克氏原螯虾(Cambarus clarkii)含肉率和营养成份分析

克氏原螯虾(Cambarus clarkii)是一种分布范围较广的淡水虾类,因其壳稍厚、头胸甲较大、螯足粗壮,含肉率较日常食用的其它虾类为低。本文对克氏原螯虾的含肉率和营养成份作了分析,测定结果表明:总含肉率虽不及日本沼虾,但最高也有24.5%;含肉率的高低与个体大小、性成熟程度、以及季节生长等特点有关;肌肉中的氨基酸含量丰富,不亚于食用鳊鱼。对此种虾类的自然资源利用应当予以重视。     

克氏原螯虾无公害养殖技术

正克氏原螯虾属杂食性,在养殖过程中应坚持"荤素搭配,精青结合"的投喂原则,以避免"红壳虾"、"铁壳虾"、"钢壳虾"的出现。克氏原螯虾俗称淡水小龙虾,其肉质丰满,味道鲜美,营养丰富,是名贵的淡水虾类,国内市场消费日益火爆,价格持续攀升,养殖养殖前景一片光明。近年来,随着人们生活水平的不断提高,广     

发酵饲料对克氏原螯虾生长性能、肌肉品质、抗氧化能力和肠道微生物群落的影响

为探究克氏原螯虾配合饲料经发酵处理后的饲喂效果，分别用未发酵和发酵饲料在室内循环水系统中饲养体重为(4.91±0.18) g的克氏原螯虾幼虾8周，采样分析发酵饲料对克氏原螯虾生长、肌肉品质、消化力、抗氧化能力及肠道菌群结构的影响。结果显示，(1)发酵饲料水中溶失率显著低于未发酵饲料；(2)发酵饲料显著提高克氏原螯虾增重率和特定生长率，降低饲料系数，但对存活率、肝体比、含肉率和体成分无显著影响；(3)发酵饲料显著提高克氏原螯虾肌肉硬度、弹性、咀嚼性和胶黏性，降低了黏附性；(4)发酵饲料显著提高克氏原螯虾肝胰腺及肠道中胰蛋白酶和脂肪酶活性，血清和肝胰腺中超氧化物歧化酶、酸性磷酸酶和碱性磷酸酶活性，以及肝胰腺总抗氧化能力；(5)发酵饲料显著提高了肠道绒毛长度和宽度；(6)发酵饲料改善了克氏原螯虾肠道微生物结构，显著升高了厚壁菌门和放线菌门相对丰度，同时提高了肠道菌群多样性。研究表明，饲料经发酵处理后可以有效提高克氏原螯虾生长性能、肌肉品质、消化力和抗氧化能力，改善了肠道组织结构，改变了肠道微生物结构，为克氏原螯虾新型环保饲料的生产提供理论依据。     

克氏原螯虾体征性状与肌肉质量的相关及通径分析

含肉率是克氏原螯虾的重要经济性状之一,与肌肉质量呈正相关。为鉴定与肌肉质量相关的体征性状,收集904尾野生克氏原螯虾(397尾雄性、507尾雌性),并根据体质量分别将雄、雌个体分成10、15、20、25、30、35、40、45 g 8个不同规格的群体。对各规格克氏原螯虾的螯质量、螯长、体质量、体长、肌肉质量(腹部肌肉)、含肉率(肌肉质量占体质量百分比)、头胸甲长与头胸甲宽性状进行测定。统计分析发现,除含肉率外的6个性状数值均随体质量增加而增加。同等规格的雌性个体的体长、肌肉质量与含肉率均极显著大于雄性;相反,雄性个体的螯长与螯质量极显著大于雌性。相关分析结果显示,在中等规格(25～35 g)和大规格(40～45 g)群体中,螯质量与含肉率呈极显著负相关。多元逐步回归分析与通径分析结果显示,螯质量与体质量分别对肌肉质量具有负向和正向直接作用。综上可知,降低螯质量是提高克氏原螯虾含肉率的重要育种策略。     

养殖密度对克氏原螯虾大规格苗种生长和存活的影响

以体重(2.03±O.19)g克氏原螫虾(Procambarus clarkii)大规格苗种为研究对象,研究了26℃下,27、36、45、55、64、73尾/m~2 6种养殖密度下,克氏原螯虾大规格苗种生长及存活情况。实验周期为32 d。结果显示:克氏原螯虾幼虾的体长增长、平均日增重、增重率和存活率都随养殖密度的增大而降低,其中日增重由0.110 6 g下降到0.067 8 g,存活率由100%下降到63%。结果表明,养殖密度的增大不利干克氏原螯虾苗种的生长和存活,养殖密度为45尾/m~2是克氏原螯虾大规格苗种生长的最佳密度。     

克氏原螯虾大水面增养殖技术研究

克氏原螯虾（Proambarus clarkii）隶属节支动物门、甲壳纲、原螯虾属。又名克氏螯虾或小龙虾,其肉味鲜美、营养丰富,深受人们喜爱,是目前大水面虾类增养殖的主要品种。近几年由于市场需求急剧增加,克氏原螯虾天然资源急剧减少,     

采用不同粒径膨化饲料养殖克氏原螯虾投饲策略研究

<正>饲料粒径会直接影响水产动物对营养成分的消化吸收，从而影响生长性能。克氏原螯虾在早期生长阶段生长速度快、个体变化大，只投喂一种粒径的饲料并不能满足克氏原螯虾幼虾快速生长阶段所需的营养。因此，有必要针对克氏原螯虾幼虾生长阶段制定不同粒径饲料的投饲策略。在实际养殖生产和试验研究中，多采用2毫米或3毫米粒径的饲料饲喂克氏原螯虾幼虾。     

克氏原螯虾繁殖生物学的研究

结合实验室研究和室外调查等方法,就比较有争议的有关克氏原螯虾繁殖生物学的一些问题进行了较为详细的研究。认为克氏原螯虾雌雄鉴别最可行的方法是根据二者之间腹肢的不同。雄虾的第1、2对腹肢的基部和中段呈红色,末端变白,而雌虾没有这样的腹肢。克氏原螯虾没有生殖蜕皮的习性,交配之前不一定需要蜕皮。武汉地区克氏原螯虾群体一般每年有2个产卵期,一个为5月左右,一个为9月下旬到10月中旬。雌虾的抱卵量在200~300粒。水温22~25℃时,克氏原螯虾胚胎发育的时间为25~33d。     

克氏原螯虾对盐度适应性试验

对克氏原螯虾仔虾采用6个不同的盐度进行了盐度突变试验,2个试验组的初始盐度为2,探讨克氏原螯虾仔虾对盐度适应性。盐度突变试验结果显示,克氏螯虾仔虾对盐度为10以下具有较强的适应性。渐变试验显示,克氏螯虾仔虾的存活率与盐度调整周期有关,3d为1次的调整周期优于2d调整周期。因此,在低盐度水平开展克氏螯虾盐度驯养是可行的。     

贵州稻田养殖克氏原螯虾肌肉营养成分分析

为分析测定贵州湄潭稻田养殖克氏原螯虾(Procambarus clarkii)的肌肉含肉率及肌肉营养成分,采用重量法、索氏提取法、凯氏定氮法、滴定和比色法分别测定了克氏原螯虾肌肉(鲜样)中水分、灰分、粗脂肪、粗蛋白质和钙、磷的含量,并采用高效液相色谱法测定分析氨基酸种类和含量。实验结果表明:贵州湄潭稻田养殖克氏原螯虾含肉率为18.40%±1.6%;肌肉中(鲜样)水分、灰分、脂肪和蛋白质含量分别为82.07%±0.01%、1.25%±0.01%、2.06%±0.05%、17.80%±0.43%;测得钙的含量为0.53%±0.002%,磷的含量为1.30%±0.022%。肌肉中17种氨基酸(除色氨酸)总量为16.59%;克氏原螯虾肌肉中所含人体所需必需氨基酸为7.21%,占氨基酸总含量的43.47%,四种鲜味氨基酸为2.87%;占氨基酸总含量的17.31%。经与先前国际提出的FAO模式比较,测出的必需氨基酸比例高于其评价标准,所测得第一限制性氨基酸为缬氨酸,第二限制性氨基酸为赖氨酸。     

Growth and survival of Procambarus acutus acutus (Girard, 1852) and P. clarkii (Girard, 1852) in competitive settings

Third‐instar young‐of‐the‐year (YOY) and juvenile Procambarus acutus acutus and P. clarkii stocked in aquaria, rice forage microcosms and a culture pond were evaluated in intraspecific‐ and interspecific‐competitive settings. Procambarus acutus acutus YOY, which were larger than P. clarkii YOY at stocking, grew and survived at significantly greater rates over fall‐, winter‐ and spring‐temperature courses in aquaria. Juvenile P. a. acutus starting an aquarium experiment with a mean total length (TL) size advantage survived at a significantly greater rate than P. clarkii juveniles. Growth rate of similar‐sized stocked P. a. acutus juvenile was significantly faster than that of P. clarkii juveniles in the same microcosms. Survival of juvenile P. clarkii in the microcosms with P. a. acutus was significantly less than when stocked alone. Estimated survival of 2200 P. a. acutus and 2200 P. clarkii YOY in a culture pond over a 174‐day grow‐out period was 84% and 57% respectively. Growth rate of these YOY P. a. acutus and P. clarkii was 0.48 and 0.40 mm TL day^?1. The body‐size advantage at hatching and through the faster growth of P. a. acutus was important in defining competitive interaction with P. clarkii.     

Effects of Harvest Period on the Production of White River Crayfish,Procambarus acutus acutus

Abstract

Crayfish harvest was initiated at a cool water temperature (15°C) and warm water temperature (20°C) from culture ponds (0.1 ha) with a resident population of white river crayfish, Procambarus acutus acutus.Crayfish were harvested for 24 days for a total of 1,977 trap-days/ha (March 9-May 12, 2000 from the cool-harvest treatment and May 5-June 15, 2000 from the warm-harvest treatment). The mean total length (TL) and production of harvested white river crayfish (WRC) was similar between treatments. The population structures of WRC from the cool and warm periods of harvest were substantially different; large WRC (≤100 mm TL) from the cool-harvest period were 3.1 times more abundant than large WRC during the warm-harvest period. A similar number of small WRC were harvested from the two treatments; however, those small WRC harvested during the warm period was significantly longer than the small WRC during the cool-harvest period. The estimated large WRC biomass contribution to the total harvest from the cool-harvest period was 37% in comparison to 15% during the warm-harvest period. The estimated dollar value of the production during the cool-harvest period was 40% more than that from the warm-harvest period.     

Effects of Pond Renovation on White River Crayfish,Procambarus acutus acutus Production

Abstract

The effects of renovation on the production of white river crayfish, Procambarus acutus acutus were evaluated in ten 0.1-ha earthen ponds. The bottoms and levees of five ponds were reshaped with heavy equipment prior to planting sorghum-Sudan grass forage during the de-watered phase of the culture cycle. Five non-renovated ponds served as a control. The mean total length (TL) of the crayfish harvested from renovated ponds was significantly larger than those crayfish harvested from non-renovated ponds. The renovated pond harvest contained an estimated 43.2% carryover crayfish (>95 mm TL) in comparison to 7.6% in the harvest from non-renovated ponds. By weight, carryover crayfish constituted an estimated 69.3% of the harvest from renovated ponds, compared to 21.0% from non-renovated ponds. No difference was observed in the harvest between treatments; however, the low proportion of young-of-the-year crayfish in the renovated pond harvest may adversely impact future production.     

小龙虾不同部位的无机砷含量分析比较

在6mol/L盐酸水浴条件下,无机砷以氯化物形式被提取,实现无机砷和有机砷的分离,用氢化物发生原子荧光光谱法测定小龙虾不同部位的无机砷含量,检出限为0.05mg/kg,回收率在93.3%～105.2%之间,RSD<5%。检测结果表明,小龙虾无机砷含量具有明显的部位差异,内脏与鳃的含量远高于肌肉中的含量。     

Low genetic variability of the white‐clawed crayfish in the Iberian Peninsula: its origin and management implications

• 1. A study on the genetic variability of the white‐clawed crayfish was carried out based on mitochondrial cytochrome oxidase subunit I gene sequences. The sequences applied were more informative regarding white‐clawed crayfish genetic variability than others previously used.
• 2. Two haplotypes were found to exist in the Iberian Peninsula. The haplotypes exhibit a strong geographic subdivision (Φ_ST=0.83). One of the Iberian haplotype s was similar to north Italian haplotypes and the second differed in only one mutation. This pattern of genetic variability contrasts with those found in glacial refugial areas of France, Italy and the Balkan Peninsula.
• 3. Two hypotheses on the origin of the white‐clawed crayfish in the Iberian Peninsula are discussed: (i) one based on an anthropogenic origin, and (ii) a second based on a successive number of postglacial ancient and recent bottlenecks, i.e. the disjunction between Iberian and Italian populations of white‐clawed crayfish species is due to competition between A. italicus and A. pallipes, in addition to the impact of crayfish plague and human translocations.
• 4. New references for the white‐clawed crayfish in the Iberian Peninsula were found in medieval and Arabic texts. The results show that this species has been thriving in this peninsula since ancient periods and that its indigenous status should not be questioned.
• 5. Conservation action and plans should consider the low genetic diversity as a limitation for farm‐raising specimens more adapted and resistant to changing environments and diseases.

Copyright © 2007 John Wiley & Sons, Ltd.     

CHANGES IN CRAWFISH PRODUCTION COSTS AND CURRENT PRODUCTION PRACTICES USED

Louisiana State University Agricultural Center cost estimates for single-crop crawfish production costs are analyzed for the period, 1991–2010, to determine changes in the cost components of Louisiana crawfish production. Fuel costs have contributed the most and fixed expenses the least to increased production costs, with total expenses per acre increasing by an average of 3.8% per year if land is not included and by 3.6% per year if land is included. Crawfish prices have varied greatly over the period, ranging from $0.50/lb in 1993 to $1.75/lb in 2000. Production practices used by Louisiana crawfish producers are highly variable, creating challenges for estimating representative production cost estimates.     

Ontogenetic changes in digestive proteases and carbohydrases from the Australian freshwater crayfish, redclaw Cherax quadricarinatus (Crustacea, Decapoda, Parastacidae)

Juvenile redclaw crayfish, Cherax quadricarinatus, show non‐selective feeding behaviour when commencing feeding, but change to a dietary preference for plant material as they grow. This study aimed to find any ontogenic changes in digestive enzymes that might be associated with the change of diet. The enzymes in the digestive tract initially showed high levels of proteases and low levels of carbohydrases, but as the crayfish grew, the levels of proteases fell and the levels of the carbohydrases generally rose, in parallel with the increased preference for plant food. Cellulase was present in all free‐living stages. Dietary requirements of juvenile redclaw are probably quite similar to those of larger specimens.     

Time‐series analysis of native and non‐native crayfish dynamics in the Thames River Basin (south‐eastern England)

相似文献