Apparent digestibility of selected ingredients in diets for white shrimp Penaeus setiferus L.     

J. F. Brunson  R. P. Romaire  & R. C. Reigh 《Aquaculture Nutrition》1997,3(1):9-16

A study was conducted to determine apparent digestibility coefficients for dry matter (ADMD), crude protein (ACPD) and gross energy (AED) of selected ingredients in diets for juvenile Penaeus setiferus . Ingredients tested were corn grain, cottonseed meal, crab meal, grain sorghum, meat and bone meal, menhaden fish meal, rice bran, rice grain, shrimp meal, soybean meal, squid liver powder, wheat flour, wheat gluten, wheat middlings and wheat shorts. ADMD coefficients of test ingredients ranged from 22% to 100% and appeared to be related to the fibre, ash and starch content of the ingredient. ACPD coefficients ranged from 58% to 100%. Plant protein supplements (soybean meal and cottonseed meal) were utilized as efficiently as, or better than, animal protein supplements (squid liver powder, menhaden fish meal, meat and bone meal, shrimp meal and crab meal). ACPD coefficients for meat and bone meal, shrimp meal and crab meal (58–59%) were significantly lower than those for menhaden fish meal (76%) and squid liver powder (82%). AED coefficients (44–100%) varied significantly among plant products of similar proximate composition. Corn grain and wheat flour were better utilized by P. setiferus than other high-starch energy supplements. Wheat gluten exhibited the highest ADMD, ACPD and AED coefficients of all ingredients tested.  相似文献   

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

《Journal Of Applied Aquaculture》2013,25(4):57-66

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.  相似文献   

亚热带水产养殖寒灾预警系统的设计与实现     

涂超 《安徽农业科学》2011,(17):10694-10696

通过对亚热带水产养殖现状的分析，论述了亚热带水产养殖寒灾预警系统建设的必要性、研究的目标和任务，详细介绍了系统的结构和框架，以及亚热带水产养殖寒灾预警的几个关键问题及其解决方法。  相似文献   

Growth overfishing in the brown shrimp fishery of Texas, Louisiana, and adjoining Gulf of Mexico EEZ     

C.W. Caillouet Jr.  R.A. Hart  J.M. Nance 《Fisheries Research》2008,92(2-3):289-302

Growth overfishing in the brown shrimp, Farfantepenaeus aztecus, fishery in inshore (estuarine) and offshore (Gulf of Mexico) territorial waters of Texas and Louisiana, and adjoining waters of the United States’ (U.S.) Exclusive Economic Zone (EEZ), and its potentially detrimental economic consequences to the harvesting sector, have not been among major concerns of Federal and State shrimp management agencies. Three possible reasons include (1) environmentally influenced variations in recruitment that cause wide fluctuations in annual landings, which tend to obscure effects of fishing, (2) competition between inshore and offshore components of the harvesting sector, and (3) partitioning of management jurisdiction among a Federal council and two State agencies. Wide variations in landings led to beliefs that high levels of fishing mortality were tolerable and recruitment overfishing was of no major concern. This encouraged somewhat laissez-faire management approaches that allowed fishing effort to increase over the years.Our objectives were to determine whether growth overfishing occurred in this fishery during 1960–2006, and whether and how decreases in size of shrimp within the landings, in response to increases in fishing effort, affected inflation-adjusted annual (calendar year) ex-vessel value of the landings, i.e., their value to the harvesting sector. Growth overfishing occurred in the early 1990s, and then abated as fishing effort declined due to rising fuel costs and competition from imported shrimp. However, inflation-adjusted annual ex-vessel value of the landings peaked in 1985, prior to growth overfishing.Management actions implemented in 2001 for Texas’ territorial waters, and in the EEZ off Texas and Louisiana in 2006, should limit future fleet expansion and increases in fishing effort, thereby reducing the chances of growth overfishing and its potentially detrimental economic impacts on the harvesting sector. Growth overfishing should be included among the guidelines for future management of this brown shrimp fishery.  相似文献   

桁杆虾拖网捕捞脊腹褐虾网囊网目选择性试验   总被引：3，自引：3，他引：0  

徐宝生  陈雪忠  汤振明  黄洪亮  郁岳峰  张勋  冯春雷 《海洋渔业》2008,30(3)

采用套网试验法在长江口渔场对25 mm桁杆虾拖网网囊网目的选择性进行了试验。结果表明:当网囊网目内径为25 mm时,网囊与套网内脊腹褐虾的体长范围在30~80 mm之间,其中网囊内虾的优势体长在46~70 mm之间,套网内虾的优势体长在41~60 mm之间;50%选择体长L0.5为50.53 mm,选择范围SR为9.86 mm;逃逸虾的平均存活率为96.25%。  相似文献   

硇洲岛周围水域虾拖网虾渔获组成   总被引：1，自引：0，他引：1  

张旭丰  张鹏  谭永光  杨吝 《海洋渔业》2008,30(3)

根据2005年渔业资源监测船生产调查资料和现场取样数据,运用数理统计方法分析了虾拖网虾渔获组成、生物学特征以及月份变化等。结果表明:硇洲岛周围水域虾拖网捕获的虾类主要是沿岸性底栖虾类,渔获中优质虾种少,幼虾比例高,墨吉明对虾、日本囊对虾、哈氏仿对虾是虾拖网渔业的主捕虾种,虾渔获组成存在明显的月份变化。为合理利用虾类资源和促进虾渔业可持续发展,应根据虾类特性开发适宜广东沿海虾拖网的选择性捕捞技术,减少幼虾兼捕量。  相似文献   

Nematopsis marinus n. sp., a new septate gregarine from cultured penaeoid shrimp Litopenaeus vannamei (Boone), in Ecuador     

R Jiménez  L de Barniol  & M Machuca 《Aquaculture Research》2002,33(4):231-240

The septate gregarine Nematopsis marinus n. sp. (Apicomplexa: Cephaline) heavily infected the midgut of cultured Pacific white shrimp Litopenaeus vannamei (Boone) in Ecuador. It is morphologically similar to other species of the genera Nematopsis, but it can be distinguished from them, by having gamonts with a prominent hemispherical protomerite that contained numerous refractile granules and unusual strong gliding movement. There is evidence that shrimp acquired the infection in the ponds, as larval or postlarval stages do not showed infection. Juveniles and adult shrimp had a prevalence and intensity of infection ranging from 50% to 80% and 10 to > 5000 parasites respectively. When voided from the gut, the gregarine keep alive in seawater. This gregarine have been associated with the marine environment and there are no records of this species in low salinity waters or freshwater. Results suggest that N. marinus could have most of the life cycle of the species within the host L. vannamei.  相似文献   

Effect of culture system on the nutrition and growth performance of Pacific white shrimp Litopenaeus vannamei (Boone) fed different diets   总被引：2，自引：0，他引：2  

A.G.J. TACON  J.J. CODY  L.D. CONQUEST  S. DIVAKARAN  I.P. FORSTER  & O.E. DECAMP 《Aquaculture Nutrition》2002,8(2):121-137

Two 8-week feeding trials were conducted with juvenile Pacific white shrimp, Litopenaeus vannamei (Boone) to compare the growth and performance of animals fed a series of experimental and commercial pelleted shrimp and fish feeds and dietary feeding regimes within an indoor running-water culture system and an outdoor zero-water-exchange culture system. The best overall shrimp growth performance was observed for animals fed the experimental shrimp diet and all-day feeding regime under outdoor zero-water-exchange culture conditions. Final body weight and average weekly growth rate under these conditions were 2.8 and 3.4 times greater, respectively, than animals of similar size fed with the same diet under indoor running-water culture conditions. Although direct comparison between indoor and outdoor culture systems is difficult because of the lower indoor water temperatures, and consequently lower mean daily feed intake of animals, it is believed that the higher growth and feed performance of animals reared under outdoor `green-water' culture conditions was primarily due to their ability to obtain additional nutrients from food organisms endogenously produced within the zero-water-exchange culture system. The most promising features of zero-water-exchange culture systems are that they offer increased biosecurity, reduced feed costs and water use for the farmer, and by doing so provide a potential avenue of moving the shrimp culture industry along a path of greater sustainability and environmental compatibility.  相似文献   

猫泛白细胞减少症病毒的分离与鉴定     

夏咸柱  陈跃朋  孙永祥  杨盛华  武银莲  曹福源  李克东  徐成英  吴启华  张建平  凌铭德  殷震 《中国兽医学报》1986,(2)

应用猫肾传代细胞(FK),采用同步接毒的方法,从8份狮、虎、豹病料中分得6株病毒,经与标准病毒作交叉免疫电镜等系统鉴定,证明与猫泛白细胞减少症病毒的特性基本相符,从而首次证实在我国动物园狮、虎、豹等猫科动物中存在猫泛白细胞减少症。  相似文献   

盐度突变对凡纳滨对虾组织碳酸酐酶活性的影响   总被引：4，自引：0，他引：4  

潘爱军  来琦芳  王慧  周凯  么宗利  庄平 《上海水产大学学报》2006,15(1):47-51

采用改进的△pH法检测凡纳滨对虾组织碳酸酐酶活性,监测了环境盐度从5突变到25后对虾鳃和触角腺组织碳酸酐酶活性及其血淋巴渗透浓度的动态变化。结果表明:(1)鳃组织碳酸酐酶活性在盐度突变后4 d内没有显著变化,活性水平在(21.68±1.25)μmol CO2/(mg.min),第5~11天有显著性的增高现象,在第10天活性最高,为(43.03±2.82)μmol CO2/(mg.min),第12天回落至起始水平;(2)触角腺碳酸酐酶活性动态变化的模式与鳃相似,起始增高时间比鳃晚6 d;(3)触角腺碳酸酐酶活性显著增高起始的时间与鳃组织碳酸酐酶活性开始显著下降的时间有关联性;(4)在低盐度时,凡纳滨对虾属于强高渗调变生物。  相似文献