanogen cell membranes (118). Although methane production is important in maintaining ruminal environment redox balance by providing a pathway for the excess pyruvate (112), it decreases the amount of ME obtained from a diet (69), hence, increasing energy required for meat production. The decrease in the concentration of methane produced may reduce atmospheric greenhouse gases and increase feed utilization efficiency as its emissions represent about 10% of gross energy loss from feed intake (120).…”

Multiomics approach reveals metabolic changes in the heart at birth

“…These short-chain fatty acid degradation pathways are formed from nondigestible carbohydrates in the gut microbiome in adults (37). In both humans and sheep, propanoate and butanoate metabolism lead to the production of acetyl-CoA for entry into the TCA cycle, whereas in sheep, propionate metabolism has been shown to stimulate gluconeogenesis (20). Succinate, present in both butanoate and propanoate metabolism, was more abundant in fetal cardiac tissue (Table 1).…”