Myosin heavy chain (MHC) isoforms in goat muscles and their possible relationships with meat quality have not been fully elucidated. This study characterized the MHC isoforms in different caprine muscles using sodium dodecyl sulphate glycerol gel electrophoresis (SDS-GGE). The relationships between MHC isoforms, calpain systems and meat quality characteristics of different muscles in goats were examined. Four muscles, namely infraspinatus (IF), longissimus dorsi (LD), psoas major (PM) and supraspinatus (SS) were obtained from ten Boer crossbred bucks (7-10 months old; 26.5 ± 3.5 kg, BW). The percentages of MHC I, MHC IIa and MHC IIx in SS, IF, PM and LD were 47.2, 38.3, 32.1, 11.9; 28.0, 42.1, 33.0, 36.4; and 24.8, 19.6, 34.9 and 51.7, respectively. IF and SS had higher levels of calpastatin, total collagen and insoluble collagen contents than did PM and LD. PM had longer sarcomere length than did other muscles. LD had higher collagen solubility, troponin-T degradation products and glycogen content than did other muscles. These results infer that variable fiber-type composition could account partially for the differences in the physicochemical properties of goat muscles.
The effects of organic Zn-L-selenomethionine (Zn-L-SeMet) at 0.3 ppm on carcass composition, meat characteristics, fatty acid composition, glutathione peroxidase activity, and ribonucleotide content were compared against the commercial inorganic sodium selenite (Na-Se) and the combination of the two, in commercial broilers. A total of 540 one day-old chicks were assigned at random to 3 dietary treatments : i) commercial inorganic selenium as control or T1, ii) a 1:1 ratio of inorganic and organic selenium as T2, and iii) organic selenium as T3. Carcass composition, meat characteristics, cholesterol content, fatty acid composition, and ribonucleotide content were generally unaffected by treatments. However, discrepancy were significantly observed in glutathione peroxidase activity (GSH-Px) and water holding capacity, with organic selenium showing higher glutathione peroxidase activity (p<0.01) and lower shrinkage loss (p<0.05), respectively. These findings could be explained by the contribution of organic selenium in bioavailability of GSH-Px. However, having conducted in a commercial close house system with sufficient amount of nutritional supplementation, the present study demonstrated little or no effects of organic Zn-L-SeMet on meat characteristics, fatty acid composition, and ribonucleotide content (flavor characteristic) in broiler chickens.