In vitro Evaluation of Calcium Nitrate and a Blend of Plants Containing Secondary Metabolites for their Impact on Methanogenesis and Feed Fermentation

Abstract

Two blends of plant parts containing plant secondary metabolites; BPa-blend of fruit pulp of Terminalia chebula (harad), fruit pulp of Terminalia bellerica (bahera), seed cake of Madhuca longifolia (mahua), seed cake of Azadirachta indica (neem) mixed in equal proportion and BPb-a blend of fruit of Phyllanthus emblica (amla), seed of Foeniculum vulgare (fennel) and seed of Trachyspermum ammi (ajwain) mixed in equal proportions were tested at 0, 10 and 20% of the substrate along with 0, 5 and 10% of calcium nitrate (CN) for their effects on in vitro methane production and feed fermentation. Inclusion of BPa (20%) + CN (10%) and BPb (20%) + CN (10%) did not affect gas production and feed digestibility but there was a significant (P<0.05) reduction (65 and 83.4 per cent) in methane production. Total volatile fatty acids were not affected by any of the treatments, whereas, acetate was increased and propionate and butyrate were significantly reduced resulting in increased acetate to propionate ratio by increasing the level of nitrate. Ammonia production was significantly increased by inclusion of CN irrespective of BPa doses but not affected when CN was used along with PBb. The results indicated that inclusion of CN was detrimental but when combined with either BPa or BPb, the values for in vitro feed digestibility were at par with control. However, BPb seems to be better than BPa, as inclusion BPb with CN maintained feed digestibility better than BPa and BPb also maintained ammonia nitrogen levels unchanged. The mixture of CN and BPb can be used as a feed additive for inhibition of methanogenesis in buffaloes without affecting feed fermentation.