PSVIII-23 Effects of different growth height on the yield, chemical composition, silage fermentation profile, in vitro and in situ digestibility of Broussonetia papyrifera

Abstract

Abstract Broussonetia papyrifera (BP) is a woody roughage source with high protein content. The experiment was conducted to explore the effects of different growth height (GH) on the BP yield, chemical composition, silage fermentation profile, as well as ruminants in vitro and in situ digestibility of different parts of BP. The three different harvested GH of BP were 0.8, 1.2, and 1.6 m, respectively. Samples from leaf, stem, and whole plant of BP were collected (each one has three replicates), making silage, and detected the nutritional composition of them. The results were analyzed by one-way analysis of variance with Duncan’s multiple comparisons. Fresh weight increased with the GH increased (P < 0.05). No significant difference was observed in dry matter (DM) and crude protein (CP) yield of leaf, and CP yield of whole plant between 1.2 to 1.6 m GH (P > 0.05). With the increase of GH, neutral detergent fiber (NDF) of BP increased, while CP content decreased (P < 0.05). Stem had the highest NDF and acid detergent fiber (ADF) content, and the lowest CP content and buffer capacity. The BP silage fermentation quality was deteriorated (lactic acid content decreased and pH values increased) with GH increased. For the different parts of BP, leaf silage had the highest pH and stem silage had the highest lactic acid content (P < 0.05). The leaf and its silage had the highest in vitro dry matter digestibility and gas production compared to others. The BP in situ digestibility were corresponded with in vitro results. DM, CP, NDF, and ADF effective digestibility rates of whole plant with 1.2 m GH were 439.6, 455.1, 412.9, and 381.3 g/kg, respectively. In conclusion, the BP nutritional quality decreased with GH increased and it could be used as a potential feedstuff for ruminants.