Metabolic adaptation during feed deprivation was determined in five Kamphaengsaen (KPS) and six crossbred Brahman (Crossbred Bra) heifers. All heifers were fed at the rate of 85% of the metabolizable energy requirement for maintenance. At the end of 20 days of restricted feeding, the Crossbred Bra heifers lost more bodyweight than the KPS heifers (12.0 vs. 7.2 kg) (P < 0.05). In both groups of heifers there was a similar depletion of back-fat thickness, however, the loin eye area of the Crossbred Bra heifers decreased more than KPS heifers (8.43 vs. 0.92%; P < 0.05). Feed restriction elevated the rate of lipolysis in adipose tissue, resulting in increased nonesterified fatty acids concentrations in plasma. The Crossbred Bra heifers had a greater serum high density lipoprotein triacylglycerol concentration than the KPS heifers (17.02 vs. 9.53 mg/dL; P < 0.05). This would suggest that the hepatic tissues in the Crossbred Bra heifers exported more triacylglycerols as very low density lipoprotein than in the KPS heifers. During the feed restriction period, the plasma β-hydroxybutyrate concentration for the heifers was elevated; however, Crossbred Bra heifers shown less plasma β-hydroxybutyrate concentration than KPS heifers (242 vs. 326 µmol/L; P < 0.05). This may be due to the difference in very low density lipoprotein secretion between the two groups of heifers. There were significant differences in plasma urea-nitrogen and plasma glucose concentrations (P < 0.05), with the KPS heifers showing less extensive plasma urea-nitrogen concentration and hypoglycemia, whereas the Crossbred Bra heifers had more extensive plasma ureanitrogen concentration and euglycemia. These two metabolites were suggestive of a ketogenic effect on muscle protein catabolism. In conclusion, it was found that the underfed KPS heifers utilized ketone bodies as their energy source, thus limiting body protein degradation, whereas the Crossbred Bra adapted to feed deprivation by exhibiting an auto-regulation mechanism for ketogenesis and broke down body protein extensively to satisfy their demand for glucose.

The aim of this work was to study the influence of different cooking methods (grilling, roasting, boiling, steaming and frying) on cooking loss and lipid oxidation of buffalo meat (Semimembranosus). Cooking induces significantly cooking loss and lipid oxidation (TBARs index) in meat product (P<0.05). When the different cooking methods were examined, grilling method showed lesser extent of cooking loss and higher level of MDA concentration compared to steaming which was observed with higher cooking loss but lower level of MDA concentration (P<0.05). There were no significant differences on cooking loss and MDA concentration among the rest of the cooking methods (P>0.05). The cooking loss was found to be related to MDA level with r= -0.54 (P<0.05). It has been suggested in this study that cooking loss could be possible response to MDA level in buffalo meat product.