Effects of Echerichia coli lipopolysaccharides and dissolved ammonia on immune response in southern white shrimp Litopenaeus schmitti

The success of penaeid shrimp aquaculture has been limited by endemic and epidemic infectious diseases around the world and shrimp defense mechanisms are a priority for control, prevention, and diagnosis. The lethal dose (LD₅₀) of Escherichia coli lipopolysaccharides was calculated and pathogen injection and dissolved ammonia concentration on immune response were evaluated in southern white shrimp Litopenaeus schmitti. The lethal dose of lipopolysacharides was 3.78 mg kg^− 1 body weight. Injection caused changes in phenoloxidase activity in plasma and nitric oxide and total haemocyte counts within the first 24 h. High concentration of dissolved ammonia caused a decrease in haemocytes by 66% within the first 72 h, when compared to the control. Hemagglutination in plasma was not affected by injection or high concentrations of dissolved ammonia. The results showed that white shrimp recognized the lipopolysacharides and responded to this microbial elicitor, as indicated by a variety of immunological indicators and that increased dissolved ammonia affected the number of circulating haemocytes.     

Optimization of Ozonated Water Treatment of Wild-Caught and Mechanically Peeled Shrimp Meat

ABSTRACT

Ozone is a USFDA and USDA approved food contact sanitizing agent and has been used in the seafood industry in both gaseous and dissolved forms to destroy bacteria. The wild harvest shrimp industry is the most economically important fishery in the U.S. Gulf of Mexico region, and in Louisiana the majority of the harvest is mechanically peeled and frozen. Dissolved ozone was measured in processing water at product application to study the optimization of ozonated water treatment for reducing microbial contamination of peeled shrimp meat. Shrimp samples were either sprayed or soaked in water with 1, 2, and 3 ppm dissolved ozone. Treatment times of 20, 40, and 60 seconds were investigated for all applications and concentrations. Similar volumes of water were applied for all treatments, and soaking showed greater bacterial reduction than spray treatments for all time and concentration combinations studied. Soaking in 3 ppm dissolved ozone for 40 s and 60 s showed the greatest reduction of total aerobic bacteria, and 60 s at 3 ppm resulted in the greatest reduction of Pseudomonas bacteria. Ozonated water treatment did not produce oxidation in the shrimp samples. The optimal treatment of soaking shrimp in 3 ppm dissolved ozone for 60 s will be used for further investigations of refrigerated shelf life extension and Listeria monocytogenes destruction in peeled shrimp meat.     

免疫增强剂在虾类养殖上的应用现状和研究进展

从介绍虾类的免疫系统出发，阐述了虾类免疫增强剂的发展概况，对免疫增强剂在虾类养殖上的应用进行了总结和概括，并阐述了虾类免疫增强剂研究存在的问题和发展趋势。     

虾油和蟹油的理化特性研究

[目的]研究以螃蟹壳和虾头为原料提取的蟹油和虾油的理化特性。[方法]在常温和煎炸条件下,测定比较芝麻香油、豆油、虾油和蟹油的酸值、碘值和过氧化值,并对4种油的外观变化进行分析。[结果]试验表明,虾油和螃蟹油在常温下新鲜度高,在煎炸条件下氧化稳定性比豆油和芝麻香油稍差,且在煎炸40min后失去特征优势;在感官评价中,虾油和螃蟹油综合得分较高,但在油炸条件下优势不明显。[结论]研究可为虾油和蟹油的综合开发利用提供参考依据。     

几种对虾池塘放养模式的生态效益评价

从生态效益角度对我国对虾池塘的几种放养模式进行了评价，综合放养模式符合生态平衡、物种共生互利以及对物质多层次利用等生态学原理，较之于单品种放养模式具有较高的生态效益，在我国具有强大的生命力和广阔的发展前景。     

溴氯海因粉在淡水青虾和养殖水体中的代谢动力学研究

[目、的]研究溴氯海因粉在淡水青虾体内的药物代谢动力学。[方法]用8％溴氯海因粉全池泼洒（水体中含O．04mg／L溴氯海因）给药,每天1次,连续2d,采用有机萃取及固相萃取等方法提纯净化样本,用高效液相色谱法测定溴氯海因粉在淡水青虾体内和养殖水体中的代谢和残留。[结果]该方法所得的溴氯海因在0．10～20．00μg／ml内线性良好,最低检测限为0．05μg／ml;使用溴氯海因粉后4h淡水青虾的肌肉和血液中均未检出溴氯海因;8-48h内肌肉和血液中检出微量的溴氯海因,其中血液48h溴氯海因浓度为0．014μg／ml,肌肉为0．002μg／ml,72h后血液和肌肉中未检出溴氯海因。养殖水体中,溴氯海因降解符合一级反应,降解方程：C=0．396eμm,降解半衰期为35．76h。【结论】建议在25℃左右水温条件下,溴氯海因的休药期为3d。     

在受污染的日本对虾塘内建立卫生小丘的实验研究

省平潭县的虾塘大都建于８０年代之前，塘底严重淤泥化，近年来对日本对虾经常暴病暴死，我们在８．５亩的实验浅水虾塘内建立若干卫生小丘，供日本对虾越冬和白昼潜伏，延缓了日本对虾发病时间和提高了产量。     

Effects of Drying Condition on Physico-chemical Properties of Foam-mat Dried Shrimp Powder

ABSTRACT

The effects of drying parameters on moisture content, water activity, bulk density, water binding capacity (WBC), oil absorption, and color parameters (L*,a*, b*) of foam-mat dried shrimp powders were investigated. Shrimp purees were dried as a foam mat at different drying temperatures (50ºC, 60ºC, and 70ºC) and thicknesses of the foam layer (4 and 8 mm). The experimental results showed that as the temperature increased, the moisture content, water activity, and oil absorption of the samples decreased. However, their solubility increased significantly (P ?0.05). Bulk density of shrimp powder increased with increasing the thickness of the foam layer. Increasing temperature led to increased and decreased WBC with 4 and 8 mm thickness, respectively. Furthermore, the a*, b*, and L* (at 8 mm thickness) decreased with increasing temperature; however, L* increased at 4 mm thickness. Fourier transform infrared (FTIR) spectra showed some major shifts, such as in the region of 1000–1700 cm^?1, related to C–O, C–O–C, and C–H band stretching. The differential scanning calorimetry thermograms showed a large peak with a denaturation peak around 72ºC for shrimp proteins.     

虾废弃物中蛋白质的资源化利用

概述了国内外虾废弃物蛋白资源化利用的情况及工艺研发的现状,介绍了虾废弃物中蛋白质的存在形式、化学组成和微观结构,详细阐述了虾废弃物蛋白的等电点沉淀法提取以及化学法与酶法水解虾废弃物蛋白,利用微生物发酵转化虾废弃物,为实现虾废弃物的资源化、无害化利用提供了研究依据。     

对虾白黑斑病的防治技术研究

对虾白黑斑病已被证实为一种生理性疾病，与细菌等生物性病原没有直接关系。根据这一结果作者一改过去以抗菌素为主治疗该病的方法，而采取生成防中强对虾营养的措施，在实验室小水体及生产养虾池进行防治试验，取得了满意的结果。