不同饵料对稀有鲫生长和繁殖的影响

饵料对鱼类生长发育和繁殖具有重要影响。为了筛选稀有鲫(Gobiocypris rarus)幼鱼和成鱼阶段最适投喂方式, 实验将出膜5周末(日龄为35 day after hatching)的幼鱼随机分为5个组: A组投喂丰年虫; B组每周前6d (days)投喂丰年虫, 后1d投喂商业化微颗粒S3饲料; C组每周前3.5d投喂丰年虫, 后3.5d投喂饲料; D组每周前1d投喂丰年虫, 后6d投喂饲料; E组一直投喂饲料; 各组均采用饱食投喂策略。每2周统计生长、存活指标, 直至第21周(147 dah), 在17周(119 dah)取材用于观察性腺发育程度。在产卵后统计各组产卵量、孵化率和子代畸形率。结果显示: (1)E组存活率和特定生长率显著低于其他组(P<0.05); (2)从产卵量、孵化率和子代畸形率上看, B组产卵量显著高于其他组(P<0.05); (3)从性腺组织学上看, 不同投喂方法对精巢的成熟度无显著影响, 但投喂过丰年虫的稀有鲫卵巢发育成熟度显著优于E组。研究结果提示:适量加入丰年虫比单一投喂活饵或饲料更有利于稀有鲫的生长和繁殖。建议在标准化养殖过程中, 幼鱼和成鱼期的稀有鲫采取丰年虫与饲料投喂频次比值为6﹕1的方式最佳。     

投喂水平对长吻 仔稚鱼生长和存活的影响

以长吻(鱼危)仔鱼为实验对象, 探讨不同投喂水平对7-14日龄阶段和21-29日龄阶段的长吻(鱼危)仔稚鱼存活、生长以及鱼体组成的影响。7-14日龄阶段设计6个投喂水平, 分别为: 20、30、40、50、60和70 % IBW/d(IBW: initial body weight); 21-29日龄阶段设计6个投喂水平: 10、20、30、40、50、60 % IBW/d。实验结果表明: (1)投喂水平显著影响长吻(鱼危)仔稚鱼的存活和生长(P0.05)。7-14日龄阶段, 投喂水平为30%-60% IBW/d处理组的仔鱼存活率显著高于20%与70 % IBW/d投喂组(P0.05)。特定生长率随投喂水平的增加显著上升, 以60% IBW/d投喂组最高(P0.05)。21-29日龄期间, 10% IBW/d投喂组存活率显著低于50% IBW/d投喂组(P0.05), 特定生长率(SGR)则显著低于其他各处理组(P0.05); (2)鱼体体长体重变异系数未受投喂水平的显著影响。鱼体产出与饲料投入之比、鱼体水分含量随投喂水平升高显著下降(P0.05), 粗蛋白含量则显著上升(P0.05); 粗脂肪和粗灰分含量无显著差异; (3)分别通过存活率和投喂水平做一元二次回归、特定生长率与投喂水平做折线回归得到7-14日龄阶段的仔鱼最适投喂水平为43 % IBW/d; 通过仔鱼存活率和特定生长率与饲料投喂水平做折线回归得到21-29日龄阶段的仔鱼最适投喂水平分别为30.62% IBW/d和28.41% IBW/d。       

不同开口饵料对川陕哲罗鲑仔鱼生长和存活的影响

分别采用水丝蚓Limnodrilus sp.、丰年虫Artemia salina、鲫鱼Carassius auratus卵和2种不同配方的人工饲料饲养川陕哲罗鲑Hucho bleekeri开口仔鱼(20日龄),研究不同开口饵料对川陕哲罗鲑仔鱼生长和存活的影响。结果表明:在仔鱼开口后的0~10 d内,丰年虫投喂的川陕哲罗鲑仔鱼生长速度显著高于其他试验组,15~20 d丰年虫组仔鱼出现负增长(-0.38%),而10 d以后2个饲料组的生长速度迅速提升。在整个试验期内,水丝蚓组和鲫鱼卵组的生长较为平稳,特定生长率均介于丰年虫组和2个饲料组之间。试验结束时,丰年虫组的存活率最高,为(91.11±5.09)%,水丝蚓组的存活率最低,为(43.33±6.67)%。基于本试验的结果和川陕哲罗鲑的摄食特性,推荐最适的开口投喂方案为:0~10 d投喂丰年虫,10 d后逐步添加人工饲料进行转食。     

哲罗鱼稚鱼最佳投喂策略

为探讨哲罗鱼稚鱼的最佳投喂策略,设置了饥饿再投喂试验、饥饿再投喂恢复试验以及日投喂频率试验.结果表明: 饥饿再投喂试验中,各饥饿组未表现出补偿生长现象.但在饥饿再投喂恢复试验中,各饥饿组表现出不同程度的补偿生长,其中S_1/2组(饥饿1/2 d投喂1/2 d)体质量的增加量与对照组接近,表现出完全补偿生长.表明在哲罗鱼早期稚鱼阶段(体质量0～2 g,水温9～15.3 ℃),S_1/2是可以考虑使用的投喂方法.日投喂频率试验中,T₃组(日投喂3次)体长、体质量的增加量以及特定生长率均最高,饵料转化率也相对较高.表明在哲罗鱼后期稚鱼阶段(体质量2～21 g,水温8.8～15.5 ℃),以日投喂3次为宜.     

哲罗鱼稚鱼最佳投喂策略

为探讨哲罗鱼稚鱼的最佳投喂策略,设置了饥饿再投喂试验、饥饿再投喂恢复试验以及日投喂频率试验.结果表明: 饥饿再投喂试验中,各饥饿组未表现出补偿生长现象.但在饥饿再投喂恢复试验中,各饥饿组表现出不同程度的补偿生长,其中S_1/2组(饥饿1/2 d投喂1/2 d)体质量的增加量与对照组接近,表现出完全补偿生长.表明在哲罗鱼早期稚鱼阶段(体质量0～2 g,水温9～15.3 ℃),S_1/2是可以考虑使用的投喂方法.日投喂频率试验中,T₃组(日投喂3次)体长、体质量的增加量以及特定生长率均最高,饵料转化率也相对较高.表明在哲罗鱼后期稚鱼阶段(体质量2～21 g,水温8.8～15.5 ℃),以日投喂3次为宜.     

饥饿对银鲫血液组分和卵巢发育的影响

对银鲫 (Carassiusauratusgibelio)进行投喂、饥饿 (1～ 4周 )、饥饿投喂 (饥饿 2周再投喂 2周 )处理后 ,测定其血液组分和卵巢发育的指标。结果表明 :饥饿处理后银鲫血液中血糖、甘油三酯的含量显著降低 ;红细胞数量、血红蛋白含量和胆固醇含量先显著降低 ,随后回升到投喂组水平 ;在饥饿过程中白细胞的数量、红细胞的长短径、红细胞沉降率和总蛋白均无明显变化。饥饿投喂处理的银鲫血液中红细胞数量、甘油三酯和胆固醇含量与投喂组无差异 ,但血糖含量仍显著低于投喂组 ,而白细胞数和血红蛋白含量显著高于投喂组。饥饿 4周延缓了银鲫卵巢发育 ,其性腺成熟系数和卵径均显著低于投喂组 ;饥饿投喂组的性腺成熟系数和卵径仍显著低于投喂组。分析说明饥饿阻碍了银鲫的卵巢发育 ,而饥饿对银鲫血液组分的影响在再投喂后得到恢复。     

鳝鱼摄食黄粉虫的饵料转化效率研究

于1998～1999年初步研究了鳝鱼摄食黄粉虫幼虫的饵料转化效率。结果表明,在相同的放养密度1.5kg·m^-2下,试验条件A(水温17±3℃,2～3d换一次水,环境安静,鱼种健康),干物质转化效率平均为20.1%,能量转化效率平均为13.9%,N、P转化效率各为22.0%、28.9%。试验条件B(水温为24±4℃,约7d换一次水,鱼种品系混杂,个别鱼体质较差),干物质转化效率平均为11.3%,能量转化效率平均为7.8%,鳝鱼长期摄食黄粉虫,生长速度较慢。在生产中宜交替投喂多种活饵或配合饲料与活饵混合投喂。     

不同开口饵料对西伯利亚鲟仔鱼生长、存活和体成分的影响

分别采用水丝蚓（Limnodrilus sp.）、卤虫无节幼体（Artemia nauplii）、枝角类（Moina sp.）和人工饲料饲养西伯利亚鲟仔鱼30 d,研究不同开口饵料对西伯利亚鲟仔鱼生长、存活率和体成分的影响.结果表明：卤虫无节幼体为西伯利亚鲟最适开口饵料,仔鱼的存活率最高（96.67%）; 投喂水丝蚓组生长速度最快;而人工饲料组生长速度明显低于其他组,且成活率最低.不同开口饵料组间仔鱼体成分差异显著,人工饲料组水分含量最高,且粗蛋白和粗灰分含量最低.采用卤虫无节幼体为西伯利亚鲟仔鱼开口饵料,然后采用水丝蚓进行强化培育,能获得较好的生长速度和存活率.     

饲料颗粒长度及投喂方法对管角螺生长和水中氨氮含量的影响

以蛋白质含量40%, 脂肪含量9%的配合饲料为试验饲料, 采用单因子试验研究了饲料颗粒长度(5、10、15、20 mm)、日投喂量(3%、6%、9%、12%)和日投喂频率(每天1 次、2 次、3 次、4 次)对管角螺(Hemifusus tuba )幼螺(壳高2.37±0.03 cm)的特定生长率、饲料效率、存活率和水中氨氮含量的影响。结果表明, 饲料颗粒长度、日投喂量和日投喂频率对幼螺的存活率均无显著影响(P>0.05), 各组存活率均在95%以上, 但对幼螺特定生长率、饲料效率和水中氨氮含量均有显著影响(P<0.05), 其中饲料颗粒长度10 mm 饲料组效果最佳, 颗粒长度5 mm 组效果最差; 日投喂量为6%组效果最佳, 日投喂量为12%组效果最差; 日投喂频率为2 次·d−1 组效果最好。结果表明, 管角螺幼螺养殖以饲料颗粒长度为10 mm、日投喂频率为每天2 次、日投喂量为体重的6%为宜。     

丙氨酰-谷氨酰胺投喂方式对建鲤生长、抗氧化及免疫力的影响

以初始质量为(33.52±0.17)g建鲤鱼种为研究对象,在室内单循环养殖系统中进行8周(w)生长试验,分别配制添加0.0%(对照饲料)和0.5%(试验饲料)丙氨酰-谷氨酰胺(Ala-Gln)的等氮(35 g/kg粗蛋白)、等能(17kJ/g能量)饲料,采用5种不同的Ala-Gln投喂方式[连续8w投喂对照饲料(I,对照组);试验饲料2w交替投喂(II);前4w投喂试验饲料、后4w投喂对照饲料(III);前4w投喂对照饲料、后4w投喂试验饲料(IV);8w连续投喂试验饲料(V)],探讨Ala-Gln投喂方式对建鲤生长、抗氧化及免疫力的影响。结果表明:Ala-Gln连续投喂和不连续投喂的生长都显著高于对照组(P<0.05)。2w交替投喂的生长率显著高于4w交替和连续8w投喂试验饲料组(P<0.05),前4w投喂试验饲料且后4w投喂对照饲料的生长率要高于8w连续投喂试验饲料组(P<0.05)。后4w投喂试验饲料组和连续8w投喂试验饲料组的血清SOD显著高于对照组(P<0.05);连续8w投喂试验饲料组显著高于2w交替投喂试验饲料组和前4w投喂试验饲料组的血清SOD(P<0.05)。Ala-Gln各种投喂方式组的肝胰脏谷胱甘肽过氧化物酶(GSH-Px)都显著高于对照组(P<0.05)。后4w投喂试验饲料组和连续8w投喂试验饲料组的血清GSH-Px显著高于对照组(P<0.05)。在Ala-Gln四种投喂方式组中,除2w交替投喂组外,其他三种投喂方式组的头肾LZM都显著高于对照组(P<0.05)。后4w投喂试验饲料组和8w连续投喂试验饲料组的脾脏LZM都显著高于对照组(P<0.05)。对照组头肾NO要显著高于各投喂方式组(P<0.05)。在试验条件下,饲料中添加Ala-Gln可提高建鲤的生长、抗氧化和免疫力。不同投喂方式间亦有显著差异,从生长、抗氧化和免疫的角度,结合经济性和适用性等进行考虑,建议采用2w间隔投喂的方式。     

两种饵料条件下点篮子鱼幼鱼酶活力及其消化道菌群比较

以点篮子鱼(Siganus guttatus)幼鱼为研究对象,分别用人工饲料和浒苔(Enteromorpha prolifera)进行饲喂,采用高通量测序技术结合生化分析方法,系统对比两种饵料对点篮子鱼(Siganus guttatus)幼鱼肝脏及消化道相关酶活力和消化道菌群的影响。结果显示,浒苔组点篮子鱼幼鱼虽然生长性能低于人工饲料组,但其淀粉酶活性更高,点篮子鱼对浒苔有良好的摄食和消化能力,浒苔足以满足点篮子鱼生长的需求;此外浒苔组点篮子鱼幼鱼消化道碱性磷酸酶、超氧化物歧化酶活性均显著高于人工饲料组,表现出了更高的免疫和抗氧化能力。在两种饵料条件下,菌群多样性随消化道延伸呈上升趋势,点篮子鱼幼鱼消化道菌群组成与饵料有关,变形菌门(Proteobacteria)、厚壁菌门(Firmicutes)和拟杆菌门(Bacteroidetes)为共有优势菌门;浒苔组消化道菌群整体多样性较饲料组高,组成结构更加丰富多样,有利于鱼类的生长。研究结果表明点篮子鱼摄食浒苔具有良好的可行性基础,生态价值显著,值得深入研究与推广。     

配合饲料和鲢鱼肉对大鲵生长的比较试验

为探讨人工配合饲料和鲢鱼肉对大鲵生长、消化和抗氧化能力的影响, 试验选取初始体重为(20.99±0.15) g的大鲵幼体48尾, 随机分成2组, 每组3个重复, 每个重复8尾, 分别投喂人工配合饲料(粗蛋白55.67%, 粗脂肪6.83%)和鲢鱼肉(粗蛋白18.03%, 粗脂肪4.11%)共92d。结果显示: (1)饲料组大鲵的增重率(WGR)、特定生长率(SGR)、蛋白质沉积率(PRR)和肌肉蛋白质合成能力均显著高于鱼肉组, 饲料系数(FCR)和存活率(SR)在两个试验组之间无显著差异(P>0.05)。(2)在大鲵摄食人工配合饲料后, 全鲵粗蛋白、皮肤胶原蛋白及粗灰分含量均显著高于鱼肉组(P<0.05), 而全鲵水分、粗脂肪与肌肉的粗脂肪和粗灰分含量显著低于鱼肉组(P<0.05)。(3)饲喂鲢鱼肉的大鲵胃蛋白酶活性显著高于饲料组(P<0.05), 而两个试验组的胃H+-K+-ATP酶和肠道消化酶活性均无显著差异(P>0.05)。(4)饲喂人工配合饲料的大鲵肝脏总抗氧化能力(T-AOC)和超氧化物歧化酶(SOD)活性显著高于鱼肉组(P<0.05), 而肝脏丙二醛(MDA)含量低于鱼肉组(P<0.05), 两个试验组的肠道抗氧化指标差异不显著(P>0.05)。研究表明, 在实验条件下, 大鲵可主动摄食人工配合饲料, 而且相比于投喂新鲜鲢鱼肉, 人工配合饲料饲喂大鲵, 在提高生长性能、促进大鲵合成皮肤胶原蛋白和肝脏抗氧化能力等方面更具优势, 说明人工配合饲料可以替代新鲜饵料成为大鲵的主要饵料。     

鲜活饵料和人工配合饲料对鳜肌肉营养成分和质构特性的影响

研究以饲喂鲜活饵料为对照组,比较分析人工饲料对鳜(Siniperca chuatsi)常规营养成分、氨基酸组成及营养价值评价、脂肪酸组成和肌肉质构特性的影响。实验结果显示,摄食人工饲料组鳜肌肉蛋白质水平与鲜活饵料组无显著性差异(P>0.05),粗脂肪含量显著较高(P<0.05)。在两种饲喂模式下鳜肌肉中氨基酸评分(AAS)、必需氨基酸指数(EAAI)、化学评分(CS)和F值均无显著差异(P>0.05),但第一限制性氨基酸均为蛋氨酸+半胱氨酸(Met+Cys),该结果可为鳜人工饲料配方优化提供指导。人工饲料组鳜肌肉中饱和脂肪酸(SFA)、单不饱和脂肪酸(MUFA)和多不饱和脂肪酸(PUFA)含量均极显著高(P<0.01),其中C20﹕5(EPA)和C22﹕6(DHA)含量极显著高于鲜活饵料组,表明人工饲料可通过营养素的均衡配比以提供更优质的脂肪酸营养。人工饲料组鳜肌肉硬度、咀嚼性、胶黏性及回复性均极显著高于鲜活饵料组(P<0.01),而黏性极显著低于鲜活饵料组(P<0.01),表明人工饲料饲喂提升了鳜的肌肉质构特性。综上所述,相比于鲜活饵料组,人工饲料...     

Experimental study of enriched frozen diet on digestive enzymes and growth of juvenile cuttlefish Sepia officinalis L. (Mollusca Cephalopoda)

Hatchlings cuttlefish were reared in the laboratory from hatching until 30 days old, fed with live shrimp, frozen shrimp or fish oil-enriched frozen shrimp. Survival of cuttlefish fed with oil-enriched frozen shrimp was better than in animals receiving live shrimp. However, there was no difference with cuttlefish fed with frozen shrimp, even if survival of those receiving oil-enriched frozen shrimp was always higher all along the experiment. Lower survival in animals fed with live shrimp represented the problem of using such food and confirms the necessity to elaborate an artificial food. Utilization of artemia was detrimental to growth and induced low values of instantaneous growth rate (IGR) and conversion rate even after feeding cuttlefish with shrimp. Nevertheless, growth parameters evolutions generally corresponded to those observed by other researchers. The profile noticed at the end of the experiment is typically observed when cuttlefish acquire their adult digestive system. Main differences were observed between groups fed with live shrimp or oil-enriched frozen shrimp. Enrichment did not induce same growth as in cuttlefish receiving live prey. However, at 20 and 25 days after hatching (DAH), in cuttlefish fed with oil-enriched frozen shrimp, ration was lower for the same growth than in other groups.These data showed capacity of juvenile cuttlefish to adjust their digestive enzyme activities according to the diet and the stage of development. Indeed, chymotrypsin was strongly influenced by enrichment, while other enzymes showed difference between live and frozen preys. Trypsin exhibited regulation by diet after 20 DAH. Freezing seemed to delay development as acid phosphatases, characteristic of first stages of cuttlefish, had lower activity in cuttlefish fed with live shrimp at 10 DAH. Moreover, influence of the stage of development was strong as activities between 20 and 30 DAH were different in all groups. This was in relation with evolution of the digestive system. These data illustrated the difficulty to elaborate optimal diet as digestive system evolves.     

微颗粒饲料与冰冻桡足类对大黄鱼稚鱼生长、存活和体成分的影响(英文)

评估三种新开发的微颗粒饲料(Diet 1,Diet 2和Diet 3)、一种混合饲料(Diet 4:Diet 3和冰冻桡足类混合投喂)和冰冻桡足类(Diet 5)对25–60日龄大黄鱼稚鱼的饲喂效果。Diet 1组大黄鱼稚鱼的特定生长率(SGR,7.97%/d)和成活率(40.0%)最高,而Diet 5组稚鱼的SGR(4.15%/d)和成活率(20.4%)最低。Diet 4组稚鱼的成活率与Diet 1组差异不显著,但其SGR低于后者。从稚鱼的SGR和成活率看,三种微颗粒饲料中,Diet 1要优于Diet 2和Diet 3。各处理组中每桶稚鱼的生物量与SGR有相似的变化趋势。各微颗粒饲料组稚鱼的体蛋白含量差异不显著,低于Diet 4组,但高于Diet 5组。而微颗粒饲料组稚鱼的脂肪含量(10.6%–13.3%)均显著高于Diet 4组(7.6%)和Diet 5组(7.2%)。尽管冷冻桡足类中C20:4n–6(AA)的含量稍低于微颗粒饲料,但Diet 4和Diet 5组稚鱼的AA含量均显著高于微颗粒饲料组。Diet 4和Diet 5组稚鱼的C22:6n–3(DHA)分别高于其相应饲料中的含量。相反地,微颗粒饲料组稚鱼的C20:5n–3(EPA)低于微颗粒饲料中的含量。这些结果表明,Diet 4和Diet 5组稚鱼体内AA、DHA和EPA的沉积效率高于微颗粒饲料组。研究表明,大黄鱼稚鱼可用微颗粒饲料"断奶"。基于Diet 1优于Diet 2和Diet 3,可将其作为进一步研究的基础配方。此外,有必要对各处理组大黄鱼稚鱼消化酶和消化道的变化进行研究以综合评估微颗粒饲料的效果。     

五种鲤科鱼类的RAPD分析兼论稀有鮈鲫的系统位置

本文作者采用20个随机引物,对五种鲤科鱼类,即稀有鲫、中华细鲫、麦穗鱼、唐鱼和草鱼的基因组进行了DNA随机扩增分析（RandomAmplifiedPolymorphicDNA,即RAPD）。其目的是为了探讨稀有鲫的系统分类位置。研究结果表明在所研究的物种中,稀有鲫与中华细鲫和唐鱼有更近的亲缘关系。     

Trypsin activity and physiological aspects in larval rearing of European sea bass (Dicentrarchus labrax) using live prey and compound diets

The aim of this study was to evaluate the potential of a compound diet as a live prey substitute for feeding European sea bass larvae ( Dicentrarchus labrax L.). The effect of a commercial diet (Nippai ML feed) and live prey ( Artemia nauplii) on tryptic enzyme activity, protein content, growth (standard length) and survival rates of sea bass larvae were tested during a 27-day rearing experiment. Sea bass larvae were divided into two groups. The live food group (control group) was fed exclusively on newly hatched Artemia nauplii (Inve AF grade), the test group was fed exclusively with the compound diet from day 15 onwards. As trypsin has been demonstrated to be a useful indicator for evaluating digestibility of food and the nutritional condition of fish larvae, individual tryptic enzyme activity was determined in both feeding groups. Larvae older than 14 days after hatching and fed on live food showed a significantly higher tryptic enzyme activity than larvae fed the compound diet. A similar relationship between tryptic activity and standard length in both test groups was detected only in small larvae (standard length < 7 mm). The usefulness of proteolytic enzyme activity measurements in larval fish research, as well as its use in aquaculture nutrition research, was confirmed. Protein content, increase in length and survival rates of the sea bass larvae were additionally determined in order to evaluate an influence on the diet. The protein content of larvae fed the Artemia nauplii was higher and the growth of larvae fed the compound diet was reduced. Larval mortality was not affected by the diet given.     

Growth response of African catfish,Clarias gariepinus (B.), larvae and fingerlings fed protease‐incorporated diets

African catfish, Clarias gariepinus (B.), is one of the promising freshwater fish species in African aquaculture but the expansion of its farming needs more production of its larvae. The use of live food organisms at first feeding for larvae is still obligatory. That increases the cost of larvae production. Hence, the incorporating of exogenous enzymes especially protease in artificial microdiets may provide affordable alternatives for enhancing the larvae performance. The present study was carried out to evaluate the growth and survival of larvae or fingerlings of African catfish fed artificial diets incorporated with different protease levels. Four artificial diets were formulated and enriched with protease enzyme at levels of 0.0, 750, 1,000, and 1,250 unit/kg diet; after that diets were made into crumbles (100–200 µm diameter). After absorption of the yolk sac, diets were offered to fish larvae (3.6 ± 0.2 mg) in triplicates as a starter feed up to apparent satiation every two hours for 30 days. In another treatment, fish larvae were fed on newly hatched Artemia nauplii (2,500 Artemia/L) as a starter food. In another experiment, African catfish fingerlings (10.1 ± 1.6 g) were fed on the same diets up to satiation twice a day for 2 months. It was noticed that the dietary protease improved larval growth and survival but not as Artemia nauplii did where fish larvae fed on Artemia nauplii showed highest growth and survival followed by those fed a diet enriched with 1,250 unit/kg diet of protease. The mortality of larvae fed protease‐enriched diets as well as the control diet was occurred mostly at the first week reaching its maximum at the third week. The poor growth was observed with fish larvae fed the control diet. Meanwhile, catfish fingerlings fed protease‐enriched diets showed higher growth over those fed the control diet. The larvae survival (11.0%–41.7%) was enhanced by increasing protease levels and it was lower than that of fingerlings (95.6%–100.0%). Furthermore, protein retention and digestibility were significantly improved with protease supplementation over the control diet especially at a level of 1,000 unit/kg diet. As compared with the previous studies, live food should be used in larvae rearing for the first week after that a starter diet enriched with protease at levels of 1,250 unit/kg diet should be used. In case of fish fingerlings, the dry diets should be enriched with 1,100 unit/kg diet to improve diet digestibility and subsequently enhance their growth.     

怀头鲇早期发育阶段消化酶及碱性磷酸酶活性变化(英文)

采用动物性饵料和人工饲料培育1～10日龄怀头鲇(Silurus soldatovi)仔稚鱼,分析测定了全鱼酸性、碱性蛋白酶、淀粉酶、脂肪酶以及碱性磷酸酶的活性。结果表明:孵化后3天开口期仔鱼已具有较高的碱性蛋白酶活性,5日龄时碱性蛋白酶比活力达到较高值,8日龄时出现低值,总体变化呈波动上升趋势;酸性蛋白酶活性在1～8日龄处于较低水平,8日龄后开始迅速升高;淀粉酶活性在5日龄左右达到最高值,随后酶活性开始下降至较低水平;脂肪酶活性变化波动较大,表现为双峰型,两个峰值分别出现在3～4日龄和6～8日龄。摄食动物性饵料仔稚鱼消化酶活性和碱性磷酸酶活性均高于摄食人工饲料。在整个早期发育过程中,碱性蛋白酶比酸性蛋白酶活性高,碱性蛋白酶、淀粉酶比活力在约8日龄仔稚鱼转变期明显下降,而酸性蛋白酶活性开始迅速升高,这说明消化酶活性的变化与仔稚鱼发育过程中消化机能转换具有相关性。怀头鲇在10日龄内碱性磷酸酶活性呈上升趋势,表明怀头鲇胃肠道功能的逐步发育完善。