红螯螯虾胚胎发育过程中的生化成分变化

采用生物化学方法对红螯螯虾胚胎发育过程中主要生化成分(糖类、蛋白质及氨基酸、脂类及脂肪酸)进行了测定和分析,以期了解胚胎形态发生与营养需求的关系.结果显示:红螯螯虾胚胎发育过程中糖类总体含量很低.总蛋白与总氨基酸(TAA)的含量在胚胎发育过程中均呈下降趋势.在必需氨基酸(EAA)中亮氨酸(Leu)和精氨酸(Arg)的含量较高,而在非必需氨基酸中谷氨酸(Glu)和天冬氨酸(Asp)的含量较高.总脂在胚胎发育过程中的含量总体呈下降趋势,其中性脂和磷脂的主要脂肪酸均为C16:0、C18:0 、C18:1ω9和C18:3ω3.研究认为:在红螯螯虾胚胎发育过程中,糖类主要参与多种特异复合物的合成以及甲壳构建,这些特异复合物在细胞分化中起着重要的信号传递作用.蛋白质和脂类都是红螯螯虾胚胎发育过程中主要的结构和能源物质,蛋白质主要在早期被利用而脂类主要在晚期起作用.饱和脂肪酸(SFA)和单不饱和脂肪酸(MUFA)(C16:0,C18:0,C16:1ω7 和 C18:1ω9)主要作为能源物质被消耗而高不饱和脂肪酸(PUFA)(20:5ω3和22:6ω3)在胚胎发育过程中对于构建细胞膜以及调节中枢神经系统的发育起重要作用.     

日本沼虾胚胎发育不同阶段主要生化成分的变化

为了解甲壳动物胚胎发育过程中主要营养物质消耗利用的规律，采用生物化学方法测定了日本沼虾胚胎发育过程中7个发育期的主要生化成分。结果表明，在日本沼虾胚胎发育过程中，水分含量在早期无显著变化．发育至溞状幼体期达到最高。蛋白质含量在早期略有升高，而从后无节幼体晚期开始下降。脂类含量则逐期下降，只是在前溞状幼体期有所升高。这表明在胚胎发育过程中，脂类和蛋白质不仅在构建组织器官过程中起到重要作用，且两者可能分别作为胚胎发育不同时期的主要能量来源。脂肪酸变化研究表明：DHA主要参与细胞和亚细胞结构形成。亚油酸和亚麻酸的含量在胚胎发育过程中下降，可能为胚胎发育提供能量，并合成部分DHA。∑ω-3HUFA在前溞状幼体期含量开始增加，主要用于胚胎发育后期细胞结构的形成。棕榈油酸在溞状幼体期含量骤然下降，主要作为能量物质被消耗。日本沼虾胚胎发育不同阶段主要生化成分的变化与其组织、器官的发育关系密切。     

红螯螯虾人工繁殖试验

亲虾抱卵率８７５％,孵化率９０％,９８尾抱卵虾共育出１７８００尾２－３ＣＭ幼虾,平均每尾抱卵虾育苗１８２尾。     

不同脂肪源对红螯光壳螯虾幼虾生长、消化酶活性及其肌肉生化组成的影响

通过在人工配合饲料中分别添加5%的花生油、猪油、鱼油和豆油作为主要脂肪源,以商业饲料为对照,进行8周饲喂实验,研究不同脂肪源对红螯光壳螯虾(Cherax quadricarinatus)幼虾生长、消化酶活性及其肌肉生化组成的影响。结果显示,不同脂肪源对红螯光壳螯虾幼虾的体长增长率和特定增长率影响不显著(P0.05);但增重率各组间存在显著性差异(P0.05),以豆油组最高,达到2332.93%,花生油组最低,为1839.50%;豆油组肝胰腺指数显著高于其他各组(P0.05),为0.75%。幼虾存活率以豆油组最高(P0.05),达到83.3%,鱼油组较低,仅为56.7%。不同脂肪源饲喂组的肝胰腺胃蛋白酶活力无显著差异(P0.05);脂肪酶活力花生油组显著高于其他实验组(P0.05),为1177.23U/g(prot);淀粉酶活力各组间差异显著(P0.05),由高到低依次为鱼油组、对照组、豆油组、猪油组、花生油组;纤维素酶活力以花生油组较高,为61.14U/(gprot()P0.05)。幼虾腹部肌肉中各种脂肪酸的含量明显受到饲料中脂肪酸种类和含量的影响,饱和脂肪酸含量猪油组显著高于其他组(P0.05);单不饱和脂肪酸以花生油组含量最高,豆油组最低;多不饱和脂肪酸则以豆油组含量最高(P0.05)。在各实验组中,豆油组红螯光壳螯虾幼体具有最高的体质量增长率和存活率,较高的肝胰腺指数和肝胰腺消化酶活力,豆油组幼虾腹部肌肉中多不饱和脂肪酸尤其是亚油酸和亚麻酸含量也较高。因此,以豆油作为主要脂肪源能够满足红螯光壳螯虾幼体的生长需要,获得较好的饲养效果,并降低饲料成本。     

池塘养殖红螯螯虾试验

红螫螫虾（Ｃｈｅｒａｓｑｌｌａ’Ｉｌｌｃｎｄｌｌｔｌｌｌｌｓ）,原产于澳大利亚北部。在分类上属甲壳纲、十足国、长臂虾科、光壳虾属。因外形酷似海中龙虾,所以又称澳洲淡水龙虾。自八十年代起,澳大利亚对红螫螫虾进行商业开发养殖,由于其自身优点,在澳洲和美国掀起一股养殖和消费热潮。日本、法国、西班牙和东南亚许多国家先后从澳洲引种试养,并显示出很大的发展潜力。我国１９９２年开始引进,在全国多个地方试养。但目前报道,大多集中在澳洲淡水的生物学特性方面,关于池塘养殖试验至今还不多见。作者于１９９８年５月５日至…     

克氏原螯虾胚胎发育的形态学变化

采用实验室内小规模实验的方法，在水温（26±1）℃的条件下，对克氏原螯虾（Procambarus clarke）胚胎发育过程中的形态学变化和发育时间进行了系统地研究。实验结果表明，克氏原螯虾的胚胎发育过程可以分为9个主要阶段：受精卵、卵裂期、囊胚期、原肠期、前无节幼体期、后无节幼体期、复眼色素期、预备孵化期和孵化期；胚胎发育早期卵径无显著变化，保持在2mm水平，仅在预备孵化期卵径开始显著增大；发育过程中胚胎的颜色逐渐加深，表现为橄榄绿色一灰绿色-灰褐色-棕褐色-红褐色-暗红色的变化趋势；水温26℃的条件下，整个胚胎发育过程需15d左右；刚孵化出的幼体在形态结构上与成体相类似。     

红螯螯虾育苗中的敌害及防治方法

红螯螯虾育苗过程中,由于敌害生物的袭击,常使育苗成活率降低、出苗量减少。因此,清除敌害生物,对提高育苗成活率及出苗量是极其重要的。     

红螯螯虾养成技术

1池塘条件选择进排水方便的5号、6号、7号地增,池底平坦．坡比1：2．5以上;虾苗放养前一星期干塘、因晒,两天后用漂白粉于法清塘,翌日往人新水,水深80厘米,不施基肥;同时栽种轮叶黑藻,投放用于鲤鱼繁殖的旧同片．供虾栖息、德联和遮荫用。饲养中后期池塘水深保持在1．2米,投放虾苗后及时用塑料薄膜沿场四周围成防选墙。2苗种来浑与放养虾苗分两次引进,5号池放养的虾苗子5月27日引进,软壳虾们多,体质差,运输过程中虾苗死伤多．暂养后过数放入池塘．体长2～4厘米。6号地、7号地放养的虾苗6月3日引入,运输过程中几乎没有损失,体…     

红螯螯虾的越冬试验

红螯螯虾成虾和幼虾是否能在福建闽南地区自然越冬,是评价其在该地区是否有发展养殖生产前景的重要因素之一,为此,我们于1993年10月至1995年3月分别在厦门高崎养鳗场和厦门湖里区湖边水库养殖场进行了成虾和幼虾的越冬试验,现报告如下。1 试验情况和结果 试验分别于1993年10月25日至1994年5月24日和1994年9月15日至1995年3月24日进行。试验池共5只(表1)。红螯螯虾成虾及幼     

不同生长时期红螯螯虾肌肉和肝胰腺内氨基酸和脂肪酸变化分析

为了研究不同生长时期红螯螯虾(Cherax quadricarinatus)肌肉和肝胰腺内脂肪酸和氨基酸的动态变化,选取90 d (第二性征未发育)、140 d (第二性征发育成熟)和180 d (性腺发育成熟)的红螯螯虾,分别测定其肌肉和肝胰腺内氨基酸和脂肪酸的含量。结果显示,90 d红螯螯虾肌肉中的必需氨基酸总量显著高于其他2个时期(P<0.05);而红螯螯虾肝胰腺内必需氨基酸总量和非必需氨基酸总量均随着日龄增加而逐渐下降。比较不同生长时期肌肉中脂肪酸含量发现,随着日龄增长,饱和脂肪酸(SFA)含量呈下降趋势;而单不饱和脂肪酸(MUFA)含量呈先上升后下降的变化趋势,140 d含量最高[(25.69±0.42)%];多不饱和脂肪酸(PUFA)含量呈上升的变化趋势。肝胰腺中SFA含量在 3个生长时期内无显著性差异(P>0.05),MUFA含量呈先上升后下降的变化趋势,140 d含量最高[(37.44±0.59)%],而PUFA含量变化与MUFA正好相反。营养价值评估结果显示,180 d (可上市销售)的红螯螯虾肌肉内必需氨基酸指数(49.96%)高于联合国粮农组织/世界卫生组织(FAO/WHO)评分模式(31.50%)和全鸡蛋蛋白质模式(43.10%),是较为理想的优质食物蛋白源。由上可知,在不同生长时期,肌肉和肝胰腺中的氨基酸、脂肪酸的主要消耗不同,研究结果对了解不同生长时期红螯螯虾营养需求、开发红螯螯虾配合饲料提供了参考依据。     

Biochemical changes during vitellogenesis in the red claw crayfish,Cherax quadricarinatus (von Martens)

Redclaw crayfish (Cherax quadricarinatus) females at different stages of vitellogenesis were sampled to investigate variations in soluble protein, lipid and water content and in the amino acid and fatty acid composition of the hepatopancreas and ovaries. During vitellogenesis, the changes in the content of soluble proteins and lipids in the hepatopancreas and ovaries were dependent on both diet and the reserves from the hepatopancreas. However, in comparison to the ovary, the fluctuation of the amino acid composition in the hepatopancreas suggested that the protein resources mobilized from this organ was compensating for those gained from feeding. Changes in the fatty acid composition of the hepatopancreas showed limited compensatory function as for the quick accumulation of lipids in the ovaries. The proportional amounts of saturated fatty acids/mono‐unsaturated fatty acids/poly‐unsaturated fatty acids (PUFA) and the predominant fatty acids in both tissues indicated that the mobilization and utilization of fatty acids in freshwater species are different from that in marine species. Based on the redclaw's feeding habits, the commercial pellets used in this study may not be optimal, and a diet with less PUFA may suffice for its vitellogenesis and reduce the feeding costs.     

Effect of different dietary protein and lipid levels on growth and survival of juvenile Australian redclaw crayfish, Cherax quadricarinatus (von Martens)

This study determined the effect of different dietary protein and lipid levels on growth and survival of juvenile redclaw Cherax quadricarinatus. Nine practical test diets were formulated to contain three crude protein (CP) levels [260, 310 and 360 g kg^?1, equivalent to 225, 260 and 296 g kg^?1 digestible protein (DP) respectively] at three crude lipid (CL) levels (40, 80 and 120 g kg^?1, equivalent to 38, 67 and 103 digestible lipids respectively), with digestible protein : digestible energy (DP : DE) ranging from 14.6 to 22.6 mg protein kJ g^?1. Three replicate groups of 15 crayfish (initial weight mean ± SD, 0.71 ± 0.13 g) per diet treatment were stocked in 40 L tanks, at 28 °C for 60 days. The highest mean weight, specific growth rate and biomass, with values of 7.0 g, 3.67% day^?1, and 370.2 g m^?2, respectively, were achieved by feeding a diet with P : L = 310 : 80 (P < 0.05). The treatments resulted in a survival rate of 80–91%, feed conversion ratio of 1.08–1.61 and protein efficiency ratio of 2.24–3.08. Results indicated that a diet containing 270 g kg^?1 DP (equivalent to 320 g kg^?1 CP), 75 g kg^?1 digestible lipid (DL) with a DP/DE of 18.4 mg protein kJ^?1, and 0.031 g protein per animal per day was optimum for juvenile C. quadricarinatus under the tested experimental conditions.     

Evaluation of practical diets containing different protein levels on gonad development of female redclaw crayfish Cherax quadricarinatus

The effect of five experimental diets with different crude protein content (220, 270, 330, 390 and 450 g kg⁻¹) on gonad development of female Cherax quadricarinatus was tested under laboratory conditions. After 70 days, a significant linear relationship indicated that higher concentrations of protein and carbohydrates in the hepatopancreas were produced as the dietary crude protein increased ( P  < 0.05). There were significant responses of the gonadosomatic index, hepatosomatic index, biochemical composition of the gonad (protein, lipids, carbohydrates and energy) and frequency of secondary vitellogenic oocytes to dietary protein level, as indicated by significant fits of the quadratic equation to the observed experimental data. The optimal response of the criteria parameters corresponded to levels of crude protein in the range 284–355 g kg⁻¹. Overall, 330 g kg⁻¹ crude protein with a protein : energy ratio of 15.6 mg kJ^–1 was considered the most adequate concentration of dietary protein for gonad development and biochemical composition in female redclaw crayfish.     

Effect of dietary protein‐to‐energy ratio on reproduction in female redclaw crayfish Cherax quadricarinatus

The effect of eight diets with different protein‐to‐energy ratios (P–E ratio=10, 11, 14, 16, 18, 20, 22, 24 mg kJ^?1) on reproduction of female redclaw crayfish Cherax quadricarinatus was tested under laboratory conditions. After 75 days, there was a significant effect of the P–E ratio on final weight, spawning females and the number of juveniles per female. Using the broken‐line and quadratic equations, optimal values for the P–E ratio were: 16.0, 17.1 and 16.0 mg kJ^?1. The P–E ratio significantly affected protein and carbohydrate content and energy in the hepatopancreas. The broken‐line model indicated that the respective recommended values of the P–E ratio for these parameters were: 21.8, 16.7 and 18.6 mg kJ^?1. The concentration of carbohydrates and energy in muscle tended to significantly diminish as the P–E ratio increased. From broken‐line regression analysis, the recommended P–E ratio was 16.6 and 20.2 mg kJ^?1 respectively. No significant differences were found in survival, fecundity, vitellin content in eggs, protein and lipid content in muscle and lipids in the hepatopancreas. We concluded that, overall, a P–E ratio of 18±2 mg kJ^?1 is optimal for reproductive activity of female redclaw crayfish.     

Carbohydrate and lipid digestibility of animal and vegetal ingredients and diets for juvenile Australian redclaw crayfish, Cherax quadricarinatus

Carbohydrate and lipid digestibility of three vegetal and four animal ingredients, and diets in which they were included, were evaluated for juvenile Australian redclaw crayfish, Cherax quadricarinatus. The ingredients were: soy paste, textured wheat, sorghum meal, sardine meals (67% and 58% crude protein), squid meal and red crab meal. A basal diet was formulated, and then seven experimental diets were created, including 150 g kg^?1 of each ingredient in the reference diet. Digestibility was measured in vivo, using chromic oxide as marker. A single‐factor, completely randomized experimental design with three replicates per treatment was performed. Mean carbohydrate digestibility of vegetal ingredients and the corresponding diets was better than carbohydrate digestibility of animal ingredients. Sorghum meal had a carbohydrate digestibility over 94%, and the diet in which it was included over 92%. Soy paste and wheat meals also presented excellent carbohydrate digestibility (around 88% for ingredients and over 90% for diets). Mean carbohydrate digestibility of animal ingredients and their corresponding diets were very poor (from 18% to 32%) and this affected the carbohydrate digestibility of diets in which they were included (87–89%). Lipid digestibility was also better for vegetal ingredients. Soy paste and wheat meal recorded values over 93% and their diets over 94%. Sorghum lipid presented slightly lower digestibility. Some of the animal ingredients, especially red crab, had an excellent lipid digestibility (92.1%).     

Carbohydrate and lipid digestibility of animal and vegetal ingredients and diets for the pre-adult redclaw crayfish, Cherax quadricarinatus (von Martens)

In vivo carbohydrate and lipid digestibility of four animal [sardine meals 67% and 58% crude protein (CP), squid meal and red crab meal] and three vegetal (soy paste, textured wheat and sorghum meal) ingredients and diets were evaluated in experimental diets for pre-adult redclaw crayfish, Cherax quadricarinatus . A reference and seven experimental diets were formulated, including 14.5% of each ingredient in the reference diet. A single factor, completely randomized experimental design with five replicates per treatment was done. Experimental organisms were pre-adult redclaw of 10±0.8 g. The best carbohydrate digestibilities were recorded for some vegetal ingredients such as sorghum and textured wheat (93.6% and 83.9%) and the corresponding diets (90.9% and 90.8%). For animal ingredients, carbohydrate digestibilities were very poor (from 12.3% to 41.1%), and the inclusion of these ingredients diminished the digestibility of the corresponding experimental diets as compared with the reference diet (86.3–89.2% vs. 89.9%). The highest lipid digestibility corresponded to red crab meal (97.5%). Textured wheat and soy paste meal also had excellent lipid digestibility (96.4% and 95.1%). The same tendency was found for the corresponding diets. The lowest percentages were obtained with 58% crude protein sardine meal (32.9%) and its diet (86.2%).     

Histopathological survey of diseases and pathogens present in redclaw crayfish, Cherax quadricarinatus (Von Martens), cultured in Ecuador

A histopathological survey of commercial farms in Ecuador culturing redclaw crayfish, Cherax quadricarinatus (Von Martens), revealed the presence of different viral, bacterial and non‐infectious pathologies. A total of 536 animals from 27 different farms were analysed during a 3‐year period; 25, 154 and 357 specimens in 1995, 1996 and 1997, respectively. From the total sampled, a virus referred to as Cherax quadricarinatus bacilliform virus (CqBV) had a prevalence of 44% in animals examined during 1996 and 33% in 1997. A rickettsia‐like organism (RLO) was detected in five specimens sampled from three different farms in 1995. This RLO was detected in 36 and 12% of samples analysed in 1996 and 1997, respectively, and was the infectious agent most frequently associated with mortalities above 60%. Co‐infection by CqBV and the RLO was observed in 18 and 3% of the crayfish examined in 1997 and 1998, respectively. Five specimens out of 25 examined presented no sign of an infectious agent during 1995. The proportion of specimens testing negative by histopathology to known or suspected infectious agents was 25 and 32% in 1996 and 1997, respectively. Although different infectious agents were present in cultured crayfish, farms in general had overall survivals higher than 50% in most ponds. Other conditions observed included an intracellular prokaryotic organism, iron granules in the R and F cells of the hepatopancreas, different species of epibionts on the surface of the gills and body, and two cases of haemocytic enteritis. Two cases of serious mortality in different farms were associated with the presence of Cowdry type A inclusions, pyknosis, karyorrhexis and haemocytic infiltration in the stomach hypodermis and the antennal gland.     

红螯螯虾雄性生殖系统的生化组成及精子代谢

通过对红螯螯虾（Cherax quadricarinatus）雄性生殖系统各组织的生化测定和乳酸脱氢酶（LDH）、琥珀酸脱氢酶（SDH）、延胡索酸还原酶（FR）的活性测定发现，红螯螯虾精荚（含精子）中的糖类和蛋白质含量丰富，分别为18．264和12．846mg／g（FW），总脂含量相对较低，仅为1．613mg／g（FW）；精子（含初级精荚壁）亦以糖类和蛋白质含量较高，分别达到5．227和8．475mg/g（FW），总脂含量因过低而未能测出，但精子的上述物质含量均显著低于精荚。酶活性测定发现，LDH酶活性以精巢、输精管和射精管较高，其中又以前输精管最高，为1426．258U／（g protein），可能与其功能相关；精子和精荚LDH活性极显著低于输精管，含量分别为87．375和36．215U／（g protein），两者间差异显著；FR活性在精荚和精子中较高，两者分别达到19．945和15．732U／（mg protein），显著高于生殖系统其他组织器官，但均未检测到SDH酶活性，故其SDH／FR的比值趋向于0。而生化物质的组织化学以及酶组化定位的结果进一步证实了上述结果。此外，LDH同工酶酶谱结果证实，精荚仅含有一条厌氧型LDHA编码亚基占优势的同工酶谱带。所有实验结果表明，红螯螯虾精子代谢的方式以厌氧型为主，其代谢底物主要为糖类，为厌氧型糖酵解，其代谢底物由次级精荚壁提供。     

Estimating production costs of preadult redclaw crayfish,Cherax quadricarinatus,reared in a commercial nursery system: A stochastic bioeconomic approach

A stochastic bioeconomic model was used to estimate the production cost and risk factors affecting economic performance of juvenile redclaw crayfish, Cherax quadricarinatus, commercial nursery production, in a farm located in Baja California Sur, Mexico. At harvest, the biological submodel showed there is 95% confidence to obtain an average weight of 19.98 g, with 126,341/ha surviving organisms, representing 84% survival. Biomass was 2.5 t/ha, with a feed conversion ratio (FCR) of 0.98, reflecting the efficient adaptation of the species to culture conditions. The economic submodel showed that at Day 90, there is 95% confidence that the cost of producing a preadult will be US$0.090 or US$4.55/kg. With increasing demand and worldwide sale prices of US$9/kg, there is a potential market for 20–30 g redclaw reared in intensive lined ponds. Sensitivity analyses showed that the regression coefficients from a second‐order polynomial used for calculation of FCR associated with time (a₂ and a₁) were the most important parameters influencing the production cost. Mortality rate and parameters used to calculate individual weight also had considerable influence on production cost. The bioeconomic analysis contributes significantly to establishing the economic viability of the intensive three‐phase production system.