Effect of polysaccharides extracts of algae Ulva rigida on growth,antioxidant, immune response and resistance of shrimp,Litopenaeus vannamei against Photobacterium damselae

This study was carried out to investigate the effect of water‐soluble polysaccharides extract of algae Ulva rigida (WPU) as dietary supplement on growth performance, antioxidant enzyme activity, lysozyme and phenoloxidase activity, and resistance of shrimp (Litopenaeus vannamei) subjected to bacterial infection with Photobacterium damselae. Three replicate groups of shrimp (1.0 g) were fed four diets containing four levels, 0 or control, 0.5, 1 and 1.5 g/kg of WPU for 8 weeks over the growth trial. Thereafter, 30 shrimps from each dietary treatment were infected with bacteria P. damselae to evaluate disease resistance of infected shrimp. The results of this study showed that WPU was effective as a growth promoter for L. vannamei. The best growth rate was observed in shrimp fed 1.5 g/kg of WPU diet. Regarding antioxidant defences, the diets supplemented with three levels of WPU stimulated glutathione peroxidase and catalase activates in experimental shrimps. MDA content of L. vannamei‐fed diet containing WPU 1.5 and WPU 1.0 was lower than WPU 0 and WPU 0. 5 diets. Also, lysozyme and phenoloxidase activities of shrimp receiving WPU at 1.0 and 1.5 level were significantly higher than those fed WPU 0 and WPU 0.5 diets. In addition, using WPU extract in all diets decreased mortality in L. vannamei in a dose‐dependent manner after challenge with P. damselae. These results suggest that incorporation of water‐soluble polysaccharides from green algae U. rigida at 1.5 g/kg doses improves growth and antioxidant activity and enhances the immune responses in shrimp L. vannamei.     

中国沿海石莼属绿藻的ITS和5S rRNA序列分析

对采自2008年、2009年中国沿海的石莼属(Ulva)海藻进行了ITS基因间隔区序列和5S rRNA序列系统发育分析,探讨了绿潮藻的分类问题。根据ITS序列分析结果,绿潮藻中存在着几个不同的种,包括LPP复合体(Ulva linza-procera-prolifera)中的种类以及Ulva compressa。绿藻的5S rRNA序列系统分析结果的差异性较明显,但也在一定程度上印证了上述结论。根据本文中ITS基因间隔区及5S rRNA序列分析结果,本实验采集到的绿潮藻的后代中至少存在U.prolifera、U.linza和U.compressa三个种类。据此推断,我国黄海海域2008年、2009年爆发的绿潮中,存在上述三个种类。     

A Growth Assessment of Juvenile Abalone Haliotis laevigata Fed Enriched Macroalgae Ulva rigida

The experiment was conducted to assess the growth of juvenile greenlip abalone Haliotis laevigata fed a range of Ulva rigida diets with different nitrogen contents and an artificial pelleted diet. The minimal nutrient concentration resulting in significant enrichment of U. rigida was 2.25 mg N l^?1. The maximum nitrogen content obtained by U. rigida in this study was 6.099%, which resulted from an inorganic nutrient concentration of 7 mg N l^?1. However, no further significant increase in enrichment occurred from nutrient concentrations of 10 and 15 mg N l^?1. Abalone specific growth rate in shell length (SGR_L) and wet weight (SGR_W) and foot muscle yield were significantly higher for abalone fed the artificial diet compared to those fed any U. rigida diet. Abalone fed U. rigida enriched in less than 15 mg N l^?1 had similar growth rates compared to abalone fed unenriched U. rigida. Abalone fed the artificial diet contributed a higher percentage of weight gain into the valuable foot muscle. The foot muscle moisture content of abalone fed the artificial diet was significantly lower than that of abalone fed any U. rigida diet. The conclusions reached by this study should assist Australian abalone producers in assessing the potential benefits of using U. rigida as an effluent biofilter and subsequent food source for the commercially important juvenile greenlip abalone.     

Influence of nitrogen availability on the biochemical composition of three unicellular marine algae of commercial importance

Chaetoceros calcitrans (Paulsen) Takano, Tetraselmis suecica (Kylin) Butch. and Isochrysis galbana Parke were grown in artificial seawater containing either normal (9·8 mg atoms litre^?1) or reduced (0·613 mg atoms litre^?1) nitrogen. When grown in the nitrogen-deficient medium protein decreased and carbohydrate increased in all three species; lipid, however, increased in Chaetoceros and Isochrysis but decreased in Tetraselmis.The biochemical composition of Tetraselmis and Isochrysis sampled during the post-exponential phase of growth from normal medium was similar to that of cells growing exponentially in nitrogen-deficient medium. Salinities of 10–35‰ did not affect protein levels in Tetraselmis or Isochrysis but carbohydrate increased and lipid decreased in Isochrysis over the salinity range. Temperatures of 18–25 °C had little effect on the cell composition of either species.The energy potentially available from a unit volume of Chaetoceros and Isochrysis cells from normal medium was similar to that from cells grown in nitrogen-deficient conditions in both species. Tetraselmis had 34% more energy available when grown in normal compared to nitrogen-deficient medium.     

Effect of green and clear water and lipid source on survival, growth and biochemical composition of Pacific white shrimp Litopenaeus vannamei

Despite the shrimp ability to obtain additional nutrients from food organisms endogenously produced within the ‘green water’ system has been suggested as one of the causes for the better performance of Pacific white shrimp reared in ‘green water’ in comparison with ‘clear water’, the nutritional components responsible for these effects have yet to be determined. The present study aims to understand the importance of natural food organisms in zero‐water exchange systems as source of essential fatty acids for the Pacific white shrimp Litopenaeus vannamei. Five treatments were tested: two conducted in mesocosms systems with shrimp‐fed diets containing either fish oil (FO) or olive oil, and another three conducted in clear water with shrimp‐fed diets containing either olive oil, a docosahexaenoic acid (DHA)‐rich oil or an arachidonic acid (ARA)‐rich oil. The presence of higher levels of fatty acids 16:1n‐7, 17:1, 20:4n‐6, 20:3n‐3 and 22:5n‐6, characteristic of floc lipids, in shrimp reared in mesocosms denoted their assimilation from the floc. Substitution of FO by olive oil in diets for shrimp reared in mesocosms did not affect growth or survival. Survival and growth of shrimp reared in mesocosms was better than those reared in clear water and fed an olive oil diet, whereas DHA or ARA enrichment of non‐fish oil (NFO) diet improved survival of shrimp reared in clear water. Higher survival rate, triglyceride and DHA content in whole body and eyes of shrimp fed a DHA‐rich diet suggests that under these conditions, in clear water, it is necessary to include at least 4.8 g kg^?1 DHA in diet dry weight. ARA enrichment seemed to negatively affect growth. The nutritional contribution of the floc to shrimp in mesocosm culture reduces or eliminates the need for a dietary source of FO and illustrates the importance of DHA and ARA to enhance shrimp survival in clear water conditions.     

Growth and biochemical composition of juvenile green abalone Haliotis fulgens fed rehydrated macroalgae

Under controlled laboratory conditions, juvenile green abalone Haliotis fulgens were fed rehydrated natural feeds to determine the effects on growth, survival, feed efficiency and biochemical composition of the digestive gland and muscle. Five macroalgae, Ulva sp. (Chlorophyta), Eisenia arborea, Macrocystis pyrifera, Egregia menziesii (Phaeophyta) and Porphyra perforata (Rhodophyta) were tested. The macroalgae promoted growth, although, depending on the species, there were considerable differences in growth, feed efficiency and biochemical composition of the digestive gland and muscle. Mean growth rate in length and weight and survival rate varied within the ranges 1.6–15.1 μm day^?1, 1.4–8.1 mg day^?1 and 44–69%, respectively. Significantly, higher growth rates were obtained from Egregia menziesii, M. pyrifera and P. perforata. Feed conversion ratio ranged from 6.5 to 42.4 for P. perforata and Ulva sp. Protein, carbohydrates and lipid contents in the digestive gland ranged from 113 to 180, 98.3 to 448 and 17.2 to 23.3 mg g^?1_, respectively. In muscle, the ranges were 66.9–123, 9.5–23.2 and 2.8–3.9 mg g^?1, respectively. This study shows that rehydrated Egregia menziesii, M. pyrifera and, particularly, P. perforata are more efficient in promoting growth than Ulva sp. and E. arborea which match results reported by other authors when using the same fresh macroalgae.     

营养盐对海萝生长和藻体生化成分的影响

研究了不同营养盐添加量对海萝( Gloiopeltis furcata) 盘状体萌发、生长、成活以及藻体生长和生化成分的影响。海萝盘状体和海萝藻体分别培养于添加不同质量浓度的营养盐[ 硝酸钠( NaNO3) 0 mgL-1 、10 mgL-1、40 mgL-1、80 mgL-1、10 mgL-1、40 mgL-1、80 mgL-1和相对应磷酸氢二钾( K2HPO4 ) 0 mgL-1、0 mgL-1、0 mgL-1、0 mgL-1、1 mgL-1、4 mgL-1 、8 mgL-1 ] 的天然海水中。结果表明, 添加营养盐的各组盘状体萌发出直立体的百分率和成活率没有比空白对照组的高; 添加营养盐的各组藻体质量与空白对照组没有显著性差异, 但添加NaNO3 质量浓度为40 ～80 mgL-1组的叶绿素a 和藻红蛋白含量则明显高于空白对照组( P0. 05) 。研究结果显示, 海萝盘状体阶段可不添加营养盐进行培养; 藻体阶段可添加NaNO310～40 mgL-1和K2HPO44 mgL-1进行培养。     

The effect of nitrate supplementation on the biochemical composition of benthic diatoms and the growth and survival of post-larval abalone

Elevating the nitrogen concentration in microalgal growth media can elevate the protein content of the algae and consequently increase their dietary value to molluscs. This study examined the protein content, and dietary value to abalone post-larvae, of seven benthic diatoms acclimated to high-(“H” = 49.4 mg NO₃-N l^− 1) and standard-nitrate (“S” = 16.5 mg NO₃-N l^− 1) Walne medium. In Experiment 1, the level of nitrate in the culture medium did not significantly affect the protein content of Cocconeis sp., Cylindrotheca closterium or Nitzschia ovalis, and variation in the growth of post-larval Haliotis iris was not associated with nitrate level or the protein content of the diatoms. When the same six diatom diets were added daily as cell suspensions, growth and survival were much lower than for the equivalent strains fed as established films (P < 0.0001). In Experiment 2a, the protein content of Navicula incerta was elevated by nitrate supplementation, and the high nitrate strain retained a higher protein content (P = 0.005) even after 24 days growing in unenriched, flowing seawater. Haliotis rufescens post-larvae grew significantly faster when fed N. incerta H than when fed N. incerta S (P = 0.006) and survival was also higher with this diet (67 versus 54%). In Experiment 2b, there was no significant effect of nitrate level on protein content of four diatoms or the performance of post-larval H. rufescens. There was, however, a strong positive correlation (r = 0.95, P < 0.0001) between post-larval survival and the lipid content of the diatom diets. Post-larval growth showed positive, but marginally non-significant, relationships with diatom protein and carbohydrate, but no relationship with lipid content. Overall, only one of seven benthic diatom species acclimated to high-nitrate growth medium displayed significantly elevated protein content. Diatom protein content explained relatively little of the variation in food value of diatom strains for post-larval abalone but lipid content correlated strongly with post-larval survival.     

盐度对星斑川鲽幼鱼肌肉生化组成及能量收支的影响

在水温18℃情况下,测定了星斑川鲽(Platichthys stellatus)幼鱼(10.60±0.27 g)在盐度为0、8、16、24、32时的生化组成和能量收支。结果表明8.0盐度组的星斑川鲽幼鱼的粗蛋白和粗脂肪均高于其他盐度组,水分含量低于其他盐度组,而鱼体能值则是盐度0组最高,各组间差异不显著(P>0.05)。另外盐度对摄食能和排泄能有显著影响(P<0.05)。     

Growth,tissue metabolites and digestive functionality in Sparus aurata juveniles fed different levels of macroalgae,Gracilaria cornea and Ulva rigida

The aim of this study was to evaluate the inclusion of two macroalgae as dietary ingredients on growth, body composition, intermediate metabolism, intestinal enzymes and gut histology of Sparus aurata juveniles. Six isocaloric and isonitrogenous diets incorporating 5%, 15% or 25% of Gracilaria cornea or Ulva rigida meal were tested against a control diet. Duplicate groups of fifteen fish (14 g) were fed the experimental diets for 70 days. Growth performance showed an inverse linear relationship with the inclusion level of Gracilaria. Feed conversion ratio increased significantly in fish fed 25% Gracilaria. Ulva presented a quadratic relationship with the lowest SGR at 15% of inclusion. Fish fed 25% Ulva exhibited significantly lower lipid content than those fed control diet. Overall, metabolites did not show differences with specimens fed control diet, except for plasmatic glucose and muscle lactate. Intestinal proteolytic activity was reduced with the macroalgae inclusion level, but all fish showed the same enzyme pattern. The histological study revealed no negative effect on liver and intestine structure by the macroalgae inclusion. The present work demonstrated that these ingredients can be used in practical diets for sea bream, but a more comprehensive research is needed to determine the optimum dietary level in a longer feeding trial.     

羊栖菜的生长和生化组成的影响因素

综述了羊栖菜生长和生化组成的多种影响因素,包括非生物因素(温度、光照强度、营养盐、重金属)和生物因素(种质、生长阶段、敌害生物),以期为羊栖菜资源的保护和可持续利用以及提高羊栖菜的产量和品质提供理论依据。     

漂浮绿潮藻浒苔孢子/配子的繁殖过程

以引起绿潮灾害的漂浮优势种浒苔(Ulva prolifera)为材料,对其繁殖过程和特性进行研究。结果发现漂浮浒苔多以配子体形式出现。每平方厘米单层藻体叶片可以产生2.84×10P6P~6.62×10P6P个孢子或1.14×10P7P~2.65×10P7P个配子,放散的生殖细胞中91.6%~96.4%可以成功萌发形成新的藻体,在绿潮暴发高峰期,平均1 g浒苔藻体30%的叶片所形成的生殖细胞囊完全放散生殖细胞后,可以产生0.84×10P8P~8.21×10P8 P株新藻体。漂浮浒苔强大的繁殖力是生物量快速扩增的重要原因,也是中国沿海绿潮暴发的一个主要原因。     

生物操纵对常见底栖丝状绿藻的控制研究

为探究安全高效调控丝状绿藻生长的解决方法,本研究开展了两次生物操纵实验。首先研究了耳萝卜螺（Radix auricularia）、子陵吻鰕虎鱼子陵吻虾虎鱼（Rhinogobius giurinus）、中华鳑鲏（Rhodeus sinensis）和日本沼虾（Macrobrachium nipponense）对底栖丝状绿藻—水绵（Spirogyra sp.）的控制效果,结果表明,中华鳑鲏处理组的固着态水绵生物量从实验前期的90g/m2下降到实验末期的34 g/m2,相对于其它生物操纵对象,中华鳑鲏对浮游态和固着态水绵抑制效果尤为显著。进而,我们深入探讨了中华鳑鲏对多种底栖丝状绿藻,包括水绵、水网藻（Hydrodictyon reticulatum）、刚毛藻（Cladophora sp.）生长的抑制效果。结果表明,鳑鲏处理组中,固着态水绵生物量（146 mg/m2）显著低于对照组（8423mg/m2）,固着态水网藻生物量（49mg/m2）略低于对照组（56mg/m2）,固着态刚毛藻生物量（486mg/m2）也低于对照组（1516mg/m2）,结果进一步表明支持中华鳑鲏对水绵、水网藻、刚毛藻均存在一定的抑制效果,其中对水绵抑制效果具有显著性。中华鳑鲏在抑制底栖丝状绿藻生长的同时对水体中浮游植物和浮游动物造成的影响并不显著,表明作为控制丝状绿藻的潜在生物操纵对象具有很好的应用前景。     

光照强度对海黍子生长及部分生化指标的影响

在20、40、80、120、200μmol/m2·s光照强度下,研究了光照梯度对海黍子Sargassum muticum的生长及藻体部分生化指标的影响。结果表明,在80～200μmol/m2·s光照范围内时,海黍子的特定生长率都比较高,且无显著差异,光照低于80μmol/m2·s后,生长率下降,显示了海黍子适宜较高光强的特性。叶绿素a、可溶性蛋白、可溶性糖在光照20μmol/m2·s下含量最高。褐藻多酚含量在光照200μmol/m2时比其余光照条件下增加明显。此特性对于从海黍子中提取褐藻多酚天然产物具有一定的指导意义。     

2010年绿潮藻营养成分分析及其食用安全性评价

近几年来,中国南黄海海域连续暴发的绿潮灾害引起了广泛关注,为综合利用绿潮藻,实验采用国标规定方法,对2010年采自江苏和山东的绿藻类海藻的基本营养成分、叶绿素、氨基酸、矿质元素及其重金属含量进行了测定与分析.结果显示,碳水化合物占绿潮藻组成成分的35.82％～52.43％;粗蛋白含量随采集时间的不同变化较大,为31.04％～12.11％;粗脂肪含量很低,不足藻体的1％;叶绿素含量差异较大,随采集时间的延后其含量显著下降;氨基酸含量较高,其中必需氨基酸占总氨基酸的含量可达37.45％,呈味氨基酸天门冬氨酸、谷氨酸、甘氨酸和丙氨酸含量较高;矿质元素含量丰富,其中Ca、Fe、Zn等含量都较高,重金属元素Pb、Hg、Cd等含量均低于国家标准中的限量要求.固着绿藻的成分变化不明显.     

饥饿和补偿生长对史氏鲟幼鱼摄食、生长和体成分的影响

报道了饥饿和再投喂对史氏鲟幼鱼摄食、生长以及生化组成的影响.22±2℃条件下,随着饥饿时间延长,幼鱼白肌的RNA/DNA比值不断减小,体重逐渐下降,后者与同期对照组之间存在极显著性差异(P<0.01).饥饿7d,鱼的肝糖原和肌糖原含量显著降低(P<0.05),但随着饥饿时间的延长,肝糖原和肌糖原含量则出现不同程度的回升;脂肪含量和蛋白质含量分别在饥饿14d和21d时下降幅度最大,提示史氏鲟幼鱼动用储存物质的顺序依次是糖原、脂肪和蛋白质.而饥饿过程中鱼体水分和灰分含量则有所上升.恢复投食后,饥饿幼鱼的摄食强度增大,生长加快,其中7d、14d饥饿组幼鱼的RNA/DNA比值达到或接近正常投喂组水平,但21d饥饿组的比值仍明显低于正常投喂组(P<0.05).恢复投食30d后,7d和14d饥饿组幼鱼体重接近对照组(P>0.05),21d饥饿组的终体重未能赶上对照组(P<0.05),这表明史氏鲟幼鱼的补偿生长随饥饿时间不同而异.试验结束时,各处理组鱼体生化组成与正常投喂组没有显著差异(P>0.05).     

不同投饲率对日本黄姑鱼幼鱼生长及鱼体生化成分的影响

采用一种饲料5个投喂水平(鱼体重1.0%、2.0%、3.0%、4.0%、5.0%)在水温26~28℃的条件下对日本黄姑鱼幼鱼(26.85±1.69g)进行了40d生长实验。结果表明:特定生长率和相对增重率随着投饲率的增加呈先上升后平稳的趋势,饲料利用率随着投饲率的升高呈先下降后平稳再下降的趋势;鱼体的水分含量随投饲率的增加而下降,蛋白质和脂肪含量随投饲率的增加而升高,投饲率对灰分无影响。根据最大相对增重率和最大饲料利用率,确定日本黄姑鱼幼鱼适宜投饲率在水温26~28℃时为3.0%。     

Effect of algal diet and temperature on the biochemical composition of the rotifer, Brachionus plicatilis

Rotifers were fed on four species of unicellular algae (Dunaliella tertiolecta, Pavlova lutheri, Phaeodactylum tricornutum and Isochrysis galbana) at a range of temperatures. Measurements were made of growth rate, weight and level of total protein, carbohydrate and lipid. Large differences were found in rotifer weight and biochemical composition as a result of feeding and starvation. There were only minor differences attributable to the type of alga used as a food.     

饥饿对真鲷生长及生化组成的影响

在２０℃条件下,对真鲷进行了不同时间的饥饿处理后再投饵的恢复生长实验。饥饿１５ｄ的真鲷体重下降７．０５％,鱼体水分含量略有上升,蛋白质含量的比能值略有下降,脂肪含量和灰分含量没有明显改变。这表明真鲷在饥饿过程中主要消耗蛋白质作为身体的能量来源。分别给饥饿处理０（对照）、３、６、９、１２和１５ｄ的真鲷投饵,在饱足摄食的条件下生长２周。各饥饿处理组的鱼体生化组成及比能值均接近,并恢复到对照组水平。饥饿３、６ｄ处理组在恢复生长的特殊生长率、摄食率明显高于对照组,而食物转化率与对照组无显著差异;饥饿９、１２和１５ｄ处理组的特殊生长率和食物转化率均显著高于对照组,而摄食率与对照组无显著差异。结果表明真鲷幼鱼具有超补偿生长能力,短期饥饿的真鲷在恢复生长中通过显著提高摄食水平来达到补偿生长;而继续延长饥饿时间则通过显著提高食