Effect of dietary protein level on the growth and survival of pre-adult freshwater crayfish Cherax quadricarinatus (von Martens) in monosex culture

Feeding trials with five levels of crude protein (CP) (22%, 27%, 33%, 39%, and 45%) and digestible energy ranging from 14.32 to 15.21 kJ g^?1 were carried out to determine optimum dietary protein for the growth and production of pre‐adult freshwater crayfish Cherax quadricarinatus. Triplicate groups of males (ω=23.1±0.58 g) and females (ω=21.8±0.33 g) were fed diets for 70 days in monosex culture. Optimal digestible protein (DP) was estimated for males by fitting mean weight gain to a quadratic model (y=27.86+0.839x–0.0216x², r²=0.945), and a linear model for females (y=32.84–0.0745x, r²=0.959). Optimal male growth occurred with 25.6% CP, equivalent to 19.4% DP. Male crayfish attained significantly higher final weights and absolute growth rate than females fed the 22%, 27%, and 33% CP diets. The results indicated that a 19.4% DP diet, with a P/E ratio of 11.4 mg kJ^?1, produces an optimum growth response for pre‐adult C. quadricarinatus under experimental conditions.     

红螯螯虾的室内人工育苗

于1996-1998年,在浙北地区,对澳大利亚引进的红螯螯是进行亲虾培育、人工越冬,怀卵孵化,室内人工育苗技术的研究。研究表明,在浙北地区,2.8-4.9g的幼虾经5个月左右的饲养可以达到性成熟并部分怀卵,利用电厂余热水水泥池人工越冬的成活率可达70%以上。越冬后亲是在水温20℃以上即开始交配怀卵,怀卵盛期4-6月。红螯螯虾一年可产卵4次,但只有第一、二次怀卵可用于育苗生产,个体一次怀卵量较少,一般为400-500粒,但群体怀卵比率较高。试验还表明,红螯螯虾出膜幼体即呈幼虾状,需依附母体7-10d后才营独立生活并开口摄食外源性饵料,所研制的幼虾Ⅰ号饲料为红螯螯虾室内人工育苗较好的开口饲料。室内人工育苗成活率可达60%以上。     

Effect of dietary protein level on growth and survival of juvenile freshwater crayfish Cherax quadricarinatus (Decapoda: Parastacidae)

Protein requirements of juvenile freshwater crayfish Cherax quadricarinatus, with initial mean weight of 1.08 ± 0.34 g, were studied. Juveniles were fed experimental diets containing seven levels of crude protein (CP) (20, 25, 31, 37, 43, 49, and 55%) and 18.73–21.45 kJ  g^?1 of gross energy. The highest mean weight and specific growth rate (SGR) (P < 0.05), with values of 9.6 g, and 3.64% day^?1, respectively, were achieved by feeding a diet of 31% CP. This diet resulted in a survival rate of 80% over 60 days of culture at 27 °C. The higher protein level tested (55% CP), yielded a significantly (P < 0.05) lower mean weight of 6.4 g. However, there were no significant differences in SGR among the 20, 25, and 49% CP diets. Feed Conversion Ratio (FCR) was close to 1 for all treatments except the lowest (20%) and highest (55%) CP. Optimum protein requirements were estimated by fitting mean weight gain data to a quadratic model (y = 1.142+0.484 ? 0.0071x², r² = 0.952, P < 0.05). Optimal growth occurred with 34.2% CP, but the results suggest that optimum protein level for 1‐g juvenile C. quadricarinatus is 31% in least‐cost diets. The information obtained will contribute to the formulation of diets that will enhance production of C. quadricarinatus.     

Digestive enzyme response to supplemental ingredients in practical diets for juvenile freshwater crayfish Cherax quadricarinatus

A feeding trial was conducted to determine digestive enzyme activity in Cherax quadricarinatus in response to diet composition. Eight experimental diets, each containing one of squid, red crab, sardine (600 and 650 g kg^?1 crude protein), sorghum, wheat meal, soy paste and the reference diet were evaluated over 30 days in terms of amylase, lipase, and protease activities in the hepatopancreas. The diet containing wheat meal produced the highest amylase activity. Lipase activity was not significantly different among treatments. Protease activity was higher in animals fed fish meal (60 g kg^?1 protein), soy paste and reference diet. Results suggest that C. quadricarinatus can modify hepatopancreatic enzyme levels in response to different compounds in the diet and can digest a broad variety of ingredients, particularly starch.     

澳大利亚红螯螯虾体表切头虫(Diceratocephalasp.)的初步研究

对共生于澳大利亚红螯螯虾体表的切头虫的生活史和致病性进行了研究,结果表明,２５℃时,虫卵经过２５￣３０ｄ孵化,再经过７０￣８５ｄ的生长达到性成熟并产卵。成虫通常固着在红螯螯虾触角和步足的基部、腹部的腹面边缘、额剑、口器等部位,不破坏虾卵。成虫、幼虫和虫卵均不存在于螯虾的鳃和鳃腔。     

红螯螯虾生物学特性的观察及与克氏螯虾的比较

本文描述了红螯螯虾的生物学特性,如分类地位、外形结构、栖息习性、消化器官与食性、呼吸器官及溶氧需求、蜕壳与生长、繁殖等,并与克氏螯虾进行了比较。     

不同光周期下红螯螯虾幼虾摄食节律的研究

在不同光周期下对红螯螫虾(Cherax quadricarinatus)幼虾的摄食节律进行了研究.结果显示:红螯螯虾具有明显的日摄食节律,24L(持续光照)、12 L∶12D(12h光照:12h黑暗)和24D(持续黑暗)光周期下,其摄食率、摄食量和摄食发生率均在19:00 - 21:00和5:00 -7:00出现峰值,分别为:13.01％和15.58％、20.82％和14.75％、12.77％和16.89％,属晨昏型摄食.光周期和不同时段对红鳌幼虾摄食无显著的交互作用(P＞0.05).     

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.     

红螯螯虾感染白斑综合征病毒

红螯螯虾(Cherax quadricarinatus)是澳州淡水龙虾的一种,属甲壳纲、十足目、长尾亚目、拟螯虾科、光壳虾属,原产地澳大利亚,具有个体大、生长快、食性杂、易饲养等养殖性能优势;同时,因其肉味鲜美、富含低胆固醇蛋白质,是目前世界上较名贵的淡水经济虾之一。目前,美国、拉丁美     

红螯螯虾血细胞分类、结构与免疫特性研究

血细胞在甲壳动物免疫过程中起重要作用,探讨红螯螯虾(Cherax quadricarinatus)不同类型血细胞结构与免疫特性有助于其病害防治。应用流式细胞术(FCM),根据前向角散射光(FSC)和侧向角散射光(SSC)的强度差异对血细胞进行分类,利用特异性荧光染料进行标记,分析血细胞总数(THC)、线粒体数量、溶酶体数量、吞噬活力、活性氧(ROS)含量、一氧化氮(NO)含量和非特异性酯酶活力。结果显示,应用FCM可以区分透明细胞(HC)、半颗粒细胞(SGC)和颗粒细胞(GC)三类血细胞,其占比分别为9.82%、61.11%和25.24%;红螯螯虾平均血细胞总数(THC)为(8.43±0.87)×10~6个/mL;GC含有最多数量的线粒体和溶酶体,HC中含量最少;HC、SGC和GC的吞噬率分别为2.54%、14.45%和6.98%,SGC吞噬活力最强,HC最弱;HC、SGC和GC的活性氧(ROS)含量分别为7.80、45.95和134.69 AU,GC的ROS含量最高,HC最低;HC、SGC和GC的一氧化氮(NO)含量分别为8.20、79.78和344.31 AU,GC的NO含量最高,HC最低;HC、SGC和GC的非特异性酯酶活力分别为86.59、121.84和236.91AU,GC的酯酶活力最高,HC最低。研究表明,红螯螯虾三类血细胞在形态结构、数量及免疫特性上均存在差异,SGC的数量最多、吞噬活力最强,而GC含有最多与能量供应、免疫防御相关的细胞器,并拥有最强的氧化活力和酯酶活力,表明GC和SGC是红螯螯虾免疫防御过程中发挥主要作用的血细胞类型。     

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.     

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.     

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.     

澳大利亚红螯螯虾对水中氨氮浓度耐受性的研究

澳大利亚螯螯虾氨氮急性中毒试验的结果表明,在水温２１－２２℃,ｐＨ６．７－７．２时,该虾对水中氨氮浓度的耐受性为：４８小时的ＬＣ５０为１１８．０６ｍｇ／Ｌ,而且ＬＣ５０值随试验时间的延长而降低。     

红螯光壳螯虾(Cherax quadricarinatus)酚氧化酶原基因的克隆与表达分析

为深入了解红螯光壳螯虾酚氧化酶原(proPO)基因的非特异性免疫机制,利用RACE技术从红螯光壳螯虾血细胞中克隆到酚氧化酶原基因cqproPO,cqproPO基因cDNA全长为2 962 bp,开放阅读框为1 998 bp,编码665个氨基酸,其结构中含有两个铜离子结合位点,预测分子量为75.86 ku;同源性比对结果显示,红螯光壳螯虾CqproPO与克氏原螯虾酚氧化酶原的同源性最高为79％,其次是淡水螯虾74％、挪威龙虾69％、美国龙虾67％等;进化分析发现CqproPO与克氏原鳌虾、淡水螯虾、挪威龙虾、美国龙虾等的酚氧化酶原亲缘关系最近;Realtime-PCR实验结果表明,CqproPO在血细胞中表达水平最高,其次是肠、触角腺、鳃等;在肝胰腺中有适量表达;WSSV感染后红螯光壳螯虾CqproPO mRNA在血细胞、肝胰腺和鳃组织中具有不同的时空表达趋势,但感染组和免疫后感染组mRNA表达量分别在感染后12h和24 h达到最大值,且在3种组织中2个感染组的CqproPO表达量为对照组的1.3 ～2.55倍,显著高于对照组(P＜0.05),之后cqproPO基因的转录水平明显下降.免疫后再受病毒感染的虾,CqproPO mRNA的表达量在3种组织中总体高于感染组,感染7d后的免疫保护率达到51.86％,表明免疫增强剂可使机体的抗病毒能力增强,对防御WSSV感染具有一定的免疫保护作用.     

亚硝酸盐对红螯光壳螯虾不同组织免疫相关酶活性及超微结构的影响

应用透射电镜技术,结合生物酶测定,研究了水体中不同浓度亚硝酸盐胁迫下红螯光壳螯虾肝胰腺、鳃和肌肉组织中免疫相关酶的活性变化,以及对肝胰腺和鳃的形态学影响。结果显示,与对照组相比,亚硝酸盐胁迫下,3种组织的ACP、AKP、SOD以及GSH-PX的活性都显著降低(P<0.05);随着亚硝酸盐浓度增加,酶活力呈现降低的趋势;鳃组织Na+,K+-ATPase和Ca2+,Mg2+-ATPase的活性也显示出随亚硝酸盐浓度升高而降低的趋势。超微结构显示,随着亚硝酸盐浓度增加,鳃角质层受损、断裂;上皮细胞排列疏松、空泡化;细胞器变形;鳃腔内也出现空泡化现象,血细胞变形。肝胰腺上皮细胞排列杂乱无章,细胞裂解,空泡化;微绒毛受损、断裂,肝小管间距扩大、结缔组织变得稀薄,血细胞变形;高浓度组R细胞的脂滴减少,核膜解体,细胞膜破裂,空泡化加剧;F细胞的核糖体减少,空泡化加剧,内质网水肿。研究说明亚硝酸盐对红螯光壳螯虾3种组织的免疫相关酶活产生影响,并损伤肝胰腺和鳃的形态学结构,影响其生物学功能。     

Growth of redclaw crayfish Cherax quadricarinatus (Von Martens 1868) (Decapoda: Parastacidae) juveniles fed isoproteic diets with partial or total substitution of fish meal by soya bean meal: preliminary study

Growth of juvenile redclaw Cherax quadricarinatus fed 400 g kg^?1 crude protein isoproteic diets substituting fish meal with soya bean meal at various levels (250, 500, 750 and 1000 g kg^?1) was evaluated under laboratory conditions. Juvenile crayfish were reared individually in 1‐L plastic containers for 56 days. Total survival was recorded for all treatments at the end of the experiment. There were no significant differences (P > 0.05) for the specific growth rate among the treatments, although the animals fed with the control diet (100% fish meal) obtained the highest mean daily weight gain (0.055 g day^?1), individual final weight (4.12 g), molts per individual (0.04 molts day^?1) and molting frequency (23.57 days) values at the end of the experiment. Dietary inclusion of soya bean meal at the tested levels hampered the C. quadricarinatus juvenile growth.     

闽西北山区红螯螯虾池塘健康养殖试验

2010年在闽西北山区进行红螯螯虾池塘健康养殖生产试验,经过5个月的养殖,结果8口池塘共产红螯螯虾19095kg,平均单产达0.57kg/m2,养殖成活率64.2%,饲料系数1.31,投入产出比1∶1.69。试验结果表明,池塘养殖红螯螯虾前景广阔。