Does light intensity affect the behavior, welfare, performance, meat quality, amino acid profile, and egg quality of Japanese quails?

The current study aimed to explore the impact of different light intensities on behavior, welfare, performance, meat quality, amino acid content, and egg quality of Japanese quails. A total of 600 1-day-old Japanese quail chicks were used (300/batch). Chicks were homogeneously classified into 3 groups (each of 100); low (10 lux), moderate (50 lux). and high light intensity (250 lux) groups. There was a significant effect (P < 0.05) of light intensity in most of the Japanese quails' behaviors. Quails reared on low light intensity showed the lowest behavior of feeding, drinking, flying, and feather picking, while the highest behaviors were preening, dust bathing, leg and wing stretching, and body shaking when compared with the other groups. Moreover, they had the better welfare (lowest H/L ratio and corticosterone levels). Quails of low light intensity groups possessed the heaviest body weight (145.17 g, P = 0.000) with the lowest daily feed intake (14.17 g) but with the best feed conversion ratio (3.39%, P = 0.000). Moreover, they had the heaviest slaughter (132.47 g, P = 0.000) and carcass weight (109.29 g, P = 0.000) and carcass yield (75.37%, P = 0.000) when compared with the others groups. Muscles of quails (both of pectoral and thigh) kept under low light intensity revealed the highest percentage of lightness, yellowness, and water-holding capacity with the lowest percentage of cooking loss, thiobarbituric acid reactive substances, and some amino acids. They also had the heaviest egg weight (11.24 g, P = 0.000) with the best external and internal egg-quality grades (P < 0.05). Consequently, low light intensity is suggested for improving quail's welfare, performance, and reproduction, while the high light intensity had a detrimental effect on both welfare and performance.