盐度对中华绒螯蟹雌性亲蟹代谢的影响

测定了不同盐度(0,6,12,18,24)条件下,中华绒螯蟹(Eriocheir sinensis)雌性亲蟹的耗氧率、CO2排出率及NH3 N排泄率,并研究了其呼吸熵、氧氮比、代谢率及能源物质供能比随盐度的变化情况。结果表明,体质量为(55.59±6.24)g的中华绒螯蟹雌性亲蟹,在水温(16±1)℃条件下,盐度对其耗氧率及NH3 N排泄率影响显著(P<0.05)。在实验盐度范围内(0~24),其耗氧率及NH3 N排泄率均随盐度的升高而下降,CO2排出率及代谢率的变化趋势与耗氧率一致,且盐度为6的实验组亲蟹CO2排出率及代谢率均与对照组差异不显著(P>0.05),在盐度12~24范围内,亲蟹CO2排出率及代谢率均显著低于对照组(P<0.05);呼吸熵及氧氮比均变化不显著(P>0.05);能源物质以脂肪的供能比例最大,其次是碳水化合物,蛋白质的供能比例最小。分析认为,中华绒螯蟹雌性亲蟹在生殖洄游过程中主要以脂肪作为供能物质,代谢率与能量消耗逐渐降低。     

盐度与体重对克氏原螯虾代谢的影响

在水温为20.0±0.5℃条件下,研究了不同盐度(0、3.0、6.0、9.0、12.0)和不同体重(平均体重为7~8 g、19~20 g两种规格)对克氏原螯虾的耗氧率、CO2排出率以及NH3-N排泄率的影响。结果表明,低盐度条件下(0~6.0),两种规格克氏原螯虾的耗氧率、CO2排出率和NH3-N排泄率均随着盐度的升高而显著上升(P<0.05),盐度为6的条件下代谢水平达最高值,此后随着盐度的升高耗氧率、CO2排出率和NH3-N排泄率显著下降(P<0.05);相同盐度下,小规格(平均体重为7~8 g)克氏原螯虾的耗氧率、CO2和NH3-N排泄率显著高于大规格虾(平均体重为19~20 g)。相同规格的克氏原螯虾在不同盐度条件下呼吸商、氧氮比均无显著差异(P>0.05),但是大规格的克氏原螯虾呼吸商和氧氮比显著大于小规格的虾(P<0.05),前者的代谢率极显著低于后者(P<0.01)。     

日本蟳能量代谢的研究

在室内实验条件下,测定了温度和体重对日本蟳耗氧率、排氨率和二氧化碳排泄率的影响。实验结果表明,随个体重量的增加,日本蟳单位体重的耗氧率、排氨率和二氧化碳排泄率均减小,呈负相关的幂指数关系,均符合Y=aWb模式。随温度增加,日本蟳的耗氧率、排氨率和二氧化碳排泄率均增加。根据O/N和呼吸商（Q）可知,日本蟳能量代谢的底物主要为蛋白质,其次为脂肪和碳水化合物,其比例为56∶31∶13。     

日本Xun能量代谢的研究

在室内实验条件下,测定了温度和体重对日本Ｘun耗氧率、排氨率和二氧化碳排泄率的影响。实验结果表明,随个体重量的增加,日本Ｘun单位体重的耗氧率、排氨率和二氧化碳排泄率均减小,呈负相关的幂指数关系,均符合Ｙ＝aＷ＾－b模式。随温度增加,日本Ｘun的耗氧率、排氨率和二氧化碳排泄率均增加。根据Ｏ/Ｎ和呼吸商（Ｑ）可知,日本Ｘun能量代 谢的底物主要为蛋白质,其次为脂肪和碳水化合物,其比例为５６：３１：１３。     

克氏原螯虾耗氧率和窒息点的研究

克氏原螯虾耗氧率与窒息点与体重呈负相关关系,与温度正相关;性别对耗氧率和窒息点的影响不明显;该虾耗氧率有明显昼夜之分,白天平均耗氧率为0.0294mg·g-1·h-1,夜间为0.0426mg·g-1·h-1。     

鳗苗生态适应力的初步研究

体长56.1～67.0毫米,重0.092～0.182克的鳗苗在12～18℃水温条件下的耗氧率为0.073～0.475毫克/克·小时,对±5℃和±8℃的骤变水温无异常反映;从淡水中转入2.5%食盐水中经46小时正常,转入3.5%食盐水中9.5小时全部死亡;在PH5.5～9.5淡水中经72小时安全,PH10.0经72小时50%死亡;在淡水中饥饿忍受力最长达90余天。     

大菱鲆正常代谢水平及节律性的研究

对工厂化养殖的不同规格大菱鲆(Scophamus maximus Linnaeus)的日常代谢进行了研究。结果表明,4种规格的大菱鲆表现出相同的代谢规律性,摄食对大菱鲆的代谢有明显的影响,摄食后代谢率呈迅速上升的趋势。在摄食后3～9 h内代谢率出现第1高峰值,在凌晨3:00～6:00(摄食后21-24 h)出现第2高峰值,代谢率昼、夜之间的差异不显著(P>0.05)。体重对大菱鲆的代谢有着显著的影响,4种规格9.69±3.35g、33.34±8.34g、130.18±26.75g和264.11±35.79g的大菱鲆日平均耗氧率分别为0.2702±0.0225、0.1880±0.0189、0.1592±0.0436、0.1033±0.0184mgO2/g·h,日平均氨氮排泄率分别是0.6496±0.0303、0.4560±0.0669、0.3744±0.0320、0.2831±0.0662mgN/100g·h,随着体重的增加,单位体重的代谢率呈下降的趋势(P<0.05)。     

光照对不同规格番红砗磲(Tridacna crocea)氧、氨氮及活性磷酸盐代谢的影响

在水温24-26℃下,采用室内实验生态学方法,研究了5000 lx光照强度和黑暗对壳长为(63.53±1.22) mm(S组)、(75.87±1.50) mm (M组)和(92.75±3.02) mm (L组)番红砗磲(Tridacna crocea)氧、氨氮及活性磷酸盐代谢的影响.结果显示,光照条件下,番红砗磲释放氧气,吸收氨氮和活性磷酸盐.黑暗条件下,番红砗磲代谢状况与其他双壳贝类类似.番红砗磲个体代谢率与规格密切相关:光照条件下个体越大,产氧率、对氨氮和活性磷酸盐吸收率越高;黑暗条件下,个体越大,耗氧率、对氨氮和活性磷酸盐释放率亦越高.光照条件下,番红砗磲软体部单位干重代谢率与其个体规格呈负相关,个体越大,单位干重的产氧率、氨氮和活性磷酸盐的吸收率越小.实验首次量化了不同光照条件下番红砗磲对氧、氨氮及活性磷酸盐的吸收和排泄状况,结果可为研究番红砗磲在珊瑚礁生态系统中的作用提供依据,对砗磲人工养殖也具有一定的参考.     

温度、体重和昼夜节律对大菱鲆幼鱼代谢的影响

在鱼体重相对恒定时,用流水法测定了温度、昼夜节律对大菱鲆幼鱼耗氧率、氨氮排泄率的影响;在温度相对恒定时,用静水法测定了体重对大菱鲆幼鱼耗氧率、氨氮排泄率,窒息点的影响。结果表明:在实验温度范围内,体重2.0 g的幼鱼,耗氧率随水温升高而上升;10℃时,耗氧率最低,在26℃达到最高;在18℃以上,温度再升高,大菱鲆幼鱼将分配更多的能量用于呼吸代谢。体重2.0 g的大菱鲆幼鱼氨氮排泄率随水温的升高而上升;在10℃时氨氮排泄率最低,26℃达到最高;大菱鲆幼鱼的氨氮排泄比较稳定,但在较高温度水平时大菱鲆幼鱼蛋白质代谢的强度增加。     

氨氮浓度对不同体重河蚌(Anodonta woodiana)耗氧率的影响

在静水水温和水体悬浮颗粒物浓度保持相对恒定的条件下,研究了不同体重(以软组织干重计算)的河蚌(Anodonta woodiana)在3个氨氮水平下的耗氧率。结果显示:在固定的氨氮水平下,单位体重耗氧率(Or)随体重(w)增加而下降,耗氧率和体重间呈负相幂函数关系;在实验体重和氨氮浓度(n)范围内,氨氮浓度对河蚌耗氧均具有主效应,氨氮浓度和体重、耗氧率的自然对数y(以lnOr表示)可以表述为y=3.5968±0.24+0.0119±0.00n-1.0237±0.15lnw。结果表明,在试验范围内,氨氮浓度对河蚌耗氧产生增益效应,即随氨氮浓度升高,耗氧率增加,而随体重的增加,耗氧率下降。本试验中,氨氮未对河蚌产生抑制效应。     

瓦氏黄颡鱼幼鱼标准代谢的初步研究

研究了平均体质量为6.231、1.32 g和21.21 g瓦氏黄颡鱼幼鱼的标准代谢,并分析了幼鱼利用蛋白质、脂肪和糖类作为能源物的供能情况。通过测定幼鱼在禁食和静息状态下的耗氧率、排氨率和二氧化碳排出率,计算出幼鱼的呼吸熵、氧氮比和能耗率。试验结果表明,瓦氏黄颡鱼幼鱼的耗氧率、排氨率和能耗率均随幼鱼体质量的增加而显著下降(P<0.01),且耗氧率、排氨率和能耗率与体质量呈负相关关系,而呼吸熵与体质量则呈正相关关系。不同体质量幼鱼的二氧化碳排出率和氧氮比差异不显著;根据氧氮比的分析结果可知,瓦氏黄颡鱼幼鱼主要利用脂肪和蛋白质供能,且随着体质量的增长,脂肪供能的比例逐渐增大。结果显示,瓦氏黄颡鱼幼鱼对糖类的利用能力较为有限,有必要对该鱼的糖需求和利用率进行进一步的研究。     

温度对黄金鲈(Perca flavescens)耗氧率和排氨率的影响

在不同水温(15、20、25和30℃)下,对体重(46.1±4.5)g黄金鲈(Perca flavescens)的耗氧率和排氨率进行了测定与分析。结果显示:黄金鲈的耗氧率和排氨率均随温度的升高而显著增加(P<0.01);耗氧率和排氨率与温度的关系可用指数方程拟合,其方程分别为:RO=0.0682 e0.0633t,R2=0.9879;RN=2.4593 e0.0904t,R2=0.9703;随着温度的升高氧氮比(O:N)逐渐降低;耗氧Q10值和排氨Q10值均在20~25℃之间最小。结果表明:在各温度水平下黄金鲈基础代谢消耗底物主要均以蛋白质为主,脂肪其次,然而随着温度的升高,黄金鲈利用糖类和脂肪供能的比例逐渐下降,而蛋白质供能的比例逐渐增加。黄金鲈的最适生长温度为20~25℃。     

The Effect of Biomass Density,Temperature, and Substrate on Transport Survival of Market-Size Freshwater Prawn,Macrobrachium rosenbergii

Abstract

After harvest, adult prawn are often transported for sales to live markets, such as ethnic Asian outlets, in major urban centers. Poor survival during transportation has hindered development and expansion of these markets. Methodologies to increase survival during transport could contribute to industry viability. Three independent trials were conducted. In the first trial, three biomass densities (25, 50 and 100 g/L) were evaluated in 100-L, open plastic containers aerated with pure oxygen and compressed air. Water quality analyses were performed prior to stocking. After 24 hours in the model transport containers, water quality analysis was conducted and all prawn were removed, determined to be alive or dead, and each group weighed and counted. There was no significant difference (P > 0.05) for prawn survival (overall mean 98%) among the three densities. Concentrations of dissolved oxygen and nitrite were not effected by hauling density (P < 0.05). Total ammonia-nitrogen and un-ionized ammonia-nitrogen concentrations increased (P < 0.05) as biomass densities increased, though values remained within what are considered tolerable ranges. In the second trial, the effect of added substrate and temperature on transport survival was evaluated with prawns stocked at the high density (100 g/L). Two water temperatures (21°C and 26°C) with and without substrate were evaluated in a 2 × 2 factorial with three replicate, 100-L model transport containers per treatment combination (12 containers total). Factorial analysis indicated no significant statistical interaction (P > 0.05) between the presence of substrate and water temperature on any measured variable. The main effects of substrate and temperature were then analyzed separately. The presence or absence of substrate had no significant impact (P > 0.05) on prawn survival. However, temperature had a highly significantly impact (P < 0.01) on survival; prawn survival at 21°C averaged 97% compared to 24% at 26°C. The third trial was a commercial verification trial in which 500 kg of live prawn were transported to New York from Kentucky. These data indicate prawn can be successfully transported at 100 g/L for 24 hours when temperatures are maintained near 21°C. Adding substrate to the transport tank appears to provide no benefit.     

盐度骤降对近江牡蛎和长牡蛎能量收支的影响

采用实验生态学方法，研究了盐度骤降(盐度分别为10、20，自然海水为对照组)对近江牡蛎(Crassostrea ariakensis)和长牡蛎(Crassostrea gigas)生理代谢的影响。结果显示，盐度骤降对长牡蛎和近江牡蛎的耗氧率(OR)、排氨率(NR)、排粪率(FER)均有显著影响(P<0.05)，且2种牡蛎对盐度骤降的响应存在差异。长牡蛎的耗氧率、排氨率、摄食率(IR)和排粪率均在自然海水中最高，低盐对长牡蛎产生不同程度的胁迫。而近江牡蛎在盐度为20时的上述指标显著高于其他盐度处理组。通过测定不同规格牡蛎的代谢率，建立2种牡蛎在不同盐度下的代谢率与规格(湿重)的回归方程，该方程符合幂指数：Y=aWb。通过归一化处理，比较湿重在20 g时，2种牡蛎的能量分配差异。盐度为20时，近江牡蛎的呼吸代谢较强(呼吸能占16.1%)，而长牡蛎在自然海水中呼吸代谢较强(呼吸能占7.8%)，2种牡蛎的呼吸代谢均在盐度为10时较低，其中，长牡蛎呼吸能仅占0.7%。研究表明，盐度骤降对长牡蛎的影响大于近江牡蛎，小幅度的盐度骤降对近江牡蛎的能量代谢有一定的促进作用。本研究从能量代谢角度，探讨了近江牡蛎和长牡蛎对盐度骤变的响应，可为牡蛎礁修复工作和养殖生产过程中的品种选择提供参考。     

不同溶解氧水平下厚壳贻贝的贝壳开放行为和呼吸代谢

为了探讨溶解氧浓度变化对厚壳贻贝(Mytilus coruscus)摄食和代谢的影响, 分析贝壳开放行为和呼吸代谢的相关关系, 观察测定了 8 mg/L、6 mg/L、4 mg/L、2 mg/L 和 1 mg/L 溶解氧水平下厚壳贻贝贝壳开放程度、滤水率、耗氧率和排氨率, 并计算了氧氮比值。结果显示, 溶解氧浓度在 4 mg/L 及以上水平时, 厚壳贻贝的贝壳持较大程度开放, 而当溶解氧浓度降至 2 mg/L 及以下后, 贝壳逐渐关闭; 溶解氧浓度降至 4 mg/L 后, 贻贝滤水率显著下降; 溶解氧浓度在 2~8 mg/L 间, 贻贝耗氧率无显著变化, 降至 1 mg/L 后, 耗氧率显著下降; 排氨率与滤水率和耗氧率呈相反趋势, 溶解氧浓度降至 2 mg/L 后, 贻贝排氨率显著上升; 降至 4 mg/L 后, 氧氮比值显著下降; 贝壳开放程度与滤水率、耗氧率之间呈正相关关系。研究表明, 厚壳贻贝可以适应一定范围内溶解氧浓度的波动, 保持机体代谢水平相对稳定; 当环境溶解氧降至 1 mg/L 以下, 机体无法再维持正常的代谢, 厚壳贻贝部分关闭贝壳, 以降低能量消耗, 应对低氧胁迫。本研究可为厚壳贻贝低氧适应机制研究和养殖提供参考。     

The potential of mixed culture of genetically improved farmed tilapia (Oreochromis niloticus) and freshwater giant prawn (Macrobrachium rosenbergii) in periphyton-based systems

The production performance of genetically improved farmed tilapia (GIFT, Oreochromis niloticus) and freshwater prawn (Macrobrachium rosenbergii) in periphyton‐based systems were studied in farmers' ponds at Mymensingh, Bangladesh. Fifteen ponds (200–300 m² area and 1.0–1.5 m in depth) were used to compare five stocking ratios in triplicate: 100% GIFT, 75% GIFT plus 25% prawn, 50% GIFT plus 50% prawn, 25% GIFT plus 75% prawn and 100% prawn. Ponds were stocked at a total density of 20 000 GIFT and/or prawn ha^?1. Bamboo poles (mean diameter 6.2 cm and 5.5 pole m^?2) were posted in pond bottoms vertically as periphyton substrate. Periphyton biomass in terms of dry matter (DM), ash‐free DM and chlorophyll a were significantly higher in ponds stocked with prawn alone than in ponds with different combinations of GIFT and prawn. Survival of GIFT was significantly lower in ponds stocked with 100% GIFT (monoculture) whereas, that of prawn was significantly higher in its monoculture ponds indicating detrimental effects of GIFT on prawn's survival. Individual weight gains for both species were significantly higher in polyculture than in monoculture. The highest total fish and prawn yield (1623 kg GIFT and 30 kg prawn ha^?1) over 125–140 days culture period was recorded in ponds with 75% GIFT and 25% prawn followed by 100% GIFT alone (1549 kg ha^?1), 50% GIFT plus 50% prawn (1114 kg GIFT and 68 kg prawn ha^?1), 25% GIFT plus 75% prawn (574 kg GIFT and 129 kg prawn ha^?1) and 100% prawn alone (157 kg ha^?1). This combination also gave the highest economic return. Therefore, a stocking ratio of 75% GIFT plus 25% prawn at a total density of 20 000 ha^?1 appeared to be the best stocking ratio in terms of fish production as well as economics for a periphyton‐based polyculture system.     

Effect of dietary protein and lipid level on metabolic utilization of diets by european sea bass (Dicentrarchus labrax) juveniles

Two trials were performed with sea bass juveniles to study the effect of dietary protein (trial I) and lipid (trial II) levels on the metabolic utilization of diets at 25 °C. The effect of water temperature (18 and 25 °C) on metabolism was also tested in trial I. For that purpose, oxygen consumption and ammonia excretion were measured both in fed and in 9-days starved fish. In trial I, diets were formulated to be isoenergetic (GE: 19.4 kJ g^–1) and to have 36, 42, 48 and 56% protein; in trial II, diets were formulated to be isonitrogenous (48% protein) and to have 12, 18, 24 and 30% lipid. In trial I, feed intake (g kg^–1 day^–1), and daily ammonia excretion and oxygen consumption significantly increased with water temperature. However, when expressed relatively to intake there was no significant effect of temperature on ammonia excretion (% N intake) or heat production (% GE intake). Heat increment of feeding (% GE intake) was neither affected by diet composition nor by water temperature. The relative contribution of protein catabolism to total energy expenditure significantly increased with dietary protein level, but was not affected by water temperature. In trial II, both daily ammonia excretion and oxygen consumption were inversely correlated to dietary lipid levels. Nitrogen excretion, heat production, heat increment of feeding, non-fecal losses (% intake) and the relative contribution of protein to total energy expenditure were also inversely related to dietary lipid levels. Results of this study indicate that the main effect of water temperature was to modify feed intake, not the metabolic utilization of diets. Indeed, expressed relatively to nitrogen or energy intakes, both nitrogen and energy budgets were not significantly affected by water temperature. A decrease of dietary protein to energy ratio, by modifying either dietary protein or lipid levels, spared protein utilization for metabolism, and this effect was essentially due to a decrease of non-fecal nitrogen excretion and of the heat increment of feeding.     

Oxygen Consumption and Ammonia Excretion of the American Eel Anguilla rostrata Fed Diets with Varying Protein Energy Ratios and Protein Levels

The effect of protein/energy ratio and protein level on utilization of protein and energy as indicated by oxygen consumption and ammonia production was investigated. When protein/energy ratio of the diet was optimum, there was no significant increase in ammonia production, indicating no increase in catabolism of protein for energy as protein levels increased. However, when the protein/ energy level was below optimum, there was a significant ( P < 0.05) increase in ammonia production as protein increased, indicating increased catabolism of protein for energy. However, there was no significant increase in oxygen consumption rate.