不同硒源及硒水平对大鼠生长性能、血清抗氧化能力和组织硒沉积的影响

Different Selenium Sources and Levels Affect Growth Performance,Serum Antioxidant Ability and Tissue Selenium Retention in Wistar Rats

本试验旨在考察不同硒源及硒水平对大鼠生长性能、血清抗氧化能力及组织硒沉积的影响,并以亚硒酸钠和商品酵母硒(酵母硒B)为参比,对本课题组用糖蜜和尿素为发酵底物研制的酵母硒(酵母硒A)生物学效价进行评定。将硒耗竭2周后的70只8周龄左右Wistar雌性大鼠称重,随机分到10个处理,每个处理7个重复,每个重复1只大鼠,分别饲喂不同处理的饲粮21d。处理1不添加任何形式的硒源,处理2～9在基础饲粮中分别以亚硒酸钠或酵母硒A的形式添加0.1、0.2、0.3和0.4mg/kg硒,处理10以酵母硒B形式添加0.3mg/kg硒。结果表明:1)不同硒源及硒水平对大鼠生长性能、血清谷胱甘肽过氧化物酶(GSH-Px)和超氧化物歧化酶活性影响不显著(P>0.05);2)组织硒含量随饲粮硒水平的升高极显著增加(P<0.01),添加酵母硒A组大鼠组织硒含量显著高于亚硒酸钠组(P<0.05);3)以亚硒酸钠为参比,血清GSH-Px活性及肝脏、肾脏和肌肉硒含量作为判定指标,酵母硒A的相对生物学效价分别为95.9%、127.5%、114.5%和101.2%;4)添加酵母硒A和酵母硒B对大鼠生长性能、血清抗氧化能力的影响不显著(P>0.05),但添加酵母硒A组大鼠肾脏硒含量极显著高于酵母硒B组(P<0.01),而酵母硒B在肌肉中有更多的硒沉积(P<0.01)。结果提示:1)硒源对大鼠组织硒沉积有较大影响,酵母硒相对于亚硒酸钠具有更高的生物学效价,但不同酵母硒之间存在一定的差异;2)饲粮硒水平对大鼠血清抗氧化能力影响较小,以血清GSH-Px活性为衡量标准,0.1mg/kg硒的酵母硒和亚硒酸钠都能满足大鼠的需要,但更高水平的酵母硒可以使大鼠组织中有更多硒的储备。

This experiment was conducted to investigate the effects of different selenium(Se) sources and levels on growth performance,serum antioxidant ability and tissue Se retention in Wistar rats,and to assess the bioavailability value of Se-yeast A produced using molasses and urea as carbon source and nitrogen source in our laboratory,compared with sodium selenite and commercial Se-yeast(Se-yeast B).A total of 70 Wistar rats aged about 8 weeks after two-week Se-depletion experiment were weighted and allotted to 10 treatments with 7 replicates per treatment and 1 rat per replicate.The rats were fed one of the 10 diets(a basal diet,the basal diet with 0.3 mg/kg Se from Se-yeast B,the basal diet with 0.1,0.2,0.3 and 0.40 mg/kg Se from Se-yeast A or sodium selenite) for 21 days.The results showed as follows: 1) Se sources and levels did not influence growth performance,serum glutathione peroxidase(GSH-Px) and superoxide dismutase(SOD) activities(P>0.05);2) tissue Se content was increased linearly as the dietary Se level increased(P<0.01),but the increase was markedly higher when Se-yeast A was fed(P<0.05);3) according to slope ratio assay,the bioavailability values of Se-yeast A were 95.9%,127.5%,114.5% and 101.2% compared with sodium selenite,when serum GSH-Px activity and Se content in liver,kidney and muscle were used as indicators,respectively;4) there were no significant differences on growth performance,serum antioxidant ability in rats between Se-yeast A and Se-yeast B(P>0.05),but rats fed Se-yeast A had more Se retention in kidney and less Se retention in muscle than those fed Se-yeast B(P<0.01).These results indicate that different Se sources have great effects on the deposition of tissue Se,and Se-yeast has higher bioavailability value than sodium selenite,but there are some differences between Se-yeast A and Se-yeast B;different Se levels have less influence on antioxidant ability,if serum GSH-Px activity is used as standard,then 0.1 mg/kg Se-yeast or sodium selenite can meet the needs of the rats,but higher level of Se-yeast has more tissue Se reserve.