Influence of Acetic Acid–Based Feed Formulation on Energy and Protein Metabolizability and Growth Performance in Rhode Island Red Chickens (Gallus gallus domesticus)

The search for alternatives to antibiotic growth promoters in poultry has intensified due to concerns about antimicrobial resistance and food safety. Organic acids, particularly acetic acid, have shown potential in improving gut health, nutrient absorption, and growth performance. This study evaluated the effects of acetic acid–based feed on energy and protein metabolizability, growth performance, and production efficiency in Rhode Island Red chickens (Gallus gallus domesticus). Ninety-six one-week-old chicks were randomly assigned to four dietary treatments in a randomized complete block design: T0 (control, 0% AA), T1 (0.3% AA), T2 (1.65% AA), and T3 (3% AA). Home-mixed starter and grower rations were formulated using Brill Feed Formulation Software and fed ad libitum for ten weeks. Growth performance parameters (BW, ADG, WG, FCR, VFI) were measured, while true metabolizable energy (TME) and true metabolizable protein (TMP) were determined using a force-feeding procedure. Data were analyzed using ANOVA and Tukey’s HSD (p<0.05). No significant differences were observed among treatments for growth performance, TME, or TMP. However, T3 numerically exhibited higher BW, WG, and ADG, and lower FCR. Economically, T3 and T2 had the lowest cost-to-produce (CTP), which was significantly lower than T0 and T1 (p<0.05). Although improvements in growth and nutrient utilization were not statistically significant, the consistent numerical trends in T3 suggest a potential benefit of acetic acid inclusion. These results indicate that acetic acid supplementation may enhance economic efficiency without compromising growth performance, supporting its use in sustainable and cost-effective heritage chicken production systems.