ABSTRACT
Skeletal muscle growth in livestock impacts meat quantity and quality. Concerns arise because certain feed additives, like beta-agonists, may affect food safety. Skeletal muscle is a specialized tissue consisting of nondividing and multinucleated muscle fibers. Myostatin (MSTN), a protein specific to skeletal muscle, is secreted and functions as a negative regulator of muscle mass by inhibiting the proliferation and differentiation of myoblasts. To enhance livestock muscle growth, phytogenic feed additives could be an alternative as they inhibit MSTN activity. The objective of this study was to establish a systematic screening platform using MSTN activity to evaluate phytogenics, providing scientific evidence of their assessment and potency. In this study, we established a screening platform to monitor myostatin promoter activity in rat L8 myoblasts. Extract of Glycyrrhiza uralensis (GUE), an oriental herbal medicine, was identified through this screening platform, and the active fractions of GUE were identified using a process-scale liquid column chromatography system. For in vivo study, GUE as a feed additive was investigated in growth-finishing pigs. The results showed that GUE significantly increased body weight, carcass weight, and lean content in pigs. Microbiota analysis indicated that GUE did not affect the composition of gut microbiota in pigs. In summary, this established rodent myoblast screening platform was used to identify a myogenesis-related phytogenic, GUE, and further demonstrated that the active fractions and compounds inhibited MSTN expression. These findings suggest a novel application for GUE in growth performance enhancement through modulation of MSTN expression. Moreover, this well-established screening platform holds significant potential for identifying and assessing a diverse range of phytogenics that contribute to the process of myogenesis.
ABSTRACT
Mastoparan-B is a peptide toxin isolated from the venom of Vespa basalis, the most dangerous hornet found in Taiwan. This study is aimed to evaluate the antioxidative activities of several amino acid substitutions on MP-B, and examined the influences of mast cell degranulation and hemolytic activities in parallel with antioxidative activities. The correlations between the biological function and amino acid sequence were assessed. Our study shows original MP-B is a valuable antioxidant at low concentration in competing with nitric-oxide for oxygen molecules and possesses good antioxidative enzyme activities resembled to superoxidase dismutase and glutathione peroxidase. And there are no predominant rates of mast cell degranulation and hemolytic effects in such condition. With proper substitutions, the reducing power, DPPH scavenging activity and glutathione reductase-like enzyme activity of MP-B can increase clearly. The results demonstrate that MP-B analogs are very potential to be applicable antioxidants for other antioxidative usages.
