Simple Summary Skeletal muscle is the largest tissue and serves as a protein reservoir and energy reservoir in the human and animal body. It also serves as the main metabolic activity site. The formation of skeletal muscle mainly depends on the differentiation and fusion of myocytes and other complex ordered processes; each step is regulated by various factors. In this study, we investigated the expression profiles, functional identification, and regulatory pathways of Delta-like 1 homolog (DLK1) in pigs and myocytes. We found that DLK1 was highly expressed in the muscle tissues of pigs. DLK1 promoted myocyte proliferation, migration, differentiation, fusion, and muscular hypertrophy, but suppressed muscle degradation. DLK1 also inhibited the Notch signaling pathway by regulating the expression of key factors in the pathway, thereby producing a phenotype in which DLK1 promotes muscle development. These findings provide valuable information to improve our understanding of the functional mechanisms of DLK1 that underly myogenesis to accelerate the process of animal genetic improvement. Abstract DLK1 is paternally expressed and is involved in metabolism switching, stem cell maintenance, cell proliferation, and differentiation. Porcine DLK1 was identified in our previous study as a candidate gene that regulates muscle development. In the present study, we characterized DLK1 expression in pigs, and the results showed that DLK1 was highly expressed in the muscles of pigs. In-vitro cellular tests showed that DLK1 promoted myoblast proliferation, migration, and muscular hypertrophy, and at the same time inhibited muscle degradation. The expression of myogenic and fusion markers and the formation of multinucleated myotubes were both upregulated in myoblasts with DLK1 overexpression. DLK1 levels in cultured myocytes were negatively correlated with the expression of key factors in the Notch pathway, suggesting that the suppression of Notch signaling pathways may mediate these processes. Collectively, our results suggest a biological function of DLK1 as an enhancer of muscle development by the inhibition of Notch pathways.

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Functional Identification of Porcine DLK1 during Muscle Development

The gut microbiota (GM) has become recognized as a crucial element in preserving human fitness and influencing disease consequences. Commensal and pathogenic gut microorganisms are correlated with pathological progress in atherosclerosis (AS). GM may thus be a promising therapeutic target for AS. Natural products with cardioprotective qualities might improve the inflammation of AS by modulating the GM ecosystem, opening new avenues for researches and therapies. However, it is unclear what components of natural products are useful and what the actual mechanisms are. In this review, we have summarized the natural products relieving inflammation of AS by regulating the GM balance and active metabolites produced by GM.

https://www.frontiersin.org/articles/10.3389/fmicb.2022.997056/pdf

Natural products against inflammation and atherosclerosis: Targeting on gut microbiota

Influences of ferulic acid on intestinal digestive and antioxidant enzymes, immune, antioxidant gene and tight junction protein expression and microbiota in hybrid grouper (Epinephelus fuscoguttatus♀× Epinephelus polyphekadion♂)

Integrated eco-physiological, biochemical, and molecular biological analyses of selenium fortification mechanism in alfalfa

This study investigated the effects of dietary feruloyl oligosaccharides derived from fermented wheat bran (FOs-FWB) supplementation on carcase traits, meat quality, muscle fatty acid composition, and the expression of lipogenic genes in lambs. In a completely randomised design, 50 Dorper × thin-tailed Han lambs (20.21 ± 3.36 kg) were randomly divided into five treatments with ten replications. The lambs in the control group were fed a basal diet, while those in the experimental groups were fed the basal diet supplemented with 50, 100, 200, and 400 mg/kg FOs-FWB. The shear forces of longissimus dorsi (LD) in lambs fed 50 and 100 mg/kg FOs-FWB were significantly lower than that of the control group (p < .05). Lambs fed with 200 mg/kg FOs-FWB had higher crude protein and lower fat contents in LD muscle (p < .05), the ash content in LD muscle was increased by FOs-FWB supplementation (p < .05). Lambs fed 50 mg/kg FOs-FWB had significantly higher proportions of C18:1n − 9, C20:1, C18:3n − 3, C18:3n − 6 and total n − 3 (p < .05). The proportion of C18:3n − 6 was significantly increased by 100 mg/kg FOs-FWB supplementation (p < .05). Feeding 200 mg/kg FOs-FWB significantly decreased proportions of C14:0 and total saturated fatty acid (SFA), but increased proportions of C18:1n − 9, C18:2n − 6, total monounsaturated fatty acid (MUFA) and unsaturated fatty acid (UFA) to SFA ratio (p < .05). Moreover, increases in the proportion of C22:6n − 3 and total polyunsaturated fatty acid (PUFA) were observed in lambs fed FOs-FWB (p < .05). The relative expression levels of ACC, FAS, and SCD genes in the LD muscle of lambs fed 200 and 400 mg/kg FOs-FWB were higher than the control group (p < .05). Dietary supplementation with 100, 200, 400 mg/kg FOs-FWB significantly increased the relative mRNA expression level of LPL (p < .05). Furthermore, a decrease in the relative mRNA expression level of PPARγ was observed in lambs fed 50 mg/kg FOs-FWB (p < .05). In conclusion, dietary supplementation with FOs-FWB reduced shear force, enhanced intramuscular fat content and PUFAs proportion and stimulated lipogenic gene expression in LD muscle of lambs, especially at a level of 200 mg/kg addition.HighlightsDietary FOs-FWB improved the tenderness of the meat.Dietary supplementation with 200 mg/kg FOs-FWB increased the content of intramuscular fat and PUFAs, as well as the ratio of UFA to SFA.Dietary FOs-FWB affected the expression of genes related to lipid metabolism. 

Carcase traits, meat quality, and lipogenic gene expression in muscle of lambs fed wheat bran feruloyl oligosaccharides

Ferulic acid (FA) is one of a common ingredients in Chinese herbal medicine. FA has the interesting property of promoting growth and improving meat quality in livestock, but the mechanism is not understood. This study evaluated both safety and mechanism of efficacy in zebrafish model. At 15 μg/mL or above, FA led to pericardial oedema and delayed growth in zebrafish embryos. Dietary FA promoted growth and feed assimilation in male adult zebrafish. Genes related to myogenic development (myod1, myog and myf5) were significantly upregulated by FA and muscle fibre width in skeletal muscle was increased. At 20 µg/g, FA significantly increased number of goblet cells in zebrafish intestinal tissue, and gut microbiota composition also changed. Based on 16s rRNA gene sequences, 20 μg/g FA decreased Firmicutes and increased Bacteroides. 20 μg/g FA also stimulated the expression of PPAR-α, a gene associated with fat metabolism, and decreased the expression of PPAR-β and PPAR-γ. These gene expression changes were beneficial to fatty acid synthesis and metabolism and decreased fat deposition. Our overall results indicated that FA can be a safe growth promotor in fish particularly in skeletal muscles.

Chelimuge Qi

Papers

Effects of ferulic acid on muscle development and intestinal microbiota of zebrafish