Effects Of Different Dietary Concentrate To Forage Ratios On Fatty Acid Metabolism Of Rumen,Pdv Tissue And Liver In Dairy Goats

The study was conducted to determinate difference dietary on VFA concentration of rumen fluid, peripheral blood and the total flow, composition of VFA, LCFA of portal vein, Hepatic vein in dairy goats by applied the technique of permanent rumen fistula, chronic vascular fistula of splanchnic and determination of blood flow. To study the effect of dietary concentrate to forage ratios on VFA metabolism of rumen fluid, PDV tissue, liver and LCFA metabolism of liver. The results will provide the scientific basis for formulate diet of dairy goats. This study included three experiments:In trial1, the aim of this experiment was to evaluate the effects of differenct dietary concentrate to forage ratios on pH value of rumen fluid and VFA concentration of rumen fluid and blood in dairy goats.8dairy goats with permanent rumen fistula were randomly divided into two groups in a randomly block design. Animals were fed two kinds of diets with different concentrate to forage ratios, which were6:4(concentrate:roughage=6:4, HC) and4:6(concentrate:roughage=4:6, HR). The experimental period included15days adaptation and3days samples collection. The results showed that, HC diet decreased pH value of rumen fluid compared with HR diet (P＜0.05), the pH value decreased to minimum at3h post-feeding and the pH value were5.71and6.08, respectively. Except acetic acid, the concentrations of propionate, isobutyrate, butyrate, isovalerate, valerate and TVFA of rumen fluid in HC were higher than in HR and increased4.99%、5.58%、21.81%、17.95%、18.27%、1.66%, respectively. All of VFAs plasma concentrations in HC group were higher than than in HR group, especially, the concentrations of propionate and butyrate reached significant level (P<0.05). The ratio of acetate to propionate of rumen fluid and plasma in goats fed HC diets were both lower compared with HR diets, but the difference was not significant (P>0.05). The maximum concentrations of acetate, propionate and TVFA in HC diet and HR diet were showed at2h and3h post-feeding respectively. The maximum concentration of VFA in plasma were observed at2h post-feeding, and then reduced to before feeding levels gradually in both two diets.In trial2, the aim of this experiment was to research the effects of differenct dietary concentrate to forage ratios on VFA metabolism of PDV tissue and liver in dairy goats.6dairy goats with mesenteric, portal, hepatic vein and femoral artery vascular fistula were randomly divided into two groups in randomized crossover trial designed. Animals were fed two kinds of diets with different concentrate to forage ratios, which were6:4(HC) and4:6(HR). The experimental included2periods,15days adaptation and3days samples collection in each periods. The results showed that, Mean plasma concentration of acetate, propionate, butyrate, isobutyrate, isovalerate and TVFA were higher (P<0.05) and ratio of acetate to propionate was lower (P<0.05) in portal, hepatic vein and artery in goats fed HC compared to the HR diets, except butyrate (P=0.118) in artery and acetate tended to increase in portal (P=0.050) and hepatic (P=0.084) vein. Plasma flow of acetate in portal and hepatic vein and butyrate in portal vein were not affected by diets, and other VFAs flows were higher (P＜0.05) in portal, hepatic vein and femoral artery in goats fed HC compared to the HR diets. Net acetate was produced and net propionate, butyrate, isobutyrate and isovalerate were absorbed by liver in goats fed either diet. The concentration increased after feeding at2h (P<0.05) for portal, hepatic and arterial plasma acetate, and at2h (P＜0.05) for portal and hepatic plasma propionate and butyrate and then decreased from that time in goats fed either diet. Net portal appearance increased (P＜0.05) at4h post-feeding for acetate in HC and at2h in HR diets, for propionate at2h in both the diets, and for butyrate at4h in HC and at2h in HR diets, respectively. Net gut plus hepatic output increased (P＜0.05) after feeding for acetate at4h in HC and at2h in HR diets, for propionate at2h in HR diets, and for butyrate at2h in HR diets. The post-feeding maximum net hepatic absorption were for propionate, and for butyrate at6h,4h in HC and2h in HR diets, respectively. While the post-feeding maximum net hepatic acetate output was (P>0.05) at2hr in HC and at6hr in HR diets.In trial3, study the effect of differenct dietary concentrate to forage ratios on LCFA metabolism of liver in dairy goats. Trial design, grouping and feeding were same with test2. The results showed that, Mean portal, hepatic vein and femoral artery plasma concentration and flow of C16:0, C18:0, C18:1n9t, C18:1n9c, C24:1n9, C18;2n6t, C18:2n6c, C18:3n6were higher in goats fed HC compared to the HR diets, especially, Mean portal, hepatic vein and femoral artery plasma concentration and flow of C18:1n9t and C24:1n9reached significant level (P<0.05). Mean portal, hepatic vein and femoral artery plasma concentration and flow of C20:4n6and C20:5n3were lower in goats fed HC compared to the HR diets, especially, Mean portal vein concentration of C20:4n6reached significant level (P<0.05), Mean portal vein concentration of C20:5n3, hepatic vein, femoral artery concentration of C20:4n6and portal vein flow of C20:4n6, C20:5n3tended to decrease (P<0.1). Total portal, hepatic vein and femoral artery plasma concentration and flow of SFA, MUFA, PUFA were higher in goats fed HC compared to the HR diets, however, there were no significant differences between the groups (P>0.05). Sampling time were no significant to concentration and flow of LCFA in liver, except portal vein concentration of C18:1n9t and portal, hepatic vein flow of C18:2n6c· Portal, hepatic vein and femoral artery plasma concentration and flow of UFA increase and SFA decrease in goats fed HC compared to the HR diets.In conclusion, the pH value of rumen fluid were decreased significantly and the VFA concentration of rumen and plasma were increased in goats fed HC diets, except acetate concentration of rumen fluid. Portal, hepatic vein and femoral artery plasma concentration and flow of all kinds of VFA and TVFA were higher and ratio of acetate to propionate was lower in goats fed HC compared to the HR diets(P<0.05). Net acetate was produced and net propionate, butyrate, isobutyrate and isovalerate were absorbed by liver in goats fed either diet. Portal, hepatic vein and femoral artery plasma concentration and flow of LCFA was higher in goats fed HC compared to the HR diets.