No abstract

This study was conducted to evaluate the e ects of adding methionine (Met) to low-protein diets and subsequent re-feeding on the growth performance, serum lipid profile, body composition and carcass quality in male broiler chicks during days of age. During the starter-grower period (days of age),

ABSTRACT:This study was conducted to compare the effect of source of methionine (Met) in broken ricesoybean diet on performance, blood biochemistry, and fermentation characteristics in weaned pigs. Forty-eight male crossbreed pigs (BW 11 ± 0.1 kg) were randomly allocated to three groups with four replications in a completely randomized design. The experimental diets were: (1) basal diet without methionine (Control; total sulfur amino acids (TSAA) 0.60%); (2) basal diet supplemented with dl-methionine (DLM) (TSAA 0.76%); and (3) basal diet supplemented with dl-2-hydroxy-4-(methylthio) butanoic acid (LMA) (TSAA 0.76%). Supplementation with DLM and LMA improved growth performance of piglets and decreased blood urea nitrogen and increased serum albumin (P < 0.01). The population of Lactobacillus spp. in the caecum was decreased by both DLM and LMA supplementation (P < 0.05). Succinic acid concentration in the caecum of pigs fed the DLM diet was greater than that of LMA group (P < 0.05). It can be concluded that LMA can be used as a good source of Met (88% bioefficacy, weight/weight) in broken rice-soybean diet, although the serum albumin and fermentation characteristics (succinic acid) in the gastrointestinal tract were different.

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.

These results indicate that sex-specific differences exist for several biochemical parameters and cardiac marker proteins in fighting fowl, and that such differences should be considered in interpreting laboratory test results.