Muscle Of Broilers Research Articles

Effects of dietary lycopene supplementation on serum biochemistry, meat quality and oxidative stability of breast muscle in broilers

Effects of dietary lycopene supplementation on serum biochemistry, meat quality and oxidative stability of breast muscle in broilers

Dietary Tributyrin Improves Growth Performance, Meat Quality, Muscle Oxidative Status, and Gut Microbiota in Taihe Silky Fowls under Cyclic Heat Stress.

Heat stress adversely affects poultry production and meat quality, leading to economic losses. This study aimed to investigate the effects of adding tributyrin on growth performance, meat quality, muscle oxidative status, and gut microbiota of Taihe silky fowls under cyclic heat stress (CHS) conditions. In this study, 120-day-old Taihe silky fowls (male) were randomly divided into six dietary treatments. These treatments included a normal control treatment (NC, fed a basal diet), a heat stress control treatment (HS, fed a basal diet), and HS control treatments supplemented with 0.04%, 0.08%, 0.16%, and 0.32% tributyrin, respectively. The NC treatment group was kept at 24 ± 1 °C, while the HS treatment birds were exposed to 34 ± 1 °C for 8 h/d for 4 weeks. Results showed that CHS decreased growth performance and compromised the meat quality of broilers (p < 0.05). However, tributyrin supplementation improved ADG and FCR in broilers exposed to CHS (p < 0.05). Additionally, tributyrin supplementation resulted in increased shear force value and GSH-Px activity, as well as a decrease in drip loss, ether extract content, and MDA content of the breast muscle in broilers under CHS (p < 0.05). Furthermore, tributyrin supplementation up-regulated the mRNA expressions of Nrf2, NQO1, HO-1, SOD, and GSH-Px of the breast muscle in broilers exposed to CHS (p < 0.05). Based on these positive effects, the study delved deeper to investigate the impact of 0.16% tributyrin supplementation (HS + 0.16%T) on the cecum microbiota. The HS + 0.16%T treatment showed an increase in the relative abundance of Rikenellaceae_RC9_gut_group (p < 0.05) and a trend towards an increase in Lactobacillus (p = 0.096) compared to the HS treatment. The results indicate that supplementation successfully improved the growth performance and meat quality of Taihe silky fowls. Furthermore, tributyrin supplementation, particularly at levels of 0.16%, improved meat quality by enhancing muscle antioxidant capacity, which is believed to be associated with activation of the Nrf2 signaling pathway.

Effects of Different Photoperiods on Peripheral 5-Hydroxytryptamine Metabolism, Breast Muscle Glucose Metabolism, and Myopathies in Broilers.

Background: There is a close relationship between breast muscle glucose metabolism, peripheral 5-hydroxytryptamine (5-HT), and myopathies in animals. Here, this study aimed to investigate the effects of different photoperiods on peripheral 5-HT metabolism, white striping (WS), and wooden breast (WB) in broilers. Methods: A total of 216 healthy 5-day-old (d) Arbor Acres (AA) male broilers were randomly assigned to 12L:12D, 18L:6D, and 24L:0D photoperiods for 4 weeks. Results: Compared with the 12L:12D photoperiod, we found the WB score in broilers was significantly increased in the 18L:6D and 24L:0D photoperiod at week 4 (p < 0.05). Muscle glycogen was significantly reduced (p < 0.05) and glycolysis was promoted in the breast muscles of broilers under the 18L:6D and 24L:0D photoperiods at week 2 and 4. Peripheral 5-HT concentrations, the mRNA expression of tryptophan hydroxylase 1 (TPH1) and serotonin transporter (SERT) in the cecal mucosa, and 5-hydroxytryptamine receptor 2A (5-HTR2A) mRNA expression in the breast muscle of broilers significantly up-regulated in the 18L:6D and 24L:0D photoperiod at week 2 and 4 (p < 0.05). Conclusions: Our findings revealed that extending the photoperiod improved the breast muscle growth rate, but up-regulated 5-HT synthesis and secretion to higher peripheral 5-HT, induced breast muscle glucose metabolism disorder, and increased WB incidence rates in broilers.

Effects of chronic heat stress on Ca2+ homeostasis, apoptosis, and protein carbonylation profiles in the breast muscle of broilers

Heat stress (HS) largely impairs the quality of broiler breast meat through protein oxidative modification. This study aimed to investigate the carbonylation pattern of Ca2+ channels and apoptotic proteins in the breast muscle of heat-stressed broilers. A total of 144 twenty-eight-day-old male Arbor Acres broilers were randomly divided into three treatment groups. The normal control (NC) group was kept at 22°C and provided with unlimited feed. The HS group was exposed to 32°C and provided with unlimited feed. The pair-fed (PF) group was kept at 22°C and given an amount of feed equivalent to that consumed by the HS group on the previous day. Results showed that broilers under HS conditions had a higher respiratory rate than those in NC and PF groups (P < 0.05). HS disrupted the morphology and structure of breast muscle fibers by decreasing the average diameters and average density of myofibers compared to the NC group (P < 0.05). HS increased the mean fluorescence intensity of the positive carbonyl signal in breast muscle compared with the NC group (P < 0.05). Besides, the pectoral Ca2+ concentration in the sarcoplasmic reticulum, cytoplasm, and mitochondria was elevated by HS when compared with the NC group (P < 0.05). In comparison to the NC and PF groups, HS increased the apoptosis rate and caspase-3 activity in the breast muscle (P < 0.05). Furthermore, HS elevated the relative protein expressions of plasma membrane Ca2+-ATPase, Na+/Ca2+ exchanger 1, and sarco/endoplasmic reticulum calcium transport ATPase 1 compared to the NC group (P < 0.05). Higher relative protein expression of μ-calpain and lower relative protein expression of cytosolic cytochrome complex were found in the HS group than the NC group (P < 0.05). HS decreased the carbonylation levels of transient receptor potential canonical 1 and inositol 1,4,5-trisphosphate receptor compared to the NC group (P < 0.05). Additionally, the carbonylation levels of cleaved caspase-3 and precursor caspase-9 were increased and decreased, respectively, by HS treatment compared to the NC group (P < 0.05). In conclusion, HS damages the myofiber based on Ca2+ dyshomeostasis and apoptosis, which are potentially associated with protein carbonylation. These results shed new light on the possible mechanism behind the development of poor meat quality in broilers due to HS.

Influence of incubation temperature on embryonic Days 4–7 on gene expression, M. pectoralis and M. gastrocnemius microstructure, and tibia characteristics in Ross 308 Broilers

ABSTRACT The incubation temperature can influence chicken bone and muscle development, and breast and leg muscles may respond differently to changes therein. Ross 308 broiler eggs were incubated at 36.5°C, 37.5°C (control), 38.5°C and 39.0°C on embryonic days 4–7. M. pectoralis and M. gastrocnemius were sampled at hatching and 5 weeks post-hatching, and differences in gene expression, microstructure and energy metabolism were examined. Tibia strength was tested, and gait scoring was performed. Broiler performance was similar at slaughter age, but initial growth was slowed by the 36.5°C treatment. The 38.5°C treatment reduced the M. gastrocnemius weight and shifted the M. pectoralis/M. gastrocnemius ratio. All treatments reduced M. gastrocnemius glycogen content relative to the control. The expression of single myogenesis-related genes was altered in the M. pectoralis by 36.5°C. The results indicate that the incubation temperature influences broiler muscle energy metabolism, and that the temperature of 38.5°C hampers leg muscle development.

Effects of the pesticide carbendazim on broiler chicken health and carbendazim residue levels in broiler tissues.

Pesticide residues may enter the human body through the food chain when livestock and poultry consume pesticide-contaminated feed. Therefore, monitoring and limiting pesticide residues in animal feed and animal-origin foods is necessary. Carbendazim is one of the most frequently detected pesticides in food and feed and has various toxic effects on non-target animals. This study investigated the effects of varying concentrations of carbendazim contamination in feed on broiler chicken growth performance, serum biochemical indicators, histopathology, and carbendazim residues in broiler muscles and livers. The results demonstrated that contamination of 5-100mg/kg carbendazim in feed did not affect broiler growth performance or health. Carbendazim contamination in feed at 200-800mg/kg slightly reduced growth performance. Broiler kidneys showed minor histopathological alterations after 400mg/kg carbendazim exposure. Furthermore, when the carbendazim content in feed was less than 25mg/kg, the residual carbendazim in the muscles and livers of broilers did not exceed the maximum residue level set by the European Union and China. Based on the above findings, carbendazim residues in the feed of less than 25mg/kg can be considered safe for chicken products.

Effect of manganese amino acid complexes on growth performance, meat quality, breast muscle and bone development in broilers

ABSTRACT 1. This study was conducted to investigate the effects of dietary supplementation of manganese (Mn) amino acid complexes on growth performance, Mn deposition, meat quality, breast muscle and bone development of broilers. 2. A total of 504, one-day-old male Arbor Acres broilers were randomly divided into seven treatments; control diet (CON; basal diet, no extra Mn addition), manganese diet (MnN as Numine®-Mn; CON + 40, 80, 120 or 160 mg Mn/kg), manganese-S group (MnS; CON + 120 mg Mn/kg as MnSO4·H2O), manganese-A diet (MnA as Mn from hydrolysed feather meal; CON + 40 mg Mn/kg as MnA). 3. There were no significant differences for average daily gain (ADG) or feed intake (ADFI) among diets during the feed phases (p > 0.05). The FCR in the starter and over the whole period were quadratically affected by dietary MnN dosage and gave the lowest FCR at 80 mg/kg (p < 0.05). The Mn content of thigh muscle, jejunum, heart, pancreas, liver and tibia increased linearly with MnN addition (p < 0.05). 4. For meat quality, MnN significantly increased colour (a*), pH45 min and pH24 h, reduced shear force, drip loss and pressure loss of breast muscle (p < 0.05). 5. Moreover, MnN significantly upregulated MYOD expression at d 21 and SOD expression at d 42, decreased MuRF1 and Atrogin-1 mRNA level at d 42 in breast muscle. Transcriptome analysis revealed that the regulating effect of MnN on muscle development significantly enriched signalling pathways such as adhesion, ECM-receptor, MAPK, mTOR and AMPK. Furthermore, dietary MnN significantly affected tibia length and growth plate development (p < 0.05) and promoted growth plate chondrocytes by increasing SOX-9, Runx-2, Mef2c, TGF-β, Ihh, Bcl-2 and Beclin1 and decreasing Bax and Caspase-3 (p < 0.05) expression which affect longitudinal tibial development. 6. In conclusion, Mn amino acid complexes could improve growth performance, tissue Mn deposition, breast muscle development, meat quality and bone development.

Effects of sodium lactate injection on meat quality and lactate content in broiler chickens: emphasis on injection method and dosage

This study aims to develop an experimental model of high lactate levels in broilers to mimic the condition of birds under stress or diseases and evaluate its consequent effects on meat quality. The injection sites and dosage effects were compared separately in 2 experiments. Experiment 1 includes 3 injection sites: intraperitoneal injection, intramuscular injection, and subcutaneous injection. Experiment 2 was a dosage experiment based on the results of Experiment 1: sodium lactate intraperitoneal injection group with 1.5, 3, 6 mM concentration. The results showed that injecting sodium lactate intraperitoneally, intramuscularly, or subcutaneously all significantly decreased body weight and breast muscle weight while elevating lactic acid levels in both the blood and breast muscle of broilers. Moreover, all 3 injection methods caused a significant reduction in pH24h and an increase in the shear force value of breast muscle. In addition, dose-response experiments of intraperitoneal injection showed that a concentration of 3 mM and 6 mM were significantly decreased body weight and breast muscle weight in broiler chickens, accompanied by a notable increase in breast muscle lactate content. Compared to the control group, intraperitoneal injections of 1.5 mM, 3 mM, and 6 mM sodium lactate treatments significantly reduced the yellowness values of the breast muscle. As the dose of sodium lactate increased, the shear force value of the breast meat exhibited linear and quadratic increments, while the drip loss decreased linearly. Intraperitoneal injection of 3 mM sodium lactate also significantly reduced the pH24h of broiler breast muscle. In addition, an increased dose of lactate injections up-regulated the glycolytic pathway responsible for endogenous lactate production in the breast muscle by upregulating the expression of phosphofructokinase, pyruvate kinase and lactate dehydrogenase A. In conclusion, intraperitoneal injection of sodium lactate at 3 mM directly increased breast muscle lactate levels, providing a valuable method for establishing a high-level lactate model in poultry.

Nano-Se exhibits limited protective effect against heat stress induced poor breast muscle meat quality of broilers compared with other selenium sources

BackgroundAt present, heat stress (HS) has become a key factor that impairs broiler breeding industry, which causes growth restriction and poor meat quality of broilers. Selenium (Se) is an excellent antioxidant and plays a unique role in meat quality improvement. Recent years, nano-selenium (NanoSe) has received tremendous attention in livestock production, due to its characteristic and good antibacterial performance in vitro. Here, we developed the heat stressed-broiler model to investigate the protective effects of NanoSe on growth performance and meat quality of broilers and compare whether there are differences with that of other Se sources (Sodium selenite, SS; Selenoyeast, SeY; Selenomethionine, SeMet).ResultsHS jeopardized the growth performance and caused poor meat quality of breast muscle in broilers, which were accompanied by lowered antioxidant capacity, increased glycolysis, increased anaerobic metabolism of pyruvate, mitochondrial stress and abnormal mitochondrial tricarboxylic acid (TCA) cycle. All Se sources supplementation exhibited protective effects, which increased the Se concentration and promoted the expression of selenoproteins, improved the mitochondrial homeostasis and the antioxidant capacity, and promoted the TCA cycle and the aerobic metabolism of pyruvate, thus improved the breast muscle meat quality of broilers exposed to HS. However, unlike the other three Se sources, the protective effect of NanoSe on meat quality of heat stressed-broilers was not ideal, which exhibited limited impact on the pH value, drip loss and cooking loss of the breast muscle. Compared with the other Se sources, broilers received NanoSe showed the lowest levels of slow MyHC, the highest levels of fast MyHC and glycogen, the highest mRNA levels of glycolysis-related genes (PFKM and PKM), the highest protein expression of HSP60 and CLPP, and the lowest enzyme activities of GSH-Px, citroyl synthetase (CS) and isocitrate dehydrogenase (ICD) in breast muscle. Consistent with the SS, the Se deposition in breast muscle of broilers received NanoSe was lower than that of broilers received SeY or SeMet. Besides, the regulatory efficiency of NanoSe on the expression of key selenoproteins (such as SELENOS) in breast muscle of heat stressed-broilers was also worse than that of other Se sources.ConclusionThrough comparing the meat quality, Se deposition, muscle fiber type conversion, glycolysis, mitochondrial homeostasis, and mitochondrial TCA cycle-related indicators of breast muscle in heat stressed broilers, we found that the protective effects of organic Se (SeY and SeMet) are better than that of inorganic Se (SS) and NanoSe. As a new Se source, though NanoSe showed some protective effect on breast muscle meat quality of heat stressed broilers, the protective effect of NanoSe is not ideal, compared with other Se sources.

Comparative effects of various dietary selenium sources on growth performance, meat quality, essential trace elements content, and antioxidant capacity in broilers

This study aimed to compare the effects of various dietary selenium (Se) sources (0.5 mg/kg) on performance, meat quality, and antioxidant capacity in broilers as well as essential trace elements concentrations in their blood and tissues. A total of 360 one-day-old male yellow-feathered chickens (37.00 ± 0.17 g) were randomly allocated to 5 diet treatments: the basal diet (CON) and 4 diets supplemented with sodium selenite (SS), selenomethionine (SM), selenium-enriched yeast (SY), and nano-selenium (NS) for 56 d, respectively, with 6 replicates per treatment and 12 chickens per replicate. Dietary Se supplementation did not affect growth performance and carcass characteristics in broilers (P > 0.05). Supplemental SM enhanced the redness in the pectoral muscle compared to CON and NS (P < 0.05). Supplementation of SY and NS improved the concentrations of Se, copper, manganese, and zinc in the serum (P < 0.05). Supplemental SS also elevated the zinc content in the serum (P < 0.05). Broilers fed the SY diet showed increased Se content in the liver and pectoral muscle compared to those fed CON, SM, and NS diets (P < 0.05). Also, SY improved the pectoral muscle Se concentration compared to SS (P < 0.05). Besides, dietary Se supplementation increased the Se content in the thigh muscle (P < 0.05), with SY showing highest Se deposition. Dietary supplementation with SS, SM, and NS improved the activities of total superoxide dismutase and total antioxidant capacity (T-AOC) in the serum (P < 0.05). Supplemental SY also elevated the T-AOC in the serum (P < 0.05). Additionally, SS and SM enhanced the T-AOC in the liver (P < 0.05). In conclusion, supplemental SM affected meat color. Supplementing diets with various Se sources increased antioxidant capacity and Se content in the thigh muscle of broilers, with SY showing a more pronounced deposition efficiency. Besides, diets supplemented with different Se sources had variable effects on the concentrations of essential trace elements in the serum and tissues of broilers.

Embryo thermal manipulation enhances mitochondrial function in the skeletal muscle of heat-stressed broilers by regulating transient receptor potential V2 expression

Heat stress induces mitochondrial dysfunction, thereby impeding skeletal muscle development and significantly impacting the economic efficiency of poultry production. This study aimed to investigate the effects of embryo thermal manipulation (TM, 41.5°C, 65% RH, 3 h/d during 16-18th embryonic age) on the mitochondrial function of the pectoralis major (PM) in broiler chickens exposed to thermoneutral (24 ± 1°C, 60% RH) or cyclic heat stress (35 ± 1°C, 60% RH, 12 h/d) from day 22 to 28, and to explore potential mechanisms involving transient receptor potential V2 (TRPV2). Additionally, in vitro experiments were conducted to assess the regulatory effects of TRPV2 pharmacological activation and inhibition on mitochondrial function in primary myotubes. The results revealed that TM had no discernible effect on the body weight and feed intake of broiler chickens under heat stress conditions (P > 0.05). However, it did delay the increase in rectal temperature and accelerate the decrease in serum T3 levels (P < 0.05). Furthermore, TM promoted the development of PM muscle fibers, significantly increasing myofiber diameter and cross-sectional area (P < 0.05). Under heat stress conditions, TM significantly upregulated the expression of mitochondrial electron transport chain (ETC) genes and TRPV2 in broiler PM muscle (P < 0.05), with a clear positive correlation observed between the two (P < 0.05). In vitro, pharmacological activation of TRPV2 not only increased its own expression but also enhanced mitochondrial ETC genes expression and oxidative phosphorylation function by upregulating intracellular calcium ion levels (P < 0.05). Conversely, TRPV2 inhibition had the opposite effect. Overall, this study underscores the potential of prenatal thermal manipulation in regulating postnatal broiler skeletal muscle development and mitochondrial function through the modulation of TRPV2 expression.

Effects of thyroid hormone on monochromatic light combinations mediate skeletal muscle fiber pattern in broilers

It has been shown that monochromatic green light and blue light promote skeletal muscle development in early (P0-P26) and later growth stages (P27-P42), respectively. This study further investigated the effects of monochromatic light combinations on myogenesis and myofiber types transformation in broilers. Here, a total of 252 chicks were exposed to monochromatic light [red (R), green (G), blue (B), or white light (W)], and monochromatic light combination [green and blue light combination (GB), blue and green light combination (BG), red and blue combination (RB)] until P42. Compared with other groups, GB significantly increased body weight, and muscle organ index, both proportions of larger-size myofibers and oxidative myofibers in the pectoralis major (PM) and gastrocnemius muscle (GAS). Meanwhile, GB up-regulated the abundance of oxidative genes MYH7B and MYH1B, transcription factors PAX7 and Myf5, antioxidant proteins Nrf2, HO-1, and GPX4, and the activities of antioxidant enzymes CAT, GPx, and T-AOC, but down-regulated the abundance of glycolytic related genes MYH 1A, MyoD, MyoG, Mstn, Keap1, TNFa, and MDA levels. Consistent with the change of myofiber pattern, GB significantly reduced serum thyroid hormone (TH) levels, up-regulated skeletal muscle deiodinase DIO3 expression and down-regulated deiodinase DIO2 expression, which may directly lead to the reduction of intramuscular TH levels to affect myofiber types transformation. In contrast, the proportion of fast glycolytic muscle fibers increased in the RR with increasing TH levels. After thyroidectomy, the above parameters were inversed and resulted in no significant difference of each color light treatment group. These data suggested that GB significantly increased the proportion of oxidative muscle fibers and antioxidant capacity in skeletal muscle of broilers, which was regulated by TH-DIO2/DIO3 signaling pathway.

Effect of dietary supplementation with sanguinarine on meat quality and lipid metabolism of broilers

Dietary Macleaya cordata extract (MCE) can improve the meat quality of poultry. However, the specific mechanism by which MCE regulates the meat quality has not been clarified yet. Sanguinarine (SAN) is one of the important natural active components in MCE. Our study aims to explore the regulatory mechanism of dietary SAN supplementation on meat quality through transcriptomic and gut microbiome analysis, thereby providing a basis for regularing meat quality with MCE. 240 1-day-old broilers were divided into 4 groups according to different doses of SAN (0, 0.225, 0.75, and 2.25 mg/kg). The results indicated that SAN significantly improve the physicochemical quality indicators of breast and thigh muscle in broilers, improved the serum biochemical indexes. Through transcriptome sequencing analysis of the liver and ileum tissues of broilers, we found that the differentially expressed genes induced by SAN were mainly enriched in lipid metabolism, which were related to the peroxisome proliferator-activated receptor (PPAR) pathway. It reconfirmed that SAN can regulate lipid metabolism in the body by promoting the expression of genes related to cholesterol metabolism, fatty acid transport and oxidation by RT-PCR, this ultimately affects the physicochemical quality of muscle. Additionally, through 16S rRNA sequencing analysis, we found that dietary addition of SAN increased the relative abundance of Bacteroides, Lactobacillus and unclassified_f_Lachnospiraceae, while decreased the relative abundance of Alistipes in ceca. To further investigate the impact of gut microbiota on lipid metabolism, we conducted a correlation analysis of PPAR pathway factor expression in cecum tissue and microflora structure. The results showed that Bacteroides exhibited a positive correlation with the expression of most genes in the PPAR signaling pathway. Unclassified_f__Lachnospiraceae is positively correlated with PPARγ, Cytochrome P450 family 7 subfamily A member 1 (CYP7A1) and Acyl-CoA synthetase long-chain family member 5 (ACSL5). In conclusion, dietary addition of SAN can promote the genes expression of the PPAR pathway, target the regulation of intestinal microflora structure and abundance and regulate lipid metabolism, thereby improving meat quality of broilers.

Effects of Cyclic-Chronic Heat Stress on Contractility-Related Genes in the Heart Muscle of Broilers based on RNA-Seq

Effects of Cyclic-Chronic Heat Stress on Contractility-Related Genes in the Heart Muscle of Broilers based on RNA-Seq

Association analysis of transcriptome and quasi-targeted metabolomics reveals the regulation mechanism underlying broiler muscle tissue development at different levels of dietary guanidinoacetic acid.

The development and characteristics of muscle fibers in broilers are critical determinants that influence their growth performance, as well as serve as essential prerequisites for the production of high-quality chicken meat. Guanidinoacetic acid (GAA) is a crucial endogenous substance in animal creatine synthesis, and its utilization as a feed additive has been demonstrated the capabilities to enhance animal performance, optimize muscle yield, and augment carcass quality. The objective of this study was to investigate the regulation and molecular mechanism underlying muscle development in broilers at different levels of GAA via multiple omics analysis. The 90 Cobb broilers, aged 1 day, were randomly allocated into three treatments consisting of five replicates of six chickens each. The control group was provided with a basal diet, while the Normal GAA and High GAA groups received a basal diet supplemented with 1.2 g/kg and 3.6 g/kg of GAA, respectively. After a feeding period of 42 days, the pectoralis muscles were collected for histomorphological observation, transcriptome and metabolomic analysis. The results demonstrated that the addition of 1.2 g/kg GAA in the diet led to an augmentation in muscle fiber diameter and up-regulation of IGF1, IHH, ASB2, and ANKRD2 gene expression. However, a high dose of 3.6 g/kg GAA in the diet potentially reversed the beneficial effects on chicken breast development by excessively activating the TGF-β signaling pathway and reducing nucleotide metabolite content. These findings would provide a theoretical foundation for enhancing the performance and meat quality of broilers by incorporating GAA as a feed additive.

Analysis of microRNA Expression Profiles in Broiler Muscle Tissues by Feeding Different Levels of Guanidinoacetic Acid.

The aim of this study was to explore the molecular mechanisms through which different levels of GAA affect chicken muscle development by influencing miRNA expression, to lay a theoretical foundation for the identification of key functional small RNAs related to poultry muscle development, and to provide new insights into the regulatory mechanisms of GAA on muscle development and meat quality in broilers. It provides a new theoretical basis for using GAA as a feed additive to improve feed performance. Small RNA sequencing technology was utilized to obtain the expression profiles of miRNA in the broiler pectoral muscle fed with different levels of GAA (0 g/kg, 1.2 g/kg and 3.6 g/kg). An analysis of differentially expressed miRNAs revealed 90 such miRNAs in the three combination comparisons, with gga-miR-130b-5p exhibiting significant differences across all three combinations. Furthermore, three of the differentially expressed miRNAs were performed by RT-qPCR verification, yielding results consistent with those obtained from small RNA sequencing. Target gene prediction, as well as the GO and KEGG enrichment analysis of differentially expressed miRNAs, indicated their involvement in muscle cell differentiation and other processes, particularly those associated with the MAPK signaling pathway. This study has, thus, provided valuable insights and resources for the further exploration of the miRNA molecular mechanism underlying the influence of guanidine acetic acid on broiler muscle development. Combined with previous studies and small RNA sequencing, adding 1.2 g/kg GAA to the diet can better promote the muscle development of broilers.

Dietary Chitosan Oligosaccharide Supplementation Improves Meat Quality by Improving Antioxidant Capacity and Fiber Characteristics in the Thigh Muscle of Broilers.

This study investigated the effects of dietary chitosan oligosaccharide (COS) supplementation on meat quality, antioxidant capacity, and muscle fiber characteristics in the thigh muscle of broilers. The results showed that dietary COS supplementation decreased shear force and increased crude protein content and nutritional value in the thigh muscle, while decreasing the content of C16:0, C18:0, and total saturated fatty acids. Dietary COS supplementation increased free radical scavenging activity, antioxidant enzyme activity, and antioxidant enzyme-related gene expression. Additionally, COS promoted MyHCI while decreasing MyHCIIb mRNA expression levels. The myofiber transformation was associated with upregulated gene expression of CaN, NFATc1, MyoD, and SIRT1. Together, the results of this study demonstrate that dietary COS supplementation improves meat quality, nutritional value, antioxidant capacity, and myofiber transformation to more oxidative muscle fibers in the thigh muscle of broilers when its supplemental level is 400 mg/kg.

Improvement of Antioxidative Activity of Broiler Muscles after Dietary Modulation with Selenium and Methionine

Abstract The objective of the study was to compare the antioxidative capacity of broiler chicken breast and leg muscles after dietary modulation with selenium (Se) and methionine (Met). Free radical scavenging (ABTS, DPPH) and iron reduction (FRAP) activities were determined as the total antioxidative potential (TEAC), as well the enzyme activity of catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (GPx), in relation to concentrations of lipid peroxidation end products (TBARS). Analyses were performed on breast m. pectoralis superficialis and profundus individually and together. The studied leg muscles included biceps femoris, gastrocnemicus, iliotiobialis, peroneus longus, sartorius, semimembranosus, semitendinosus and all leg muscles together. Flex broiler chickens were fed diets supplemented with 6.7, 8.2, 9.7 and 11.2 g DL-methionine/kg feed and Se as sodium selenite and selenized yeast at 0.26, 0.38 and 0.50 mg Se/kg. Greater TEAC and enzyme activities were observed in leg than in breast muscles. Selenium did not change TEAC in muscles sets, but improved antiradical capacity in the pectoralis major and minor, sartorius and biceps femoris. The highest level of methionine increased TEAC in individual leg muscles. Selenium and methionine at the highest concentrations increased SOD activity in the entire group and individual muscles, while Se raised GPx activity. In conclusion, the diet supplementation with selenium and high concentrations of methionine had a greater impact on the antioxidative potential of individual than the whole set of chicken breast and leg muscles. The positive effect of the studied diet modulation could raise the quality and extend the shelf-life of fresh chicken meat.

Metabolomic analysis reveals biogenic selenium nanoparticles improve the meat quality of thigh muscle in heat-stressed broilers is related to the regulation of ferroptosis pathway

Heat stress (HS) causes oxidative damage and abnormal metabolism of muscle, thus impairing the meat quality in broilers. Selenium is an indispensable element for enhancing antioxidant systems. In our previous study, we synthesized a novel type of biogenic selenium nanoparticles synthesized with alginate oligosaccharides (SeNPs-AOS), and found that the particle size of Se is 80 nm and the Se content is 8% in the SeNPs-AOS; and dietary 5 mg/kg SeNPs-AOS has been shown to be effective against HS in broilers. However, whether SeNPs-AOS can mitigate HS-induced the impairment of thigh muscle quality in broilers is still unclear. Therefore, the purpose of this study was to investigate the protective effects of dietary SeNPs-AOS on meat quality, antioxidant capacity, and metabolomics of thigh muscle in broilers under HS. A total of 192 twenty-one-day-old Arbor Acres broilers were randomly divided into 4 groups with 6 replicates per group (8 broilers per replicate) according to a 2 × 2 experimental design: thermoneutral group (TN, broilers raised under 23±1.5°C); TN+SeNPs-AOS group (TN group supplemented 5 mg/kg SeNPS-AOS); HS group (broilers raised under 33 ± 2°C for 10 h/d); and HS + SeNPs-AOS group (HS group supplemented 5 mg/kg SeNPS-AOS). The results showed that HS increased the freezing loss, cooking loss, and malondialdehyde (MDA) content of thigh muscle, whereas decreased the total superoxide dismutase (T-SOD), glutathione peroxidase (GSH-Px), and catalase (CAT) activities, as well as downregulated the mRNA expression of SOD2, CAT, GPX3, nuclear factor erythroid 2-related factor 2 (Nrf2), selenoprotein S (SELENOS), solute carrier family 7 member 11 (SLC7A11), GPX4, and ferroportin 1 (Fpn1) of thigh muscle (P < 0.05). Dietary SeNPS-AOS reduced the b* value, elevated the pH0min value and the activities of T-SOD, GSH-Px, glutathione S-transferase (GST) and the mRNA expression levels of GSTT1, GSTA3, GPX1, GPX3, ferritin heavy polypeptide-1 (FTH1), and Fpn1 of thigh muscle in broilers under HS (P < 0.05). Nontargeted metabolomics analysis identified a total of 79 metabolites with significant differences among the four groups, and the differential metabolites were mainly enriched in 8 metabolic pathways including glutathione metabolism and ferroptosis (P < 0.05). In summary, dietary 5 mg/kg SeNPs-AOS (Se content of 8%) could alleviate HS-induced impairment of meat quality by improving the oxidative damage, metabolic disorders and ferroptosis of thigh muscle in broilers challenged with HS. Suggesting that the SeNPs-AOS may be used as a novel nano-modifier for meat quality in broilers raised in thermal environment.

The occurrence of myopathies and meat abnormalities in modern broiler farming

Over the past few decades, there has been a significant increase in the production and consumption of poultry meat due to its high-quality nutritional profile, relatively low production costs, and ease of meat processing. This growing demand has led to progressive improvements in genetic selection for fast-growing broilers, triggering several spontaneous idiopathic muscle abnormalities along with an increased susceptibility to stress-induced myopathy. These muscle abnormalities have a negative impact on the quality of both fresh and processed chicken meat, primarily affecting the large breast muscle (m. pectoralis major) of broilers, which is also the most valuable part of the carcass. Frequent meat abnormalities include the occurrence of pale, soft, and exudative meat, primarily characterized by reduced water-holding capacity, while Deep Pectoral Myopathy results in a change in colour and a significant reduction in the attractive appearance of the small breast muscle (m. pectoralis minor). Myopathies labelled as "White Striping" are characterized by superficial white stripes, "Wooden Breast" is marked by pale and bulging areas of significant hardness, while "Spaghetti Meat" is described by the separation of muscle fibres resembling spaghetti pasta. These mentioned abnormalities and myopathies negatively impact the economic aspect of the poultry industry during the removal of affected parts and, furthermore, reduce the qualitative and nutritional value of the meat, posing challenges during technological processes. This paper describes recent findings on the occurrence, characteristics, and prevalence of the most common myopathies affecting modern broiler farming.