Feeding behaviour of the growing rabbit fed freely or restricted, and impact on performances and digestive organs

This study aimed to determine how rabbits’ feeding and drinking behaviour was influenced by a feed restriction programme, and how performance and the morphometry of the digestive tract and lymphoid organs were influenced. At weaning (28 d old), 432 rabbits were housed in cages of 6, and allotted to 2 groups according to feed intake level: ad libitum feeding (AL group) from 28 to 72 d old, and feed intake (R group) restricted to 70% of AL intake from 28 till 49 d old, followed by ad libitum feeding from 50 till 72 d old. During the restriction, the R group intake was 36% lower than that of the AL group. When returning to an ad libitum feeding, the R group intake increased by 270%, thus exceeding the AL intake by 26% (P=0.03). The daily weight gain was reduced by 28% for R group during the restriction (40.0 vs. 55.7 g/d; P<0.001), whereas the feed conversion was improved (−11%, 1.86 vs. 2.09; P<0.001). The restriction led to a shorter intestine (−15%, 202 vs. 233; P<0.05) and lighter spleen (−15%, 4.8 vs. 5.9; P<0.05), whereas the number of Peyer patches was not influenced. Most of the growth delays of lymphoid tissues observed at the end of the restriction period in the R rabbits remained until the end of the experiment. The feeding activity of AL rabbits mainly occurred during the dark period (19:00-09:00), with 16% of rabbits eating. The R group strongly and massively started their feeding activity at feed distribution time (8:30-09:00), with 65% of rabbit eating at the start, then 35% still eating half an hour later. Feeding activity of R group remained high for 8 h after the feed distribution, with 28% of rabbits having a feeding activity between 9:30 and 17:00. R group had a higher number of meals (+30%) and drinks (+28%), and a longer meal duration (+30%) compared to AL group. R group consumed 63% of the intake within 6-7 h compared to ad libitum fed rabbits, which spread their intake over 15 h. No changes in social behaviour (access to feed or drinking, resting, aggressiveness) were detected, suggesting that this restriction programme did not impair welfare compared to that of ad libitum fed animals.