Responses of weanling pigs to dietary supplementation with vitamin C or carbadox.

A 2 X 2 factorial arrangement with two levels (0, 660 ppm) of vitamin C and two levels (0, 55 ppm) of carbadox supplementation was used in two experiments with 112 crossbred pigs weaned between 4 and 5 wk of age. An 18% protein corn-soybean meal-oats-dried whey starter diet was used as the basal diet. Each diet was fed ad libitum for a 4-wk period to three replicates of four pigs in Exp. 1 and to four replicates of four pigs in Exp. 2. Vitamin C supplementation produced a significantly higher plasma vitamin C concentration in weanling pigs, but, contrary to results of our previous study, failed to improve average daily gain of the pigs. Daily gain was, however, improved significantly by carbadox supplementation. Carbadox also produced a significantly higher plasma vitamin C concentration in pigs after a 7-d lag period. Plasma Fe concentration of pigs was not affected by supplemental vitamin C, but was significantly higher in those fed carbadox-supplemented diets. Plasma ceruloplasmin concentration increased significantly in all treatment groups from the initial sampling period (d 0) to subsequent periods. No interactions between supplemental vitamin C and carbadox were observed in daily gain, feed efficiency and the measured plasma constituents.