Effects of multi-phase nutritional programs associated with balanced digestible amino acid profiles on the productive...

Nutritional requirements of Japanese and European quails vary with genetic background, production phase, and production purpose, emphasizing the need to match nutrient supply with physiological demands. Multi-phase programs with balanced digestible amino acid profiles may improve nutrient utilization and productive efficiency. This study evaluated different nutritional programs for Japanese and European quails based on the recommendations of NRC (1994), Silva and Costa (2009), Rostagno et al. (2011, 2017, 2024), and commercial guidelines. A total of 1,800 quails were distributed into three experiments involving growing Japanese quails, laying Japanese quails, and growing European meat-type quails. In each experiment, six nutritional programs were evaluated, with 10 replicates of 10 birds per treatment. Performance, egg quality, feed efficiency, and carcass traits were evaluated according to the experimental phase and type of quail. Data were subjected to analysis of variance, and means were compared using Tukey's test at a 5% probability level (P < 0.05). In growing Japanese quails, the Rostagno et al. (2024) program resulted in the lowest feed intake (12.90 g/quail/day) and feed conversion ratio (3.37 g/g), representing reductions of 15.0% and 6.9%, respectively, compared with the highest values among treatments. In laying Japanese quails, the Rostagno et al. (2024) program resulted in the highest egg production (89.88%) and egg mass (9.51 g/quail/day), as well as the highest specific gravity (1.070 g/cm³) and eggshell percentage (8.90%). In European quails, the multi-phase program based on Rostagno et al. (2024) resulted in lower feed intake (17.3 g/quail/day), better feed conversion (2.6 g/g), and greater carcass yield (75.2%) than the NRC (1994) program. Overall, the Rostagno et al. (2024) program provided the most consistent improvements in feed efficiency across growing quails and enhanced productive performance and selected egg quality traits in laying Japanese quails. These findings highlight the importance of updating nutritional programs according to physiological stage, genetic potential, and productive purpose.