A Trial Comparing Growing Rabbits Differing in 18 Generations of Selection for Growth Rate Reveals a Potential Lack of Effectiveness in the Genetic Selection Progress.

A total of 338 weaned rabbits (from the R line, selected for post-weaning growth rate) were used to evaluate the response to 18 generations of selection for increased growth rate on rabbit performance. Animals were obtained from two vitrified populations of the R line: R19V, belonging to the 18th generation (n = 165), and R37V, belonging to the 36th generation (n = 173), were allocated in individual and collective pens (178 and 160, respectively). A fattening trial was conducted from weaning (28 d of age until 63 d of age). During the trial, the body weight (BW), daily feed intake (DFI), average daily gain (ADG) and feed conversion ratio (FCR) were weekly monitored. Additionally, mortality and morbidity were daily registered. On days 49 to 53, an apparent faecal digestibility trial was also performed (12 animals per generation). Our results indicate that the generation of selection for growth rate did not affect mortality and morbidity. There were no differences in the diet digestibility according to the generation of selection. Regarding performance traits, R37V animals showed higher global BW (+6.7%;