SRINIVASA PRASAD .CH (MAJOR)VASANTHA SESHU KUMARI .IASWANI KUMAR .KSUJANA GONTLA2024-07-062024-07-062023-08https://krishikosh.egranth.ac.in/handle/1/5810211541The objective of the present study was to know the effect of exogenous melatonin administration on physiological, oxidant, antioxidant and cortisol profiles along with expression pattern of MCTs and HSP70 in heat stressed Murrah buffaloes. Fifteen non pregnant adult Murrah buffaloes of 5-8 years of age were selected randomly and divided into three groups Control (n=5), T1 (n=5) melatonin@18mg/50 kg b.wt single administration and T2 (n=5) melatonin@18mg/50 kg b.wt twice at fortnight interval. The blood samples were collected by jugular vein puncture into EDTA and serum vials at weekly intervals for a period of seven weeks during study period. Oxidant, antioxidant, cortisol profiles were estimated. The physiological parameters and THI were also recorded during the period of study. THI of the present study recorded was >80 except during 5th week (THI-78). RT, RR and PR were significantly (p<0.05) lower in melatonin treated buffaloes compared to control. Significant decrease (p<0.05) was observed in RT of T2 compared to T1 while no significant (p>0.05) difference was found in RR and PR in between these groups. MDA and cortisol levels were significantly (p<0.05) decreased in T1 and T2 compared to control, while significant (p>0.05) decrease was observed T2 compared to T1. Variation in both parameters was observed in all three groups with respect to THI. The mean values of SOD, CAT and GPx were significantly higher (p<0.05) in both treatment groups compared to control, with highest values obtained (p<0.05) in T2 among all three groups. The mRNA expression of MCT 1, 2 and 8 were significantly (p<0.05) downregulated in melatonin treated groups compared to control. HSP70 expression was upregulated in treatment groups compared to control. No significant (p>0.05) difference in expression of MCT1 and HSP70 was observed between T1 and T2. The expression of MCT2 and MCT8 was significantly (p<0.05) higher in T1 than T2. In conclusion, the present study demonstrated the effective role of melatonin in ameliorating heat stress which is evident through the study on various heat stress markers like physiological parameters, estimation of oxidant and antioxidant enzyme activity, estimation of stress hormone cortisol and gene expression studies on monocarboxylate transporters MCT 1, 2 and 8 along with HSP 70. Hence, we can conclude that melatonin could be effective in ameliorating heat stress in buffaloes.EnglishThesis