Effects Of Different Lactic Acid Bacteria On Rumen In Vitro Fermentation Characteristics In Dairy Cattle

The objective of this trial was to preliminarily explore and compare the effects ofLactobacillus plantarum; Lactobacillus acidophilus; Enterococcus faecalis on thecharacteristics of in vitro fermentation, to predict their potential influences on theproduction performance of dairy cows, and to provide the practical application ofactive yeast to ruminants production and the regulation of nutrition physiology withtheoretical and technological basis. The study was conducted as one-factor blockexperimental design, and four supplemental levels of Lactobacillus plantarum (0.00、0.25×107cfu/mL、0.50×107cfu/mL and0.75x107cfu/mL) were tested to analyze theinfluence of different levels of Lactobacillus on in vitro fermentation parameters. The results showed that there was a significant increase of FRDo (p<0.0001) andgas production (p<0.05) with the supplemental levels improvement when the substratewas maize stover; and there was a significant improvement in gas production (p<0.01)at the end of fermentation for rice straw. In vitro NH3-N concentration of twosubstrates enhanced significantly with the improvement of supplemental levels ofLactobacillus plantarum (p<0.01). However, there was no significant difference(P>0.05) on the NDFD, DMD, VFA contents and pH value with the change ofsupplemental levels of Lactobacillus plantarum. Results suggested that addingLactobacillus plantarum could promote the nitrogen metabolism of the two substratesand maintain the pH balance in in vitro fermentation. The results of the second part showed that the initial gas velocity (FRDo) wereincreased for maize stover and rice straw respectively when supplementedLactobacillus acidophilus and presented a liner increasing effect withsupplementation levels (P<0.01). The NH3-N concentration of maize stover and ricestraw were enhanced respectively after adding Lactobacillus acidophilus andsupplementation levels presented a linear increasing effect for both of the substrates(P<0.01). No influences on the other indicators were observed after addingLactobacillus acidophilus., including half-life (to.5), neutral-detergent fiberdisappearance, dry matter disappearance, CH4production, total VFA, A:P. Theoutcome of this research indicated that adding Lactobacillus acidophilus could improve in vitro gas production of maize stover and rice straw, and promote nitrogen metabolism of the two substrates in in vitro fermentation.The outcomes of the third part showed that there was a significant improvement in gas production in the final period and FRDo for maize stover after adding Enterococcus faecalis, and enhanced the gas production of rice straw in the middle and later periods of in vitro fermentation. There were no influences on in vitro fermentation parameters(i.e. in vitro DMD, NDFD, CH4production, NH3-N concentration, pH value total VFA production and A:P ratio). Further study is needed to investigate the effects of direct supplementation of Enterococcus faecalis on in situ degradation or in vivo digestibility and performance in ruminants.