PSVII-13 Evaluation of Ginkgo Leaf as a Feed for Ruminants by Using in Vitro gas Production Technique

Abstract The objective of this study was to examine the fermentation characteristics of ginkgo leaf compared with traditional feeds, rice straw, alfalfa and soybean meal, by using in vitro gas production technique. Three ruminal cannulated Chinese Holstein dairy cows were fed a total mixed ration. Rumen fluid was collected via from a ruminal cannula before feeding and then filtered through four layers of cheesecloth. Samples (220 mg air-dried) of rice straw, alfalfa, soybean meal and ginkgo leaf were placed in each glass bottle (150 mL), and 30 mL mixed solution with rumen fluid and a buffer solution (1:2 v/v). Three replicates of each sample were incubated in shaking bath at 39 °C for 48 h. The gas production was measured at 0, 3, 6, 9, 12, 24 and 48 h, respectively. The gas production data were fitted to the non-linear model Y = A + B (1 – e-CT). The results demonstrated that the ginkgo leaf had significantly greater in vitro gas production compared with the other feeds at each observation time. The amount of gas production from the immediately soluble fraction (A) of the four test feeds were all positive. The gas production from the insoluble fraction (B) of alfalfa was least at 43.82 mL and ginkgo leaf showed significantly greater B values than alfalfa. The gas production rate (C) was significantly greater for ginkgo leaf than those C values for rice straw and soybean meal. The in vitro dry matter and crude protein digestibility (%) of ginkgo leaf were 99.6 and 98.7, respectively, which were significantly greater than those of soybean meal. The total volatile fatty acid production of ginkgo leaf was significantly greater than that of rice straw, and the ammonia concentration of ginkgo leaf decreased significantly. It indicated that ginkgo leaf could be used as a protein source feed for ruminants.