Search Results (5)

The absorption, transport, and distribution of antibiotics in animals are influenced by the composition and function of the intestinal microbial community. However, most existing studies have focused on intensive farming systems involving the artificial addition of antibiotics. For free-range local chicken breeds in mountainous areas without antibiotic additives, systematic research on the presence of antibiotic residues in their muscle tissues and their association with the gut microbiota is lacking. Therefore, in this study, mountainous free-range Lueyang black-bone chickens were selected as the research subjects, employing non-targeted metabolomics and microbiomics to analyze the distribution of antibiotics in intestinal tissues (duodenum and caecum) and muscle tissues (breast and leg muscles), and their correlations with the intestinal microbiota. Metabolomics detected 47 antibiotics in intestinal tissues and 22 in muscle tissues, with 9 common to both tissues, including clinically and veterinary relevant antibiotics such as oxacillin, kanamycin, and tobramycin. Microbiomics analysis indicated significant differences in microbial communities between the duodenum and caecum at the genus level. LEfSe analysis identified seven characteristic genera in the duodenum (e.g., Bacteroides, Alistipes) and five in the caecum (e.g., Lactobacillus, Ureaplasma). Pearson correlation analysis further revealed that these shared antibiotics were significantly associated with the differential genera in the intestine. For instance, oxacillin exhibited a positive correlation with both Bacteroides and Alistipes. Kanamycin was positively correlated with Alistipes, whereas tobramycin showed a negative correlation with Bacteroides. These results indicate that antibiotic residues were present in both intestinal and muscle tissues of Lueyang black-bone chickens raised under free-range mountainous conditions. The nine antibiotics common to both tissues are likely absorbed in the intestines and transported to muscles via the bloodstream. It is hypothesized that the gut microbiota may play a potential regulatory role in this process, providing a theoretical basis for understanding microecological mechanisms under environmental antibiotic exposure. Full article

The Lueyang black-bone chicken represents a distinct indigenous avian breed native to China and it is a slow-growing broiler breed. The gut, whose primary function is to digest food and absorb nutrients, is also home to a large and diverse microbial community. The intestinal morphology, intestinal metabolites, and gut microbiota are critical determinants of nutrient utilization efficiency and immune health in poultry. This study investigates the impact of two distinct rearing modalities—cage-raised (CR) and cage-free (CF)—on the intestinal morphology, intestinal metabolites, and gut microbiota of the duodenum and cecum in Lueyang black-bone chickens. Additionally, we have integrated metabolomics and microbiome analyses. Morphological assessments revealed that, in comparison to the CR group, the CF group exhibited a significant increase in duodenal villi height (VH) and crypt depth (CD) (p < 0.01). Furthermore, there was a notable increase in the number of intestinal inflammatory cells within the CF group. Non-targeted metabolomics indicated an upregulation of omega-3 series polyunsaturated fatty acids and bile acid metabolites in the CR group. Conversely, the CF group demonstrated significantly elevated levels of lysophosphatidylcholine (LPC) and phosphatidylcholine (PE) in the intestine. Microbiome analysis revealed that in the duodenum, beneficial bacteria (e.g., Lactobacillus) were the dominant genera in the CF group, while the Bacteroides predominate in the CR group. Correlation analyses indicated a positive association between LPC levels and the presence of eight bacterial genera, including Ureaplasma. The omega-3 series polyunsaturated fatty acids were positively correlated with three bacterial genera, such as Flavobacterium. Notably, bile acid metabolites exhibited a significant positive correlation with Rikenellaceae_RC9_gut_group. In conclusion, this study provides novel insights into how rearing methods influence intestinal morphology, intestinal metabolites, and gut microbiota, offering a new perspective for the scientific management of poultry with the premise of ensuring animal health and welfare. Full article

The Lueyang black-bone chicken is a specific native chicken strain in China. This study aimed to investigate the effects of different rearing systems on the meat quality of Lueyang black-bone chickens. Six hundred Lueyang black-bone hens were randomly divided into two groups at 7 weeks of age and raised in cage and cage-free systems for 20 weeks. The carcass yield, meat quality, and total metabolites were measured in both the leg and breast muscles. By comparison, the carcass yield of hens in the cage-free (CF) group (1.26 ± 0.09 kg) was significantly lower than that in the caged rearing (CR) group (1.52 ± 0.15 kg). However, the shear force of leg muscles in the CF group (27.98 ± 2.43 N) was significantly greater than that in the CR group (24.15 ± 1.93 N). In addition, six samples from each group were randomly selected and their metabolites were detected by the non-targeted metabolomics technique. Among these metabolites, 408 and 354 significantly differentially abundant metabolites were identified in breast and leg muscles, which were mainly involved in glycerophospholipid metabolism, unsaturated fatty acid biosynthesis, arginine and proline metabolism, and nucleotide metabolism. We found that the levels of 19 phospholipids, mainly phosphatidylcholines and lysophosphatidylcholines, were significantly greater in the CF group than in the CR group. Additionally, the contents of eight unsaturated fatty acids, linoleic acid, and linolenic acid were dramatically greater in the CF group than in the caged group. The accumulation of 4-hydroxy-proline, glutamate, and adenosine 3′-monophosphate (AMP) was enhanced in the CF group. Moreover, many more volatile organic compounds were identified in the muscles of the cage-free group, enhancing the flavor of the chicken meat. In conclusion, the cage-free rearing mode facilitates the accumulation of nutrients and flavor substances in the chicken meat and is a better rearing system for Lueyang black-bone chickens. Full article

Chilled and cut chicken is preferred by consumers for its safeness and readiness to cook. To evaluate the quality characteristics of various chilled chicken products, differences in volatile organic components (VOCs) of six different cut parts (breast, back, leg, heart, liver, and gizzard) of Lueyang black chicken were characterized through gas chromatography–ion mobility spectroscopy (GC-IMS) combined with stoichiometry. A total of 54 peaks in the signal of VOCs were detected by GC-IMS, and 43 VOCs were identified by qualitative analysis. There were 22 aldehydes (20.66–54.07%), 8 ketones (25.74–62.87%), 9 alcohols (4.17–14.69%), 1 ether (0.18–2.22%), 2 esters (0.43–1.54%), and 1 furan (0.13–0.52%), in which aldehydes, ketones, and alcohols were the main categories. Among the six cut parts, the relative content of aldehydes (54.07%) was the highest in the gizzard, and the relative content of ketones (62.87%) was the highest in the heart. Meanwhile, the relative content of alcohols (14.69%) was the highest in the liver. Based on a stable and reliable predictive model established by orthogonal partial least squares–discriminant analysis (OPLS-DA), 3-hydroxy-2-butanone (monomer and dimer), acetone, 2-butanone monomer, hexanal (monomer and dimer), isopentyl alcohol monomer, and n-hexanol monomer were picked out as characteristic VOCs based on variable importance in projection (VIP value > 1.0, p < 0.05). Principal component analysis (PCA) and the clustering heatmap indicated that the characteristic VOCs could effectively distinguish the six cut parts of Lueyang black chicken. The specific VOCs responsible for flavor differences among six different cut parts of Lueyang black chicken were hexanal (monomer and dimer) for the gizzard, 2-butanone monomer and hexanal dimer for the breast, hexanal monomer for the back, 3-hydroxy-2-butanone monomer for the leg, 3-hydroxy-2-butanone (monomer and dimer) for the heart, and acetone and isopentyl alcohol monomer for the liver. These findings could reveal references for quality assessment and development of chilled products related to different cut parts of Lueyang black chicken in the future. Full article

The quality of poultry products depends on genotype, rearing system, and environment. The aim of this study was to investigate the effects of different rearing systems on meat quality, amino acid composition, and breast muscle transcriptome from Lueyang black-bone chickens. Lueyang black-bone chickens (n = 900) were randomly divided into three groups (cage, flat-net, and free-range groups), with three replicates per group (100 chickens per replicate). At 16 weeks, a total of 36 healthy chickens (six males and six females per group) were collected, and their breast muscles were sampled to detect meat quality parameters, amino acid composition, and fatty acid contents. Furthermore, breast muscles from six random hens in each group were used for RNA-seq analysis. The results revealed that the values of pH, shear force, inosine monophosphate (IMP), palmitic acid, and linoleic acid in the free-range group were significantly higher than those in the caged group (p < 0.05). Fat content in the free-range group was significantly lower than in the caged and flat-net groups (p < 0.05). Glutamate (Glu) levels, the amino acid crucial for the umami taste, was significantly higher in the free-range group than in the caged group (p < 0.05). Meanwhile, there was no significant difference between the free-range and flat-net groups (p > 0.05). The breast muscle transcriptome results showed that there were 291, 131, and 387 differently expressed genes (DEGs) among the three comparison groups (caged vs. free-range, flat-net vs. caged, and flat-net vs. free-range, respectively) that were mainly related to muscle development and amino acid metabolism pathways. To validate the accuracy of the transcriptome data, eight genes (GOS2, ASNS, NMRK2, GADL1, SMTNL2, SLC7A5, AMPD1, and GLUL) which relate to fat deposition, skeletal muscle function, and flavor formation were selected for Real-time Quantitative PCR (RT-qPCR) verification. In conclusion, these results suggested that rearing systems significantly influenced the meat quality and gene expression of Lueyang black-bone chickens. All the data proved that free-range and flat-net systems may provide better flavor to consumers by affecting the deposition of flavor substances and the expression of related genes. These findings will provide a valuable theoretical basis for the rearing system selection in the poultry industry. Full article