Investigating the impact of pigmentation variation of breast muscle on growth traits, melanin deposition, and gene expression in Xuefeng black-bone chickens.

The blackness traits, considered an important economic factor in the black-bone chicken industry, still exhibits a common phenomenon of significant difference in blackness of breast muscle. To improve this phenomenon, this study compared growth traits, blackness traits, and transcriptome of breast muscles between the High Blackness Group (H group) and Low Blackness Group (L group) in the Xuefeng black-bone chickens. The results are as follows: 1) There was no significant difference in growth traits between the H group and the L group (P > 0.05). 2) The skin/breast muscle L values in the H group were significantly lower than those in the L group, while the breast muscle melanin content exhibited the opposite trend (P < 0.05). 3) A significant negative correlation was observed between breast muscle melanin content and skin/breast muscle L value (P < 0.05), and skin L value exhibiting a significant positive correlation with breast muscle L value (P < 0.05). 4) The breast muscle transcriptome comparison between the H group and L group revealed 831 and 405 DEGs in female and male chickens, respectively. This included 37 shared DEGs significantly enriched in melanosome, pigment granule, and the melanogenesis pathway. Seven candidate genes (DCT, PMEL, MLANA, TYRP1, OCA2, EDNRB2, and CALML4) may play a crucial role in the melanin production of breast muscle in Xuefeng black-bone chicken. The findings could accelerate the breeding process for achieving desired levels of breast muscle blackness and contribute to the exploration of the mechanisms underlying melanin production in black-bone chickens.

Genes influencing deposition of melanin in breast muscle of the Xuefeng black bone chicken based on bioinformatic analysis.

The Xuefeng black bone chicken (XFBC) represents an important poultry genetic resource. However, the darkness in breast muscle is heterogeneous. The molecular genetic mechanisms underlying melanogenesis of breast muscle in XFBC remains unclear. This study used RNA-seq to compare the difference in transcriptome between hyperpigmentation and hypopigmentation of breast muscle. Six cDNA libraries were constructed for hyperpigmentation and hypopigmentation groups in XFBC. We identified 395 differently expressed genes (DEGs) between hyperpigmentation and hypopigmentation group (P < 0.05, |log2FC|≥1). Gene ontology (GO) enrichment and the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis indicated several differentially enriched biological functions and pathways involved in melanogenesis of the breast muscle. Gene set enrichment analysis (GSEA) GO analysis identified two significant gene sets, including the pathways of pigment metabolic process and transmembrane receptor protein tyrosine kinase activity. GSEA-KEGG analysis identified the process of tyrosine metabolism and several genes related with melanogenesis in breast muscle of the XFBC. The protein-protein interaction network was constructed and eight genes were clustered in the module. We identified nine hub genes, including TYR, TYRP1, DCT, GPR143, MLANA, SLC24A5, GPNMB, MLPH, and EDNRB2. Taken together, the DEGs and hub genes identified in the study provide a solid basis for the study of the genetic regulatory mechanisms involved the melanogenesis in the breast muscle of the XFBC.

Modulation of intestinal morphology and microbiota by dietary Macleaya cordata extract supplementation in Xuefeng Black-boned Chicken.

Antibiotics are commonly overused to prevent livestock from diseases and to increase production performance. As potential substitutes of antibiotics, plant extracts have attracted the attention of researchers. It was known to all that addition of Macleaya cordata extract (MCE) to the food could advance immunity, intestinal health and animal performance. Thus, it was conducted to investigate the influence of MCE (0, 100, 150 and 200 mg/kg, with six replicate pens/treatment and 24 hens/pen) on intestinal morphology and microbial diversity in different intestinal segments in Xuefeng black-boned chicken in this study. The results showed that MCE supplement (100, 150 and 200 mg/kg) significantly diminished (P < 0.05) the crypt depth of the jejunum as compared to basal diet group. The 100 mg/kg group displayed a marked increase (P < 0.05), compared with 0 and 200 mg/kg group, in ileum microbial diversity as represented by the Shannon's index. In the cecum, treatment of MCE significantly decreased (P < 0.01) the Firmicutes, but Deferribacteres in 200 mg/kg MCE group were significantly raised (P < 0.05). In conclusion, we found that MCE improved intestinal morphology and reduced the crypt depth in jejunum. Together, addition of 200 mg/kg MCE modulated intestinal microbiota, increased beneficial bacteria such as Lactobacillus. Adding 100 mg/kg MCE to diet increased bacterial community diversity and relative abundance in jejunum and ileum, but had no effect on cecum microbial diversity.

Black Soldier Fly (Hermetia illucens) Larvae Meal Modulates Intestinal Morphology and Microbiota in Xuefeng Black-Bone Chickens.

The addition of Hermetia illucens larvae meal (HILM) to the feed could contribute to particular antimicrobial and intestinal health in animal husbandry. This study was conducted to investigate the effects of HILM on intestinal morphology and microbial diversity in different intestinal segments of Xuefeng black-bone chickens. All of 432 birds (45 weeks old) were randomly assigned to four equal groups with six replicates and 18 hens in each replicate: (A) basal diet, (B) basal diet with 1% HILM, (C) basal diet with 3% HILM, and (D) basal diet with 5% HILM. The results showed that, compared with the basal diet group, the HILM supplement significantly increased the abundance-based coverage estimator (ACE) and Chao index in cecum (p < 0.05). Diet with 1% HILM significantly increased the villus height (VH) of the duodenum (p < 0.05) and cecum microbial diversity as represented by the Simpson index (p < 0.05). In particular, 1% HILM displayed a markedly increase in the genus unclassified Bacteroidales (cecum, p < 0.05). A basal diet with 3% HILM markedly increased the beneficial genus Romboutsia (jejunum, p < 0.05). Also, principal component analysis (PCA) cluster analysis showed that 3% of HILM was more individual than other groups (p < 0.05). However, 5% HILM decreased the VH and the ratio of villus height to crypt depth (VH/CD) of the jejunum and increased beneficial bacteria such as Staphylococcus (p < 0.05), which was regarded as pathogenetic genera. In conclusion, we found that HILM improved intestinal morphology and increased microbiological diversity and species abundance. Together, dietary supplementation of 1 or 3% HILM might benefit the intestinal morphology and intestinal microbiota of Xuefeng black-bone chicken. However, the addition of 5% HILM could decrease VH and the ratio of VH/CD of the jejunum and increased pathogenetic genera. HILM was an excellent protein substitute for Xuefeng black-bone chickens, which could meet the nutritional requirements under the condition of less feed. These results provide information for HILM meal as an alternative source of soybean meal in Xuefeng black-bone chickens' feed.

Effects of Macleaya cordata extract on laying performance, egg quality, and serum indices in Xuefeng black-bone chicken.

The abuse of antibiotic growth promoters (AGPs) in feed has led to drug resistance and ecological damage would threaten human health eventually. Natural plants have become a hotspot in the research and application of substituting AGPs because of their advantages of safety, efficiency, and availability. This study was conducted to investigate the effects of Macleaya cordata extract (MCE) in the diet of Xuefeng black-bone chicken on laying performance, egg quality, and serum indices. In this study, 576 birds (47-week-old) were evenly distributed between 4 treatments with 6 replicates of 24 hens each. The control group was fed a basal diet without MCE and the remaining groups received 100, 150, or 200 mg/kg MCE for 84 d. Results revealed that the strength and thickness of the eggshell increased significantly with the dietary addition of MCE (P < 0.05). The serum concentrations of glutathione peroxidase increased in the MCE groups (P < 0.01). Simultaneously, progesterone, follicle stimulating hormone, estradiol as well as serum luteinizing hormone levels also increased with the addition of MCE (P < 0.05). Compared with the control group, supplementation of MCE significantly decreased the tumor necrosis factor-α and interleukin-6 levels (P < 0.01). In summary, it was concluded that diet addition of 200 mg/kg MCE ameliorated egg quality, enhanced anti-oxidation and immune activity, and regulated hormone secretion of Xuefeng black-bone chicken.

Comparison of overfed Xupu and Landes geese in performance, fatty acid composition, enzymes and gene expression related to lipid metabolism.

OBJECTIVE: The aim of this study was to compare overfeeding performance, fatty acid composition, blood chemistry, enzymes and genes expression overfed Xupu and Landes geese. METHODS: Sixty male Xupu geese (80 d) and Landes geese (80 d) were selected. After a period of one-week of pre-overfeeding, Xupu and Landes geese were overfed three meals of 550 and 350 g/d, respectively, of a high-carbohydrate diet in the first week of the overfeeding period. The next week, geese were given four meals of 1,200 and 850 g/d, respectively, over 8 to 14 d. Finally, geese were given five meals of 1,600 and 1,350 g/d, respectively, for the last two weeks. RESULTS: After overfeeding for 28 d: Compared with Landes geese, Xupu geese liver weight and liver-to-body weight ratio decreased (p<0.05), while final weight, slaughter weight, total weight gain, abdominal fat weight, and feed-to-liver weight ratio increased (p<0.05). The levels of elaidic acid (C18:1t9), oleic acid (C18:1n-9), eicosenoic acid, and arachidonic acid in the liver of Xupu geese significantly increased (p<0.05), and the levels of myristic acid and stearic acid significantly decreased (p<0.05), while methyleicosanoate acid significantly increased (p<0.05). Xupu geese had higher plasma concentrations of triglyceride and very low density lipoprotein cholesterol (p<0.05), and decreased activities of alanine aminotransferase, aspartate aminotransferase, and lipase (LPS) (p<0.05). Landes geese had higher LPS activity (p<0.05), but lower cholinesterase activity (p<0.05) when compared with Xupu geese. The mRNA expression levels of fatty acid dehydrogenase (FADS) gene, elongase of longchain fatty acid 1 (ELOVL1) gene, ELOVL5, and acyl-Co A: cholesterol acyltransferase 2 (ACAT2) gene were significantly upregulated (p<0.05) in Landes goose when compared with Xupu geese. CONCLUSION: This study demonstrates that the liver production performance of Landes geese was better than that of Xupu geese to some extent, which may be closely related to LPS activity, as well as the expression of FADS, ELOVL1, ELOVL5, and ACAT2.

Montmorillonite improved the intestinal mucosal barrier functions of laying hens in late production.

This study was conducted to investigate the effects of dietary supplementation with montmorillonite (MMT) on performance, intestinal endotoxin concentration, gut mucosal oxidation status, intestinal morphology and permeability, and immunological barrier function of laying hens during late production. Four hundred and eighty 75-week-old laying hens (Lohmann Brown) were randomly assigned to five treatments with eight replicates per treatment and 12 hens in each replicate. The hens were fed the basal diet supplemented with 0 (control), 0.3, 0.6, 0.9, or 1.2 g MMT/kg for 70 days. Compared with the control, supplemented with 0.9 g MMT/kg increased egg mass significantly (p < 0.05) during weeks 1-5 of the experiment. Supplemented with 0.6 and 0.9 g MMT/kg also increased the endotoxin concentration in the ileal digesta (p < 0.05), but decreased the MDA concentration in the ileum significantly (p < 0.05). The T-AOC in the jejunum of the group fed 0.3 g MMT/kg was significantly increased (p < 0.05). Compared with the control, the villus height:crypt depth of ileum from the groups fed 0.6, 0.9, and 1.2 g MMT/kg increased significantly (p < 0.05). The sIgA concentration of jejunum in the groups fed 0.6 and 0.9 g MMT/kg was higher (p < 0.05) than the control. The MMT supplementation linearly increased (p < 0.05) the mRNA expression of claudin-1 and claudin-5 in the jejunum. Dietary MMT supplementation down-regulated the mRNA expression of NF-κB P65 and TNF-α in the jejunum in a linear and quadratic manner (p < 0.05). The IL-1ß mRNA expression of jejunum in the group fed 0.6 g MMT/kg was lower (p < 0.05) than the control. In conclusion, dietary supplementation with MMT may improve the gut barrier functions and suggests that 0.9 g/kg of MMT in diets may be the optimal supplemental level for laying hens in late production.

Effects of Bacillus subtilis C-3102 on production, hatching performance, egg quality, serum antioxidant capacity and immune response of laying breeders.

To investigate the supplemental effects of Bacillus subtilis C-3102 on the production, hatching performance, egg quality, serum antioxidant capacity and immune response of laying breeders, a total of 480 Xuefeng black-bone (25-week-old) hens were randomly assigned into four treatment groups: Hens fed the basal diets with 0 (CON), 3.0 × 105 (BS-1), 6.0 × 105  cfu/g (BS-2) and 9.0 × 105 (BS-3) cfu/g of B. subtilis C-3102. As the B. subtilis C-3102 level increased, egg weight (linear, p < 0.01; quadratic, p = 0.003), fertility (linear, p = 0.021; quadratic, p = 0.059), hatchability (linear, p = 0.038; quadratic, p = 0.119) and yolk colour (linear, p = 0.006; quadratic, p = 0.021) increased in a linear or quadratic manner. Yolk index increased quadratically (linear, p = 0.054; quadratic, p = 0.017), and eggshell thickness (linear, p = 0.036; quadratic, p = 0.128), the activity of GSH-Px (linear, p = 0.024; quadratic, p = 0.078), the concentration of IgM (linear, p = 0.016; quadratic, p = 0.056) and the level of AIV-Ab (linear, p = 0.034; quadratic, p = 0.103) in the serum increased linearly as dietary supplementation of B. subtilis C-3102 increased. The results showed that dietary treatments did not affect egg production, feed conversion ratio, egg mass, hatchability of fertile eggs, eggshell-breaking strength, egg-shape index, yolk percentage, Haugh unit, T-SOD, T-AOC, MDA, IgA and IgG concentrations and the level of NDV-Ab in the serum. In conclusion, dietary supplementation of 9.0 × 105  cfu/g B. subtilis C-3102 in laying breeders diets may be a feasible means of effectively increasing egg weight, fertility and hatchability, and improving egg quality such as eggshell thickness, yolk index and yolk colour. Besides, B. subtilis C-3102 can enhance the activity of GSH-Px, the concentration of IgM and the level of AIV-Ab in the serum.