| 摘要: |
| 【目的】研究饲料中不同蛋氨酸水平对洛氏鱥（Rhynchocypris lagowskii Dybowski）生长、消化酶和蛋白质代谢酶活力的影响。【方法】以初始体质量为 (13.63±0.01) g/尾的洛氏鱥幼鱼为研究对象，以鱼粉、豆粕和玉米蛋白粉为蛋白源，玉米油和鱼油为脂肪源，面粉和糊精为糖源，配制成6种等氮、等能的配合饲料，其中添加蛋氨酸使饲料中蛋氨酸水平为0.74%（对照组），1.03%，1.33%，1.62%，1.92%和2.21%，进行为期8周的饲养试验。饲养试验结束后，测定洛氏鱥肌肉的主要营养成分及蛋白酶、淀粉酶、脂肪酶、谷草转氨酶以及谷丙转氨酶活力。【结果】随着蛋氨酸水平的增加，洛氏鱥体质量增加率、特定生长率、饲料效率及蛋白质效率呈先升高后降低趋势;饲料中蛋氨酸水平为1.62%时，洛氏鱥的体质量增加率、特定生长率、饲料效率及蛋白质效率显著高于对照组（P<0.05）；而各组肥满度、脏体比与肝体比差异不显著（P＞0.05）。根据特定生长率与饲料中蛋氨酸水平的折线模型拟合，当特定生长率达到最大时，洛氏鱥饲料中蛋氨酸需求量为1.43%。饲料中蛋氨酸水平为1.33%和1.62%时，洛氏鱥肌肉中粗蛋白质含量显著高于对照组（P<0.05）；各组粗脂肪和粗灰分含量差异不显著（P＞0.05）。洛氏鱥肝胰脏、前肠、中肠、后肠的蛋白酶、淀粉酶、脂肪酶活力均呈先升高后降低的趋势，当饲料中蛋氨酸水平为2.21%时，后肠蛋白酶活力显著低于对照组（P<0.05），肝胰脏、前肠、中肠蛋白酶活力与对照组差异不显著（P＞0.05）；饲料中蛋氨酸水平对洛氏鱥肝胰脏、前肠、中肠和后肠淀粉酶与脂肪酶活力均无显著影响（P＞0.05）；洛氏鱥肝胰脏中谷草转氨酶、谷丙转氨酶活力呈先升高后降低趋势，当蛋氨酸水平为1.62%时，谷草转氨酶活力显著高于对照组（P<0.05）；当蛋氨酸水平为1.62%和1.92%时，谷丙转氨酶活力显著高于对照组（P<0.05）。【结论】从生长性能及消化代谢角度来看，洛氏鱥配合饲料中蛋氨酸适宜水平为1.33%～1.62%。 |
| 关键词: 洛氏鱥 蛋氨酸 消化酶 蛋白质代谢酶 生长性能 |
| DOI： |
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| 基金项目:吉林省科技厅重点科技攻关项目（20160204019NY） |
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| Effects of methionine level on growth performance and activities of digestive enzymes and protein metabolism enzymes of Rhynchocypris lagowskii Dybowski |
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DUAN Jing,WU Lifang,WANG Jingyao,et al
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| Abstract: |
| 【Objective】Effect of different methionine levels in feed on growth performance and activities of digestive enzymes and protein metabolic enzymes of Rhynchocypris lagowskii Dybowski were investigated.【Method】Six methionine levels of 0.74%(CK),1.03%,1.33%,1.62%,1.92% were 2.21% were configured in six isonitrogenous and isocaloric diets,using fish meal,soybean meal and corn gluten as protein sources,corn oil and fish oil as fat sources,and flour and dextrin as carbohydrate sources.Each diet was fed to Rhynchocypris lagowskii Dybowski with initial body weight of (13.63±0.01) g.After 8 weeks,the main nutrient components of muscles and activities of amylase,lipase,glumtaic pyruvic transaminase and glutamic oxalacetic transaminase and protease were determined.【Result】With the increase of methionine level,weight gain rate, specific growth rate,feed efficiency,and protein efficiency of Rhynchocypris lagowskii Dybowski increased first before decreasing,getting to significantly higher than that of the control group (P<0.05) when the level of methionine was 1.62%.There was no significant difference in condition factor,hepatosomatic index and viscera somatic index (P>0.05).According to the polyline model of the specific growth rate and methionine level in feed, the methionine requirement level in diet was 1.43% when the specific growth rate reached peak.When the methionine levels were 1.33% and 1.62%,the crude protein content in muscles was significantly higher than that in the control group (P<0.05).There was no significant difference between crude fat and crude ash content among groups (P>0.05).The protease,amylase and lipase activities of hepatopancreas,fore intestine,middle intestine,and hind intestine increased before decreasing.When the level of methionine was 2.21%,the activity of hind intestine protease was significantly lower compared with the control group (P<0.05),while protease activities of hepatopancreas,fore intestine and middle intestine had no significant difference with the control group (P>0.05).The feed methionine level had no significant effect on activities of amylase and lipase in hepatopancreas,fore intestine,middle intestine and hind intestine (P>0.05).The activities of glumtaic pyruvic transaminase and glutamic oxalacetic transaminase decreased after initial increase. When the level of methionine was 1.62%,the activity of glumtaic pyruvic transaminase was significantly higher than that of the control group (P<0.05),and the activity of glutamic oxalacetic transaminase was significantly higher than that of the control group (P<0.05) when the levels of methionine were 1.62% and 1.92%.【Conclusion】From the growth performance,digestion and metabolism,the suitable methionine level in feed of Rhynchocypris lagowskii Dybowski was 1.33%-1.62%. |
| Key words: Rhynchocypris lagowskii Dybowski methionine digestive enzyme protein metabolism enzyme growth performance |
