Chicken Breast Muscle Research Articles

FOSL2 Is Involved in the Regulation of Glycogen Content in Chicken Breast Muscle Tissue.

The glycogen content in muscle of livestock and poultry animals affects the homeostasis of their body, growth performance, and meat quality after slaughter. FOS-like 2, AP-1 transcription factor subunit (FOSL2) was identified as a candidate gene related to muscle glycogen (MG) content in chicken in our previous study, but the role of FOSL2 in the regulation of MG content remains to be elucidated. Differential gene expression analysis and weighted gene coexpression network analysis (WGCNA) were performed on differentially expressed genes (DEGs) in breast muscle tissues from the high-MG-content (HMG) group and low-MG-content (LMG) group of Jingxing yellow chickens. Analysis of the 1,171 DEGs (LMG vs. HMG) identified, besides FOSL2, some additional genes related to MG metabolism pathway, namely PRKAG3, CEBPB, FOXO1, AMPK, and PIK3CB. Additionally, WGCNA revealed that FOSL2, CEBPB, MAP3K14, SLC2A14, PPP2CA, SLC38A2, PPP2R5E, and other genes related to the classical glycogen metabolism in the same coexpressed module are associated with MG content. Also, besides finding that FOSL2 expression is negatively correlated with MG content, a possible interaction between FOSL2 and CEBPB was predicted using the STRING (Search Tool for the Retrieval of Interacting Genes) database. Furthermore, we investigated the effects of lentiviral overexpression of FOSL2 on the regulation of the glycogen content in vitro, and the result indicated that FOSL2 decreases the glycogen content in DF1 cells. Collectively, our results confirm that FOSL2 has a key role in the regulation of the MG content in chicken. This finding is helpful to understand the mechanism of MG metabolism regulation in chicken and provides a new perspective for the production of high-quality broiler and the development of a comprehensive nutritional control strategy.

Promising Role of Growth Hormone-Boosting Peptide in Regulating the Expression of Muscle-Specific Genes and Related MicroRNAs in Broiler Chickens.

Simple SummaryIn chickens, breast muscle is a key contributor to meat yield. Skeletal muscle development is a complex process regulated by many genes, transcription factors, and miRNA through different muscle signaling pathways. The latter are activated by synthetic growth hormone-boosting peptides (GHBP) that mimic the effects of endogenous growth factors, mainly insulin-like growth factor-1 (IGF-1)/mammalian target of rapamycin (mTOR), and modulate myostatin gene expression. The molecular mechanisms underlying chicken breast muscle development in relation to GHBP are still unclear. In the current study, the role of GHBP in a chicken’s growth rate, skeletal muscle development-related genes and myomiRs, serum bio-chemical parameters, and myofiber characteristics post-hatching was evaluated. Using of GHBP at a level of 200 μg/kg positively regulated gene expression related to muscle growth and muscle-specific myomiRs. This was evidenced by upregulation of IGF-1, mTOR, myoD and myogenin genes, and miR-27b and miR-499 and downregulation of myostatin, Pax-3 and -7 genes and miR-1a, miR-133a, miR-133b, and miR-206 compared to the control group. Therefore, administration of GHBP at the level of 200 μg/kg to broiler chicks can accelerate their growth by enhancing skeletal muscle development via controlling the transcription of breast muscle-related genes and associated myomiRs.Appropriate skeletal muscle development in poultry is positively related to increasing its meat production. Synthetic peptides with growth hormone-boosting properties can intensify the effects of endogenous growth hormones. However, their effects on the mRNA and miRNA expression profiles that control muscle development post-hatching in broiler chicks is unclear. Thus, we evaluated the possible effects of synthetic growth hormone-boosting peptide (GHBP) inclusion on a chicken’s growth rate, skeletal muscle development-related genes and myomiRs, serum biochemical parameters, and myofiber characteristics. A total of 400 one-day-old broiler chicks were divided into four groups supplied with GHBP at the levels of 0, 100, 200 and 300 μg/kg for 7 days post-hatching. The results showed that the highest levels of serum IGF-1 and GH at d 20 and d 38 post-hatching were found in the 200 μg/kg GHBP group. Targeted gene expression analysis in skeletal muscle revealed that the GHBP effect was more prominent at d 20 post-hatching. The maximum muscle development in the 200 μg/kg GHBP group was fostered by the upregulation of IGF-1, mTOR, myoD, and myogenin and the downregulation of myostatin and the Pax-3 and -7 genes compared to the control group. In parallel, muscle-specific myomiR analysis described upregulation of miR-27b and miR-499 and down-regulation of miR-1a, miR-133a, miR-133b, and miR-206 in both the 200 and 300 μg/kg GHBP groups. This was reflected in the weight gain of birds, which was increased by 17.3 and 11.2% in the 200 and 300 μg/kg GHBP groups, respectively, when compared with the control group. Moreover, the maximum improvement in the feed conversion ratio was achieved in the 200 μg/kg GHBP group. The myogenic effects of GHBP were also confirmed via studying myofiber characteristics, wherein the largest myofiber sizes and areas were achieved in the 200 μg/kg GHBP group. Overall, our findings indicated that administration of 200 μg/kg GHBP for broiler chicks could accelerate their muscle development by positively regulating muscle-specific mRNA and myomiR expression and reinforcing myofiber growth.

In-feed organic and inorganic manganese supplementation on broiler performance and physiological responses.

ObjectiveA trial was conducted to investigate the effects of supplemental levels of Mn provided by organic and inorganic trace mineral supplements on growth, tissue mineralization, mineral balance, and antioxidant status of growing broiler chicks.MethodsA total of 500 male chicks (8-d-old) were used in 10-day feeding trial, with 10 treatments and 10 replicates of 5 chicks per treatment. A 2×5 factorial design was used where supplemental Mn levels (0, 25, 50, 75, and 100 mg Mn/kg diet) were provided as MnSO4·H2O or MnPro. When Mn was supplied as MnPro, supplements of zinc, copper, iron, and selenium were supplied as organic minerals, whereas in MnSO4·H2O supplemented diets, inorganic salts were used as sources of other trace minerals. Performance data were fitted to a linear-broken line regression model to estimate the optimal supplemental Mn levels.ResultsManganese supplementation improved body weight, average daily gain (ADG) and feed conversion ratio (FCR) compared with chicks fed diets not supplemented with Mn. Manganese in liver, breast muscle, and tibia were greatest at 50, 75, and 100 mg supplemental Mn/kg diet, respectively. Higher activities of glutathione peroxidase and superoxide dismutase (total-SOD) were found in both liver and breast muscle of chicks fed diets supplemented with inorganic minerals. In chicks fed MnSO4·H2O, ADG, FCR, Mn balance, and concentration in liver were optimized at 59.8, 74.3, 20.6, and 43.1 mg supplemental Mn/kg diet, respectively. In MnPro fed chicks, ADG, FCR, Mn balance, and concentration in liver and breast were optimized at 20.6, 38.0, 16.6, 33.5, and 62.3 mg supplemental Mn/kg, respectively.ConclusionLower levels of organic Mn were required by growing chicks for performance optimization compared to inorganic Mn. Based on the FCR, the ideal supplemental levels of organic and inorganic Mn in chick feeds were 38.0 and 74.3 mg Mn/kg diet, respectively.

Breast muscle and plasma metabolomics profile of broiler chickens exposed to chronic heat stress conditions

Understanding the variations of muscle and plasma metabolites in response to high environmental temperature can provide important information on the molecular mechanisms related to body energy homeostasis in heat-stressed broiler chickens. In this study, we investigated the effect of chronic heat stress conditions on the breast muscle (Pectoralis major) and plasma metabolomics profile of broiler chickens by means of an innovative, high-throughput analytical approach such as the proton nuclear magnetic resonance (1H NMR) spectrometry. A total of 300 Ross 308 male chicks were split into two experimental groups and raised in either thermoneutral conditions for the entire rearing cycle (0–41 days) (TNT group; six replicates of 25 birds/each) or exposed to chronic heat stress conditions (30 °C for 24 h/day) from 35 to 41 days (CHS group; six replicates of 25 birds/each). At processing (41 days), plasma and breast muscle samples were obtained from 12 birds/experimental group and then subjected to 1H NMR analysis. The reduction of BW and feed intake as well as the increase in rectal temperature and heterophil: lymphocyte ratio confirmed that our experimental model was able to stimulate a thermal stress response without significantly affecting mortality. The 1H NMR analysis revealed that a total of 26 and 19 molecules, mostly related to energy and protein metabolism as well as antioxidant response, showed significantly different concentrations respectively in the breast muscle and plasma in response to the thermal challenge. In conclusion, the results obtained in this study indicated that chronic heat stress significantly modulates the breast muscle and plasma metabolome in fast-growing broiler chickens, allowing to delineate potential metabolic changes that can have important implications in terms of body energy homeostasis, growth performance and product quality.

Correlation between instrumental stress and oral processing property of chicken broiler breast under wooden breast myopathy

SummaryWooden breast myopathy affects the quality of fresh and processed chicken breast muscle. The objective of this study was to construct a classification method by instrumental stress, and the effects of wooden breast myopathy on meat quality and oral processing property, and was to explore correlations between stress and oral processing parameters. The severity of wooden breast myopathy was highly correlated to fillet weight (R2 = 0.740), thickness (R2 = 0.826) and hardness (R2 = 0.803) (P < 0.01). The 3D scatter model based on stress is robust and reliable to classify the fillets into four categories (normal, mild, moderate and severe wooden breast fillets), avoiding manual grading. Moisture, fat, collagen, pH, drip loss, cooking loss, thawing loss, purge loss, hardness, gumminess and chewiness significantly increased with the severity of wooden breast myopathy, whereas fat, ash and water/salt‐soluble protein contents significantly decreased (P < 0.05). Shear force reached the maximum (36.32 N) when this myopathy was moderate. The myopathy led to an increase in masseter activity and the particle size of the bolus. Significantly higher correlations between stress, Dx(50) (R2 = 0.790), Dx(90) (R2 = 0.771) and D[4,3] (R2 = 0.797) were found (P < 0.01). This study also showed that jaw movement and muscle activity could be used to understand the links between physical property and orally sensory property.

Body Weight Gain and Carcass Quality of the Hybrid Chicken Derived from the Crossing between Female F1 Kampung Super and Male F1 Kampung-Broiler

This research was conducted to observe the body weight gain and carcass quality of the hybrid chicken derived from the crossing between female F1 Kampung Super and male F1 Kampung-Broiler. The weekly weight gain for seven weeks and carcass quality, including breast yield, protein content, lipid content, moisture, and pH were measured with each group consists of six individuals. The chickens were slaughtered for meat quality measurements on the 7th week. The results showed that the hybrid chickens’ weight at the 7th week (888.22±139.63) was higher than layer (467.06±85.7) and pelung (436.39±42.33). The hybrid chicken’s breast yield (3.20%) was significantly higher than pelung’s (1.66%). These characteristics of hybrid chicken breast muscle lead to the conclusion that hybrid chicken is a potential alternative meat-type chicken with local chicken meat characteristics and has relatively fast growth.

Transcriptome Analysis Reveals the Profile of Long Non-coding RNAs During Chicken Muscle Development.

The developmental complexity of muscle arises from elaborate gene regulation. Long non-coding RNAs (lncRNAs) play critical roles in muscle development through the regulation of transcription and post-transcriptional gene expression. In chickens, previous studies have focused on the lncRNA profile during the embryonic periods, but there are no studies that explore the profile from the embryonic to post-hatching period. Here, we reconstructed 14,793 lncRNA transcripts and identified 2,858 differentially expressed lncRNA transcripts and 4,282 mRNAs from 12-day embryos (E12), 17-day embryos (E17), 1-day post-hatch chicks (D1), 14-day post-hatch chicks (D14), 56-day post-hatch chicks (D56), and 98-day post-hatch chicks (D98), based on our published RNA-seq datasets. We performed co-expression analysis for the differentially expressed lncRNAs and mRNAs, using STEM, and identified two profiles with opposite expression trends: profile 4 with a downregulated pattern and profile 21 with an upregulated pattern. The cis- and trans-regulatory interactions between the lncRNAs and mRNAs were predicted within each profile. Functional analysis of the lncRNA targets showed that lncRNAs in profile 4 contributed to the cell proliferation process, while lncRNAs in profile 21 were mainly involved in metabolism. Our work highlights the lncRNA profiles involved in the development of chicken breast muscle and provides a foundation for further experiments on the role of lncRNAs in the regulation of muscle development.

Neuropeptide Y and its receptors are expressed in chicken skeletal muscle and regulate mitochondrial function

Neuropeptide Y (NPY) is a highly conserved 36-amino acid neurotransmitter, which is primarily expressed in the mammalian arcuate nucleus of the hypothalamus. It is a potent orexigenic neuropeptide, stimulating appetite and inducing feed intake in a variety of species. Recent research has shown that NPY and its receptors can be expressed by peripheral tissues, but their role is not yet well defined. Specifically, this information is particularly sparse in avian species. Therefore, the aim of this study was to determine the expression of NPY and its receptors, and determine their regulation by environmental and nutritional stressors, in the skeletal muscle of avian species using in vivo and in vitro approaches. Here, we show that NPY and its receptors are expressed in chicken breast and leg muscle as well as in quail myoblast (QM7) cell line. Intraperitoneal injection of recombinant NPY increased feed intake in 9-d old chicks and upregulated the expression of NPY and NPY receptors in breast and leg muscle, suggesting autocrine and/or paracrine roles for NPY. Additionally, NPY is able to modulate the mitochondrial network. In breast muscle, a low dose of NPY upregulated (P < 0.05) the expression of genes involved in ATP production (uncoupling protein, UCP; nuclear factor erythroid 2 like 2, NFE2L2) and dynamics (mitofusin 1, MFN1), while a high dose decreased (P < 0.05) markers of mitochondrial dynamics (mitofusin 2, MFN2; OPA1 mitochondrial dynamin like GTPase, OPA1) and increased (P < 0.05) genes involved in mitochondrial biogenesis (D-loop, peroxisome proliferator activated receptor gamma, PPARG). In leg muscle, NPY decreased (P < 0.05) markers of mitochondrial biogenesis and ATP synthesis (D-loop; peroxisome proliferator activated receptor alpha, PCG1A; peroxisome proliferator-activated receptor gamma, coactivator 1 beta, PPARGC1B; PPARG; NFE2L2). In QM7 cells, genes associated with mitochondrial biogenesis, dynamics, and ATP synthesis were all upregulated (P < 0.05), even though basal respiration and ATP production were decreased (P < 0.05) with NPY treatment as measured by XF Flux analysis. Together, these data show that the NPY system is expressed in avian skeletal muscle and plays a role in mitochondrial function.

Effectiveness of ultrasound‐assisted immersion thawing on the thawing rate and physicochemical properties of chicken breast muscle

This study evaluated the effect of air thawing (AT), water thawing (WT), and ultrasound-assisted immersion thawing (UT) at different power levels (200, 300, 400, and 500 W) on the thawing rate, physicochemical properties, and protein structure of chicken breast muscle (pectoralis), and the weight of each sample was approximately 106 ± 3g. UT shortened the total thawing time and decreased the cutting force with increasing ultrasound power. Additionally, UT at 300 W (UT-300) remarkably reduced the thawing and cooking losses of the samples compared to AT, WT, and other UT powers (p<0.05). Low-field nuclear magnetic resonance spectroscopy showed that the T21 and T22 of the UT-300 samples were shorter than those of the AT and WT samples (p<0.05), which revealed that UT-300 reduced the mobility and losses of both immobilized and free water. Moreover, UT-300 remarkably reduced the damage to the myofibrillar protein (MP) structure. Overall, with appropriate ultrasonic power, the thawing rate increased and changes in the MP structure were reduced. PRACTICAL APPLICATION: This study found that compared to that of AT samples, the thawing time of the UT-300 samples markedly decreased by 57%. In addition, UT-300 could reduce the damage to the myofibrillar protein structure, which was very beneficial for further processing of frozen foods.

The Effect of Rosemary (Rosmarinus officinalis) and Blackcurrant Extracts (Ribes nigrum) Supplementation on Performance Indices and Oxidative Stability of Chicken Broiler Meat

Simple SummaryThe common practice of supplementing broiler feeds with oils rich in omega-3 fatty acids to improve the ratio of omega-6 to omega-3 fatty acids in chicken muscles results in a reduced oxidative stability of the meat and accelerated intensity of lipid peroxidation during storage. This study evaluated the effects of commercial rosemary (RO) and blackcurrant (BC) extracts rich in polyphenolic antioxidants added to broiler diets on the oxidative stability of meat and chicken production parameters. In this study, 120 one-day-old male Hubbard Flex broiler chicks were randomly allocated to 5 experimental groups, and for 35 days, were fed control starter and grower diets or the same basal diets containing two concentrations (2.5 and 5 g/kg) of the RO or BC extracts. The inclusion of RO and BC in the birds’ diet had no significant effect on broiler weight gain, feed conversion ratio, or carcass characteristics. The enrichment of chicken diet with RO and BC did not affect the oxidative stability of chicken breast muscles, but reduced the malondialdehyde (MDA) formation in frozen thigh muscles.The effects of dietary supplementation with extracts of rosemary (RO) and blackcurrant (BC) on the performance indices and the oxidative stability of broiler meat were investigated during a 35-d experiment. For the experiment, 120 one-day-old male Hubbard Flex broiler chicks were randomly allocated to 5 experimental groups (control group and 4 treatments, each in 6 replications, 24 birds per group, 4 birds per replicate) and fed control starter and grower diets or basal diets containing two concentrations (2.5 and 5 g/kg) of the RO and BC extracts. Basic performance traits (body weight gain, feed intake, feed conversion) were recorded during the trial. At the end of the experiment, pectoral and thigh muscles were collected. Thiobarbituric acid (TBA) assays using the muscles samples were performed after 1 and 5 d of chilling (4 °C) and after 90 d of frozen storage (−18 °C). The inclusion of RO and BC in the birds’ diet had no significant effects on weight gain and feed conversion ratio of chickens, or on carcass characteristics, compared with control group. Enrichment of chicken diet with RO and BC did not affect the oxidative stability of chicken breast muscles, but the tested extracts significantly reduced the malondialdehyde (MDA) formation in frozen thigh muscles.

Assessment of Physicochemical Characteristics and Microbiological Quality in Broiler Chicken Breast Muscle (Pectoralis major) Subjected to Different Temperatures and Lengths of Cold Transportation.

Cold truck transportation is considered one of the most integral parts in a food processing chain. However, countless cases of product spoilage and food poisoning incidents have proven that temperature control during transport has been neglected. Literature on the impact of temperature during distribution is scarce. The objective of this study was to investigate the impact of various transportation temperatures and travel duration on the meat quality and microbial population of broiler chicken breast muscle. Sixty broiler chickens (42 days old) were slaughtered and eviscerated; they then had their breast muscles removed (each bird provided two breast muscle samples: left breast and right breast), which were wrapped in plastic film. All 120 packed boneless breasts (PBBs) were then placed at −18 °C for 24 h. After 24 h, the 60 PBB samples were subjected to transportation for 1 h at 4 °C (20 PBBs), 10 °C (20 PBBs), and 15 °C (20 PBBs) while the remaining 60 samples were transported for 5 h at 4 °C (20 PBBs), 10 °C (20 PBBs), and 15 °C (20 PBBs) before analyses. The samples transported at higher temperatures exhibited higher populations of coliform and Salmonella than those transported at lower temperatures. A significant impact of the transportation duration on the Salmonella population was only observed in samples transported at 4 °C for 5 h. However, a significant impact of transportation temperature on color was only recorded for the redness (a*) values, where the samples transported at higher temperatures exhibited higher redness (a*) values. Significant increases in lightness (L*) and yellowness (b*) values as well as decreases in redness (a*) and pH values were recorded in samples subjected to longer durations of transportation across all the temperatures observed in this study.

Comprehensive Proteomic Characterization of the Pectoralis Major at Three Chronological Ages in Beijing-You Chicken.

Chronological age is one of the important factors influencing muscle development and meat quality in chickens. To evaluate the protein expression profiles during skeletal muscle development, we performed a tandem mass tag (TMT)-based quantitative proteomic strategy in pectoralis major (breast muscle) of Beijing-You chicken (BYC) at the chronological age of 90, 120, and 150 days. Each chronological age contained 3 pooling samples or 15 birds (five birds per pooling sample). A total of 1,413 proteins were identified in chicken breast muscle with FDR < 1% and 197 of them were differentially expressed (fold change ≥1.2 or ≤0.83 and p < 0.05). There were 110 up- and 71 down-regulated proteins in 120 d vs 90 d group, 13 up- and 10 down-regulated proteins in 150 d vs 120 d group. The proteomic profiles of BYC at 120 d were very similar to those at 150 d and highly different from those at 90 d, suggesting that 120 d might be an important chronological age for BYC. Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses indicated that these differentially expressed proteins were mainly involved in the pathway of glycolysis/gluconeogenesis, adrenergic signaling in cardiomyocytes, focal adhesion, oocyte meiosis and phagosome. Furthermore, some DEPs were quantified using parallel reaction monitoring (PRM) to validate the results from TMT analysis. In summary, these results provided some candidate protein-coding genes for further functional validation and contribute to a comprehensive understanding of muscle development and age-dependent meat quality regulation by proteins in chickens.

Study on the transcriptome for breast muscle of chickens and the function of key gene RAC2 on fibroblasts proliferation

BackgroundGrowth performance is significant in broiler production. In the growth process of broilers, gene expression varies at different growth stages. However, limited research has been conducted on the molecular mechanisms of muscle growth and development in yellow-feathered male chickens.ResultsIn the study, we used RNA-seq to study the transcriptome of the breast muscle of male Jinghai yellow chickens at 4 (M4F), 8 (M8F) and 12 weeks (M12F) of age. The results showed that 4608 differentially expressed genes (DEGs) were obtained by comparison in pairs of the three groups with Fold Change (FC) ≥ 2 and False Discovery Rate (FDR) ≤ 0.05, and 83, 3445 and 3903 DEGs were obtained separately from M4FvsM8F, M4FvsM12F and M8FvsM12F. Six genes were found as co-differentially expressed in the three age groups, namely SNCG, MYH1A, ARHGDIB, ENSGALG00000031598, ENSGALG00000035660 and ENSGALG00000030559. The GO analysis showed that 0, 304 and 408 biological process (BP) were significantly enriched in M4FvsM8F, M4FvsM12F and M8FvsM12F groups, respectively. KEGG pathway enrichment showed that 1, 2, 4 and 4 pathways were significantly enriched in M4FvsM8F, M4FvsM12F, M8FvsM12F and all DEGs, respectively. They were steroid biosynthesis, carbon metabolism, focal adhesion, cytokine-cytokine receptor interaction, biosynthesis of amino acids and salmonella infection. We constructed short hairpin RNA (shRNA) to interfere the differentially expressed gene RAC2 in DF-1 cells and detected mRNA and protein expression of the downstream genes PAK1 and MAPK8. Results of qPCR showed that RAC2, PAK1 and MAPK8 mRNA expression significantly decreased in the shRAC2–2 group compared with the negative control (NC) group. Western Blot (WB) results showed that the proteins of RAC2, PAK1 and MAPK8 also decreased in the shRAC2–2 group. Cell Counting Kit-8 (CCK-8) and 5-Ethynyl-2′-deoxyuridine (EdU) assay both showed that the proliferation of DF-1 cells was significantly inhibited after transfection of shRAC2–2.ConclusionsThe results of RNA-seq revealed genes, BP terms and KEGG pathways related to growth and development of male Jinghai yellow chickens, and they would have important guiding significance to our production practice. Further research suggested that RAC2 might regulate cell proliferation by regulating PAKs/MAPK8 pathway and affect growth of chickens.

Investigation of allele specific expression in various tissues of broiler chickens using the detection tool VADT

Differential abundance of allelic transcripts in a diploid organism, commonly referred to as allele specific expression (ASE), is a biologically significant phenomenon and can be examined using single nucleotide polymorphisms (SNPs) from RNA-seq. Quantifying ASE aids in our ability to identify and understand cis-regulatory mechanisms that influence gene expression, and thereby assist in identifying causal mutations. This study examines ASE in breast muscle, abdominal fat, and liver of commercial broiler chickens using variants called from a large sub-set of the samples (n = 68). ASE analysis was performed using a custom software called VCF ASE Detection Tool (VADT), which detects ASE of biallelic SNPs using a binomial test. On average ~ 174,000 SNPs in each tissue passed our filtering criteria and were considered informative, of which ~ 24,000 (~ 14%) showed ASE. Of all ASE SNPs, only 3.7% exhibited ASE in all three tissues, with ~ 83% showing ASE specific to a single tissue. When ASE genes (genes containing ASE SNPs) were compared between tissues, the overlap among all three tissues increased to 20.1%. Our results indicate that ASE genes show tissue-specific enrichment patterns, but all three tissues showed enrichment for pathways involved in translation.

Molecular characterization of a novel aspartyl aminopeptidase that contributes to the increase in glutamic acid content in chicken meat during cooking

The enzyme involved in the increase in glutamic acid content in chicken meat during cooking was identified and characterized. Chicken homogenate produced significantly more free glutamic acid and exhibited higher glutamyl p-nitroanilide (Glu-pNA) hydrolyzing activity than beef when heat cooked. Amino acid sequencing revealed the presence of aspartyl aminopeptidase (DNPEP) in chicken meat. Using RT-PCR, DNPEP gene expression was detected in chicken breast and thigh muscles, liver, and small intestine, together with various other peptidase genes. Full-length DNPEP cDNA was cloned, and recombinant chicken DNPEP (cDNPEP) was expressed in Escherichia coli. cDNPEP showed five-fold higher activity against Glu-pNA than against aspartyl-pNA, which represents a different substrate specificity than observed for recombinant bovine DNPEP (bDNPEP). The Km values of both DNPEPs with Glu p-NA substrates indicated a higher affinity of cDNPEP for glutamyl residues. This unique substrate specificity of cDNPEP contributes to efficient glutamic acid production in chickens.

Evaluation of the Effect of Aloe vera Extract on Aflatoxin B1 in Chicken Breast Muscle

Background & Aims of the Study: Among aflatoxins, aflatoxin B1 (AFB1) is more toxic and dangerous. The presence of AFB1 in poultry feed is one of the most critical health and economic problems in the poultry industry. The critical concern caused by AFB1 contamination in the poultry industry is the transfer of toxins from the poultry feed to its products, such as meat, eggs, and edible parts. Thus, developing scientific strategies for controlling aflatoxin in poultry nutrition and protecting public health is very important. The present study aimed to evaluate the efficacy of Aloe vera extract in reducing the harmful effects of AFB1.Materials & MethodsIn this study, broilers were selected and divided into three groups. Group 1 is the negative control group, received a basal diet. Group 2 is the positive control group, received a diet supplemented with AFB1. Group 3 was administered AFB1 and 100 ppm Aloe vera powder mixed in their diet. At the end of the experiment (Day 28), the birds were humanely euthanized, and their breast meat samples were collected. The toxin residue in muscles was measured by a commercial AFB1 detection kit.ResultsNo toxin was detected in the negative control group. In the third group, the residual amount of toxin was decreased by treating Aloe vera, but this difference was not significant. Significant differences are likely to be observed at higher doses.ConclusionSupplementation of the diet containing AFB1 with Aloe vera extract effectively reduced the adverse effects of AFB1 and could be a helpful solution for the aflatoxicosis problem.

LncRNAs and their regulatory networks in breast muscle tissue of Chinese Gushi chickens during late postnatal development

BackgroundChicken skeletal muscle is an important economic product. The late stages of chicken development constitute the main period that affects meat production. LncRNAs play important roles in controlling the epigenetic process of growth and development. However, studies on the role of lncRNAs in the late stages of chicken breast muscle development are still lacking. In this study, to investigate the expression characteristics of lncRNAs during chicken muscle development, 12 cDNA libraries were constructed from Gushi chicken breast muscle samples from 6-, 14-, 22-, and 30-week-old chickens.ResultsA total of 1252 new lncRNAs and 1376 annotated lncRNAs were identified. Furthermore, 53, 61, 50, 153, 117, and 78 DE-lncRNAs were found in the W14 vs. W6, W22 vs. W14, W22 vs. W6, W30 vs. W6, W30 vs. W14, and W30 vs. W22 comparison groups, respectively. After GO enrichment analysis of the DE-lncRNAs, several muscle development-related GO terms were found in the W22 vs. W14 comparison group. Moreover, it was found that the MAPK signaling pathway was one of the most frequently enriched pathways in the different comparison groups. In addition, 12 common target DE-miRNAs of DE-lncRNAs were found in different comparison groups, some of which were muscle-specific miRNAs, such as gga-miR-206, gga-miR-1a-3p, and miR-133a-3p. Interestingly, the precursors of four newly identified miRNAs were found to be homologous to lncRNAs. Additionally, we found some ceRNA networks associated with muscle development-related GO terms. For example, the ceRNA networks contained the DYNLL2 gene with 12 lncRNAs that targeted 2 miRNAs. We also constructed PPI networks, such as IGF-I-EGF and FZD6-WNT11.ConclusionsThis study revealed, for the first time, the dynamic changes in lncRNA expression in Gushi chicken breast muscle at different periods and revealed that the MAPK signaling pathway plays a vital role in muscle development. Furthermore, MEF2C and its target lncRNA may be involved in muscle regulation through the MAPK signaling pathway. This research provided valuable resources for elucidating posttranscriptional regulatory mechanisms to promote the development of chicken breast muscles after hatching.

Growth performance, carcass characteristics, and fatty acid composition of breast and thigh meat of broiler chickens fed gradually increasing levels of supplemental blueberry extract.

The effect of gradually increasing supplemental levels of blueberry extract on growth performance, carcass characteristics, and fatty acid composition of breast and thigh muscles of broiler chickens was investigated. One hundred ninety-two 7-day-old chickens were randomly distributed into four groups having four replicates with 12 birds in each replicate. Basal diets were prepared for starter (days 8 to 21) and finisher (days 22 to 42). Basal diets were offered to the control group only, whereas other treatments received basal diets fortified with 0.5, 1, and 2% blueberry extract (BB0.5, BB1, and BB2 groups, respectively). The duration of experiment was 35days (days 8 to 42). During finisher and overall growth phases, broilers in the BB2 group had greater body weight gain than those in the BB0.5 and control groups, whereas the BB1 group had higher body weight gain than the control group (P < 0.001). Body weight gain remained unaffected during the starter phase. Feed intake was greater in the BB2 group than in the control group at days 8 to 21, 22 to 42, and 8 to 42 (P = 0.002, P = 0.035, and P = 0.001, respectively). The control group had poor FCR than the BB2 group in the starter phase (P = 0.034). At days 22 to 42, feeding blueberry extract (BB0.5, BB1, and BB2) improved the FCR of broilers compared with the control group, whereas the BB2 group had better FCR than the BB0.5 group (P < 0.001). At 8 to 42days, broilers in the control group had poor FCR compared with the BB1 and BB2 groups, whereas the BB0.5 group had poor FCR than the BB2 group (P < 0.001). Slaughter weight was lower in the control group than in the blueberry extract groups, whereas the BB2 group had greater slaughter weight than the BB0.5 group (P < 0.001). Dressing percentage of broilers in the control and BB0.5 groups was lower than that in other groups (P < 0.001). Gizzard yield was higher in the BB0.5 and BB2 groups than in the control group (P = 0.021). In addition, feeding 2% blueberry extract increased the concentration of different fatty acids in breast and thigh meat of broiler chickens. Findings suggest that feeding 2% blueberry extract may improve growth performance, carcass characteristics, and fatty acid composition of breast and thigh muscles of broilers.

Effect of ice-temperature storage on some properties of salt-soluble proteins and gel from chicken breast muscles

ABSTRACT The changes in physicochemical properties of salt-soluble proteins and gel prepared with chicken breast muscles during −1.5oC (ice-temperature) and 4oC (refrigerated temperature) storage were investigated. Compared with the samples of 4oC stored group, the decrease in solubility, the content of total sulfhydryl and available sulfhydryl groups of SSP from chicken breast muscles at −1.5oC storage was effectively delayed, and the increase of both surface hydrophobicity and content of disulfide bond was obviously inhibited. The gel prepared with −1.5oC stored samples had much higher holding capacity of water, lower cooking loss, better springiness, and more uniform three-dimensional network structures with smaller-sized pores than those from 4°C stored-samples. Additionally, great changes in the proportions of non-flowing water and free water ratio were observed during 4oC storage. In short, the ice-temperature storage used for chicken meat preservation was better than refrigerated storage.

Changes in phosphorylation of chicken breast muscle in response to L-histidine introduction under low-NaCl conditions

ABSTRACT In an attempt to positively regulate meat quality at low NaCl concentration, the influence of L-histidine (L-his) introduction on the postmortem phosphorylation of chicken breast muscle protein that had been cured for 16 h at 1% NaCl was investigated at 90 min postmortem in the present study. The 633 different phosphoproteins (﹥1.2-fold) induced by L-his introduction during salting were identified, and a majority of these proteins were involved in glycolysis, calcium signalling pathway and muscle contraction. Myosin, actin, titin, troponin C (TnC), myosin light-chain kinase (MLCK) and γ-phosphorylase kinase (γ-PHK) were the main differentially expressed proteins (DEPs) that were associated with muscle contraction. An advantageous regulation of phosphoglucomutase-1 phosphorylation, fructose-1,6-bisphosphatase and pyruvate dehydrogenase E1 component was obtained in glycolytic metabolism after treatment with L-his.