不同形式钴对凡纳滨对虾生长和组织钴含量的影响

为研究氨基酸鳌合钴对凡纳滨对虾的营养效果．在凡纳滨对虾配合饲料中添加5、10、15mg／kg的氯化钴和蛋氨酸钴。饲养8周．4周末（饲养中期）称重．8周末称重并采集对虾肝胰脏和肌肉．测定肝胰脏和肌肉中的钴含量。结果表明：钴的添加形式和钴水平不影响对虾0～4周增重率．15mg／kg蛋氨酸钴显著提高了对虾0～8周增重率，且两种形式的钴之间差异显著（P〈0．05）。5、10mg／kg的蛋氨酸钴和5、10、15mg／kg的氯化钴不影响8周末对虾的增重率。特定生长率、饲料系数和蛋白质效率的变化趋势与增重率类似。钴的添加形式和钴水平不影响肌肉中的钴含量。15mg／kg的氯化钴组肝胰脏中钴含量显著高于对照组（P〈0．05）．其他各组间无显著差异；蛋氨酸钴各组肝胰脏中钴含量无显著差异；钴的添加形式不影响肝胰脏中钴含量。统计结果表明。促进生长方面，两种钴之间存在显著差异，蛋氨酸钴的营养效果好于氯化钴。饲料中蛋氨酸钴的添加量为15mg／kg时．对虾生长最快．5mg／kg时．可满足需要。     

抗菌肽对凡纳滨对虾生长和机体免疫的影响

基础饲料(对照组)中添加10g/kg抗菌肽制剂喂养体重0.10±0.01g、体长2.17±0.11cm的凡纳滨对虾(Penaeus vannamei)30d,进行10d的水浴攻毒(鳗弧菌10~8/mL),探讨饲料中添加抗菌肽对凡纳滨虾生长、成活率、免疫保护率,以及肌肉中溶菌酶活性、超氧化物歧化酶活性、总抗氧化能力的影响。结果表明:饲料中添加抗菌肽可显著提高凡纳滨对虾相对增重率、成活率和对致病菌的免疫保护率(P<0.05),但对饲料系数无显著影响(P>0.05);未受外界微生物刺激时,饲料中添加抗菌肽对凡纳滨对虾总抗氧化能力有促进作用(P<0.05),受外界微生物刺激后,饲料中添加抗菌肽喂养凡纳滨对虾可提高对虾超氧化物歧化酶活性(P<0.05)和总抗氧化能力(P<0.01)。因此饲料中添加抗菌肽喂养凡纳滨对虾可提高其机体非特异性免疫。     

溶藻弧菌疫苗对凡纳滨对虾免疫功能的影响

应用溶藻弧菌疫苗饲喂凡纳滨对虾,测定了弧菌疫苗对凡纳滨对虾免疫指标的影响以及 疫苗的免疫保护作用。结果发现,投喂弧菌疫苗后,溶菌活力在12～20d内迅速增强,在20d时 活力达到最高,VF1组高于VF2和VF3组,但VF2和VF3之间差异不显著;凝集效价在投喂后的 第8天开始升高,在14d时达到最高,实验组的凝集活力均高于对照组,但实验组之间无明显的差 异;而超氧化物歧化酶(SOD)活力和溶血活力变化不明显。以每克饲料含疫苗细胞1.0×109、 1.0×108和1.0×107个的浓度投喂,对凡纳滨对虾的免疫保护率分别为66.7%、46.7%和13.3%。 可见弧菌疫苗对凡纳滨对虾的免疫保护率随疫苗浓度的增大而升高。     

珠海地区凡纳滨对虾淡水养殖池浮游植物群落的演替

对珠海凡纳滨对虾淡水养殖池塘浮游植物及其理化因子进行了调查和分析．结果表明：调查中共检出浮游植物143种．优势种主要有林氏藻、螺旋鱼腥藻、小颤藻、微囊藻和点状平裂藻等．物种多样性指数在0．24～2．77之间．优势度与多样性指数呈显著的负相关．相关系数r=-0．984；而均匀度与多样性指数呈显著的正相关．相关系数r=0．967．养殖后期优势度不高。浮游植物的密度及化学因子的浓度到后期都有所上升．藻类密度的剧烈变化会引起氨氮和硫化氢含量的变化；藻类密度的波动滞后于无机氮的波动。群落演替具有突发性、时间短、速度快等特点。     

不同天然饵料对凡纳滨对虾亲虾性腺发育的影响

分别以双齿围沙蚕(Perinereis aibuhitensis)、杜氏枪乌贼(Loligo duvaucelii)、近江牡蛎(Ostrea riuularis)及三者的混合饵料(1∶1∶1)培育凡纳滨对虾(Litopenaeus vannamei)亲虾至性腺发育成熟,通过分析亲虾性腺发育时间、蜕壳间期、交配率、产卵量、变态率,确定培育亲虾的优质饵料。结果表明:投喂双齿围沙蚕或混合饵料的组与投喂杜氏枪乌贼、近江牡蛎组在产卵量、卵巢发育时间、蜕壳间期、交配率、孵化率、变态率方面具有显著差异(P<0.01)。投喂双齿围沙蚕或混合饵料的亲虾平均产卵量可达21.2×104粒/尾,卵巢平均发育时间为101 h,平均蜕壳间期为218 h,平均交配率可达80%,平均孵化率可达62.99%,平均变态率可达82.44%。表明在凡纳滨对虾亲虾培育的过程中,沙蚕单独或与其他天然饵料混合投喂,较乌贼、牡蛎单独投喂对亲虾性腺发育具有更好的促进效果。     

眼柄粗提物对凡纳滨对虾性分化的影响

采用生化方法制备凡纳滨对虾[Litopenaeus(Penaeus)vannamei)]眼柄粗提物,用活体注射法研究不同粗提物剂量对去眼柄凡纳滨对虾卵母细胞直径大小的影响,以检验其性腺抑制素(Gonadinhibiting hormone,GIH)的生物活性;在凡纳滨对虾仔虾后17、22和27 d,分别以不同浓度眼柄粗提物浸泡24 h,结果显示:除0.001个眼柄/mL的GIH浓度外,0.01、0.1和1个眼柄/mL组均显著降低凡纳滨对虾卵母细胞直径(P﹤0.05);浸泡处理后,仔虾后17 d GIH处理组凡纳滨对虾雌性率达70.1%～80.1%;仔虾后22 d GIH处理组雌性率达65.8%～71.7%,各浓度GIH处理组雌性率比对照组(雌雄比例约为1:1)显著提高(P﹤0.05);仔虾后27 d,0.01和1个眼柄/mL处理组雌性率(约58%)略高于对照组,但0.1个眼柄/mL处理组雌性率(73.1%)与对照组相比显著提高(P﹤0.05)。结果表明较低浓度的眼柄粗提物可明显诱导凡纳滨对虾雌性化,在仔虾后22 d前处理效果最佳。     

凡纳滨对虾和斑节对虾对WSSV敏感性的比较

用6.0×104拷贝、1.2×104拷贝和6.0×103拷贝3种剂量白斑综合症病毒(WSSV)对凡纳滨对虾和斑节对虾进行人工注射感染,比较了两种对虾对WSSV敏感性的差异。结果表明,凡纳滨对虾死亡时间随病毒剂量降低而延长,斑节对虾死亡时间没有明显差异;随病毒剂量的降低,凡纳滨对虾人工注射感染后病毒复制高峰时间显著延长,斑节对虾感染后病毒复制高峰时间相同,WSSV在凡纳滨对虾体内比在斑节对虾体内复制慢。对虾携带WSSV数量最低为3.3×107拷贝.g-1,最高为4.3×108拷贝.g-1。凡纳滨对虾比斑节对虾对WSSV的抵抗性更强。     

鱼虾混养池中蓝藻群落结构及其微囊藻毒素含量变化

对广东省中山市三角镇的低盐度鱼虾混养池进行连续采样分析,结果表明,混养池中的蓝藻主要有螺旋藻(Spirulina sp.),鱼腥藻(Anabaena sp.),颤藻(Oscillatoria sp.)、铜绿微囊藻(Microcystis aeruginosa)等,其中盐泽螺旋藻的优势度为0.52~0.73。蓝藻是水体中的优势微藻种群,蓝藻细胞数量占微藻细胞数量的88%~99%,蓝藻细胞数为0.99×10~9~5.89×l0~9 cell/L。混养池微藻多样性指数(H’)为1.16~2.49,养殖水体处于中度污染状态。溶解性无机氮的质量浓度为0.13~2.30 mg/L,正磷酸盐质量浓度为0.25~2.39 mg/L,化学需氧量的质量浓度为1.94~13.79 mg/L。微囊藻毒素(MC-LR)在水中质量浓度为0.18~0.79μg/L。蓝藻细胞数量与化学需氧量之间呈显著的正相关关系,表明蓝藻的生长情况与养殖池中的有机污染程度有密切联系,低盐度的富营养化的水体能促进蓝藻的生长,成为微藻群落中的优势种群。MC-LR的质量浓度与蓝藻细胞数量之间无显著相关。     

Effects of Hypoxia on Dopamine Concentration and the Immune Response of White Shrimp （Litopenaeus vannamei）

Effects of hypoxia on the dopamine concentration and the immune response of White Shrimp Litopenaeus vannamei were studied. The results showed that hypoxia had significant effects on the concentration of dopamine (DA) in the haemolymph, haemocyte count, phenoloxidase activity, phagocytic activity of haemocytes and bacteriolytic and antibacterial activity in the haemolvmph (P<0.05). The concentration of the dopamine in haemolymph reached its maximum in the 3.0 and 1.5mgL-1 DO groups at 12h and 6h, and then returned to normal after 24h and 12h, respectively. All immune parameters decreased with the reduction of dissolved oxygen. Total haemocyte count (THC), the hyaline cells and semi-granular cells in the 3.0mgL-1 DO group became stable after 12h,while granular cells did so after 24h, The THC and different haemocyte count (DHC) in the 1.5mgL-1 DO group became stable alter 24h. Phenoloxidase activity and bacteriolytic activity in the 3.0 and 1.5mgL-1 DO groups reached their stable levels after 24 h and 12 h respectively, while phagocytic activity and antibacterial activity became stable after 24 and 12, and 36 and 24 It, respec-tively. It was also indicated that the changes of dopamine concentrations in haemolymph, haemocyte count and phenoloxidase activ-ity were obviously related to the exposure time under hypoxic conditions.     

大黄对凡纳滨对虾生长和非特异性免疫指标的影响

在凡纳滨对虾饲料中分别添加大黄0、0.5、1.0、5.0、10.0和20.0g/kg,研究大黄对凡纳滨对虾(初始体重为0.34±0.004g)生长及非特异性免疫指标的影响。结果表明,大黄对凡纳滨对虾成活率、增重率、特定生长率、饲料系数、蛋白质效率和蛋白质累积率的影响不显著(P>0.05),对全虾和尾肌肉的灰分、脂肪和粗蛋白含量影响显著,全虾的粗蛋白和粗脂肪含量以1.0g/kg组最高(P<0.05),对凡纳滨对虾血清碱性磷酸酶、酸性磷酸酶、酚氧化酶、超氧化物歧化酶、溶菌酶以及血清总蛋白量等的影响显著,溶菌酶活性以1.0g/kg组最高(P<0.05);细菌感染实验中以1.0g/kg组存活率最高(P<0.05)。以非特异性免疫反应指标及感染实验存活率为指标,凡纳滨对虾饲料中大黄的适宜添加量为1.0g/kg。     

Effects of hypoxia on dopamine concentration and the immune response of White Shrimp (Litopenaeus vannamei)

Effects of hypoxia on the dopamine concentration and the immune response of White Shrimp Litopenaeus vannamei were studied. The results showed that hypoxia had significant effects on the concentration of dopamine (DA) in the haemolymph, haemocyte count, phenoloxidase activity, phagocytic activity of haemocytes and bacteriolytic and antibacterial activity in the haemolymph (P<0.05). The concentration of the dopamine in haemolymph reached its maximum in the 3.0 and 1.5 mg L⁻¹ DO groups at 12 h and 6 h, and then returned to normal after 24 h and 12 h, respectively. All immune parameters decreased with the reduction of dissolved oxygen. Total haemocyte count (THC), the hyaline cells and semi-granular cells in the 3.0 mg L⁻¹ DO group became stable after 12 h, while granular cells did so after 24 h. The THC and different haemocyte count (DHC) in the 1.5 mg L⁻¹ DO group became stable after 24 h. Phenoloxidase activity and bacteriolytic activity in the 3.0 and 1.5 mg L⁻¹ DO groups reached their stable levels after 24 h and 12 h respectively, while phagocytic activity and antibacterial activity became stable after 24 and 12, and 36 and 24 h, respectively. It was also indicated that the changes of dopamine concentrations in haemolymph, haemocyte count and phenoloxidase activity were obviously related to the exposure time under hypoxic conditions.     

Effect of Bioactive Peptides(BPs) on the Development of Pacific White Shrimp(Litopenaeus vannamei Boone, 1931)

The present study was conducted to evaluate the feasibility of replacing fish meal(FM) with bioactive peptides(BPs) in diet of white shrimp(Litopenaeus vannamei). The changes in growth performance, body composition, non-specific immunity, and water quality were examined after the shrimp were fed four diets, in which 0%(control), 33.3%, 66.7% and 100% of FM was replaced by BPs, respectively. The groups were designated as Con, 1/3BPs, 2/3BPs, and 3/3BPs. A total of 720 shrimp with an initial body weight of 1.46 ± 0.78 g were fed the experimental diets for 56 days. The results revealed that: 1) the weight gain rate(WGR) in 1/3BPs, 2/3BPs, and 3/3BPs was significantly higher than that in Con(P 0.05), while no significant difference was found on survival rate and feed conversion ratio(FCR); 2) the whole-body crude protein(CP) and crude lipids(CL) were significantly different among groups, while there was no significant difference between crude ash and phosphorus contents; 3) the levels of acid phosphatase(ACP), lysozyme(LZM), superoxide dismutase(SOD), phenol oxidase(PO) and bactericidal activity increased significantly with the inclusion of BPs; 4) in terms of water quality, no significant difference was found in p H and dissolved oxygen among diets during the whole experimental period. Moreover, even though nitrite and ammonium levels tended to increase with time, there was no significant difference among groups. The results indicated that BPs is an applicable alternative of protein source, which can substitute FM in the diets of L. vannamei; it is able to effectively promote growth performance and improve immunity. Moreover, BPs in the diets had no negative impact on water quality.     

Isolation of Enterococcus faecium with Feeding Attractant Function from Pacific White Shrimp ( Litopenaeus vannamei ) Intestine

In the present study, we isolated the lactic acid bacterium strain SC-01 from Pacific white shrimp(Litopenaeus vannamei) intestine. Using conventional and molecular methods, we identified the bacterium as Enterococcus faecium, and found it had the function of feeding attractant and could inhibit the development of Vibrio parahaemolyticus(zone of inhibition: 14 mm). The attractant effect of its fermentation broth is significantly better than that of the chemical attractant trimethylamine oxide(TMAO)(P 0.05), and is equivalent to that of dimethyl-beta-propiothetin(DMPT) based on the feeding behavior of shrimp. High performance liquid chromatography(HPLC) analysis suggested that inosine-5'-monophosphate(IMP) may be a component of the attractant. A biosecurity evaluation revealed a negative result in hemolytic assays, and no shrimp mortality was resulted from SC-01 fermentation broth challenge. Feeding trials(60 days) indicated that the SC-01 fermentation broth(viable counts: 5.7×10~9 cfu mL~(-1)) could improve feed intake, weight gain rate(WGR) and specific growth rate(SGR), and decrease the count of Vibrio sp. in the intestine of shrimp.     

凡纳滨对虾肠道上皮细胞微胞子虫PCR检测方法的建立与应用

根据Gen Bank中对虾肠道上皮细胞微胞子虫(Enterocytozoon hepatopenaei,EHP)的基因保守序列,设计一对特异性引物,通过优化PCR扩增条件,建立快速检测凡纳滨对虾(Litopenaeus vannamei)EHP的PCR方法。用该方法对EHP阳性虾进行PCR扩增,得到与实验设计相符的330 bp特异性扩增条带,而对白斑综合症病毒(WSSV)、桃拉病毒(TSV)、传染性皮下及造血器官坏死病毒(IHHNV)、对虾杆状病毒(BP)、"棉花虾"微孢子虫、黏孢子虫的阳性虾,以及健康虾的扩增结果为阴性。测序比对发现,PCR产物序列与Gen Bank EHP基因序列的同源性为99.8%,表明该PCR方法检测结果准确。敏感性试验表明,该方法最低可检测出约100 fg的EHP质粒DNA。用该PCR方法检测广东、广西、江苏、山东、海南等地的755份临床样品,共检出阳性样品21份。该PCR方法可用于凡纳滨对虾EHP的快速检测。