Chicken Breast Muscle Research Articles

BODY WEIGHT, MUSCLE WIGHT, PROTEIN, DNA AND RNA CONTENTS IN BREAST MUSCLE (M. Pectoralis Major) OF SELECTED LOCAL MEAT CHICKEN FED ON A DIFFERENT LEVEL OF KIAPU (Pistia stratiotes L.) IN FERMENTED DIET

The study to evaluate changes in body weight, muscle weight, muscle protein content and total DNA and RNA on breast muscle of selectedlocal chicken due to different levels of fermented feed containing Kiapu (Pistia stratiotes L.) was conducted using a factorial randomized designfor 7 weeks. This study used 72 selected local chickens, which were separated into 2 groups (male and female) and fed on 3 types of feedtreatment, namely P0 (control treatment with 100% commercial feed), P1 (80% commercial feed + 20% fermented Kiapu feed), and P2 (70%commercial feed + 30% fermented Kiapu feed). Parameters were body weight, muscle weight, muscle protein content and total DNA and RNAon breast muscle of chicken. Total protein, DNA and RNA content were analysed by enzymatic reactions of prokaryotic cell and measured with aUV-Spectrophotometer according to the specified OD (optical density). The results showed that feeding Kiapu fermented 20-30% increased bodyweight and protein content of breast muscle of female chicken by change in DNA content. However, the feeding treatment had no changes inmuscle weight and RNA content of both in male and female chicken. On the other hand, substitution of 20-30% Kiapu fermented feed causednegative changes in DNA level of breast muscle. From this study, it was concluded that substitution of fermented feed containing 20-30% Kiapuassociated with the growth process of breast muscle protein is suitable for female but not suitable for male chicken.

Identification of suitable reference genes for normalization of quantitative real-time PCR-based gene expression in chicken (Gallus gallus).

The recent availability of genome information greatly facilitates the fundamental research on chicken. In different organs, gene expression patterns can provide clues to understanding the biological functions. For rapid and accurate quantification of gene expression, quantitative real-time PCR (qPCR) has become one of the most widely used methods. However, the success of qPCR data normalization depends on the use of a suitable reference gene and a single reference gene is not universally suitable for all the experiments. Therefore, reference gene validation is a crucial step for different organ tissues of chicken where suitable reference genes for qPCR analysis in varieties of tissues have not been investigated exhaustively so far. In this study, we have selected 30 Gallus gallus candidate reference genes from NCBI, amplified and studied their expression profiles by qPCR in different organ tissues (breast muscle, thigh muscle, heart, liver, spleen, gizzard, and bursa) of chicken. The result showed that, for breast muscle HSP10 and RPL23, thigh muscle RPL14 and RPL13, liver ALB and HSP70, spleen ALB and GAPDH, heart CYCS and TUBA8B, gizzard RPL5 and 18S rRNA, and bursa EEF1A1 and PGK2 are most stable genes respectively. The results also showed that for different organ tissues, individual or a combination of reference genes should be selected for data normalization. In this study, we have identified and validated 30 reference genes in seven different organ tissues to provide accurate transcript normalization and quantification, which can be useful for gene expression studies in other avian species.

Changes in lipids metabolism indices as a result of different form of selenium supplementation in chickens

Selenium is an essential element that is important for many metabolic processes. Feed components used in chicken nutrition, especially cereals, may be deficient in selenium, hence selenium supplementation is necessary. Taking into account the progress in breeding, and thus the higher demand of birds for this element, it seems obvious to investigate an increased selenium dose in the diet of chickens. The aim of the study was to evaluate the effect of feed enriched with different forms of selenium at an increased dose of 0.5 mg/kg feed on the profile and metabolism of fatty acids in the breast muscle and liver of chickens. The study was conducted on 300 Ross 308 chickens reared for 42 days under standard conditions. The control group received feed supplemented with sodium selenite at a dose of 0.3 mg/kg feed. The research groups received different forms of selenium (sodium selenate, selenised yeast, nano-selenium) at an increased dose of 0.5 mg/kg feed. The study showed that the administration of different forms of selenium in the feed affected its concentration in the breast muscle and liver (p ≤ 0.01). Nano-selenium was found to have a high bioavailability, but also a lower risk of toxicity compared to other forms of selenium. Using different forms of selenium (p ≤ 0.01) at a dose of 0.5 mg/kg feed can significantly modify the fatty acid profile, lipid and enzymatic indices of fatty acid metabolism in breast muscle and liver.

Mitochondrial characteristics of chicken breast muscle affected by wooden breast

The growth rate of broiler chickens has increased by 400% over the past 50 years, and breast yields continue to increase. This has led to an increase in thoracic muscle abnormalities in broilers, with wooden breast becoming a major issue worldwide. The etiology and the mechanism underlying the etiology of wooden breasts have not yet been elucidated; however, it occurs due to oxidative stress. Reactive oxygen species, which cause oxidative stress, are mainly produced in mitochondria. Thus, in this study, we investigated the relationship between the severity of wooden breast in broilers and the characteristics of mitochondria as the source of reactive oxygen species. Sampling of the pectoralis major muscle at the ventral cranial position was conducted in 50-day-old broilers. The severity of wooden breast was classified into three groups based on the muscle fiber roundness and wing–wing contact test, with highest severity in severe wooden breast and lowest severity in normal breast. Nicotinamide adenine dinucleotide tetrazolium reductase staining revealed an increase in darkly stained muscle fibers, indicating high severity of wooden breast. The mitochondria were swollen in severe wooden breast cases, with highest swelling in severe wooden breast and lowest swelling in normal breast. The expression levels of the mitochondrial antioxidant enzyme genes superoxide dismutase 1 and superoxide dismutase 2 were significantly lower in wooden breast-severe tissue than in normal tissue. These results suggest that when the levels of reactive oxygen species in muscle fibers, which should be constant, are increased, mitochondrial homeostasis is not maintained and the damage levels increase in various membranes of the cell, leading to the disruption of normal physiological functions.

Intermittent dilution of dietary digestible lysine lowers the incidence of white striping by suppressing the growth, lipid synthesis, and muscle damage in broiler chickens.

White striping (WS) is a myopathy of breast muscle (Pectoralis major) that affects the quality and consumer acceptance of breast fillets of broiler chickens. Previous studies have shown that intermittent dilution of dietary nutrients suppresses the development of WS on the breast muscle of broiler chickens. However, the mechanism by which these interventions reduce the occurrence of WS remains inconclusive. In this study, we adopted intermittent reduction of dietary digestible lysine (dLys) density or metabolizable energy (ME) and amino acid (AA) density using chemical and fatty acid composition of breast fillets, and blood metabolites to understand the mechanism while histopathology and immunohistochemistry of breast muscles were used for confirmation. Occurrence of WS was lower in broiler chickens fed 85% dLys diets in comparison with other groups. Crude protein and ether extract in breast meat of 85% dLys groups were greater (P < 0.001) and lower (P=0.010), respectively. Serum concentrations of lipid metabolites and enzymes were lower in broiler chickens fed 85% dLys diets than control group (P < 0.05). Feeding 85% dLys diets had low degree of myodegeneration and necrosis, inflammation, lipid deposition, infiltration of T-lymphocyte (CD3+) and macrophages (Iba-1+), and low expression of heat-shock protein 70 (HSP70) than other groups (P < 0.001). Dilution of dietary dLys to 85% of the required quantities reduces the development of WS in broiler chickens by slowing the growth, lipid synthesis, and muscle damage confirmed by lower extent of histopathological lesions. © 2022 Society of Chemical Industry.

Optical Property Measurement and Temperature Monitoring in High-Intensity Focused Ultrasound Therapy by Diffuse Optical Tomography: A Correlation Study

In this article, we propose a new approach utilizing diffuse optical tomography (DOT) to monitoring the changes in tissues’ optical properties and temperature in high-intensity focused ultrasound (HIFU) therapy. By correlating the tissue reduced scattering coefficient (μs’) reconstructed by DOT and the temperature measured by a thermocouple, the quantitative relationship between μs’ and temperature in HIFU treatment was explored. The experiments were conducted using porcine and chicken breast muscle tissues during HIFU; the temperature of each tissue sample was recorded using a thermocouple. To incorporate the temperature dependency of tissue optical properties, both polynomial and exponential models were utilized to fit the experimental data. The results show that the change of μs’ during HIFU treatment could be detected in real-time using DOT and that this change of μs’ is quantitatively correlated with tissue temperature. Furthermore, while the tissue-type-dependent relationship between μs’ and temperature is non-linear in nature, it is stable and repeatable. Therefore, our approach has the potential to be used to predict temperature of tissue during HIFU treatment.

A Comparison of Different Tissues Identifies the Main Precursors of Volatile Substances in Chicken Meat.

Amino acids and fatty acids are the main precursors of volatile organic compounds (VOCs) in meat. The purpose of this study was to determine the main VOC components in chicken breast muscle (BM) and abdominal fat (AF) tissue, as well as the source of VOCs, to provide a basis for quality improvement of broilers. BM and AF served as experimental and control groups, and gas chromatography-mass spectrometry (GC-MS) and untargeted metabolomics were employed to identify the source of VOCs. The results revealed nine VOCs in BM and AF tissues, including hexanal, octanal, and nonanal. VOCs including 1-octen-3-ol, (E,E)-2, 4-nonadienal, and benzaldehyde were significantly elevated in BM compared with AF (p < 0.05), while heptane and diethyl disulphide showed the opposite trend (p < 0.05). Levels of hexanal, heptanal, and octanal were similar in the two tissues. Metabolites of VOCs in chicken BM were investigated by weighted co-expression network analysis. However, only blue module in BM tissue was positively correlated with hexanal (r = 0.66, p = 0.01), heptanal (r = 0.67, p = 0.008), and (E,E)-2,4-nonadienal (r = 0.88, p = 3E-05). L-tyrosine, L-asparagine, adenosine, and valine were the main precursors of (E,E)-2,4-nonadienal and heptanal in BM tissue. Amino acids are the main precursors of 1-octen-3-ol, (E,E)-2, 4-nonadienal, and heptanal in chicken meat, while fatty acids are the main precursors of diethyl disulfide. However, hexanal can be synthesized from amino acids and small amounts of fatty acids as precursors. These findings expand our understanding of VOCs in chicken.

NIR-II-absorbing conjugated polymers based on tetra-fused isoindigo ribbons for photothermal conversion and photoacoustic imaging

Conjugated polymers (CPs) that have both a high extinction coefficient (ε) and a high photothermal conversion efficiency (η) in the second near-infrared (NIR-II) region (1,000–1,700 nm) are highly desirable for photoacoustic imaging (PAI) and photothermal therapy (PTT). Here, we report that introducing polycyclic, auxochromic, and coplanar effects together into conjugated backbones affords isoindigo-based CPs with strong absorption and high η in the NIR-II region. Water-dispersed nanoparticles (NPs) of the typical polymer P4TTD-OT, with an ε in mass of 37.1 g −1 cm −1 and an η of 72.9% at 1,064 nm, show superior PAI properties. PAI of 40 mm depth at 1,064 nm is achieved at a lower laser fluence of 7.0 mJ cm −2 with chicken breast muscle as a model tissue, while a signal-to-background ratio of up to 42 dB is realized in the in vivo NIR-II PAI using the 4T1 tumor-bearing mouse model. The NPs can also serve as an effective NIR-II nanoagent for PAI-guided PTT. • A strategy for the synthesis of NIR-II-absorbing CPs is proposed • High η up to 72.9% at 1,064 nm is achieved • Tissue penetration depth of PAI signals up to 40 mm is achieved Jiang et al. report that the combination of polycyclic, auxochromic, and coplanar effects can afford conjugated polymers with high NIR-II molar extinction coefficient and photothermal conversion efficiency.

Breast Meat Fatty Acid Profiling and Proteomic Analysis of Beijing-You Chicken During the Laying Period.

The disparity in fatty acids (FA) composition exhibits a significant impact on meat quality, however, the molecular regulatory mechanisms underlying this trait in chicken are far from clear. In this study, a total of 45 female Beijing-You chicken (BYC) hens, fed on the same diet, were collected at the slaughter age of 150, 300, or 450 days (D150, D300, and D450) from sexual maturation stage to culling stage (15 birds per age). Gas chromatography-mass spectrometry (GC-MS) and tandem mass tag labeling technology based on liquid chromatography mass spectrometry (TMT-LC-MS/MS) analysis strategies were applied to profile FA compositions and to compare differential expressed proteins (DEPs) between these different slaughter ages, respectively. The FA profiling showed that increasing hen ages resulted in increased contents of both saturated and unsaturated fatty acids. Proteomic analyses showed a total of 4,935 proteins in chicken breast muscle with the false discovery rate (FDR) < 1% and 664 of them were differentially expressed (fold change > 1.50 or < 0.67 and P < 0.01). There were 410 up- and 116 down-regulated proteins in D150 vs. D300 group, 32 up- and 20 down-regulated in D150 vs. D450 group, and 72 up- and 241 down-regulated in D300 vs. D450 group. A total of 57 DEPs related to FA/lipid-related metabolisms were obtained according to the enrichment analysis of Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG). These DEPs were involved in 21 significantly enriched (P < 0.05) pathways, including well-known pathways for FA synthesis (metabolism, desaturation, and elongation) and the signaling pathways for lipid metabolism (PPAR, adipocytokine, calcium, VEGF, MAPK, and Wnt). In addition, there existed several representative DEPs (FABP, FABP3, apoA-I, apoA-IV, apoC-III, apoB, VTG1, and VTG2) involved in the regulation of FA/lipid transportation. The construction of the interaction networks indicated that HADH, ACAA2, HADHA, ACSL1, CD36, CPT1A, PPP3R1, and SPHK1 were the key core nodes. Finally, eight DEPs were quantified using parallel reaction monitoring (PRM) to validate the results from TMT analysis. These results expanded our understanding of how the laying age affects the FA compositions and metabolism in hen breast meat.

Effect of partial and complete substitution of lupin meal for soybean meal in diets on changes in fatty acid composition of muscle fat in broiler chickens

The experiment aimed to determine the effect of 50% (LS50) or 100% (LS100) substitution of lupin protein (variety Zulika) for soybean protein in feed mixtures intended for the nutrition of broiler chickens, on muscular fat quality (composition of fatty acids). There were established three groups of chickens for fattening with 80 individuals each (control group C and experimental groups). After the 34-day fattening period chicken breast and thigh muscles were analysed to find out the fatty acid composition. Lupin protein-based diets had a positive effect on the muscle quality of fattened chickens due to changes in fatty acid composition, compared to soya protein-based diets. The feeding of lupin-based diets to broiler chickens resulted in the reduction of saturated fatty acids (P ≤ 0.05) by 14% in LS50 group and 17% in LS100 group and increase of unsaturated fatty acids (P ≤ 0.05) by 58% in LS50 group and 90% in LS100 group in muscle fat. The results clearly confirm that lupin-based diet increases the dietary value of chicken meat as one of the most important protein sources in human nutrition.

Integrative analysis of circRNA, miRNA, and mRNA profiles to reveal ceRNA regulation in chicken muscle development from the embryonic to post-hatching periods

BackgroundThe growth and development of skeletal muscle are regulated by protein-coding genes and non-coding RNA. Circular RNA (circRNA) is a type of non-coding RNA involved in a variety of biological processes, especially in post-transcriptional regulation. To better understand the regulatory mechanism of circRNAs during the development of muscle in chicken, we performed RNA-seq with linear RNA depletion for chicken breast muscle in 12 (E 12) and17 (E 17) day embryos, and 1 (D 1), 14 (D 14), 56 (D 56), and 98 (D 98) days post-hatch.ResultsWe identified 5755 differentially expressed (DE)-circRNAs during muscle development. We profiled the expression of DE-circRNAs and mRNAs (identified in our previous study) at up to six time points during chicken muscle development and uncovered a significant profile (profile 16) for circRNA upregulation during aging in muscle tissues. To investigate competing endogenous RNA (ceRNA) regulation in muscle and identify muscle-related circRNAs, we constructed a circRNA-miRNA-mRNA regulatory network using the circRNAs and mRNAs from profile 16 and miRNAs identified in our previous study, which included 361 miRNAs, 68 circRNAs, 599 mRNAs, and 31,063 interacting pairs. Functional annotation showed that upregulated circRNAs might contribute to glycolysis/gluconeogenesis, biosynthesis of amino acids, pyruvate metabolism, carbon metabolism, glycogen and sucrose metabolism through the ceRNA network, and thus affected postnatal muscle development by regulating muscle protein deposition. Of them, circRNA225 and circRNA226 from the same host gene might be key circRNAs that could regulate muscle development by interacting with seven common miRNAs and 207 mRNAs. Our experiments also demonstrated that there were interactions among circRNA225, gga-miR-1306-5p, and heat shock protein alpha 8 (HSPA8).ConclusionsOur results suggest that adequate supply of nutrients such as energy and protein after hatching may be a key factor in ensuring chicken yield, and provide several candidate circRNAs for future studies concerning ceRNA regulation during chicken muscle development.

Studies to Explain Further, Why Percentages of Eicosanoid Precursor Fatty Acids Associate Positively in Chicken Muscle

Background: Polyunsaturated fatty acids with 20 or 22 carbon atoms are precursors of eicosanoids and docosanoids, which are important regulatory molecules in cell physiology. In breast muscle of chickens, we recently reported that percentages of these precursors were positively associated. Subsequently, we observed that the concentration ranges of the fatty acids seemed to cause the positive associations, e.g. between %EPA (eicosapentaenoic acid, 20:5: n3) and %AA (arachidonic acid, 20:4 n6). Aim: To explain further correlations between relative amounts of eicosanoid and docosanoid precursors. Methods: Typically, the precursors had low numbers and low variability, as compared with the predominant fatty acids, such as oleic acid (18:1 c9). We first present considerations concerning associations in general between relative amounts of three positive scale variables, two of which (A, B) having narrow ranges relative to the third one (C). Next, we show results of computer experiments to test the reasoning. Results and Discussions: We made S = A + B + C, i.e. %A + %B + %C = 100. %A correlated positively with %B, whereas %A (%B) related negatively to %C. The particular ranges of A, B, and C seemed to explain these associations. We found that slope of %A (abscissa) vs. %B approached B/A. Furthermore, slope of %A (abscissa) vs. %C approached –(1 +B/A), and that of %B (abscissa) vs. %C was near –(1+ A/B). We also show equations of regression lines concerning associations between A (B, C) percentages of S, when ranges of A and B are narrow relative to C. Finally, we compare slope values obtained by the formulas, and by linear regression. Conclusions: We suggest that Intended Ranges of eicosanoid precursor fatty acids might have arisen through evolutionary selection, thereby causing Distribution Dependent Correlations, mathematically. Possibly, this selection could improve the balance between eicosanoids (docosanoids). Definitions and Abbreviations: Variability: the width or spread of a distribution, measured e.g. by the range and standard deviation. Distribution: graph showing the frequency distribution of a variable within a particular range. In this article, we also use distribution when referring to a particular range, a – b, on the scale. Uniform distribution: every value within the range is equally likely. In this article, we may write “Distributions of A, B, and C were a - b, c - d, and e - f, respectively”. OA = Oleic Acid (18:1 c9); LA = Linoleic Acid (18:2 n6); ALA = Alpha Linolenic Acid (18:3 n3); AA = Arachidonic Acid (20:4 n6); EPA = EicosaPentaenoic Acid (20:5 n3); DPA = DocosaPentaenoic Acid (22:5 n3); DHA = Docosa Hexaenoic Acid (22:6 n3); DGLA= Dihomo Gamma Linolenic Acid (20:3 n6); EDA = Eicosa Dienoic Acid (20:2 n6); ETA = Eicosa Trienoic acid (20:3 n3).

Potential Mechanism and Effects of Different Selenium Sources and Different Effective Microorganism Supplementation Levels on Growth Performance, Meat Quality, and Muscle Fiber Characteristics of Three-Yellow Chickens.

A trial was conducted to investigate the effects of different Se sources, including sodium selenite (S-Se) and selenium yeast (Y-Se) and different effective microorganism (EM) addition levels on growth performance, meat quality, and muscle fiber characteristics of three-yellow chickens and its potential mechanism. A total of 400 birds were randomly distributed into 4 groups (S-Se, S-Se + EM, Y-Se, and Y-Se + EM groups) consisting of a 2 × 2 factorial arrangement. The main factors were the source of Se (ISe = inorganic Se: 0.2 mg/kg S-Se; OSe = organic Se: 0.2 mg/kg Y-Se) and the level of EM (HEMB = high EM: 0.5% EM; ZEMB = low EM: 0% EM). Each treatment had 5 replicates and each replicate consisted of 20 broiler chickens. The trial lasted for 70 days. The results showed that, in breast muscle, the broiler chickens fed OSe source decreased the pH24h, drip loss, shear force, perimeter, cross-sectional area, and diameter, but increased the and density compared with the broiler chickens fed ISe source (p < 0.05); broiler chickens supplied with HEMB level decreased the cross-sectional area and diameter, but increased the pH24h, and density compared with the broiler chickens supplied with ZEMB level (p < 0.05). In thigh muscle, OSe source and HEMB level also could improve the meat quality and change muscle fiber characteristics of broiler chickens (p < 0.05). Meat quality was correlated with the muscle fiber characteristics (p < 0.05). OSe source and HEMB level could regulate the expression levels of muscle fiber-relative genes in the breast and thigh muscles (p < 0.05). In conclusion, OSe source and HEMB level could improve the meat quality of the breast and thigh muscles of three-yellow chickens by changing the muscle fiber characteristics, and they changed the muscle fiber characteristics by regulating the expression levels of muscle fiber-relative genes.

The regulating pathway of creatine on muscular protein metabolism depends on the energy state.

Creatine (Cr) is beneficial for increasing muscle mass and preventing muscle atrophy via involving in energy metabolism through the Cr and phosphocreatine (PCr) system. This study aimed to evaluate the supplemental effect of Cr on protein metabolism under normal and starvation conditions. The primary myoblasts were obtained from the breast muscle of chicks. The mammalian target of rapamycin (mTOR)/P70S6 kinase (P70S6K), ubiquitin-proteasome (UP) pathways, and mitochondrial function of myotubes were evaluated at normal or starvation state and with or without glucose supplementation. Under normal condition, Cr supplementation enhanced protein synthesis rate as well as upregulated the total and phosphorylated P70S6K expressions. Cr had little influence on protein catabolism and mitochondrial function. In a starvation state, however, Cr alleviated myotube atrophy and enhanced protein accretion by inhibiting Atrogin1 and myostatin (MSTN) expression. Furthermore, Cr treatment upregulated the transcriptional coactivators peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α) expression and decreased reactive oxygen species (ROS) accumulation under starvation condition. In the presence of glucose, however, the favorable effect of Cr on protein content and myotube diameter did not occur under starvation condition. The present result indicates that at a normal state, Cr stimulated protein synthesis via the mTOR/P70S6K pathway. In a starvation state, Cr mainly takes a favorable effect on protein accumulation via suppression of the UP pathway and mediated mitochondrial function mainly by serving as an energy supplier. The result highlights the potential clinical application for the modulation of muscle mass under different nutritional conditions.

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

BackgroundThe 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.ResultsA 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.ConclusionsThis 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.

MiR-30a-3p can inhibit the proliferation and promote the differentiation of chicken primary myoblasts

ABSTRACT 1. Chicken muscle is an important factor in meat quality and its development is controlled by a complex regulatory network. 2. The following study examined the expression of miR-30a-3p in Gushi chicken breast muscle tissue and found that it was differentially expressed at different embryonic stages, reaching a peak in the 14-day-old embryo (E14). 3. The effect of miR-30a-3p on chicken primary myoblasts (CPMs) was explored. Results from both cell counting kit-8 (CCK-8) and 5-ethynyl-2’-deoxyuridine (EdU) showed that this can inhibit the proliferation of myoblasts, and through cell cycle experiments, the inhibition of myoblast proliferation was found, which may be due to G0/G1 arrest in the cell cycle. 4. The effect of miR-30a-3p on the differentiation of myoblasts was studied. The results showed that miR-30a-3p can promote the expression of MYOD, myogenin (MYOG), and myosin heavy chain (MYHC) genes to promote the differentiation of myoblasts. Through MYHC protein immunofluorescence experiments, it was found that miR-30a-3p can effectively increase the area of myotubes. 5. Finally, mRNA transcriptome data was analysed, which showed that miR-30a-3p has 51 potential target genes. Among them, forkhead box O3 (FOXO3), ankyrin repeat domain 1 (ANKRD1), and insulin-induced 1 (INSIG1) genes were differentially expressed at different developmental stages and were enriched in Gene Ontology (GO) terms, such as cell differentiation and cellular developmental process. The data showed that tyrosine 3-monooxygenase/tryptophan 5-monooxygenase activation protein gamma (YWHAG), BUB1 mitotic checkpoint serine/threonine kinase (BUB1), and growth arrest and DNA damage-inducible 45 (GADD45) genes were enriched in the cell cycle pathway. 6. It can be speculated that miR-30a-3p plays roles through these genes in myoblast development. This research provides information for further improving knowledge of the chicken muscle development regulation network.

Effect of expression of PPARG, DNM2L, RRAD, and LINGO1 on broiler chicken breast muscle satellite cell function

Disorders affecting the breast muscle of modern commercial broiler chickens have increased in recent years. Wooden Breast (WB) myopathy is characterized by a palpably hard breast muscle with increased fat deposition. WB is a metabolic disorder with lipid accumulation considered to be a primary causal factor. The adult myoblasts, satellite cells, are a partially differentiated stem cell population and primarily function in muscle growth and regeneration. The satellite cells also express adipogenic genes. The objective of this study was to determine the expression of the adipogenic genes PPARG, DNM2L, RRAD, and LINGO1 in commercial Ross 708 (708) and Randombred (RBch) satellite cells. RBch satellite cells are from commercial 1995 broilers before WB and 708 broilers are a modern commercial line. In general, expression of these genes was different between the 708 and RBch satellite cells during proliferation and differentiation. Expression of PPARG and RRAD were both significantly increased during both proliferation and differentiation in the 708 cells (P ≤ 0.05). Knocking down the expression of these genes with small interfering RNAs did not greatly affect either proliferation or differentiation. Lipid accumulation was affected by the knockdown of these genes with significant line effects from 48 h of proliferation through 72 h of differentiation. In general, 708 satellite cells had higher lipid levels. Knockdown treatment effect was specific to each gene. The results demonstrate that lipid biosynthesis has been affected in breast muscle satellite cells which may contribute to the increased lipid deposition in modern day commercial broiler chickens.

도계 중 할랄방법에 CO2와 N2 가스기절처리가 닭 가슴살과 내장의 물리화학적 특성에 미치는 영향

We investigated the effects of stunning methods and gas treatments during slaughter on the quality characteristics of chicken breast and small intestine. Broilers (Ross 308) were stunned and slaughtered using halal, CO₂, or N₂ gas stunning methods (for 10 birds). After slaughter, the pH, proximate composition, color, water-holding capacity, cooking loss, and shear force of chicken breast muscle and small intestine were determined. Compared with the halal treatment, CO₂ treatment resulted in higher pH and lower cooking loss (<i>P</i>&lt;0.05), and the pH, color, and shear force of chicken breast muscle with N₂ treatment were similar to those of the halal treatment (<i>P</i>&gt;0.05). Compared with the halal treatment, the gas treatments resulted in lower pH and lightness and higher redness, yellowness, thickness, and shear force of the small intestine (<i>P</i>&lt;0.05). However, compared with the CO₂ treatment, the N₂ treatment resulted in lower pH, redness, and yellowness, and higher lightness, thickness, and shear force. Overall, compared with the halal method, our results suggest that the use of N₂ gas suppresses the discoloration and deterioration of the texture of chicken meat and small intestine caused by CO₂ gas treatment in the gas stunning method.

CircCCDC91 regulates chicken skeletal muscle development by sponging miR-15 family via activating IGF1-PI3K/AKT signaling pathway

Circular RNAs (circRNAs) has been reported in various tissues of animals and associated with multiple biological processes. From our previous sequencing data, we found a novel circRNA, circCCDC91 which was generated from exon 2 to 8 of the CCDC91 gene. We observed that circCCDC91 was differentially expressed in the chicken breast muscle among 4 different embryonic developmental time points (embryonic day 10 [E10], E13, E16, and E19). Therefore, we assumed that circCCDC91 have a potential function in chicken skeletal muscle development. In this study, we firstly verify the annular structure and expression pattern of circCCDC91, and further investigate on whether circCCDC91 could promote chicken skeletal development. Mechanistically, circCCDC91 could absorb miR-15a, miR-15b-5p, and miR-15c-5p to modulate the expression of Insulin receptor substrate1 (IRS1), as well as activate insulin-1ike growth factor 1-phosphatidylinositol 3-kinase/AKT (IGF1-PI3K/AKT) signaling pathway. In addition, circCCDC91 could rescue skeletal muscle atrophy by activating IGF1-PI3K/AKT pathway. Taken together, the findings in this study revealed that the newly identified circCCDC91 promotes myoblasts proliferation and differentiation, and alleviates skeletal muscle atrophy by directly binding to miR-15 family via activating IGF1-PI3K/AKT signaling pathway in chicken.

Effects of quercetin on tenderness, apoptotic and autophagy signalling in chickens during post-mortem ageing

The effect of quercetin on chicken breast muscle tenderness and the associated mechanism were investigated. The results indicated that quercetin significantly decreased the shear force and increased the myofibril fragmentation index (MFI). Haematoxylin-eosin-stained images showed that the internal structure of myofibril bundles in the quercetin-treated group was obviously degraded. Transmission electron microscopy showed that the myofibril structure, especially the M-line and A-band, was seriously degraded after quercetin treatment. Furthermore, quercetin treatment increased caspase-3 activity and the Bax/Bcl-2 ratio. The intensity of BiP, XBP1 and p-IRE1/IRE1 ratio increased significantly, and caspase-12 was activated. In addition, quercetin induced the transition from LC3I to LC3II and increased the expression of ATG7 and Beclin-1. The PI3K/Akt/mTOR signalling pathway was involved in the induction of autophagy and apoptosis by quercetin. These results indicated quercetin can promote meat tenderization, and activate apoptosis and autophagy pathways during post-mortem ageing.