Effects of Short-chain Fatty Acids, Feeding, Fasting and Type of Diet on Plasma Insulin Levels in Sheep

Abstract

Four experiments with sheep were conducted to study the effects of intravenous injection of short-chain fatty acids, feeding, fasting and type of diet on plasma insulin levels. Injection of propionate, butyrate or glucose was shown to increase insulin secretion with the greatest responses observed after injection of either propionate or butyrate. Although fasting the sheep resulted in decreases in the plasma insulin levels, feeding grain as opposed to feeding only hay produced increases of 50 to 60%. These increases were associated with corresponding increases in propionate and butyrate levels in the rumen. Therefore, since intravenous injection of short-chain fatty acids increases plasma insulin levels and diet affects the concentrations of these fatty acids, the present studies show that diet affects plasma insulin levels in sheep by altering the short-chain fatty acid pattern in the rumen.