Performance response of doe rabbits to Toyocerin® (Bacillus cereus var. Toyoi) supplementation.

The efficacy of Toyocerin® was evaluated on doe rabbit performance. Two isonutritive diets were formulated corresponding to 2 levels of Toyocerin®: 0 (diet T1) and 200 mg (diet T2) of Toyocerin®/ kg of feed. Two experiments were conducted to evaluate the efficacy of Toyocerin® on rabbit doe performance in two different experimental periods of twelve and six months, respectively. Thirty-eight breeding cages were assigned to each treatment. No interaction was found between dietary treatment and experimental period. As a consequence, the results of the two trials were treated as a whole. Inclusion of Toyocerin® shortened interval from parturition to effective mating (15.0 vs 10.4 d, P = 0.05) and between parturitions (47.0 vs 42.2 d, P = 0.05) and tended to improve litter size at weaning (by 9.9%, P = 0.09). Consequently, numerical productivity increased from 59.6 to 71.2 weaned rabbits per cage and year (P = 0.01). Litter weight at weaning (25 d) also tended to be higher for diet supplemented with Toyocerin® (3673 vs 3952 g, P = 0.10). As treatment had no effect on daily feed intake (370 g as an average) of rabbits does during lactation, feed efficiency (kg of weaned rabbits per kg of feed intake) increased (P = 0.01) from 0.272 to 0.314 with Toyocerin® supplementation. Treatment did not affect doe body weight at parturition or at weaning, the mortality of rabbit does and the mortality of young rabbits during lactation. These results suggest the interest of the inclusion of 200 ppm Toyocerin® in the diet of lactating rabbit does to reduce parturition interval and increase feed efficiency and numerical productivity.