The histological and pathological changes of liver and testis of Japanese quails fed different levels of dietary L-valine

Abstract

Abstract While the roles of dietary L-valine (VAL) in body weight gain were reported, reinforcing roles of this BCAA in oxidative stress and the side effects in sensitive organs such as liver and testis is an undertreated issue. This experiment was carried out to investigate the histological changes of liver and testis of Japanese quail fed different levels of dietary VAL. Japanese quail chicks (male and female) were used in a completely randomized design with five experimental groups (five levels of VAL), for 42 days. Experimental diets including 0.75 (Control), 0.85, 0.95, 1.05 and 1.15%VAL in diet were formulated to be isoenergetic and isonitrogenous to meet nutrients recommendation of growing quails. At 42 d of age, quails were slaughtered and tissue samples were collected and fixed to evaluate the histological indices of liver and testis. Increase of VAL in low protein diet (17% crude protein (CP)), increased diameter of liver cell nucleus and liver hepatocytes (P < 0.01) in both male and female. Bile duct hyperplasia was observed in treatment 1.05% VAL, and treatment 1.15% VAL showed mild hepatosteatosis. In 0.75% and 0.85% VAL groups, there was no negative effects on the liver histology. The level of 0.85% VAL in the diet improved reproductive indexes in male (Tubular differentiation index (TDI) and spermatic index (SI); P < 0.05). In conclusion, the use of high levels of VAL (more than 0.85%) in a low protein diet during at 1–42 d of age can lead to histological damage in the liver and testis of quails.