In vitro Fermentation, Digestion Kinetics and Methane Production of Oilseed Press Cakes from Biodiesel Production

Following the extraction of oil for biodiesel production, oilseed press cakes are high in fat. As the dietary supplementation of fat is currently considered the most promising strategy of consistently depressing methanogenesis, it follows that oilseed press cakes may have a similar potential for CH4 abatement. As such, this study aimed to characterise the nutritive value of several oilseed press cakes, glycerine and soybean meal (SBM) and to examine their effects on in vitro ruminal fermentation, digestion kinetics and CH4 production. Moringa press oil seeds exhibited the greatest in sacco effective degradability (ED) of DM and CP (p<0.05). In vitro gas production (ml/g digested DM) was not affected (p = 0.70) by supplement at 48 h of incubation. In vitro DMD was increased with the supplementation of glycerine and SBM at all levels of inclusion. Moringa oilseed press cakes produced the lowest CH4 (mg/g digested DM) at 6 and 12 h of incubation (p<0.05). The findings suggest that moringa oilseed press cake at 400 g/kg DM has the greatest potential of the oilseed press cakes examined in this study, to reduce CH4 production, without adversely affecting nutrient degradability.