EFFECTS OF BREED, PROBIOTIC AND THEIR INTERACTION ON GROWTH PERFORMANCE, CARCASS TRAITS AND BLOOD PROFILE OF GROWING RABBITS

This study was performed to investigate the effects of breed, probiotic (as growth promoter agent) and their interactions on growth performance traits, carcass traits and serum biochemistry of growing rabbits from 5 to 13 weeks of age. A 2 × 5 factorial design experiment was performed including two rabbit breeds: New Zealand White (NZW) as forgin breed  and Baladi Black (BB) and five treatments of probiotics. Seventy five growing rabbits with in breed were divided into 5 treatments (15 rabbits in each) were fed on the basal diet and treated  as follows; the first group was untreated with probiotics (T₁), the second group was given a dose of 1 ml of Bifidobacterium bifiduim fresh culture suspension containing 1×10⁷ CFU (T₂), the third group was given a dose of 1 ml of Lactobacillus acidophilus fresh culture suspension containing 7×10⁶ CFU (T₃), the fourth group was given a dose of 1 ml of bacterial mixture (Bifidobacterium bifiduim and Lactobacillus acidophilus) fresh culture suspension containing 3.5 × 10⁷ CFU (T₄) and the fifth group was given a dose of 1 ml of Saccharomyces cerevisiae  (T₅), in each group. The results showed that the live body weight, body weight gain and relative weight gain  of growing rabbits were significantly (P<0.05 or 0.001) affected with breed types at the most of the experimental periods studied. Breed type was insignificantly affected on feed intake during all the experimental periods, except that only significant (P<0.01) effect, during the period of 5-7 weeks of age. Breed type significantly (P<0.05, 0.01 and 0.001) affected on feed conversion ratio during the periods of 5-7, <9-11, <11-13 and 5-13 weeks of age. However, breed type significantly (P<0.001) affected all blood components studied where BB rabbits generally recorded the higher values of RBC count, WBC count, hemoglobin, hematocrit, total protein, albumin and liver enzymes (ALT and AST) than the NZW rabbits. Breed type had a significant effect (P < 0.001) on all studied carcass traits, except carcass and dressing percentages. In general, probiotics treatment groups were significantly (P<0.01 or 0.001) affected on rabbits live body weight at most experimental periods. All probiotic treatments increased significantly live body weight as compared with control group. All probiotic treatment groups significantly (P≤0.05 or 0.001) affected on feed conversion ratio. In general, probiotic treatments improved significantly (P≤0.05 or 0.001) feed conversion ratio. Probiotics treatments affected significantly (P<0.001) on all blood components studied, except globulin level. Moreover, most probiotic treatments were increased significantly (P<0.001) carcass traits studied as compared with control group. Interaction between breed type and kind of probiotics treatments were insignificantly effected on growth performance of rabbits at all the experimental periods studied.