Thesis (M.Sc.) - Cairo University - Faculty of Agriculture - Department of Genetics

The aim of the present study was to evaluate the effects of GH gene polymorphisms on reproduction and growth traits and identify its variability in the rabbits. A total of 218 blood samples collected from rabbits were used to evaluate the allele frequency distribution for GH gene polymorphisms and its association with reproductive and growth traits in rabbits. The samples included 16 rabbits of the different breeds (Middle-Egypt native breed, Gabali Sinai, Baladi Black, Baladi Red and New Zealand White) and 202 rabbits (118 {u2640} and 84 {u2642}) from APRI rabbits. The traits tested were: (1) body weight (BW) at 5, 6, 8,10 and 12 weeks from birth, (2) daily bodyweight gain (DBG), (3) reproductive traits included age at puberty (AP), Kindling interval (KI), litter size at birth (LS), litter weight (LW) at birth, Litter size at weaning (LSW) and litter weaning (LWW), (4) milk yield. For this purpose, DNA was extracted from rabbit blood samples and used in PCR amplification. The c.-78C >T SNP was genotyped by PCR-RFLP using the digestion by restriction enzyme Bsh1236I (BstUI). Association analysis between the GH C >T SNP and body weight, growth and reproductive traits was tested in the rabbits population using SAS program. The heterozygous genotype was associated with heavy weight of rabbits in different ages during the growth period. This increase in weight was significant (P < 0.05) at 8 weeks of age. DBG through 5-8 week interval was significantly associated (P < 0.05) with the T/C genotype. The heterozygous genotype (T/C) exhibited higher values in the DG compared to C/C and T/T genotypes. The estimated dominant genetic effect (d) was significant (P < 0.05) in 8 weeks

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