The histopathological changes of liver and testis of Japanese quail chicks fed different levels of dietary L-valine.

This experiment was carried out to investigate the histological changes of liver and testis of Japanese quail fed different levels of dietary valine (Val) in low protein diet. A total of 1000 one-day-old Japanese quail chicks (mixed sex) were assigned to five experimental diets including diets containing 7.5, 8.5, 9.5, 10.5 and 11.5 g digestible (dig.) Val/kg diet in a completely randomized design, with 5 replicates of 40 quail chicks per pen. Experimental diets were formulated to be isoenergetic and isonitrogenous (170 g crude protein/kg) to meet nutrients recommendation of growing quails suggested by Brazilian tables. At d 42, quail chicks were slaughtered, and tissue samples were collected and fixed to evaluate the histological indices of liver and testis. High levels of Val, increased (P < 0.05) diameter of liver cell nucleus and liver hepatocytes in both male and female. While 11.5 g Val showed mild hepatosteatosis, bile duct hyperplasia was observed in 10.5 g Val. In 7.5 and 8.5 g Val groups, there was no negative effects on the liver histology. The male quail chicks which fed on diets containing 8.5 g Val had better significant (P < 0.05) reproductive indexes [Tubular differentiation (TDI) and spermatic index (SI)]. In conclusion, the use of high levels of Val (≥ 9.5 g dig. Val/kg diet) during d 0 - 42 of age can lead to histological damage in liver and testis of quail chicks.