Effect of dietary supplementation with arginine and glutamine on the performance of rabbit does and their litters during the first three lactations

The aim of this work was to study whether the dietary supplementation with arginine (Arg) and glutamine (Gln) or the combination of both influence the digestibility, body composition, and reproductive performance of rabbit does during the first three parturitions. A Control diet containing 29.8 g nitrogen (N), 313 g aNDFom per kg DM and 1.85 g digestible N/MJ digestible energy (DN/DE) was formulated, and another 3 diets were obtained by adding (g/kg) 4 Arg, 4 Gln and a mixture of 4 Arg and 4 of Gln to the Control diet. Eighty nulliparous rabbit does were randomly assigned to the diets (20/diet) before the first insemination. After each parturition litter size were homogenized within each treatment and does inseminated 11 d later. Chemical composition and energy content of rabbit does and their performance, litter growth and milk production were measured between birth and weaning (25 d) along three parturitions. Amino acid supplementation increased the DN content (P = 0.015) and tended to increase the DN/DE ratio compared to Control group (P = 0.077) leading to an increase of digestible N intake during lactation (P = 0.004). In this period, Gln group had a higher DE intake compared to Control and Arg + Gln groups (P = 0.038). Total number kits born per litter tended to increase in rabbit does supplemented with Arg and Gln, compared to Control and Arg + Gln groups (P = 0.095), but no effect of treatments on the number of weaned rabbits was observed (P = 0.15). Single supplementation of Arg and Gln increased the weight of the litters at 20 and 25 d respect to Control and Arg + Gln groups (P ≤ 0.021). Amino acid supplementation did not affect the milk production (P = 0.16), although it was positively correlated with the DE and DN intake (P < 0.001). There were no significant effects of treatments on body weight, chemical composition and energy content of rabbit does, but does supplemented with Arg or Gln tended to have a higher body energy content at the third insemination and at weaning than those from Control and Arg + Gln groups (P ≤ 0.099). Amino acid supplementation did not modify the replacement rate of rabbit does. In conclusion, the single supplementation of Arg and Gln had a positive effect on the weight of litters at weaning and litter size at birth, but no additive effect was observed for the combined supplementation of Arg and Gln.