The effect of feeding a mixed feed additives on greenhouse gases emissions from slurry pits

This study evaluated the impact of a feed additive mixture (comprising benzoic acid, saponin, prebiotics, and minerals at 0.5%) on greenhouse gas emissions during pig manure storage in laboratory-scale slurry pits.Compared to the control, the group fed with additives exhibited a higher average CO 2 emission rate (51.7±22.9g/day/m 3 -slurry vs. 29.4±2.9g/day/m 3 -slurry), though this difference was not statistically significant (p>0.05).However, the CO 2 emission reduction rate over time was steeper with the additive.For CH 4 , the average emission rate was 1.5±0.9kg/day/m 3 -slurry with the additive and 1.0±0.4kg/day/m 3 -slurry in the control, with no significant difference (p>0.05).While the additive group initially produced more CH 4 , this trend reversed later in the experiment.These findings suggest that the potential of feed additives to reduce CO 2 and CH 4 emissions may become more apparent over longer experimental periods.In contrast, N 2 O emissions were significantly lower with the additive (6.2±2.5 mg/day/m 3 -slurry) compared to the control (36.0±15.1 mg/day/m 3 -slurry), representing an approximately 81.7% reduction (p<0.05).This effect was most pronounced during the early stages of manure storage.Consequently, feed additives effectively mitigate N 2 O emissions early in the storage process.Given the relatively short study duration of 55 days, further research is warranted to assess greenhouse gas emissions over extended periods of pig manure storage.