养殖南美白对虾要具备良好的水质理化因子指标

水质调控是养虾中心环节，有没有良好的水质，决定了养虾的成败。养殖南美白对虾，需要具备以下良好水质理化因子指标：     

沙颍河周口市段水质的生物学监测及评价

对沙颍河周口段水质进行检测，包括微生物学检测、叶绿素a测定等，结合理化检测对其水质做出初步评价。结果表明大闸上游段水质为β中污带，贫营养型；胜利桥段水质为α-中污带，中营养型；地区医院段水质为多污带，属富营养型。     

家鱼养殖中池塘水质的调节控制

养鱼先养水。鱼类终身生活在水中，能否有一个“肥、活、爽、嫩”和良好水质条件，是决定鱼摄食与生长的关键因素。在家鱼养殖中，可以通过水色、底泥颜色及水体理化指标等的变化来判断池塘水质的好坏，并且根据其变化情况合理进行调节，保持池塘水质良好。本文就家鱼养殖中池塘水质调节控制技术进行了论述。     

真鲷养殖所需要的理化水质必要的参数

为了确定真鲷适宜的养殖水域，因此必需考虑到环境各种因子．养殖环境因子，通常包括水流、温度、盐度以及理化因子等．严格控制水质，是真鲷养殖获得成功最重要的一个方面．尽管通过研究巳证实，真鲷对各种理化因子具有很高的忍耐范围，但有一些作为必要的限制因子。     

营口咸水河及其供水虾池水环境研究初报

１９９３年以来，营口咸水河区域养虾业受到病害侵袭，但却一直保持较高产量并盈利。本文对咸水河及其供水虾池的水质理化指标、浮游生物、细菌总数进行了测定分析，证明该区域水质良好，同时对咸水河水环境特点及虾病发生的原因进行了初步探讨。     

营口对虾养殖示范区水化学状况

作者对营口对虾养殖示范区的水源（咸水河）及养殖池的水化学状况进行了定期监测，１９９５～１９９７年每年于６～８月份对水质理化指标、浮游生物、细菌总数测定分析。初步探讨了水质变化与虾病发生的关系。     

西泉眼水库水质分析及评价

本文根据1998年对西泉眼水库水质的理化性状测定分析结果，进行了简析和评价，为该水库发展渔业生产提供科学依据。     

池塘养殖水体改良与调控技术的新进展

从池塘良好水质的一般特征、池塘良好水质的理化和生物指标、调节池塘水质的主要措施和改善池塘水环境的技术发展等方面论述了池塘养殖水体改良与调控技术的新进展。     

欧洲鳗鲡池塘养殖水质理化因子周年变化的初步研究

本试验以欧洲鳗鲡为研究对象,对不同放养密度的欧鳗池塘的氮、磷营养元素等8个水质理化因子进行周年的监测与分析,着重从水质理化因子与欧鳗养殖的相关性方面进行研究,以期为欧鳗土池养殖水环境调控提供科学理论依据.     

一起管理不当引起越冬鱼类患水霉病的实例

正2018年3月26日,盘山县一个成鱼越冬户,越冬成鱼面积80亩,共计4个池塘,其中一号池塘面积26亩,在池塘冰基本全部化开时,发现池塘越冬的成鱼身上长有许多毛,患有较重的水霉病。经过化验水质理化指标,水质常规理化指标均比较正常,水色浓黄绿色,相对其他池塘水质过肥,水中溶氧含量达到23毫克/升。越冬的成鱼没有发现这种现象,其他三个池塘经过水质理化指标监测以及水中溶解氧的检测,最高水中溶解     

微生态净水剂对凡纳滨对虾生理生化指标的影响

为了证实微生态净水剂(含菌量10×109/g)可以提高虾体免疫力和对污染物(如农药)的抵抗力,在凡纳滨对虾(Litopenaeus vannmei)养殖过程中,设置了施用微生态净水剂的实验组和未用微生态净水剂的对照组,采用肌肉注射的方式,对2组凡纳滨对虾进行乙酰甲胺磷毒性实验。注射乙酰甲胺磷后,采样测定血细胞吞噬化学发光情况,组织中超氧化物歧化酶(SOD)、过氧化物酶(POD)、溶菌酶(LSZ)、酯酶活性以及酯酶(EST)、苹果酸脱氢酶(MDH)同工酶表型变化。结果表明:施用微生态净水剂组明显好于对照组。施用微生态净水剂的虾注射乙酰甲胺磷后死亡率降低,血细胞的吞噬功能也有所增加,虾体组织内SOD、POD、LSZ、酯酶活性变化较未用组的虾变化幅度较小,其中,SOD、POD活性等高于未用组,EST、MDH同工酶酶带数目也有增加。说明微生态净水剂从本质上增强虾体内代谢、提高虾体的免疫力、增强其对外界环境变化适应能力,并具有提高虾体防御功能,增强抵抗疾病能力的作用。     

对虾发光病生物防治技术的初步研究

本文探讨了应用哈维氏弧菌噬菌体对致病菌哈维氏弧菌(Vibrio harveyi)的特异性噬菌作用防治对虾发光病的必要性和可行性.实验表明:从对虾育苗场分离的对虾发光病致病菌哈维氏弧菌对46种抗菌药物的敏感性逐年减弱,1993年尚有28种敏感药物,其中中度以上敏感的有12种;而到了2003年敏感药物则只剩下9种,中度敏感的仅为头孢三嗪和壮观霉素2种,在养殖生产中常用的几种药物几乎都变为不敏感.在试验水体中添加该噬菌体可使哈维氏弧菌的数量减少2～3个数量级,可以相对减少对虾发光病的发生和虾苗的死亡.实验还显示试验虾苗的死亡与噬菌体的效价高低无关,而与加入的噬菌体上清液的有机质含量有关.     

褐藻酸钠裂解物对冷冻南美白对虾品质的影响

以褐藻酸钠为原料,采用过氧化氢氧化法制备褐藻酸钠裂解物,分析了裂解物对南美白对虾Penaeus vannamei虾仁质量的效果,并研究了对虾仁冷冻后品质的影响.结果表明,褐藻酸钠裂解物中的分子量大于6 kDa的裂解物HDX-A能有效改善冷冻后水分流失,虾仁经1％的浸泡液处理1h后进行冻藏不同时间后再解冻,HDX-A能够有效地阻止水分流失,从而保持虾仁水分且随时间的延长其保持能力并不减弱,而且随浸泡溶液浓度的增加效果增强.HDX-A主要是通过增加自由水含量而避免了冷冻后虾仁水分和营养流失.HDX-A还可有效地降低冷冻虾仁的蒸煮损失,1.5％处理的样品蒸煮损失最低,整体上蒸煮损失低于20％,120d时仅为15.6％左右,显著低于对照(P＜0.05).HDX-A可通过降低冷冻虾仁水分流失改善了粘弹性和破断力等流变学特性,提高了产品品质,可作为无磷品质改良剂替代复合磷酸盐.     

不同养殖措施防治对虾暴发性流行病效果的初步研究

利用水泥池、土池及不同水处理方法等不同措施养殖对虾，研究养殖升旗与对虾暴发性病毒发生的关系，探讨合理养殖模式。试验结果表明，利用水泥池、沙滤水、封闭式循环水养殖和使用防病药物等措施对防治暴发性疾病都有一定的效果；使用优质饵料强化对虾体质，合理使用防病药物及水质净化剂，优化养殖生态环境对增强对虾抗病能力有效；虾池内放养部分肉食性鱼类能延缓对虾发病时间。     

Manufacturing Different Diet Sizes and Its Effect on Pellet Water Stability and Growth of Three Size Classes of Pacific White Shrimp,Litopenaeus vannamei

Abstract

A feed manufacturing method involving the production of large pellets followed by crumbling to desired diet sizes was used to produce six shrimp diets to determine its effect on growth of three size classes of Pacific white shrimp, Litopenaeus vannamei. The six diets containing 45% protein were 0.7 mm crumble, 1.2 mm crumble, 1.7 mm crumble, 2.2 mm crumble, 2.6 mm crumble, and 3.0 mm pellet. These diets were fed to three size classes of shrimp subjected to a four-week growth trial under indoor laboratory conditions. Stocking density was 12 shrimp/aquarium for size class 1 (1.13iö.01 g), 9 shrimp/aquarium for size class 2 (7.31iö.06 g), and 6 shrimp/aquarium for size class 3 (13.12iö. 10 g). Shrimp were fed three times daily and were evaluated for live weight, growth rate, feed conversion ratio (FCR), and survival. Results for shrimp growth appeared to be affected by diet size and pellet water stability. The effects of diet size, however, were more evident on smaller sized shrimp. Weekly growth rates for class 1 and class 2 shrimp indicated significant responses (P < 0.05) to the effects of diet size, while the class 3 shrimp did not show any significant result. The growth rates for both class 1 and class 2 shrimp were lowest at the smallest diet size (0.7 mm crumble) but differed with respect to highest growth rates. The largest diet (3.0 mm pellets) yielded the highest growth rates for class 1 shrimp, while medium sized feed (2.2 mm crumble) produced the best growth for class 2 shrimp. This could be partly attributed to pellet water stability, which had a direct correlation to diet size (r = 0.97). Smaller diet sizes resulting from crumbling larger pellets tend to have lower water stability. The water stability decreased from 82.5% to 76.3% as the 3.0 mm pellets were reduced to 0.7 mm crumbles. Stress cracks are created during crumbling, and surface area to volume ratio are increased as larger particles are reduced to crumbles. These would make smaller diet particles more susceptible to disintegration and nutrient leaching. For class 3 shrimp, the largest pellets produced the highest growth rate. This high growth value, however, was not significantly different (P > 0.05) from growth results produced by the crumbled feed sizes. This observation suggests that diet sizes ranging from 0.7 mm crumble to 3.0 mm pellet could be used for a 13 g shrimp, although preference would be given to larger pellets due to higher growth performance and better pellet water stability. Results for shrimp live weights were similar to results obtained for weekly growth rates. FCR and survival of all shrimp sizes did not show any significant response from the effects of various diet sizes. However, larger shrimp were less efficient in their diet utilization than smaller shrimp.     

Effect of a size-based selection program on blood metabolites and immune response of Litopenaeus vannamei juveniles fed different dietary carbohydrate levels

Blood metabolites in wild and seventh-generation cultivated shrimp were measured to determine how size-based selection could alter the nutritional and immunological conditions of Litopenaeus vannamei. Wild L. vannamei juveniles and a sample of seventh-generation cultured shrimp were acclimated under identical conditions. During 55 days, shrimp were fed a high (HCHO: 44%) or a low (LCHO: 3%) carbohydrate diet for 55 days. Wild shrimp showed a direct relation between dietary CHO and lactate, protein and hemocyte levels indicating that dietary CHO was used for protein synthesis via transamination pathways. In seventh-generation cultured shrimp these parameters were inversely proportional to dietary CHO level, indicating the capacity to synthesize protein from dietary CHO was repressed in cultured shrimp. Farmed shrimp showed a limited capacity to respond to LCHO diets demonstrating high protein dependence in their metabolism and immune response. These results demonstrate that during size-based breeding programs other metabolic process than CHO catabolism can be selected. The incapacity of shrimp to use dietary CHO could limit protein reduction of diets and limit the efforts of the shrimp industry to be ecologically and environmentally profitable.     

４种微生态制剂对虾池水质及青虾生长性能的影响

在测定养殖水体pH值、溶解氧、氨态氮、亚硝态氮等水质指标和养殖青虾肥满度、平均规格、饲料系数等生长性能指标的基础上,比较研究了全池泼洒复合芽孢杆菌、EM菌、类球红细菌、超浓缩光合细菌微生态制剂对养殖水质的改善情况及提高杂交青虾"太湖1号"生长性能的效果。结果表明,4种微生态制剂均可改善水质;其中,芽孢杆菌与EM菌具有较强的降亚硝态氮功能,类球红细菌和EM菌具有较强的降氨态氮作用。4种试验菌剂的调水效果排序为:类球红细菌>EM菌>复合芽孢杆菌>超浓缩光合细菌。4种菌剂不同程度提高了青虾的生长性能;其中,类球红细菌效果最为显著,其次为EM菌、复合芽孢杆菌,而光合细菌的效果不显著。     

酵母饲料添加剂在对虾育苗中的应用

在对虾育苗生产中试验了啤酒酵母饲料添加剂对育苗效果和防治发光细菌的作用。结果表明，无论是作为对虾幼体饵料添加剂或是作为水质改良剂，啤酒酵母饲料添加剂具有抑制病菌生长繁殖，提高对虾育苗存活率的作用。     

Marine shrimp aquaculture: a novel waste treatment system

Ecuadorian Penaeus vannamei were cultured in dirt ponds (each of approximately 163 m²) at four different stocking densities, i.e. 5 shrimp m⁻², 10 shrimp m⁻², 15 shrimp m⁻² and 20 shrimp m⁻². Experiments were carried out over three different periods during the year. Each experiment lasted for 11–14 weeks. No commercial feed was given to the shrimp. The only input to the ponds was about 30 kg of cattle manure per pond per week. Chemical composition of the cattle manure was analyzed. Water quality parameters such as temperature, pH, DO and turbidity were recorded twice daily for each experiment; nutrients (nitrite, nitrate, ammonium and phosphate), water ATP, sediment ATP, H₂S and chlorophyll were measured twice weekly for each experiment. Shrimp were sampled either weekly or bi-weekly for body weight measurements.

The results showed a negative correlation between stocking density and growth. Weekly growth ranged from 0·44 to 1·58 g week⁻¹. Survival was over 50% in all treatments and averaged at 70·8%. Under these stocking densities, shrimp production ranged from 4·4 to 18·8 kg ha⁻¹ day⁻¹. The stocking density of 15 shrimps m⁻² provides better production than the other stocking densities.

Water quality data did not relate to any shrimp growth. Water nutrient levels in pond discharge water were less than or equal to the nutrients in the incoming water in spite of the weekly addition of cattle manure and did not increase with the addition of cattle manure. No coliform bacteria were detected in any pond water samples through the study period. This indicates digestion of cattle manure in marine shrimp ponds would not pollute the environment with high concentrations of dissolved nutrients.

Thus, a marine shrimp pond can be considered a dissolved nutrient marine treatment plant converting unwanted cattle manure (1841 kg cattle manure ha⁻¹ week⁻¹ in this study) into a valuable commodity — shrimp.     

“Summer syndrome” in Litopenaeus stylirostris grow out ponds in New Caledonia: Zootechnical and environmental factors

The “Summer Syndrome”, a septicemic vibriosis caused by Vibrio nigripulchritudo, is responsible for one of the two main seasonal mortalities which affect shrimp aquaculture in New Caledonia. It was identified for the first time in December 1997 in an intensive shrimp farm (called farm DF) and has been enzootic ever since. The “Summer syndrome” affects shrimp during warm-season growout. Although the geographic area concerned is limited, it is a potential threat for the industry in that the disease could spread. Analysis of grow out data from 1991 to 2002 in this farm was carried out in order to characterize the disease and the environmental conditions in relation to mortality. Results of farm DF were compared to data from farms not affected by the disease (called farms HC). The “Summer syndrome” occurs during the warm season which is characterized by an increase in water temperature and sunny duration. This disease is characterized by simultaneously highest densities and weakest drying duration between crops in the farms studied. Between 1991 and 2002, the increase of feed input and nitrogen rate in feed has led to a significant increase of the growth rate over the years in farm DF. At the same time, water management has not changed and has induced an increase in environmental waste production. In consequence, an early eutrophication of water is observed, which is concomitant with the beginning of the mortality outbreaks. This could play a role by inducing directly or indirectly a stress for shrimp and/or a growth and/or virulence factors of the pathogen.