Photoperiodic effect on the testicular transcriptome in broiler roosters

Area of Science:

• Animal Science
• Reproductive Biology
• Genomics

Background:

• Photoperiod significantly influences avian reproduction.
• Limited data exists on photoperiod's impact on broiler rooster testicular gene expression.

Purpose of the Study:

• To investigate the effects of different photoperiodic regimes on broiler breeder rooster testicular gene expression.
• To identify genes and pathways involved in photoperiod-induced testicular changes.

Main Methods:

• Broiler roosters were exposed to short day (8L:16D), control (12.5L:11.5D), or long day (16L:8D) photoperiods for 4 weeks.
• Testicular histology and sperm counts were assessed.
• Testicular transcriptomes were analyzed using RNA sequencing (RNA-Seq) and validated with quantitative real-time PCR.

Main Results:

• Longer photoperiods significantly increased seminiferous tubule area and sperm count (p < .01).
• RNA-Seq identified 387 upregulated and 1,052 downregulated genes in the long day group compared to the short day group.
• Key genes in testicular development (e.g., HSP90, ERK1, PI3K, AMPK, BCL-6, Smad3) and enriched pathways (mTOR, FoxO, TGF-β, insulin signaling) were identified.

Conclusions:

• A 16-hour photoperiod for 4 weeks promotes spermatogenesis and increases testicular size in broiler roosters.
• The mTOR, FoxO, TGF-β, and insulin signaling pathways are implicated in mediating the effects of photoperiod on rooster reproduction.