Adverse effect of dietary vanadium, contributed by dicalcium phosphate, on albumen quality

Two experiments were conducted to determine the effects of dietary vanadium (V) on egg albumen quality. In Experiment 1, White Leghorn hens fed 9.9 ppm V supplied from a commercial dicalcium phosphate (Dical B at 1.5% of the diet) or a diet containing 29.9 ppm V (28.5 ppm from ammonium vanadate and 1.4 ppm from Dical A) produced eggs with significantly poorer albumen quality (61.7 and 61.6 Haugh units, respectively) than those of hens fed 1.4 ppm V from Dical A (76.9 Haugh units). The decline in albumen quality occurred within 1 week of treatment and persisted through 4 weeks of V feeding. Inclusion of 28.5 ppm V as ammonium vanadate also reduced egg production and feed consumption but had no significant effect on egg weight or change in body weight during the 4-week test period. At the end of 4 weeks, all hens were fed the 1.4-ppm V diet. Improvement in albumen quality was observed within 1 week, and after 4 weeks of the recovery period, no significant differences among treatment groups were observed. Part 1 of Experiment 2 showed that albumen quality was significantly reduced by 6.0 and 7.9 ppm V, supplied from Dical B, but 2.0 or 4.0 ppm V did not significantly change albumen quality during a 4-week trial. In Part 2 of Experiment 2, the inclusion of 9.9 ppm V from Dical B again significantly reduced albumen quality within 1 week. The magnitudes of adverse effects of 6.0, 7.9, and 9.9 ppm V on albumen quality plateaued approximately 4 weeks after treatment began and remained relatively constant through 6 weeks of feeding 9.9 ppm V and through 10 weeks of feeding 6.0 or 7.9 ppm V. The results demonstrate that certain commercial dicalcium phosphates may contribute excessive V to the diet of hens, and, when present at levels of 6.0 ppm or more, V will adversely affect albumen quality.