Influence of Kappaphycus Alvarezii and Gracilaria Salicornia Supplementation on in Vitro Fermentation Pattern, Total Gas and Methane Production of Mixed Substrates

Abstract

\n This experiment was conducted to study the effect of supplementation of Kappaphycus alvarezii (KA) and Gracilaria salicornia (GS) in vitro fermentation pattern, total gas and methane production of mixed substrates. Basal substrate comprising of concentrates and wheat straw (50:50) was supplemented with either 0% (control), 1 (KA1), 2 (KA2), 4 (KA4), 6 (KA6), and 8 % (KA8) of Kappaphycus; and, 1 (GS1), 2 (GS2), 4 (GS4), 6 (GS6), and 8 (GS8 ) of Gracilaria, respectively. Asymptote, rate constant of gas production and t-half, concentration of total volatile fatty acids (TVFA), and in vitro dry matter digestibility (IVDMD) was not affected up to 2% level KA supplementation, beyond which asymptote, and rate constant of gas production, TVFA, and IVDMD decreased and t-half increased (P<0.001). Asymptote, rate constant of gas production, TVFA and IVDMD was not affected at 1% level of inclusion, beyond which a steady decline in these parameters was observed (P<0.001). Methane production (ml/g DM) was higher (P<0.001) in CON, followed by KA1 and KA2, and lower values were observed in by KA4, KA6 and KA8. Methane production (ml/kg DM) declined (P<0.001) steadily with increased level of GS in the substrates. From the results it was concluded that inclusion of Kappaphycus alvarezii and Gracilaria salicornia at 2 and 1%, respectively in the fermentation substrate can reduce in vitro methane production without any adverse impact on total gas production and in vitro dry matter digestibility.