Abstract Growing environmental concerns and new regulations limiting the use of high levels of therapeutic zinc oxide (ZnO) in nursery pig diets have intensified the search for effective alternatives. Microencapsulation technology provides an avenue to maintain the performance benefits of ZnO while substantially reducing dietary inclusion and environmental loss. This study investigated the effects of different inclusion levels of a microencapsulated ZnO (Jefo P (ZnO) compared to conventional ZnO on zinc excretion, feed cost, gut health, and growth performance in nursery pigs. A total of 480 weaned piglets (26 days of age; initial BW = 7. 39 kg) were assigned to one of four dietary treatments for a 35-day period. The control diet contained free ZnO (3, 000, 1, 500, and 0 ppm for phases 1, 2, and 3, respectively), while the test diets provided microencapsulated ZnO at consistent levels of 400, 600, or 800 ppm across all phases. All diets complied with Canadian regulations and included protease (Jefo Protease, 125 g/t), xylanase (Belfeed Xylanase, 100 g/t), and a blend of microencapsulated organic acids and essential oils (Jefo P (OA+EO), 2 kg/t in phases 1–2; 1 kg/t in phase 3). Growth performance, feed efficiency, and intestinal health indicators were assessed. Fecal samples collected at the end of phase 1 were analyzed for zinc excretion, while blood and ileal tissue were sampled at the end of phase 2 to assess serum calprotectin, diamine oxidase, and zonular occludens-1 (ZO-1) gene expression. Data were analyzed using ANOVA and Fisher’s test (P 0. 05). Although dietary ZnO levels were considerably lower in the microencapsulated treatments, final body weight did not differ (P 0. 05) among treatments. Pigs supplemented with 800 ppm microencapsulated ZnO demonstrated improved (P 0. 05) feed conversion (1. 44 vs 1. 62) compared with those fed free ZnO. Fecal zinc excretion was reduced (P 0. 05) by 75% (0. 29 vs 1. 19%), reflecting lower environmental output. Relative to free ZnO, feed cost per kilogram of gain was also reduced (P 0. 05) by 10. 7% (0. 75 vs 0. 84) in pigs fed 800 ppm microencapsulated ZnO. Serum calprotectin and diamine oxidase levels were unaffected (P 0. 05), while ZO-1 expression in the ileum increased (P 0. 05) in pigs receiving 800 ppm microencapsulated ZnO compared with free ZnO, suggesting enhanced intestinal barrier function. In summary, microencapsulated ZnO effectively replaced pharmacological doses of free ZnO in nursery pig diets without compromising growth performance. Its inclusion improved feed efficiency, reduced zinc losses to the environment, and lowered feed costs. These results demonstrate that microencapsulated ZnO represents a viable and sustainable solution for maintaining nursery pig productivity under current zinc use restrictions.
Babatunde et al. (Wed,) studied this question.
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