TRIENNIAL GROWTH SYMPOSIUM: THE NUTRITION OF MUSCLE GROWTH: Impacts of nutrition on the proliferation and differentiation of satellite cells in livestock species1,2

Inhibitor of Myom3 inhibits proliferation and promotes differentiation of sheep myoblasts

Skeletal muscle quality and yield are important production traits in livestock, and improving skeletal muscle quality while increasing its yield is an important goal of economic breeding. The proliferation and differentiation process of sheep myoblasts directly affects the growth and development of their muscles, thereby affecting the yield of mutton. Myomesin 3 (Myom3), as a functional gene related to muscle growth, currently lacks research on its function in myoblasts. This study aims to investigate the effect of the Myom3 gene on the proliferation and differentiation of sheep myoblasts and its potential molecular mechanisms. The results showed that inhibitor of Myom3 in the proliferation phase of myoblasts resulted in significant downregulation of the proliferation marker gene paired box 7 (Pax7) and myogenic regulatory factors (MRFs; Myf5, Myod1, Myog, P < 0.01), a significant decrease in the EdU-positive cell rate (P < 0.05), and a significant increase in the cell apoptosis rate (P < 0.01), which inhibited the proliferation of myoblasts and promoted their apoptosis. During the differentiation phase of myoblasts, the inhibitor of Myom3 resulted in significant downregulation of the Pax7 gene, upregulation of MRFs (Myod1, Myog, P < 0.05), and a significant increase in fusion index (P < 0.05), promoting the differentiation of myoblasts. Further transcriptome sequencing revealed that differentially expressed genes in the Myom3 interference group were mainly enriched in the MAPK signaling pathway, TNF signaling pathway, and IL-17 signaling pathway. In summary, the inhibitor of Myom3 inhibits myoblast proliferation and promotes myoblast differentiation. Therefore, Myom3 has a potential regulatory effect on the growth and development of sheep muscles, and in-depth functional research can be used for molecular breeding practices in sheep.

Transcriptome analysis of mRNA and miRNA in the development of LeiZhou goat muscles

The progression of muscle development is a pivotal aspect of animal ontogenesis, where miRNA and mRNA exert substantial influence as prominent players. It is important to understand the molecular mechanisms involved in skeletal muscle development to enhance the quality and yield of meat produced by Leizhou goats. We employed RNA sequencing (RNA-SEQ) technology to generate miRNA-mRNA profiles in Leizhou goats, capturing their developmental progression at 0, 3, and 6 months of age. A total of 977 mRNAs and 174 miRNAs were found to be differentially expressed based on our analysis. Metabolic pathways, calcium signaling pathways, and amino acid synthesis and metabolism were found to be significantly enriched among the differentially expressed mRNA in the enrichment analysis. Meanwhile, we found that among these differentially expressed mRNA, some may be related to muscle development, such as MYL10, RYR3, and CSRP3. Additionally,, we identified five muscle-specific miRNAs (miR-127-3p, miR-133a-3p, miR-193b-3p, miR-365-3p, and miR-381) that consistently exhibited high expression levels across all three stages. These miRNAs work with their target genes (FHL3, SESN1, PACSIN3, LMCD1) to regulate muscle development. Taken together, our findings suggest that several miRNAs and mRNAs are involved in regulating muscle development and cell growth in goats. By uncovering the molecular mechanisms involved in muscle growth and development, these findings contribute valuable knowledge that can inform breeding strategies aimed at enhancing meat yield and quality in Leizhou goats.

Identification of key differentially methylated genes in regulating muscle development and intramuscular fat deposition in chickens

Muscle development and intramuscular fat (IMF) deposition are intricate physiological processes characterized by multiple gene expressions and interactions. In this research, the phenotypic variations in the breast muscle of Jingyuan chickens were examined at three different time points: 42, 126, and 180 days old. Differential expression analysis and weighted gene co-expression network analysis (WGCNA) were performed to identify differentially methylated genes (DMGs) responsible for regulating muscle development and IMF deposition. The findings indicate a significant increase in breast muscle weight (BMW), myofiber diameter, and cross-sectional area, as well as IMF content, in correlation with the progressive number of growing days in Jingyuan chickens. The findings also revealed that 380 hypo-methylated and 253 hyper-methylated DMGs were identified between the three groups of breast muscle. Module gene and DMG association analysis identified m6A methylation-mediated multiple DMGs associated with muscle development and fat metabolism. In vitro cell modeling analysis reveals stage-specific differences in the expression of CUBN, MEGF10, BOP1, and BMPR2 during the differentiation of myoblasts and intramuscular preadipocytes. Cycloleucine treatment significantly inhibited the expression levels of CUBN, BOP1, and BMPR2, and promoted the expression of MEGF10. These results suggest that m6A methylation-mediated CUBN, MEGF10, BOP1, and BMPR2 can serve as potential candidate genes for regulating muscle development and IMF deposition, and provide an important theoretical basis for further investigation of the functional mechanism of m6A modification involved in adipogenesis.

Loss of MuRF1 in Duroc pigs promotes skeletal muscle hypertrophy

Muscle mass development depends on increased protein synthesis and reduced muscle protein degradation. Muscle ring-finger protein-1 (MuRF1) plays a key role in controlling muscle atrophy. Its E3 ubiquitin ligase activity recognizes and degrades skeletal muscle proteins through the ubiquitin-proteasome system. The loss of Murf1, which encodes MuRF1, in mice leads to the accumulation of skeletal muscle proteins and alleviation of muscle atrophy. However, the function of Murf1 in agricultural animals remains unclear. Herein, we bred F1 generation Murf1^+/- and F2 generation Murf1^-/- Duroc pigs from F0 Murf1^-/- pigs to investigate the effect of Murf1 knockout on skeletal muscle development. We found that the Murf1^+/- pigs retained normal levels of muscle growth and reproduction, and their percentage of lean meat increased by 6% compared to that of the wild type (WT) pigs. Furthermore, the meat color, pH, water-holding capacity, and tenderness of the Murf1^+/- pigs were similar to those of the WT pigs. The drip loss rate and intramuscular fat decreased slightly in the Murf1^+/- pigs. However, the cross-sectional area of the myofibers in the longissimus dorsi increased in the adult Murf1^+/- pigs. The skeletal muscle proteins MYBPC3 and actin, which are targeted by MuRF1, accumulated in the Murf1^+/- and Murf1^-/- pigs. Our findings show that inhibiting muscle protein degradation in MuRF1-deficient Duroc pigs increases the size of their myofibers and their percentage of lean meat without influencing their growth or pork quality. Our study demonstrates that Murf1 is a target gene for promoting skeletal muscle hypertrophy in pig breeding.

Semi-automated technique for bovine skeletal muscle fiber cross-sectional area and myosin heavy chain determination

Myosin heavy chain (MyHC) type and muscle fiber size are informative but time-consuming variables of interest for livestock growth, muscle biology, and meat science. The objective of this study was to validate a semi-automated protocol for determining MyHC type and size of muscle fibers. Muscle fibers obtained from the longissimus and semitendinosus of fed beef carcasses were embedded and frozen within 45 min of harvest. Immunohistochemistry was used to distinguish MyHC type I, IIA, and IIX proteins, dystrophin, and nuclei in transverse sections of frozen muscle samples. Stained muscle cross sections were imaged and analyzed using two workflows: 1) Nikon workflow which used Nikon Eclipse inverted microscope and NIS Elements software and 2) Cytation5 workflow consisting of Agilent BioTek Cytation5 imaging reader and Gen5 software. With the Cytation5 workflow, approximately six times more muscle fibers were evaluated compared to the Nikon workflow within both the longissimus (P < 0.01; 768 vs. 129 fibers evaluated) and semitendinosus (P < 0.01; 593 vs. 96 fibers evaluated). Combined imaging and analysis took approximately 1 h per sample with the Nikon workflow and 10 min with the Cytation5 workflow. When muscle fibers were evaluated by the objective thresholds of the Cytation5 workflow, a greater proportion of fibers were classified as glycolytic MyHC types, regardless of muscle (P < 0.01). Overall mean myofiber cross-sectional area was 14% smaller (P < 0.01; 3,248 vs. 3,780) when determined by Cytation5 workflow than when determined by Nikon workflow. Regardless, Pearson correlation of mean muscle fiber cross-sectional areas determined by Nikon and Cytation5 workflows was 0.73 (P < 0.01). In both workflows cross-sectional area of MyHC type I fibers was the smallest and area of MyHC type IIX fibers was the largest. These results validated the Cytation5 workflow as an efficient and biologically relevant tool to expedite data capture of muscle fiber characteristics while using objective thresholds for muscle fiber classification.

The Effects of Prenatal Diet on Calf Performance and Perspectives for Fetal Programming Studies: A Meta-Analytical Investigation

This meta-analysis aimed to identify knowledge gaps in the scientific literature on future fetal-programming studies and to investigate the factors that determine the performance of beef cows and their offspring. A dataset composed of 35 publications was used. The prenatal diet, body weight (BW), average daily gain (ADG) during pregnancy, and calf sex were elicited as possible modulators of the beef cows and their offspring performance. Then, the correlations between these variables and the outcomes of interest were investigated. A mixed multiple linear regression procedure was used to evaluate the relationships between the responses and all the possible explanatory variables. A knowledge gap was observed in studies focused on zebu animals, with respect to the offspring sex and the consequences of prenatal nutrition in early pregnancy. The absence of studies considering the possible effects promoted by the interactions between the different stressors' sources during pregnancy was also detected. A regression analysis showed that prenatal diets with higher levels of protein improved the ADG of pregnant beef cows and that heavier cows give birth to heavier calves. Variations in the BW at weaning were related to the BW at birth and calf sex. Therefore, this research reinforces the importance of monitoring the prenatal nutrition of beef cows.

Weighted gene co-expression network indicates that the DYNLL2 is an important regulator of chicken breast muscle development and is regulated by miR-148a-3p

BACKGROUND

The characteristics of muscle fibers determine the growth and meat quality of poultry. In this study, we performed a weighted gene co-expression network analysis (WGCNA) on the muscle fiber characteristics and transcriptome profile of the breast muscle tissue of Gushi chicken at 6, 14, 22, and 30 weeks.

RESULTS

A total of 27 coexpressed biological functional modules were identified, of which the midnight blue module had the strongest correlation with muscle fiber and diameter. In addition, 7 hub genes were found from the midnight blue module, including LC8 dynein light chain 2 (DYNLL2). Combined with miRNA transcriptome data, miR-148a-3p was found to be a potential target miRNA of DYNLL2. Experiments on chicken primary myoblasts (CPMs) demonstrated that miR-148a-3p promotes the expression of myosin heavy chain (MYHC) protein by targeting DYNLL2, proving that it can promote differentiation of myoblasts.

CONCLUSIONS

This study proved that the hub gene DYNLL2 and its target miR-148-3p are important regulators in chicken myogenesis. These results provide novel insights for understanding the molecular regulation mechanisms related to the development of chicken breast muscle.

Whole-genome resequencing to investigate the determinants of the multi-lumbar vertebrae trait in sheep

Multi-lumbar vertebrae trait is a beneficial mutation that can significantly improve livestock meat production. However, the genetic basis of the multi-lumbar vertebrae in sheep is still unclear. Here, we analysed the number of lumbar vertebrae of Duolang sheep and found three different traits of lumbar vertebrae number. Compared with the normal sheep, the length and weight of animal carcass from the multi-lumbar vertebrae sheep increased by 2.21 cm and 0.78 kg, respectively. We performed high-throughput genome resequencing on multi-lumbar vertebrae (n = 18) and normal (n = 11) Duolang sheep and obtained a total of more than 528.87 GB data. We found that the most significantly selective region were located in the 49.68-49.74 MB of chromosome 4 by selective-sweep analysis. We annotated this region and found that it contains SFRP4 which is known to regulate bone development. We further used the PCR-SSCP technology to detect the single nucleotide polymorphism (SNP) of the putative candidate SFRP4 and found that the two SNPs (rs600370085:C > T and rs415133338: A > G) of this gene were significantly associated with the multi-lumbar vertebrae of Duolang sheep. Our study indicates that the SFRP4 may be a potential major gene that affects the number of lumbar vertebrae in Duolang sheep, and has the potential to be utilized for sheep breeding in the future.

Nutritional Influences on Skeletal Muscle and Muscular Disease

Skeletal muscle comprises 40% to 55% of mature body weight in horses, and its mass is determined largely by rates of muscle protein synthesis. In order to support exercise, appropriate energy sources are essential: glucose can support both anaerobic and aerobic exercise, whereas fat can only be metabolized aerobically. Following exercise, ingestion of nonfiber carbohydrates and protein can aid muscle growth and recovery. Muscle glycogen replenishment is slow in horses, regardless of dietary interventions. Several heritable muscle disorders, including type 1 and 2 polysaccharide storage myopathy and recurrent exertional rhabdomyolysis, can be managed in part by restricting dietary nonstructural carbohydrate intake.

Ante-Natal and Post-Natal Influences on Neonatal Immunity, Growth and Puberty of Calves-A Review

Simple Summary

The objective of this review is to give the reader an overview of interactions between immunity, growth and puberty in calves and highlight how these influence future performances. The risk of morbidity and mortality is high during the first four weeks of age. Adaption to extra-uterine life starts early during embryonic development and is underpinned by optimal maternal nutrition. It is known that colostrum is paramount to neonate nutrition and passive immunity. Good colostrum management allows the calf to develop coping mechanisms to efficiently utilize feed resources for optimal growth. A deeper understanding of these interactions paves the way for developing strategies to improve immune responses to environmental pathogens, optimal growth and timely attainment of puberty in calves. The literature reviewed here shows that there are opportunities to enhance future performance of cattle paying attention to the interaction of nutrition and immunity at early developmental stages. This then guarantees efficient neonate nutrition and profitable cattle production.

Abstract

Calf immunity, growth and puberty are important factors affecting heifer productivity. The first four weeks of age are critical for reducing calf morbidity and mortality. It is well documented that colostrum is paramount to neonatal nutrition and passive immunity, however, adaptation to extra-uterine life starts early during embryonic development. Therefore, successful calf rearing strategies are underpinned by adequate maternal nutrition during gestation, and good colostrum management. A deeper understanding of these interactions paves the way for developing strategies to improve immune responses to environmental pathogens, optimal growth and timely attainment of puberty in calves. The literature reviewed here shows that there are opportunities to enhance the future performance of cattle paying attention to the interaction of nutrition and immunity at each developmental stage. Therefore, the objective of this review is to give the reader an overview of interactions between immunity, growth and puberty in dairy calves and highlight how these influence future performances.

The Impact of Polyamine Precursors, Polyamines, and Steroid Hormones on Temporal Messenger RNA Abundance in Bovine Satellite Cells Induced to Differentiate

Simple Summary

In the U.S., approximately 90% of all cattle on feed receive an anabolic implant at some point during production. Despite the widespread use, how they operate to increase growth of cattle remains unknown. Polyamines are amino acid derivatives, which are potent growth stimulants, produced through the polyamine biosynthetic pathway. Emerging research suggests that the hormones in anabolic implants interact with the polyamine biosynthetic pathway. The purpose of this research was to investigate the effects of steroidal hormones, polyamine precursors, and polyamines on mRNA abundance of bovine satellite cells, muscle precursor cells. The results from this study suggest that polyamine precursors and polyamines alter transcription factors involved in induction of differentiation of bovine satellite cells and the polyamine biosynthetic pathway, while the hormones in anabolic implants alter genes involved in the polyamine biosynthetic pathway. These results mean that polyamines may impact differentiation of bovine satellite cells, ultimately affecting growth of cattle.

Abstract

Emerging research suggests that hormones found in anabolic implants interact with polyamine biosynthesis. The objective of this study was to determine the effects of steroidal hormones, polyamines and polyamine precursors on bovine satellite cell (BSC) differentiation and polyamine biosynthesis temporally. Primary BSCs were induced to differentiate in 3% horse serum (CON) and treated with 10 nM trenbolone acetate (TBA), 10 nM estradiol (E2), 10 nM TBA and 10 nM E2, 10 mM methionine, 8 mM ornithine, 2 mM putrescine, 1.5 mM spermidine, or 0.5 mM spermine. Total mRNA was isolated 0, 2, 4, 8, 12, 24, and 48 h post-treatment. Abundance of mRNA for genes associated with induction of BSC differentiation: paired box transcription factor 7, myogenic factor 5, and myogenic differentiation factor 1 and genes in the polyamine biosynthesis pathway: ornithine decarboxylase and S-adenosylmethionine—were analyzed. Overall, steroidal hormones did not impact (p > 0.05) mRNA abundance of genes involved in BSC differentiation, but did alter (p = 0.04) abundance of genes involved in polyamine biosynthesis. Polyamine precursors influenced (p < 0.05) mRNA of genes involved in BSC differentiation. These results indicate that polyamine precursors and polyamines impact BSC differentiation and abundance of mRNA involved in polyamine biosynthesis, while steroidal hormones altered the mRNA involved in polyamine biosynthesis.

Growth Performance, Serum Biochemical Indices, Duodenal Histomorphology, and Cecal Microbiota of Broiler Chickens Fed on Diets Supplemented with Cinnamon Bark Powder at Prestarter and Starter Phases

Ross 308 broiler chicks (n = 240) aged 1 day were assigned to five groups for eight replicates (six chicks for each) (3♂ and 3♀). Basal dietary groups were supplemented by 2000, 4000, and 6000 mg/kg cinnamon (CN) for 21 days. Basal diet alone was used as a negative control, and basal antibiotic diet (Colimox) was used as a positive control. At 10, 14, and 21 days of age, chicks that received 2000 mg CN and Colimox had a higher body weight, resulting in an increase in body weight gain. CN also resulted in the maximum improvement in the feed conversion ratio and feed efficiency over 1-21 days at the level of 2000 mg/kg. At days 10, the maximum relative breast weight was 2000 mg/kg of CN. Mean serum albumin concentrations, duodenal villus height, and goblet cell density increased (p < 0.05) by 2000 mg/kg of CN, and mean serum globulin and total protein concentrations and crypt depth increased (p < 0.05) by 6000 mg/kg of CN compared with control. Increased cecal Escherichia coli number was CN dose-dependent. In conclusion, dietary inclusion of 2000 mg/kg CN can be applied as an alternative to in-feed antibiotics for broiler starter diet.

Characterisation of intracellular molecular mechanisms modulated by carnosine in porcine myoblasts under basal and oxidative stress conditions

Carnosine is a naturally occurring histidine-containing dipeptide present at high concentration in mammalian skeletal muscles. Carnosine was shown to affect muscle contraction, prevent the accumulation of oxidative metabolism by-products and act as an intracellular proton buffer maintaining the muscle acid-base balance. The present study was undertaken to gain additional knowledge about the intracellular mechanisms activated by carnosine in porcine myoblast cells under basal and oxidative stress conditions. Satellite cells were isolated from the skeletal muscles of 3 to 4 day-old piglets to study the effect of 0, 10, 25 and 50 mM carnosine pre-treatments in cells that were exposed (0.3 mM H2O2) or not to an H2O2-induced oxidative stress. Study results demonstrated that carnosine acts differently in myoblasts under oxidative stress and in basal conditions, the only exception being with the reduction of reactive oxygen species and protein carbonyls observed in both experimental conditions with carnosine pre-treatment. In oxidative stress conditions, carnosine pre-treatment increased the mRNA abundance of the nuclear factor, erythroid 2 like 2 (NEF2L2) transcription factor and several of its downstream genes known to reduce H2O2. Carnosine prevented the H2O2-mediated activation of p38 MAPK in oxidative stress conditions, whereas it triggered the activation of mTOR under basal conditions. Current results support the protective effect of carnosine against oxidative damage in porcine myoblast cells, an effect that would be mediated through the p38 MAPK intracellular signaling pathway. The activation of the mTOR signaling pathway under basal condition also suggest a role for carnosine in myoblasts proliferation, growth and survival.