PSII-16 Comparative digestibility of polysaccharide-complexed zinc and zinc sulfate in diets for gestating and lactating sows

Abstract

Abstract We hypothesized that digestibility of a zinc polysaccharide complex (PSZn) is greater than zinc sulfate when sows consume high fiber diets containing dried distillers grains with solubles (DDGS). Gilts and sows (n = 32) were blocked according to parity and randomly assigned to one of four dietary treatments. Treatments were: 1) Control (ConZnSO4) – corn-soybean meal based diet + 100 ppm Zn from ZnSO4; 2) Control PSZn (ConPSZn) – corn-soybean meal based diet + 100 ppm Zn from PSZn; 3) DDGS/ZnSO4 – corn-soybean meal-40% DDGS gestation and 30% DDGS lactation diet, each containing 100 ppm Zn from ZnSO4; 4) DDGS/PSZn – corn-soybean meal-40% DDGS gestation and 30% DDGS lactation diet, each containing 100 ppm Zn from PSZn. Titanium dioxide was used as an indigestible marker to evaluate digestibility of nutrients and Zn. Quantitative urine collection was used to calculate retention of Zn in the four dietary treatments. The statistical model included fixed effects of diet, Zn source, and their interaction, and random effects of parity. Endogenous losses of Zn were estimated in sows fed a corn-soybean meal diet without added Zn. There were no differences in Zn concentrations of urine, plasma, colostrum, or milk samples among treatments at any time of the experiment (P > 0.05; data not shown). Gestating sows fed DDGS/PSZn had improved (P < 0.05) ATTD, TTTD, and overall retention of Zn compared to Control treatments (Table 1). Lactating sows consuming diets without DDGS and supplemented PSZn had the greatest (P < 0.05) ATTD, TTTD, and retention of Zn, which were opposite to responses observed in gestation. Furthermore, ATTD, TTTD, and Zn retention for lactating sows consuming DDGS/PSZn were less (P < 0.05) than all other treatments. Zinc digestibility of ZnSO4 and PSZn appears to be differentially influenced by stage of the reproductive cycle and presence of dietary fiber from DDGS.