Mn-SOD and Cu,Zn-SOD mRNA expression in relation to physiological indices of Sahiwal and Karan-Fries Heifers under different temperature humidity indices

The present study was carried out during October 2007 to July 2008 in five different combinations of maximum temperature (Tmax) / minimum temperature (Tmin) viz. P1: <20 degrees C/<10 degrees C; P2: >20 degrees C/<10 degrees C, P3: >30 degrees C/<15 degrees C; P4: >35 degrees C/<20 degrees C and P5: >35 degrees C/>20 degrees C. The study aimed to investigate the expression pattern of superoxide dismutase enzymes viz. Mn-SOD nnRNA and Cu,Zn-SOD mRNA in relation to physiological responses of Sahiwal and Karan-Fries cattle. Physiological indices revealed no significant breed differences indicating similar levels of heat adaptability. During P1, expression of Mn-SOD was higher in KF than in Sahiwal while during P5, expression of Cu,Zn-SOD was higher in KF than in Sahiwal (p<0.05). Mn-SOD expression in Sahiwal increased with cold stress while Cu,Zn-SOD expression in KF increased with hot stress (p<0.05).