The effect of reduction or removal of dietary vitamin supplement on broiler chickens performance

Extract

While vitamins naturally occurring in plant and animal based feed ingredients can supply a reasonable proportion of the birds daily needs, their contribution is rarely considered during formulation. This situation arises due to variability, especially in cereals and vegetable proteins, for example, the vitamin E content of corn can vary from 10 to 40 IU/kg. Because of this uncertainty in the natural supply of vitamins within a feed, the bird’s vitamin supply is therefore met by the addition of synthetic vitamins, usually in the form of a so called premix, that contains all vitamins and perhaps some other micronutrients and feed additives. This premixes use according to producer suggestions and in some cases their doses can be higher than real requirements. Skinner et al (1992) removed vitamin premixes from 21 day of age and did not report any adverse effects. Gwyther et al (1992) showed sever performance reduction by vitamin premix withdrawal from 21 to 49 day of age. This experiment was conducted to determine the effects of Vitamin supplement levels on broiler chickens from 28 to 49 days of age.