PSVI-4 - Effect of zinc source fed at nutritional levels on finishing pig growth performance and carcass characteristics

Abstract: A total of 2,363 pigs (PIC 337 × 1050; initially 26.9 ± 0.28 kg) were used in a 122-d study to determine the effects of four Zn sources on growth performance and carcass characteristics of finishing pigs under commercial conditions. Pigs were housed in mixed-sex pens with 26 or 27 pigs per pen and 22 pens per treatment. The four dietary treatments were arranged in a randomized complete block design and consisted of four Zn sources, all added at 100 mg/kg. The Zn sources included ZnSO₄, two sources of Zn Hydroxychloride (Source A = Hydroxy Zn, SAM Nutrition, Bloomington, MN; source B = Intellibond Z, Selko, Indianapolis, IN), and a chelated Zn (B-Traxim 2C Zn-260, Pancosma, Rolle, Switzerland). The Zn was included in diets via inclusion in four separate VTM premixes and each acted as the sole source of Zn supplementation in the diet. Corn-soybean meal-DDGS (20% in phases 1 to 3 and none in phase 4) based diets fed in mash form were used in a four-phase feeding program with all diets formulated to meet or exceed the NRC (2012) nutritional requirement for each phase. The 3 heaviest pigs per pen were marketed when the average weight of the barn was approximately 109 kg, with remaining pigs marketed approximately 25 d later. On the last day of the experiment, pigs were weighed, tattooed on a pen basis, and sent to a commercial packing plant to determine carcass composition and yield. No differences (P > 0.10) between Zn sources were observed for growth performance, mortality, removals, total removals and mortality, HCW, carcass yield, and loin depth. A marginal response was observed for backfat depth (P = 0.095) and percentage lean (P = 0.072). However, it did not result in a means separation. In conclusion, the Zn source did not significantly affect finishing pig growth performance or carcass characteristics, except for a marginal difference between Zn sources for backfat and percentage lean.