Complete mitochondrial genome sequence and gene organization of Chinese indigenous chickens with phylogenetic considerations

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.

The complete mitochondrial genome of the Dongan black chicken and its phylogenetic analyses

Dongan black chicken (Gallus gallus domesticus, DBC) is one of the famous native breed of Hunan province in China. The complete mitochondrial genome sequence plays an important role in the accurate determination of phylogenetic relationships among metazoans. It is the first time that the complete mitochondrial genome sequence of the DBC was reported. The total length of the mtDNA is 16,785 bp, It contains the typical structure, including 22 transfer RNA genes, 2 ribosomal RNA genes, 13 protein-coding genes and 1 non-coding control region (D-loop region). The overall composition of the mtDNA was estimated to be 30.27% for A, 23.78% for T, 32.46% for C, and 13.49% for G. Phylogenetic analyses using N-J computational algorithms showed that the analyzed 21 Galliformes species are divided into four major clades: Phasianidae, Numidiidae, Odontophoridae, and Megapodiidae. In addition, our work confirmed that DBC and Taoyuan chicken (TYC) have a close genetic relationship with fellow tribal members Xuefeng black-boned chicken (XBC) and Huang Lang chicken (HLC). Meanwhile, we also found that DBC and TYC have highly similar genetic relationship. This work will provide an important data set for the study of genetic mechanism of chicken in Hunan province.

Corticosterone-Induced Lipogenesis Activation and Lipophagy Inhibition in Chicken Liver Are Alleviated by Maternal Betaine Supplementation

Background

We have shown previously that in ovo betaine injection can prevent nonalcoholic fatty liver induced by glucocorticoid exposure in chickens; yet it remains unknown whether feeding betaine to laying hens may exert similar effects in their progeny.

Objective

In this study, we fed laying hens a betaine-supplemented diet, and the progeny were later exposed chronically to corticosterone (CORT) to test hepatoprotective effects and further elucidate underlying mechanisms.

Methods

Rugao yellow-feathered laying hens (n = 120) were fed a basal (control, C) diet or a 0.5% betaine-supplemented (B) diet for 28 d before their eggs were collected for incubation. At 49 d of age, male chickens selected from each group were daily injected subcutaneously with solvent (15% ethanol; vehicle, VEH) or CORT (4.0 mg/kg body mass) for 7 d to establish a fatty liver model. Chickens in the 4 groups (C-VEH, C-CORT, B-VEH, and B-CORT) were killed at day 57. Plasma and hepatic triglyceride (TG) concentrations, as well as the hepatic expression of genes involved in lipogenesis and lipophagy, were determined.

Results

CORT induced a 1.6-fold increase in the plasma TG concentration (P < 0.05) and a 1.8-fold increment in the hepatic TG concentration (P < 0.05), associated with activation of lipogenic genes (70-780%). In contrast, lipophagy and mitochondrial β-oxidation genes were inhibited by 30-60% (P < 0.05) in CORT-treated chickens. These CORT-induced changes were completely normalized by maternal betaine supplementation or were partially normalized to intermediate values that were significantly different from those in the C-VEH and C-CORT groups. These effects were accompanied by modifications in CpG methylation and glucocorticoid receptor binding to the promoters of major lipogenic and lipophagic genes (P < 0.05).

Conclusions

These results indicate that maternal betaine supplementation protects male juvenile chickens from CORT-induced TG accumulation in the liver via epigenetic modulation of lipogenic and lipophagic genes.

Identification and Differential Abundance of Mitochondrial Genome Encoding Small RNAs (mitosRNA) in Breast Muscles of Modern Broilers and Unselected Chicken Breed

Background: Although small non-coding RNAs are mostly encoded by the nuclear genome, thousands of small non-coding RNAs encoded by the mitochondrial genome, termed as mitosRNAs were recently reported in human, mouse and trout. In this study, we first identified chicken mitosRNAs in breast muscle using small RNA sequencing method and the differential abundance was analyzed between modern pedigree male (PeM) broilers (characterized by rapid growth and large muscle mass) and the foundational Barred Plymouth Rock (BPR) chickens (characterized by slow growth and small muscle mass). Methods: Small RNA sequencing was performed with total RNAs extracted from breast muscles of PeM and BPR (n = 6 per group) using the 1 × 50 bp single end read method of Illumina sequencing. Raw reads were processed by quality assessment, adapter trimming, and alignment to the chicken mitochondrial genome (GenBank Accession: X52392.1) using the NGen program. Further statistical analyses were performed using the JMP Genomics 8. Differentially expressed (DE) mitosRNAs between PeM and BPR were confirmed by quantitative PCR. Results: Totals of 183,416 unique small RNA sequences were identified as potential chicken mitosRNAs. After stringent filtering processes, 117 mitosRNAs showing >100 raw read counts were abundantly produced from all 37 mitochondrial genes (except D-loop region) and the length of mitosRNAs ranged from 22 to 46 nucleotides. Of those, abundance of 44 mitosRNAs were significantly altered in breast muscles of PeM compared to those of BPR: all mitosRNAs were higher in PeM breast except those produced from 16S-rRNA gene. Possibly, the higher mitosRNAs abundance in PeM breast may be due to a higher mitochondrial content compared to BPR. Our data demonstrate that in addition to 37 known mitochondrial genes, the mitochondrial genome also encodes abundant mitosRNAs, that may play an important regulatory role in muscle growth via mitochondrial gene expression control.