鲫鱼、草鱼肠道吸收、转运酪氨酸和脯氨酸的研究

Study on the Absorption of L-Tyrosine and L-Proline by the Intestines of C.Auratus and Grass Carp in Vitro

采用同位素示踪法和肠道离体灌流模型研究了鲫鱼和草鱼肠道对酪氨酸(Tyr)、脯氨酸(Pro)的吸收量、吸收速率、跨壁运输量与氨基酸灌流时间和灌流浓度的关系。结果表明:随着Tyr、Pro灌流浓度的增加,鲫鱼、草鱼肠道的吸收速率与其浓度均呈正相关关系。但鲫鱼对Tyr、Pro的吸收转运速度明显高于草鱼。随着鲫鱼、草鱼肠道内Tyr、Pro灌流的浓度逐渐下降,留存于其肠道的两种氨基酸的比例也随之下降,而通过肠道转运到肠道外的比例则逐渐增加,但草鱼转运到肠道外的比例极显著低于鲫鱼(P<0.01)。一般,鲫鱼肠道对Tyr、Pro的总吸收率随着灌流氨基酸浓度的下降而下降,草鱼肠道对Tyr总的吸收率随着灌流氨基酸浓度的下降而呈上升趋势。对Pro的总吸收率以5mmol.L-1组(8.14%)最高。且鲫鱼对Tyr、Pro的总吸收率低于草鱼相应的氨基酸浓度组。

The study was conducted to determine the absorption of L-Tyrosine and L-Proline by the intestines of Crucian carp and grass carp in Vitro by using L-[4,5-3 H] Tyrosine,L-[2,3,4,5-3 H]Proline as tracers and adopting the in-vitro perfusion technique. The results indicate that along with the perfusion concentration of L-Tyr and L-Pro rising, all the transmural velocities of them across intestines of either Crucian crap or grass carp have a positive correlativity with amino acids perfusion concentration,but, Crucian crap is remarkably higher than grass carp in the transmural velocity of the two amino acids. As the perfusion concentration of L-Tyr and L-Pro gradually declined,the percentage of them retained in guts of the two fishes decreased respectively ,while the percentage of the transmural flux across the intestines increased gradually and that of grass carp is manifestly lower than that of Crucian crap（ P 〉 0.01 ）. To Crucian crap, the total absorptivity of L-Tyr and L-Pro in 40 minutes has a declining trend on the whole along with the perfusion concentration of amino acids decreasing; To grass carp, the total absorptivity of L-Tyr has a rising trend along with the perfusion concentration of amino acid decreasing. The total absorptivity of L-Pro is the heighest in the 5.0 mmol. L^-1 group（8. 14%）. Crucian crap is lower on the whole than grass carp in the total absorptivity of every concentration test team of L-Tyr and L-Pro.