ABSTRACT
This study was conducted to evaluate the effect of dietary chromium picolinate on heat stressed NewZeland White rabbit [NZW] bucks. Forty five NZW rabbit bucks were used in this study and divided into 3 equal groups. The first group was kept in an ambient temperature of 18 +/- 0.5 °C and relative humidity [RH] of 62 +/- 0.5% corresponding to the thermo neutral zone of this species and kept as control normal group. While the second and third groups were exposed to heat stress by establishing an ambient temperature of 35.5 +/- 0.5 °C and relative humidity of 68 +/- 0.5% for 5 hours / day for 3 consecutive days. The second group was kept as heat stressed group, while the third group was given a diet supplemented with chromium picolinate 1200 microgram/kg diet. Whole blood and serum samples were collected from all groups just after heat termination, 1, 3 and 7 days post heat stress. The results of this study revealed that heat stress [HS] elicited significant decrease in body weight in addition to significant increase in rectal temperature and respiration rate and significant decrease in body weight. HS produced significant decrease in red blood cell count, hemoglobin concentration, packed cell volume, total leukocytic count, lymphocytes and monocytes beside significant increase in heterophil and heterophil / lymphocyte ratio. Moreover, HS elicited significant decrease in serum total proteins, albumin and globulin in addition to significant increase in serum urea, creatinine and glucose. Also, HS lead to significant increase in serum Cortisol besides significant decrease in serum thyroid hormones. Regarding the effect of HS on antioxidant status, HS lead to significant increase in serum malondialdehyde [MDA] concentration with significant decrease in serum concentration of antioxidant vitamins [E, C and A] and trace elements [Iron, Zinc, Copper and chromium]. Chromium supplementation restored the abovementioned parameters towards the normal control values. It is concluded that chromium picolinate supplementation 1200 microgram/kg can be considered protective management practice in rabbit diet, alleviating the detrimental effects of HS