Effects of dietary supplementation of modified zinc oxide on growth performance, nutrient digestibility, blood profiles, fecal microbial shedding and fecal score in weanling pigs

One hundred and forty piglets ((LandracexYorkshire)xDuroc, 21 day of age) with an initial weight of 6.50 +/- 0.71kg, were randomly allotted into four treatments to determine the effects of a modified form of zinc oxide (ZnO) on growth performance, nutrient digestibility, blood profiles, fecal microbial shedding and fecal score in weanling pigs. Dietary treatments were: (i) NC, negative control, basal diet containing zinc (Zn) from the premix; (ii) PC, positive control, basal diet containing Zn-free premix + 3000ppm ZnO; (iii) H1, basal diet containing Zn-free premix + 3000ppm ZnO (phase 1, days 1 to 14)/200ppm modified ZnO (phase 2, days 15 to 42); (iv) H2, basal diet containing Zn-free premix + 300ppm modified ZnO (phase 1)/200ppm modified ZnO (phase 2). During days 1 to 14, average daily gains (ADG) were higher (P=0.04) in PC, H1 and H2 groups than that in NC group. Overall, H1 treatment increased the ADG compared with NC (P=0.05). On day 14, the alkaline phosphatase and plasma Zn concentration were increased (P=0.01 and 0.04, respectively) in PC, H1 and H2 treatments compared with NC treatment. On days 14 and 42, the fecal Lactobacillus counts in NC group were lowest (P=0.01, P=0.04 respectively) among treatments. All supplemented groups showed lower (P=0.03) fecal score than NC treatment on days 21 and 28. In conclusion, dietary supplementation with modified ZnO increased growth rates and reduced fecal scores in weanling pig. Modified ZnO could be used as a substitute to ZnO as a growth promoter and reduce Zn excretion to the environment because of the lower dosage. [Correction added on 3 February 2015, after first online publication: the initial weight of 6.50 +/- 1.11 kg' has been replaced with 6.50 +/- 0.71 kg' in the abstract.]