Patterns of milk productivity associated with biochemical parameters and expressions of the HSPs and Toll Like genes in dairy buffaloes

The aim of this study was to verify milk productivity associated with biochemical parameters and expression of stress marker genes (HSP70, HSP90?, HSP90?) and immunity (TLR-2 and TLR-4) in dairy buffaloes. For this purpose, 12 buffaloes with an average production of 5.93 liters/day (highest production group, n=6) and 3.46 liters/day (lowest production group, n=6) were evaluated. As a result, the groups did not differ (P>0.05) regarding the biochemical analysis of proteins (4.16% versus 4.61%, p=0.13), lipids (5.80% versus 4.87%, p=0.69), lactose (4.74% versus 4.43%, p=0.83) and cortisol quantification (0.67 versus 0.79, p=0.12). The somatic cell count (106.4 versus 139, p=0.36) was within the normal range, indicating the absence of an inflammatory process in the breasts. Relative quantification was higher in the lower yield group compared to the higher yield group (P<0.05) in all genes studied: HSP70 (0.96 versus 0.58, p=0.02), HSP90? (0.98 versus 0.03, p=0.003), HSP90? (0.95 versus 0.48, p=0.03), TLR-2 (1.02 versus 0.16, p=0.008) and TLR-4 (1.26 versus 0.07, p=0.007). Furthermore, Pearson's linear correlation test indicated a negative association between production and expression of HSP90? (r=-0.89, p=0.0001), HSP90? (r=-0.66, p=0.018), TLR-2 (r=-0.72, p=0.001) and TLR-4 (r=-0.67, p=0.01). Despite the difference in production between the groups, milk quality did not differ, nor did cortisol levels, suggesting the absence of physiological stress. However, according to the negative association identified, the higher the daily milk production, the lower the expression of stress and immunity marker genes, suggesting that stress at the cellular level impairs milk production in buffaloes.