Impact of heat stress on different toll like receptors gene expression in Malabari goats

Abstract

Research efforts are needed to quantify immune responses to environmental stresses in different indigenous goats and these efforts will be of practical relevance to identify an animal with better immune potential in the changing climate scenario. Hence, a study was conducted to establish the impact of heat stress on different toll-like-receptors (TLR) genes expression in lymph node of Malabari goats. The study was conducted with the primary objective of establishing the impact of heat stress on the expression pattern of different toll like-receptors (TLRs) in Malabari goats. The study was conducted for a period of 45 days using twelve Malabari goats. The goats were randomly allocated into two groups: MC (n=6; Malabari control) and MHS (n=6; Malabari heat stress). At the end of study, all 12 animals were slaughtered and their mesenteric lymph node (MLN) tissues were collected for gene expression. Heat stress significantly (P<0.05) down regulated TLR1, TLR4, and TLR6 and significantly increased (P<0.05) TLR2 expression pattern. A negative correlation (P<0.01) was also established between THI and different TLRs except TLR3, TLR7 and TLRIO. Further a strong positive correlation was obtained between THI and TLR2. The results from the study established that Malabari goat breed showed extreme resilience to cope with heat stress in terms of maintaining the innate immune response and this was evident from the non-significant influence of heat stress on the expression patterns of TLR3, TLR5, TLR7, TLR8, TLR9 and TLR10 genes. Further, the study also indicated that TLR1, TLR4 and TLR6 genes were sensitive to the heat stress effects and the significantly lower expression of these genes in MHS group as compared to MC group indicates the partly compromised immune status in this breed. In addition, the significantly higher expression of TLR2 in the beat stress group indicates the reliability of this gene in assessing the immune status of this breed during heat stress exposure.