饵料对稀有鮈鲫幼鱼和成鱼生长的影响及摄食优化策略研究

在实验室适宜的饲养条件下,进行不同发育阶段的稀有鮈鲫为期30 d的摄食-生长实验,研究3种饵料在投喂量分别为鱼体湿重的3.0%、4.0%和6.0%的3种摄食水平条件下,对稀有鮈鲫幼鱼(初始湿重为(0.0749±0.02)g)和成鱼(初始湿重为(0.2603±0.06)g)的生长影响。结果表明,不同摄食水平组的稀有鮈鲫幼鱼的相对增重率和特定生长率随摄食水平的增加而增加,但饲料转化率呈下降趋势;而稀有鮈鲫成鱼的相对增重率、特定生长率和饲料转化率的变化趋势基本相同。适宜摄食水平随稀有鮈鲫体重的增加而降低,稀有鮈鲫幼鱼和成鱼的适宜饵料分别为O.S.I.微细颗粒和O.S.I.细颗粒,适宜摄食水平分别为6.0%和4.0%。     

摄食水平和氨氮对梭鱼幼鱼食物消化及生长的影响

以鮻鱼(Liza haematocheila)为研究对象,采用半静态实验法探讨了摄食水平和氨氮联合作用对鮻鱼幼鱼摄食、食物转化率、生长、肠胃蛋白酶等方面的影响。结果表明:氨氮对鮻鱼幼鱼的摄食具有抑制作用,高浓度氨氮(3.32mg·L-1)对幼鱼摄食的抑制率达28.78%。鮻鱼幼鱼对食物的转化率(FCE)随氨氮浓度升高而减小,随着摄食水平的增加而增加,FCE最大值出现在饱食未添加氨氮组(BS5),为19.83%;最小值出现在低摄食水平的高浓度氨氮组(HS1),为-22.19%。鮻鱼幼鱼特定生长率(SGR)的增长水平受摄食水平和氨氮的影响与幼鱼的FCE变化一致。氨氮对实验幼鱼肠胃蛋白酶活性的影响因摄食水平而不同,本实验中,仅饱食条件下高浓度氨氮对幼鱼的肠胃蛋白酶有显著抑制效应,这可能与氨氮胁迫情况下幼鱼摄食量较小有关;氨氮浓度相同时,对照组和低氨氮浓度组鮻鱼幼鱼肠胃蛋白酶活性受摄食水平影响显著,而高氨氮浓度条件下,由于饱食组幼鱼肠胃蛋白酶活性受抑制,导致摄食水平对肠胃蛋白酶活性影响不显著。研究证实,摄食水平是影响鮻鱼生长及肠胃蛋白酶活性的主要因素,氨氮会抑制鮻鱼摄食,进而影响蛋白酶活性。     

摄食烤羊肉的多环芳烃暴露

多环芳烃(PAHs)对人体健康危害很大,而摄食暴露是PAHs暴露的重要途径之一.PAHs在人体内会代谢成包括羟基多环芳烃(OH-PAHs)在内的一系列代谢产物,并最终随尿液排出体外.为了研究摄入烧烤羊肉导致的PAHs暴露和暴露者尿样中OH-PAHs的含量和动态变化,征集了4名志愿者,在控制条件下一次性定量摄入烧烤羊肉后...     

南京市蔬菜中滴滴涕和六六六的残留及摄食暴露分析

为研究有机氯农药在食物中的残留及人群的摄食暴露,在2015年5月采集了南京市居民普遍食用的10种蔬菜,利用气相色谱-质谱联用仪(GC-MS)进行检测。研究表明滴滴涕(DDTs)和六六六(HCHs)在蔬菜中均有检出,∑DDTs的残留量为1.78~5.29 ng·g~(-1),∑HCHs的残留量为0.21~4.77 ng·g~(-1),其中∑10OCPs(有机氯农药)含量最高的蔬菜是藕(10.07 ng·g~(-1)),含量最低的是青菜(2.32 ng·g~(-1))。通过来源分析发现,蔬菜中DDTs可能有新的输入,而HCHs则主要源于历史残留。通过对不同人群的每日摄取量(EDI)进行摄食暴露分析发现,儿童的摄食暴露量要高于同性别其他年龄段人群,在儿童和未成年阶段,男性的暴露量普遍高于女性,而在成年和老年阶段,男性的暴露量低于女性。平均而言,各年龄段人群对γ-HCH和DDTs的日均口摄暴露量(EDI)值远低于联合国粮农组织和世界卫生组织(FAO/WHO)所规定的ADI值,表明在目前蔬菜消费量下,南京市居民通过摄入蔬菜引起的健康风险水平较低。     

干湿交替对福寿螺摄食和生长的影响

福寿螺（Pomacea canaliculata）被世界自然保护联盟列入世界100种恶性外来入侵物种黑名单,在我国南方已对水稻生产造成严重危害。为了探索通过水分调控来防治福寿螺的方法,本研究模拟福寿螺野外生存条件,探讨不同干湿交替条件下福寿螺摄食和生长的情况,来分析干旱胁迫对其体重增长率(Weight growth rate,WGR)、摄食率（Feeding rate,FR）、食物转化率(Food conversion ratio,FCR)、特定生长率（Specific growth rate,SGR）等的影响。结果表明：福寿螺在干湿交替条件下,其WGR、FR、FCR、SGR均受到明显抑制,甚至出现负值的情况;福寿螺的壳高随着有水时长的延长而增加,出现干旱时间越长,壳高增长越缓慢的现象;福寿螺在短时期干湿交替条件下发生部分补偿生长现象,这种补偿生长效应可能主要是通过饥饿后摄食水平提高而实现的,但超出一定限度时则不能补偿生长。根据上述结果,可以认为福寿螺在缺水条件下无法正常生长,且影响程度随着干旱时间的增加而增大。此外,福寿螺普遍会在旱后复水180min内钻出土壤,因此,可利用此时机防治福寿螺,及时避免其损伤水生作物。本研究结果可为稻田福寿螺的综合防治和水资源利用管理提供理论参考。     

慢性氨氮胁迫对黄颡鱼摄食、生长及血液指标的影响

挑选规格相近的健康黄颡鱼幼鱼分别饲养在氨氮浓度为3.36 mg L-1(A1)、6.72 mg L-1(A2)、13.44 mg L-1(A3)、26.88 mg L-1(A4)的水体中,对照组(A0)用不加外源氨氮的自然晾晒的自来水饲养.每组放养试验鱼30尾,暴露56d.结果表明,非离子氨对黄颡鱼幼鱼的摄食、生长及血液指标存在显著影响(P<0.05),而对鱼体成分的影响不显著(P>0.05).随着非离子氨浓度升高,高浓度组摄食率明显下降,饲料利用率降低,生长缓慢,特定生长率(Specialgrowth rate,SGR)和存活率都较对照组低.血氨浓度随非离子氨浓度升高而显著升高(P<0.01),各处理组血氨浓度远低于其所处环境总氨氮(Total ammonia,TAN)浓度,而血浆尿素氮(Urea nitrogen,Ur-N)水平逐渐降低但差异不显著.A3和A4碱性磷酸酶(k p p,AKP)活性和皮质醇(Cortisol)水平升高较快,A1和A2尽管呈上升趋势,但与对照组差异不显著(P>0.05).血糖(Glucose,GLU)浓度总体上表现为降低的趋势,2个高浓度组(A3和A4)下降速度较快.谷丙转氨酶(Alamine aminotransferase,ALT)和谷草转氨酶(Aspartate aminotransferase,AST)活性总体呈升高趋势,非离子氨浓度越大其升高趋势越明显.因此,黄颡鱼幼鱼不宜长期生活在高浓度的氨氮胁迫环境中,适宜的养殖水体中氨氮应该保持在低于6.72 mg L-1水平.     

乌鳢仔鱼生化成分变化与其行为的关系

研究了１～１６ｄ龄乌鳢仔鱼水分、Ｎａ＋、Ｋ＋、脂肪和蛋白质含量的变化及其主要摄食行为．结果表明，初孵仔鱼含水量为５０．１５％～５２．４０％，并随发育进展持续上升到８６．３５％～８６．８６％，而仔鱼干重则在第６ｄ最低．Ｎａ＋、Ｋ＋在仔鱼前期波动较大，第８ｄ后稳步上升，脂肪食量在孵出后的前４ｄ基本上保持不变，第５ｄ下降１５．８５％，第６ｄ下降３４．３８％，此后一直下降．蛋白质含量前８ｄ变化很小，第８ｄ后开始大幅上升．结合行为学观察认为，油球在仔鱼前期主要作为“浮力器官”（ｂｕｏｙａｎｃｙｏｒｇａｎ），在后期则可补偿摄入能量的不足．     

不同碳链长度的离子液体对大型溞摄食行为的影响

用细胞计数法研究了不同碳链长度的离子液体对大型溢滤水率和摄食率的影响.结果表明,随着碳链长度的增加,离子液体对大型溞的48 h急性毒性增大,其LC50在49μg/L和15 326μg/L之间.不同碳链长度的离子液体都显著地降低了大型溞的滤水率和摄食率,其最大浓度处理组分别比对照降低T60%～84%.结果提示,离子液体对大型溞摄食行为具有很大的毒性影响,因此对水生环境可能也具有潜在的生态风险.图1表1参25     

春季昌江大型底栖无脊椎动物群落结构及功能摄食类群的空间分布

于2009年4~5月采集鄱阳湖支流昌江的大型底栖无脊椎动物,研究其物种组成及其功能摄食类群的空间分布状况,并通过功能摄食类群组成评价昌江流域河流的生境状况.结果表明:四节蜉、宽基蜉、细蜉和多突癞皮虫为昌江的优势类群,其中四节蜉为昌江流域内4条支流共同的优势类群.冗余分析表明,昌江底栖动物主要受水体中总溶解固体和溶解氧的影响.收集者为昌江各支流主要的功能摄食类群;对昌江流域支流间功能摄食类群参数进行比较发现,指示物质循环方面的参数为昌江干流>北河>东河>大北河,指示物质的纵向输送能力方面的参数为大北河>东河>北河>昌江干流,指示沿岸物质的输入方面的参数为大北河>昌江干流>东河>北河.对各功能摄食类群参数和环境因子进行相关分析,流量的增加会加速河流中沿岸凋落物的输入,水温的升高会加速凋落物的分解,进而会增加河流中有机碳和其他溶解物质的含量.     

钙型斜发沸石铵离子交换平衡的研究

测定了在不同pH值下人工改型所得钙型斜发沸石对NH4^ 的全交换容量、对NH4^ 的等温交换平衡曲线，进一步研究了其部分热力学特性。结果表明，钙型斜发沸石对NH4^ 交换总量随pH值的升高而降低，在pH值为7时为79．321mmol／100g，该离子交换过程可自发进行，且其选择性随温度的升高而降低。研究成果可为沸石法处理含氨氮废水的进一步研究提供一定的理论依据。     

Light intensity and the feeding behaviour of herring,Clupea harengus

An infra-red sensitive video-recording technique was used to study the effects of darkness and light intensities from 0.0001 to 270 photopic lx on the feeding behaviour of herring (Clupea harengus L.). When offered natural zooplankton, consisting of a mixture ofCalanus finmarchicus, Euchaeta norvegica, Oithona similis, Balanus sp. nauplii, and crustacean nauplii as prey, the fish fed by biting (snapping) at light intensities above a threshold of 0.001 lx and were size-selective, taking the larger organisms first. When fed on pure cultures of CaliforniaArtemia sp. nauplii (San Francisco Bay brand), the threshold light intensity was 0.01 lx. Swimming speed increased with increasing light intensity when the fish were actively feeding by biting. When the fish were filter-feeding on high densities ofArtemia sp. nauplii in the light, they continued to school and swimming speed was not related to light intensity.     

Feeding,starvation and metabolic rate in the shore crab Carcinus maenas

The relationship between food intake and metabolic rate (as measured by oxygen consumption) of Carcinus maenas (L.) was studied. The metabolic rate of feeding crabs which had been starved for a short period increased, and several days were required for it to return to its original level. During prolonged starvation, the metabolic rate of C. maenas fell in two stages. The first reduction was to about 60% of the feeding level; this occurred during the first week of starvation. There was then a further reduction to about 40% of the feeding level and, at this level of metabolism, the crabs were able to survive for 3 months, with only 50% mortality; most of this occurred in the last 2 weeks. Metabolic rate was found to affect food intake; crabs acclimated to 24°C took 2.4 times as much food as crabs acclimated to 10°C, although the metabolic levels of the two groups differed by a factor of only 1.4. From the results obtained when the crabs were starved and when starved crabs were fed, it is suggested that, during starvation, the metabolic rate of C. maenas first drops from the elevated feeding level to a level at which carbohydrate reserves are utilised, and subsequently to a minimum level at which lipid reserves and proteins are used.     

Light and social effects on the free-running circadian activity rhythm in common marmosets (Callithrix jacchus; Primates): social masking,pseudo-splitting,and relative coordination

Summary The variability of period of the free-running circadian activity rhythm (CAR) and the degree to which it is affected by social factors was studied in diurnal marmosets (Callithrix jacchus: Primates, Cebidae), kept either singly or in pairs. Under continuous light intensities between 10^-1 and 10² lx, the spontaneous period was always shorter than 24h. It varied in relation to the amount of time spent under constant conditions (after-effects). There was some evidence of an effect of light intensity on free-running period, but no clear correlation between the two. Mutual acoustic social contact caused some males to exhibit pseudo-splitting, ascribable to positive social masking, and in many cases also resulted in relative coordination of the free-running CAR. True social entrainment, however, was not produced. The possibility that the latter could occur under some conditions is discussed, as well as the neural pathways that might mediate the observed acoustically induced social effects on the central nervous system pacemaker(s) of the circadian timing system.     

水体扰动对铜绿微囊藻生长影响的规律及原因

在实验室条件下模拟不同扰动状态的水体,探讨铜绿微囊藻的生长与水体扰动之间的关系.结果表明,水体的扰动对铜绿微囊藻的生长同时存在促进和抑制作用.低速度扰动时,促进作用占主导地位;高速度扰动时,抑制作用占主导地位.实验发现中营养化条件下,当温度为25℃,光照为4000 lx,光暗比为12 h∶12 h时,300 r.min-1的扰动速度是铜绿微囊藻生长的临界速度.扰动过程可以为铜绿微囊藻的光合作用提供充足的二氧化碳是其能够促进铜绿微囊藻生长的潜在原因.     

Circadian rhythm of swimming activity in juvenile pink salmon (Oncorhynchus gorbuscha)

The circadian rhythm of swimming activity and the role of the daily illumination cycle in the synchronization of this rhythm were studied in individual juvenile pink salmon. Sixty eight percent of all fish examined (n=38) were day-active when exposed to a 12 h L:12 h D cycle; the remaining fish were nocturnally active. One half of the fish tested under laboratory conditions of continuous, constant light intensity (LL) and constant temperature showed unambiguously endogenous activity rhythms with circadian periods for up to 10 d. The remaining fish were arrhythmic. Mean period length of the free-running activity rhythms for diurnal fish in LL shortened with constant light intensity increasing from 6 to 600 lx, as predicted by the circadian rule. In contrast, mean free-running period for nocturnal fish did not vary significantly with similarly increasing constant light intensity. Mean swimming speed (activity level) of both diurnal and nocturnal fish increased significantly with increasing light intensity. This is suggestive of a positive photokinetic response. When subjected to a phase-delayed LD cycle, the fish resynchronized their daily rhythms of activity with this new LD cycle after only one transient cycle in most instances. Hence, the timing of the daily activity rhythms appeared to occur through the direct masking action of the illumination cycle on activity, rather than through entrainment of an endogenous circadian system.     

丁虫腈在环境中的降解特性

采用室内模拟试验研究丁虫腈在水体中的光解、水解及其在3种不同类型土壤中的降解特性。结果表明,丁虫腈在酸性和中性条件下比较稳定,不易水解,而在碱性条件下水解较快,在50℃、pH值为9．0的缓冲溶液中降解半衰期为26．7d。通过对水解产物的鉴定,推断丁虫腈的水解机理为碱催化水解。在[光]照度为2500lx、紫外强度为25I．LW·cm-2的人工光源氙灯条件下,丁虫腈的降解半衰期为1．5h,主要降解产物为氟虫腈。丁虫腈在太湖水稻土、江西红壤和陕西潮土中培养180d后均未发生明显降解,表明该农药在土壤中较难降解。     

Provisioning rules in tree swallows

Conflict between parents and offspring may result in offspring exaggerating their needs and parents devaluing their begging signals. To determine whether this occurs, it is first necessary to establish the link between need, begging and parental response. The purpose of our study was to examine these relationships in tree swallows (Tachycineta bicolor). Parents preferentially fed nestlings that begged sooner, reached higher and were closer to the front of the nestbox (Fig. 1). Begging intensity of both individuals and entire broods increased with relatively long periods between feeding visits. Within broods, parents responded to increased begging intensity by increasing their feeding rate, although this effect was relatively weak. Large and small nestlings did not differ in their begging behavior and all nestlings, regardless of size, were fed at similar rates. Despite the overall equity in feeding, male parents preferentially fed larger nestlings while female parents fed smaller nestlings. Nestlings did not increase their begging intensity in response to begging by nestmates. Our results suggest that begging is related to need in this species and that parents respond to variation in begging intensity. Received: 4 May 1995/Accepted after revision: 17 December 1995     

雨生红球藻3个株系的生长及对光盐反应初探

对雨生红球藻3个株系（No.3、No.712和No.797)的生长、对诱导虾青素形成的光盐因子的反应进行了比较，结果表明：No.3、No.712和No.797的生长速率分别为0．128d^-1,0.137d^-1和0.144d^-1；外加盐的量较大（4gL^-1)时导致雨生红球藻细胞数的减少，而外加盐浓度较低（2gL^-1)时，细胞数的反应因株系和光照的不同而有所差异；盐和强光照均导致静细胞比例显著增加；盐的加入仅在弱光照下诱导雨生红球藻3个株系的虾青素累积，在强光照下却导致件株系虾青素含量的下降，强光照下不外加盐时No.3、NO.712和No.797藻液的虾青素含量无显著差异，分别为2.15、2.77和2．45mg L^-1。图1表2参12     

Life-history parameters and vertical distribution of Maurolicus muelleri in Masfjorden in summer

Population characteristics, individual life-history variables, feeding and vertical distribution of the mesopelagic fish Müller's pearlside Maurolicus muelleri collected in 1990 in Masfjorden, western Norway, are reported as well as environmental variables from the fjord. Minimum size at maturity was far smaller than reported from previous investigations in the same region. Fecundity was size-dependent and total egg numbers were higher than reported from other investigations of M. muelleri world wide, while the number of maturing eggs was far lower than observed in the same region earlier. Food concentration in the fjord was an order of magnitude lower than previous early summer observations, and several factors indicated that feeding opportunities may have been low for a long period. Daily feeding rate (g prey g^-1 fish) decreased with increasing fish size. These observations fit well with a model of maximizing fitness by means of a flexible size at maturity. Minimum age at maturity seems to be achieved at the expense of fecundity. M. muelleri was concentrated in a 20 to 30 m deep sound scattering layer (SSL). The SSL stayed close to the surface during the night and at 100 to 180 m during the daytime. The vertical position of the SSL varied instantaneously with changes in surface light intensity, remaining at 10^-3 to 10^-4 mol m^-1 s^-1 at the top of the SSL. Stomach fullness was highest during the night; feeding intensity seems to have been peaked at dusk. Cladocerans were the main prey ranked by number, copepods by biomass. Intake of large copepods increased with fish size.     

Growth and competition of the marine diatoms Phaeodactylum tricornutum and Thalassiosira pseudonana. II. Light limitation

The marine diatoms Phaeodactylum tricornutum (Bohlin) and Thalassiosira pseudonana (Hasle and Heimdal) were grown under both continous illumination and a 14 h light: 10 h dark cycle at light intensities ranging from 1.53×10^-4 to 2.95×10^-1 ly min^-1. Under both photoperiods, T. pseudonana exhibited higher division rates than P. tricornutum at high light intensities, but the reverse was true at all light intensities <3×10^-3 ly min^-1. Comparison of these results with available data on light-limited growth of other planktonic algae suggests that P. tricornutum may be unusually efficient at maintaining its cell division rate at low light intensity. This efficiency may contribute substantially to its success in turbid, nutrient-enriched mass algal culture systems, the only environments in which it is known to attain great numbers.Contribution No. 4086 from the Woods Hole Oceanographic Institution.