酪蛋白小肽和氨基酸对草鱼(Ctenopharyngodon idella)血液循环和组织蛋白质合成的影响

EFFECTS OF SMALL PEPTIDE AND AMINO ACID ON PEPTIDE CIRCULATION AND TISSUE PROTEIN SYNTHESIS IN GRASS CARP CTENOPHARYNGODON IDELLA

采用草鱼前肠灌注和3H-Tyr同位素标记方法,进行酪蛋白小肽和氨基酸对草鱼血液循环和组织蛋白质合成的影响研究。结果表明,灌注酶解酪蛋白(CSP)溶液组的草鱼血液循环中总肽量为19430.82μv/μl,灌注游离氨基酸(FAA)溶液组的草鱼血液循环中总肽量为16033.00μv/μl,前者显著高于后者(P<0.05),同时前者的大多数肽段肽量也高于后者,2组血浆中某些肽段肽量有显著(P<0.05)或极显著差异(P<0.01)。CSP与FAA组草鱼肠道、肝脏、背肌组织蛋白质合成率(%/d)分别为96.84和72.25,98.64和81.65,65.38和46.59,CSP组草鱼显著或极显著高于FAA组(P<0.05或P<0.05)。草鱼血浆中总肽量和某些肽段肽量分别与草鱼肠道、肝胰脏和背肌组织蛋白质合成率有明显的正相关。实验表明,肠道对酪蛋白小肽的迅速吸收和进入血液循环中的某些小肽可能是促进草鱼组织蛋白合成的重要因素。

An experiment to study the role of small peptides in amino acid absorption and in protein synthesis of grass carp Ctenopharyngodon idella that administered with a large dose of glycyltyrosine and a tracer doses of ^3H-Tyr and casein enzymatic hydrolysate-CSP or the same composition of FAA. Five fish individuals were sampled for trail vein blood and then sacrificed in nonanaesthesia 20min later. The fractional rates of tissue protein synthesis （FRS） were estimated by measuring the specific radioactivities of free and protein bound 3H-Tyr post administration. The peptides of plasma were analyzed by HPLC after deproteinization and filtration with 10kDa weight cut-off filters. The total amount of peptides in the blood of both groups was 19430 and 16033uv/ul, respectively, showing much higher value for fish given CSP than that given FAA （P〈0.05）. Significant difference was found between the two groups in some peptides amounts. The protein bound specific radioactivity of tissue in CSP-given fish was more significant （P〈0.05 or 0.01） than that of the FAA-given. The FRSs of intestine, hepatopancreas, and backside muscle in CSP and FAA groups were 96.84%/d and 72.25%/d, 98.64%/d and 81.65%/d, 65.38%/d and 46.59%/d, respectively. There was a significant correlation between the amount of total peptides and some peptides with the FRS of liver and intestinal protein. The results suggest that peptides could pro- mote the tissues protein synthesis in the grass carp.