The Effects Of Malate On In Vitro Fermentation Of Rumen Micro-Organisms And The Metabolism Of Goat Rumen

The objective of this study is to investigate the effects of malate on the in in vitro batch fermentation of mixed ruminal microorganisms on different substrates. Furthermore, the effect of malate on the metabolism and fiber degradation of goat rumen were investigated in vivo. This thesis was described in the following four experiments.In the first experiment, the effect of malate on the fermentation of mixed ruminal microorganisms on different substrates of forage was investigated in vitro. In 17h incubations, the results showed that: In the case of wheat, 4 mmol.L^-1 and 8 mmol.L^-1 malate increased (P>0.05) linearly propionate concentration, and 12 mmol.L^-1 malate increased (P<0.05) significantly propionate concentration; In the case of leymus chinensis, all of malate treatments caused an increase (P<0.05) in propionate concentration compared with the control; In the case of hay, 12 mmol.L^-1 malate increased (P<0.05) propionate concentration, and all of malate treatments increased (P>0.05) total VFA concentration. Compared with the control, the value of the acetate : propionate ratio was decreased by the addition of malate for all substrates.In the second experiment, the effect of malate on the fermentation of mixed ruminal microorganisms on different substrates of concentrate was investigated in vitro. The results showed that the final pH increased (P<0.05) linearly for all substrates as the concentration of malate increased from 0 to 12 mmol.L^-1; When mixed ruminal microorganisms were incubated with wheat, corn and barely respectively, the total gas production increased, but the total gas production was not affected by the addition of malate when soluble starch was fermented; Malate increased (P>0.05) the OM degradability for all substrates; Malate decreased (P<0.05) lactate concentrate only when wheat of all substrates was fermented; Additon of malate increased (P<0.05) propionate and total VFA concentration and decreased (P<0.05) the value of the acetate : propionate ratio for all substrates.