Effect of Dietary Lysine and Sex on Performance and Immunity Parameters of Japanese Quails

The present study was conducted to investigate the effects of dietary lysine (Lys) and sex on growing quail performance and immunity parameters. The six dietary Lys: 10, 11.5, 13.0 (NRC 1994 recommendation), 14.5, 16.0 and 17.5 gr/kg were provided. The other essential amino acids except lysine were provided to meet or exceed NRC 1994 recommendation for growing quail. This experiment was carried out in a complete randomized design arrangement from 3 to 24 days of age. Each treatment was consisted of 5 floor pens (50 quail chicks). Body weight (BW), body weight gain (BWG) increased significantly (P< 0.05) with dietary Lys supplementation up to 14.5 gr/kg Lys. The quails that consumed 14.5 gr/kg dietary Lys had the best feed conversion ratio (FCR). The carcass weight, breast weight and yield, thigh weight and yield, mortality and humoral immunity (response to sheep red blood cell) were significantly (P< 0.05) affected by dietary Lys. The breast yield, thigh weight and yield, white blood cells count, monocyte percentage and response to SRBC significantly (P < 0.05) influenced by sex. Neither age nor sex had any significant effect on lymphocyte percentage, heterophile percentage and heterophile to lymphocyte ratio at 24 d of age. In this study an interaction of sex with Lys were not significant (P > 0.05) for any traits. it concluded that optimum BW, BWG, FCR, immunity status at 24 day of age could be obtained with a 14.5 gr/kg Lys diet, so these level is more than, NRC 1994 recommendation. Furthermore, humeral immune system functions of quails were improved numerically by fortifying diets with Lys in excess of NRC 1994 recommendation, although it did not differ statistically with NRC 1994 recommendation level. Future research, however, should compare dietary Lys effects on immune system functions of quails reared in conventional environments or during an infectious challenge.