池塘和稻田养殖模式对泥鳅营养品质的影响

为探究不同养殖模式对台湾泥鳅(Paramisgurnus dabryanus ssp.)和泥鳅(Misgurnus anguillicaudatus)营养品质的影响,本研究分析了池塘和稻田养殖模式下,台湾泥鳅和泥鳅的形体性状、营养成分和品质差异,并探讨了这些指标间的相关性。结果显示,台湾泥鳅的肥满度显著高于泥鳅,其中,池塘养殖模式下的台湾泥鳅(P. dabryanus ssp. pond-cultivated, PPOC)肥满度(1.00±0.01)显著高于池塘养殖模式下的泥鳅(M. anguillicaudatus pond-cultivated, MPOC) (0.50±0.01) (P<0.05)。泥鳅的粗蛋白含量显著高于台湾泥鳅(P<0.05),而粗脂肪含量显著低于台湾泥鳅(P<0.05),其中,稻田养殖模式下的泥鳅(M. anguillicaudatus paddy-cultivated, MPAC)粗蛋白含量最高,达(21.09±0.57)%。除内聚性外,台湾泥鳅的质构特性显著高于泥鳅(P<0.05);养殖模式对2种泥鳅的形体性状有显著影响,PPOC肥满度显著高于稻田养殖模式下的台湾泥鳅(P. dabryanus ssp. paddy-cultivated, PPAC) (P<0.05),MPOC肥满度显著低于MPAC (P<0.05)。池塘养殖模式下2种泥鳅的致动脉粥样化指数和血栓形成指数显著低于稻田养殖的相同品种(P<0.05),硬度(PPOC)>硬度(PPAC),弹性(MPOC)<弹性(MPAC) (P<0.05),稻田养殖模式的2种泥鳅的谷氨酸、精氨酸、组氨酸、缬氨酸和甲硫氨酸高于池塘模式的相同品种(TAV>1)。主成分分析结果显示,形体性状与营养品质密切相关,肥满度与体长体高比呈负相关(–0.996),与质构特征、粗脂肪含量呈正相关,与水分、灰分、粗蛋白含量呈负相关。基于肥满度、质构等指标,PPOC最适合作为泥鳅加工原料。     

工厂化养殖美洲鲥幼鱼的生长特性及消化酶活性变化

在工厂化养殖条件下,将初始体长为(54.04±6.07)mm、体质量为(2.03±0.75)g的4 000尾美洲鲥幼鱼放在有效体积约300 m³的养殖池中饲养84 d,研究美洲鲥幼鱼养殖过程中的生长特性及生长过程中消化酶活力的变化特点。结果显示:美洲鲥体长(L)、体质量(W)均与养殖时长(t)呈指数相关(L＝56.568e0.008 8t,W＝2.463 3e0.027 4t),体长与体质量呈幂函数相关(W＝7×10-6L3.158 2),试验期间美洲鲥幼鱼的生长类型为等速生长；总体上,肥满度随着幼鱼的生长发育而明显提高,试验初期(养殖14 d时)显著提高,之后有所降低,在42 d时显著下降(P＜0.05),之后幼鱼的肥满度保持着较快的增长,随着时间的推移显著提高(P＜0.05),并在试验结束时达到最高值。美洲鲥幼鱼胃蛋白酶活力随着幼鱼的生长显著升高(P＜0.05)；幽门盲囊的淀粉酶活力随着幼鱼生长显著下降(P＜0.05),而蛋白酶和脂肪酶活力总体呈升高趋势(P＜0.05)；肠道中淀粉酶的活力随着幼鱼生长而显著降低(P＜0.05),蛋白酶和脂肪酶活力总体呈上升趋势,最大值均出现在第84天(P＜0.05)。研究结果表明,工厂化养殖美洲鲥幼鱼的生长类型为等速生长,本试验的养殖条件适宜美洲鲥幼鱼生长；养殖过程中应根据消化酶的变化规律,适时调整饲料中营养成分的含量或添加生物酶制剂,以提高饲料的利用效率,提高养殖效益。     

传统池塘和“跑道”养殖黄金鲫的营养组成分析与评价

为研究不同养殖模式对黄金鲫(Carassius auratus)营养组成和品质的影响,以传统池塘精养和采用池塘内循环流水“跑道”模式养成的黄金鲫为研究对象,分析比较了两种养殖模式下黄金鲫肌肉营养成分、质构和风味物质等指标。结果显示,“跑道”组黄金鲫背肌的粗脂肪含量显著低于池塘组,而粗灰分含量显著高于池塘组(P＜0.05);“跑道”组黄金鲫肌肉的硬度、粘附性和黏性等质构指标与池塘组相比显著提升(P＜0.05)。两种模式下养成的黄金鲫,其肌肉的氨基酸组成无显著差异(P＞0.05),且必需氨基酸评分均高于FAO/WHO的标准。“跑道”组黄金鲫肌肉中不饱和脂肪酸、单不饱和脂肪酸和多不饱和脂肪酸占总脂肪酸的比例均显著高于池塘组,而饱和脂肪酸占比显著低于池塘组(P＜0.05)。“跑道”组黄金鲫肌肉中部分挥发性物质,如壬醛、1-辛烯-3-醇的含量也低于池塘组。分析比较结果表明,采用池塘内循环流水“跑道”养殖模式可以在一定程度上提升黄金鲫的营养品质。     

不同养殖模式的凡纳滨对虾品质的比较

仪器分析法(营养成份分析和质构分析)与感官评价法有机结合,以对虾口感为主要考核指标,建立对虾品质鉴定体系,并以此法对无公害海水养殖、传统海水养殖及传统淡水养殖对虾3种不同养殖模式下生产的对虾品质进行比较.结果表明:3种对虾的机体营养成分组成差异不大,只有无公害虾肌苷酸含量明显高于其余两组,达2.76 mg·g-1.氨基酸分析中表明:无公害海水养殖对虾的必需氨基酸、非必需氨基酸、鲜味氨基酸及氨基酸总量等指标优于其余样品;无公害虾的感官指标基本上与海水虾相似,3种虾的色泽和气味指标差异不明显(P＞0.05),无公害虾的滋味及口感均比其它两组对照好;多汁性指标则以淡水虾最佳.在质构分析方面,3种虾硬度指标差异显著(P＜0.05),无公害虾与海水虾在肌肉的弹性及咀嚼性无显著性差异(P＞0.05),与淡水虾差异显著(P＜0.05),其结果与感官评价基本一致.本文全面比较3种对虾品质上差异,揭示对虾口感差异内在因素,为对虾品质评价提供了方法和手段.     

牡蛎壳粉缓释剂对魁蚶(Scapharca broughtonii)生长的影响

2015年4月6日-10月26日,在桑沟湾海区现场研究了牡蛎壳粉缓释剂(Careshell)对魁蚶(Scapharca broughtonii)生长和存活的影响.按照缓释剂的重量比设置4个处理组,其中,魁蚶的初始体重均为160g/组,缓释剂的重量分别为0(对照组C0)、80 g(C1组)、160 g(C2组)和320 g(C3组).实验共进行200 d,每40 d测量各实验组魁蚶的生长参数(壳长、壳宽、壳高、湿重),计录死亡个体数,计算不同阶段(40 d间隔)魁蚶的特定生长率(SGR)及死亡率.结果显示,C3组魁蚶各生长参数显著高于C0组(P＜0.05),但与C1、C2组差异不显著(P＞0.05).经过200 d的养殖实验,C3组壳长、壳宽、壳高和湿重的特定生长率分别为(0.34±0.01)％/d、(0.46±0.02)％/d、(0.39±0.01)％/d、(1.11 ±0.002)％/d,均极显著高于C0组(P＜0.01),平均增加了17.9％、20.3％、18.1％、16.7％.C3组死亡率为(19.6±5.6)％,低于C0组的(26.1±2.5)％,但差异不显著(P＞0.05).     

硝化型和光合自养型生物絮团对泥鳅生长、肠道菌群和水体微生物群落结构的影响

为了解硝化型和光合自养型生物絮团对于泥鳅(Misgurnus anguillicaudatus)的养殖效果, 设置清水组(CW 组)、硝化组(BFT 组)和光合自养组(ABFT 组)生物絮团养殖泥鳅 45 d, 比较泥鳅的生长和消化酶活性、两类絮团的营养组成情况, 以及养殖水体和泥鳅肠道微生物的群落结构。结果显示, BFT 组和 ABFT 组的饲料转化率、特定生长率和末均重没有显著性差异(P＞0.05)。与 CW 组相比, 两实验组的饲料转化率显著降低; BFT 组的终末密度与 CW 组相比没有显著性差异(P＞0.05)。与 CW 组相比, BFT 组和 ABFT 组生物絮团可以提供(36.69±1.17)%和 (40.20±1.05)%的粗蛋白; 与 BFT 组相比, ABFT 组的生物絮团粗脂肪含量显著提高(P＜0.05), 并且促进脂肪酸由饱和向不饱和转化。ABFT 的泥鳅胰蛋白酶和脂肪酶的活性显著高于另外两组(P＜0.05)。微生物群落分析表明, 添加藻类对成熟生物絮团 Alpha 多样性指数、群落门水平和属水平没有显著影响。泥鳅摄食生物絮团会导致肠道菌群 sobs 指数显著降低。BFT 组肠道的优势菌群为变形菌门(Proteobacteria)、放线菌门(Actinobacteriota)和绿弯菌门 (Chloroflexi); ABFT 组为变形菌门和蓝藻门(Cyanobacteria)。属水平上, ABFT 组检测到高水平的气单胞菌属 (Aeromonas)。本研究表明, 硝化型和光合自养型生物絮团养殖均适合作为泥鳅绿色健康养殖的新模式。     

不同养殖模式对尼罗罗非鱼（Oreochromis niloticus）生长、免疫性能及水质的影响

为探讨循环水养殖模式(RAS组)和池塘养殖模式(池塘组)对尼罗罗非鱼生长、免疫性能及水质影响的变化规律,开展了为期8周的养殖试验。结果表明：(1)RAS组中鱼体增重率(WGR)(597.36±169.79)显著高于池塘组(470.98±142.99)(P < 0.05),但饲料转化率(FCE)(1.17±0.02)却显著低于池塘养殖系统(1.47±0.03)(P < 0.05)。特定生长率(SGR)和肥满度(CF)也高于池塘养殖系统,但差异不显著(P > 0.05);(2)在第4周和第8周分别测定了鱼体胃和肠中消化酶活性显示,第4周时,RAS组中肠蛋白酶活性值(1387.56±278.43)显著高于池塘组(1129.99±382.67)(P < 0.05);第8周时,肠脂肪酶活性(18.11±4.28)显著高于池塘组(12.89±8.00)(P < 0.05);(3)在第4周和第8周分别测定了鱼体肝胰脏、头肾和血清中碱性磷酸酶(ALP)、溶菌酶 (LSZ)和总超氧化物歧化酶(T-SOD)活性,显示整体上RAS组免疫性能低于池塘组;(4)每周测定水体氨态氮和亚硝态氮含量显示,RAS组氨态氮维持在0.0067 ~ 0.0212 mg / L区间内,亚硝态氮含量位于0.0027 ~ 0.0087 mg / L范围内,均低于池塘组。     

稻田和池塘养殖禾花鲤肌肉营养与品质分析

为评估不同养殖环境对禾花鲤(Cyprinus carpio)肌肉营养与品质的影响,采用国标法检测稻田和池塘2种养殖环境下禾花鲤肌肉常规营养成分、质构特性、氨基酸和脂肪酸组成。结果显示,池塘组禾花鲤肌肉粗蛋白和粗脂肪含量显著高于稻田组(P<0.05),水分含量显著低于稻田组(P<0.05),灰分含量2组差异不显著(P>0.05);池塘组肌肉粘性显著高于稻田组(P<0.05),内聚性和剪切力显著低于稻田组(P<0.05),其他质构指标2组间差异不显著(P>0.05);肌肉氨基酸测定结果显示,池塘组氨基酸总量(?TAA)、鲜味氨基酸(DAA)、必需氨基酸(EAA)、非必需氨基酸(NEAA)显著高于稻田组(P<0.05),?EAA/TAA和?EAA/NEAA显著低于稻田组(P<0.05),2组禾花鲤必需氨基酸构成比例均符合FAO/WHO标准;在鲜味氨基酸含量方面,池塘组主要的4种呈味氨基酸含量均显著高于稻田组(P<0.05)。根据氨基酸评分(AAS)和化学评分(CS)标准,2组禾花鲤肌肉第一、二限制性氨基酸均分别为色氨酸(Trp)和缬氨酸(Val);在脂肪酸测定结果中显示,池塘组单不饱和脂肪酸(∑MUFA)含量显著高于稻田组(P<0.05),但多不饱和脂肪酸(∑PUFA)、EPA+DHA和∑n-3PUFA/ ∑n-6PUFA显著低于稻田组(P<0.05)。综上所述,池塘和稻田养殖条件下,禾花鲤均为优质的蛋白质来源,但不同养殖环境对禾花鲤肌肉营养与品质有显著影响。从常规营养成分、氨基酸评分方面看,池塘养殖条件下禾花鲤肌肉营养价值更高;从脂肪酸角度来看,稻田养殖禾花鲤肌肉具有较高的EPA+DHA含量以及n-3/n-6多不饱和脂肪酸比例,更适合高血脂和心血管疾病等患者食用,从质构性来看,稻田养殖环境下禾花鲤肌肉更具嚼劲。     

鲤、鲇及草鱼肌肉理化特性的比较研究

以杂食性的鲤(Cyprinus carpio)、肉食性的鲇(Silurus asotus)和草食性的草鱼(Ctenopharyngodon idellus)为研究对象,测定了2龄鱼的背部、胸部、腹部和尾部肌肉的pH值、滴水损失、熟肉率、失水率、胶原蛋白含量及剪切值等理化指标,对3种鱼不同部位的肌肉理化特性进行了比较,初步探讨了鱼肉理化特性与食性的关系.结果表明,鲤、鲇及草鱼肌肉的pH值为6.2 ～6.7,3种鱼肌肉间pH值无显著差异(P＞0.05);鲤、鲇及草鱼各个部位肌肉之间以及3种鱼之间的肌肉滴水损失率均无显著差异(P＞0.05);每种鱼各部位肌肉之间的熟肉率无显著差异(P＞0.05),熟肉率表现为:草鱼＞鲤＞鲇(P＜0.05);同一种鱼不同部位肌肉的失水率无显著差异(P＞0.05),3种鱼之间的失水率表现为:鲇＞鲤＞草鱼(P＜0.05);同一种鱼不同部位肌肉的胶原蛋白差异显著(P＜0.05),3种鱼之间差异也显著,鲇＞鲤＞草鱼(P＜0.05);同一种鱼不同部位之间的剪切值差异显著(P＜0.05),3种鱼之间的剪切值表现为:鲇＞鲤＞草鱼(P＜0.05).综合比较可见,淡水经济鱼类的肌肉理化特性与其食性存在一定的相关性,肉食性鱼的嫩度偏低,剪切值大,胶原蛋白含量高,失水率和滴水损失较大,保水能力也相对较差,且同一种鱼各个部位间的肉质理化特性也存在一定差异.     

不同体色鲤的生长、酪氨酸酶活性、黑色素含量及基因表达比较

‘福瑞鲤 2 号’鲤(Cyprinus carpio)在繁育过程中会出现橘红色个体, 为了探讨鲤体色分化与生长性能的相关性, 利用‘福瑞鲤 2 号’构建具有青灰色和橘红色个体的家系, 并对其生长性状、酪氨酸酶活性、黑色素含量、黑色素合成通路(ko04916)及生长激素合成、释放和效应通路(ko04935)相关基因的表达水平进行比较。结果显示, 青灰色组 3 月龄体重、体长、体高和体厚均极显著大于橘红色组(P＜0.01), 其体长/体高显著大于橘红色组(P＜0.05)。青灰色组皮肤中酪氨酸酶活性和黑色素含量均显著高于橘红色组(P＜0.05)。与青灰色组相比, dct、mc1r、mitfb、tyr 和 tyrp1 等 12 个黑色素合成通路(ko04916)基因在橘红色组皮肤中的表达量显著(P＜0.05)或极显著降低(P＜0.01), 且 gh、ghr 和 igf2 等 6 个生长激素合成、释放和效应通路(ko04935)基因在橘红色组肌肉中的表达量也显著(P＜0.05)或极显著 (P＜0.01)降低。此外, 代谢通路内基因呈现共表达模式, 代谢通路间共有基因在组织间呈现相似表达趋势。研究表明, 鲤体色变异与黑色素合成通路存在密切关系, 且不同体色个体表现出生长差异, 推测与体色和生长调控通路间存在相同基因有关。     

盐度对大鳞副泥鳅抗氧化酶及组织结构的影响

为研究盐度对大鳞副泥鳅（Paramisgurnusdabryanus）Na+-K+-ATP酶（NKA）、抗氧化酶活性及组织结构的影响,试验设置4、8、12共3个盐度组和一个淡水组（对照）,以全长（17.60±0.69）cm,体质量（35.51±5.30）g的大鳞副泥鳅进行14 d胁迫试验。结果表明：盐度升高使鳃Na+-K+-ATP酶活力上升,第7 d 时3个试验组Na+-K+-ATP酶活性均达到峰值且盐度8和12组显著高于淡水组（P<0.05）。肝脏SOD和CAT活性均表现为先上升后下降的趋势,且分别于胁迫12 h和2 d时达到最大值;3个盐度组的GSH-PX酶活性在6 h和12 h均有所升高,且盐度12组显著高于淡水组（P<0.05）。盐度4、8和12组肝脏MDA含量分别在第1 d和7 d达到最大值且显著高于淡水组（P<0.05）。组织切片结果显示,盐度12组的鳃小片变窄,鳃小片间距变大,泌氯细胞数量增多;肝细胞空泡化严重,血窦扩张范围增大,并出现细胞轮廓模糊、细胞核偏移、细胞核溶解。上述结果表明,盐度胁迫对大鳞副泥鳅的Na+-K+-ATP酶、抗氧化酶活性具有显著的诱导作用,并对其鳃和肝组织造成损伤。     

黄条鰤仔稚幼鱼消化酶活性变化研究

为了解黄条鰤(Seriola aureovittata)早期发育阶段的消化生理特性,测定了黄条鰤胚胎、仔稚幼鱼阶段脂肪酶、淀粉酶、胰蛋白酶和碱性磷酸酶活性变化。结果显示,在黄条鰤仔鱼出膜前胚胎阶段,即能检测到脂肪酶、淀粉酶和碱性磷酸酶活性;初孵仔鱼体内(1 d)初次检测出胰蛋白酶的活性。脂肪酶和碱性磷酸酶比活力在仔鱼孵化后迅速增强(P<0.05),在4 d开口时,2种酶比活力达最高值;淀粉酶比活力在7 d时达最大值;胰蛋白酶比活力在仔鱼阶段缓慢上升,15 d时比活力最大。稚鱼阶段内脏团中脂肪酶、碱性磷酸酶和胰蛋白酶活性基本维持稳定,幼鱼阶段内脏团脂肪酶、碱性磷酸酶和胰蛋白酶活性都呈现上升趋势;稚鱼和幼鱼阶段内脏团中淀粉酶活性下降并基本稳定于较低水平。研究表明,黄条鰤仔稚幼鱼发育过程中,各种消化酶活性变化明显,且与其发育阶段和食性密切相关。在尚未摄食饵料的早期仔鱼体内已存在消化酶,认为其是母源传递而来,不是由外源性饵料所致;幼鱼阶段内脏团脂肪酶、碱性磷酸酶和胰蛋白酶比活力明显提高,这反映出随苗种生长发育,其肠道结构和消化机能逐渐完善,并且对脂肪、蛋白质的需求逐渐增强。     

Effects of genetic strain and holding facility on the characteristics of alkaline phosphatase and brush border enzymes in silver perch (Bidyanus bidyanus)

The activity of the enzymes located in the digestive tract (pyloric caeca and intestine) in two strains and F₁ crosses of the Australian freshwater fish silver perch [Murray River (M) and Cataract Dam (C)] was evaluated. The effect of the fish holding system (cages or ponds) on the activity of alkaline phosphatase (AP) and the brush border enzymes: maltase, leucine amino peptidase (LAP) and γ‐glutamyl transferase (γ‐GT) was examined. The enzymatic activity was tested in three intestinal sections: the pyloric caeca, upper and lower intestine. All the tested enzyme activities were influenced by an interaction between the intestinal section and the strain or cross of silver perch. For fish maintained in ponds, there were two distinct enzymatic activity patterns, one for the pure strains (C × C and M × M) and one for the crosses (C × M and M × C). Significantly higher (P<0.05) enzymatic activities of the crosses compared with the pure strains were particularly noticeable in the pyloric caeca. In fish held in cages, there was a significantly higher (P<0.05) enzymatic activity in the pyloric caeca of the C × C strain. The total enzymatic activities in the fish reared in the ponds were significantly higher (P<0.05) than those in the fish held in cages. The results of the present investigation confirm that the different genetic background of the silver perch in the Murray River and in the Cataract Dam influences the activity of the brush border digestive enzymes. This activity also varies between maintenance systems.     

Effects of exogenous non-starch polysaccharide-degrading enzymes in diets containing <Emphasis Type="Italic">Gracilaria lemaneiformis</Emphasis> on white-spotted snapper <Emphasis Type="Italic">Lutjanus stellatus</Emphasis> Akazaki

A feeding experiment was conducted to investigate the effects of exogenous non-starch polysaccharide (NSP)-degrading enzymes in diets containing Gracilaria lemaneiformis (GL) on growth performance and digestive enzyme activities of white-spotted snapper Lutjanus stellatus Akazaki (initial mass 8.0 ± 0.1 g). A basal diet (D0) containing a mixed protein source (fish meal, soybean meal and GL meal) was used as the control. Two diets supplemented with 0.5 g (D1) and 1 g (D2) exogenous NSP-degrading enzymes per kilogram of diet were formulated. Each diet was assigned to triplicate groups of fish in a total of nine floating sea cages (270 fish, 30 fish per cage). After a 60-day feeding trail, significantly higher weight gain, specific growth ratio and feed efficiency ratio were observed in fish fed D2 diet compared to those of control (P < 0.05). Body lipid, moisture and ash contents were not significantly affected by NSP-degrading enzyme supplementation, but significantly higher protein content was noticed in fish fed D2 diet compared to that of control (P < 0.05). The amylase activity in the stomach and intestine was significantly higher in fish fed D2 diet (P < 0.05), but no significant differences were observed in pepsin and lipase activities in the stomach or trypsin and lipase activities in the intestine between all treatments. The results suggested that addition of 1 g kg^?1 NSP-degrading enzymes in diet could efficiently improve seaweed feed utilization and growth performance of white-spotted snapper fish.     

复合益生菌制剂对大西洋鲑(Salmo salar)生长、消化酶和非特异性免疫指标的影响

选取体质健康、均重为(180±28)g的大西洋鲑(Salmo salar) 420尾,随机分成4组(对照组和3个不同菌剂水平的实验组),每组3个重复,每个重复35尾.对照组投喂基础饲料,实验组分别投喂添加1％、3％和5％芽孢杆菌和酵母菌复合益生菌制剂(BSCP)的基础饲料42 d.结果发现,大西洋鲑投喂1％-5％的BSCP后生长性能得到明显改善,增重率显著升高(P＜0.05),饵料系数和死亡率显著降低(P＜0.05);饲料蛋白质的表观消化率呈升高的趋势,5％组蛋白质消化率具有显著性差异(P＜0.05),但其脂肪表观消化率显著降低(P＜0.05);实验组肠道和肝脏蛋白酶和脂肪酶活性有不同程度的升高,但其中5％组肝脏脂肪酶活性显著降低(P＜0.05);实验组肝脏免疫指标表现出不同程度的改善,但其血清免疫指标无明显变化,仅中高剂量组SOD活性显著降低(P＜0.05).结果表明,BSCP可以显著提高大西洋鲑的生长性能,提高部分消化酶活性和蛋白质的消化率,并在一定程度上促进大西洋鲑的非特异性免疫能力,其饲料中适宜添加水平为3％.     

Growth and digestive enzymes of Macrobrachium rosenbergii juveniles: effect of different stocktypes and dietary protein levels under a similar culture environment

A feeding trial was conducted to study the effect of dietary protein (DP) levels on the growth and digestive enzyme activities of different wild stocks of Macrobrachium rosenbergii juveniles. Wild juveniles of M. rosenbergii were collected from the west coast of India, Gujarat (G), Maharashtra (M) and from the east coast of India, Andhra Pradesh (A), and raised in culture ponds of 200 m² at 1 juvenile m^?2. All the animals were tagged individually with Elastomer tags of a particular colour assigned to their respective stock and acclimatized for 7 days before being released into the pond at a ratio of 70:65:65 (A:M:G). Each of the two feeds, the first with 27% DP, termed the suboptimum level (S), and the second 32% DP, termed the optimum level (O), was fed in duplicate ponds at 6% of the body mass for the first 30 days and 4% for the last 30 days. The average weight of stocked prawn, respectively, in O DP and S DP fed ponds was 0.90 ± 0.04 and 1.06 ± 0.08 g for the G stock, 0.80 ± 0.07 and 1.01 ± 0.1 g for the M stock and 3.06 ± 0.13 and 3.10 ± 0.23 g for the A stock. Both the protein level and the stock type had a significant (P<0.05) effect on the weight gain% of the prawn. There was an approximate 95% change in weight gain with a DP change. Similarly, G and M stocks exhibited significantly higher (P<0.05) growth rates of approximately 90% than the A stock, although no difference was noted between the G and the M stocks. However, for protein × stock (interaction) levels, there was no significant difference (P>0.05) among the groups. Although insignificant, the survival rates among the different stocks varied from 56% to 77%. Optimum protein level showed a significant increase (P<0.05) in the specific growth rate (SGR). Feed conversion ratio, feed efficiency ratio, protein efficiency ratio and net protein utilization were not affected either due to DP, stock type or their interaction. The O × A group exhibited the maximum variation in body weight. Digestive enzyme activities were similar in all the groups, but enzymes for phospho‐monoesterase were significantly higher (P<0.05) at O DP. Both the G and the M stock showed a significantly higher (P<0.05) alkaline phosphatase activity while acid phosphatase activity was significantly higher (P<0.05) in the M stock only. Overall, the G and M stocks showed higher growth responses compared with the A stock.     

添加不同碳源对零换水养殖系统中团头鲂鱼种生长、肠道生化指标和水质的影响

为探究添加不同碳源物质所形成的生物絮团对团头鲂鱼种生长、消化酶以及抗氧化酶活性的影响,设计5个不同碳源物质的添加组[淀粉组、葡萄糖组、蔗糖组、甜蜜素组和复合碳源组(葡萄糖∶淀粉=1∶1)],其中淀粉组为对照组,每个碳源添加组设置3个重复。每个水泥池投放团头鲂鱼种20尾,初始体质量为(36.74±0.82)g,实验期为8周。结果发现:(1)形成的生物絮团可以有效地调节水质,降低水体中的氨氮和亚硝酸盐氮水平;(2)与对照组相比,葡萄糖组团头鲂鱼种的鱼体末质量显著提高23.1%,增重率显著提高39.4%,特定生长率也显著提高23.6%,饲料系数显著降低28.1%,但存活率并没有显著差异;(3)肠道组织光镜观察表明,团头鲂鱼种肠道单层柱状上皮附近存在未消化的生物絮团;(4)添加不同碳源形成的生物絮团对团头鲂鱼种体成分没有显著的影响;(5)复合碳源组的肠道总蛋白酶的活性(3.64±0.53)U/mg显著高于对照组275.3%,淀粉酶活性显著高于对照组(淀粉组)289.2%、葡萄糖组166.7%和蔗糖组860%;(6)葡萄糖组的团头鲂超氧化物歧化酶(SOD)活性为(238.67±13.63)U/mg,显著高于对照组的SOD活性72.5%,葡萄糖组团头鲂的过氧化氢酶(CAT)酶活性为(192.31±17.06)U/mg,显著高于对照组的CAT活性40.4%,与对照组的丙二醛(MDA)水平相比,葡萄糖组、蔗糖组、甜蜜素组和复合碳源组分别显著降低了69.0%、59.7%、38%.0和48.8%。研究表明,水体中添加葡萄糖为碳源能显著提高团头鲂鱼种的生长性能和抗氧化水平,并有效改善水质。     

Effects of different dietary selenium sources (sodium selenite,selenomethionine and nanoselenium) on growth performance,muscle composition,blood enzymes and antioxidant status of common carp (Cyprinus carpio)

This experiment was conducted to compare the effects of different sources of selenium (Se) on growth, muscle Se concentration, muscle proximate composition, blood enzymes and antioxidant status of common carp, Cyprinus carpio. Organic Se (selenomethionine, SeMet), inorganic Se (sodium selenite, Na₂SeO₃), or nanoselenium were each added to the basal diet at 0.7 mg Se kg^?1 diet. Four groups of fish with an average weight of 9.69 ± 0.12 g were fed one of the experimental diets for 8 weeks. Nano‐Se diet resulted in better growth performance (P < 0.05). Fish fed with Se‐supplemented diets showed a higher (P < 0.05) Se content in the muscle and liver tissues. Fish fed nano‐Se had the highest liver glutathione peroxidase, superoxide dismutase and catalase activities (P < 0.05). Liver malondialdehyde level was significantly (P < 0.05) lower in fish fed on SeMet and nano‐Se diets as compared to control. The carp fed on nano‐Se diet had the lowest values of aspartate transaminase and alanine transaminase. Lactate dehydrogenase activity was significantly lower in fish fed on SeMet and nano‐Se diets. This study shows that nano‐Se acts more efficiently on growth performance and antioxidant defence system of common carp than organic and inorganic sources of Se.     

地衣芽孢杆菌对大泷六线鱼生长、肠道消化酶、血清非特异性免疫及抗病力的影响

本研究探讨饲料中添加地衣芽孢杆菌(Bacillus licheniformis)对大泷六线鱼(Hexagrammos otakii)生长、肠道消化酶、血清非特异性免疫及抗病力的影响。选取平均体重为(22.0±2.0) g的大泷六线鱼270尾,随机分成3组(对照组和2个不同菌剂水平的实验组),每组3个平行,每个平行 30尾鱼。对照组投喂仅有蛋白液包裹的基础饲料,实验组投喂含活菌量达5×107 CFU/g(0.5%)和1×108 CFU/g(1.0%)地衣芽孢杆菌的实验饲料。投喂50 d后进行致病菌杀鲑气单胞菌(Aeromonas salraonicida)攻毒感染,测定14 d内累积死亡率。结果显示,实验组饲料中地衣芽孢杆菌可显著提高大泷六线鱼的特定生长率(SGR) (P<0.05)。与对照组比较,0.5%和1.0%地衣芽孢杆菌均可提高大泷六线鱼血清中SOD、CAT及T-AOC活性(P<0.05),降低MDA含量(P<0.05);GSH-Px活性在1.0%实验组较对照组下降,而0.5%实验组较对照组提高。地衣芽孢杆菌实验组鱼血清GS、MDH和HK活性均得到提高(P<0.05),0.5%和1.0%不同剂量组的提高程度不同。地衣芽孢杆菌实验组鱼血清中AST和ALT活性较对照组均降低(P<0.05),CHE和ADA活性较对照组有提高(P<0.05)。实验组鱼肠道胰蛋白酶、淀粉酶和脂肪酶活性均有不同程度的提高,且1.0%实验组活性最强(P<0.05)。攻毒实验结果显示,1.0%地衣芽孢杆菌组大泷六线鱼14 d内累积死亡率仅有35.55% (P<0.05)。由此可见,饲料中添加地衣芽孢杆菌可促进大泷六线鱼生长,提高其肠道消化酶活性及非特异性免疫酶活性,增强其对杀鲑气单胞菌的抵抗能力。     

Gastrointestinal and hepatic enzyme activities in juvenile silvery-black porgy (<Emphasis Type="Italic">Sparidentex hasta</Emphasis>) fed essential amino acid-deficient diets

As amino acids (AAs) are vital molecules in the metabolism of all living organisms and are the building blocks of enzymes, a 6-week feeding trial was conducted for determining the influence of dietary essential amino acid (EAA) deficiencies on pancreatic, plasma, and hepatic enzyme activities in silvery-black porgy (initial weight 4.7?±?0.01 g) juveniles. Eleven isoproteic (ca. 47%) and isoenergetic (ca. 20.5 MJ kg^?1) diets were formulated including a control diet, in which 60% of dietary nitrogen were provided by intact protein (fish meal, gelatin, and wheat meal) and 40% by crystalline AA. The other 10 diets were formulated by 40% reduction in each EAA from the control diet. At the end of the experiment, fish fed with threonine-deficient diet showed the lowest survival rate (P?<?0.05), whereas growth performance decreased in fish fed all EAA-deficient diets, although the reduction in body growth varied depending on the EAA considered. Pancreatic enzymes (trypsin, lipase, α-amylase, and carboxypeptidase A) activities significantly decreased in fish fed the EAA-deficient diets in comparison with fish fed the control diet (P?<?0.05). Fish fed with the arginine-deficient diet had the highest plasma and liver alanine aminotransferase, aspartate aminotransferase, and alkaline phosphatase levels (P?<?0.05). Plasma and liver lactate dehydrogenase and superoxide dismutase showed the highest and lowest values, respectively, in fish fed the arginine and lysine-deficient diets (P?<?0.05). Plasma metabolites were significantly affected by dietary EAA deficiencies (P?<?0.05). The results of this study suggesting dietary EAA deficiencies led to reduction in growth performance as well as pancreatic and liver malfunction. Furthermore, arginine and lysine are the most limited EAA for digestive enzyme activities and liver health in silvery-black porgy.