CYTOGENETIC SCREENING OF DIFFERENT BREEDS OF RABBIT FOR GROWTH POTENTIALS IN A WARM HUMID TROPICAL ENVIRONMENT
The study was carried out to determine the x-chromatin status of different breeds of rabbit and their crosses. The genotypes were Newzealand (NZW) x Newzealand (NZW), Dutch Black (DTB) x Dutch Black (DTB), (NZW) x DTB, and DTB x NZW. One hundred and sixty-nine offsprings from the mating were screened. Blood samples were collected with heparin sample bottles fortified with EDTA anti-coagulant via the ear veins and blood smears were made on clean glass slides. They were stained with Geimsa, rinsed in distilled water and air dried. With the aid of microscope, 200 polymorphonuclear neutrophils were examined for the presence of drumstick appendages. The result revealed that the females had the average x-chromatin status of 2.09%, 2.00%, 2.28% and 2.07% for NZW x NZW, DTB x DTB, NZW x DTB and DTB x NZW genotypes respectively while the males had the average x-chromatin status of 0.00%, 0.05% 0.00% and 0.00% for NZW x NZW, DTB x DTB, NZW x DTB and DTB x NZW genotypes respectively. These values were within the normal range of 2.00 – 12.00% for females and 0.00% – 2.00% for males. It was concluded that these animals were free from x-chromatin related physiogenetic problems. The body weight measurement of the rabbits at 4, 8, 12 and 16 weeks of age showed significant differences at (p<0.05) across the genotypes. The linear body measurements of males and female rabbits at 4, 8, 12, and 16 weeks of age showed significant differences at (p<0.05) across the genotypes. From this experiment it could be concluded that the Main crosses ((NZW) x DTB) and the Reciprocal crosses (DTB x NZW) came out better since they explored the advantages of cross breeding and it is advised that farmers should practice cross breeding of rabbits rather than breeding pure lines.