EFFECT OF POST - WEANING HEAT CONDITIONING ON IMMUNITY AND HEAT SHOCK PROTEIN 70 GENE EXPRESSION IN TWO STRAINS OF GROWING RABBITS

Abstract

The main objective of the present study was to evaluate the effect of short term Heat Stress on productive performance and some blood parameters in two strains of growing rabbits. A total number of 64 weaned unsexed rabbits (6 weeks of age) were used in this study (32 from each of New Zealand White, NZW, and Local Baladi Black, BB rabbits). They were randomly divided into two experimental groups: a control group and heat stressed one. The latter group was exposed to four hours of heat stress at 36 ± 1 ⁰C and 55 – 60% RH for three consecutive days at 42 days of age. The same manner was applied after six weeks of age (at marketing). After HS exposure, three rabbits from each treatment were used to determine some blood parameters, heat shock protein (HSP 70, 90); Growth performance data were also recorded. Results showed that daily weight gain was significantly increased in heat stressed rabbits than control, while feed consumption was significantly reduced in NZW rabbits, resulting in an improvement in FCR of NZW rabbits than BB. Heat stress (p≤0.05) increased plasma total protein, albumin and Globulin than control group, while A/G ratio was not influenced. Baladi Black rabbits had significantly lower IGF and Corticosterone level compared by NZW rabbits, while T3 hormone level was not significantly affected. HS increased (p ≤ 0.05) IGF and Corticosterone levels. A significant interaction effect between HS and breed was recorded for all studied hormones. Heat shock protein were significantly increased in local BB rabbits compared to NZW ones. It is concluded that it is concluded that early age heat exposure of weaning rabbits could be used as an alternative tool to alleviate the negative impact of heat stress at older age.