Study on the Metabolic Implication of Supplemental Tryptophan in Exposed to Stress Chickens

MONEVA, P., S. POPOVA-RALCHEVA, D. GUDEV, V. SREDKOVA and I. YANCHEV, 2008. Study on the metabolic implication of supplemental tryptophan in exposed to stress chickens. Bulg. J. Agric. Sci., 14: 424-431 The effect of supplemental tryptophan (5g/1Kg-1 diet) on some indices of stress, heterophil-to-lymphocyte ratios (H:L), leukocyte and erythrocyte numbers in chickens under stress induced by alternating periods of normal feeding with periods of feed and water withdrawal was investigated. Twenty chickens at the age of six weeks were randomly allocated into two groupscontrol and experimental. Experimental birds were deprived of feed and water and their legs tied for seventeen hours each day in four consecutive days. Body weight was registered on d 0 (baseline value), d 7 (preliminary period-free of stress) and on d 11 (experimental period). Blood samples were taken on d 0 and d 11. Relative weights of some immunobiological organs were also measured at the end of the experimental period. Supplemental tryptophan alleviated body weight decline, decreased spleen (P>0.05) and liver (P<0.05) relative weights, but had no significant effect on those of adrenal glands and bursa of Fabricius. Plasma urea levels were not influenced by supplemental tryptophan but plasma glucose levels declined by 14h and cholesterol levels by 17h in comparison with control group. Tryptophan supplementation prevented H: L ratio increment caused by stressor treatment. Leukocyte numbers and hematocrit values were not significantly influenced by tryptophan. Interleukin-1α response to stress declined in triptophan supplemented chickens by 14 h following the start of stressor treatment but corticosterone response was not influenced. Our results indicate that tryptophan is implicated in white blood cells dynamics and influences the pattern of the observed stress indices in chickens.