THE EFFECT OF SALBUTAMOL ADMINISTRATION ON PERFORMANCE, SOME BLOOD PARAMETERS AND SKELETAL MUSCLES HISTOLOGY OF NZW RABBITS

An experiment was conducted to evaluate the effect of supplementing a beta- adrenergic agonist drug (salbutamol) on growth, carcass traits and some physiological parameters in New Zealand White (NZW) rabbits. A total number of 36 unsexed 6-week-old rabbits, of a similar initial live body weight (LBW) were randomly allotted to 4 treatment groups; each of which was subdivided in to three replicates of three rabbits each. Group 1 (control) was fed a basal diet while groups 2, 3 and 4 were fed the same basal diet but injected (once/week) with salbutamol at doses of 100, 200 and 300 µg/kg LBW, respectively, for 8 weeks.
During the whole experimental period (6-14 weeks of age), salbutamol administration had no adverse effect on growth performance or carcass traits, with slight significant increase in kidney percentage for rabbits injected with a salbutamol dose of 300 µg/kg LBW. Blood plasma levels of glucose, triglycerides, total protein, albumin, globulin and T4 were not affected by salbutamol injection while creatinine and urea N concentrations were inconsistently lower in the salbutamol-treated rabbits than those of the control group. It was observed that salbutamol injection led to a significant increase in blood plasma levels of IGF-I and had a hypocholesterolemic effect compared with the control rabbits. Rabbits injected with 300 µg of salbutamol/kg LBW exhibited significantly higher blood hemoglobin concentration compared with that of the control group but other doses of salbutamol had no effect. The activity of blood plasma CPK was significantly lower with a dose-dependent trend to some extent, in the salbutamol-treated rabbits compared with that of the control group. Also, rabbits injected with 100 or 300 µg salbutamol/kg LBW showed significantly lower activities of LDH in blood plasma compared with that of the control group; however, activities of ALT and AST were not affected by salbutamol injection. On the other hand, rabbits injected with 100 µg salbutamol/kg LBW recorded significantly higher blood plasma level of T3 compared with that of the control group but other doses of salbutamol had no effect. The histological examinations indicated that salbutamol injection could improve the growth of skeletal muscles in rabbits.
Thus, it can be concluded that salbutamol injection in NZW rabbits at a dose of 100 µg/kg LBW has beneficial effects on their growth performance, muscle development and metabolic functions.