In vitro fermentation performance of alfalfa (Medicago sativa L.) mixed with different proportions of paper mulberry (Broussonetia papyrifera) leaves (PML) or condensed tannins extracted from PML

Abstract

Ruminants would suffer from gastric distension (bloat) when feeding on alfalfa (Medicago sativa L.; Alf), while tannins can relieve this problem. Thus, this study aimed to evaluate the effect of Alf mixed with paper mulberry (Broussonetia papyrifera) leaves (PML) or condensed tannins (CT) extracted from PML on in vitro fermentation performance. Seven experimental treatments based on the mass ratios of Alf and PML were set up: Alf, PML, 3A1P (Alf:PML = 3:1), 1A1P (Alf:PML = 1:1), 1A3P (Alf:PML = 1:3), A1P (Alf with 1% CT extracted from PML), A2P (Alf with 2% CT extracted from PML), and a blank. The results after fermentation were as follows. (1) The degradable dry matter (DDM) and degradable organic matter (DOM) contents increased simultaneously with the increase in the proportion of PML (p .05), propionic, and butyric acids compared to Alf alone. Adding CT improved the concentrations of propionic and butyric acids over the Alf treatment (p