Influence of Dietary Supplementation of Ensiled Devil Fish and Staphylococcus saprophyticus on Equine Fecal Greenhouse Gases Production

The present context was designed to investigate the efficacy of devil fish (DF; Plecostomus sp.) silage and Staphylococcus saprophyticus on fermentation characteristics as well as greenhouse gases production mitigation attributes in horses. Four levels of ensiled DF at 0 (control DF0), 6 (DF6), 12 (DF12), and 18 (DF18) % were added into the diet. Moreover, three doses of S. saprophyticus (0, 1, and 3 mL/g dry matter [DM]) were used for in vitro fecal fermentation. The use of ensiled DF resulted in increased (P < .0001) pH during fermentation. The asymptotic gas production was the highest (P < .0001) in DF6, whereas other supplementation caused lower production than that of control. Lag time for the asymptotic gas production decreased (P < .05) with increasing dietary DF doses. Inclusion of S. saprophyticus resulted in the lowest (P < .05) gas production and mL/0.5 g DM incubated and thus, the reduced gas production up to 23.17% than that of control. The interaction of DF × S. saprophyticus showed the lowest gas production at DF18, whereas the highest production was estimated at DF6 without S. saprophyticus after 48 hours. The lowest emission of CO2 (P < .0001) was observed in DF18 inclusion, which was 15.25% lower than that of control at 48 hours of fermentation. In contrast, the lowest hydrogen (H2) production was estimated in DF0, whereas DF18 exhibited the highest. Inclusion of DF12 and DF18 reduced (P < .05) methane (CH4) emission by 58.24% and 59.33%, respectively. However, DF, S. saprophyticus, and DF × S. saprophyticus interaction had no significant effect (P > .05) on CH4 production. In conclusion, ensiled DF and S. saprophyticus could be supplemented in equine diet as promising alternatives to corn for mitigating the emission of greenhouse gases effectively. •Methane production was reduced from 58.24% to 59.33% because of devil fish supplementation.•Supplementation of devil fish reduced CO2 production by 15.25%.•Staphylococcus saprophyticus mitigated CH4 production up to 58.24%.•Dietary inclusion of 6% devil fish improved total gas production.•Devil fish inclusion at varied doses led to increase the horse fecal pH.