Chemical composition and in vitro ruminal fermentation of pigeonpea and mulberry leaves

Mulberry and pigeonpea trees are two widely distributed trees in southwest regions of China, and grow well in summer and winter season respectively. The present study is to investigate the nutritive value of mulberry and pigeonpea leaves by using in vitro ruminal fermentation. Pigeonpea leaves were harvested in February, October, November and December, while mulberry leaves were harvested in May, July, September, October. Comparisons of chemical composition, kinetics of in vitro gas production, methane production, dry matter degradation and VFA production of pigeonpea and mulberry leaves were performed by using in vitro ruminal batch culture system. Pigeonpea and mulberry leaves had crude protein varying from 186 to 208 and 209 to 269 g/kg dry matter, respectively, and neutral detergent fiber ranging from 395 to 456 and 252 to 336 g/kg dry matter, respectively. In vitro fermentation indicated that pigeonpea leaves had lower in vitro dry matter degradation and theoretical maximum of gas production, but greater initial fractional rate of degradation and acetate to propionate ratio in comparison with mulberry leaves. Meanwhile, harvest time influenced the acetate to propionate ratio of both leaves. In conclusion, pigeonpea and mulberry leaves have protein content larger than 180 g/kg dry matter, and can be alternative protein resource for ruminants. In addition, harvest time significantly affect the fermentation pathway of these two leaves.