卵形鲳鲹仔稚鱼异速生长的研究

以传统的理论生物学研究方法,对孵化后卵形鲳鲹1~36日龄仔、稚鱼各器官测量和分析,研究其在早期环境适应上的异速生长及其生态学含义,以期为卵形鲳鲹的人工繁殖、育苗提供参考。试验结果表明,卵形鲳鲹仔、稚鱼的感觉、呼吸、摄食和游泳等器官快速分化,均存在异速生长现象。在头部器官中,吻长、口宽、眼径和头高在仔鱼期均为正异速生长,稚鱼期头高为等速生长,吻长、眼径和口宽为负异速生长。在身体各部位中,仔鱼期头长、体高和尾长为正异速生长,躯干长为负异速生长;稚鱼期各部分皆为等速生长;在游泳器官中,仔鱼期卵形鲳鲹胸鳍长、尾鳍高和臀鳍长为正异速生长,尾鳍长为等速生长,背鳍长为负异速生长;稚鱼期背鳍长和臀鳍长为正异速生长,胸鳍长、尾鳍长和尾鳍高为等速生长。卵形鲳鲹这些关键部位的快速发育,使外源性营养开始后以最小的代谢损耗获得了生存能力的显著提升,对适应复杂的生存压力具有重要的生态学意义。     

卵形鲳鲹刺激隐核虫病组织病理学研究

利用组织切片、HE染色和显微观察的方法,研究了卵形鲳鲹患刺激隐核虫病组织病理变化。组织切片结果可见,感染鱼的鳃和体表受到直接机械损伤;鱼体在缺氧状态下,入侵的刺激隐核虫有可能对机体产生某种毒素,也可能因刺激隐核虫感染而引发细菌或病毒继发性感染,造成肝、脾和肾脏不同程度的间接性损伤。表现为鳃部机能严重受阻,肝脏脂肪肝变性严重,肝索紊乱,血窦缩小或消失;脾脏组织结构不清晰,有充血、出血和坏死等症状;肾脏结构不清晰,肾小管及肾小体缩小,肾小管细胞融合(黏连),组织间隙松散扩大,局部细胞坏死,存在脂肪粒。     

卵形鲳鳗幼鱼蛋白质需要量的研究

为确定卯形鲳鳆（Trachinotus ovatus）幼鱼的蛋白需求量，进行为期8周的摄食生长试验。以鱼粉和豆粕为蛋白源设计6种试验饲料，蛋白质梯度分别为30．32％、35．56％、41．48％、47．86％、51．70％和54．70％。养殖试验在海水网箱中进行，每种饲料投喂3个网箱（1．5m×1．0m×2．0m），每个网箱放养初始体质量（24．39±0．23）g的卵形鲳鲣30尾。试验结果表明，饲料蛋白水平对卵形鲳够特定生长率（SGR）及饲料效率（FER）有显著影响。随着饲料蛋白水平的升高，试验鱼SGR及FER均显著增加（P〈0．05），而饲料蛋白水平高于41．38％时，各组无显著差异。饲料蛋白水平为47．86％组的卯形鲳够获得最好的SGR和FER。随着饲料蛋白水平升高，卵形鲳鳢鱼体蛋白质量分数也显著增加（P〈0．05）。根据折线模型确定卵形鲳够适宜的蛋白质需要量为45．75％。     

河北省饲料螨初步调查

从沧州、保定、承德三个地区采集的鸡配合饲料、猪配合饲料、豆粕、鱼粉等144个饲料样品中分离得到椭圆食粉螨（Aleuroglyphus ovatus)。调查结果表明，河北省3个地区均已受到不同程度的螨害污染，沧州、保定地区污染较重，承德地区污染较好。而且，潮湿多雨季节和饲料储放不当螨害污染严重。     

麻醉标志方法对3 种鱼类增殖放流存活率的影响

使用增殖放流中常用的挂牌标志法、荧光标志法、剪鳍标志法对卵形鲳鲹、紫红笛鲷和黑鲷3种鱼,在10 mg/L和20 mg/L浓度的丁香酚溶液下分别进行标志.通过在模拟鱼类自然生活环境下观察鱼的行为,统计存活率和脱标情况来确定两个麻醉浓度和3种标志方法对3种鱼的影响.结果表明,10 mg/L丁香酚对鱼苗的影响比20mg/L丁香酚小.对比存活率和标志成功率可知,卵形鲳鲹鱼苗适合在10 mg/L丁香酚下进行荧光标志,紫红笛鲷鱼苗和黑鲷鱼苗适合在10 mg/L丁香酚下进行剪鳍标志.     

卵形鲳鲹的早期胚胎发育

对人工繁殖的卵形鲳鳆（Trachinotus ovatus）受精卵的胚胎发育过程进行了连续观察。受精卵由人工养殖的性成熟亲鱼，经人工催产、自然产卵受精获得。卵形鲳鲮的成熟卵呈圆形，平均卵径为967．8μm。受精卵在水温18～21℃、盐度31的条件下，胚胎发育历时41h27min后孵出仔鱼。胚胎发育为盘状卵裂，胚体后期的发育速度较快；仔鱼脱膜孵化的速度非常快，基本上在1min内就可以完成。初孵仔鱼平均全长为1．548mm，卵黄囊较大。     

Functional identification of ToLAAO genes and polymorphism association analysis of Cryptocaryon irritans resistance in Trachinotus ovatus

‘Marine white spot disease’ is caused by Cryptocaryon irritans infection and can lead to high mortality in Trachinotus ovatus. L-Amino acid oxides (LAAOs) play a key role in antibacterial activity and parasitic activity. To investigate the function of the LAAO (ToLAAO) and LAAO-like (ToLAAO-like) genes of T. ovatus, this study explored the sequence characteristics and relationship between polymorphisms and traits of anti-C. irritans. The ToLAAO and ToLAAO-like ORF sequences obtained from the whole genome of T. ovatus were 1563 and 1584 bp, which encoded 520 and 527 amino acids respectively. Both sequences contained a highly conserved flavin adenine dinucleotide-binding domain and a similar amino oxidase domain. Sequence multiple alignment analysis showed that ToLAAO and ToLAAO-like had the highest homology to the LAAO sequence of Larimichthys crocea. Quantitative real-time polymerase chain reaction (qRT-PCR) results showed that ToLAAO and ToLAAO-like mRNA were generally expressed in 10 tissues. ToLAAO mRNA was highly expressed in the testis, while ToLAAO-like mRNA was highly expressed in muscle tissue. After C. irritans infection, ToLAAO and ToLAAO-like mRNA were significantly upregulated in the skin and spleen, while only ToLAAO mRNA was significantly upregulated in the liver and head kidney, and only ToLAAO-like mRNA was significantly upregulated in the gills. Five SNP sites were identified from the ToLAAO and ToLAAO-like genomic sequence fragments, and two sites (6200C/T and 6237G/A) of LAAO were significantly associated with resistance to C. irritans. These results suggest that ToLAAO and ToLAAO-like genes play crucial roles in defending against the immune response to C. irritans.     

Development and characterization of five novel cell lines from snubnose pompano,Trachinotus blochii (Lacepede, 1801), and their application in gene expression and virological studies

Five novel permanent cell lines have been established from gill, heart, kidney, eye and fin of snubnose pompano, Trachinotus blochii. They were designated as snubnose pompano gill (SPG), snubnose pompano heart (SPH), snubnose pompano kidney (SPK), snubnose pompano eye (SPE) and snubnose pompano fin (SPF), respectively. All these cell lines were characterized and cryopreserved successfully at different passage levels. Cell lines were passaged every alternate day; SPG, SPH, SPK, SPE and SPF cell lines attained passage levels of 68, 74, 82, 79 and 106, respectively, since the initiation of their development in 2019. The cell lines grew well in Leibovitz's 15 medium containing 15% foetal bovine serum at 28°C. Immunophenotyping of the cell lines revealed the presence of fibronectin and pancytokeratin. No mycoplasma contamination was found. The transfection study revealed the gene expression efficiency of these cell lines by expressing the green fluorescent protein (GFP). The authentication on origin of cell lines from T. blochii was confirmed by amplification of species-specific mitochondrial cytochrome oxidase I gene. The results showed the susceptibility of these cell lines to fish nodavirus (FNV) and tilapia lake virus (TiLV) and resistance to cyprinid herpesvirus 2 (CyHV-2). The FNV infection in the cell lines was confirmed by RT-PCR, Western blot, ELISA and immunocytochemistry, while TiLV infection was confirmed by RT-PCR assay. These results revealed that these cell lines are suitable for virological and foreign gene expression studies.     

不同糖源饲料对卵形鲳鲹(Trachinotus ovatus)生长、体组成、血糖水平和肝脏糖酵解酶活力的影响

分别以葡萄糖、蔗糖、糊精、玉米淀粉和糊化玉米淀粉为糖源配制成5种等氮等脂饲料,对初始体重为(31.24±0.58) g 的卵形鲳鲹(Trachinotus ovatus)进行为期56 d 的饲养实验,比较不同糖源饲料对卵形鲳鲹生长、体组成、血液指标和糖酵解酶活力的影响,筛选出最有利于生长的糖种类。结果显示,不同糖源对卵形鲳鲹增重率(WG)和特定生长率(SGR)均有显著影响(P<0.05),且随糖分子量增大有增大的趋势,其中,糊化玉米淀粉的 WG 和 SGR 最高分别为335.35%和2.62%/d;不同糖源组的脏体比(VSI)、肝体比(HSI)、肝糖原和肌糖原含量以及血糖、血浆总胆固醇和甘油三酯也有显著性差异(P<0.05),且均为葡萄糖组最高;除己糖激酶(HK)活力外,各糖源组的其他糖酵解酶活力均有显著性差异(P<0.05),亦是葡萄糖组最高。在本实验条件下,卵形鲳鲹对淀粉类大分子糖的利用效果优于葡萄糖等小分子糖类,糊化玉米淀粉组的生长效果最好;不同糖源饲料对卵形鲳鲹糖代谢过程中糖原合成、糖脂转化、糖酵解等途径的相关指标有一定影响。     

Effects of soybean meal replacement with fermented soybean meal on growth,serum biochemistry and morphological condition of liver and distal intestine of Florida pompano Trachinotus carolinus

This study evaluated the suitability of commercially produced fermented soybean meal (FSBM) known as PepSoyGen?, in a plant‐based diet for Florida pompano, Trachinotus carolinus fingerlings. An 8‐week growth trial was conducted to evaluate the effect of four isonitrogenous and isolipidic diets containing 0, 206, 309 and 410 g/kg FSBM, replacing approximately 0%, 50%, 75% and 100% SBM (designated as Basal, FSBM 50, FSBM 75 and FSBM 100, respectively) on growth performance, body composition, serum biochemistry and morphological condition of liver and distal intestine of Florida pompano. There were no significant differences in final mean weight, percentage weight gain, thermal unit growth coefficient and feed conversion ratio in all treatments. For serum biochemistry analysis, there were no significant differences in total protein, albumin, glucose, cholesterol, bile acids, plasma alkaline phosphatase, alanine aminotransferase and aspartate aminotransferase activities in all treatments. Cellular infiltration, presence of goblet cells and the width of lamina propria in the distal intestine were partly improved in fish fed FSBM 75 and 100 compared to the fish fed FSBM 50 and basal diet. Glycogen granulation, inflammation and nuclear change condition in the liver of pompano were better as the inclusion of fermented product increased. Results of this study indicate that FSBM can be utilized as an alternative protein source and microbial fermentation process could improve the functional properties of SBM.