Performance, health and slaughter traits of group-housed rabbits submitted to different time-based feed restriction programs

Growth performance, health and slaughter traits were measured in 320 crossbreed rabbits housed in 40 open-top pens (8 rabbits/pen) from weaning to slaughter (34–70 d of age) to evaluate the effects of the different feeding programs: AL, ad libitum feeding; DF, daylight access to feed with fast and complete refeeding; NF, night access to feed with fast and complete refeeding; NS, night access to feed with slow and complete refeeding; NI, night access to feed with very slow and incomplete refeeding. In restricted rabbits, the feeding time decreased from 14 to 9 h/d during the 1st week, remained stable (8 h/d) during the 2nd week, and increased from the beginning of the 3rd week according to three refeeding programs: i) fast until ad libitum (+4 h/d until 24 h/d); ii) slow until ad libitum (+1 h/d until 24 h/d); iii) very slow and still restricted until the end of fattening (+30 min/d until 12 h/d). In the restricted rabbits, feed intake (-3.7%) and feed conversion (–5.6%) were lower compared to AL ones (P<0.001) with the minimum values in the NI group. Diet digestibility increased in the restricted groups compared to AL and in the NI group compared to other restricted groups. Mortality was lower in AL rabbits compared to restricted ones (1.6% vs. 9.0% on average; P=0.04), whereas morbidity and health risk index did not change. Slaughter weight (2608 g), dressing percentage (60.2%), and carcass muscularity were not affected by the feeding program. In conclusion, the NI program represented the best strategy to optimize feed efficiency without impairing growth, slaughter results and carcass traits in growing rabbits. The tested feed restriction programs did not succeed in enhancing rabbit health.