الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
The drastic impacts of heat stress (HS) on rabbit’sfarms cannot be ignored. The goal of this work is to investigatethe effects of chronic heat stress on immune system and on organs function, and to evaluate the alleviating potential of diet supplements of Moringa oleiferaleaf extract (MOE), vitamin (Vit) C, and sodium bicarbonate (NaHCO3) on HS-induced alterations in NZW rabbits. To achieve this goal, a total of 45 growing male NZW rabbits were divided into five groupsand were designed as control (group 1), HS (group 2), HS+MOE (group 3), HS+Vit. C(group 4), and HS+NaHCO3 (group 5). HS groups were exposed to high temperatures (4 hours/day for 6 weeks), while treatments were given in drinking water during experiment period. Levels of blood cortisol and leptin, IL-1β, TNF-α, IFN-γ, and IL-10 were assayed using ELISA technique, while adrenaline wasassayed calorimetrically. Expression of HSP70, FOXP3, T cell receptor (TCR) γ and δ, lysozyme mRNA was tested using real-time (RT)-PCR, while HSP70 protein expression was tested using western blotting in liver and kidney tissues. Expression of lysozyme mRNA as well as activities of lysozyme, complement and antioxidants were assayed. Infiltration of NK (CD56+) cells, and regulatory T cells (Treg; CD25+) were tested using immunohistochemistry (IHC). Serum markers of liver damage (ALT & AST) and kidneydamage(urea & creatinine) were assayed calorimetrically, while body weight gain (BWG), feed intake (FI), and feed conversion ratio (FCR) were calculated. Moreover, the histopathological changes of liver and kidney as well as mortality rate (MR) of experimental animals were investigated. Data showed increased levels of cortisol, adrenaline, leptin, IL-1β, IFN-γ, TNF-α, ALT, AST, urea and creatinine but decreased IL-10 in the HS group. Increased expression of HSP70 on both mRNA and protein levels was associated with increased NK and γδ T cells versus decreased Treg cell infiltration in liver and kidney tissues of the HS group. Beside decreased lysozymeand antioxidant activities versus increases in both complement activityand MR. In the same group, BWG was decreased, while FCR was increased with respect
Summary and Conclusion103to the control group. Histological investigation showed an increase in inflammatory reactions.Whereas, all treatments used in this study could reverseHS-induced effectssignificantly and restore normal levels. In conclusion, MOE, Vit. C and NaHCO3can be added to rabbit diets for the relief of HS-induced symptoms.In Conclusion:In conclusion, HS was found to cause negative economic effects resulting from poor rabbit health including decreased growth performance and organ (liver and kidney) dysfunctions leading to increased mortality rate. This was due to decreased antioxidant lysozyme and complement activities combined with increased levels of stress hormones, leptin,and inflammatory responses including highly infiltrated NK and γδ T cells which play a major role in cytotoxicity. Supplementation of MOE, Vit. C and NaHCO3to rabbits exposed to HS generally ameliorated HS effects.