Effects of vitamin E, age and sex on performance of Japanese quail. 1. Haematological indices and liver function

1. A trial was conducted to examine the effects of dietary vitamin E content, age and sex on haematological indices and liver enzymes of Japanese quails. A total of 800 1-d-old quail chicks were assigned at random into 4 equal groups and fed on starter and layer diets containing 0, 1, 5 or 10 times the NRC recommended supplements of vitamin E. No selenium was added to the basal deficient diets; the other diets were supplied with 0.2 mg selenium/kg diet. 2. The investigation covered the age span of 3 to 12 weeks in female and male birds. Blood samples were collected at 3-week intervals and tested for haematological indices (erythrocyte count; leucocyte count; susceptibility of erythrocytes to haemolysis; haemoglobin concentration (Hb); packed cell volume (PCV); and mean corpuscular volume (MCV)) and liver enzymes (aspartate transaminase, AST, and glutathione peroxidase, GSH-Px). 3. The significant differences between the 4 dietary treatments indicated that as the levels of selenium and/or vitamin E increased, the percentage of erythrocytes haemolysed and AST activity decreased, whereas Hb and GSH-Px concentrations increased. 4. Differences between age groups showed that older quails had higher erythrocyte susceptibility to haemolysis, higher AST levels and but lower erythrocyte count and PCV. 5. Females had lower erythrocyte haemolysis and higher Hb concentrations than males. 6. The interaction between dietary groups and age groups revealed that the differences between age groups were reduced as the level of selenium and/or vitamin E increased, leading to similar group means over the age period of study. 7. In conclusion, NRC recommended supplements of vitamin E (12 and 25 mg/kg diet) were not adequate. Doses equal to, at least, 5 times that recommended were advised to improve GSH-Px (index of antioxidant status) and Hb concentrations.