Expression of Myostatin (Mstn) and Myogenin (Myog) Genes in Zi And Rhine Goose and Their Correlation with Carcass Traits

An Origanum majorana Leaf Diet Influences Myogenin Gene Expression, Performance, and Carcass Characteristics in Lambs

Myogenin is a protein in the myogenic regulatory factor family that plays an important role in determining carcass and meat traits and is vital for the growth and development of livestock muscles. The objective of this study was to determine the impact of Origanum majorana leaf (MOL) on the myogenin gene expression of lambs. Twenty-four male Kermani lambs were used in a completely randomized design using two experimental groups (0% Origanum majorana L. = MOL0 and 4% Origanum majorana L. = MOL4). Final weight, average daily gain, hot and cold carcass weight, feed conversion ratio, empty body weight, hot and cold dressing percentage, the weight of the shoulder, loin, leg, and lean meat, and the lean/bone ratio were measured. A standard kit was used for extracting total RNA from the loin, leg, and shoulder muscles of the lambs’ tissues. The cDNA was synthesized, a real-time PCR was performed, and the obtained data were analyzed. The results of this study showed that the effect of MOL4 on dry matter intake is not significant. The MOL4 diet increased final weight by 8.22%, average daily gain by 28.57%, hot carcass weight by 11.38%, cold carcass weight by 13.43%, feed conversion ratio by 31.03%, empty body weight by 9.38%, hot dressing percentage by 2.92%, cold dressing percentage by 3.75%, shoulder weight by 56.70%, loin weight by 8.98%, leg weight by 10.90%, lean meat weight by 14.62%, and the lean/bone ratio by 2.85% (p < 0.05) compared to the MOL0. Along with adding MOL4 in the lambs’ diets, in comparison with MOL0, there was higher expression of myogenin in the loin (3.5 times), leg (3.9 times), and shoulder (3.6 times) muscles of the lambs. Due to the fact that adding Origanum majorana to the diet of the lambs enhanced the expression of the myogenin gene in the loin, leg, and shoulder muscles and increased parameters related to growth, it can be used to improve the parameters related to growth and to increase myogenin gene expression in the muscle of lambs.

Effects of Chinese yam Polysaccharides on the Muscle Tissues Development-Related Genes Expression in Breast and Thigh Muscle of Broilers

This experiment was conducted to evaluate the effects of dietary Chinese yam polysaccharides (CYP) on myogenic differentiation 1 (MYOD1), myogenin (MYOG), and myostatin (MSTN) mRNA expression of breast and thigh muscle tissues in broilers. A total of 360 (1-day-old, gender-balanced) crossbred broilers chicks with similar body weight (BW) were randomly distributed into four groups, with three replicates in each group and each replicate included 30 broilers. The feeding trial lasted for 48 days. Experimental broilers were fed 0.00 mg/kg basal diet (control group), 250 mg/kg, 500 mg/kg, and 1000 mg/kg CYP, respectively. The results showed that CYP250 and CYP500 groups had higher thigh muscle percentage (TMP) compared to the control group (p < 0.05). Meanwhile, the expression of MYOD1, MYOG mRNA in breast muscle tissues of CYP500 and CYP1000 groups was higher (p < 0.05), and the expression of MSTN mRNA in thigh muscle of CYP250, CYP500, and CYP1000 groups was lower than that of the control group (p < 0.05). In addition, there was no significant difference in the expression of MYOD1 mRNA in the thigh muscle tissue of each group (p > 0.05). Bivariate correlation analysis showed that the expression levels of MYOD1, MYOG, and MSTN mRNA in the thigh muscle tissue of broiler chickens in the CYP500 group were positively correlated with TMP. However, the expression of MYOG mRNA in thigh muscle tissue of the CYP1000 group was negatively correlated with TMP. In general, this study indicated that appropriate dietary CYP supplementation influenced the growth and development of thigh muscle tissue in broilers by altering TMP and muscle tissue development-related genes expression. Therefore, CYP could be used as a potential feed additive to promote the development of muscle tissues in broilers.

Exploring the impacts of different fasting and refeeding regimes on Nile tilapia (Oreochromis niloticus L.): growth performance, histopathological study, and expression levels of some muscle growth-related genes

The current study investigated how different fasting and refeeding regimes would impact Nile tilapia growth performance, histopathological examination, and gene expression of myostatin, myogenin, GH, IGF-1, and NPYa. Nile tilapia fish (n = 120) were randomly allocated into four groups, including the control group fed on a basal diet for 6 weeks (F6), group A starved for 1 week and then refed for 5 weeks (S1F5), group B starved for 2 weeks and then refed for 4 weeks (S2F4), while group C starved for 4 weeks and then refed for 2 weeks (S4F2). Fasting provoked a decrease in body weight coincided with more extended starvation periods. Also, it induced muscle and liver histological alterations; the severity was correlated with the length of fasting periods. Gene expression levels of GH, MSTN, MYOG, and NPYa were significantly increased, while IGF1 was markedly depressed in fasted fish compared to the control group. Interestingly, refeeding after well-planned short fasting period (S1F5) modulated the histopathological alterations. To some extent, these changes were restored after refeeding. Restored IGF-I and opposing fasting expression profiles of the genes mentioned above thus recovered weights almost like the control group and achieved satisfactory growth compensation. Conversely, refeeding following more extended fasting periods failed to restore body weight. In conclusion, refeeding after fasting can induce a compensatory response. Still, the restoration capacity is dependent on the length of fasting and refeeding periods through exhibiting differential morphological structure and expressions pattern for muscle and growth-related genes.

Skeletal muscle and metabolic flexibility in response to changing energy demands in wild birds

Phenotypically plastic responses of animals to adjust to environmental variation are pervasive. Reversible plasticity (i.e., phenotypic flexibility), where adult phenotypes can be reversibly altered according to prevailing environmental conditions, allow for better matching of phenotypes to the environment and can generate fitness benefits but may also be associated with costs that trade-off with capacity for flexibility. Here, we review the literature on avian metabolic and muscle plasticity in response to season, temperature, migration and experimental manipulation of flight costs, and employ an integrative approach to explore the phenotypic flexibility of metabolic rates and skeletal muscle in wild birds. Basal (minimum maintenance metabolic rate) and summit (maximum cold-induced metabolic rate) metabolic rates are flexible traits in birds, typically increasing with increasing energy demands. Because skeletal muscles are important for energy use at the organismal level, especially to maximum rates of energy use during exercise or shivering thermogenesis, we consider flexibility of skeletal muscle at the tissue and ultrastructural levels in response to variations in the thermal environment and in workloads due to flight exercise. We also examine two major muscle remodeling regulatory pathways: myostatin and insulin-like growth factor -1 (IGF-1). Changes in myostatin and IGF-1 pathways are sometimes, but not always, regulated in a manner consistent with metabolic rate and muscle mass flexibility in response to changing energy demands in wild birds, but few studies have examined such variation so additional study is needed to fully understand roles for these pathways in regulating metabolic flexibility in birds. Muscle ultrastrutural variation in terms of muscle fiber diameter and associated myonuclear domain (MND) in birds is plastic and highly responsive to thermal variation and increases in workload, however, only a few studies have examined ultrastructural flexibility in avian muscle. Additionally, the relationship between myostatin, IGF-1, and satellite cell (SC) proliferation as it relates to avian muscle flexibility has not been addressed in birds and represents a promising avenue for future study.