Effects Of Diets Of Different Concentrate To Forage Ratio On Amino Acids And Glucose Metabolism Of Liver In Dairy Goats

The study was conducted to investigate the effects of diets of different concentrate to forage ratio on amino acid and glucose metabolism of liver in dairy goats. The technology of chronic vascular fistula and blood flow measurement were used and mid-lactating dairy goats were chosen as the experimental animals to study the dynamic changes and the metabolic regularity of amino acids and glucose in liver.Trial 1, Six healthy mid-lactating Xinong Saanen dairy goats with catheters placed in the portal vein, a branch of the hepatic and femoral artery were used in a randomized crossover trial design to evaluate the effects of concentrate to forage ratio on amino acid and nitrogen metabolism in liver. Diets consisted concentrate and forage, the concentrate to forage ratio were 4:6 (High forage diet, HF) and 6:4 (High concentrate diet, HC). The results showed 1):the portal plasma concentrations of isoleucine, leucine, lysine, methionine, histidine, aspartate, arginine, branched chain amino acids and total essential amino acids were higher, especially isoleucine, methionine (P<0.05), while the concentrations of glucogenic amino acids and total amino acids were lower, but no markedly difference (P>0.05) when goats fed HC diet than HF diet; In hepatic vein, the lysine concentration was markedly higher (P<0.05) and the concentrations of alanine, glycine, proline were markedly lower (P<0.05) when goats fed HC diet than HF diet, and other amino acids were no significantly difference (P>0.05); Except the concentrations of lysine, other amino acids concentration were no obviously change (P>0.05) in femoral artery when goats fed HC diet compared with HF diet, and the concentrations of branched chain amino acids, total essential amino acids, glucogenic amino acids and total amino acids were no obviously change (P>0.05). There were no markedly effects (P>0.05) on plasma NH3 concentration in portal vein, hepatic vein, femoral artery in two diets; The plasma urea concentration in portal vein, hepatic vein, femoral artery were markedly higher (P<0.05) in goats fed HC diet than HF diet.2):Compared with HF diet, net portal appearance of branched chain amino acids, total essential amino acids, and total amino acids in HC was markedly higher (P<0.05); Net hepatic release of branched chain amino acids, total essential amino acids, glucogenic amino acids and total amino acids were higher, while their net splanchnic output were lower, but no evidently difference (P>0.05) when goats fed HC diet than HF diet; There were no evidently (P>0.05) effects on plasma NH3 and urea net flux in the portal-drained viscera, liver and total splanchnic tissue.Trial 2, This experiment was conducted to evaluate the effects of the diets of different concentrate to forage ratio on non-protein amino acids metabolism in liver of dairy goats. The experimental design was same with trial 1. The results showed that concentrations of P-Ser, α-AAA, Cit, α-ABA, EOHNH2, Hylys,1-Mehis,3-Mehis, Tau and Orn were higher, especially Tau and Orn (P<0.05), while the concentrations of β-Ala, β-AiBA, Ans and Hypro were lower in the portal plasma, but no markedly difference (P>0.05) when goats fed HC diet compared with HF diet; The Hypro concentration was markedly lower (P<0.05) and other non-protein amino acids in hepatic vein and femoral artery were no significantly difference (P>0.05)when goats fed HC diet than HF diet. All of non-protein amino acids concentrations were lower in femoral artery than in portal plasma and hepatic vein. Except net portal appearance flow of a-ABA was markedly higher and net hepatic release of a-AAA, Cit and 3-Mehis were markedly lower in HC diet than HF diet, there were no markedly (P>0.05) effects on plasma non-protein amino acids net flux in the portal-drained viscera, liver and total splanchnic tissue.Trial 3, This experiment was conducted to evaluate the effects of the diets of different concentrate to forage ratio on glucose metabolism of portal-drained viscera and liver in dairy goats. The experimental The experimental design was same with trial 1.The results showed that the dynamic trend of glucose concentration in portal, hepatic vein and femoral artery were consistent in two diets; Compared to HF diet, glucose concentration was higher, and net portal appearance of glucose, net hepatic release and net splanchnic output of glucose were lower but no markedly difference (P>0.05) in HC diet; The concentrations of insulin, glucagon, growth hormone and IGF-1 in hepatic vein were higher but no obviously difference (P>0.05) when goats fed HC diet than HF diet.