Influence of protein fermentation and carbohydrate source on in vitro methane production

Abstract

Previous studies have shown the influence of donors? diet on in vitro rumen fermentation. Batch cultures of rumen microorganisms were used to investigate the influence of the donor sheep diet (medium- versus high-concentrate) on fermentation of sunflower seed (SS) and meal (SM) treated with malic acid and heat (MAH; 150ºC for 1 h) to protect the sunflower protein from degradation, and to compare the effects of MAH treatment with those produced by supplementing the same amount of malate, either as free acid (MA) or as disodium malate (DSM), as a feed additive.. In 16.5 h incubations, the MAH treatment reduced CH4 production and ammonia-N concentrations for SS (60.3 and 45.3%, respectively) and SM (23.7 and 17.2%), but for SS the organic matter fermented was also reduced by 14.8%. Adding the same amount of malic acid as additive did not affect (P =0.05) CH4 production for any feed, but reduced ammonia-N concentrations by 13.8% for SM. For some fermentation parameters, the response to MAH treatment was more pronounced by using fluid from sheep fed the high-concentrate diet. There were differences between SS and SM in the response to MA and DSM supplementation.