Concentration of vitamins in the 13 feed ingredients commonly used in pig diets

The concentration of vitamins was determined in 143 samples of 13 feed ingredients commonly used in pig diets. The ingredients included corn and four corn co-products (corn distillers dried grains with solubles (DDGS), corn gluten meal, corn germ meal and corn gluten feed), wheat and two wheat co-products (wheat bran and wheat shorts), and five oilseed meals (soybean meal, rapeseed meal, peanut meal, sunflower seed meal and cottonseed meal). For corn and corn co-products, the content of β-carotene in corn gluten meal (11.10 mg/kg) was much greater than that in corn (1.62 mg/kg) and other corn products (2.16, 0.36 or 0.56 mg/kg, P < 0.01), whereas the content of choline was the least (80.04 mg/kg) in corn, and corn gluten feed had the greatest concentration of choline (1525.18 mg/kg). The greatest concentration of vitamin E was in corn DDGS (39.24 mg/kg). The concentration of niacin in corn was much lower than that in its co-products (3.68 vs. 23.23, 29.42, 36.46 and 52.65 mg/kg, P < 0.01). The contents of β-carotene were very low in wheat, wheat co-products and oilseed meals. The concentration of most of vitamins were greatest in wheat bran and least in wheat except that wheat shorts contained lower choline niacin (P < 0.01). For oilseed meal, the content of vitamin E was much greater (P < 0.01) in rapeseed meal (8.66 mg/kg) and cottonseed meal (10.57 mg/kg) than that in soybean meal (2.42 mg/kg), peanut meal (0.67 mg/kg) and sunflower seed meal (1.04 mg/kg). The concentration of niacin was low in cottonseed meal (9.15 mg/kg), and greatest in sunflower seed meal (183.91 mg/kg). The rapeseed meal (2276.32 mg/kg) had the greatest concentration of choline, while sunflower seed meal had the least choline (399.96 mg/kg, P < 0.01). Compared numerically, corn and its co-products were rich in β-carotene and vitamin E and oilseed co-products were rich in choline. These results indicate that the variability in concentration of vitamins among feed ingredients is very great. Therefore, careful attention must be paid to the balance of vitamins when these ingredients are used in pig diets.