Influence of age at weaning on caecal content characteristics and post-weaning performance and health of rabbits

This study chiefly aimed to ascertain the effect of age at weaning on caecal content characteristics, post-weaning performance and health of rabbits. A secondary aim was to study the effect of dietary restriction on performance and health of rabbits. After delivery, 30 litters of 8 pups each, were housed in separate cages. Fifteen litters were weaned 24 days from birth (group W 24) while the other 15 were weaned at 28 days (group W28). After weaning, 53 rabbits of group W24 and 56 of group W28 were fed ad libitum (group LIB), while 53 rabbits of group W24 and 57 of group W28 were restricted (group RES). All the rabbits were kept in individual cages. Fourteen other rabbits of groups W24 (7 fed ad libitum and 7 restricted) and 7 of group W28 were sacrificed to obtain data regarding caecum weight and caecal content. Age at weaning affected neither the state of health nor the final live weight. In comparison with those of group W28, the rabbits weaned at 24 days had a lower daily gain until 35 days of age but gain was higher subsequently From the 28th day., however, the feed intake and the feed conversion ratio of the group W24 rabbits were always better than those of W28. The restricted diet until 42 days resulted in a lower weight both at 42 days (1,078 vs. 1, 164 g) and at 70 days (2,192 vs. 2,294 g). Indeed, from the 42nd day, despite receiving feed ad libitum the rabbits of the restricted group continued to ingest less feed (120.8 vs. 127.2 g) than those of the ad libitum group, and had a slightly lower daily gain (39.8 vs. 40.3 g). The measurements carried out on the caecum highlighted significant differences among the groups in caecal content (33.1 vs. 31.7 vs. 25.3 g respectively for groups W24LIB, W28 and W24RES), for total volatile fatty acids (53.2 vs. 50.6 vs. 44.5 mmol/l respectively for groups W24LIB, W28 and W24RES) for ammonia (7.0 vs. 7.2 vs 8.8 mmol/l respectively for groups W24LIB, W28 and W24RES), for propionate (5.7 vs. 6.3 vs. 8.1% respectively for groups W24LIB, W28 and W24RES) and for propionate/butyrate (0.33 vs. 0.36 vs. 0.49 respectively for groups W24LIB, W28 and W24RES).