【作者】 文华；

【导师】 严安生；

【作者基本信息】 华中农业大学 ， 水产养殖， 2008， 博士

【摘要】 施氏鲟（Acipenser schrenckii）是目前世界上现存的27种鲟鱼之一,具有个体大、病害少、生长速度快、肉质鲜美等特点。近年来,施氏鲟养殖在我国迅速发展,已形成了较大养殖规模,产业前景广阔。但关于施氏鲟的营养与饲料研究非常有限,仅涉及蛋白质、脂肪等少数几种营养素的需求和部分脂肪源的评价,本文研究了施氏鲟幼鱼对饲料中磷、维生素A、维生素E和维生素C的需要量以及不同糖源、脂肪源和共轭亚油酸对施氏鲟幼鱼的营养生理作用,为该鱼的配合饲料配制提供依据。具体研究内容和结果如下:1.施氏鲟幼鱼对磷需要量的研究以Ca（H₂PO₄）₂·H₂O为磷源,配制含磷水平分别为0.18%（对照组）,0.40%,0.71%,0.98%,1.38%和1.66%的6组等能等氮纯化饲料,每组饲料饲喂3个重复,每个重复饲养20尾初始体质量约为4.7g的幼鱼。经过8周的饲养后,对生长、饲料效率、成活率、幼鱼肌肉常规组成及脊椎骨灰分和钙磷含量进行分析。结果表明,随饲料中磷含量的升高,鱼体增重率、饲料效率和特定生长率显著增加（P＜0.05）,直至0.98%组达最大,然后随着饲料磷含量的增加,这些指标显著降低（P＜0.05）;试验各添加组的成活率显著高于对照组（P＜0.05）,但各添加组间没有显著差异（P＞0.05）;饲料添加磷对鱼体肌肉水分、粗蛋白质和粗脂肪含量无显著影响（P＞0.05）;当饲料磷含量在0.71%～1.66%之间时,脊椎骨中灰分、钙和磷含量差异不显著（P＞0.05）,但显著高于对照组和0.40%试验组（P＜0.05）。经过折线回归分析得出,为维持施氏鲟幼鱼最佳生长和骨骼磷水平,饲料中磷的需要量为0.88%～1.00%（占干饲料）。2.施氏鲟幼鱼对维生素A需要量的研究试验以酪蛋白和脱脂豆粕为蛋白源,糊精为糖源,玉米油和豆油为脂肪源的半纯化饲料为基础饲料。试验饲料中的维生素A共设7个梯度,分别为:10（对照组）、258、510、1050、2020、4100和8300 IU/kg。每一梯度设3个重复,每个重复放养20尾初始体质量为12.09±0.22 g的施氏鲟,养殖8周,研究维生素A对施氏鲟幼鱼生长性能、肌肉组成、肝脏和肌肉中维生素A积累量、血清过氧化物歧化酶（SOD）和溶菌酶活性的影响。结果表明:用对照组饲料饲喂的试验鱼表现出厌食、游动迟缓的缺乏症状,其它各组则未出现这些症状;饲料中维生素A含量对增重率、饲料效率、肝体指数影响显著（P＜0.05）,且在1050 IU/kg组时,各值均达到最高值;肌肉成分不受维生素A含量影响;当饲料中维生素A含量在10～4100 IU/kg时,肌肉和肝脏中的维生素A含量随饲料中维生素A增加而增加,但饲料中维生素A含量超过4100IU/kg时,这些指标不再增加;血清中溶菌酶和SOD活力都随维生素A的增加而增加,在1050IU/kg组,这两种酶的活力均达最高,而高于此浓度时（＞1050IU/kg）,酶活力出现降低趋势。对饲料中维生素A含量和施氏鲟增重率进行折线回归,施氏鲟获得最佳生长时,饲料中维生素A最低需求量为923 IU/kg。3.施氏鲟幼鱼对维生素E需要量的研究以酪蛋白、明胶和白鱼粉为蛋白源,配制成7组半纯化试验饲料,饲料中维生素E添加量分别为0（对照组）、20、50、100、200、500和1000mg/kg,每一梯度设3个重复,投喂体质量为10.10±0.31g的施氏鲟幼鱼8周,考察不同维生素E添加量对幼鱼生长及组织维生素E含量的影响,并确定施氏鲟幼鱼对维生素E的需要量。结果表明,随着饲料中维生素E添加量的增加,幼鱼的增重率、饲料效率、特定生长率、存活率和肥满度显著增加（P＜0.05）,当饲料中维生素E添加量为200mg/kg时,这些指标达到最高水平,随维生素E添加量的进一步增加,其增重率、饲料效率、肥满度又显著降低（P＜0.05）,而特定生长率差异不显著（P＞0.05）;对照组幼鱼肝体指数显著高于各添加组（P＜0.05）。肌肉和肝脏中维生素E水平随饲料维生素E添加量的增加而显著上升（P＜0.05）,当添加量≥100mg/kg时,肝脏中维生素E水平无显著变化（P＞0.05）,同时当添加量≥200mg/kg时,肌肉中维生素E水平也无显著变化（P＞0.05）;对照组幼鱼肌肉中粗脂肪含量显著高于各添加组（P＜0.05）,而饲料中添加维生素E≥100mg/kg时,肌肉中粗蛋白质含量较对照组有显著提高（P＜0.05）。对特定生长率与饲料中维生素E水平进行折线回归分析得出施氏鲟幼鱼对饲料中维生素E的需要量为187.4mg/kg。4.施氏鲟幼鱼对维生素C需要量的研究以包膜维生素C为维生素C源,配制8种维生素C水平（0.1,58.2,110.4,221.8,350.2,475.6,698.4和906.2 mg/kg）的试验饲料,每一饲料设3个重复,每重复放养10尾初始体质量为7.25±0.33g施氏鲟,养殖8周。结果显示:8周试验期间,各组试验鱼没有维生素C缺乏症状出现,存活率均为100%;维生素C对施氏鲟的生长影响显著（P＜0.05）,饲料维生素C从0.1mg/kg升到110.4mg/kg时,施氏鲟的增重率和特定生长率显著升高,饲料系数显著降低,但饲料维生素C超过110.4mg/kg,施氏鲟增重率、特定生长率和饲料系数变化不显著;饲料维生素C不超过221.8mg/kg时,肝脏、肌肉中的维生素C含量和血清溶菌酶的活性随饲料维生素C含量增加而增加;血清皮质醇浓度随饲料维生素C增加而显著降低。饲料中维生素C含量对特定生长率和肝脏中维生素C含量进行折线回归法分析,维持施氏鲟幼鱼最佳生长的饲料维生素C含量为110.4mg/kg;肝脏中维生素C含量达最大时饲料维生素C需要量为239.7mg/kg。5.不同糖源对施氏鲟幼鱼生长和部分生理生化指标的影响以葡萄糖、果糖、麦芽糖、蔗糖,糊精、α-淀粉和玉米淀粉为糖源,分别配制含22%的7组等氮等能的试验饲料,每组饲料设3个平行,每个平行放养20尾初始体质量为4.70±0.08g的幼鱼,饲养8周,研究不同糖源对施氏鲟幼鱼生长性能及血糖、肝糖原和消化道内淀粉酶活性等生理生化指标的影响。结果表明:不同糖源对施氏鲟幼鱼的增重率、特定生长率和饲料效率有显著影响（P＜0.05）,各组增重率依次为糊精、α-淀粉＞葡萄糖、玉米淀粉＞麦芽糖＞蔗糖、果糖;特定生长率和饲料效率的变化规律和增重率类似;糖源对幼鱼的蛋白质和糖的消化率影响显著（P＜0.05）,各组蛋白质消化率依次为果糖＞葡萄糖、麦芽糖、糊精＞玉米淀粉＞α-淀粉,糖的消化率依次为果糖、葡萄糖＞麦芽糖＞糊精＞α-淀粉＞玉米淀粉;不同糖源对施氏鲟幼鱼肌肉中的水分、粗脂肪和灰分含量有显著影响（P＜0.05）,对粗蛋白质含量无显著影响（P＞0.05）;不同糖源对幼鱼在饱食后的不同时间段血糖和肝糖原含量影响显著（P＜0.05）;在饱食后的不同时间点内,各组的胃淀粉酶活性均为先上升后下降,瓣肠的淀粉酶活性为先升高后降低再升高后降低,十二指肠淀粉酶活性为先下降后上升再下降,各组的淀粉酶活性均受糖源的显著影响（P＜0.05）,在肝脏中未检出淀粉酶活性。以增重率和特定生长率为参考指标,施氏鲟幼鱼饲料中适宜的添加糖源为糊精和α-淀粉。6.不同脂肪源对施氏鲟幼鱼生长、血脂和体脂肪酸的影响在饲料中分别添加10%的7种不同来源的脂肪（鱼油、葵花油、牛油、猪油、菜籽油、玉米油和大豆油）,饲养初始体质量约为9.83 g的施氏鲟幼鱼8周。试验分7组,每组3个平行,每个平行20尾鱼。研究饲料中7种不同来源脂肪对施氏鲟幼鱼生长、血脂和体脂肪酸成分的影响。结果表明:增重率以大豆油组最高,达到了611.29%,葵花油组最低为451.57%,显著低于其它各组（P＜0.05）;饲料效率以葵花油组最低为86.58%,显著低于其它6组（P＜0.05）,其余6组差异不显著（P＞0.05）。肥满度、脏体指数以鱼油组最低,与其它六组差异显著（P＜0.05）;肝体指数各组间差异不显著（P＞0.05）。鱼油和大豆油两组鱼血清中胆固醇、甘油三酯和低密度脂蛋白胆固醇含量在7组中相对较低。肌肉中总n-3系多不饱和脂肪酸比例以鱼油组最高,与其它六组差异显著（P＜0.05）,总n-6系多不饱和脂肪酸比例以大豆油组为最高,鱼油组最低。综合比较,施氏鲟饲料中脂肪以添加大豆油最好,鱼油次之,葵花油最差。7.共轭亚油酸对施氏鲟幼鱼的降脂作用研究为探讨共轭亚油酸（CLA）对饲料诱导的高脂质施氏鲟的生理作用,试验分两阶段进行:第一阶段,试验鱼随机分两组,分别投喂对照组饲料和强化饲料（高糖饲料）6周,建立高脂质施氏鲟模型;第二阶段,将试验鱼随机分成对照组、高脂模型组+CLA组（在对照饲料中添加分别CLA0、0.5%、1.0%和2.0%）,试验期6周,测定CLA对饲料诱导的高脂施氏鲟生长性能、体脂和血脂水平的影响。结果表明:添加1.0%和2.0%CLA的鱼体特定生长率与对照组相比显著降低（P＜0.05）,各试验组存活率和饲料效率无显著差异（P＞0.05）;添加2.0%CLA的试验组的鱼体脂肪含量低于对照组和各添加组（P＜0.05）,但后者之间鱼体脂肪含量差异不显著（P＞0.05）,鱼体水分、蛋白质含量和肝体指数各组间无显著差异（P＞0.05）;添加CLA2.0%的试验组与对照组相比,肝脏脂肪含量显著降低（P＜0.05）,但与其它各组差异不显著（P＞0.05）;添加CLA各组的鱼体肥满度较对照组显著降低（P＜0.05）;添加1.0%和2.0%CLA试验组鱼体血清总胆固醇含量显著低于其它组（P＜0.05）,2.0%CLA组试验鱼血清高密度脂蛋白胆固醇较对照组显著降低（P＜0.05）,添加CLA的各试验组血清甘油三酯和低密度脂蛋白胆固醇含量较对照组均无显著性差异（P＞0.05）。试验得出:饲料中添加CLA对饲料诱导的高脂施氏鲟具有降低生长、减少鱼体和肝脏脂质积累以及调节血脂水平的作用,其作用效果以添加2.0%的CLA最大。更多还原

【Abstract】 Amur sturgeon, Acipenser schrenckii, is one of the 27 existing Acipenseriformes species and a large riverine species native to Amur River, and has become the most popular sturgeon species for aquaculture in China because of its rapid growth, tasty quality and relatively few problems with diseases. So far, some studies were conducted on the lipid and protein requirement and evaluation of some lipid sources for Amur sturgeon. However, little information is available on the requirements and utilizations of the fish for dietary nutrients. Hence, the present study was conducted to investigate dietary requirements of phosphorus, vitamin A, vitamin E, and vitamin C and evaluate the effects of different carbohydrate, lipid sources and conjugated linoleic acid on growth and physiological performance for juvenile sturgeon. The contents are as follows:1. Dietary phosphorus requirement of juvenile Acipenser schrenckiiSix experimental isonitrogenous and isoenergetic purified diets were formulated containing increasing contents of phosphorus （0.18%, 0.40%, 0.71%, 0.98%, 1.38% and 1.66%, respectively）. Monocalcium phosphate was used as dietary phosphorus source, casein and glutin as protein source, dextrin as carbohydrate source, and soybean oil and maize oil as lipid source, respectively. Each experimental diet was fed to triplicate groups of 20 Amur sturgeon juveniles with initial weight approximately 4.7g in 400-1 aquaria and maintained at 25.6±2.0℃for 8 weeks. The results showed that the weight gain rate, feed efficiency and specific growth rate of the juveniles increased significantly with the increasing of the dietary phosphorus level （P<0.05）. These values reached the peak when the juveniles were fed the diet supplemented with 0.98% phosphorus, and then decreased significantly with the further increases of the dietary phosphorus level （P<0.05）. The survival rate of the fish fed the control diet （0.18% phosphorus diet） was significantly lower than that of the fish fed the other diets （P<0.05）. Supplementation of dietary phosphorus had no significant effect on the muscle moisture, crude protein, or crude lipid content of the juveniles （P>0.05）. The fish fed the diets supplemented with 0.71%-1.66% dietary phosphorus had significantly higher ash, calcium, and phosphorus contents in vertebra than those fed the control diet and the 0.40% phosphorus diet （P<0.05）. Broken-line regression analyses of specific growth rate and vertebrae phosphorus against dietary phosphorus level indicated that the dietary phosphorus requirement for optimal growth and phosphorus content in vertebra of juvenile Amur sturgeon was 0.88%-1.00% of dry diet.2. Dietary vitamin A requirement of juvenile Acipenser schrenckiiThe experiment was conducted to determine the dietary vitamin A requirement of juvenile Amur sturgeon by formulating seven semipurified diets containing 10, 258, 510, 1050, 2020, 4100 and 8300 IU vitamin A （as retinol acetate） kg^-1 diet, respectively. Each experimental diet was fed to triplicate groups of 20 early juveniles with initial average weight 12.09±0.22g in 405-1 aquaria and maintained at 25.0±2.0℃for 8 weeks. Fish fed the basal diet (10 IU vitamin A kg^-1 diet) exhibited bad appetite and activity, whereas these signs were not observed in any group fed diets supplemented with vitamin A. Weight gain, feed efficiency and hepatosomatic index increased significantly with the increases of dietary vitamin A level, which reached the peak at vitamin A 1050 IU kg^-1 diet, and then decreased. The muscle chemical compositions were not affected by dietary vitamin A levels. Vitamin A concentrations in liver and muscle increased significantly as vitamin A levels increased within a range of 10-4100 IU kg^-1 diet and above this, didn’t change significantly. The activities of lysozyme activities and super oxide dismutase （SOD） in serum were the highest when the content of vitamin A was 1050 IU kg"1 diet. Either deficit or excess (>1050 IU kg^-1) of vitamin A in the diet would reduce the activities of the two enzymes. Broken-line regression analysis of weight gain against dietary vitamin A level showed that juvenile Amur sturgeon required a minimum of 923 IU vitamin A kg^-1 diet for maximal growth.3. Dietary vitamin E requirement of juvenile Acipenser schrenckiiThe effects of dietary vitamin E （dl-α-tocopheryl acetate） on growth performance and tissue vitamin E content of juvenile Amur sturgeon had been investigated. Triplicate groups of experimental fish with initial body weight （10.10±0.31）g were cultured and fed by semi-purified diets with seven levels of vitamin E supplements （0, 20, 50, 100, 200, 500 and 1000 mg/kg diet） at 10.46% dietary lipid for 8 weeks. The weight gain, feed efficiency, specific growth rate, survival rate and condition factor significantly （.P<0.05） increased concomitantly with increasing of supplemented vitamin E level and reached their peaks on the group fed with 200mg vitamin E/kg diet, respectively. With the further increase of supplemented vitamin E level, the weight gain, feed efficiency and condition factor significantly （P<0.05） decreased, whereas the specific growth rate had no significant （P>0.05） differences among treatments. Hepatosomatic index of the control group was significantly （P<0.05） higher than that of the other treated groups. The vitamin E content in liver and muscle significantly （P<0.05） increased concomitantly with increasing of supplemented vitamin E level. No significant （P>0.05） changes were found on vitamin E content in liver of groups fed with > 100 mg vitamin E/kg diets and on that in muscle of groups fed with≥200 mg vitamin E/kg diets. The crude lipid content in muscle of the control group was significantly （P<0.05） higher than that of the other treated groups, and the crude protein content in muscle of groups fed with >100mg vitamin E/kg diets were significantly （P<0.05） higher than that of the control group. The broken-line regression analysis of specific growth rates against dietary vitamin E levels suggested that the vitamin E requirement of juvenile Acipenser schrendkii for optimal growth might be 187.4 mg/kg diet.4. Dietary vitamin C requirement of juvenile Acipenser schrenckiAn 8 weeks growth experiment was conducted to determine the effects of dietary vitamin C on survival, growth, tissue ascorbic acid content, activity of serum lysozyme and serum cortisol concentration of Amur sturgeon with initial weight of 7.25±0.33g. Eight practical diets were formulated to contain 0.1, 58.2, 110.4, 221.8, 350.2, 475.6, 698.4 and 906.2 mg ascorbic acid equivalent kg-1 diet, supplied as enveloped ascorbic acid. Each diet was fed to triplicate groups of fish in aquarium, and each aquarium was stocked with 10 fish. Fish were fed four times daily to apparent satiation for 8 weeks. The water temperature fluctuated from 19.5 to 25.5 during the experimental period. The results showed that: No gross deficiency signs were observed in any of experimental fish. Survival rate was not significantly affected by the dietary vitamin C （P>0.05）. Weight gain rate （from 514.46 to 680.31%）, special growth rate （from 3.24 to 3.67 % day-1） and feed conversion ratio （from 0.85 to 0.70） were significantly affected by the dietary vitamin C （P<0.05）. The vitamin C contents in liver and muscle positively correlated with the vitamin C in diets. The activities of serum lysozyme significantly increased with increasing dietary vitamin C, while the serum cortisol content significantly decreased. The Broken-line regression analysis showed the breakpoints were at 110.4 mg kg-1 based on maximal special growth rate, 279.4mg kg-1 on liver maximum storage of ascorbic acid.5. Effects of different carbohydrate sources on growth, some physiological and biochemical indexes of juvenile Acipenser schrenckiJuvenile Amur sturgeon were fed with 7 groups of isonitrogenous and isoenergetic diets containing 22% glucose, fructose, maltose, sucrose, dextrin,α-starch and corn starch respectively, for 8w to study the effects of differents dietary carbohydrate sources on growth, plasma glucose, liver glycogen concentration and the amylase activity of alimentary tract of juvenile Amur sturgeon. Each group had 3 replicates, and one replicate contained 20 fish （mean weight, 4.70±0.08g）. The results showed: Weight gain rate （WG）, specific growth rate （SGR） and feed efficiency （FE） of sturgeon were significantly （P < 0.05） affected by the different dietary carbohydrate sources. The effect of different dietary carbohydrate sources on the WG was dextrin,α-starch > glucose, corn starch > maltose > sucrose, fructose; SGR and FE had similar show to WG. Digestibility of sturgeon was significantly （P<0.05） affected by feeding different carbohydrate sources, on carbohydrate digestibility was glucose, fructose > maltose > dextrin >α-starch > corn starch; on protein digestibility was fructose > glucose, maltose, dextrin > corn starch >α-starch. Moisture, crude ash and crude lipid of muscle of sturgeon were significantly （P < 0.05） affected by the different dietary carbohydrate sources, but crude protein had no significantly difference （P>0.05）. Plasma glucose and liver glycogen concentration of sturgeon were significantly （P<0.05） affected by the different dietary carbohydrate sources in different period after satiation. In different period after satiation, in stomach, amylase activity increased first and then decreased; in duodenum, the activity droped at first, then performed as same as in stomach; in intestinal valve, the activity increased at first then decreased, and performed again; the amylase activity of alimentary tract was significantly （P<0.05） affected by feeding different carbohydrate sources. In liver, no amylase activity had been detected. According to WG and SGR, the appropriate carbohydrate in diet of Amur sturgeon was dextrin andα-starch. 6. Effects of dietary lipids on the performance of growth, serum lipids and tissue fatty acid composition of juvenile Acipenser schrenckiAn 8-week growth experiment was conducted to test seven lipids on juvenile Amur sturgeon. The fish （initial body weight 9.83 g） in triplicate groups were fed with 10 % of each lipid included into basic diet in fiberglass tanks. Seven dietary lipids were fish oil, sunflower oil, tallow, lard oil, colza oil, corn oil and soybean oil repectively. The results showed that: The weight gain rate of fish fed soybean oil diet was the highest （611.29%） and group of sunflower oil was the lowest （451.57%） which were significantly lower than other groups. The lowest feed efficiency was also observed at group of sunflower oil which had significant difference from the other 6 groups. Fish fed with fish oil had the lowest condition factor and gut somatic index which were significantly lower than those of the other groups （P<0.05）.There was no significant difference in hepatopancreas somatic index of the fish. The concentrations of cholesterol, triglyceride and low density lipoprotein cholesterol in serum of group fish oil and soybean oil were comparatively low in the 7 groups. The ratios of total n-3 polyunsaturated fatty acids in lipid of muscle of fish fed fish oil were significantly higher than those of fish fed other lipids （P<0.05）, while the highest and the lowest ratios of total n-6 polyunsaturated fatty acids were observed in the fish fed soybean oil and fish oil, respectively. Compared comprehensively, the best dietary lipid to juvenile Amur sturgeon was soybean oil, the next in order was fish oil, while sunflower oil was minimal.7. Study on effects of conjugated linoleic acid on weight losing and lipid lowering of juvenile Acipenser schrenckiThe experiment was conducted to investigate the effects of dietary conjugated linoleic acid （CLA） on growth, body lipid level and serum lipids in juvenile Amur sturgeon. Groups of fish were fed controlled and enriched diets for 6 weeks to gaint high-lipid groups. Then, juvenile Amur sturgeons were randomly divided into control group and high-lipid +CLA groups （0, 0.5, 1.0, 2.0% CLA/control diet respectively）. At the end of experiment, SGR decreased significantly by 1.0% and 2.0% CLA supplement （P<0.05）. CLA had no effect on survival rate and FCR; CLA addition reduced condition factor among treatments. No differences were detected in body moisture, protein, and HSI, The lipid contents in liver reduced at 2.0% CLA feeding; TC decreased in serum when the fish were fed 1.0% and 2.0% CLA, and HDL-C decreased when supplied with 2.0% CLA, while, TG and LDL-C were silimar among treatments. In conclusion, the fortified CLA was effective in lowering growth, body lipid and blood lipids of juvenile Amur sturgeon, and the maximum effect on these appeared at the 2.0% CLA supplemented group.更多还原