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Abstract The application of microencapsulation technology to protect zinc may support inclusion of reduced levels with similar benefits to elevated doses of free zinc oxide. This study aimed to compare the effects of different doses of a microencapsulated ZnO (Zinco-Plus S) and free ZnO in nursery diets on growth performance and intestinal health of pigs. A total of 480 newly weaned piglets 26 d of age, initial body weight (BW) = 7.39 kg were randomly assigned to one of four dietary treatments for 35d. Treatments were as follow: free ZnO (3,000, 1,500, and 0 ppm at phase 1, 2, and 3, respectively) or one of three doses of the microencapsulated ZnO (400, 600, and 800 ppm) maintained consistently across all 3 nursery phases (total amount of zinc in diets were within limits allowed by Canadian regulation). Each dietary treatment had 10 replicates, with 12 pigs/pen, gender balanced. All treatments had protease (Jefo Protease; 125 g/t), xylanase (Belfeed Xylanase; 100 g/t) and protected organic acids and essential oils (Porcinat+; 2 kg/t in phase 1 and 2, 1 kg/t in phase 3). Body weight, BW gain and feed intake were measured to determine feed conversion. At the end of phase 1, fecal sample was collected (pooled of 4 samples/pen) to determine zinc excretion. At the end of phase 2, blood serum was collected (1 pig/pen) to measure calprotectin and diamine oxidase concentrations and, ileal tissue was collected (1 pig/pen) to measure expression of zonular occludens (ZO) -1. Data were submitted to ANOVA and Fisher test with significance set at P 0.05. There was no difference (P 0.05) in final BW of pigs across all treatments. Nonetheless, piglets receiving 800 ppm of the microencapsulated ZnO had improved (P 0.05) feed conversion ratio compared with pigs fed diet containing free ZnO. There was no difference (P 0.05) in serum concentrations of calprotectin and diamine oxidase across all treatments, indicating improved intestinal health regardless of the form of ZnO. Piglets supplemented with microencapsulated ZnO at 800 ppm had an increased (P 0.05) intestinal expression of ZO-1 in comparison with piglets receiving free ZnO, indicating better intestinal integrity. Fecal zinc concentrations were reduced (P 0.05) by 75 % with the inclusion of microencapsulated ZnO compared with free ZnO. Piglets supplemented with microencapsulated ZnO at 800 ppm improved (P 0.05) feed cost per kg BW gain by 10.7 % when compared with free ZnO. These findings show that supplementing lower levels of zinc in nursery diets via microencapsulation technology improves growth performance and supports intestinal health at levels comparable with increased free ZnO supplementation. Moreover, the utilization of microencapsulated zinc oxide has the additional advantage of minimizing environmental impact through the reduction of zinc wastage.
Babatunde et al. (Sun,) studied this question.