Characterization of myosin heavy chain (MYH) genes and their differential expression in white and red muscles of Chinese perch, Siniperca chuatsi

Rumen microbiota regulates IMF deposition in Xizang sheep by activating the PPARγ transcription factor: a rumen-muscle axis perspective

The interaction between microbiota and muscle by the rumen-muscle axis and its impact on sheep meat flavor has received little attention. This study selected Xizang sheep under summer and autumn grazing conditions as models for different rumen bacteria and intramuscular fat (IMF) to attempt to address the current research gap. Specifically, the deposition characteristics of IMF and the expression of lipid metabolism genes in Xizang sheep were determined; 16S rDNA sequencing technology and gas chromatography were used to study the rumen microbiota and its metabolic products, short-chain fatty acids (SCFAs); RNA sequencing was used to identify the transcriptome of the rumen epithelium. Based on the above results, we proposed the hypothesis that the flavor of Xizang sheep meat is regulated by the microbiota-rumen-muscle axis. SCFAs produced in the rumen of Xizang sheep are absorbed by the rumen epithelium under the regulation of the solute carrier family genes (SLC). SCFAs can directly reach muscle tissue through the circulatory system and then activate the expression of the peroxisome proliferator-activated receptor Gamma (PPARγ) gene through the rumen-muscle axis. The expression of fat synthesis genes carnitine palmitoyltransferase II (CPT2), fatty acid synthase (FAS), patatin-like phospholipase domain-containing 2 (PNPLA2), and stearoyl-CoA desaturase 1 (SCD1) is correspondingly upregulated, promoting the deposition of IMF in Xizang sheep and thus affecting its flavor. This study introduces the theory of the microbiota-rumen-muscle axis into the research of the flavor of ruminant animal food, comprehensively elucidating the regulatory mechanism of the flavor of Xizang sheep meat.IMPORTANCEOur study employed a multi-omics approach to reveal how the rumen microbiota regulate muscle lipid metabolism in Xizang sheep through the activation of the PPARγ transcription factor. Importantly, by developing models of Xizang sheep with varying rumen microbial communities and muscle fatty acid profiles, we established the critical role of the microbiota-rumen-muscle axis in determining the flavor of Xizang sheep meat. This finding suggests that modulating the composition of the microbial community could serve as a strategy to improve the flavor of ruminant-derived food products. These insights provide valuable understanding of the complex interactions between rumen bacteria and mutton flavor, offering new approaches for research in this field.

The Role of Twist2 in Myoblast Proliferation, Fusion, and Its Impact on Muscle Structure During the Growth of Chinese Perch (Siniperca chuatsi)

Twist2 plays a pivotal regulatory role in the growth of skeletal muscle across various organisms. Nonetheless, the specific mechanism by which Twist2 governs skeletal muscle function in fish, particularly in the economically significant Chinese perch (Siniperca chuatsi), remains unclear. Within the muscle injury model in Chinese perch, we observed that Twist2 expression was upregulated during the repair phase of fast muscle tissue, exhibiting an expression pattern analogous to that of Pax7. Following the knockdown of Twist2 using Twist2-specific in vivo-siRNA in fast muscle tissues, the expression of myogenic regulatory factors (MRFs) and Myomaker was significantly reduced in the Twist2-siRNA-treated group compared with the control group, whereas no significant differences were observed for Pax3 and Pax7. Furthermore, the diameter of myofibers and the number of nuclei in single myofibers were reduced, and concurrently, the number of BrdU-positive cells (proliferating cells) was significantly reduced in the Twist2-siRNA-treated group. Taken together, this study demonstrates that Twist2 promotes myoblast proliferation and fusion, thereby regulating fast muscle growth in juvenile Chinese perch. These findings provide a clear direction for further exploration of molecular mechanisms underlying skeletal muscle growth in economic fish species.

Comparative Analysis of the Nutritional Composition and Flavor Profile of Different Muscle Parts of Hybrid Abalone (Haliotis discus hannai ♀ × H. fulgens ♂)

This study analyzed the basic nutritional components and amino acid, fatty acid, and mineral composition of hybrid abalone Haliotis discus hannai ♀ × H. fulgens ♂ adductor (AM), transition (TM), and skirt (SM) muscles. The taste characteristics of the muscles were measured via electronic tongue, and the volatile compounds were identified by headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) analysis. Compared to SM, AM and TM exhibited relatively similar basic nutritional compositions. Although SM exhibited the highest moisture content (84.67%), its protein content (only 11.83%) and total carbohydrate content (only 0.19%) were significantly lower than those of AM (20.42% and 4.14%) and TM (19.10% and 4.48%). The ash and fat contents were similar across the three muscle parts. The amino acid composition was consistent across three parts, and AM showed the highest total amino acid content, ratio of essential amino acids, and essential amino acid index. All three muscle parts were rich in polyunsaturated fatty acids, but the content was higher in AM and TM than in SM. The mineral elements were rich in variety, with high K, P, Mg, and Zn contents. Bitterness intensities were lower and umami and richness intensities were higher in AM and TM than in SM. The contents of volatile compounds related to fishy odor were higher in TM and SM than in AM. The results provided a scientific basis for the intensive processing and comprehensive utilization of Haliotis discus hannai ♀ × H. fulgens ♂.

Rosa rugosa promotes muscle hypertrophy and prevents atrophy in C2C12 myoblasts

Skeletal muscle health is essential for both structural and metabolic functions, making muscle atrophy - the loss of muscle mass - a severe health concern. This study evaluates the potential of Rosa rugosa, an edible plant, to enhance muscle hypertrophy and mitigate muscle atrophy in C2C12 myoblasts. Treatment of Rosa rugosa extract (RRE) promoted myogenic differentiation, as evidenced by morphological changes and upregulation of key myogenic regulatory factors critical for muscle formation. Additionally, RRE activated protein synthesis pathways while suppressing protein degradation pathways. In an inflammatory cytokine-induced muscle atrophy model, RRE preserved myogenic differentiation and inhibited protein breakdown. These findings suggest that RRE fosters an anabolic environment conducive to muscle preservation, underscoring its promise as a functional food ingredient for supporting muscle health.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10068-024-01803-w.

Comparison of muscle structure and transcriptome analysis of eyed-side muscle and blind-side muscle in Cynoglossussemilaevis (Osteichthyes, Cynoglossidae)

Cynoglossussemilaevis (Osteichthyes, Cynoglossidae) is one of the most significant commercial marine fish species in China and has evolved a specialized asymmetrical body axis. In addition, C.semilaevis displays different muscle thickness between the eyed side and the blind side. However, the mechanisms underlying the muscle development difference between the two sides in C.semilaevis are unclear. In this study, we generated the first comparative investigation on the structure of muscle cells, and transcriptome analysis between the eyed-side muscle (ESM) and blind-side muscle (BSM) in C.semilaevis. Histological assays showed the obvious mosaic appearance of muscles on both the eyed side and blind side. However, the number of new muscle cells in ESM was significantly more than that in the BSM group. Comparative analyses of RNA-seq data showed that 1177 differentially expressed genes (DEGs) were identified between ESM and BSM groups, including 291 up-regulated and 886 down-regulated genes. The expression levels of myosin family genes (actin, myosin-binding protein C, titin, troponin, tnnil, and astrotactin-2) were significantly higher in ESM and might be a candidate regulator of muscle filament assembly in C.semilaevis. Murine double minute 2 (Mdm2) and cyclin A2 (ccna2) were also up-regulated in ESM, which indicates that the muscle development difference between ESM and BSM in C.semilaevis might be owing to the variation in myofibroblast proliferation. In addition, KEGG pathway enrichment analyses suggested that the glycolysis/gluconeogenesis pathway may be involved in the muscle development of C.semilaevis. Taken together, this study may provide useful information to understand the molecular mechanism of muscle development in flatfishes.

Transcriptome analysis identifies potential molecular mechanisms for growth of fast muscle in Chinese perch juvenile

Chinese perch (Siniperca chuatsi) is an important commercial fish species in China. Understanding the molecular mechanisms of growth and development of skeletal muscle is helpful for selection breeding and improving the growth rate of Chinese perch. We analyzed histological and transcriptomic differences in fast muscle of Chinese perch between 30 days post hatching (dph) and 60 dph using histological sections and high-throughput RNA-Seq. The results showed that the diameter of muscle fibers in 30 dph Chinese perch was mainly distributed in range of 30 - 40 μm, and that of 60 dph was primarily in the range of 40 - 50 μm. 34 differentially expressed genes (DEGs) were identified in the fast muscle of Chinese perch between 30 and 60 dph, of which 9 were up-regulated and 25 were down-regulated (60 dph vs 30 dph). The DEGs, including MYH4, ENO3, Bag3, krt13 and krt18, are associated with muscle cell differentiation and fusion in Chinese perch. The analysis of the protein-protein interaction network of DEGs revealed that FOS, junb and EGR1 may involve in the development of fast muscle. KEGG enrichment results showed that the up-regulated genes in the 60 dph were associated with several pathways related to metabolism and protein synthesis, such as glycosphingolipid biosynthesis and aminoacyl-tRNA biosynthesis. The results suggest that the development of fast muscle in Chinese perch from 30 to 60 dph is accompanied by an increase in muscle fiber diameter and changes in gene expression related to muscle cell differentiation and protein synthesis. Abbreviations: DEGs, differentially expressed genes; dph, days post hatching; FC, fold change; FDR, False Discovery Rate; GO, Gene Ontology; KEGG, Kyoto Encyclopedia of Genes and Genomes; MyHCs, Myosin heavy chains; qRT-PCR, quantitative real-time PCR.

The Impact of Acute Ammonia Nitrogen Stress on the Gill Tissue Structure and Antioxidant Ability of Gills and Red and White Muscle in Juvenile Yellowfin Tuna (Thunnus albacares)

To explore the impacts of acute ammonia nitrogen (NH3-N) stress on gill structure and the antioxidant ability of red and white muscles in juvenile yellowfin tuna (Thunnus albacares), this study used natural seawater as a control, establishing two experimental NH3-N groups at 5 and 10 mg/L. Gills and red and white muscle were taken at 6, 24, and 36 h for the determination of malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GHS-PX) levels, and to observe gill structure. The results indicated that, with increasing time, the MDA concentration and CAT activity in the gills of the 5 mg/L group showed a trend of first increasing and then decreasing, while SOD activity exhibited a downward trend. In the 10 mg/L group, MDA concentration showed an increasing trend, while SOD, CAT, and GSH-PX activities demonstrated a trend of first increasing and then decreasing. In the 5 mg/L group, the MDA concentration and GSH-PX activity in the red muscle showed an increasing trend. In the 10 mg/L group, MDA concentration and SOD and CAT activities exhibited a downward trend. In the 5 mg/L group, the MDA concentration and SOD activity in the white muscle showed a downward trend, while CAT activity exhibited an increasing trend. In the 10 mg/L group, MDA concentration and CAT activity demonstrated a trend of first increasing and then decreasing, while SOD activity showed a downward trend. Ammonia nitrogen can lead to necrosis and shedding of gill epithelial cells, cell vacuolation, edema, as well as proliferation, hypertrophy, and fusion of secondary lamellae. This study demonstrates that NH3-N can alter gill structure and reduce the antioxidant ability of gills and red-white muscle. The findings provide scientific data that can support the aquaculture and recirculating aquaculture systems of juvenile tuna.

Enhancing bighead carp cutting: Chilled storage insights and machine vision-based segmentation algorithm development

To enhance market demand and fish utilization, cutting processing is essential for fish. Bighead carp were cut into four primary cuts: head, dorsal, belly, and tail, collectively accounting for 77.03% of the fish's total weight. These cuts were refrigerated at 4 °C for 10 days, during which the muscle from each cut was analyzed. Pseudomonas.fragi proliferated most rapidly and was most abundant in eye muscle (EM), while Aeromonas.sobria showed similar growth patterns in tail muscle (TM). Notably, EM exhibited the highest rate of fat oxidation. TM experienced the most rapid protein degradation. Furthermore, to facilitate the cutting applied in mechanical processing, a machine vision-based algorithm was developed. This algorithm utilized color threshold and morphological parameters to segment image background and divide bighead carp region. Consequently, each cut of bighead carp had a different storage quality and the machine vision-based algorithm proved effective for processing bighead carp.

The Regulatory Role of Myomaker in the Muscle Growth of the Chinese Perch (Siniperca chuatsi)

The fusion of myoblasts is a crucial stage in the growth and development of skeletal muscle. Myomaker is an important myoblast fusion factor that plays a crucial role in regulating myoblast fusion. However, the function of Myomaker in economic fish during posthatching has been poorly studied. In this study, we found that the expression of Myomaker in the fast muscle of Chinese perch (Siniperca chuatsi) was higher than that in other tissues. To determine the function of Myomaker in fast muscle, Myomaker-siRNA was used to knockdown Myomaker in Chinese perch and the effect on muscle growth was determined. The results showed that the growth of Chinese perch was significantly decreased in the Myomaker-siRNA group. Furthermore, both the diameter of muscle fibers and the number of nuclei in single muscle fibers were significantly reduced in the Myomaker-siRNA group, whereas there was no significant difference in the number of BrdU-positive cells (proliferating cells) between the control and the Myomaker-siRNA groups. Together, these findings indicate that Myomaker may regulate growth of fast muscle in Chinese perch juveniles by promoting myoblast fusion rather than proliferation.

Research Progress on the Regulating Factors of Muscle Fiber Heterogeneity in Livestock: A Review

The type of muscle fiber plays a crucial role in the growth, development, and dynamic plasticity of animals' skeletal muscle. Additionally, it is a primary determinant of the quality of both fresh and processed meat. Therefore, understanding the regulatory factors that contribute to muscle fibers' heterogeneity is of paramount importance. Recent advances in sequencing and omics technologies have enabled comprehensive cross-verification of research on the factors affecting the types of muscle fiber across multiple levels, including the genome, transcriptome, proteome, and metabolome. These advancements have facilitated deeper exploration into the related biological questions. This review focused on the impact of individual characteristics, feeding patterns, and genetic regulation on the proportion and interconversion of different muscle fibers. The findings indicated that individual characteristics and feeding patterns significantly influence the type of muscle fiber, which can effectively enhance the type and distribution of muscle fibers in livestock. Furthermore, non-coding RNA, genes and signaling pathways between complicated regulatory mechanisms and interactions have a certain degree of impact on muscle fibers' heterogeneity. This, in turn, changes muscle fiber profile in living animals through genetic selection or environmental factors, and has the potential to modulate the quality of fresh meat. Collectively, we briefly reviewed the structure of skeletal muscle tissue and then attempted to review the inevitable connection between the quality of fresh meat and the type of muscle fiber, with particular attention to potential events involved in regulating muscle fibers' heterogeneity.

Effects of Substituting Tenebrio molitor and Elodea nuttallii as Feed on Growth, Flesh Quality and Intestinal Microbiota of Red Swamp Crayfish (Procambarus clarkii)

This study aimed to evaluate the impact of substituting a portion of feed with Tenebrio molitor (TM) and Elodea nuttallii (EN) on crayfish culture. A total of 270 crayfish (5.1 ± 0.4 g) were fed three different diet combinations (A: 100% feed; B: 80% feed + 10% TM + 10% EN; C: 75% feed + 15% TM + 10% EN) for 12 weeks. The findings demonstrated that group C had an important beneficial impact on the growth performance of crayfish. This was evidenced by a rise in digestive enzyme activity (trypsin, lipase, and cellulase) in the intestinal and hepatopancreas, as well as an upregulation in the expression of growth-related genes (ghsr, igfbp7, mhc, mlc1, mef2, and pax7) in the muscle. Furthermore, the assessment of the flesh quality of crayfish muscle in group C was conducted. The findings indicated a significant increase (p < 0.05) in the energy value (moisture, crude protein, and crude lipid) within the muscle. The levels of delicious amino acids (Glu, Ala, Ser, Gly, and Tyr) and polyunsaturated fatty acids (ARA, DHA) were enhanced, resulting in an improved nutritional profile and flavor of the muscle while maintaining the Σn-3/Σn-6 ratio. The remodeling of the intestinal microbiota (abundance of Proteobacteria and ratio of Firmicutes/Bacteroidota bacteria) also revealed improved growth performance. Additional research is necessary to ascertain whether excessive use of TM or EN feed substitution can have negative effects on crayfish culture.