Regardless of the absence of spinal deformities, vitamin C deprivation in adult-sized Clarias gariepinus challenged the physical integrity and survival of ®sh, inducing changes that greatly resembled those of ®ngerlings of other species. Vitamin C was presumed to be a dietary facilitator, which when deprived in the diet of C. gariepinus, would obstruct intestinal absorption of iron and/or impair its release from the reticulo-endothelial stores. This impaired erythrocyte synthesis led into anaemia (as indicated by lowered levels of red blood cells, haemoglobin and haematocrit). Leukopenia noted in ®sh on a scorbutic (lacking vitamin C) diet suggested functional depression of phagocytic engulfment with increased susceptibility to the deteriorating action of pathogenic agents. Changes in histology included hypertrophy, oedematous separation and telangiectasia of gill lamellae. Shrunken glomeruli, sloughed Bowman's capsules and tubular dilation and distortion were also shown. Shrunken hepatocytes and the occurrence of yellowish ceroid pigments were the concrete histopathological signs in liver. Vitamin C is thus suggested as a potent antioxidant that oers protection against oxidative damage to various ®sh tissues. KEY KEY WORDS

The research was conducted to study the effect of heat stress on blood parameters in indigenous sheep. Nine sheep were divided into three groups which were almost similar in age, sex and weight. Three groups were divided as zero hour (T0), four hours (T4) and eight hours (T8) heat exposure to direct sunlight. During experimental period temperature–humidity index (THI) value was calculated as 27.09 which indicate T4 and T8 groups were subjected to heat stress condition for at least four hours and eight hours respectively every day. The amount of red blood cell (RBC), hemoglobin (Hb%) and packed cell volume (PCV%) were increased significantly (p<0.05) with the increase of heat stress but the amount of white blood cell (WBC) had no significant difference (P>0.05) among the treatment groups. It can be concluded that heat stress had significant changes on some blood parameters in indigenous sheep. DOI: http://dx.doi.org/10.3329/jbau.v12i1.21253 J. Bangladesh Agril. Univ. 12(1): 91-94, June 2014