南澳贝藻混养互利机制的初步研究

以牡蛎和龙须菜为试验材料,进行了两个阶段不同投放比例的室内模拟混养试验,试验周期均为4周,各试验组分别为:对照组、龙须菜单养组、牡蛎单养组、牡蛎龙须菜低密度混养组、牡蛎龙须菜中密度混养组和牡蛎龙须菜高密度混养组,其中除对照组和龙须菜单养组外,各试验组牡蛎密度均为27只/m3,第一阶段龙须菜密度分别为:0,47,0,47,94,188g/m3,第二阶段龙须菜密度为:0,158,0,158,316,854g/m3。定期采样测定水体中营养盐(NO2-N,NO3-N,NH4-N,PO4-P)的含量及养殖生物的生长情况。试验结果表明,第一阶段试验结束时,投放牡蛎的试验组与未投放牡蛎的试验组水体氮、磷含量差异显著(P0.05)。第二阶段试验结束时,投放牡蛎的各试验组磷酸盐和硝酸盐含量差异显著(P0.05),高密度混养组的磷酸盐含量和硝酸盐含量与牡蛎单养组相比分别降低了43%、30%,说明龙须菜明显吸收了水体中的氮、磷,混养系统氮、磷利用更为合理,其中龙须菜854g/m3,牡蛎27只/m3的高密度混养组投放密度最为合理。     

不同温度和盐度条件对脆江蓠生长及其生化组分的影响

在不同温度（14℃、17℃、20℃、23℃和26℃）和不同盐度（5、10、15、20、25、30和35）条件下培养脆江蓠（Gracilaria chouae）,观察测定其生长及藻体生化组分的变化。试验结果显示,脆江蓠生长的适宜温度为14～26℃,最适温度为17～20℃,在此温度条件下藻体可以保持最快相对生长速率（relative growth rate,RGR）;温度高于20℃时脆江蓠的生长受到抑制。在生长状态、光合色素和抗氧化等方面,脆江蓠对低温的耐受能力要比高温强。脆江蓠生长的适宜盐度为20～35,最适盐度为30,在此盐度条件下藻体可以保持最快RGR,盐度低于20时脆江蓠的生长受到抑制。高盐度培养条件下脆江蓠在生长状态、光合色素和抗氧化等方面强于低盐度培养条件。     

龙须菜对异育银鲫消化吸收、免疫及抗氧化性能的影响

本试验旨在评估龙须菜替代饲料中的菜粕对异育银鲫幼鱼消化吸收、免疫及抗氧化性能的影响,确定龙须菜的适宜替代范围。选取健康且规格一致的异育银鲫幼鱼450尾,随机分为6组,每组3个重复,每个重复25尾,以不含龙须菜的基础饲料为对照组饲料,以3%（D1）、6%（D2）、9%（D3）、12%（D4）、15%（D5）龙须菜替代菜粕配制成的饲料为试验饲料饲喂试验鱼8周,所有饲料等蛋等脂,试验结束时测定各组异育银鲫消化吸收、免疫及抗氧化相关酶活性。结果显示,与对照组相比,投喂龙须菜饲料各组异育银鲫肝脏消化酶活性无显著差异（P<0.05）;D1组异育银鲫前肠碱性磷酸酶、肝脏超氧化物歧化酶活性,D1和D2组异育银鲫前肠γ-谷氨酰转肽酶活性显著升高（P<0.05）,D5组异育银鲫前肠脂肪酶、碱性磷酸酶活性和肝脏超氧化物歧化酶活性显著下降（P<0.05）;D1~D3组异育银鲫肾脏酸性磷酸酶活性、D2~D5组异育银鲫血清溶菌酶活性及D2、D3组异育银鲫血清总胆固醇含量和前肠总抗氧化能力显著升高（P<0.05）,而D5组异育银鲫血清总蛋白含量显著下降（P<0.05）。综上所述,饲料中添加3%~6%的龙须菜可在一定程度上提高异育银鲫消化吸收与免疫性能,当龙须菜替代水平达15%时,会对鱼体消化吸收和健康产生负面影响。     

Cultivation of Gracilaria (Rhodophyta) in shrimp pond effluents in Brazil

Shrimp aquaculture produces a large amount of waste, including nitrogen and phosphorus. To investigate the utilization of those elements as sources of nutrients for the growth of the red seaweed, Gracilaria sp. J. Agardh, an experiment in shrimp pond effluents was carried out over a period of 5 months. The biomass varied significantly (P < 0.01), reaching a maximum of 2540 g m^?2 and a minimum of 380 g m^?2. The mean was 1418 ± 708 g m^?2. The higher biomass values occurred during the first 15 days and sometimes exceeded the initial inoculum by 190%. According to the results, production of 23.93 t ha^?1 year^?1 (dry weight) can be expected. anova showed significant differences in RGR (relative growth rate) values (P < 0.05). RGR varied from 8.8% per day to 1.8% per day. The fluctuation of nutrients was mainly influenced by pond fertilization frequency, with NH₄ being the most abundant nutrient. Correlations between RGR and environmental parameters during the study period were not significant (P > 0.05). We conclude that Gracilaria sp. can be cultivated in shrimp ponds effluents. However, despite this relative success, it is necessary to perform some adjustments regarding the utilized cultivation technique.     

Polyculture of milkfish Chanos chanos (Forsskal) and the red seaweed Gracilariopsis bailinae (Zhang et Xia) in brackish water earthen ponds

Growth, net production, and survival rates of milkfish cultured with Gracilariopsis bailinae at two stocking density combinations (T₁– 30 fingerlings 100‐m^?2 pond+1‐kg G. bailinae 4‐m^?2 net cage, T₂– 30 fingerlings 100‐m^?2 pond+2‐kg G. bailinae 4‐m^?2 net cage) in brackish water earthen ponds over four culture periods were determined. The control (T₃) was stocked at 30 fingerlings 100‐m^?2 pond. Specific growth and production rates of G. bailinae were also calculated. There were no significant differences in mean growth, survival, and net production rates of milkfish between the three treatments. Irrespective of stocking singly or in combination with G. bailinae, significantly higher mean growth and mean production rates for milkfish were obtained during the third culture period of year 1 than those obtained from the other culture periods. Survival rates were not significantly different among the four culture periods. There were no significant differences in mean specific growth and mean net production rates between the two stocking densities of G. bailinae. Significantly higher mean specific growth and mean net production rates of red seaweed were also obtained during the third culture period of year 1 than those obtained from other culture periods. The production of milkfish and red seaweed was higher during the dry season. Growth rates of milkfish was positively correlated with temperature and salinity, while net production rates were positively correlated with temperature and total rainfall, but was inversely correlated with dissolved oxygen. G. bailinae growth and net production rates were positively correlated with water temperature and salinity. Results show that milkfish can be polycultured with G. bailinae grown in net cages in brackish water ponds at stocking density combination of 30 fingerlings 100‐m^?2 pond+1‐kg G. bailinae 4‐m^?2 net cage.     

Evaluation of three seaweeds Gracilaria bursa-pastoris, Ulva rigida and Gracilaria cornea as dietary ingredients in European sea bass (Dicentrarchus labrax) juveniles

The aim of this study was to evaluate the inclusion of three seaweeds Gracilaria bursa-pastoris (GP), Ulva rigida (UR) and Gracilaria cornea (GC) as dietary ingredients on the performance, nutrient utilisation and body composition of European sea bass juveniles. Six experimental diets were formulated to replace 5% (GP-5, UR-5, and GC-5 Diets) and 10% (GP-10, UR-10 and GC-10 Diets) fish protein hydrolysate (CPSP) by each of the three seaweeds. A control diet was used, without inclusion of any seaweed. Diets were fed to duplicate groups of 25 European sea bass (Dicentrarchus labrax) juveniles (IBW = 4.7 g) for 10 weeks. Growth performance was only significantly reduced (P < 0.05) in fish fed the GC-10 diet, whereas the feed conversion ratio increased significantly in those fish. The apparent digestibility coefficients of dry matter and lipid were significantly lower in fish fed diet GC-10 relative to those fed the control diet. Carcass composition was similar among treatments, although fish fed GC-10 exhibited significantly higher ash content.The results obtained in this study suggest that the inclusion of G. bursa-pastoris (GP) and U. rigida (UR), up to 10%, can be considered as very interesting ingredients in diets for sea bass juveniles, as no negative consequences on growth performance, nutrient utilization or body composition were observed. On the other hand, the inclusion of G. cornea (GC) should be limited to 5% of the diet.     

不同温度及二氧化碳浓度下培养的龙须菜光合生理特性对阳光紫外辐射的响应

为了研究不同温度及CO₂浓度下培养的大型海藻对紫外辐射的生理学响应,选取龙须菜(Gracilaria lemaneiformis)作为实验材料。实验设置两个温度梯度(20 ℃和24 ℃),两种CO₂浓度(390 μL/L和1000 μL/L)以及3种辐射处理,即可见光(PAR)处理(滤除紫外线A(UV-A)、紫外线B(UV-B),400-700 nm)、可见光加紫外线A(PA)处理(滤除UV-B,320-700 nm)、PAB处理(全波长辐射280-700 nm)。结果表明,酸化、升温以及紫外辐射处理都未影响大型经济红藻龙须菜的叶绿素a和类胡萝卜素的含量。然而紫外辐射处理显著降低了龙须菜的有效光化学效率,其抑制水平在酸化处理的藻体中更为显著,并且随着温度的上升而进一步加剧;酸化与温度耦合使藻体对紫外辐射的敏感性增加,导致其较低的修复速率以及较高的损伤速率。     

芋根江蓠和异枝江蓠早期腐解过程及其氮磷释放规律的研究

对芋根江蓠(Gracilaria blodgettii)和异枝江蓠(Gracilaria bailinae)进行了为期12 d的腐解过程比较研究。结果表明:(1)实验结束时,芋根江蓠、异枝江蓠腐解的时间分别为10 d、8 d,藻体失重率分别为22.52%、8.50%,2种江蓠均处于腐解早期阶段,腐解过程分先快后慢两个阶段,芋根江蓠腐解速率大于异枝江蓠。在腐解过程中芋根江蓠藻体丙二醛(MDA)含量大于异枝江蓠,但超氧化物歧化酶(SOD)活性小于异枝江蓠,说明芋根江蓠膜系统受损程度较大,对逆境胁迫的抗氧化能力较弱。(2)腐解过程中,营养盐释放规律为:TNTP,氮磷释放不同步,磷释放滞后;其中TN释放量为:芋根江蓠异枝江蓠;TP释放量为:芋根江蓠异枝江蓠。腐解水体中TN、TP含量为:芋根江蓠异枝江蓠。(3)芋根江蓠藻体含水率、C/N初始值高于异枝江蓠,前者分别为95%、52.11,后者为91%、24.01。综上所述,芋根江蓠腐解的时间较长,藻体失重率和分解速率较大,抗氧化能力较弱,TN释放量较多,所以芋根江蓠腐解的程度比异枝江蓠大;2种江蓠氮磷含量、抗氧化能力、藻体含水率和C/N不同可能是导致藻体腐解、氮磷释放差异的原因。     

水杨酸对龙须菜抗高温生理的影响

以龙须菜为材料,研究了不同浓度水杨酸对高温下龙须菜的生长速率、抗氧化酶、渗透调节物质、藻胆蛋白、叶绿素荧光特性和HSP70基因的影响。结果表明,水杨酸处理组不论是生长、酶活性和膜脂受损情况都不同程度优于对照组,其中5.0、10.0μg/mL处理组效果较好。10.0μg/mL水杨酸处理组效果最为明显,日生长速率与对照组相比增长了340%。在处理第3天,10.0μg/mL处理组各指标达到最大,SOD增长了74%,POD增长了70%,CAT增长了40%。脯氨酸和甘露醇分别增长了70%和26%。藻红蛋白增加了46.2%,藻蓝蛋白增长了40%。与对照组相比,MDA含量第1天下降最为显著,下降了10%。高温胁迫下,龙须菜叶绿素荧光参数Fv/Fm、Fv/Fo、qP和ΦPSⅡ均明显降低,非光化学淬灭(NPQ)呈现先上升后下降的趋势。水杨酸处理能有效减缓5种龙须菜叶绿素荧光参数的降低程度。水杨酸处理后HSP70基因表达量较对照组低。本实验结果表明水杨酸具有增强龙须菜抗高温胁迫的作用。     

江蓠及其共附微生物活性物质的研究进展

江蓠属于大型红藻,含有多种活性物质,具有营养保健功能。对江蓠及其共附微生物的活性物质研究进展进行了概述,旨在为开发利用江蓠资源提供理论基础。