Comparative evaluation of physio-hematological, antioxidant and hypoxia associated gene expression responses in cattle breeds adapted to hot semi-arid environment and cold Arid Trans-Himalayan region of Leh-Ladakh.

In the present study, physiological, hematological, antioxidant and gene expression pattern were compared between Ladakhi cattle from cold arid Trans-Himalayan region of Leh-Ladakh and Sahiwal cattle from hot semi-arid environment in the state of Haryana. The physiological parameters like rectal temperature, respiration rate and skin temperature recorded in Ladakhi cattle were significantly (p < 0.05) on lower side as compared to Sahiwal cattle. High altitude adapted Ladakhi cattle recorded relatively higher values of hemoglobin (11.40 ± 0.25), red blood cells (6.81 ± 0.14), packed cell volume (34.8 ± 0.85), while lower values of lymphocyte (4091 ± 222) and white blood cells (8727 ± 229). In addition, Ladakhi cattle depicted significantly (p < 0.05) higher level of antioxidant capacity. Ferric reducing antioxidant power (FRAP) (240 ± 9), 2,2-diphenyl-1-picrylhydrazyl (DPPH) (63.82 ± 1.32), reduced glutathione (GSH) (584.1 ± 31.11) values were significantly (p < 0.05) higher while malondialdehyde (MDA) (5.56 ± 0.27) was significantly lower in Ladakhi cattle. The hypoxia related genes such as HIF1A (1.56-fold), VEGFA (2.47-fold), VEGFB (1.78-fold), EPAS1 (2.11-fold), HK2 (2.14-fold), GLUT1 (5.84-fold), ECE1 (1.95-fold), NOS2 (2.39-fold) GR-a (1.94-fold), GPx (2.15-fold), SOD (2.86-fold) and TNF-A (2.30-fold) were expressed at significantly (p < 0.05) higher level in peripheral blood mononuclear cells (PBMCs) of high altitude adapted Ladakhi cattle. On the other hand, HMOX1 (0.218-fold) and genes related to heat stress such as HSP70 (0.370-fold), HSP90 (0.155-fold) were expressed on significantly (p < 0.05) lower level in PBMCs of Ladakhi cattle in comparison to Sahiwal cattle. A panel of stable reference genes (GAPDH, B2M and RPL4) identified in the study were used to normalize the gene expression data. These findings suggest that high-altitude adapted Ladakhi cattle developed distinct physiological, hematological, antioxidant, and gene expression characteristics that enable them to survive and perform at hypobaric hypoxia environments of Leh-Ladakh.