Effets de la teneur en énergie de l'aliment chez le lapin. Variations en fonction de l'âge des animaux et de la séquence des régimes alimentaires

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Abstract
The effects of diluting the digestible energy content of the feed with wood cellulose in replacement of part of the dietary starch, on the performances of 126 Californian rabbits between 5 and 11 wk of age were studied. Three diets characterized by their different digestible energy contents were used (kcal/kg DM): H [high] = 2930, M [medium] = 2584 and B [basal] = 2352. Three groups of 12 rabbits received these 3 diets ad lib until slaughter at the age of 8 wk (groups B, M and H). Three other groups of 12 received the same 3 diets until slaughter at the age of 11 wk (groups BB, MM and HH). Two groups of 12 animals received either diet H or B until 8 wk and then vice versa (groups HB and BH) up to slaughter at 11 wk of age. In addition, 5 groups of 6 rabbits reared in conditions similar to those of groups BB, MM, HH, HB and BH were used to determine the digestibility of the feeds during the 10th and 11th wk of age of the animals. Growth performances and feed intake were recorded and visceral measurements made in slaughtered animals. The mean intake of digestible energy per day and per rabbit between 5 and 11 wk of age differed only by .+-. 1.5% from the average value (328 kcal) in all groups. The rabbit is able to regulate its energy intake in the long term even when it receives a succession of diets differing by their digestible energy content. The growth performances were not steadily changed either by the energy concentration of the diets or by the feeding sequence. The only significant effect of the experimental treatment on the visceral development, both at 8 and 11 wk, was a 19% increase in the weight of the cecal content after a maximum dilution of the diet without modifying the tissue weight of the various digestive segments. This effect seemed to be due to the influence of the nature of the diluent (purified cellulose) and not to that of the dilution of the digestible energy. The apparent digestibility of N was not affected by any of the experimental treatments.