The purpose of this research was to compare the growth performance and gene expression variations in three genetic groups of meat rabbits: Alexandria line (AA), V line (VV) and the cross between Alexandria line males and V line females (AV). For the three genetic groups, which were raised under Egyptian environmental conditions, the studied offspring growth traits were individual weight at weaning (WW, 4 wk) and the end of fattening period (MW, 9 wk) and individual daily weight gain. A total number of 22 bucks, 93 does and 792 kits were used in the study. The Gompertz model was periodically used to examine the rabbits’ growth. Five kits per group were used to collect liver tissue samples at marketing age (63 d) for gene expression analysis. According to the findings, the AV strain had a body weight of 135 g more than the AA strain and 277 g higher than the VV strain. The AV strain also showed a decreased daily feed consumption and a better feed conversion ratio. With strong coefficients of determination (R²=0.86), the Gompertz growth curve successfully approximated the growth curves for all genotypes. Our results also revealed that VV strain had the highest myostatin expression, while AA and cross strains had the lowest. In contrast, there was a statistically significant difference in the growth hormone receptor (GHR) and the growth hormone secretagogue receptor mRNA levels between the VV, AA and AV strains, with the cross strain having the highest levels of GHR mRNA expression. These findings suggest that the AV strain reached maturity earlier than the AA and VV strains, which is beneficial for optimising growth and breeding processes. Furthermore, rabbits’ development, metabolism and general health may be affected by hereditary factors that impact gene expression in liver tissues. To better understand the processes at work and their possible uses in breeding programmes, further study is required.
El-latif et al. (Tue,) studied this question.