358 Effects of fermented feed supplementation on pig growth performance: A meta-analysis

Abstract Fermented feed (FF) is recommended due to its high nutritional value and digestibility, but its effects on pig growth performance are inconsistent. This meta-analysis was conducted to quantify the effects of FF on pig growth performance. We systematically searched in PubMed and Web of Science for studies (published between January 1, 2000 and December 20, 2018) comparing the effects of FF supplementation with basal diet on the pig growth performance. The main outcomes were average daily gain (ADG), average daily feed intake (ADFI), and gain: feed ratio (G/F). Random-effects model was used to compute the weighted mean difference (WMD) and 95% confidence interval (95% CI). The robustness of the pooled estimates was determined using sensitivity and subgroup analyses. Of 1371 identified articles, 25 were eligible and were included in the meta-analysis (n = 2391 pigs). Compared with the basal diet, FF supplementation improved ADG and G/F of weaned piglets (ADG: WMD = 18.698 g/d, 95% CI: 13.925 to 23.472, P < 0.001; G/F: WMD= 0.027, 95% CI: 0.020 to 0.036, P < 0.001), growing pigs (ADG: WMD =24.436 g/d, 95% CI: 12.441 to 36.430, P < 0.001; G/F: WMD = 0.011, 95% CI: 0.003 to 0.021, P = 0.004), and finishing pigs (ADG: WMD = 42.012 g/d, 95% CI: 8.799 to 75.226, P = 0.015; G/F: WMD = 0.018, 95% CI: 0.004 to 0.032, P = 0.014), but had no effect on ADFI (P > 0.05). The subgroup analyses revealed that fermented feed ingredients could boost the growth performance of weaned piglets and growing pigs. Moreover, the fermented feed additives promoted growth at all stages. Our study supports FF can enhance pig growth performance. To our knowledge, this is the first meta-analysis on the topic to provide production strategies for FF application in pig industry.