Increased gonad growth of the purple sea urchin (Strongylocentrotus purpuratus) fed the giant kelp (Macrocystis pyrifera) and the sea lettuce (Ulva lactuca) enriched with nutrients

Adult (Strongylocentrotus purpuratus) purple sea urchins were fed giant kelp (Macrocystis pyrifera) and sea lettuce (Ulva lactuca) macroalgae that were unenriched and enriched with nutrients. Urchins were fed over 10 weeks (5% body weight per day) under laboratory conditions to determine the effect of macroalgae species and treatment (enriched and unenriched) on growth, gonad index and gonad quality. Significant differences were observed when urchins were fed enriched Macrocystis pyrifera (MPE). Gonad weight increased from 0.7 ± 0.1 g (mean ± SD) to 5.9 ± 1 g, and gonad index increase from 3.5 ± 1.5% to 14.9 ± 2.3% over 10 weeks. Significant differences were also noted in gonad quality, and gonad colour and firmness were better in urchins that were fed unenriched M. pyrifera (MPUE) and MPE – whereas texture did not differ between M. pyrifera treatments and unenriched U. lactuca (ULUE). With regard to taste, gonads were sweeter in MPE‐fed individuals. Enriched U. lactuca (ULE) failed to grow gonads significantly; as a result, their quality was unacceptable for the market. These results suggest that S. purpuratus experience increased gonad production and quality in short periods when fed nutrient‐enriched M. pyrifera.     

Preliminary Studies on Cryopreservation of Vegetative Thalli of Some Economically Important Seaweeds of India

The effects of cryoprotectants and their concentrations, prefreezing temperature, equilibration time, thawing temperature, and the regenerative efficacy of cryopreserved vegetative thalli (apical tips) of Gracilaria corticata J. Agardh., Ulva lobata Duetzing, and Hypnea musiformis (Wulfar) Lamouroux were evaluated. The apical tips were suspended in various cryoprotective solutions and slowly cooled to ?40?C over a period of 4 h. After the slow cooling step, the suspensions were immediately immersed in liquid nitrogen (LN), which were thawed after 2 days. Both U. lobata and H. musiformis survived maximally in 10% DMSO, whereas 10% glycerol was found most suitable for G. corticata. A slow cooling temperature of ?40?C and thawing temperature of 40?C were found most suitable irrespective of the species. The equilibration time of 60 min was found most suitable for G. corticata, while 45 min was sufficient for both H. musiformi and U. lobata. Cryopreserved vegetative thalli were then successfully regenerated, though the survival was considerably reduced up to a period of 28 days after which it was stabilized.     

浒苔对赤潮异湾藻的克生作用

研究了浒苔对赤潮微藻—— 赤潮异湾藻生长的克生效应。结果表明, 浒苔新鲜组织对赤潮异湾藻的生长具有强烈的克生效应; 一次性添加浒苔培养过滤液对赤潮异湾藻生长没有显著的抑制作用, 而半连续添加浒苔培养过滤液对赤潮异湾藻生长具有显著的克生作用; 浒苔干粉末和甲醇抽提液均对赤潮异湾藻的生长产生显著的抑制作用。试验结果表明, 抑制赤潮异湾藻生长的物质很可能更多地存在于浒苔组织内, 向环境中分泌的克生物质较少。因而, 克生物质的连续分泌是有效克制赤潮异湾藻生长的关键。同时, 克生作用存在着明显的浓度效应, 当抑制物浓度达到一定阈值才表现出明显的克生作用, 在阈值之上浓度越高克生作用越强。     

Dietary branched‐chain amino acid supplementation affects growth and hepatic insulin‐like growth factor gene expression in yellowtail,Seriola quinqueradiata

We investigated the effect of dietary supplementation with a branched‐chain amino acid (BCAA) mixture (valine, leucine and isoleucine) on juvenile yellowtail (Seriola quinqueradiata) growth and hepatic insulin‐like growth factor (IGF) gene expression. Total dietary BCAA content was 8.1, 8.5, 9.0 and 9.8 g   kg^?1 for the control, 0.4%, 1.0% and 2.0% BCAA experimental groups, respectively. Body weight was measured on day 77, after which fish were fasted for 3 days and refed; the livers were then removed 3 or 9 h later for analysis of hepatic gene expression. Body weight significantly increased in the BCAA‐supplemented groups. Hepatic expression of IGF1 and IGF2 significantly increased in the 2% BCAA group at 3 and 9 h after refeeding. In the 1% BCAA group, hepatic IGF1 expression tended to be higher at 9 h than in the control group after refeeding. Also, hepatic IGF2 significantly increased at only 9 h after refeeding in the 1% BCAA group. In conclusion, dietary supplementation with crystalline BCAAs increased growth and hepatic expression of IGF1 and IGF2. These results suggest that dietary crystalline BCAA supplementation would be a valuable addition to yellowtail aquaculture practices.     

低盐胁迫下模拟酸雨对裂片石莼光合作用生理特性的影响

为探讨低盐胁迫下模拟酸雨对裂片石莼光合作用、抗氧化活性等生理特性的影响,实验设置3个盐度梯度、2个p H水平,运用叶绿素荧光仪、液相氧电极等仪器测定叶绿素荧光参数和光合放氧速率,采用氮蓝四唑法、考马斯亮蓝G250法及蒽酮硫酸比色法测定超氧化物歧化酶(SOD)活性、可溶性蛋白和糖含量。结果发现:(1)模拟酸雨(pH 4.4)处理显著抑制了裂片石莼的生长,且受盐度的影响。p H 8.1、盐度10处理的裂片石莼具有较高的生长速率;盐度越高,模拟酸雨的影响越大。(2)模拟酸雨(pH 4.4)处理显著抑制了裂片石莼的最大光合效率(F_v/F_m)和有效光化学效率(F_v′/F_m′),但受盐度的影响不显著;模拟酸雨和低盐度协同降低了裂片石莼的最大相对电子传递速率(rETRmax)。(3)模拟酸雨(pH 4.4)降低了裂片石莼的暗呼吸和光合放氧速率,但受盐度的影响不显著。(4)正常盐度及正常p H处理的裂片石莼SOD活性最高;在盐度(10、25)处理下,模拟酸雨抑制了裂片石莼的SOD活性;而在盐度5处理时,模拟酸雨提高了SOD活性。(5)相对于海水正常p H处理,模拟酸雨显著降低了裂片石莼可溶性蛋白含量,但其可溶性糖含量显著提高,尤其是在低盐条件下。研究表明,模拟酸雨对裂片石莼生长的影响受海水盐度的调控,这在一定程度上也将影响近岸海域大型海藻的生态群落组成。     

孔石莼质体蓝素氨基酸序列分析和分子进化

以孔石莼(Ulva pertusa)质体蓝素氨基酸序列在NCBI以BLASTp进行同源性检索,将获得具有一定同源性的不同生物的质体蓝素氨基酸序列进行生物信息学分析。共比较37种生物的38个氨基酸序列,包括13种藻类,1种苔藓,23种陆生被子植物的24个氨基酸序列。发现孔石莼质体蓝素的氨基酸序列与其它序列的同源性从26．4％～88．8％不等,所有生物的质体蓝素氨基酸序列表现出较大的保守性和进化性;基于不同生物质体蓝素成熟肽的氨基酸序列之间的同源性,构建了它们的系统进化树,这些系统进化树能够较准确地表现各种生物系统进化关系,可以说生物的质体蓝素的氨基酸序列可作为生物系统进化的一个分子依据。     

Dietary requirements for leucine,isoleucine and valine (branched‐chain amino acids) by juvenile red drum Sciaenops ocellatus

The objective of this study was to determine the minimum dietary requirements of the branched‐chain amino acids (BCAAs: leucine [Leu], isoleucine [Ile] and valine [Val]) for juvenile red drum, Sciaenops ocellatus. This was accomplished by conducting three independent 49‐day feeding trials with juvenile red drum. Experimental diets were prepared by supplementing a basal diet containing 370 g/kg crude protein from red drum muscle and crystalline amino acids with incremental levels of Leu (9.0, 13.0, 17.0, 21.0, 25.0 and 29.0 g/kg of dry diet), Ile (5.0, 8.0, 11.0, 14.0, 17.0 and 20.0 g/kg of dry diet) and Val (6.8, 8.0, 9.2, 10.4, 11.6, 12.8 and 14.0 g/kg of dry diet). Fish were fed to apparent satiation twice daily in each trial, after which growth performance parameters were calculated and body composition and concentrations of BCAAs in plasma were analysed. Incremental levels of dietary Leu, Ile and Val significantly affected weight gain, feed efficiency and protein retention. Analyses of the weight gain data using a broken‐line regression model estimated the minimum Leu, Ile and Val requirements for maximum growth of juvenile red drum to be 15.7 ± 1.7 g/kg (±95% confidence interval), 11.1 ± 2.3 g/kg and 12.4 ± 0.6 g/kg of dry diet, respectively.     

Tibiotarsus bone characteristics and tibial dyschondroplasia incidence of broilers fed diets supplemented with leucine and valine

Two experiments were conducted to study the effect of standardized ileal digestible (SID) leucine and valine levels on tibiotarsus bone characteristics and the incidence of tibial dyschondroplasia of broilers from day 1 to 21 (Experiment I) and day 21 to 42 post‐hatch (Experiment II). Each experimental phase was evaluated independently. In both experiments, a total of 1,500 one‐day‐old Cobb 500 male broiler chickens were distributed in a completely randomized design 5 × 5 factorial arrangement for a total of 25 treatments. The SID leucine and valine levels were ranged from 10.0 to 19.6 g/kg, and 6.0 to 12.0 g/kg from day 1 to 21 post‐hatch, respectively, while day 21 to 42 post‐hatch ranged from 10.0 to 18.0 g leucine/kg, and 5.2 to 11.2 g valine/kg. Serum calcium and phosphorus, bone concentrations of calcium, phosphorus and ash, diameter and Seedor index of the tibiotarsus were not affected (p > .05) by the treatments at 21 or 42 days of age. There was an interaction (p ≤.06) between the SID levels of leucine and valine on tibiotarsus breaking strength at 21 days, but not at 42 days of age (p > .05). Tibiotarsus breaking strength was maximized in broilers from day 1 to 21 with the dietary levels of leucine and valine at 14.2 and 9.0 g/kg respectively. Dietary leucine levels reduced linearly (p < .05) the hypertrophic zone of tibiotarsus cartilage at 21 days of age. Therefore, leucine and valine supplementation interact positively on bone strength of broilers from day 1 to 21 post‐hatch. Leucine can be a useful amino acid for reducing the hypertrophic cartilage zone in broilers from day 1 to 21, but not from day 21 to 42 post‐hatch.     

Exploring the Potential of Icelandic Seaweeds Extracts Produced by Aqueous Pulsed Electric Fields-Assisted Extraction for Cosmetic Applications

A growing concern for overall health is driving a global market of natural ingredients not only in the food industry but also in the cosmetic field. In this study, a screening on potential cosmetic applications of aqueous extracts from three Icelandic seaweeds produced by pulsed electric fields (PEF) was performed. Produced extracts by PEF from Ulva lactuca, Alaria esculenta and Palmaria palmata were compared with the traditional hot water extraction in terms of polyphenol, flavonoid and carbohydrate content. Moreover, antioxidant properties and enzymatic inhibitory activities were evaluated by using in vitro assays. PEF exhibited similar results to the traditional method, showing several advantages such as its non-thermal nature and shorter extraction time. Amongst the three Icelandic species, Alaria esculenta showed the highest content of phenolic (mean value 8869.7 µg GAE/g dw) and flavonoid (mean value 12,098.7 µg QE/g dw) compounds, also exhibiting the highest antioxidant capacities. Moreover, Alaria esculenta extracts exhibited excellent anti-enzymatic activities (76.9, 72.8, 93.0 and 100% for collagenase, elastase, tyrosinase and hyaluronidase, respectively) for their use in skin whitening and anti-aging products. Thus, our preliminary study suggests that Icelandic Alaria esculenta-based extracts produced by PEF could be used as potential ingredients for natural cosmetic and cosmeceutical formulations.     

玉米胚乳不同糯质基因型对总淀粉及支链淀粉含量的影响

本试验研究了玉米胚乳的不同糯质基因型对总淀粉和支链淀粉含量的影响．试验选用普通玉米自交系Ａ（Ｂ３７）与糯质玉米自交系Ｂ１（齐４０１）、Ｂ２（辽糯４７０）配成两套组合,每套组合包含４种胚乳基因型（ＷｘＷｘＷｘ,ＷｘＷｘｗｘ,Ｗｘｗｘｗｘ,ｗｘｗｘｗｘ）．通过对两套组合淀粉含量的测定分析,结果表明：胚乳不同的糯质基因型对总淀粉含量没有显著影响;但是,随着隐性ｗｘ基因剂量的增加,支链淀粉含量呈显著性递度提高．