PSVI-21 Interactive effects of Zn sources, Cu sources and phytase on growth performance in nursery pigs

Abstract

This study investigated the interactive effects of Zn sources, Cu sources and phytase on growth performance in nursery pigs. A total of 288 weaning barrows (BW = 5.71 ± 0.81 kg), blocked by initial body weight, were randomly allotted to 1 of 8 dietary treatments, with 9 pens per treatment and 4 pigs per pen. The 8 dietary treatments were arranged in 2 × 2 × 2 factorial design, with 2 Zn sources [2000 ppm Zn from ZnO during phase 1 (d 1 to 14) and 2 (d 15 to 28), and 100 ppm Zn from ZnO during phase 3 (d 29 to 42); 100 ppm Zn from Zn methionine hydroxy analogue chelate (Zn-MHAC, MINTREX^® Zn, Novus International Inc., St. Charles, MO) during phase 1 to 3], 2 Cu sources [150 ppm Cu from CuSO₄ or Cu-MHAC (MINTREX^® Cu) during phase 1, and 80 ppm Cu from CuSO₄ or Cu-MHAC during phase 2 and 3], and 2 phytase inclusion levels (0, 500 FTU/kg). Results showed that there were no differences (P > 0.10) between ZnO and Zn-MHAC groups in terms of growth performance during the entire nursery period. Compared with CuSO₄, Cu-MHAC tended to increase ADG (P = 0.07) and G:F (P = 0.08) during the entire nursery period. There tended to be an interaction (P = 0.09) between Cu sources and phytase on G:F during phase 2. Specifically, without phytase supplementation, there was no difference (P = 0.63) on G:F during phase 2 between Cu-MHAC and CuSO₄, whereas with phytase supplementation, Cu-MHAC increased G:F during phase 2 (P = 0.05) compared with CuSO4. In conclusion, Zn-MHAC supplementation at 100 ppm could replace pharmacological level of ZnO without affecting growth performance. Cu-MHAC could improve growth performance compared with CuSO4. Cu-MHAC exerted synergistic effect with phytase on improving feed efficiency.