This investigation aimed to use transcriptome analysis to explore the key genes and signaling pathways through which photoperiod impacts reproductive hormone secretion in roosters. 240 forty-two-day-old Chahua No.2 roosters were randomly assigned to four groups: simulated natural light (Ⅰ), 12L:12D (Ⅱ), 16L:8D (Ⅲ), and 20L:4D (Ⅳ), with 6 replicates per group and 10 roosters in each replicate. Blood samples were collected at 91 days and 140 days after hatching to measure the levels of various reproductive hormones. Subsequently, the two groups with the most significant differences in reproductive hormone levels were chosen for in-depth transcriptomic analysis. Select the two groups with the greatest differences in reproductive hormones for transcriptomic analysis. Results showed that at 90 days of age, the duration of light exposure had no significant effect on the levels of GnRH, FSH, and LH (P > 0.05); at 140 days of age, with prolonged exposure to light, the levels of GnRH, FSH, and LH in the blood will significantly or extremely significantly increase (P < 0.05). Transcriptome analysis of pituitary tissues identified 467 significantly differentially expressed genes, with 133 genes being significantly downregulated and 334 genes being significantly upregulated. Key signaling pathways identified included calcium signaling pathway, neuroactive ligand-receptor interaction. Transcriptome analysis of hypothalamus tissues identified a total of 1374 significantly differentially expressed genes, of which 693 were significantly downregulated and 681 were significantly upregulated. A significantly enriched neuroactive ligand-receptor interaction signaling pathway was identified. The results indicate that the extension of photoperiod affects the expression of genes such as ATP2A3, ATP2B1, MCU, GnRH-I, TRH in the hypothalamus and pituitary by regulating the calcium signaling pathway and the neuroactive ligand-receptor interaction, thereby regulating the secretion of GnRH, FSH, and LH.

This study investigated the effects of ultraviolet A (UVA) radiation on the blackness traits of Xichou Black-boned Chickens and their underlying molecular mechanisms through combined transcriptomic and metabolomic analyses. A total of 240 one-day-old Xichou Black-boned Chickens were randomly divided into four groups and exposed to different durations of UVA radiation at an intensity of 47 μW/cm². Skin blackness was measured at 1, 22, and 45 days of age, and blood and pectoral skin samples were collected at 45 days for analysis. The results showed that an exposure time of 1 h per day at 47 μW/cm² was ideal for enhancing the blackness traits of the chickens, while exposure times exceeding 3 h led to a significant increase in mortality. Omics studies revealed that the mTOR pathway and tryptophan metabolism pathway are potentially involved in the biological processes by which UVA radiation affects the blackness traits of Xichou Black-boned Chickens, with the FZD3 gene being a candidate gene for these effects. These findings provide theoretical foundations and references for understanding the molecular regulation of blackness traits in these chickens and the potential application of UVA radiation in their production.

This study investigated the impact of light duration on Testosterone secretion in Chahua No.2 roosters, utilizing combined Transcriptome and Metabolome analyses to uncover critical genes, Metabolites, and signaling pathways. We randomly selected 240 Chahua No.2 roosters at 42 days old and divided them into four groups: simulated natural light (Ⅰ), 12L:12D (Ⅱ), 16L:8D (Ⅲ), and 20L:4D (Ⅳ), each group has 6 replicates, with 10 chickens per replicate. Blood samples were collected at 91 and 140 days post-hatch to measure Testosterone levels. Results showed that at 91 days, group Ⅳ had significantly higher Testosterone levels than groups Ⅰ, Ⅱ, and Ⅲ (P < 0.01), with group Ⅲ also higher than groups Ⅰ (P < 0.01) and Ⅱ (P < 0.05). By 140 days, group Ⅳ maintained significantly higher Testosterone than groups Ⅰ and Ⅱ (P < 0.01) and higher than group Ⅲ (P < 0.05), while group Ⅲ was also elevated compared to groups Ⅰ and Ⅱ (P < 0.05). Testicles Transcriptomics analysis revealed 891 differentially expressed genes, including 479 down-regulated and 412 up-regulated genes. Key signaling pathways identified included Steroid Hormone Biosynthesis, Cytochrome P450, and retinol metabolism. Testicles Metabolomics analysis identified 174 differential Metabolites, with 91 up-regulated and 83 down-regulated, focusing on pathways like Amino Sugar Metabolism and Tryptophan Metabolism. Integrated analysis pinpointed 19 common signaling pathways, with the top ten including Cytochrome P450, tyrosine metabolism, and amino acid biosynthesis. Our findings indicate that extending light duration enhances Testosterone secretion in roosters. Through comprehensive transcriptomic and metabolomic analyses, we established that pathways associated with steroid hormone synthesis and Cytochrome P450 play a crucial role in light duration-regulated Testosterone secretion, highlighting key genes such as CYP11A1, CYP17A1, and HSD3B1, alongside Metabolites like ergosterol-5,7,22,24(28)-tetraene-3beta-alcohol.