Fecundity, egg development and growth of juvenile crayfish Procambarus (Austrocambarus) llamasi (Villalobos 1955) under laboratory conditions

Procambarus (Austrocambarus) llamasi (Villalobos 1955) is a crayfish endemic to south‐eastern Mexico with aquaculture potential. This study intends to enhance knowledge of the reproductive biology of this species under laboratory conditions, including fecundity, egg development and juvenile growth. Mean fecundity was 311 eggs/female, and egg development occurred in seven stages over a 27‐ to 30‐day time range. The best growth results were obtained at a density of 50 organisms m^?2.Procambarus llamasi is considered to perform well in aquaculture contexts.     

Growth of Juvenile Scup,Stenotomus chrysops,Fed Three Commercial Diets

Juvenile scup, Stenotomus chrysops, 0.5–1.5 g weight were fed three different commercial diets for six weeks to determine growth rates. Diets were hand-distributed to triplicate groups of 30 fish, four times a day. Survival for all treatments was 93%. The diets used were INVE Aquaculture NRD marine diet (NRD), Skretting Feed Products Gemma starter feed (Gemma), and Salt Creek Progression fish starter diet (Progression). While all diets supported good growth, after 6 weeks scup fed the NRD diet were of significantly greater length and weight (P?<?0.05) than fish fed the other diets. The effects of each diet on fish growth were significantly different from each other (P?<?0.05), with final live weight (g), total length (mm), relative growth rate (RGR), and daily weight gain (DWG) measurements higher for fish fed the NRD diet. Scup fed the Gemma diet were of significantly greater length and weight than fish fed the Progression diet. The specific growth rate (SGR) of scup fed either the NRD or Gemma diets were not significantly different; however, both of these diets produced fish with significantly higher SGR than those fed the Progression diet. Feed conversion ratios (FCR) of scup fed either the NRD or the Gemma diets were significantly lower than the FCR of fish fed the Progression diet. SGR values were 6.6%, 6.3%?and 5.6%/day, and FCR values were 1.03, 1.11, and 1.31 for fish fed the NRD, Gemma, and Progression diets, respectively. RGR values were 1,439%, 1,212%, and 895%, and DWG values were 0.33 g, 0.27 g, and 0.20 g/day for scup fed the NRD, Gemma, and Progression diets, respectively.     

隐蔽所对不同生长阶段克氏原螯虾生长的影响

将体质量0.527 g(幼虾)和6.100 g(亚成体虾)的克氏原螯虾饲养在底面积为113 cm^2 、高为12 cm的圆形塑料盒中,一组放入内径为1.9 cm的PVC管作为隐蔽所为隐蔽组,以不放PVC管为对照组,其他条件同隐蔽组,定期测量各组克氏原螯虾的体长、体质量增长量、存活率和蜕壳率等指标,研究隐蔽所对不同规格克氏原螯虾生长的影响。2个月的饲养结果显示,试验第1个月隐蔽组幼虾组体长增长、体长相对增长率、体质量增长及蜕壳量均显著大于对照组( P <0.05),第2个月两组各数据无显著差异( P >0.05);隐蔽组亚成体螯虾摄食量、体质量及蜕壳量均小于对照组。研究结果表明,隐蔽所在螯虾的早期生长阶段对其生长有促进作用,但随着螯虾体格的增大,隐蔽所的促进作用随之减弱,甚至最终抑制螯虾的生长。本研究围绕克氏原螯虾穴居的习性以及趋触性等行为的特点,为生产提供了合理建议。     

盐度对克氏原螯虾幼虾生长的影响

研究了不同盐度对克氏原螯虾幼虾生长的影响.试验于水族箱内进行,试验幼虾的初始体质量(1.82±0.21)g,体长(3.13±0.30)cm.在25 ℃条件下,试验设置0、2、4、6、8、10、12、14计8个盐度梯度,试验结果表明,盐度为0～14时,克氏原螯虾的幼体均能存活与生长.盐度为0～6,成活率较高,生长较快,饵料系数较低,各项指标与对照组差异不显著(P>0.05).当盐度超过此范围时,随着盐度增加,幼虾的成活率下降,生长变慢,饵料系数增大,与对照组差异显著(P<0.05).     

克氏原螯虾对配合饲料感知能力的研究

为了解克氏原螯虾(Procambarus clarkii)对饲料感知的最大空间距离,在稻田养殖环境条件下,利用特定设计的试验设施,研究其对配合饲料的感知能力,以期为合理确定养殖水体投饵点数量和空间布局、增加饲料利用率提供科学依据。结果显示,克氏原螯虾对配合饲料感知的最大间隔距离估算为12 m;在食物间隔距离3 m和6 m捕获的雌虾与雄虾数量无显著性差异(χ²>1.19,df=1,P>0.270),表明雌性与雄性对配合饲料的感知能力没有显著差异。食物感知-搜索时间与食物间隔距离呈正相关,在食物间隔距离为3 m、6 m、9 m、12 m时,食物感知-搜索的最短时间分别为(1.8±0.5) min、(5.0±1.1) min、(11.4±1.7) min、(25.2±2.4) min,最长时间分别为(3.4±0.9) h、(7.3±0.6) h、(9.0±0.8) h、(10.0±1.3) h。当食物间隔距离为3 m和12 m时,受到配合饲料刺激后分别有(68.3±1.6)%和(36.3±1.9)%的克氏原螯虾能在3 h内到达食物源。研究表明,克氏原螯虾对配...     

几种生物饵料对海蜇幼蜇生长的影响

试验结果表明:在海蜇(RhopilemaesculentaKishinouye)养殖过程中,褶皱臂尾轮虫(Bra chionusplicatilis)、细巧华哲水氵蚤(Sinocalnustenellus)、近亲真宽水氵蚤(Eurytemoraaffinis)、蒙古裸腹水氵蚤(Moinamongolica)和卤虫(Artemia)无节幼体,均可作为幼蜇的饵料,在水温22～25℃,pH8 4～8 8,溶氧4～8mg/L,盐度30±0 5的条件下,培养22d幼蜇日生长率为1 2%～3 2%,成活率为100%。其生长率与试验饵料的种类关系不大,而与投喂密度有关。轮虫的合适密度为0 5×104～1 0×104/L。笔者还根据试验结果,以等生物量法,提出了投喂其它几种生物饵料的参考密度指标。以期为海蜇的人工养殖寻找更加广阔的饵料资源。     

不同饵料对瓦氏黄颡鱼稚鱼生长和消化酶活性的影响

将瓦氏黄颡鱼(Pelteobagrus uachelli)稚鱼分为活饵料组(L)、驯化组(D)和饲料组(MP),分别对3个组进行牛长和消化酶活性的监测.结果表明,瓦氏黄颡鱼稚鱼在整个试验期间的特定牛长率,活饵料组>驯化组>饲料组,且3组之间均存在显著性差异(P<0.05).3个组蛋白酶的比活力均随日龄的增加而增加,活饵料组的蛋白酶比活力高于驯化组和饲料组(P<0.05).活饵料组的淀粉酶比活力在试验期间一直处于较低的水平,而驯化组和饲料组的淀粉酶比活力则呈现增加的趋势.活饵料组、驯化组和饲料组的脂肪酶比活力在45日龄以前基本维持在一个特定水平,饲料组的脂肪酶比活力高于驯化组和活饵料组(P<0.05),在45日龄以后,驯化组、饲料组的脂肪酶比活力呈增加的趋势,活饵料组的脂肪酶比活力则呈现降低的趋势.     

不同孵化基质和开口饵料对宽体金线蛭生长发育的影响

比较有机孵化基质对宽体金线蛭卵茧孵化效果和不同开口饵料对苗种生长发育的影响。孵化基质分别为土壤、牛粪有机肥、蘑菇菌渣,开口饵料分别为螺蛳、漂螺。试验结果显示,蘑菇菌渣+土壤组卵茧孵化率高达98.89%,显著高于土壤组和蘑菇菌渣组(P<0.05);幼蛭各生长指标显著高于土壤组、蘑菇菌渣组、有机肥组及有机肥+土壤组(P<0.05);混合组幼蛭各生长指标均显著高于未添加土壤组(P<0.05)。5种不同孵化基质孵化率依次为蘑菇菌渣+土壤>土壤>有机肥+土壤>有机肥>蘑菇菌渣。不同开口饵料的试验比较发现,漂螺组幼蛭成活率为72.50%,显著高于螺蛳组和螺蛳+漂螺组(P<0.05),漂螺组和螺蛳+漂螺组幼蛭体质量显著高于螺蛳组(P<0.05)。生长效果依次为漂螺组>螺蛳+漂螺组>螺蛳组。试验结果表明,蘑菇菌渣可以作为宽体金线蛭卵茧孵化基质;无厣结构的漂螺更适宜作宽体金线蛭幼蛭的开口饵料。     

湖北地区温棚养殖与稻田养殖克氏原螯虾生长特性研究

2018年12月—2019年3月间,定期从温棚养殖和稻田养殖的克氏原螯虾中采集599尾样本,测量克氏原螯虾的体质量(y)、全长(x1)、头胸甲长(x2)、头胸甲宽(x3)、腹节总长(x4)、第一腹节长(x5)、第一腹节宽(x6)、尾节长(x7)、第六腹节长(x8)、第六腹节宽(x9)和螯长(x10),探明温棚养殖幼虾与...     

农（渔）产品品牌的商业价值研究

随着传统农业向现代农业发展,农（渔）产品品牌化的重要性日益突显。消费者的品牌意识在逐渐增强,农（渔）产品的竞争压力也不断增大,市场进入愈加困难。在此背景下,充分认识农（渔）产品品牌的商业价值,从而创建品牌、培育名牌已成为提升农产品市场形象的必然选择,也将成为增加农产品市场竞争能力的主要手段之一。     

Growth of Juvenile Synodontis petricola (Family: Mochokidae) Fed on a Formulated Diet, Artemia or Spirulina and Combinations Thereof

Two age groups of juvenile Synodontis petricola (Group I, 0.5 years and Group II, 1.5 years) were reared on each of five diets: formulated dry diet; Artemia; Spirulina; formulated diet plus Artemia; and formulated diet plus Spirulina. Fish were fed for 84 days and weighed and measured every 14 days. Growth of S. petricola averaged 0.06 mm/day for both age groups. There was no significant difference in percent survival between the fish fed on different diets within each of the two groups but the younger fish (0.5 years) had a significantly lower survival percentage (90.3%) than those in Group II (95.3%). Fish in Group I fed on Spirulina alone grew slower than those fed only on formulated dry feed, whereas the growth rates of fish fed on other diets, or diet combinations, did not differ from each other in both age groups. This revised version was published online in August 2006 with corrections to the Cover Date.     

养殖密度对克氏原螯虾生长及消化酶、免疫酶活性的影响

水温(25±1)℃时,将体质量(3.11±0.10)g的克氏原螯虾幼虾饲养在120 cm×60 cm×20 cm的水族箱中,密度分别为14尾/m2(低密度组)、28尾/m2(中密度组)和42尾/m2(高密度组),研究室内养殖不同密度对生长、摄食、消化酶活性及非特异性免疫的影响.8周的养殖结果显示,克氏原螯虾的存活率随养...     

Sex-Linked Growth Divergence of Summer Flounder from a Commercial Farm

ABSTRACT

In the wild, it is known that adult female summer flounder, Paralichthys dentatus, grow at a faster rate and to a larger body size than males. The age or size at which this divergence in growth rate occurs is not known. At GreatBay Aquafarms, Inc., the sex ratios of three production lots of juvenile fish was examined to determine if females grow faster than males under commercial cultivation and to identify the age and/or size at which sex-linked growth divergence begins. Production lots 99-2, 99-1, and 98-3, ages 8, 12, and 15 months (post-hatch), respectively, were sampled. The gonadal tissue from fish smaller than 60 mm was examined by histology. Fish larger than 12 cm were dissected, and gross observation was used to determine sex. With the exception of two samples that appeared to be males, gonadal tissue from fish under 60 mm appeared undifferentiated. In production 99-2 (8 months) no significant association between the percentage of female fish and body size was found. However, in productions 99-1 (12 months) and 98-3 (15 months) percentage of female fish increased significantly with body size group. At the time of sampling, the average weight of females from lots 99-2, 99-1, and 98-3 was 1.05, 1.1, and 1.4 times heavier, respectively, than males. Results from this study suggest that sex differentiation in summer flounder occurs at 6 to 12 cm, and indicates clear value of all-female production for the commercial cultivation of summer flounder.     

盐度对克氏原螯虾幼虾耗氧率和排氨率的影响

研究了不同盐度对克氏原螯虾幼虾耗氧率和排氨率的影响.试验用虾体长(3.13±0.30) cm,体质量(1.82±0.21) g.25 ℃条件下,试验设置盐度0、2、4、6、8、10、12七个梯度.结果表明,试验范围内,盐度为2时,克氏原螯虾幼虾的耗氧率与排氨率最低,表明幼虾对盐度调节的等渗点约为2.随着盐度升高,幼虾的耗氧率和排氨率上升,Tukey HSD test发现,对照组、2、4、6盐度组的耗氧率、排氨率差异不明显.盐度超过0～6时,幼虾的耗氧率、排氨率影响与对照组相比差异显著.     

亲缘关系对克氏原螯虾仔虾种内斗争的影响

将源于1、2、3、4尾雌虾的克氏原螯虾仔虾以4种方式混养,每个混养群体共有仔虾24尾,设3个重复。结果表明:亲缘关系对幼年螯虾种内斗争影响显著。随着仔虾来源的增多即亲缘关系复杂性的提高,螯虾的存活率总体呈下降趋势,而残虾率、体长变异系数、体长增长率总体上显著上升。     

Shadow area and partitioning influencing mortality,healthiness and growth of juvenile Red Swamp Crayfish Procambarus clarkii (Decapoda)

Crayfish show both shelter‐seeking behaviour and agonistic behaviour. Agonistic interactions among crayfish combatants can be triggered and released by the access of shelter, which is a necessary resource for crayfish. The use of shadow as a shelter has not been thoroughly tested in experiments. In this study, we provided the Red Swamp Crayfish Procambarus clarkii (Girard) with different shadow area and shadow partition to test if shadow can act as a solid shelter. Eleven different treatments designed with different shadow area and partition, and 2640 juvenile crayfish were used. The survival rate increased with the increase of shadow area ratio. The shadow area contributed less to the body weight gain and the number of the survivals without injury. The growth variance of the juveniles under shadow conditions was significantly lower than those maintained without providing shadow. Under the recent experimental settings, generally, more partitioned shadow resulted in lower mortality. With 60% shadow area, more partitioned shadow led to higher body weight gain. The more the partition was provided, the fewer were the injury events, and the lower body weight variance observed. Our experiments indicated that both area and partition of the shadow influenced the growth of juvenile Red Swamp Crayfish.     

不同驯化方式对哲罗鱼仔、稚鱼生长和存活的影响

在水温8．9～14．2℃下,在平列糟（长3m,宽0．4m,高0．2m）中采用A、B和C组三种投喂方式驯养刚开口摄食、体质量0．129±0．07g的哲罗鱼（Huchotaimen）苗60d,以探讨驯化方式对哲罗鱼仔、稚鱼生长、存活和种群变异系数的影响：A组以浮游动物开口,投喂浮游动物3d,投喂水蚯蚓15d后,改投人工饲料;B组以水蚯蚓开121,投喂水蚯蚓15d后,改投人工饲料;C组直接以人工饲料开口。结果表明：C组体质量特定生长率（3．577±0．78％／d）,明显大于A组（3．132±0．87％／d）和B组（3．024±0．91）;A、B、C组的成活率分别为75．67％、74．87％和84．36％,C组明显大于A、B组;A、B和c组鱼体质量变异系数依次为21．47％、22．59％和11．32％,实验表明,直接以人工饲料开口是哲罗鱼规模化养殖中合理的驯化投喂模式。     

凡纳滨幼虾采食不同蛋白水平日粮的免疫与消化率研究

在室内养殖条件下,进行单因素随机设计动物试验,即5种饲料蛋白质水平（31%、35%、39%、43%、47%;以A～E组表示）处理,投喂平均体质量0.2 g的凡纳滨幼虾,养殖60 d。研究结果表明,蛋白质营养对凡纳滨幼虾生长、免疫与抗氧化指标和消化率特征影响显著。随着饲料蛋白水平的升高,特定生长率显著增加,饲料系数下降,E组两项指标最好,分别为5.52和1.96。高蛋白质含量饲料有利于提高对虾免疫指标水平,血淋巴中血细胞浓度、T-AOC活力、POD活力、溶菌酶活力、总蛋白含量,随着蛋白质水平提高显著增加,各项指标E组最高,比A组分别显著提高133.7%、21%、16.8%、20.8%、19.7%(P<0.05);而SOD活力C组最高,与A组差异显著。凡纳滨幼虾对蛋白质的消化率随饲料蛋白质含量增加显著升高(P<0.05),E组比A组提高8.2%。通过饲料蛋白质水平与特定生长的回归分析,获得凡纳滨对虾幼虾最大生长饲料蛋白质需要量为46.5％。     

蛋白质水平及能量蛋白比对克氏原螯虾生长与蛋白酶活力的影响

用3种不同蛋白质水平及能量蛋白比(E/P)水平饲料投喂克氏原螯虾,分析比较不同饲料对克氏原螯虾生长及蛋白酶活力的影响.试验结果表明,当饲料蛋白质水平为31.86%、E/P为35.85 kJ/g时,克氏原螯虾生长最快.随着饲料蛋白质含的上升, 克氏原螯虾肠蛋白酶活力无显著变化(P＞0.05),肝胰脏、胃蛋白酶活力显著增强(P＜0.05);饲料E/P水平未引起胃、肠、肝胰脏蛋白酶活力的显著变化(P＞0.05),当饲料蛋白质水平为31.47%、E/P为40.42 kJ/g时,克氏原螯虾蛋白酶活力最高.