Effects Of Nicotinic Acid Supplement On Rumen Redox Status And Fermentation Index In Culture Medium Of Maize And Alfalfa In Vitro

Rumen redox status is the level of active oxygen. It reflects the nature of the rumen redox reactions and oxidative reductive strength. It also reflects the balances of rumen fluid oxidation and reduction. Changing the redox state has an important impact on the microbial metabolism. But the research of Redox Status in the rumen microorganisms are rare. The type of dietary and supplements can effect rumen redox state. Through vitro culture, the changes of redox status in different vitro culture system which adding niacin in maize or alfalfa cultivate substrate and its effect on fermentation index were investigated in this study, to explore the effect of niacin on the redox status and fermentation index,the mechanism of different feed types in regulating rumen redox status and ruminal fermentation. was also researched.Two-factor test experiment design was adopted in this study. It had 6experimental treatment and each treatment had 4 repeats. Factor A was the the type of substrate,were maize and alfalfa. Factor B was the additive amount of niacin and its antagonist, 800 mg and 4455 mg/kg DM, respectively. After cultured in vitro 24 h,measure various index. The results showed that:1?The discrepancy of fermentation index and redox status between maize and alfalfa was extremely significant. Compare with the maize control group, alfalfa control group can improve the concentration of niacin, the enzyme activity of NOX significantly, reduce NADPH and NADP(H) concentration, improve NADP+/NADPH significantly. It also can improve the ORP value of fermention liquid. Alfalfa can promote the multiplication of rumen microbes and fermentation of carbohydrate,improve TVFA, propionate concentration,butyrate concentration,and had no effect on acetate concentration and acetate /propionate. Because of decline of lactate concentration and rise of NH3-N concentration, the pH value of alfalfa control group was significantly high than maize control group.And it is no effect on enzyme activity of LDH between the two groups.2? At the main effect, niacin had no significant effect on redox status,it also had no effect on acetate,propionate and TVFA concentration,But it can improve NADH concentration,NAD(H) concentration,NADPH concentration,NADP(H)concentration, and reduce NAD+concentration, NADP+concentration and NAD+/NADH,NADP+/ NADPH slightly,and then lead the improve of enzyme activity of LDH and acetate concentration, propionate concentration and TVFA concentration.Compare with nicotinic acid, isoniazide had opposite effects on NAD+concentration ?NADP+concentration,enzyme activity of LDH, acetate concentration,propionate concentration,TVFA concentration. But on NADH concentration,NADPHconcentration, NAD(H) concentration,NADP(H) concentration and NAD+/ NADH,NADP+/ NADPH, isoniazide and nicotinic acid had same influences, even it had greater impact on NADPH concentration ? NADP(H) concentration andNADP+/NADPH than nicotinic acid. Compare with control group, isoniazide group can improve NADP+concentration,NADPH concentration andNADP(H) concentration significantly.3? Effects of niacin and substrate type on niacin concentration, ORP value,enzyme activity of NOX, NH3-N concentration,MCP concentration, butyrate concentration, acetate /propionate, lactate concentration and pH value had interaction.When the substrate was maize, the addition of niacin can reduce lactate concentration and improve pH value extremely significantly(P<0.01). When the substrate was Alfalfa, the addition of niacin can improve niacin concentration and reduce ORP value.4 ?The ORP value had significant negative correlation( P < 0.01) with pH value,acetate, propionate,TVFA,NH3-N and MCP concentration, had significant positive correlation(P<0.01)with lactate concentration.