CMC在缢蛏涂覆保鲜上的应用研究

采用羧甲基纤维素钠（CMC）作为缢蛏（Sinonovacula constricta）保鲜涂覆胶,在5℃下保藏7 d,以缢蛏的活泼度、成活率、水分蒸发量及挂胶量等为指标对其保鲜效果进行评价。试验结果表明,采用CMC保鲜胶涂覆的缢蛏,5℃下7 d的成活率为100%,而对照组的成活率为60%,涂膜处理能降低水分蒸发速度,保鲜效果显著。     

海藻酸钠/浒苔多糖复合膜的制备及性能

为探讨海藻酸钠与浒苔多糖的协同作用,本研究首次以海藻酸钠和浒苔多糖为基材,甘油为增塑剂制备生物降解复合膜,探究了海藻酸钠与浒苔多糖质量比、共混溶液总浓度、甘油含量对复合膜拉伸强度、断裂伸长率、水蒸气透过率和水溶性的影响,同时,利用扫描电子显微镜技术(SEM)、傅里叶红外光谱(FTIR)进行微观结构表征。结果显示,海藻酸钠与浒苔多糖之间具有良好的相容性和协同作用,无明显的相分离现象。组分质量比、共混总浓度和甘油含量均对膜性能有较大影响,其中,质量比影响最显著,添加适量浒苔多糖可提高海藻酸钠膜的拉伸强度和断裂伸长率,降低海藻酸钠膜的水蒸气透过率,但膜水溶性略微提高。在组分质量比为8∶2时,膜拉伸强度从99.22 MPa增加到108.41 MPa,断裂伸长率从5.14%增加到6.20%,水蒸气透过率从6.445×10–11 g/(m·s·Pa)降低到6.027×10–11 g/(m·s·Pa),复合膜的综合性能达到最优。进一步优化了共混总浓度和甘油含量,最佳共混总浓度为1.6%(m/v),最佳甘油含量为0.9%(m/v)。本研究表明,浒苔多糖的添加增强了海藻酸钠膜的机械性能和阻隔性能。     

用敌百虫+面碱治疗池塘指环虫病的报告

据调查,泰宁县几乎80%的鱼病源自于寄生虫危害,特别是近年来指环虫病对鱼类的危害越来越严重,且各种杀虫药的治疗效果都不理想,杀虫不彻底,容易复发。2008年8月中旬,一口以培育蒲江Ⅰ号团头鲂鱼种的池塘暴发鱼病。8月16日开始出现死鱼10多尾,8月17至19日死鱼30多尾,8月20日猛增     

Inactivation of Ichthyophonus spores using sodium hypochlorite and polyvinyl pyrrolidone iodine

Chlorine and iodine solutions were effective at inactivating Ichthyophonus spores in vitro. Inactivation in sea water increased directly with halogen concentration and exposure duration, with significant differences (P < 0.05) from controls occurring at all chlorine concentrations and exposure durations tested (1.5–13.3 ppm for 1–60 min) and at most iodine concentrations and exposure durations tested (1.2 ppm for 60 min and 5.9–10.7 ppm for 1–60 min). However, 10‐fold reductions in spore viability occurred only after exposure to halogen solutions at higher concentrations and/or longer durations (13 ppm total chlorine for 1–60 min, 5.9 ppm total iodine for 60 min, and 10.7 ppm total iodine for 1–60 min). Inactivation efficacy was greater when halogen solutions were prepared in fresh water, presumably because of combined effects of halogen‐induced inactivation and general spore instability in fresh water. The results have practical implications for disinfection and biocontainment in research laboratories and other facilities that handle live Ichthyophonus cultures and/or infected fish.     

抗菌性海藻酸钠涂膜在罗非鱼片保鲜中的应用

采用测定涂膜抑菌性能、缓释效果来探讨抗菌性海藻酸钠涂膜的抑菌机理并将其应用在罗非鱼片的涂膜保鲜中。实验结果表明,抗菌膜是一种具有缓释效果的保鲜膜,对大肠杆菌Esche-richia coli、金黄色葡萄球菌Staphylococcus aureus、枯草芽孢杆菌Bacillus subtilis、腐败希瓦氏菌Shewanella putrefaciens及鱼片表面其他杂菌均有较好的抑制效果,保鲜剂在40h内可从涂膜中完全释放;与未经涂膜处理的对照组相比,抗菌膜可以明显控制鱼片细菌总数的增长、维持较低的挥发性盐基氮值和改善鱼片的感官质量,综合考虑鲜度指标并本着以感官评分为基础的原则,抗菌涂膜处理可以将罗非鱼片的保鲜期延长约5.5d。     

丁酸钠对鲟鱼幼鱼摄食及生长的影响

为了解丁酸钠对西伯利亚鲟(Acipenser baeri)幼鱼摄食及生长的影响。共设计了五个不同的丁酸钠水平,按照0、1、2、3、4、5 g/kg的含量分别添加到鲟鱼饲料中,正式试验期为60 d。结果表明:添加1 g/kg及以上剂量丁酸钠组的鱼体末均重、特定生长率和相对增重率显著高于对照组(P≤0.05),而各处理组间均无显著差异(P>0.05);饲料中添加丁酸钠对西伯利亚鲟幼鱼的摄食率和肝体比均无显著影响(P>0.05)。因此,本实验条件下配合饲料中添加丁酸钠能有效提高西伯利亚鲟幼鱼的生长性能,其最适添加剂量为1 g/kg。     

丁酸钠对鲫鱼生长和肠细胞增殖的影响

以初始体质量(6.02±0.16) g的鲫鱼(Carassius auratus)为研究对象, 在鲫鱼基础饲料中分别添加0.0 g/kg、1.0 g/kg、2.5 g/kg、5.0 g/kg、7.5 g/kg的包膜丁酸钠, 配制5种等氮等能的实验饲料, 研究不同浓度包膜丁酸钠通过促进鲫鱼肠细胞增殖对其生长作用的影响。实验在室内养殖系统中进行, 每水族缸饲喂30尾, 每处理组3个重复, 以鱼体质量3%~5%投喂量, 日投喂3次, 试验持续7周。实验结果表明: 在饲料中添加丁酸钠对鲫鱼有明显的促生长作用, 显著提高了鲫鱼前肠绒毛高度/隐窝深度的比值以及肠道细胞增殖因子CREB和CDX2基因的表达。当丁酸钠添加量为2.5 g/kg时, 鲫鱼增重率、特定生长率、蛋白质效率和肥满度最高, 显著高于对照组(P<0.05), 比对照组分别提高了25.76%、16.46%、28.91%和8.37%; 与对照组相比, 丁酸钠添加量达到2.5 g/kg时, 鲫鱼干物质与蛋白质表观消化率、前肠绒毛高度、肠道CREB基因和CDX2基因的相对表达量显著升高, 分别比对照组提高8.36%、6.21%、34.22%、51.11%和42.13%(P<0.05)。上述研究表明饲料中添加适量的丁酸钠可能通过显著提高鲫鱼肠绒毛高度和肠道细胞增殖因子CREB和CDX2基因的表达量, 从而促进其生长, 适宜添加量为2.5 g/kg。

     

Role of sodium bicarbonate on the initiation of sperm motility in the Japanese eel

ABSTRACT:   In order to find out the role of sodium bicarbonate (NaHCO₃) on the initiation of sperm motility in the Japanese eel Anguilla japonica , interactions were investigated between NaHCO₃ and various reagents (K⁺ channel blocker 4-aminopyridine [4-AP], ammonium chloride [NH₄Cl], sodium acetate and calcium chloride [CaCl₂]) that could regulate internal factors (intracellular K⁺, intracellular pH [[pH]_i] and intracellular Ca²⁺) in sperm motility. Contradictory effects of NaHCO₃ were observed (i.e. an inhibitory effect when 4-AP was absent and a promoting effect when 4-AP was present). Sodium bicarbonate inhibited the initiation of sperm motility in the Japanese eel. However, NaHCO₃ restored the motility of immotile sperm that 4-AP inhibited. The inhibitory effect of NaHCO₃ disappeared with the addition of NH₄Cl, which raised [pH]_i, but the promoting effect was not affected by [pH]_i. Although NaHCO₃ recovered motility in the presence of 4-AP, this recovery was also observed with the addition of CaCl₂ instead of NaHCO₃. In the initiation of sperm motility in the Japanese eel, two roles for NaHCO₃ are suggested: an inhibitory role relating to the regulation of [pH]_i and a promoting role relating to the uptake of another initiation factor, which could be Ca²⁺.     

磺胺间甲氧嘧啶钠对厚颌鲂幼鱼SOD活性和MDA含量的影响

以(30±2.3)g/尾的厚颌鲂(Megalobrama pellegrini)幼鱼为研究对象,采用一次性胸腔注射法,通过观察磺胺间甲氧嘧啶钠对厚颌鲂幼鱼超氧化物歧化酶(SOD)活性和丙二醛(MDA)含量的影响,探讨磺胺间甲氧嘧啶钠对厚颌鲂幼鱼各组织酶活性的影响变化及其休药期。结果显示,在同一浓度下,随着给药时间的延长,肝脏、肌肉和鳃组织SOD活性出现先降后升再降的趋势,而随着浓度的增加,则出现先升后降的趋势;肝脏、肌肉和鳃组织MDA,随着给药时间的延长和浓度的增加,均出现先升后降的趋势;厚颌鲂各组织SOD和MDA受磺胺间甲氧嘧啶钠影响最小的是肌肉,其次是鳃、肝脏;通过SOD和MDA变化情况,确定休药期为28 d左右。     

Use of sodium bicarbonate as an inexpensive general anesthetic for juvenile red tilapia hybrids

International Aquatic Research - In the context of responsible handling and good welfare practices, fish must be anesthetized to lessen the effects of the stressors to the fish. There are a number...     

海水网箱网衣碱性硅酸盐防污涂料的初步研究

本文以碱性硅酸盐为主防污剂,开发了一种防污期长、无毒、环保且高效的海水网箱网衣防污涂料：涂有该种防污涂料的试验网衣于2002年4月开始进行浅海挂网试验．为期七个月;每月一次定期对试验网片进行附着情况检查、拍照及称重。结果证明．与对照组相比,涂有硅酸盐防污涂料的网衣材料的网片增重及被附着的面积百分比均有大幅度的降低;实拍照片也证明涂有防污涂料的网片具有极佳的防污效果：根据试验结果,讨论了影响防污涂料防污效果的诸多因素。     

包膜硫酸钠/过氧化氢/氯化钠加合物在南美白对虾养殖上的应用

对包膜硫酸钠/过氧化氢/氯化钠加合物进行稳定性和释放性能进行分析,结果发现:该物质在空气中敞开放置10d后过氧化氢分解率只有0.62%;该物质投放进水中后迅速释放出过氧化氢,10min过氧化氢的释放率达到18.6%,10h后过氧化氢的释放率为82.4%。将该物质应用在南美白对虾养殖上,结果表明:试验开始后,对照池和试验池的溶氧均呈上升趋势,试验池中的溶氧比对照池上升的幅度大;与对照池相比,试验池中的氨氮、亚硝酸盐氮、硫化物、化学耗氧量和细菌数量呈下降趋势,pH值没有明显的变化;该物质对养殖水体的作用效果持续10h以上。     

饲料中添加氯化钠对草鱼生长性能和肌肉品质的影响

为研究饲料中添加氯化钠对草鱼生长性能和肌肉品质的影响,在基础饲料中分别添加0（对照组）、10、20、30和40 g/kg氯化钠,配制成5组饲料,饲养平均体质量为（12.26±0.03） g的草鱼60 d。结果显示,添加10和20 g/kg氯化钠对草鱼增重率和饲料系数没有显著影响,但30和40 g/kg氯化钠添加组的增重率显著低于对照组,饲料系数显著升高。各组肌肉水分、粗蛋白与粗脂肪含量没有显著差异,但肌肉灰分含量随氯化钠添加量的增加而升高;与对照组相比,各氯化钠添加组的肌肉蒸失水率、离心失水率和冷冻失水率（除10 g/kg氯化钠添加组外）显著增加,10和20 g/kg氯化钠添加组的肌肉总游离氨基酸含量显著升高,20、30和40 g/kg氯化钠添加组的肌肉游离谷氨酸、天冬氨酸含量显著降低;各氯化钠添加组的肌肉硬度及30、40 g/kg氯化钠添加组的肌肉咀嚼性均显著低于对照组,而肌肉弹性和回复性无显著差异;在肠道组织学方面,30和40 g/kg氯化钠添加组的绒毛高度和绒毛宽度较对照组显著降低,各氯化钠添加组的肌层厚度显著增加。研究表明,在饲料中添加10~40 g/kg氯化钠,对草鱼幼鱼的生长性能和肌肉品质没有改善作用。     

Evaluation of sodium percarbonate as a bath treatment for amoebic gill disease in Atlantic salmon

Amoebic gill disease (AGD), caused by Neoparamoeba perurans, is a major health challenge for Atlantic salmon aquaculture globally. While freshwater bathing for 2 hr is effective in reducing infection severity, there is need for more rapid and lower cost alternatives. To this end, a combination of sodium percarbonate (SPC) in freshwater was examined for its treatment efficacy. Initial in vitro studies showed a reduction in amoeba viability when exposed for 30 min to freshwater containing >500 mg/L SPC. Subsequently, AGD‐affected salmon were bathed for 30 min in 16°C freshwater containing 100, 500 or 1,000 mg/L SPC, or for 2 hr in 16°C freshwater to mimic industry practice. Treatment at the highest SPC concentration caused extensive gill damage and substantial mortality. Neither occurred to a significant extent at lower SPC concentrations. Gill pathology of surviving fish 10 days post‐treatment (dpt) was comparable to or more severe than pre‐treatment, and significantly (p < .001) more severe than in 2 hr freshwater bathed fish. N. perurans DNA was confirmed by qPCR in all treatment groups at 10 dpt. The data indicate that a 30‐min exposure to SPC in freshwater is not a suitable alternative to existing freshwater treatment of AGD.     

枯草芽孢杆菌与腐植酸钠合剂净水效果的研究

养殖水体中高含量氨氮和亚硝酸盐对水产动物有害。试验通过不同配比腐植酸钠与枯草芽孢杆菌(Bacillus subtili)混合剂处理模拟养殖污水,结果表明养殖水体投入10 mg/L腐植酸钠与1.2×10~3 cfu/mL枯草芽孢杆菌混合剂对水体中氨氮和亚硝酸盐的处理效果较好。     

高压钠灯在阿拉伯海鸢乌贼钓捕中的应用效果

20 0 3年 10月 ,在阿拉伯海鸢乌贼渔场中对鱿钓船的舷侧水中光照度进行了实测。本文结合试验船的尺寸数据和当时的渔获生产统计数据 ,对使用高压钠灯 (也称变色灯 )时的光照度分布及其使用前后的钓捕效果进行了比较分析。在 12 0盏× 2kW金属卤化物灯作用下 ,在距船右舷 3 0m的垂直断面 ,0 0 1lx的等光照度曲线在 5 5m水层附近 ;但在 2 0盏× 5 0 0W高压钠灯作用下 ,0 0 1lx的等光照度曲线在 2 0m水层附近。采用高压钠灯可以使鱿鱼聚集密度增大 ,钓捕深度变浅 ,从而提高渔获效率 ,其每小时平均产量比采用高压钠灯前高 1～ 6 5倍。     

Efficacy of formalin, hydrogen peroxide, and sodium chloride on fungal-infected rainbow trout eggs

Antifungal agents are essential for the maintenance of healthy stocks of fish and their eggs in intensive aquaculture operations. In the USA, formalin is the only fungicide approved for use in fish culture. However, hydrogen peroxide and sodium chloride have been granted low regulatory priority drug status by the United States Food and Drug Administration (FDA) and their use is allowed. We evaluated the efficacy of these fungicides for controlling fungal infections on rainbow trout eggs. A pilot study was conducted to determine the minimum water flow rate required to administer test chemicals accurately in Heath incubators. A minimum water flow rate of 7.6 1 min⁻¹ was necessary to maintain treatment concentrations during flow-through chemical exposures. The antifungal activity of formalin, hydrogen peroxide, and sodium chloride was evaluated by treating uninfected and 10% fungal-infected (Saprolegnia parasitica) rainbow trout eggs (Oncorhynchus mykiss) for 15 min every other day until hatch. There were no significant differences among treatments in percent hatch or final infection for uninfected eggs receiving prophylactic chemical treatments. Eggs of the negative control group (uninfected and untreated) had a mean hatch exceeding 86%. All chemical treatments conducted on the infected egg groups controlled the spread of fungus and improved hatching success compared with the positive control groups (infected and untreated). Formalin treatments of 1000 and 1500 μl l⁻¹ and hydrogen peroxide treatments of 500 and 1000 μl l⁻¹ were the most effective. Sodium chloride treatments of 30 000 mg l⁻¹ improved fry hatch, but the compound was less effective at inhibiting fungal growths compared with hydrogen peroxide and formalin treatments.     

包膜硫酸钠/过氧化氢/氯化钠加合物对尼罗罗非鱼养殖水体的改善效果

选取经食盐水浸浴10 d后平均体重为40 g左右的健康尼罗罗非鱼,随机分成两组,一组为对照组.另一组为试验组,每组设3个重复,每个重复30尾,饲养于水族箱中.试验组按3 g/m3水的添加量投放包膜硫酸钠/过氧化氢/氯化钠加合物,每2 d投放1次,试验期20 d,试验期间不换水,24 h增氧,每天两次投饵,不捞残饵,研究包膜硫酸钠/过氧化氢/氯化钠加合物对尼罗罗非鱼养殖水体的改善效果.结果表明,(1)试验组和对照组水体的溶氧和pH值没有明显的差异;试验组和对照组氨氮、亚硝酸盐氮和COD浓度均随着试验时间的延长而升高,相同时间点试验组水体氨氮、亚硝酸盐氮和COD浓度均低于对照组,其中氨氮在第12、15和20天达到显著水平(P＜0.05),亚硝酸盐氮和COD在第9、12、15和20天达到显著水平(P＜0.05);(2)与对照组相比,试验组养殖水体细菌数量显著降低(P＜0.05);(3)与对照组相比,试验组尼罗罗非鱼日增重、特定生长率和存活率分别提高40%(P＜0.05)、40.9%(P＜0.05)和14.2%(P＜0.05),饵料系数降低12.3%(P＜0.05).