Effect of shrimp head protein hydrolysates on the state of water and denaturation of fish myofibrils during dehydration

ABSTRACT:   To utilize fisheries waste products as food materials with functional properties, shrimp head protein hydrolysates (SHPH) from three species of shrimp, that is, Northern pink shrimp ( Pandalus eous ), Endeavour shrimp ( Metapenaeus endeavouri ) and Black tiger shrimp ( Penaeus monodon ), were produced by enzymatic hydrolysis using endopeptidase derived from Bacillus subtilis and exopeptidase derived from Aspergillus oryzae at a level of 0.1% (w/w). SHPH were rich in protein (90–91%) and amino acids (71–84%) but little fat (0.01–0.02%). The average molecular weight of SHPH was 300–1400. The effect of 5% SHPH (dry basis) addition on the state of water and denaturation of lizard fish myofibrils (Mf) during the dehydration process was evaluated by the desorption isotherm and the Ca-ATPase activity, and compared with the effect of sodium glutamate (Na-Glu). SHPH decreased the water activity and the Ca-ATPase inactivation, and increased monolayer sorbed water and multilayer sorbed water of Mf, although these effects of SHPH were smaller than those of Na-Glu. These findings suggest that the SHPH suppressed dehydration-induced denaturation of myofibrillar protein by stabilizing the hydrated water surrounding myofibrils.     

光合细菌在虾病防治中的作用研究

本文着重研究光合细菌(PSB)在虾病防治中的作用,结果表明:对虾养殖池施用光合细菌后,随PSB浓度的增加水质、底泥中弧菌和异养细菌数量而逐渐减少,表明了PSB具有调节和改善养殖的微生态环境的作用。PSB还能降低底泥中的有机质和硫化物含量,降低COD含量,并提高养殖水体的溶解氧,改善水生环境。本文还分析了PSB在长毛对虾幼体培育中的应用效果,光合细菌的营养通过食物链的传递,促进对虾生长,增强对虾抗病能力,降低发病率和死亡率。     

Incentive for shifts in water management systems by shrimp culturists in southern Thailand

ABSTRACT:   Water management systems and other business situations of shrimp culturists were surveyed in two districts in southern Thailand. There were three types of water management systems in southern Thailand, namely closed, semiclosed and open systems, categorized by the frequency of exchange of pond water. Shrimp culturists in those districts tended to shift their system from the open system to the closed system of their own accord, and the average net income ratio decreased due to the change of water management system in a district from more than 2 to less than 1. The reason for this shift, in spite of the decrease in the profit rate, was prevention of infectious disease caused by water exchange. In conclusion, it was proven that independent shrimp culturists, such as medium and small scale shrimp pond owners in southern Thailand, would accept short-term decreases in profit rate in order to stabilize production.     

湛江近海虾拖网虾蟹类渔获组成

在2012 年8 月进行的南海北部虾拖网海上调查的基础上,对虾蟹类渔获的种类组成、生物学特征和幼 体比例等进行了分析。结果显示,渔获种类一共71 种,其中虾蟹类15 种,但其产量却占总产量的82.34%;虾类优势 种为日本囊对虾（Marsupenaeus japonicus）、刀额新对虾（Metapenaeus ensis）、近缘新对虾（M. affinis）和周氏新对虾（M. joyneri）;蟹类优势种为红星梭子蟹（Portunus sanguinolentus）、三疣梭子蟹（P. trituberculatus）和远海梭子蟹（P. pelagicus）;刀额新对虾的幼虾比例为73.36%,三疣梭子蟹的幼蟹比例为78.79%。最后,探讨了促进南海虾蟹类资源 合理利用的措施。     

金融危机后全球对虾贸易格局与出口竞争力研究

受国际金融危机的影响,全球经济增长放缓,对虾市场也受到了一定的冲击.金融危机后,对虾贸易开始复苏,并仍然集中在亚洲、美洲和欧洲三大区域.其中,泰国、越南、中国、印度尼西亚、印度的对虾产品国际市场占有率较高,并对美欧日三大进口市场具有较高的渗透率;厄瓜多尔、越南、泰国、孟加拉的对虾出口竞争力很强;上述国家对虾产品的比较优势显著.通过对湛江国联水产出口经验的借鉴,为增强中国对虾出口竞争力提供了启示.     

3种对虾种间RAPD遗传标记

用RAPD技术对虾属中凡纳对虾、日本对虾和中国对虾基因组DNA的特异性遗传标记进行分析，筛选了OPK和OPE两个系列40个引物，有37个引物获得了片段长度在250-2200bp之间且重复性良好的谱带，其中34个引物均可以将1种、2种甚至3种对虾分别区别开来，共获得了264个扩增片段，其中3种对虾特异性片段95个，每个引物分别获得了1-7个大小不等的片段，凡纳对虾获得了28个特异性片段，日本对虾获得了32个特异性片段，中国对虾获得了35个特异性片段。通过Popgnen1.32种群遗传分析软件包计算结果表明：日本与对虾与中国对虾的遗传距离最大，高达0.9096；日本对虾与凡纳对虾的遗传距离次之，为0.8608；凡纳对虾与中国对虾的遗传距离最小，其值为0.6219。根据遗传距离指数，用UPGMA方法进行聚类分析，构建系统树。     

中国对虾（Penaeus chinensis）养成期虾池水体和底质及虾体异养菌和弧菌含量的变化

本文报道了辽宁省瓦房店市邓屯乡高家养虾场对虾养成期虾池水体和底质及虾体异养菌和弧菌含量的变化。结果表明外海水中异养菌数量为１０￣４～１０￣５个／毫升，弧菌数量为１０￣２～１０￣３个／毫升，虾池水中异养菌数量为１０￣４～１０￣５个／毫升，弧菌数量为１０￣２～１０￣４个／毫升，底质中异养菌数量为１０￣５～１０￣７个／克，弧菌数量为１０￣３～１０￣４个／克。虾体肌肉中异养菌数量为１０￣３～１０￣５个／克，弧菌数量为１０￣３～１０￣５个／克；肝胰脏中异养菌数量为１０￣３～１０￣７个／克，弧菌数量为１０￣２～１０￣７个／克；肠道中异养菌数量为１０￣６～１０￣７个／克，弧菌数量为１０￣６～１０￣７个／克。     

象山港放流虾群亲虾的产卵回归和生物学性状

象山港放流对虾主群在浙江岛礁外侧海区越冬后,翌年春随着温度回升逐步向沿岸回归,回归路线大致与浙江海岸线垂直,主群出现在象山港口的六横南部及三门湾口部海域。少量亲虾在港内越冬。亲虾的交配率达99.7%,性腺发育正常,体长组成与黄渤海亲虾一致。为浙江近海自然繁殖提供了优质的亲虾基础。     

皮下及造血组织坏死杆状病毒对中国对虾亲虾的人工感染

皮下及造血组织坏死杆状病毒对中国对虾亲虾的人工感染宋晓玲，黄倢，王崇明，于佳，陈碧鹃，杨丛海（黄海水产研究所，青岛２６６０７１）关键词中国对虾，亲虾，皮下及造血组织坏死杆状病毒，人工感染，温度效应ＡＲＴＩＦＩＣＩＡＬＩＮＦＥＣＴＩＯＮＯＦＢＲＯＯＤＳ...     

Litopenaeus vannamei (Boone) post-larval survival related to age, temperature, pH and ammonium concentration

Transport of post‐larvae shrimp used in aquaculture is an important element of successful cultivation because of the potential for stress during stocking procedures. To find optimum transport conditions, several bioassays were performed in the laboratory to evaluate survival of whiteleg shrimp Litopenaeus vannamei 5–30‐day‐old postlarvae under conditions similar to those encountered during transport from the hatchery to nursery and shrimp ponds. Postlarvae were exposed for 4 h to different temperatures and pH levels ammonia concentrations. Survival was significantly reduced after a 4 h exposure to pH 9 and was inversely related to temperature with or without 7 mg L^?1 of ammonia. The 15‐ and 20‐day‐old postlarvae had higher survival rates than other ages. The lowest survival occurred in alkali conditions (pH 9), with 7 mg L^?1ammonia at 30 and 32°C. To assure optimal survival of postlarvae during transfer from the hatchery to the nursery and shrimp ponds, we recommend temperatures below 28°C, pH no higher than 8, no ammonia and post‐larval age at least 15 days.