Enzymatic Assessment of Catabolic Activity of Pregnant and Non-Pregnant Murrah Buffaloes

Liver insult is the common cause of modulation of the levels of various metabolic enzymes and enzyme ornithine carbamoyl transferase (E.C. 2.1.3.3, OCT) is one of the enzymes. It plays an important role in urea cycle and remains localized in the mitochondrial matrix. The appearance of OCT in the blood has a predictive value for the extent of necrosis, however, there is paucity of work to use the metabolic aspect of this enzyme in healthy animals during stress periods. The inevitability of exposure of Murrah buffaloes to extreme temperatures of arid and semiarid tracts, makes the use of this enzyme as an indicator of catabolic activity of the ruminants an appropriate field of investigation to explore adaptive physiological measures of the body and their use in health management and clinical diagnosis. Extreme ambient heat brings about changes in enzymes and metabolites necessary for physiological adjustment in the body. Therefore the present investigation was planned to determine the activities of serum OCT and levels of urea in serum of pregnant and non-pregnant Murrah buffaloes during moderate and hot ambiences. The mean value during moderate ambience was 46.00±1.50 UL⁻¹. The mean value of OCT was significantly (p ≤ 0.05) higher during hot ambience in comparison to moderate mean value. Analysis of variance showed a highly significant (P≤0.01) effect of ambient temperature variation. Higher activity of serum OCT was suggestive of increased catabolic activity due to hot ambience stress. Serum urea level was also higher which confirmed the higher activity of hepatocytes. This was probably due to the fact that mitochondrial oxidative stress can be compensated by the antioxidant defense system linked to urea cycle. Since hot ambience is known to generate free radicals, results of this study can be correlated with the hypothesis that in intact cells, sometimes oxidizing conditions are disturbed leading to decreased levels of mature OCT. Redox conditions influence mitochondrial pre ornithine transcarb amylase import. indicating the role of serum OCT in oxidative stress mechanism. Serum OCT activity and urea levels were significantly (p ≤ 0.05) higher in non-pregnant animals than pregnant animals. This was suggestive of lowered catabolic activity in pregnant animals. It was concluded that this enzyme can be used efficiently to assess catabolic activity in healthy cases during stress periods to help the management of animals in a scientific manner.