Composition of vitamin supplements in Spanish poultry diets

1. The composition of 106 vitamin supplements used in about 85% of the Spanish poultry production diets were studied. Vitamin supplements were grouped by production classes and, for broilers and pullets, also by feeding periods. 2. Four vitamins (niacin, alpha-tocopherol, pantothenic acid, and riboflavin) comprised over 87% of the vitamin supplements by weight (choline excluded), whereas alpha-tocopherol and retinol represented from 51% to 60% of the total vitamin cost. 3. The highest and lowest vitamin supplementation rates were for broilers in the starter and withdrawal periods (106 and 44 mg/kg, respectively) and the mean values for breeders, pullets and layers were 104, 58, and 48 mg/kg, respectively. 4. Supplements with higher vitamin contents showed less variability in their composition. Retinol, cholecalciferol, riboflavin and pantothenic acid showed the lowest variability within supplements (6% to 36% CV), whereas alpha-tocopherol, menadione, thiamin and biotin showed the highest (40% to 224% CV). 5. Vitamin supplementation rates were compared with requirements, taking into account the dietary contribution. In general, vitamin fortification exceeded the NRC recommendations, using a high safety margin for some vitamins such as vitamin A (from 2.6 to 7.8) and for some poultry classes such as breeders (3.2).