High vitamin levels ameliorate negative effect of rapeseed meal in meat ducks by improving antioxidant activity

The purpose of this study was to test the hypothesis that a high level of a vitamin premix would prevent the deleterious effects of rapeseed meal (RSM) when added to the diet of Pekin meat ducks. A total of 674 fifteen-day-old ducks were randomly allocated to 6 treatments with 7 cages of 16 ducks each. Three diets were formulated that contained 5, 10, or 20% RSM to compensate for reducing levels of soybean meal. Each RSM level diet was then supplemented with either a low level (low) or a high level (high) of a vitamin premix providing a total of 6 experimental diets. Ducks were fed one of the 6 experimental diets (N = 7 pens per diet) from days 15 to 35 at which time they were euthanized. Ducks were analyzed for antioxidant activity, liver biochemistry, thyroid hormone levels, and liver and thyroid histopathology. Addition of the high vitamin premixes to the 5 or 10% RSM diets improved BW (P < 0.05), BW gain (BWG; P < 0.05), and feed to gain ratio (F/G; P < 0.05) compared to the low vitamin premix; however, neither vitamin premix level had effects on production variables of ducks fed the 20% RSM diet. The high vitamin premix level also improved antioxidant capacity as evidenced by increased (P < 0.05) serum and liver superoxide dismutase activities over that of the low vitamin premix diets. Furthermore, the high level of vitamin premix prevented liver and thyroid pathologies in diets that contain RSM compared to diets with the low vitamin premix. These results suggested that high vitamin premix could prevent the negative effects of a 5 or 10% RSM diet in ducks by improving antioxidative capacities and alleviating liver and thyroid damage.