Breast Muscle Research Articles

Changes in gene expression in the intestinal mucus of broilers with woody breast myopathy

Previous work has shown that dietary treatments affect woody breast (WB) incidence differently, which indicates that gut conditions such as gut barrier function, inflammation, and oxidative stress are likely related to WB. In this study, dietary supplementation with antibiotics (bacitracin) or probiotics (Bacillus subtilis) was investigated for their effects on the expression of transcripts related to gut barrier function, inflammation, and oxidative stress in the mucus lining of the jejunum from broilers with or without WB. A split-plot experimental design was used in this study. The dietary treatments served as the main plot factor and the breast muscle condition was the subplot factor. On d 41, jejunum mucus was collected from 1 bird from each of 3 replicate pens in each 3 dietary treatment groups that exhibited WB and an additional bird that contained a normal breast (3 biological replicates/treatment/phenotype; 3 × 3 × 2, total N = 18). Total RNA was extracted using a commercial RNA extraction kit. The expression levels of CLDN1, MUC6, TLR2A, TLR2B, TLR4, IFN-γ, IL-1β, IL-8L1, IL-10, NOS2, and SOD were determined using 2-step RT-qPCR analysis. The gene expression difference in ΔCt values was determined after normalizing with the chicken 18S rRNA gene. When the significant differences occurred between treatments, the relative fold change was calculated using the ΔΔCt method and the significance level was calculated. The PROC GLM procedure of SAS 9.4 was used, and the level of significance was set at P ≤ 0.05. There were no significant interactive effects between diet and the breast muscle condition on the expression of any of the genes tested. However, birds with WB exhibited higher MUC6 (P < 0.0001) gene expression levels than birds with normal breast muscles. In addition, the expression of SOD decreased in birds that were fed the antibiotic diet when compared to birds that were fed the probiotic diet (P = 0.014). In conclusion, WB identified in broilers tested in the current study is attributed to increased expression of mucin, indicating a correlation between WB incidence and gel-forming mucin secretion and pathogen signaling.

Influence of Genotype on Meat Quality in Laying Hens after the Egg Production Season

The aim of this study was to compare the quality characteristics of the meat of two genotypes (Lohmann Brown and Lohmann White) of laying hens after the laying period. Studies were conducted on pectoral and leg muscles from 26 females, 13 of each genotype. Breast and leg muscles were evaluated in terms of their basic chemical composition, acidity (pH24), color attributes (L*, a*, b*), electrical conductivity (EC24) and macro- (K, P, Na, Mg, Ca) and microelements (Fe, Zn, Cu, Mn, Cr). Analysis of the texture of the pectoral muscle major and rheological properties (sum of viscosity modules and sum of elasticity modules) was also performed. Breast and leg meat were also subjected to sensory evaluation. The genotype of the birds significantly affected the percentage of intramuscular fat in the pectoral muscle and the percentage of protein, fat and water in the leg muscle. When analyzing pectoral and leg muscles for color attributes, we found no significant (p &gt; 0.05) differences between genotypes. Differences were shown, however, between genotypes in EC24 and phosphorus content in leg muscle. Breast muscles differed significantly (p &lt; 0.05) in iron and zinc content. Sensory analysis revealed significant differences between genotypes in leg muscle tenderness and juiciness, and breast muscle juiciness and aroma desirability. When analyzing the breast muscle in terms of texture, we did not observe any significant differences, nor did we find any differences in the assessment of rheological properties. Not depending on genotype, however, we noted significant differences between protein, fat, water and collagen content, sodium, magnesium, calcium, iron, zinc, copper, manganese, chromium, acidity, color parameters (L*, a*, b*), EC24 and tastiness desirability between breast meat and leg meat. The results of this study showed that meat from old hens obtained after the laying period is a good material for further technological processing, due to its favorable basic chemical composition and high nutritional value expressed in the content of macro- and microelements, and is also characterized by relatively good sensory characteristics, which can be improved by marinating or adding enzymatic preparations during its processing.

Gut microbiota intervention attenuates thermogenesis in broilers exposed to high temperature through modulation of the hypothalamic 5-HT pathway

BackgroundBroilers have a robust metabolism and high body temperature, which make them less tolerant to high-temperature (HT) environments and more susceptible to challenges from elevated temperatures. Gut microbes, functioning as symbionts within the host, possess the capacity to significantly regulate the physiological functions and environmental adaptability of the host. This study aims to investigate the effects of gut microbial intervention on the body temperature and thermogenesis of broilers at different ambient temperatures, as well as the underlying mechanism involving the "gut-brain" axis.MethodsBroilers were subjected to gut microbiota interference with or without antibiotics (control or ABX) starting at 1 day of age. At 21 day of age, they were divided into 4 groups and exposed to different environments for 7 d: The control and ABX groups at room temperature (RT, 24 ± 1 °C, 60% relative humidity (RH), 24 h/d) and the control-HT and ABX-HT groups at high temperature (HT, 32 ± 1 °C, 60% RH, 24 h/d).Results The results demonstrated that the antibiotic-induced gut microbiota intervention increased body weight and improved feed conversion in broiler chickens (P < 0.05). Under HT conditions, the microbiota intervention reduced the rectal temperature of broiler chickens (P < 0.05), inhibited the expression of avUCP and thermogenesis-related genes in breast muscle and liver (P < 0.05), and thus decreased thermogenesis capacity. Furthermore, the gut microbiota intervention blunted the hypothalamic‒pituitary‒adrenal axis and hypothalamic–pituitary–thyroid axis activation induced by HT conditions. By analyzing the cecal microbiota composition of control and ABX chickens maintained under HT conditions, we found that Alistipes was enriched in control chickens. In contrast, antibiotic-induced gut microbiota intervention resulted in a decrease in the relative abundance of Alistipes (P < 0.05). Moreover, this difference was accompanied by increased hypothalamic 5-hydroxytryptamine (5-HT) content and TPH2 expression (P < 0.05).ConclusionsThese findings underscore the critical role of the gut microbiota in regulating broiler thermogenesis via the gut-brain axis and suggest that the hypothalamic 5-HT pathway may be a potential mechanism by which the gut microbiota affects thermoregulation in broilers.Graphical

The fatty acid profile and the quality of breast and leg muscles in female and male pearl gray guinea fowl (Numida meleagris)

The aim of this study was to evaluate the fatty acid (FA) profile and the quality of breast and leg muscles in male and female guinea fowl. In comparison with leg muscles, breast muscles had a higher content of dry matter and total protein, and contained less fat and total collagen (P ≤ 0.05). Sex had no effect on the chemical composition of the studied muscles or the FA profile of intramuscular fat (IMF) (P > 0.05). The IMF of breast muscles was characterized by higher proportions of total saturated fatty acids (SFAs) and polyunsaturated fatty acids (PUFAs), and lower proportions of total unsaturated fatty acids (UFAs) and monounsaturated fatty acids (MUFAs) (P ≤ 0.05) than the IMF of leg muscles. The physicochemical properties of guinea fowl meat were significantly influenced by muscle type (P ≤ 0.05), but not by sex (P > 0.05). Leg muscles were characterized by a higher pH, higher cooking loss, lower lightness (L*), lower drip loss, a higher contribution of redness (a*), and a lower contribution of yellowness (b*) than breast muscles (P ≤ 0.05). The experimental factors had no effect on the sensory attributes or the shear force values of the analyzed muscles (P > 0.05). The unique sensory attributes, high protein content, and low fat content of the analyzed muscles indicate that guinea fowl meat can be a dietary supplement and an addition to other types of meat consumed, especially that most guinea fowl are reared in extensive farming systems that contribute to sustainable food production.

Functional identification of PGM1 in the regulating development and depositing of inosine monophosphate specific for myoblasts.

Inosine monophosphate (IMP) is naturally present in poultry muscle and plays a key role in improving meat flavour. However, IMP deposition is regulated by numerous genes and complex molecular networks. In order to excavate key candidate genes that may regulate IMP synthesis, we performed proteome and metabolome analyses on the leg muscle, compared to the breast muscle control of 180-day-old Jingyuan chickens (hens), which had different IMP content. The key candidate genes identified by a differential analysis were verified to be associated with regulation of IMP-specific deposition. The results showed that the differentially expressed (DE) proteins and metabolites jointly involve 14 metabolic pathways, among which the purine metabolic pathway closely related to IMP synthesis and metabolism is enriched with four DE proteins downregulated (with higher expression in breast muscles than in leg muscles), including adenylate kinase 1 (AK1), adenosine monophosphate deaminase 1 (AMPD1), pyruvate kinase muscle isoenzyme 2 (PKM2) and phosphoglucomutase 1 (PGM1), six DE metabolites, Hypoxanthine, Guanosine, L-Glutamine, AICAR, AMP and Adenylsuccinic acid. Analysis of PGM1 gene showed that the high expression of PGM1 promoted the proliferation and differentiation of myoblasts and inhibited the apoptosis of myoblasts. ELISA tests have shown that PGM1 reduced adenosine triphosphate (ATP) and IMP and uric acid (UA), while enhancing the biosynthesis of hypoxanthine (HX). In addition, up-regulation of PGM1 inhibited the expression of purine metabolism pathway related genes, and promoted the IMP de novo and salvage synthesis pathways. This study preliminarily explored the mechanism of action of PGM1 in regulating the growth and development of myoblasts and specific IMP deposition in Jingyuan chickens, which provided certain theoretical basis for the development and utilization of excellent traits in Jingyuan chickens.

Metabolomics analysis to interpret changes in physiological and metabolic responses to chronic heat stress in Pekin ducks

Heat stress (HS) is a major environmental threat that affects duck production in subtropical and tropical regions, especially in summer. This study aimed to evaluate the physiological and metabolic responses of Pekin ducks to chronic HS conditions via liquid chromatography-mass spectrometry (LC-MS) using a paired-fed (PF) experimental design. On the basis of equivalent feed intake (HS vs. PF), HS significantly reduced growth performance and the percentage of leg and breast muscles, however, markedly increased the percentage of abdominal fat and breast skin fat. Serum metabolomics results revealed that heat-stressed ducks showed enhanced glycolysis and pentose phosphate pathways, as demonstrated by higher glucose 6-phosphate and 6-phogluconic acid levels in the PF vs. HS comparison. HS decreased hepatic mRNA levels of mitochondrial fatty acid β-oxidation-related genes (MCAD and SCAD) compared to the PF group, resulting in acetylcarnitine accumulation in serum. Moreover, HS elevated the concentrations of serum amino acids and mRNA levels of ubiquitination-related genes (MuRF1 and MAFbx) in the skeletal muscle and amino acid transporter-related genes (SLC1A1 and SLC7A1) and gluconeogenesis-related genes (PCK1 and PCase) in the liver compared to the PF group. When compared to the normal control group (NC), HS further decreased growth performance, but it elevated the abdominal fat rate. However, increased mRNA levels of ubiquitination-related genes and serum amino acid accumulation were not observed in the HS group compared to the NC group, implying that reduced feed intake masked the effect of HS on skeletal muscle breakdown and is a form of protection for the organism. These results suggest that chronic HS induces protein degradation in the skeletal muscle to provide amino acids for hepatic gluconeogenesis to provide sufficient energy, as Pekin ducks under HS conditions failed to efficiently oxidise fatty acids and ketones in the mitochondria, leading to poor growth performance and slaughter characteristics.

In-ovo feeding with creatine monohydrate: implications for chicken energy reserves and breast muscle development during the pre-post hatching period.

The most dynamic period throughout the lifespan of broiler chickens is the pre-post-hatching period, entailing profound effects on their energy status, survival rate, body weight, and muscle growth. Given the significance of this pivotal period, we evaluated the effect of in-ovo feeding (IOF) with creatine monohydrate on late-term embryos' and hatchlings' energy reserves and post-hatch breast muscle development. The results demonstrate that IOF with creatine elevates the levels of high-energy-value molecules (creatine and glycogen) in the liver, breast muscle and yolk sac tissues 48h post IOF, on embryonic day 19 (p < 0.03). Despite this evidence, using a novel automated image analysis tool on day 14 post-hatch, we found a significantly higher number of myofibers with lower diameter and area in the IOF creatine group compared to the control and IOF NaCl groups (p < 0.004). Gene expression analysis, at hatch, revealed that IOF creatine group had significantly higher expression levels of myogenin (MYOG) and insulin-like growth factor 1 (IGF1), related to differentiation of myogenic cells (p < 0.01), and lower expression of myogenic differentiation protein 1 (MyoD), related to their proliferation (p < 0.04). These results imply a possible effect of IOF with creatine on breast muscle development through differential expression of genes involved in myogenic proliferation and differentiation. The findings provide valuable insights into the potential of pre-hatch enrichment with creatine in modulating post-hatch muscle growth and development.

Integrated analysis of whole genome and transcriptome sequencing uncovers genetic differences between Zi goose and Xianghai flying goose.

Zi goose is a famous indigenous breed originating from northeast China with high annual egg production. Xianghai flying goose is a composite breed and is bred by crosses of the wild swan goose and the Zi goose. Our previous study revealed significant differences in muscle fiber characteristics between the two populations. Here, we aimed to reveal the underlying genetic basis of the above phenotype differences through whole-genome and transcriptome analysis. A total of 20 blood samples (10 Zi geese and 10 Xianghai flying geese) were used for whole genome sequencing, and eight breast muscle tissue samples (four Zi geese and four Xianghai flying geese) were used for RNA sequencing. Using the FST and XP-EHH analysis, some highly differentiated genome regions annotated with egg production (RORB, WNT4, BMPR1B) and breast muscle development (WNT7B) between the two populations were detected. RNA-sequencing analysis revealed differentially expressed genes related to muscle development (IGF1, PAX7). Moreover, several genes were detected by both genome and transcriptome analysis, and some of them were reported to be associated with muscle growth (SLIT2, PREX1) and intramuscular fat (COL6A1). These findings will help researchers better understand the genetic basis related to egg production and muscle development in geese.

Molecular genetic characterization and meat-use functional gene identification in Jianshui yellow-brown ducks through combined resequencing and transcriptome analysis.

The Jianshui yellow-brown duck is a unique country-specific waterfowl species in Yunnan Province, well known for its tender meat. However, there is a lack of comprehensive systematic research on the molecular genetic characteristics, especially germplasm resources and economic traits, of the Jianshui yellow-brown ducks. This study investigated the molecular genetic characteristics of Jianshui yellow-brown ducks, compared their selection signals with those of ancestral mallard and meat-type Pekin ducks, and identified genes specific to their meat-use performance. Furthermore, this study also evaluated the breeding potential for its meat performance. In this study, phylogenetic trees, PCA and Admixture analysis were used to investigate the population genetic structure among local duck breeds in China; population genetic differentiation index (Fst), nucleotide diversity and Tajima's D were used to detect selected loci and genes in the population of Jianshui yellow-brown ducks; and transcriptome technology was used to screen for differentially expressed genes in the liver, sebum and breast muscle tissues, and finally, the results of the genome selection signals and transcriptome data were integrated to excavate functional genes affecting the meat performance of the Jianshui yellow-brown ducks. The results of the genetic structure of the population showed that Jianshui yellow-brown ducks were clustered into a separate group. Selection signal analysis indicated significant selection pressure on certain genes related to meat characteristics (ELOVL2, ELOVL3, GDF10, VSTM2A, PHOSPHO1, and IGF2BP1) in both Jianshui yellow-brown ducks and mallards. Transcriptomic data analysis suggested that ELOVL3, PHOSPHO1, and GDF10 are vital candidate genes influencing meat production and quality in Jianshui yellow-brown ducks. A comparison of selection signals between Jianshui yellow-brown ducks and Pekin ducks revealed only 21 selected genes in the Jianshui yellow-brown duck population, and no significant genes were related to meat traits. Moreover, whole-genome resequencing data suggested that the Jianshui yellow-brown duck represents a unique category with distinct genetic mechanisms. Through selection signaling and transcriptomic approaches, we successfully screened and identified important candidate genes affecting meat traits in Jianshui yellow-brown ducks. Furthermore, the Jianshui yellow-brown duck has good potential for improved meat performance, highlighting the need for further improvement.

Comparison of growth performance, meat quality, and blood biochemical indexes of Yangzhou goose under different feeding patterns

The East China region is the main market for the breeding and consumption of meat geese in China, in order to provide data reference for small and medium-sized farms and farmers to choose breeding methods and growth performance. This study selected 300 Yangzhou geese as materials and determined the number of geese in each group according to different modes. The meat quality, blood biochemical indicators, and economic benefits of 4 common feeding methods (Group I: full concentrate feeding; Group II: concentrate feeding in the first stage + 3% fat addition in the later stage; Group III: concentrate feeding + pasture supplementation; Group IV: grazing feeding + concentrate) in East China were analyzed. The results are as follows: The average daily weight gain of Yangzhou geese in Group IV at 5 to 8 wk old was the highest, with the highest feed utilization rate. The body weight at 8 wk old was significantly higher than that of the group III (P < 0.05). The total mortality rate of Group I and II remained at a relatively low level, while the mortality rates of Group III and IV exceeded 17%. The SR, FECR, and FECW of female geese in Groups II, III, and IV were significantly higher than those in Control group I (P < 0.05). Different feeding methods have little effect on the quality of goose breast muscles, while in terms of leg muscles, Group II has the highest binding force, significantly higher than Group I (P < 0.05). The rate of chest muscle loss in group III was significantly higher than that in groups I and II (P < 0.05). However, the pH of leg muscles in groups I, II and III was significantly higher than that in group IV (P < 0.05). Group II has the highest protein and collagen content, and Group I has the highest fat content. Except for the significantly higher histidine content in Groups I And II compared to those in Groups III and IV (P < 0.05), there was almost no significant difference in amino acid content among the groups (P > 0.05). There was no significant difference in ALB/GLO content among the 3 groups of Groups II to IV, but they were all significantly higher than those of Group I (P < 0.05). There was no statistically significant difference in other indicators among the groups (P > 0.05). There was no significant difference in the content of Ca, Cu, Fe, P, Zn, and other elements in the muscles between the groups (P > 0.05). This study solved the problems of slow growth, poor meat performance, and low economic benefits in meat goose breeding, providing theoretical basis and data support for meat goose breeding enterprises and farmers to choose appropriate breeding modes.

Genomic insights into the contribution of de novo lipogenesis to intramuscular fat deposition in chicken

IntroductionThe proportion of animal based foods in daily diet of consumers is constantly increasing, with chicken being highly favored due to its high protein and low fat characteristics. The consumption of chicken around the world is steadily increasing. Intramuscular fat (IMF) is a key indicator affecting meat quality. ObjectHigh IMF content can contribute to improve the quality of chicken meat. The regulatory mechanism of IMF deposition in chicken is poorly understood, so its complete elucidation is essential to improve chicken meat quality. MethodHere, we performed whole genome resequencing on 516 yellow feather chickens and single-cell RNA sequencing on 3 63-day-old female JXY chickens. In addition, transcriptome sequencing techniques were also performed on breast muscle tissue of JXY chickens at different developmental stages. And 13C isotope tracing technique was applied. ResultsIn this study, a large-scale genetic analysis of an IMF-selected population and a control population identified fatty acid synthase (FASN) as a key gene for improving IMF content. Also, contrary to conventional view, de novo lipogenesis (DNL) was deemed to be an important contributor to IMF deposition. As expected, further analyses by isotope tracing and other techniques, confirmed that DNL mainly occurs in myocytes, contributing about 40% of the total fatty acids through the regulation of FASN, using the available FAs as substrates. Additionally, we also identified a relevant causal mutation in the FASN gene with effects on FA composition. ConclusionThese findings contribute to the understanding of fat metabolism in muscle tissue of poultry, and provide the feasible strategy for the production of high-quality chicken meat.

Dietary bile acids improve breast muscle growth in chickens through FXR/IGF2 pathway

It is a common practice to provide fast-growing broilers with high-fat diets in the context of integrated farms in Northeast China. Therefore, fat digestion, absorption, and utilization efficiency are critical for broiler meat production. Bile acids (BA) promote fat digestion and absorption, but whether and how BA affects muscle growth in broilers remains unclear. In this study, 1-day-old broilers were fed diets containing varying levels of crude fat (low, medium, and high) with or without BA supplementation for 42 d. Chickens fed a high-fat diet supplemented with BA exhibited significantly (P < 0.05) higher body weight (BW) at 21 d and average daily gain (ADG) during the first 21 d compared to the other groups. Throughout the entire experiment, feed conversion rate (FCR) was significantly (P < 0.05) lower in the high-fat group without the addition of BA, which was further decreased (P < 0.05) with BA supplementation. The improved growth performance in the BA-supplemented high-fat group was associated with significantly (P < 0.05) higher lipase activity in the small intestine chyme, a decreased trend (P = 0.06) in abdominal fat ratio, and significantly (P < 0.05) higher breast muscle mass. Histological analysis revealed significant (P < 0.05) increases in myofiber diameter, cross-sectional area, and RNA and DNA concentrations in the breast muscle of BA-supplemented broilers on the high-fat diet. Additional histological analysis further revealed significant (P < 0.05) enhancements in myofiber diameter, cross-sectional area, and RNA and DNA concentrations within the breast muscles of broilers supplemented with BA and a high-fat diet. The increased insulin-like growth factor 2 (IGF2) in the breast muscle of broilers fed a BA-supplemented high-fat diet correlated with significantly (P < 0.05) increased farnesoid X factor (FXR) protein expression and binding to the IGF2 promoter. These results suggest that dietary BA supplementation improves FCR and breast muscle growth in broilers fed a high-fat diet, potentially through the FXR-mediated IGF2 pathway.

Dietary supplementation broilers with β-alanine and garlic extract improves production results and muscle oxidative status

Abstract To improve the quality of poultry meat and increase the health-promoting properties, poultry nutrition used additives such as phytobiotic substances and amino acids. The aim of this study was to analyze the possibility of improving production rates and meat quality by simultaneously supplementing broiler diets with garlic extract and β-alanine. A total of 1050 ROSS 308 broiler chickens were part of the experiment. The chickens were divided into several groups: the control group without additives (Control), groups with 0.5% garlic extract (G05) or 2% garlic extract (G2), groups with 0.5% added β-alanine (B0.5) or 2% added β-alanine (B2), and groups with both 0.5% added garlic extract and 0.5% added β-alanine (BG0.5) or 2% garlic extract and 2% added β-alanine (BG2). Each group was further divided into six replicates, with each replicate consisting of 25 birds. After 35 days of rearing, the chickens were slaughtered, and analyses were conducted on breast and leg muscle chemistry, bioactive peptide content, and the oxidative status indicator dimalondialdehyde in muscles stored under refrigeration until day 10.The results showed significant improvements in certain aspects. The BG05 group exhibited an increase in final body weight (P&lt;0.001) and improved feed utilization (P&lt;0.001). The β-alanine-supplemented groups showed higher levels of protein (P&lt;0.001), carnosine (P&lt;0.001), and anserine (P&lt;0.001) in both breast and leg muscles. Additionally, leg muscles showed increased levels of protein (P&lt;0.001), carnosine (P&lt;0.001),and anserine (P&lt;0.001).Notably, the BG05 group contained lower levels of MDA in both breast and leg muscles (P&lt;0.001).

Assessment of Enrofloxacin Usage and Residue Levels of Enrofloxacin-Ciprofloxacin in Breast and Liver Tissues of Commercial Broilers Sold in Kampala-Uganda.

Human exposure to veterinary drugs like fluoroquinolones occurs due to the presence of their residues in foods from animal sources in varying concentrations. The existence of antibiotic residues in foodstuffs can pose great public health problems to consumers. This study aimed to assess enrofloxacin use patterns and assess residue levels of enrofloxacin/ciprofloxacin in breast muscle and liver tissues of broiler chickens sold for consumption in Kampala capital city. This was a cross-sectional study that involved both field survey and laboratory-based methods. The field study involved the use of qualitative and semi-quantitative data collection tools to interview 34 broiler farmers and 10 veterinary drugs vendors. For the determination of enrofloxacin/ciprofloxacin levels, 68 chicken breast and liver tissue samples were collected from main markets in Kampala over one month and analyzed using HPLC-UV. Enrofloxacin was the most used antibiotic (100%) for the management of poultry diseases, majorly respiratory diseases (100%), salmonella infections (40%), and disease prevention (60%). Over 76% of the farmers knew the meat withdrawal time (WDT) for enrofloxacin, but none of them adhered to this. Over 70% of the farmers reported that the veterinary drugs vendors were not providing meat WDT information. Enrofloxacin/ciprofloxacin residues were identified in 35.3% (12/34) of the muscle and 38.2% (13/34) of the liver tissues analyzed. Of those muscle and liver tissue samples that tested positive, 25% (3/12) and 38.5% (5/13) respectively had drug concentrations higher than the recommended Maximum Residue Limits. The overall mean enrofloxacin/ciprofloxacin concentration in the chicken muscle and liver tissues was 83.6 (±34.5) µg/kg and 171.5 (±75.9) µg/kg. This observed presence of enrofloxacin/ciprofloxacin levels above safety requirements is attributable to inadequate medicines use information provided by veterinary drugs vendors to farmers and also to the non-compliance of some farmers to meat WDT due to the economic implications.

Relationships between pH values and some physico-chemical and colour traits of quail breast meat

Abstract. The aim of this study was to establish variation ranges of breast meat рН24, water holding capacity (WHC), water absorption capacity (WAC), and colour (CIEL*a*b*) in domestic quails and to analyze the patterns of relationships between рН24 and muscle hydrophilic and colour characteristics in the studied dataset. The investigation summarizes the results of two research experiments performed on breast muscle (M. pectoralis) from 151 domestic quails. It was found that the studied dataset was relatively homogeneous (CV&lt;30%). The least dispersion was shown for рН24 and L* traits (CV of 3.8% and 8.3%, respectively). The analysis of results demonstrated that hydrophilic properties (WHC, WAC) and colour characteristics (L*, a* and b*) of M. pectoralis depended on рН24 values. With the exception of the association between рН24 and WAC, which was positive, all other correlations were negative. According to the present study, the correlation between рН24 and WHC was weak, and only 6.6% of breast muscle WHC depended on change in рН24 values. The breast meat WAC and colour characteristics were largely dependent on рН24, as more than 40% of their variation was determined by the tested factor.

Physiological, Haematological And Production Characteristics Of Pheasants In Different Rearing Conditions

Summary This paper presents a physiological, hematological, and biochemical study of the impact of different rearing conditions on pheasant production outcomes and mortality rates in both the pheasant parent flock and pheasant chicks up to 6 weeks old. Pheasant breeding holds significance within hunting activities and meat production for the food market due to its high biological and nutritive value. Pheasant meat contains high-quality proteins, minerals, essential unsaturated fatty acids, and boasts a low-fat percentage. The quality of pheasant meat derived from natural habitats holds a higher biological value compared to that of pheasants raised on farms, featuring higher water, protein, and calcium contents, and a lower fat percentage. The dry mass of breast muscles from farm-reared birds contains more protein and less fat when compared to drumstick muscles. Notably, during the egg-laying period, alterations in hematological parameters linked to oxygen transport, decreased erythropoiesis, and increased values in white blood cell parameters were observed. Changes in blood biochemical parameters signify increased energy requirements in pheasant hens during egg laying, as well as heightened transportation of minerals, proteins, and cholesterol, which accumulate in the eggshell, albumen, and yolk. The elevated metabolic requirements in pheasant hens manifest significantly through increased levels of cholesterol, uric acid, lactates, aspartate aminotransferase (AST), alanine aminotransferase (ALT), calcium, and phosphorus. Simultaneously, there is a noteworthy decrease in plasma total proteins, albumins, glucose, and lactate dehydrogenase (LDH) concentrations. Several challenges persist throughout all production stages, leading to reduced egg yield, compromised egg quality and fertility, as well as increased mortality rates. These issues stem from factors such as high population density, an inappropriate male-to-female sex ratio, inadequate nutrition, and insufficient assessment of the biological quality of hatching eggs.

Effects of Protease and Sex on Skin, Bone and Muscle Yields and Percentages of Major Primal Cuts in Broilers

Summary This study aimed to assess the effects of different dietary levels of the protease enzyme and sex on skin, bone and muscle yields and percentages of breast, drumsticks and thighs as the most valuable carcass parts of broilers. A total of 300 one-day-old, mixed-sex broiler chickens (Cobb 500) were randomly divided into 3 dietary treatments with different levels of protease supplementation (group C: a standard diet without Ronozyme ProAct; group E-I: a diet with 200 mg/kg Ronozyme ProAct and a 4% crude protein reduction compared to the standard diet; and group E-II: a diet with 300mg/kg Ronozyme ProAct and a 6% crude protein reduction compared to the standard diet). All diets were maize- and soybean meal-based. Feed and water were provided ad libitum throughout the 49-day feeding trial. The results obtained indicate that the dietary treatments had no significant effect on skin, bone and muscle yields and percentages of the drumsticks, thighs and breast (P &gt; 0.05), except for the breast muscle weight in the female chickens (especially between the E-I and E-II groups), and the drumstick bone percentage in the males between the C and E-2 groups (P &lt; 0.05). In all three groups, the male chickens exhibited higher weights of skin, muscle and bone in breast, drumsticks and thighs than the female chickens, and the differences were not significant only in the skin weight of drumsticks and thighs (P &gt; 0.05). The females had a higher yield of muscle tissue in breast and drumsticks, a higher percentage of skin in drumsticks and thighs, and a lower percentage of bone in drumsticks and thighs than the males (P &lt; 0.05). Major differences resulted from the effect of broiler sex, whereas the dietary treatments containing 3 levels of protease supplementation had a very small effect on the yields and percentages of skin, bone and muscle in breast, drumsticks and thighs.

Weighted single-step GWAS identified candidate genes associated with carcass traits in a Chinese yellow-feathered chicken population

Carcass traits in broiler chickens are complex traits that are influenced by multiple genes. To gain deeper insights into the genetic mechanisms underlying carcass traits, here we conducted a weighted single-step genome-wide association study (wssGWAS) in a population of Chinese yellow-feathered chicken. The objective was to identify genomic regions and candidate genes associated with carcass weight (CW), eviscerated weight with giblets (EWG), eviscerated weight (EW), breast muscle weight (BMW), drumstick weight (DW), abdominal fat weight (AFW), abdominal fat percentage (AFP), gizzard weight (GW), and intestine length (IL). A total of 1,338 broiler chickens with phenotypic and pedigree information were included in this study. Of these, 435 chickens were genotyped using a 600K single nucleotide polymorphism chip for association analysis. The results indicate that the most significant regions for 9 traits explained 2.38% to 5.09% of the phenotypic variation, from which the region of 194.53 to 194.63Mb on chromosome 1 with the gene RELT and FAM168A identified on it was significantly associated with CW, EWG, EW, BMW, and DW. Meanwhile, the 5 traits have a strong genetic correlation, indicating that the region and the genes can be used for further research. In addition, some candidate genes associated with skeletal muscle development, fat deposition regulation, intestinal repair, and protection were identified. Gene ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analyses suggested that the genes are involved in processes such as vascular development (CD34, FGF7, FGFR3, ITGB1BP1, SEMA5A, LOXL2), bone formation (FGFR3, MATN1, MEF2D, DHRS3, SKI, STC1, HOXB1, HOXB3, TIPARP), and anatomical size regulation (ADD2, AKT1, CFTR, EDN3, FLII, HCLS1, ITGB1BP1, SEMA5A, SHC1, ULK1, DSTN, GSK3B, BORCS8, GRIP2). In conclusion, the integration of phenotype, genotype, and pedigree information without creating pseudo-phenotype will facilitate the genetic improvement of carcass traits in chickens, providing valuable insights into the genetic architecture and potential candidate genes underlying carcass traits, enriching our understanding and contributing to the breeding of high-quality broiler chickens.

The Impact of Different Relative Humidity Levels on the Production Performance, Slaughter Performance, and Meat Quality of White Pekin Ducks Aged 4 to 42 Days

This study aimed to investigate the effects of different humidity levels on the growth performance, slaughter performance, and meat quality of Pekin ducks through the artificial control of humidity, and to identify the suitable environmental humidity for Pekin duck growth. A completely randomized single-factor design was employed, selecting 144 newly hatched male Pekin ducks with healthy and similar BW (body weight) (60.92 g ± 4.38). These ducks were randomly assigned to four groups (A (RH (relative humidity) = 60%), B (RH = 67%), C (RH = 74%), D (RH = 81%)), with 12 ducks and 3 replicates in each group. The ducks were raised in a climate-controlled room for 42 days with ad libitum access to feed and water. BW and feed intake were measured every 3 days, and slaughter performance and meat quality were assessed at 42 days. There was no significant difference in the ADG (average daily gain) from 1 to 21 days (p &gt; 0.05). The ADFI (average daily feed intake) of Group D was significantly lower than that of Groups A, B, and C (p &lt; 0.05), with no significant differences between Groups A, B, and C (p &gt; 0.05). At 42 days, the BW, ADG, and ADFI of Groups A and C were significantly higher than those of Group D (p &lt; 0.05), with no significant differences among Groups A, B, and C (p &gt; 0.05). Group C had a significantly higher breast muscle weight, breast muscle ratio, liver weight, and liver index than Groups B and D (p &lt; 0.05), with no significant differences between Groups A, B, and D (p &gt; 0.05). The meat shear force in Group C was significantly lower than that in Groups A, B, and D (p &lt; 0.05). The L* (brightness) of Group C was significantly lower than that of Group A (p &lt; 0.05), and the a* (redness) value of Group C was significantly higher than that of Groups A and B (p &lt; 0.05), with no significant difference compared to Group D (p &gt; 0.05). Group B had a significantly higher cooking loss than Groups A, C, and D (p &lt; 0.05), with no significant differences among Groups A, C, and D (p &gt; 0.05). Under 26 °C conditions, Pekin ducks perform best in terms of the production performance and feed efficiency, with high-quality meat, especially when reared at 74% humidity.

Content of amino acids and biogenic amines in stored meat as a result of a broiler diet supplemented with β-alanine and garlic extract

Poultry meat is a highly esteemed product among consumers. However, the emphasis on increasing body weight has led to a rise in the proportion of rapidly shrinking fibers, adversely affecting the quality and shelf life of poultry meat. With a growing awareness of dietetics among consumers, there is an increasing challenge to produce chicken meat that is not only free of antibiotics but also beneficial for dietary and health reasons. Biogenic amines (BA) can serve as indicators of meat freshness and quality. While they play vital roles in the body, excessive consumption of BA can have toxic and carcinogenic effects. The objective of this study was to examine the impact of supplementing feed with garlic extract and β-alanine (β-Ala) on the formation of BA and amino acid (AA) levels in the breast and leg muscles of chickens stored under aerobic chilling conditions. The muscles were obtained from chickens fed with garlic extract and β-Ala in quantities of 0.5 and 2% for each additive, as well as 0.5 and 2% of their combination. Analyses were conducted on d 1, 3, 5, 7, and 10 of storage. β-Ala supplementation increased the proportion of this AA in breast (P < 0.01) and leg muscles (P < 0.01), along with a rise in the proportion of nonessential AA (NEAA; sum of aspartic, aspartic acid, glutamic, glutamic acid, serine, β-Ala, and proline) (P < 0.01). The levels of BA changed during storage in breast and leg muscles (P < 0.001). The applied diet significantly influenced the formation of putrescine (P = 0.030), phenylethylamine (P = 0.003), agmatine (P = 0.025), and total BA (P < 0.001) in breast muscles. On the 10 d of storage, the breast muscles exhibited the lowest BA index (BAI) in the group, with a diet supplemented with 0.5% garlic extract and 0.5% β-Ala (P < 0.05). The leg muscles showed a similar BA trend as the breast muscles. These supplements may be utilized in production to augment the protein content of chicken muscles and potentially decrease the BAI index during meat storage.