Effect of different bacterial agents on the quality of pigeon pea stems and leaves silage and the impact of microbial flora diversity

Abstract

Pigeon pea (Cajanus cajan L. Millsp.) is a perennial legume forage grass which is cultivated widely in in semiarid and tropical subregions of Asia and Africa[1]. Since it contains a rich source of crude protein and certain active substances (i.e., polysaccharides, flavonoids and stilbenes), which can greatly improve the rate of livestock weight gain and feed conversion [2-5]. Adding chemical or biological additives to pigeon pea silage has become an efficient strategy to improve silage quality [6-7]. Nevertheless, little is known about how addition of such additives affects the chemical and bacteriological changes occurring in the grass silage. Therefore, to investigate the positive influence of adding mixed bacterial agents on the nutritive composition of fermentation quality of pigeon pea silage, we initially evaluated the content of dry matter (DW), water soluble carbohydrates (WSC), crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF), organic acids (i.e., acetic acid and lactic acid), ammonia nitrogen (AN) and in pigeon pea silage individually treated with either microbial fermenting agents (MFA), high efficiency compound bacterial enzyme preparation (HECBEP) or bio-feed fermenting agents (BFFA). To further determine the relationship between bacterial flora and fermentation parameters of pigeon pea silage, we subsequently determined the bacterial flora abundance and their structural composition using high-throughput sequencing and spearman correlation analysis. We found that that addition of MFA to pigeon pea silage highly contributed to the increase of the contents of CP while the decrease of NDF and ADF(Table.1), as well as the increased abundance of Lactobacillus which had positive correlation with the ratio of Lactic acid/acetic acid (LA/AA) and pH value(Fig.1). Our results highlighted that adding MFA would be beneficial for nutritive values and fermentation quality of pigeon pea silage. Collectively, our study first evident that MFA can be used as a potential silage additive to