LAUSR

ABSTRACT The purpose of this study was to evaluate the effects of dietary metabolizable energy (ME) and digestible lysine (DLys) on the laying performance, egg quality, and economic profit of Japanese quails (Coturnix coturnix japonica) reared in a hot climate. Seven hundred eighty Japanese quails, 63 days old and weighing 149 ± 0.010 g, were used in a randomized experiment with 12 treatments, arranged in a 3 × 4 factorial design (ME levels of 2600, 2875 or 3150 kcal/kg; and DLys levels of 0.90, 1.05, 1.20 or 1.35%), five replicates per treatment and 13 birds per experimental unit. The 112 days of experimental period was divided into four 28-days laying cycles to determine performance and egg quality. The temperature and humidity index fluctuated daily between 82.02±2.76 to 72.65±1.13 There was an interaction between ME and DLys on metabolizable energy intake per gram of produced egg. Increasing dietary DLys levels increased linearly DLys intake (kcal/bird/day) and expenditure (mg/g of produced egg) without affecting laying performance and egg mass and quality. Quails fed with dietary 2875 or 3150 kcal/kg adjusted voluntary feed intake to maintain similar ME intake and, as a consequence, had similar percentage of posture, egg mass, viable eggs for sale, egg weight, and economic return. In contrast, these variable responses were lower for those fed with dietary 2600 kcal/kg. Dietary 3150 kcal/kg ME showed the highest responses (P