EFFECTS OF DIET COMPOSITION ON VANADIUM TOXICITY IN LAYING HENS

V added to laying rations as NH4 VO3, VOCl2 or VOSO4 at levels of 20-80 ppm resulted in a rapid and substantial reduction in albumen quality as measured by Haugh units. Dietary V reduced egg production, egg weight, body weight, feed consumption and shell quality as measured by specific gravity. Ascorbic acid at 0.4-0.5% effectively protected the hen from reduction in albumen quality, egg production, and body weight for up to 40 ppm V, but not reduction of egg weight. Replacement of soybean meal by 20% dietary cottonseed meal also protected the hen from reduction in albumen quality, egg production and body weight for up to 40 ppm V. Added at levels of 4- to 8-fold the molecular concentration of V, EDTA had no consistent effect on V toxicity. Dehydrated grass, at levels of 6-12%, maintained egg production but had no effects on reduction in albumen quality caused by 40 ppm V. Replacement of soybean meal with herring fish meal and part of the grain with sucrose intensified the depression of albumen quality, egg production and loss of body weight caused by added V. Varying dietary protein levels from 12 to 25% using soybean meal or the addition of 20 ppm Cr had no effect on toxicity of added V. V expressed its toxicity in laying hens by several routes since the protective effects of different dietary changes and additives differentially affected the loss of albumen quality, egg production, body weight and egg weight.