Growth performance, slaughter traits, blood analysis and immune response of rabbit pure breeds and their crossbreds under high ambient temperature.

This study aimed to investigate the impact of crossbreeding between pure breeds on the performance of growing rabbits raised under high environmental conditions. Records of 185 growing rabbits aged 8 weeks representing four genetic groups (Saudi local, Jabali; imported Spanish V-Line) and their F2 reciprocal crossbreds (¾J¼V and ¼J¾V) were utilized in this experiment. The growth performance, carcass traits, blood parameters and immune response of the different genetic groups were determined. Superior effects of dressing percentage and valuable meat cuts were found in crossbred rabbits (¾J¼V), when the Jabali breed was used as a maternal line in F1 and F2. Compared with local breed (Jabali) and their crossbreds, the growth performance of the imported rabbit breed (V-Line) was less affected under high ambient temperature. Compared with the remaining genetic groups, the imported V-Line rabbits presented the lowest dressing percentage. The crossbreeds (¾J¼V) presented the highest values of carcass weight, percentage of dressing, and cuts of fore and loin parts. There were highly significant differences (P<0.01) between the four genetic groups for all studied blood parameters. Compared with crossbreds, the purebreds recorded significantly greater level of triglycerides. Cellular immunity was sig-nificantly different among the genetic groups after 24 and 72 h. Conclusions. A negative effect was observed of high ambient temperature on growth performance of imported rabbit breed compared to the local breed and their crossbreds. However, an advantage in cell-mediated immunity for crossbred rabbits derived from Jabali does (¾J¼V) was notice in the later time of swelling difference curve. The findings suggest that incorporating the Jabali breed as a maternal line in crossbreeding programs can enhance productive and immunological traits, particularly in regions with challenging climatic conditions.