Polyphenols as a partial replacement for vitamin E in nursery pig diets

A total of 300 pigs (241 × 600; DNA, Columbus, NE; initially 6.0 ± 0.01 kg) were used in a 42-d trial to determine the effects of vitamin E levels and partially replacing vitamin E with a polyphenol (Cabanin CSD, R2 Argo, Denmark) on growth performance, complete blood count, serum thiobarbituric acid reactive substances (TBARS), superoxide dismutase (SOD), and cytokine panel. Sixty pens of pigs were weighed and allotted to one of the five dietary treatments in a completely randomized design with 12 pens per treatment. A control treatment was formulated to provide 15 IU/kg of vitamin E equivalence from vitamin E. This control treatment was then used as a base for three replacement strategy diets to determine the effects of replacing an additional 60 IU/kg of vitamin E with polyphenol in diets containing a basal level of vitamin E requirement estimate (15 IU/kg). First, an additional 60 IU/kg of vitamin E was added for a total of 75 IU/kg of vitamin E equivalence. Second, 50% of the additional vitamin E (30 IU/kg) was replaced with the equivalency of polyphenol. Third, all 60 IU/kg of the additional vitamin E was replaced with the equivalency of polyphenol. To evaluate whether there are negative effects of feeding nursery pigs a high level of polyphenol, a fifth treatment was formulated to provide 575 IU/kg of vitamin E equivalence with 75 IU/kg from vitamin E and 500 IU/kg from polyphenol. Whole blood and serum samples were collected on days 10 and 42, and pig weights and feed disappearance were measured on days 10, 21, 31, 38, and 42. For growth performance, increasing vitamin E equivalence tended to improve (quadratic, P < 0.10) gain-to-feed ratio (G:F) from days 10 to 21, and tended to improve (linear, P < 0.10) G:F from days 21 to 42 and 0 to 42. There was a vitamin E equivalence × day interaction (P = 0.050) for serum SOD activity. Increasing vitamin E equivalence increased (linear, P < 0.05) serum SOD activity on day 42 but not on days 10 (P > 0.10). For serum cytokines, there was no evidence of differences (P > 0.10) between treatments and vitamin E equivalence. Moreover, there was no evidence of differences (P > 0.10) in all response variables between the three replacement strategies throughout the entire periods. In summary, increasing vitamin E equivalence tended to improve G:F, which may be related to the improved SOD activity. Furthermore, polyphenol can effectively replace vitamin E provided above the vitamin E requirement to provide similar benefits from increasing vitamin E equivalence.