| The present research was conducted to investigate the influence of fumarate and itssodium on rumen fermentation and ruminal bacterial communities of goat. By comparingthe effects of fumarate and its sodium (fumarate,sodium fumarate and disodium fumarate)on rumen fermentation, the proper adding levels of fumarate in vitro was established. Byusing different incubation condition (including concentrate, forages and differentconcentrate: forage ratio diets), we evaluated the effects of disodium fumarate on rumenfermentation and methane production in vitro. Furthermore, the effect of disodium fumarateaddition on rumen fermentation, plasma metabolites and ruminal bacterial community invivo was investigated. This dissertation was described in the following seven sections.1 Effect of fumarate addition on rumen fermentation in vitroRumen contents from three local male goats with permanent rumen fistulae wereincubated in anaerobic media with substrate consisting of rice straw powder (0.4 g) andcorn (0.6g). The effects of fumarate with final concentrations at 4,8 and 12 mmol·L-1 onthe ruminal fermentation were investigated. Results showed that, as compared with thecontrol, total volatile fatty acids(TVFA), propionate production(P%) and total gasproduction for the group treated with fumarate increased (P＜0.05), while the ration ofacetate to propionate and pH decreased (P＜0.05). The effect of fumarate was moresignificant as its concentration increased, suggesting its dose dependent effect. The resultsindicated that fumarate addition stimulated the fermentation activity of rumen microbesfrom goat, while lowered the pH of the medium (P＜0.01).2 Comparisons of effects resulting from fumarate and its saltsaddition on fermentation by rumen micro-organisms in vitroRumen contents from three local male goats with permanent rumen fistulae wereincubated in anaerobic media with substrate consisting of cracked corn, soybean meal andryegrass particle. The effects of fumarate, sodium fumarate or disodium fumarate with final concentrations at 4, 7 and 10 mmol·L-1 on the in vitro fermentation were compared. Resultsshowed that, as compared with the control, total volatile fatty acids (TVFA), propionateproduction (P%) and total gas production for all treatments increased significantly, while theratio of acetate to propionate and lactic acid production decreased significantly(P＜0.05). At0 h or 24 h of incubation, the pH value in the group treated with disodium fumarate washigher than that of fumarate or disodium fumarate treatment. No significant difference wasobserved in other ruminal characteristics among the three treatments. The results showedthat fumarate and its salts addition could stimulate the rumen fermentation, while thedisodium fumarate had a better beneficial effect on the in vitro fermentation by rumenmicroorganisms.3 Influence of disodium fumarate addition on the fermentation ofconcentrates by rumen microorganisms in vitroFour experiments were conducted to investigate the effects of disodium fumarate onthe in vitro fermentation profiles of concentrate feed. In experiment 1, mixed concentratediets (0.7 g cracked corn, 0.3 g soybean meal and 0.43 g festuca elata, DM basis) werefermented in vitro by rumen microorganisms from local goats. Results showed that ascompared with the control, total volatile fatty acids(TVFA), the percentage of propionate(P%) , total gas production and the dry matter loss for the disodium fumarate treatmentincreased (P＜0.05),while the ratio of acetate to propionate and lactate production decreasedsignificantly. In experiment 2, a time course study was conducted to investigate the effect ofdisodium fumarate at 7 mmol·L-1 on rumen fermentation in vitro. The results showed thatdisodium fumarate addition increased the cumulative gas production, pH, propionate andTVFA production, and reduced the ratio of acetate to propionate, whereas no treatmenteffect was observed for the NH3-N concentration and the amylase activity. Disodiumfumarate addition tended to lower the lactate production(P＜0.05).With the exception ofTVFA production, there was significant interr-reaction effect between the disodiumfumarate treatment and fermentation time(P＜0.05). In experiment 3, influences of disodiumfumaratc addition on fermentation of cracked corn and cracked wheat by rumenmicroorganisms in vitro were investigated. The results showed that during 24 h ofincubations, disodium fumarate addition increased (P＜0.05) the gas production and the pHfor the two substrates, but this effect was not observed for other fermentation characteristics.In experiment 4, the effect of disodium fumarate addition on rumen lactic acidosis in vitro was investigated. Lactic acidosis was induced by in vitro fermentation at 39℃for 24 hwith a 25 g·L-1 test diet. The result showed disodium fumarate addition decreased lactateconcentration (P＜0.01). These results suggest that the addition of disodium fumarate toruminant feed could stimulate the in vitro fermentation of rumen microbes from goat,whereas this effect on changes of ruminal character tics may largely depend on the generalnature of the substrates.4 Influence of disodium fumarate addition on the fermentation offorages by mixed rumen microorganism, Ruminococcus flavefaciensand rumen fungusThree experiments were conducted to investigate the effect of disodium fumarate onfermentation of forage by mixed rumen microorganism, Ruminococcus flavefaciens andrumen fungus. In experiment 1, rumen contents from three local male goats with permanentrumen fistulae were incubated in anaerobic media with substrate including rice straw,festuca elara and ryegrass, and effects of disodium fumarate with final concentrations at7mmol·L-1 on the in vitro fermentation was investigated. The results showed that disodiumfumarate addition increased the total gas production for all the substrates. As comparedwith the control, the addition of disodium fumarate increased the dry matter loss by 26.22% (P＜0.05), 14.16% (P＜0.05) and 28.54%(P＜0.01), receptively. In experiment 2, theeffect of disodium fumarate on the fermentation activity of Ruminococcus flavefaciens wasinvestigated. Disodium fumarate was added to the incubation bottles to achieve finalconcentrations of 0, 4, 7 and 10 mmol·L-1. Results showed that disodium fumarate additionincreased the dry matter loss, TVFA production and the counts of Ruminococcusflavefaciens(P＜0.05). In experiment 3, the effect of disodium fumarate on the ryegrass offermentation by the rumen fungus was investigated. The results showed that the disodiumfumarate addition (0, 4, 7 and 10mmol·L-1) reduced the dry matter loss and the cumulativegas production (P＜0.01).In conclusions, the diosodium fumarate addition could stimulate.the fermentation activity of the mixed rumen micro-organism and Ruminococcusflavefaciens, whereas reduced the fermentation activity of the rumen fungus.5 Effects of disodium fumarate on in vitro methane production andfermentation of diets differing in their forage:concentrate ratioEffects of disodium fumarate on CH4 production and fermentation of three diets differing in their concentrate content by rumen micro-organisms were investigated by batchcultures. Rumen contents were collected from three local goats. Disodium fumarate wasadded to the incubation bottles to achieve final concentrations of 0, 4 and8mmol.L-1 -fumarate.Results showed that disodium fumarate addition increased linearly(P＜0.001) the final pH, acetate and propionate production, and reduced the amount ofNH3-N in the cultures. As compared with the control, adding disodium fumarate to batchcultures reduced CH4 production. Disodium fumarate tended to increase (P＜0.05) theMCP(rumen microbial protein) for the high-forage diet, but no differences (P＜0.05) wereobserved for the high-concentrate diets. These results indicate that the effects of disodiumfumarate on rumen fermentation mainly depend on the nature of the incubated substrate,with the high-forage diet showing the greatest response.6 Influence of disodium fumarate addition on rumen fermentationand ruminal bacterial community in vitroTwo experiments were conducted to investigate the effect of disodium fumarateaddition on the ruminal fermentation of different kinds of diet (festuca elata, mixed diet andconcentrate diet) in vitro. In experiment 1, effects of disodium fumarate with finalconcentrations at 7mmol.L-1, on the in vitro fermentation and the changes of rumen bacteriawas investigated. Results showed that disodium fumarate addition increased (P＜0.05) thecumulative gas production, pH and the TVFA production, and reduced the lactic acidproduction (P＜0.05). The analysis of DGGE profiles revealed that disodium fumarateaddition affected the composition of the rumen bacteria communality. In experiment 2, gasproduction was monitored and the cumulative values were fitted to a mono-phasic curve.For all substrates, disodium fumarate treatment increased the asymptotic gas production (A)and the max rate of gas production (P＜0.05), whereas no treated effects (P＞0.10) wereobserved for the half-time C with the exception of mixed diets (5:3:2, DM basis).Collectively, these results suggest that disodium fumarate is effective in increasing the pHand gas production for the diets differing in forage: concentrate ratio in vitro, whereas itseffect on changes of ruminal microbial community may largely depend on the generalnature of the substrate.7 Effect of disodium fumarate on ruminal and plasm metabolites andthe ruminal bacterial communities in goats Effects of disodium fumarate on ruminal metabolism and changes of rumen microbialcommunity were investigated. Results showed that disodium fumarate treatment increasedthe pH (P＜0.05) and reduced the lactate production (P＜0.05), whereas did not affect theproduction of acetate, propionate, butyrate and TVFA production significantly (P＜0.05).Disodium fumarate addition did not influence the plasma of concentrations of glucose, ureaN, cholesterol and triacylglycerol, but reduced the concentration of lactate. The analysis ofDGGE profile revealed that, as compared with the control, disodium fumarate treatmentshowed a higher degree of bacterial diversity (P＜0.05). A clone library was created fromcomplete 16S rDNA. From the library, 12 clones had their V6-V8 regions matchedpredominant bands on the DGGE gel and their 16S rDNA were then sequenced andsubjected to an online similarity search. Four of the clones showed their similarities over97% with database sequences, with two sequences similar to Succinivibrio dextrinosolvensand Streptococcus bovis, with other two were similar to those unidentified rumen bacteria,Others clones had their similarities in the range of 88%～96% with database sequences. Ascompared with the control, Succinivibrio dextrinosolvens, Butyrate-producing bacteriumSL7/1, Uncultured rumen bacteria, Clostridium hathewayi and Prevotella salivae becamethe predominant bands after disodium fumarate addition. Results indicated that disodiumfumarate addition was effective in improving the pH value and lowering the lactate in therumen, and stimulating the growth of some ruminal bacteria.
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