The efficacy of vitamin E (DL-alpha-tocopheryl acetate) supplementation in hen diets to alleviate egg quality deterioration associated with high temperature exposure
2001
Kirunda, D.F.K. | Scheideler, S.E. | McKee, S.R.
Supplementation of hen diets with vitamin E was investigated as a means to alleviate egg quality deterioration associated with high temperature exposure. One hundred eighty layers (60 birds/diet) were randomly placed on diets supplemented with vitamin E at 20, 60, and 120 IU/kg feed. After 2 wk on feed, one-half of the birds were maintained at environmental temperatures of 21 C, whereas the other half were acclimated over 3 d to increasing environmental temperatures reaching 34 C. Birds were exposed to 21 or 34 C for 2 wk (five hens per cage x six replications). Egg production, feed intake, and egg weights were determined daily. Twenty eggs were collected from each treatment group and analyzed for vitamin E content in yolk, percentage egg solids, yolk color, yolk pH, albumen pH, foaming ability of albumen proteins, emulsification capacity of yolk, yolk viscosity, yolk color, and vitelline membrane strength (VMS). Results suggested that high temperature exposure (HTE) caused a reduction in feed intake, egg production, Haugh units, egg weights, VMS, yolk and albumen solids, foam stability, angel cake volume, yolk color, and emulsification capacity. Supplementation of HTE hen diets with 60 IU vitamin E/kg feed improved feed intake, egg production, VMS, yolk and albumen solids, foam stability, and angel cake volume. However, egg weight, emulsification capacity, yolk color, yolk index, and yolk viscosity were not improved by vitamin E supplementation of HTE hens. Vitamin E levels in the yolk were lower from HTE hens compared with controls at all levels of vitamin E supplementation.
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