Influence de l'ingestion d'acide caproique sur l'utilisation de l'energie et de l'azote ingeres par le rat en croissance en fonction de l'age des animaux et de la teneur en azote des regimes

Yong male rats of the Wistar CF strain are used to determine the effects of tricaproine intake on energy and nitrogen utilization in diets of animals at two different physiological stages (Experiment I) or when given in rations containing various nitrogen levels (Experiment II). Experiment I is carried out in closed-circuit respiration chambers using indirect calorimetry on rats given balanced diets containing 1.56 mg digestible nitrogen per metabolizable energy (EM) Kjoule (mg Nd/KJ EM). Prepuberal rats (no g liveweight) receiving tricaproine have lower growth maintenance requirements than control animals ( 76 p. roo as against 7 1 p. 1)0.0 Utilization of energy and nitrogen is improved in these animals up to a certain consumption level and then decreases. Puberal rats 2 (20 g liveweight) given tricaproine present very reduced EM growth yields 4 (5 p. 1 00 as against 28 p. 1)0,0 but the apparent low level maintenance requirement leads us to believe that there is a curvilinear relationship between EM and EF (fixed energy). In animals taken at this physiological stage, the use of ingested nitrogen is diminished to a certain consumption level and then improves. Experiment II is done by sacrificing the animals and analyzing the carcasses, following a factorial plan combining 3 nitrogen levels in the diets 2(-.1360 and 5 .13 mg Nd/KJ EM) and 3 tricaproine levels (o, 1 0 or 2 0 p. 1 00 in energy). Energy and ingested nitrogen utilization are improved by introducing tricaproine into the diets, the effect being more evident as the diet is richer in nitrogen. Energy fixed by experimental animals thus increases from to 1 2 p. 1 00 as compared to that fixed by the corresponding control animals (same nitrogen level in diets). Also fixed nitrogen is increased from 2 to m p. 1.00 The amount of energy and nitrogen are significantly increased in rat livers, thus emphasizing the role of the liver in subiects given medium chain fatty acids. The overall effects observed lead us to retain the hypothesis that caproic acid has a particular insulino-secretor effect. De jeunes rats mâles de souche Wistar CF ont été utilisés pour déterminer les effets de l’ingestion de tricaproïne sur l’utilisation de l’énergie et de l’azote des rations d’animaux pris à deux stades physiologiques différents (Expérience I) ou recevant des régimes comportant des taux azotés différents (Expérience II). L’expérience I a été réalisée selon le principe de la calorimétrie indirecte en chambres respirato