Energy metabolism in the digestive tract and liver of cattle: influence of physiological state and nutrition

摘要: Major functions of portal-drained viscera (PDV) and liver cattle include absorption digestion products modification the body's supply intermediary metabolites. The disproportionately high metabolic rate PDV (7-13% body tissues) is exemplified by their oxygen uptake (40-50% whole body). Extensive metabolism glucose, volatile fatty acids amino modulates nutrient from diet such that most responses to or physiological state are a function level intake. Similarly, blood flow through highly correlated with energy intake across range weight, composition. Most common dietary in metabolite changes ammonia acids, which emphasize strong energy: nitrogen interrelationship rumen subsequently rest body. (tissue series PDV) removes glucose precursors its as part gluconeogenesis, detoxification urea synthesis. also alters amounts proportions supplied PDV. Accountable percentages metabolizable net include: organic 41-59%; 5-13%; heat (from uptake), 11-22%.