Effect of genotype and feeding plan on growth performance, slaughter results and meat quality of growing rabbits

The present study evaluated the effects of the genotype and the feeding plan, on growth, slaughter results and meat quality of growing rabbits. A total of 336 crossbred rabbits (184 Grimaud, G, and 184 Hyla, H) were divided into 8 experimental groups (42 animals/group) according to a tri-factorial design (2 genotypes ×2 digestible energy (DE) levels ×2 crude protein (CP) levels) and reared from weaning to slaughter (33–76 d of age). Animals were fed with 4 diets obtained by the combination of 2 DE levels (HE; high DE: 10.9 MJ/kg vs. LE; low DE: 9.2 MJ/kg) and 2 CP levels (HP; high CP: 15.9% vs. LP; low CP: 14.4%) during the post-weaning period (33–64 d of age) and then received a unique commercial fattening diet (10.7 MJ DE/kg, 15.0% CP) until slaughter. Compared to H rabbits, G rabbits showed lower live weights (LW) at the beginning of the trial (914 vs. 967 g; p < .001), at 64 d of age (2537 vs. 2647 g; p < .001) and at the end of the trial (3073 vs. 3147 g; p < .01). In the whole trial, daily feed intake (DFI) was lower in G rabbits than in H rabbits (161 vs. 165 g/d; p < .05), whereas daily weight gain (DWG) and feed conversion ratio (FCR) were similar. At slaughter, G rabbits showed a lower full gut incidence than H rabbits (16.2 vs. 17.6%; p < .001), and a higher dressing out percentage (62.9 vs. 61.1%; p < .001). The increase of dietary DE concentration decreased (p < .001) DFI (14%) and FCR (16%) in the post-weaning period. During fattening, the animals previously fed with LE diets showed higher DFI (+7%) and DWG (+15%), and improved FCR (5%) compared to those fed with HE diets (p < .001). In the whole trial period, HE diets reduced (p < .001) DFI (13%) and FCR (10%), without affecting the final LW. The reduction of dietary CP content did not affect growth performance and slaughter results. Meat quality traits (pH, colour indices and shear force) were not affected by the experimental factors. In conclusion, the higher final LW reached by H rabbits may increase the profitability to the farmers, but the economic margin is reduced as compared to G rabbits due to the lower dressing-out percentage. The increase of dietary DE concentration is confirmed as a useful strategy to reduce feed costs and enhance the global efficiency of rabbit farms. The reduction of CP dietary content from 15.9% until 14.4% during post-weaning decreases the nitrogen excretion of rabbit farms and could reduce the feeding costs, depending on the market price of protein sources.