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。     

Effect of dopamine injection on the hemocyte count and prophenoloxidase system of the white shrimp Litopenaeus vannamei

Effects of dopamine injection on the hemocyte count, phenoloxidase activity, serine proteinase activity, proteinase in-hibitor activity and α2-macroglobulin-like activity in L. vannamei were studied. Results showed that dopamine injection resulted in a significant effect on the parameters measured (P < 0.05), while no significant difference was observed in the control group (0.85% NaCl). In the experimental groups,the hemocyte count reached the minimum in 3 h;granular and semi-granular cells became stable after 12 h and hyaline cells and the total hemocyte count became stable after 18 h. Phenoloxidase activity reached the minimum in 6 h, and then became stable after 9 h. Serine protease activity and proteinase inhibitor activity reached the minimum in 3 h, and α2-macro-globulin-like activity reached the maximum in 3 h,and all the three parameters became stable after 12 h. The results suggest that the activating mechanisms of the proPO system triggered by dopamine are different from those triggered by invasive agents or sponta-neously activated under a normal physical condition.     

On the ultrastructure and classification of the hemocytes of penaeid shrimp,Penaeus vannamei (Crustacea, Decapoda)

The ultrastructure of hemocytes ofPenaeus vannamei was examined by transmission electron microscope. Three types of hemocytes were identified: hyaline cell, small-granule cell and large-granule cell. Hyaline cells are the smallest of the hemocytes, lack electron-dense granules, have average size of 11.11 μm (SE±0.50,n=10)×6.96μm (SE±0.55,n=10), comprise 25.8% (SE±2.87,n=4×10) of the hemocytes; small granule cells are the most abundant type of hemocytes, comprise 58.1% (SE±3.40,n=4×10) of the hemocytes, contain small electron—dense granules, have average size of 10.78 μm (SE±0.60,n=10)×8.63 μm (SE±0.44,n=10); and large-granule cells comprise 16.1% (SE±2.55,n=4×10) of the hemocytes, are filled with large electron dense granules, have average size of 12.51 μm (SE±0.63,n=10)×8.99μm (SE±0.71,n=10). This research was supported by the National Climbing Project B, PDB6-6-3. Contribution No. 3448 from the Institute of Oceanology, Chinese Academy of Sciences.     

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.     

Modulation by Biogenic Amines for the Hemocyte Count and Prophenoloxidase Exocytosis via Receptors in Litopenaeus vannamei

Hemocyte counts and phenoloxidase(PO)activity were examined after hemolymph being incubated in dopamine(DA),noradrenaline(NE)and serotonin(5-HT).Results showed that all the three biogenic amines(BAs)had a significant impact on total hemocyte count(THC),differential hemocyte count(DHC),and intracelluar and extracelluar phenoloxidase(PO)activity.Among these Bas,DA had the strongest effect on the above parameters,whereas 5-HT had the least effect.Preincubation with D1 receptor antagonist SCH23390,D2 receptor a...     

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。     

蜕壳素对凡纳滨对虾生长及表观消化率的影响

研究了外源性蜕皮激素对凡纳滨对虾生长和表观消化率的影响 ,实验时在基础饲料中分别添加 0 .1%、0 .2 %、0 .4 %的两种市售蜕壳素产品 ,制成 6种外源性脱壳素配合饲料 ,不添加的基础饲料作为对照组 ,试验在 2 6 0L玻璃钢循环水养殖系统中 ,每个剂量组设 3个重复 ,8周生长试验结果表明 :市售蜕壳素产品能有效地促进对虾生长 ,试验结束时 ,试验组虾体增重分别较对照组增加 16 .8%、7.5 2 %、5 .9%、11.4 %、2 9.0 7%、16 .5 3% ,但是凡纳滨对虾对饲料粗蛋白的表观消化率没有明显地提高 ,凡纳滨对虾对脂肪的表观消化率较低。推算凡纳滨对虾饲料中最佳蜕皮酮添加量为 6 0mg/kg。     

Effects of different enzymatic hydrolysis methods on the bioactivity of peptidoglycan in Litopenaeus vannamei

The effects of different hydrolysis methods on peptidoglycan(PG) were assessed in terms of their impact on the innate immunity and disease resistance of Pacific white shrimp,Litopenaeus vannamei.PG derived from Bifidobacterium thermophilum was prepared in the laboratory and processed with lysozyme and protease under varying conditions to produce several different PG preparations.A standard shrimp feed was mixed with 0.05% PG preparations to produce a number of experimental diets for shrimp.The composition,concentration,and molecular weight ranges of the soluble PG were analyzed.Serum phenoloxidase and acid phosphatase activity in the shrimp were determined on Days 6-31 of the experiment.The protective activity of the PG preparations was evaluated by exposing shrimp to white spot syndrome virus(WSSV).Data on the composition of the PG preparations indicated that preparations hydrolyzed with lysozyme for 72 h had more low-molecular-weight PG than those treated for 24 h,and hydrolysis by protease enhanced efficiency of hydrolysis compared to lysozyme.SDS-PAGE showed changes in the molecular weight of the soluble PG produced by the different hydrolysis methods.Measurements of serum phenoloxidase and acid phosphatase activity levels in the shrimp indicated that the PG preparations processed with enzymes were superior to the preparation which had not undergone hydrolysis in enhancing the activity of the two serum enzymes.In addition,the preparation containing more low-molecular-weight PG enhanced the resistance of the shrimp to WSSV,whereas no increased resistance was observed for preparations containing less low-molecular-weight PG.These findings suggest that the immunity-enhancing activity of PG is related to its molecular weight and that increasing the quantity of low-molecular-weight PG can fortify the effect of immunity enhancement.     

基于模糊数学评价法优化凡纳滨对虾真空微波干燥工艺

【目的】探求真空微波干燥凡纳滨对虾的最佳工艺条件,以期为开发凡纳滨对虾即食食品提供技术参考。【方法】以新鲜凡纳滨对虾为原料,模糊数学感官评分为主要考察指标,在单因素试验基础上,选择载装量A、功率B、真空度C为自变量,利用响应面法和模糊数学评价法对真空微波干燥工艺进行优化。【结果】以感官评定为基础对真空微波干燥凡纳滨对虾的品质进行权重分析,得到权重集K=(色泽0.335,滋味0.305,香气0.215,组织质地0.145)。建立二次多项回归方程:Y=84.588+1.084A+1.409B+1.700C-7.353A²-8.793B²-13.860C²,显示载装量A、功率B、真空度C对感官评分有极显著影响(P<0.01)。通过响应面分析,得到真空微波干燥凡纳滨对虾的最佳工艺条件:载装量75 g,加热功率400 W,真空度0.08 MPa。在此条件下,真空微波干燥凡纳滨对虾品质良好,感官评分为(85.6±0.07)分,与预测值85.92分误差较小。【结论】响应面法优化凡纳滨对虾真空微波干燥工艺具有操作简单、优化条件精确、结果显示直观等优点;建立的回归方程能反映装载量等三个因素对指标的影响规律,并可进行实际预测。     

微囊藻毒素对凡纳滨对虾免疫相关酶活力的影响

通过毒性注射实验,探究微囊藻毒素(MC-LR)对凡纳滨对虾(Litopenaeus Vannamei)肝脏免疫相关酶活力的影响。结果表明,注射MC-LR后,凡纳滨对虾肝胰脏组织的超氧化歧化酶、谷胱甘肽过氧化酶、过氧化物酶、酸性磷酸酶、碱性磷酸酶和溶菌酶的酶活力呈先增大后减小的变化趋势。超氧化歧化酶、谷胱甘肽过氧化酶和过氧化物酶活力在对虾注射MC-LR 4 h后达到峰值,比对照组分别增加了15.62%、18.76%和32.86%,随后酶活力逐渐减小;而酸性磷酸酶和碱性磷酸酶酶活力在对虾注射MC-LR 2 h后即显著增加,比对照组分别增加了25.02%和37.99%,随后酶活力逐渐减小;溶菌酶在对虾注射MC-LR后8 h达到最大值,比对照组增加了33.57%,随后酶活力逐渐减小。MC-LR能显著影响凡纳滨对虾的免疫相关酶活力(P0.05),引起凡纳滨对虾的应激反应和抑制它们的免疫相关酶活力。     

微酸性电解水结合复合保鲜剂对凡纳滨对虾冷藏期间蛋白特性影响

【目的】研究微酸性电解水(SAEW)结合迷迭香提取物(RE)-柠檬酸(CA)复合保鲜剂处理对凡纳滨对虾(Litopenaeus vannamei)冷藏期间蛋白特性变化影响,探讨此法用于虾类贮藏保鲜的效果。【方法】将样品分别经SAEW、质量分数4%RE+质量分数1%CA(RC)、SAEW结合RC(SAEW+RC)和无菌水(CK)处理10 min后,自然沥干15 min,装入PE保鲜袋于(4±1)℃冰箱中保藏,每2 d测定样品的pH值、总挥发性盐基氮(TVB-N)、总巯基含量、Ca²⁺-ATPase活性、化学键、肌原纤维小片化指数(MFI)与内源荧光强度(IFI)等指标,并结合聚丙烯酰胺凝胶电泳(SDS-PAGE)进行综合分析。【结果】复合处理能延缓凡纳滨对虾贮藏期间pH与TVB-N值的升高,抑制总巯基含量下降,CK、RC、SAEW与SAEW+RC组样品的Ca²⁺-ATPase活力分别由初始0.16、0.17、0.17与0.17μmol/(mg·min)降至0.12、0.13、0.12与0.14μmol/(mg·min),MFI值较初始值上升1.88、1.73、1.76和1.54倍,可见SAEW+RC对延缓Ca²⁺-ATPase活性下降与MFI值的上升有较好作用。同时,SAEW+RC处理还能减缓蛋白质分解、氧化和变性,保持蛋白质化学键与IFI值的相对稳定。【结论】微酸性电解水结合复合保鲜剂处理能较好抑制凡纳滨对虾冷藏期间的蛋白质氧化分解,延缓其品质劣变。     

Effects of dietary vitamin C on the immune function of shrimps, Penaeus chinensis

Prepared in this experiment were six groups of diets, i.e. VC0, VC1, VC2, VC3, VC4 and VC5 with the contents of vitamin C (VCmg(100 g)⁻¹ diet) of 0, 100, 200, 400, 800, and 1200 respectively. It was found that vitamin C increased the concentrations of immunoglobulin-like (IgG-like, IgA-like and IgM-like) substances in the serum of Penaeus chinensis after a feeding period of 3 weeks. The differences among groups were significant (P<0.01), but there was no difference in the contents of complement3-like and complement4-like substances in the serum (P>0.05). Phenoloxidase (PO) activity in the serum of VC3 group shrimps was higher than that of VC0 and other groups, but no significant difference was observed between VC0 group and other groups. Furthermore, bactericidal activity of the serum to Vibrio parahaemolyticus in shrimps fed with the VC1 diet was higher than that in the other groups (P<0.01), while no difference was demonstrated among all groups for the bactericidal activity to Vibrio alginolyticus (P>0.05). It is, therefore, suggested that vitamin C (100–400 mg(100 g)⁻¹ diets) could be used as an immunostimulant of P. chinensis.     

The effect of three culture methods on intensive culture system of pacific white shrimp (Litopenaeus vannamei)

Different culture methods may affect the intensive culture system of Pacific white shrimp(Litopenaeus vannamei) regarding water quality and growth and economic performance.This study evaluated the potential effects of three culture methods through cultivation of juvenile shrimps under consistent tank management conditions for 84 d.The three methods involved shrimp cultivation in different tanks,i.e.,outdoor tanks with cement bottom(mode-C),greenhouse tanks with cement bottom(mode-G) and outdoor tanks with mud-substrate(mode-M).Results showed that water temperature was significantly higher in mode-G than that in mode-C(P < 0.05).In contrast to the other two treatments,mode-M had stable pH after 50 d cultivation of shrimps.In the mid-late period,the average concentrations of TAN,NO2-N,DIP and COD were significantly lower in mode-M and mode-G compared with those in mode-C(P < 0.05).Despite lack of differences in the final shrimp weight among different treatments(P > 0.05),mode-M had significantly higher shrimp yield,survival rate and feed conversion rate(P < 0.05) than other modes.There were significant differences in revenue and net return among different treatments(P < 0.05).These demonstrated that the treatments of mode-G and mode-M were conductive to the intensive culture system of L.vannamei.     

Effect of Replacing Fish Meal with Extruded Soybean Meal on Growth,Feed Utilization and Apparent Nutrient Digestibility of Juvenile White Shrimp (Litopenaeus vannamei)

Extruded soybean meal(ESBM) was evaluated as a protein source for partial replacement of fish meal(FM) in diets of juvenile Litopenaeus vannamei. In the control diet(Diet 1), FM protein was replaced with increasing dietary levels of ESBM(4.28%, 8.40%, 12.62%, 16.82%, and 25.26%) at 10%, 20%, 30%, 40%, and 60% levels(Diets 2 to 6, respectively). An eight-week feeding trial was conducted on 720 juvenile shrimp(0.67 g ± 0.01 g mean initial weight), and nutrient digestibility of the six diets was determined. ESBM could replace 20% of FM without causing a significant reduction in growth of shrimp, but other dietary treatments strongly affected whole body composition. Crude protein content of the whole body fed Diet 6 was significantly lower than that fed Diet 2(P 0.05), while crude lipid content of the whole body fed Diet 5 or 6 was significantly higher than that fed Diet 2(P 0.05). Protein digestibilities of Diets 5 and 6 were significantly lower than that of Diet 1(P 0.05). Digestibility of lipids ranged from 96.97% in Diet 6 to 98.34% in Diet 3, whereas dry matter digestibility decreased with increasing replacement level. This study indicates that 20% FM replacement with ESBM in the basic diet containing 40% protein and 30% FM is optimal for juvenile L. vannamei.