Olla A Khalifa, Seham F Shehata, Marwa I Abdel-Haleem, Maha Mamdouh, Samar H Baloza
This study assessed the impact of a methyl donor precursor (methionine) and an essential oil (turmeric oil), either individually or combined, on growth performance, economic efficiency, serum biochemistry, intestinal histomorphometry, and related gene expression in broiler chickens. A total of 200 one-day-old male Hubbard chicks were randomly assigned to four experimental groups (5 replicates/group, 10 birds/replicate): control, methionine, turmeric oil, and combined. Quantitative reverse transcription polymerase chain reaction (qRT-PCR) was employed to evaluate the relative mRNA levels of appetite-related genes (leptin and cholecystokinin (CCK)), plus growth-related genes (growth hormone receptor (GHR), and insulin like growth factor (IGF-1)). The results indicated that dietary supplementation with either methionine or turmeric oil, when applied separately, enhanced body weight gain, decreased feed conversion ratio (FCR), and improved economic efficiency, including total return and net profit across treatments. Concurrently, it significantly affected intestinal histomorphometry by increasing villus height, crypt depth, and goblet cell density across the small-intestinal segments (P < 0.001). The combined group had the highest duodenal VH/CD ratio, which was significantly higher than that of the methionine group (P = 0.026). At the molecular level, numerical alterations were induced in target genes, including the upregulation of GHR and Leptin expressions, alongside a reduction in CCK expression. Notably, a significant upregulation (P < 0.05) was observed in IGF-1 expression, which showed the most pronounced response, coinciding with enhanced growth performance. In summary, the incorporation of a methyl donor precursor (methionine) and/or essential oil (turmeric oil) in broiler feed markedly improved performance, health, and economic viability and was associated with changes in appetite- and growth-related gene expression.