(革丽)靬金鳟与虹鳟血液生化指标的比较

鱼类血液生化指标是反映鱼体生理状态的重要参数，它在很大程度上反映鱼类的物质代谢强度。同时，血液生化指标检测也是诊断鱼病的重要指标，鱼体一旦产生疾病，其血液生化指标就会发生相应的改变。     

传染性造血器官坏死病毒表面糖蛋白基因核酸疫苗的构建及对虹鳟血液生化指标的影响

为研究传染性造血器官坏死病毒(infectious hematopoietic necrosis virus, IHNV)表面糖蛋白(glycoprotein, G)基因核酸疫苗对虹鳟免疫保护效果及血液生化指标的影响,将IHNV G基因克隆至pMD19-T载体中,连接产物在DH5α中进行转化,获取重组质粒pMD19-TG后回收G基因片段。将鉴定正确的G基因片段利用Bam H I和Xho I酶切位点克隆在真核表达载体pVAX1上,构建核酸疫苗pVAX1-G。重组质粒pVAX1-G按照8μg/尾的剂量注射虹鳟设为pVAX1-G组,同时设8μg/尾空质粒组、PBS对照组和空白组,于免疫后21 d,以100倍半数组织培养感染剂量(tissue culture infective dose, TCID50)通过腹腔注射的方式进行攻毒实验,计算核酸疫苗相对保护率(relative percent survival, RPS),攻毒后收集免疫虹鳟血清进行血液指标检测。结果显示,攻毒后虹鳟血清中16项指标中谷丙转氨酶(ALT)、谷草转氨酶(AST)、碱性磷酸酶(ALP)、总胆红素(TBIL)、总胆汁酸(TBA)、葡萄糖(GLU)、尿素(Urea)、肌酐(CREA)、总蛋白(TP)、白蛋白(ALB)和球蛋白(GLO)与正常虹鳟相比有显著变化,空载组11项指标较pVAX1-G组变化显著;攻毒后14 d pVAX1-G组累积死亡率为19%(19/100),而空载组和PBS对照组分别为62%(62/100)和85%(85/100)。pVAX1-G核酸疫苗对虹鳟免疫保护率为78%。病理学观察发现,免疫pVAX1-G组虹鳟的肝脏、脾脏、肾脏组织未见明显损伤。综上表明,pVAX1-G作为核酸疫苗有助于减轻IHNV对虹鳟的损伤,对IHNV有较好的免疫保护效果。     

光照对章鱼行为习性影响的研究

设置了3个光照强度梯度和红、白、绿、橙、蓝5个光照颜色,研究光照对章鱼行为习性的影响。试验结果表明：光照强度和光照颜色对章鱼的影响都很小;在试验条件下,章鱼的分布比较分散,趋光率不高,所以光照条件不是章鱼养殖的决定性因素。     

棉粕及脱毒棉粕替代鱼粉对虹鳟生长、体成分及血清生化指标的影响

用不同比例棉粕(CM)及FeSO4处理的脱毒棉粕(CM+Fe)替代饲料中0(CM0,对照组)、10%(CM10)、20%(CM20)、30%(CM30)、50%(CM50)、70%(CM70)和50%(CM50+Fe)、70%(CM70+Fe)的鱼粉,配置成8种等氮等能的饲料,喂养(9.79±0.13)g的虹鳟(Oncorhynchus mykiss)10周,每组设3个重复,研究棉粕及脱毒棉粕对虹鳟生长性能、体成分及血清生化指标的影响。结果显示:(1)对照组虹鳟增重率(WG)与CM10～CM50以及CM50+Fe组之间差异不显著,CM70组增重率、蛋白质效率(PER)与其他各组相比显著降低,饲料系数(FCR)显著升高。(2)各试验组虹鳟全鱼和肌肉粗蛋白、粗脂肪、粗灰分与对照组差异不显著;CM0～CM70组肌肉中游离棉酚含量也逐渐增加,CM50+Fe和CM70+Fe组肌肉游离棉酚含量显著低于CM50和CM70组。(3)CM70和CM70+Fe组谷丙转氨酶与谷草转氨酶活性与对照组相比显著升高,CM10～CM50和CM50+Fe组与对照组差异不显著,血清甘油三酯含量逐渐升高,血糖含量与总蛋白含量逐渐降低。结果表明,棉粕替代鱼粉的适宜比例为19.62%。     

中草药添加剂对鲁氏耶尔森菌感染虹鳟血液生化指标的影响

为研究复方中草药对鲁氏耶尔森菌(Yersinia ruckeri)感染虹鳟(Oncorhynchus mykiss)后其血液生化指标的影响,在虹鳟饲料中分别添加两种复方中草药(复方1组、复方2组),持续投喂28 d。在第28天感染鲁氏耶尔森菌,检测感染后72 h的血清生化指标,并统计各组存活率。结果显示:复方中草药组对虹鳟增重无抑制作用。添加复方中草药可提高虹鳟感染鲁氏耶尔森菌后的存活率,其中复方2组的保护效果最好。感染72 h后,复方2组总蛋白、白蛋白、球蛋白、甘油三酯、总胆固醇含量和碱性磷酸酶活性均高于对照组。复方2组谷丙转氨酶、谷草转氨酶活性低于对照组,乳酸脱氢酶活性显著低于对照组。复方1组和复方2组尿酸含量显著低于对照组。复方中草药组总胆红素、尿素氮、肌酐和血糖含量与对照组相比无显著性差异。结果表明,添加复方中草药能提高鲁氏耶尔森菌感染后虹鳟的存活率,其中复方2组的保护效果最好。     

美洲大蠊粉替代鱼粉对虹鳟幼鱼生化指标、抗病力及代谢组学的影响

美洲大蠊(Periplaneta americana)是一种富含蛋白质、脂肪和生物活性成分的昆虫蛋白来源,具有成为鱼粉替代源的潜力。选取初始体质量约3 g的虹鳟(Oncorhynchus mykiss)幼鱼为研究对象,采用美洲大蠊粉分别替代0%、50%鱼粉配制的2种等氮等能饲料,持续投喂18周,探究了美洲大蠊粉替代鱼粉对虹鳟幼鱼生长、生化指标、抗病力及代谢组学的影响。养殖实验结束后,采用嗜水气单胞菌(Aeromonas hydrophila)对剩余虹鳟幼鱼进行攻毒实验。结果表明：实验组幼鱼生长性能及攻毒后成活率均显著高于对照组(P<0.05);实验组幼鱼血清中免疫球蛋白(IgM)、总抗氧化能力(T-AOC)、肝脏中溶菌酶(LZM)和头肾中过氧化氢酶(CAT)活性均显著高于对照组(P<0.05);代谢组学分析结果显示,两组血清中的差异代谢物主要参与甘油磷脂代谢、鞘脂代谢、缬氨酸、亮氨酸和异亮氨酸生物合成等8条生化代谢途径,其中参与甘油磷脂代谢的溶血磷脂酰胆碱(LysoPC)和磷脂酰胆碱(PC)含量均在实验组显著上调。综上,采用美洲大蠊粉替代饲料中50%的鱼粉可显著提高虹鳟幼鱼...     

急性拥挤胁迫对鲤血液中皮质醇及几项生化指标的影响

通过对鲤(Cyprinus carpio)3 h急性拥挤胁迫(密度70g/L)实验,并在胁迫开始前(对照)、胁迫结束后的第0至168 h采样测量几项血液指标。实验结果显示在3 h拥挤胁迫结束之时(0 h),鲤血清皮质醇、血糖和乳酸水平均显著高于胁迫前对照值(P<0.05),而游离脂肪酸水平极显著低于对照值(P<0.01)。之后这些指标继续发生波动,但一段时间后均可恢复至对照水平并保持稳定。实验期间血清甘油三酯和胆固醇水平并未出现显著变化(P>0.05)。该结果提示3 h拥挤胁迫可引起鲤体内血清皮质醇水平及部分血液生化指标发生改变,这可能是为了弥补应激期间机体对能量需求的增大。     

饲料中不同水平磷对西伯利亚幼鲟(Acipenser baeri)血浆生化指标的影响

选择平均体重14.5±1.0g,体长16.0±0.5cm的西伯利亚鲟鱼,随机分成11组,每组3个重复,每个重复15尾.试验以磷酸二氢钙为磷源,配成磷含量分别为0.12%、0.20%、0.29%、0.39%、0.48%、0.60%、0.69%、0.80%、0.99%、1.19%和 1.38%的11组饲料,研究饲料中不同水平磷对西伯利亚幼鲟血浆生化指标的影响.结果表明:血浆总蛋白含量、白蛋白含量和球蛋白含量随饲料磷含量的增加呈逐渐上升趋势,在饲料磷含量0.69%时达最高(18.81g/L、6.99 g/L、11.63 g/L),然后随磷水平升高又逐渐下降;当饲料中磷含量大于0.29%时,磷含最对血浆中总胆固醇和甘油三酯含量_尢显著性影响(P>0.05);由血浆蛋白含量可以得出:西伯利亚鲟最适磷需要量为0.69%.     

饲料蛋白水平对星斑川鲽幼鱼生长、体组成及血浆生化指标的影响

以鱼粉为蛋白源,配制5个不同蛋白质水平(34.85%,40.48%,46.54%,51.54%,56.69%)的等能饲料.以初始体质量为(54.52±0.23)g的星斑川鲽(Platichthys stellatus)为实验对象,在室内循环水养殖系统中进行54 d的摄食生长实验,研究饲料蛋白水平对星斑川鲽幼鱼生长、体组成及血浆生化指标的影响.结果显示:(1)增重率(WGR)和特定生长率(SGR)随着饲料蛋白水平的增加而上升,51.54%和56.69%饲料组之间差异不显著(P>0.05),其余各组差异显著(P<0.05);51.54%饲料组的蛋白质效率(PER)显著高于其他各组(P<0.05);51.54%饲料组的蛋白质沉积率(PRE)也显著高于34.85%、46.54%和56.69%组(P<0.05),但与40.48%饲料组差异不显著(P>0.05).以增重率为参考指标,折线回归分析结果表明,星斑川鲽幼鱼获得最佳增重时对饲料中蛋白质的需要量为53.56%.(2)饲料不同蛋白水平对星斑川鲽幼鱼鱼体灰分含量没有显著影响,但显著影响了鱼体粗蛋白、粗脂肪和水分的含量(P<0.05).51.54%饲料组鱼体粗蛋白含量最高,显著高于34.85%组(P<0.05),而与40.48%、46.54%和56.69%组之间无显著差异(P>0.05);鱼体粗脂肪含量随着饲料蛋白水平的升高而下降,水分含量表现出与粗脂肪含量相反的趋势.(3)饲料蛋白含量对星斑川鲽幼鱼部分血浆生化指标也产生了显著性的影响.血浆总蛋白(TP)以51.54%组最高,与56.69%组差异不显著(P>0.05),,但显著高于34.85%、40.48%和46.54%组(P<0.05);40.48%、51.54%和56.69%组间血浆尿素氮(BUN)含量差异不显著(P>0.05),但显著低于34.85%和46.54%组(P<0.05).综合以上结果,星斑川鲽饲料中蛋白质适宜添加量为51.54%～53.56%.     

饲料中添加β-葡聚糖对虹鳟部分生长指标和血液生理指标的影响

选择初始体重为(454±52)g的虹鳟(Oncorhynchus mykiss),分别投喂添加不同浓度β-葡聚糖(0.05%、0.1%和0.2%)的饲料,饲养30 d后进行取样,分析虹鳟部分生长指标及血液生理指标。结果显示,投喂对应饲料30 d后,0.2%葡聚糖添加组增重率最高,显著高于其他实验组及对照组(P0.05),0.05%葡聚糖添加组增重率最低。0.2%葡聚糖添加组特定生长率显著高于其他组(P0.05),0.05%和0.1%组与对照组无显著差异(P0.05)。0.2%葡聚糖添加组的肝体比显著高于其他实验组及对照组(P0.05)。各添加组的肥满度随着葡聚糖投喂量的增多而升高,其中,最大值出现于0.2%葡聚糖添加组,但各添加组肥满度均显著低于对照组(P0.05)。投喂30 d后,0.05%葡聚糖组白细胞数量显著高于0.2%葡聚糖组及对照组(P0.05),与0.1%葡聚糖组差异不显著(P0.05),0.1%葡聚糖组红细胞数量最高,显著高于其他实验组及对照组(P0.05),葡聚糖组红细胞数量显著高于对照组(P0.05)。0.1%葡聚糖组血红蛋白浓度显著高于其他实验组及对照组(P0.05),对照组鱼的血红蛋白浓度显著低于各实验组(P0.05)。研究表明,在循环水养殖模式下,饲料中添加β-葡聚糖可提高虹鳟的生长性能并改变其部分血液生理指标,本研究中0.2%β-葡聚糖的效果最好。     

LED光色及注射褪黑素对虹鳟抗氧化酶活性及相关激素含量的影响

为探究光色对虹鳟抗氧化酶活性及相关激素含量的影响,对体质量(42.0±1.5)g的虹鳟进行了 28h的持续光照及注射褪黑素处理.实验设置白、红、绿、蓝4种光色,注射和不注射褪黑素两种处理方法,共8个处理组,分别在实验开始后的4、8、12、16、20、24和28h取样,检测血清SOD和头肾CAT的活性以及血清皮质醇和褪黑...     

Effects of light spectrum on growth and physiological status of gilthead seabream Sparus aurata and rainbow trout Oncorhynchus mykiss reared under recirculating system conditions

Previously reported data clearly indicate that depending on species, ambient light spectrum can affect fish growth, physiology, behaviour, reproduction, etc. Since light spectrum can be easily controlled in intensive indoor fish farming facilities, the present study aimed to investigate the effects of coloured light on growth performance (body weight, growth rate, food utilization, carcass composition, etc.) and physiological status (blood and plasma parameters, brain neurotransmitters, tissue fatty acid composition, etc.) of two widely reared fish species, gilthead seabream Sparus aurata and rainbow trout Oncorhynchus mykiss. For this purpose, 240 specimens of S. aurata (29.8 ± 0.13 g) and 60 specimens of O. mykiss (71.4 ± 0.30 g) were exposed to white (full-spectrum, fluorescent lamps), red (605 nm) and blue (480 nm) light (lamps covered with appropriate filters) for 11 weeks under recirculating water systems. Blue light had a significantly negative impact on O. mykiss growth performance accompanied with reduced liver total lipids and plasma glucose and increased brain serotonergic and dopaminergic activity. In the case of S. aurata, red light significantly increased brain dopaminergic activity, while a tendency towards reduced growth was also observed. Since these results indicated the establishment of stressful conditions, O. mykiss and S. aurata should not be reared under blue and red light, respectively. For each species, the effect of the remaining light colours tested, was not clearly differentiated so that an appropriate light spectrum for the most efficient farming of O. mykiss and S. aurata could not be suggested, at least for the time period examined. Nevertheless, present results suggest that light colour should be regarded as a rearing factor worth to be further investigated, especially when recirculating systems are concerned.     

Occurrence of two forms of Y chromosome in rainbow trout (Oncorhynchus mykiss) males from Rutki strain

Morphologically differentiated sex chromosomes are found in only few salmonid species. Some populations of rainbow trout, Oncorhynchus mykiss, exhibit chromosomal polymorphism related to sex. We found sex-related chromosomal polymorphism in fish from the synthetic Rutki strain, Poland, in approximately 85% (n = 22) of examined males (XY-like) whereas the remaining males (n = 4) possessed chromosomes similar to these observed in females (XX-like). To investigate whether males possessing XX-like chromosomes were genotypic males or genotypic females with altered phenotypic sex, androgenetic progeny of four males (representing both XY-like and XX-like forms, n = 2 + 2) was examined. Androgenetic progeny (F₁) of all four fathers consisted of both phenotypic females and males. F₁ male progeny of two fathers showed XX-like chromosomes whereas F₁ male progeny of the other two fathers possessed YY-like (supermale) chromosomes. F₁ were reared further until they were sexually mature. Two males from each of four F₁ families were used to produce F₂ androgenetic and control F₂ generation. All F₂ individuals, androgenetics and control, were phenotypic males at sexual maturation. The results indicate that males possessing XX-like chromosomes are genetic males and they are not sex-reversed females. Thus, the Y chromosome can exist in different morphological forms in farmed rainbow trout. The Y^S chromosome (shorter form, unlike the X chromosome) has a shorter or absent p-arm and lacks the pericentromeric cluster of AT-rich chromatin and the 5S rDNA sequences that are found in the Y^L chromosome (longer form, like the X chromosome).     

黄鳝生长差异基因发掘及其调控机制初步研究

该研究对体质量为 (25.03±0.02) g 的健康黄鳝 (Monopterus albus) 进行了10 周的养殖实验,探究了低鱼粉饲料中添加牛磺酸对黄鳝生长、消化率及肠道酶活性的影响。实验设置了高鱼粉组 (42%, FM)、低鱼粉组 (22%, T₀) 以及在低鱼粉饲料中分别添加0.2% (T_0.2) 和0.5% (T_0.5) 牛磺酸的4个处理组,每组5个重复。结果显示,与FM组相比,T₀组黄鳝的增重率、蛋白质效率、干物质消化率和蛋白质消化率显著下降 (P<0.05),饲料系数显著上升 (P<0.05)。添加适量牛磺酸可显著提高黄鳝的增重率、蛋白质效率和干物质消化率,降低饲料系数 (P<0.05),但T_0.5组黄鳝的增重率、蛋白质效率和饲料系数与T₀组相比无显著性差异 (P>0.05)。此外,T₀组肠道肌酸激酶 (CK)、钠钾ATP酶 (Na⁺-K⁺-ATPase)、碱性磷酸酶 (AKP)、胰蛋白酶 (TRYP) 和脂肪酶活性显著低于FM组 (P<0.05),T_0.2组的上述肠道酶活性均显著升高 (P<0.05),T_0.5组肠道Na⁺-K⁺-ATPase、AKP、TRYP和脂肪酶 (LPS) 活性虽高于T₀组,但无显著性差异 (P>0.05)。综上,低鱼粉饲料中添加0.2%牛磺酸可提高黄鳝的生长,改善肠道消化吸收功能,但添加过量牛磺酸 (0.5%) 效果不明显。     

Effects of emulsified versus saline administration of GnRHa on induction of ovulation in rainbow trout, Oncorhynchus mykiss

The effects of saline-dissolved or Freund's incomplete adjuvant (FIA)-emulsified GnRHa treatment on the induction of ovulation in rainbow trout, Oncorhynchus mykiss, were examined. The FIA-emulsified GnRHa was first diluted in 0.25 ml physiological saline and then mixed with an equal volume of FIA. Fish were selected in the beginning of the spawning season and were allocated into four groups and were treated intraperitoneally with (a) 0.5 ml of emulsified GnRHa (GnRHa–FIA), (b) 0.5 ml saline-dissolved GnRHa in a single injection (GnRHa-1), (c) 0.5 ml saline-dissolved GnRHa in two injections spaced 1 d apart (GnRHa-2) and (d) 0.5 ml of saline (Control). The GnRHa dose in all hormone treatments was 25 µg kg^− 1. All fish in the FIA–GnRHa and GnRHa-2 groups ovulated within 10 and 11 d after treatment, respectively. In contrast, only 75% in the Control fish and 60% of the fish in the GnRHa-1 group ovulated within 36 d after treatment. None of the treatments caused any pre- or post-spawning mortality in the broodstock. Fertilization, eyeing and hatching percentages of the produced progeny were normal in all the treatment groups and did not differ significantly among them. In conclusion, FIA-emulsified GnRHa can be effective in advancing the onset of and synchronizing the ovulation of rainbow trout within a two-week period, thus shortening the egg collection period, without affecting broodstock survival and egg quality.     

QTL for IHNV resistance and growth identified in a rainbow (Oncorhynchus mykiss) × Yellowstone cutthroat (Oncorhynchus clarki bouvieri) trout cross

Infectious hematopoietic necrosis virus (IHNV) is a major constraint to rainbow trout culture. Yellowstone cutthroat trout (Oncorhynchus clarki bouvieri) have greater resistance to this virus than do rainbow trout (O. mykiss), but the genetic mechanism of this resistance is not understood. We conducted a genome scan using a backcross of cutthroat trout into a rainbow trout background to estimate the number and locations of quantitative trait loci (QTL) associated with IHNV resistance and growth in trout. IHNV resistance was considered in terms of both survival (binary trait) and days to death (quantitative trait). The genetic map was scanned using interval mapping via two different approaches: one model considered survival alone and a second two-part model combined both survival and days to death. Three QTL were significantly (P ≤ 0.05) associated with virus resistance genome-wide, explaining 32.5% of the phenotypic variation. Cutthroat alleles at two of these QTL resulted in increased resistance to the pathogen, as expected. No growth QTL were detected in this cross. We suggest that these traits are genetically independent.     

鲑降钙素对虹鳟鳞组织lncRNA表达的影响

为探明鲑降钙素(salmon calcitonin, sCT)对鱼类骨组织钙代谢过程的调节机制, 对虹鳟(Oncorhynchus mykiss) 幼鱼进行 sCT 腹腔注射, 并在注射后 24 h 采集鳞组织进行转录组测序, 分析其中长链非编码 RNA (long non-coding RNA, lncRNA)表达水平的变化。结果显示, 注射 sCT 后的虹鳟鳞组织中共鉴定出 847 个差异表达的 lncRNA, 其中 247 个表达上调, 600 个表达下调。GO 注释结果显示, 差异表达 lncRNA 靶基因主要被注释到转录调控、运输、信号转导、膜、细胞质、金属离子结合和核苷酸结合等功能中。KEGG 通路富集结果显示, 差异表达 lncRNA 靶基因在硫胺素代谢通路、炎症介质对 TRP 通道调节、血小板活化、谷氨酸能突触、神经营养因子通路、ARVC 通路和 NF-kappa B 信号通路等通路中显著富集。利用实时荧光定量 PCR (quantitative real-time PCR, qRT-PCR)对随机选取的 6 个差异表达 lncRNA 的表达量进行验证, 结果显示, qRT-PCR 与 RNA-Seq 结果一致。基于上述结果, 本研究筛选到 MSTRG.68909.2、MSTRG.39805.1、MSTRG.121429.1、MSTRG.9137.1 和 MSTRG.43721.1 共 5 个可能参与虹鳟钙代谢的关键 lncRNA, 这些关键基因的筛选鉴别可为探明硬骨鱼类骨代谢的调控机理提供新的切入点, 为虹鳟养殖生产实践提供参考。     

竹叶抗氧化物浸泡-乳清分离蛋白涂膜对冷藏富硒虹鳟蛋白质理化性质的影响

为从蛋白质水平解释竹叶抗氧化物浸泡-乳清分离蛋白涂膜对富硒虹鳟的保鲜机理,实验将鲜活富硒虹鳟去除头、内脏和表皮,切块后浸泡在1.0%的竹叶抗氧化物（AOB）溶液中（去离子水作为对照）,再进行乳清分离蛋白（WPI）溶液涂膜,25℃下鼓风吹干表面水分后置于4℃冰箱中贮藏1、4、7、10和13 d。测定鱼肉中肌原纤维蛋白和TCA-可溶性肽的含量、蛋白质的分子内价键,以及肌原纤维蛋白的总巯基含量、表面疏水性和二级结构,分析涂膜对冷藏富硒虹鳟蛋白质理化性质的影响。结果显示,冷藏期间,WPI组的肌原纤维蛋白含量和二级结构中β-折叠的含量显著高于对照组。冷藏1～7 d,WPI组的TCA-可溶性肽和二硫键含量以及表面疏水性指数（H₀）显著低于对照组,总巯基含量呈相反趋势,但随着冷藏时间的延长这些差异逐渐减弱。冷藏13 d时,WPI组与对照组无显著差异。3个实验组中,1.0%AOB+WPI组的肌原纤维蛋白、总巯基、氢键、二级结构中α-螺旋和β-折叠的含量在冷藏期间最高,H₀、TCA-可溶性肽、二硫键和二级结构中β-转角含量最低。WPI在鱼块表面形成一层薄膜,可...     

一株虹鳟源传染性胰腺坏死病病毒的分离与鉴定

为明确引起四川石棉某养殖场饲养的虹鳟患病死亡的病原体,实验对自然发病虹鳟进行大体病变观察并对其病原体进行分离,通过人工感染实验及多重RT-PCR鉴定确定病原体WZ160509,并对病原体的主要结构蛋白VP2进行扩增分析,同时对病变组织进行组织病理学观察。结果显示,患病鱼主要临床症状表现为体表发黑,腹部膨大,挤压腹部可见肛门喷射淡黄色黏液便;剖检可见肝脏、肾脏苍白;肠道内无食物,内积黄色黏液。将患病虹鳟组织匀浆液无菌接种虹鳟鱼生殖腺细胞系(rainbow trout gonad cell line,RTG-2)细胞,盲传3代均出现典型的细胞病变。人工感染实验显示死亡率高达90%,并出现与自然患病鱼相同的症状。多重RT-PCR检测发现,自然发病鱼、人工感染鱼以及病变RTG-2细胞均为传染性胰腺坏死病病毒(infectious pancreatic necrosis virus,IPNV)阳性,其主要结构蛋白VP2基因与美国分离株基因组1型聚为一支,且同源性分析表明,WZ160509-VP2与IPNV-VP2(AY026345)的同源性最高,序列一致性为95.8%。组织病理学观察显示,患病鱼胰腺细胞空泡变性,坏死;肝细胞空泡变性,坏死;肾小球轻度炎症,毛细血管通透性增加,肾小囊腔内有红色絮状蛋白类物质渗出,肾小管上皮细胞空泡变性。研究表明,从该养殖场患病虹鳟中分离到的病毒为IPNV。     

Amino acid-chelate: a better source of Zn, Mn and Cu for rainbow trout, Oncorhynchus mykiss

This study aimed to evaluate the amino acid-chelated trace elements as dietary supplement to rainbow trout. Three diets were formulated containing trace elements either from the inorganic salt (SF) or amino acid-chelate (AM). Diets 1 (SF) and 2 (AM) contained the same amount of trace elements from inorganic and amino acid-chelates, respectively. Diet 3 (AM-Hf) was added with trace elements from amino acid-chelatex at one-half of their levels in Diets 1 and 2. Each diet was fed for 15 weeks to three groups of 30 fish each, with an average weight of 1.52±0.21 g. Growth of fish was not affected by the treatment (P>0.05). However, bone (P<0.01) and liver (P<0.05) Cu contents were higher in the AM than the SF group. Similarly, hematocrit level (P<0.05) and alkaline phosphatase (ALP) activity (P<0.01) were higher in the chelate-fed fish. Further, DNA polymerase and CuZnSOD expression in the AM group was highly upregulated (P<0.05) compared to the SF fed fish as quantified by RT-PCR. Absorption and whole body retention of Mn and Zn from the AM were higher (P<0.05) than the inorganic salt. Half supplementation of those fed the elements from AM was at par with the full provision from the inorganic source tested.