This study evaluated the effects of chromium yeast (Cr yeast) and two apparent metabolizable energy (AME) levels on productive performance, egg quality, and lipid and carbohydrate metabolism in laying hens. A total of 192 Bovans White laying hens at 47 weeks of age were randomly assigned to eight dietary treatments (six replicates each) in a 4 × 2 factorial arrangement: four levels of supplemental Cr (0, 0.2, 0.4, and 0.8 ppm as Cr yeast) and two AME levels (2,780 [...] ABSTRACT This study evaluated the effects of chromium yeast (Cr yeast) and two apparent metabolizable energy (AME) levels on productive performance, egg quality, and lipid and carbohydrate metabolism in laying hens. A total of 192 Bovans White laying hens at 47 weeks of age were randomly assigned to eight dietary treatments (six replicates each) in a 4 × 2 factorial arrangement: four levels of supplemental Cr (0, 0.2, 0.4, and 0.8 ppm as Cr yeast) and two AME levels (2,780

With the growing demand for sustainable and cost-effective poultry production, optimizing nutrient utilization is crucial. Exogenous proteases enhance protein digestibility, reduce nitrogen excretion, and improve feed efficiency, but their interaction with additives like copper sulfate (CuSO₄) and formaldehyde remains unclear. This study evaluated the combined effects of protease with these additives on amino acid digestibility, performance, and bone quality in broilers. A total of 500 broilers were assigned to seven dietary treatments, each replicated 10 times (six birds per cage) over 21 days (14 days of adaptation and 7 days of evaluation). Treatments included a reference diet (RD), RD + CuSO₄ (600 g/ton, 150 mg Cu/kg), RD + formaldehyde (2000 g/ton), with or without protease supplementation (30,000 NFP/kg), and a protein-free diet. Protease improved protein digestibility (2.50%) and amino acid digestibility (essential: 2.64%; non-essential: 2.52%) in diets with CuSO₄ or formaldehyde (p < 0.05). CuSO₄ alone had no effect, but its combination with protease significantly enhanced crude protein digestibility (4.63%). Formaldehyde reduced amino acid digestibility, but protease mitigated this negative effect (−4.68% vs. −1.81%). Protease also improved feed conversion and bone strength. These findings demonstrate that protease combined with CuSO₄ or formaldehyde optimizes nutrient digestibility, enhances broiler performance, and supports sustainable poultry production.

This study aimed to assess the effects of environmental temperature and age of broilers on the energy value of corn. A total of 288 Cobb 500 chicks were distributed in a complete randomized design with a split-plot arrangement and six replications of six chicks each. The main plot consisted of three temperatures (cold: 18 ºC; thermoneutral: 25 ºC; and hot: 33 ºC), while the secondary plot consisted of age (initial: 11 to 14 days; growing: 25 to 28 days; and final: 39 to 42 days). The basal diet was based on corn and soybean meal. The test diet was produced by replacing the basal diet for test food: 40% corn + 60% basal diet. The mean values of AMEn observed for broiler chicks under cold, thermoneutral, and hot temperatures were 3322, 3279, and 3233 kcal/kg of natural matter, respectively, and 3215, 3218, and 3400 kcal/ kg of natural matter for the initial, growing, and final phases, respectively. Overall, the metabolizable energy values of corn and the balance and coefficients of metabolizability of nutrients in the test diet increased with the broiler age, but the true metabolizable energies of corn were not affected by environmental temperature. The balance and coefficients of metabolizability of nutrients in the test diet decreased due to heat exposure during the growing and final phases.