Weaning-to-finishing pigs face challenges related to gut health, growth performance, and environmental sustainability. Dietary ZnO and probiotic supplementation may provide a nutritional strategy to support productivity while reducing the need for high ZnO levels.
Objective: The study aimed to assess the effects of dietary zinc oxide (ZnO) combined with probiotic supplementation on growth performance, fecal characteristics, meat quality, and noxious gas emissions in weaning-to-finishing pigs.
Methods: A total of 200 weaned pigs (body weight of 6.65 ± 0.66 kg) were randomly assigned to four dietary treatments with ten replicates per treatment. The dietary treatments were: TRT1, basal diet + ZnO 75 ppm; TRT2, basal diet + ZnO 75 ppm + probiotics (0.3% initially and 0.1% thereafter); TRT3, basal diet + ZnO 2500 ppm initially and 75 ppm during finishing; and TRT4, basal diet + ZnO 2500 ppm + probiotics (0.3% initially and 0.1% thereafter). Growth performance, fecal index, noxious gas emissions, microbiota composition, and meat quality were measured.
Results: Probiotic-supplemented groups (TRT2 and TRT4) exhibited higher body weight and average daily gain at weeks 18 and 22, as well as increased average daily feed intake throughout the experimental period compared with TRT1 and TRT3. Additionally, these groups showed reduced ammonia and hydrogen sulfide emissions during the later stages of production. No differences were observed in fecal scores or meat quality parameters among treatments. However, ZnO supplementation combined with probiotics improved gut microbiota diversity, including alpha and beta diversity indices, increased the abundance of beneficial bacterial groups such as Firmicutes, Prevotella, and Lactobacillus, and reduced potentially pathogenic bacteria, including Clostridium sensu stricto 1.
Conclusion: The results indicate that combining probiotics with reduced ZnO levels improves growth performance, modulates gut microbial composition, and contributes to environmental sustainability by reducing noxious gas emissions, these findings support probiotic supplementation as a nutritional strategy to decrease dependence on high-dose ZnO while enhancing production efficiency in pigs.
Biswas S, Kim MH, Cho S, Kim IH. Impact of zinc oxide levels and probiotic supplementation in weaning-to-finishing pig diets: productivity, gut microbial composition, and environmental implications. Journal of Animal Science and Technology. 2026; 68(3): 814-840. https://doi.org/10.5187/jast.2025.e33