EFFECT OF DIETARY DL-ALPHA-TOCOPHEROL ON TISSUE ALPHA-TOCOPHEROL AND GAMMA-TOCOPHEROL AND PULMONARY-HYPERTENSION SYNDROME (ASCITES) IN BROILERS

The objectives of this experiment were to determine the effects of hig h dietary levels of vitamin E on growth performance and pulmonary hype rtension syndrome (PHS) mortality. Male broiler chicks (Cobb 500) were randomly assigned to one of four dietary treatments consisting of sta ndard starter and grower diets supplemented with 0, 17, 46, and 87 mg dl-alpha-tocopherol acetate/kg. To encourage the development of PHS, a ir temperature in the house was 32 and 28 C for Weeks 1 and 2, dropped to 18 C during Week 3, and kept between 10 and 15 C during Weeks 4 th rough 7. Also, chicks were placed in floor pens on Litter used for fiv e previous flocks and ventilation reduced to increase dust and ammonia in the house. Ammonia levels increased from an initial 18 to 36 ppm o n Day 42 with the increase in ammonia corresponding to an obvious incr ease in dust in the air. Lung and Liver tissue obtained at 2, 5, and 7 wk of age were analyzed for tissue alpha- and gamma-tocopherol by liq uid chromatography. Dietary vitamin E had no effect on body weight, fe ed intake, or feed efficiency. Cumulative PHS mortality through 7 wk o f age was 21% and was also unaffected by dietary treatment. Liver and lung alpha-tocopherol concentrations exhibited a dose-response increas e to dietary tocopherol and there was a high correlation between lung and liver tissue alpha-tocopherol (r = 0.72, P < 0.05). Whereas gamma- tocopherol concentrations in lung and liver were unaffected by dietary treatment, lister and lung exhibited age-dependent increases in both alpha- and gamma-tocopherol. Despite dose-dependent increases in tissu e alpha-tocopherol, supplementation of diets with up to 87 mg dl-alpha -tocopherol acetate had no effect on growth performance or PHS mortali ty in broilers under the conditions used in this study.