Weaning caused a decrease in the chymosin content and an increase in the pepsin content of the abomasum. The amount of chymosin per kg of carcass was on the average 2.8-fold lower and that of pepsin 1.9-fold higher in groups S and SL than in group L. The amount of pepsin tended to be higher in group S than in group SL, but only the difference observed (36 %) for the total amount was significant.In group S, the pancreata showed more chymotrypsin, trypsin and amylase activities but less lipase activity than in group L ; the observed differences in these activities per kg of carcass were 32, 49, 70 and 24 %, respectively. The activities of group SL were lower than those of group L for trypsin, chymotrypsin and lipase but higher for amylase (17, 12, 44 and 18 %, respectively). Group SL exhibited lower activities than group S (55, 67, 16 and 44 %, respectively, for trypsin, chymotrypsin, lipase and amylase).Weaning appeared to induce large changes in abomasal and pancreatic enzyme potentialities which exhibited patterns similar to the variations in the amounts of substrate intake. In our experimental conditions, giving a liquid supplement to ruminant calves had a depressive effect on the activities of the enzymes (except chymosin), in the pancreas and the abomasum.Introduction.

Summary -In human, arginine (ARG) induces growth hormone (GH) release, probably via a decrease in somatostatinergic tone. To assess the mechanism by which ARG mediates GH release in pigs, the effects on plasma GH release of ARG ( 1 g/kg body weight, infused between times -15 and -5 min), growth hormone-releasing hormone (GHRH, 2 pg/kg, at time 0 min) and neostigmine, a cholinesterase inhibitor (NEO, 50 arginine / growth hormone-releasing hormone / néostigmine / hormone de croissance / porc

A differenciation between « normal » faeces and caecotrophes can be detected in the distal colon. When

Introduction.

Summary. Effect of the nature of nutrients on blood insulin in the ruminant calf. (D). In calves given the highest quantities of lactose (groups A and B), plasma glucose and insulin levels were very high during the first 6 postprandial hours ( fig. 2). When the intake of lactose was halved (group D), postprandial levels of plasma glucose and insulin increased less and lasted a shorter time. When casein was offered alone (group C), these plasma levels did not increase more than when the dry diet was fed alone (group S in the first trial).In young ruminants as in monogastric animals, glucose absorbed from the small intestine stimulates insulin secretion much more than amino acids ; it also has more effect than volatile fatty acids absorbed from the rumen. Ruminant diets could not stimulate insulin secretion as much as diets permitting the absorption of large quantities of glucose.Introduction.

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fig. 1). It also brought about a decrease in the plasma level of urea (P < 0,01), after the age of 8 weeks ( fig. 2). Thus, the supplements when fed liquid, arrived directly in the abomasum and avoided degradation in the rumen ; so, they were absorbed as glucose, galactose and amino-acids, instead of being fermented as lactic acid, volatile fatty acids and ammonia. The amount of aminoacids absorbed was most likely improved. However, no important increase in the blood levels of most of the essential amino acids was observed, contrary to our previous results where a larger part (52 p. 100) of the protein was fed in liquid form. Even the blood levels of valine, leucine and isoleucine diminished. This is probably due to the great quantity of glucose absorbed with liquid supplements, which would have improved metabolic amino acid utilization. Consequently, growth and feed efficiency were significantly improved with the liquid feeding.

In the growing lamb given maize-base diets containing lupine, a duodenal infusion of lysine + methionine resulted in an increase of nitrogen retention. When the diets contained pea, the infusion of amino acid did not change nitrogen retention.