Study For The Metabolic Rules Of Amino Acids In Portal-drained Viscera Of Pigs At Different Growth Stages

The objective of this paper is to determine the metabolic rules of amino acids in the portal-drained viscera(PDV) of pigs, and the experiments are as followed:The concentrations of amino acids(AA) of barrows at different stages of growth:eighteen healthy Duroc × Landrace × Yorkshire barrows weighing 20 ± 1.0 kg, 40 ± 1.0kg, 60 ± 1.0 kg were used in the experiment. The barrows were surgically fitted with permanent catheters in the mesenteric vein, portal vein, and carotid artery. After barrows were recovered from the surgeries, a priming dose(15 mL) of p-aminohippuric acid(PAH) solution was given via the mesenteric vein at 0730 h, followed by a constant infusion of PAH solution at a rate of 0.8 mL/min. Sixty min after administration of the priming dose, 5-mL blood samples were collected from each barrow from the hepatic vein, portal vein and carotid artery at 0830, 1000, 1200, 1430, and 1730. For 20, 40, and60 kg barrows, the ratios of the concentrations of Gly and Ala in the portal vein to that of TAA were 21.2%, 21.0%, and 20.9%, respectively, and the ratios of the concentrations of Gly and Ala in the carotid artery to that of TAA were 17.2%, 17.1%,and 17.2%, respectively. For 20, 40, and 60 kg barrows, the ratios of the concentrations of Gly and Ala in the portal vein to that of no essential AA(NEAA) were 47.5%, 48.2%,and 47.9%, respectively, and the ratios of the concentrations of Gly and Ala in the carotid artery to that of NEAA were 37.1%, 37.8%, and 38.2%, respectively.The fluxes of AA across the portal vein of barrows at different stages of growth. For20, 40, and 60 kg barrows, the ratios of the flux of essential AA(EAA) across the portal vein to that of TAA were 55.9%, 56.4%, and 55.9%, respectively; the ratios of the flux of Gly and Ala across the portal vein to that of NEAA were 49.0%, 48.3%, and 49.0%,respectively; the ratios of the flux of Gly and Ala across the portal vein to that of TAAwere 21.7%, 21.1%, and 21.7%, respectively; the ratios of Glu across the portal vein to that of NEAA were 19.2%, 19.9% and 20.5%, respectively; and the ratios of theflux of branched-chain AA across the portal vein to that of TAA were 17.9%, 18.3%and 18.3%, respectively.The net portal fluxes of AA. For 20, 40, and 60 kg barrows, the ratios of the net portal fluxes of EAA to that of NEAA were 174%, 172%, and 168%, respectively; the ratios of the net portal fluxes of NEAA to that of TAA were 36.1%, 36.7%, and 36.1%respectively; the net portal fluxes of Glu were-5.26 mg/min,-8.75 mg/min, and-13.0mg/min, respectively. For 20, 40, and 60 kg barrows, the ratios of net portal fluxes of Gly and Ala to that of NEAA were 105%, 104%, and 105%, respectively; the ratios of net portal fluxes of BCAA to that of TAA were 20.0%, 19.1%, and 18.7%, respectively,the ratios of net portal fluxes of Glu to that of NEAA were-20.1%,-18.7%, and-19.9%,respectively.In conclusion, 1) AA especially Glu were widely in PDV of barrows at different stages of growth(20 kg,40 kg,60 kg), resulting in producing a large amount of NH3-N;2) Gly and Ala were abnormally produced in the PDV instead of being dramatically consumed like other AA; 3) there was a negative correlation between the production of Gly and Ala in the PDV and the net portal flux of Glu(R2=0.7998, P < 0.001).