BIONATURE

Thyroid stimulating hormone beta (TSHβ) plays a central role in avian growth and development by regulating thyroid hormone production, thereby influencing metabolism, skeletal formation and growth rate. This study investigated growth performance and TSHβ gene expression in two broiler breeds (FUNAAB Alpha and Ross 308), assess breed and sex specific variations and their association with growth traits. A total of 200 day-old chicks (100 per breed) were reared under intensive management for 8 weeks. Weekly measurements included body weight and 8 linear body traits: BL, BG, DS, DC, SL, SC, WL and KL. At 8 weeks, liver tissues from 32 birds (8 males and 8 females per breed) were collected for RNA extraction and quantitative PCR analysis. Data were analyzed using analysis of variance, correlation and regression models. Ross 308 exhibited significantly (p < 0.001) higher body weight and superior linear measurements compared to FUNAAB Alpha, while males generally outperformed females at later ages. Relative expression analysis revealed higher TSHβ expression in Ross 308, whereas sex effects were minor. Correlation analysis indicated stronger associations of TSHβ expression with skeletal traits, particularly KL and DC, than with overall body weight. These results identify TSHβ as a candidate gene influencing skeletal development and growth efficiency in broilers and highlight its potential utility in marker-assisted selection strategies aimed at improving productivity, efficiency and profitability in poultry breeding programs.