Diet overlap between the endemic fish Anablariflus grahami(Cyprinidae) and the exotic noodlefish Neosalanx taihuensis (Salangidae) in lake Fuxian, China

We studied diet composition and overlap of the exotic noodlefish (Neosalanx taihuensis) and the endemic fish Anaborilius grahami in a deep, oligotrophic lake in the Yunnan Plateau. A. grahami dominated the fish community in Lake Fuxian before the invasion of N. taihuensis in 1982, but it is now in the process of extinction, corresponding with an explosive increase in N. taihuensis population. Schoener's index (alpha=0.773) indicate that N. taihuensis and A. grahami have significant diet overlap, with both fish feeding mainly on zooplankton. An increased proportion of littoral prey, such as Procladius spp., Coleoptera, and epiphytes, in the diet of A. grahami indicated that this endemic fish shifted its main habitat from the off-shore zone in the late 1980s to the littoral zone at the present. A difference in reproduction between the two fishes, along with the overfishing, may have exacerbated the occupation of A. grahami's pelagic niche by N. taihuensis. The endemic species has shown large competitive disadvantage for food and space in the presence of N. taihuensis.

Effect of several feeding stimulants on diet preference by juvenile gibel carp (Carassius auratus gibelio), fed diets with or without partial replacement of fish meal by meat and bone meal

The objectives of this work were to study the effects of several feeding stimulants on gibel carp fed diets with or without replacement of fish meal by meat and bone meal (MBM). The feeding stimulants tested were betaine, glycine, L-lysine, L-methionine, L-phenylalanine, and a commercial squid extract. Three inclusion levels were tested for each stimulant (0.18, 0.5%, and 1% for betaine and 0.1, 0.25 and 0.5% for the other stimulants). Two basal diets (40% crude protein) were used. one with 26% fish meal (FM), and the other with 21% fish meal and 6% MBM, Betaine at 0.1% in the fish meal group and at 0.5% in the meat and bone meal group was used in all experiments for comparison among stimulants. In the experiment on each stimulant, six tanks of fish were equally divided into two groups, one fed the FM diet, and the other fed the MBM diet. After 7 days' adaptation to the basal diet, in which the fish were fed to satiation twice a day, the fish were fed for another 7 days an equal mixture of diets containing varying levels of stimulants. Each diet contained a unique rare earth oxide as inert marker (Y2O3, Yb2O3, La2O3, Sm2O3 or Nd2O3). During the last 3 days of the experiment, faeces from each tank were collected. Preference for each diet was estimated based on the relative concentration of each marker in the faeces. Gibel carp fed the FM diet had higher intake than those fed the MBM diet, but the difference was significant only in the experiments on betaine, glycine and L-methionine. None of the feeding stimulants tested showed feeding enhancing effects in FM diets. All feeding stimulants showed feeding enhancing effects in MBM diets. and the optimum inclusion level was 0.5% for betaine, 0.1% for glycine, 0.25% for L-lysine, 0.1% for L-methionine. 0.25% For L-phenylalanine. and 0.1% for squid extract. The squid extract had the strongest stimulating effect among all the stimulants tested. (C) 2001 Elsevier Science B.V. All rights reserved.

抗 LDH－C4 IgA 和IgG 抗体在粘膜免疫系统的分布及其抗生育作用的研究

已有的研究表明，小鼠背部携带能分泌抗原特异的IgA 单克隆抗体的杂交细 胞瘤，可以保护小鼠抵抗微生物和病毒等多种病原体经粘膜途径感染机体。我们 利用背部携带能分泌抗精子特异抗原（LDH-C4）的IgA 和IgG 杂交细胞瘤、以 及抗DNP 的IgA 骨髓细胞瘤的小鼠为动物模型，采用定量ELISA 法研究了抗 LDH－C4 IgA 与抗DNP IgA 单克隆抗体在呼吸道、肠道及生殖道内转运和分布， 抗LDH-C4 IgG2b 在肠道内转运与分布，以及抗LDH-C4 IgA 和IgG 单克隆抗体 在体内抗生育作用。 研究结果表明，带瘤小鼠血液中含有较高水平抗原特异的 IgA 和IgG 单克 隆抗体。PA4 和MOPC IgA 单克隆抗体在呼吸道、肠道以及雌性生殖道分泌物 内有较高的分布水平。在肠道，PA4 和MOPC IgA 单克隆抗体的分布水平显著 高于IgG（p<0.01 和p<0.05）。在肠道和生殖道的不同部位，IgA 抗体的分布水 平不同。在肠道，结肠分泌物中的IgA 单克隆抗体显著高于其它肠道部位 （p<0.01）。在生殖道，IgA 单克隆抗体分布水平以子宫角分泌物中最高。雄性 的前列腺也有较高的IgA 抗体水平。在呼吸道、肠道以及雌性生殖道相应部位的 分泌物内，PA4 IgA 单克隆抗体的水平显著高于MOPC IgA 单克隆抗体的分布水 平（p<0.05）。PA4 和MOPC IgA 单克隆抗体在粘膜分泌物内的分布水平差异可 能与其IgA 聚合形式的不同有关。另外，除气管外，在两时间点间分泌物中的 IgA 抗体水平没有显著差异。 检测背部带瘤小鼠交配后的两细胞胚胎期，发现携带PA4 和G2b 杂交细瘤 的雌性小鼠的受精率与对照组并没有显著的差异，这表明抗LDH-C4 IgA 和IgG 单克隆抗体在体内不能明显抑制小鼠的精子和卵子的结合或受精过程。注射细 胞后的27 天，检测鼠着床胚胎时，发现带瘤两性小鼠均携带PA4 时或者只有 雌性携带PA4 杂交瘤时，以及雌雄两性小鼠均携带G2b 杂交瘤细胞时，交配后的怀孕率与能分泌抗DNP 抗体的MOPC 的骨髓瘤细胞瘤的相应组别相比，显 著降低（p<0.01）。但PA4 各组与G2b 各组之间无显著差异(p>0.05）。然而，雌 雄的小鼠均带瘤时，最高怀孕减少率未能达100%。这些结果提示，抗LDHC4 IgA 和IgG 单克隆抗体在小鼠体内不能有效地抑制小鼠的精子与卵子的结 合，但能显著地抑制小鼠受精后胚胎的发育。抗LDH-C4 的IgA 和IgG 单克隆 抗体单独存在时，在体内均具有抗生育作用，但不能完全抑制生育。

抗LDH-C4 IgA和IgG抗体在带瘤小鼠生殖道和其它粘膜分泌物内分布特性的研究

中文摘要 　 已有的研究表明，小鼠背部携带能分泌抗原特异的IgA单克隆抗体的杂交细胞瘤，可以保护小鼠抵抗微生物和病毒等多种病原体经粘膜途径感染机体。我们利用背部携带能分泌抗精子特异抗原（LDH-C4）的IgA和IgG杂交细胞瘤、以及抗DNP的IgA骨髓细胞瘤的小鼠为动物模型，采用定量ELISA法研究了抗LDH-C4 IgA与抗DNP IgA单克隆抗体在呼吸道、肠道及生殖道内转运和分布，抗LDH-C4 IgG2b在肠道内转运和分布，以及抗LDH-C4 IgA和IgG单克隆抗体与体内抗生育作用的关系。研究结果表明，带瘤小鼠血液中含有较高水平抗原特异的IgA和IgG单克隆抗体。PA4和MOPC IgA单克隆抗体在呼吸道、肠道以及雌性生殖道分泌物内有较高的分布水平。在肠道，PA4和MOPC IgA 单克隆抗体的分布水平显著高于IgG（p < 0.01和p < 0.05）。在肠道和生殖道的不同部位，IgA抗体的分布水平不同。在肠道，结肠分泌物中的IgA单克隆抗体显著高于其它肠道部位（p < 0.01）。在生殖道，IgA单克隆抗体分布水平以子宫角分泌物中最高。雄性的前列腺也有较高的IgA抗体水平。在呼吸道、肠道以及雌性生殖道相应部位的分泌物内，PA4 IgA单克隆抗体的水平显著高于MOPC IgA单克隆抗体的分布水平（<0.05）。PA4和MOPC IgA单克隆抗体在粘膜分泌物内的分布水平差异可能与其IgA聚合形式的不同有关。另外，除气管外，在两时间点间分泌物中的IgA抗体水平没有显著差异。检测背部带瘤小鼠交配后的两细胞胚胎期，发现携带PA4或G2b杂交细胞瘤的雌雄小鼠的受精率与对照组并没有显著性差异，这表明抗LDH-C4 IgA和IgG单克隆抗体在体内不能显著抑制小鼠的精子和卵子的结合或受精过程。注射细胞后的27天，检测着床胚胎时，发现带瘤两性小鼠均携带PA4时或者只有雌性携带PA4杂交瘤时，以及雌雄性小鼠均携带G2b杂交瘤时，交配后的怀孕率与带能分泌抗DNP抗体的MOPC骨髓瘤细胞瘤的相应组别相比，显著降低（p < 0.01）。但PA4各组与G2b各组之间无显著差异（p < 0.05）。然而，雌雄小鼠均带瘤时，最高怀孕减少率也未达到100%。这些结果提示，抗LDH-C4 IgA和IgG单克隆抗体在小鼠体内不能有效地抑制小鼠的精子和卵子的结合，但能显著地抑制小鼠受精后胚胎的发育。抗LDH-C4 的IgA或者IgG单克隆抗体单独存在时，在小鼠体内均具有抗生育作用，但不能完全抑制生育。

抗LDH-C4的IgA单克隆抗体在生殖道局部的分布

为了弄清生殖道内抗体，特别是IgA抗体的准确来源和它的调控因子，同时也为了弄清生殖的局部免疫与典型的粘腊免疫之间的关系，以同位素标记的针对精子特有抗原乳酸脱氢酶C4(LDH-C4)的多聚IgA单抗及其单体，与小鼠精子发生反应的IgA单抗，以及LDH-C4特异的IgG抗体，尾静脉注射给雌雄Balb/c小鼠，4小时后测定小鼠的生殖道及其分汾物，肠道、呼吸道及其分泌物，各相关淋巴组织以及其它器官内这些抗体的分布。还研究了特异抗原刺激、性激素等对这些抗体分布状况的影响。

抗小鼠乳酸脱氢酶C4（LDH-C4）IgA单克隆抗体的制备及其对精子功能的影响

乳酸脱氢酶C4 （LDH-C4）是一种人和哺乳动物精子特有的乳酸脱氢酶同功酶。用纯化的小鼠LDH-C4 免疫动物，有一定的避孕效果。这种避孕效果与血清特异性抗体水平并不完全一致。这可能是由于受精过程是在生殖道内进行的，而生殖道内又有粘膜免疫因素存在。IgA抗体是生殖道内的主要抗体成分，研究抗LDH-C4 IgA抗体的抗精子作用有助于了解局部分泌性免疫系统在抗精子免疫避孕中的作用。由于足够量的特异性IgA抗体难于从动物或人粘膜分泌液中分离到，为了获得供体内外试验用的该种抗体，直接证明它在抗生育方面的作用，我们采用一种特殊的免疫方法制备了一系列的抗LDH-C4的单克隆抗体，包括6株IgA和9株IgM。这种免疫方法的主要特点是将抗原直接注射到派伊尔氏淋巴小结（PP）或小肠腔内。ELISA检测表明，按这种方法免疫后，分泌IgA的克隆出现的比例明显高于常规免疫的结果。这是因为PP是粘膜免疫的中枢，其中含有大量的IgA前体细胞，直接将抗原注射到PP内有助于刺激IgA前体细胞的分化和增殖，诱导局部分泌性免疫反应。我们用所得到的单克隆抗体研究了LDH-C4在人，小鼠和树鼩精子表面的定位。结果表明，大多数单克隆抗体可以结合到这些精子的表面；不同的单抗在同一物种的精子表面呈现不同的结合区域。这一方面说明来源于人，小鼠和树鼩的LDH-C4的抗原决定簇有很高的同源性；另一方面提示LDH-C4在精子表面不同的区域所暴露的抗原决定簇不同。初步的功能试验表明，某些抗LDH-C4的IgA单克隆抗体可以凝集或制动精子，说明生殖道内的IgA抗体可以通过凝集和制动作用来影响精子的功能，从而影响精子的受精力。

基于C4.5决策树的流量分类方法

近年来,利用机器学习方法处理流量分类问题成为网络测量领域一个新兴的研究方向.在现有研究中,朴素贝叶斯方法及其改进算法以其实现简单、分类高效的特点而被广泛应用.但此类方法过分依赖于样本在样本空间的分布,具有潜在的不稳定性.为此,引入C4.5决策树方法来处理流量分类问题.该方法利用训练数据集中的信息熵来构建分类模型,并通过对分类模型的简单查找来完成未知网络流样本的分类.理论分析和实验结果都表明,利用C4.5决策树来处理流量分类问题在分类稳定性上均具有明显的优势.

Influence of several non-nutrient additives on nonspecific immunity and growth of juvenile turbot, Scophthalmus maximus L.

The effects of three non-nutrient additives on nonspecific immunity and growth of juvenile turbot (Scophthalmus maximus L.) were studied in this feeding experiment. The five treatments are basal diet alone, basal diets containing three different additives [0.4 g kg(-1) of xylo-oligosaccharides (XOS), 1.3 g kg (-1) of yeast cell wall and 0.8 g kg (-1) of bile acids] individually or in combination. Two hundred and twenty-five turbots (average initial weight 151.3 +/- 11.3 g) were randomly allotted in five treatments with three replicates within each treatment in a 72-day period. Comparing with basal diet group, activities of C3, C4, phagocyte, lysozyme, specific growth rate and feed conversion rate in yeast cell wall, XOS and the combined groups was enhanced significantly (P < 0.05); however, these parameters in bile acid groups were increased slightly (P > 0.05) except for phagocyte (P < 0.05); superoxide dismutase activity in additive groups was not significantly increased (P > 0.05) except for the combined group (P < 0.05). In conclusion, supplementation of yeast cell wall and XOS enhanced the nonspecific immunity of juvenile turbot. Synergistic or additive effect of the three additives was not observed.

Diet-induced changes in lipid and fatty acid composition of Artemia salina

The influence of diet on lipid and fatty acid composition of the brine shrimp Artemia salina nauplii was investigated. Various diets with different lipid composition and fatty acid profiles were fed to nauplii for 2 weeks. The lipid composition of microalgal diets, Isochrysis galbana, Phaeodactylum tricornutum and Nannochloropsis oculata and baker's yeast was analyzed. Newly hatched nauplii were examined before the feeding experiment. It was shown that Artemia was able to incorporate and selectively concentrate some dietary lipids. Depot lipids were more sensitive to changes in the dietary lipid composition than the main structural lipids, polar lipids and sterols. Variations in the content of the lipid classes correlated with stage of development of the animal. The fatty acid composition of the animal varied with that of diet. The concentrations of saturated fatty acids were apparently supported in the nauplii by biosynthesis de novo. The acid 16:1(n-7) originated from the food. The concentration range of n-6 polyunsaturated fatty acids (PUFAs) remained constant through the accumulation from the diet. The proportion of n-3 PUFAs varied with their level in the diet. The dynamics of alteration of 20:5(n-3) content in Artemia fed on Isochrysis, which is poor in this acid, suggested a limited capacity for elongation and desaturation of 18:3(n-3) to 20:5(n-3). None of the diets provided dietary input of 22:6(n-3). (C) 1998 Elsevier Science Inc. All rights reserved.

C, N and P regeneration by a detritivorous fish, Liza haematocheila T. & S.: effects of temperature, diet and body size

Detritus, as a nutrients reservoir, affects the trophic structure and dynamics of communities and supports a greater diversity of species and longer food chains. Detritivorous fish is an important organism to regenerate the nutrients from sediments. Despite the numerous studies on the nutrients cycle in fish, only a few attempts have been made to quantify the regenerating ability. In the present study, we chose the common detritivorous fish redeye mullet as the research object. Redeye mullet is also a common poly-culture fish in China. Diet, including a commercial diet mostly used in aquaculture and a home-made diet with contents close to detritus, was used and considered as a fixed factor. Temperature was also considered as a fixed factor as much research has shown that temperature has significant effects on fish metabolism. Moreover, body size was regarded as a covariate under analysis of covariance. Three key nutrients, namely carbon, nitrogen and phosphorus, were used to measure the nutrient-regenerating ability of redeye mullet under laboratory conditions. The results showed that the nutrient regeneration in percent of the consumption decreased with increasing temperature. Carbon and nitrogen regeneration of redeye mullet fed on commercial diet was lower than those of the home-made diet group, while the opposite was found for phosphorus. In each group, the amount of regenerated nutrients increased linearly with body size. Fed on the home-made diet, 5-g fish at 25 degrees C can regenerate 210.822 mg C, 37.533 mg N and 0.727 mg P per day.

Effects of diet and body size on phosphorus utilization of Liza haematocheila T. & S.

A 21-d laboratory experiment was conducted to study, the phosphorus (P) utilization of two different diets by redlip mullet Liza haematocheila T. & S. Sand-filtered water in salinity 30 and temperature 25 degrees C was used. Twenty-nine fish individuals were divided into three groups: 11 to group 1 (G1) fed on diet 1, 11 to group 2 (G2) fed on diet 2, and 7 to contrast group. Diet 1 was a commercial feed, more valuable in nutrition than diet 2 that similar to natural detritus. The results show the intake phosphorus (IP) of G1 was significantly higher than that of G2, and both increased linearly with body size at a certain amount of diet. The retention phosphorus (RP) in fish of G1 was lower than G2. The relationship between retention phosphorus and body size was positive and stronger in G2. Significant difference in faecal phosphorus (FP) was found between G1 and G2. Body size significantly impacted the excretion phosphorus (EP) in G1 but G2. The loss of intake phosphor-us in G1 was 10.83-20.27 mg per g fish weight gain, higher than that in G2 for 6.63-9.56. Of the phosphor-us, about 10% was allocated into growth, 50% in faeces, and the rest lost in excretion. The main part of phosphorus was lost in faeces but excretion. The phosphorus budget of the fish could be described as 100IP = 7.40RP + 47.39FP + 36.63EP (Diet 1) or 100IP = 11.93RP + 56.64FP + 21.76EP (Diet 2).

Effects of diet, stocking density, and environmental factors on growth, survival, and metamorphosis of Manila clam Ruditapes philippinarum larvae

A series of experiments was conducted to evaluate the effects of diet, stocking density, and environmental factors on growth, survival, and metamorphosis of Manila clam Ruditapes philippinarum larvae. These experiments examined the following factors: diet (Isochrysts spp., Chlorella spp., and a mixture of Isochrysis spp. and Chlorella spp. [ 1: 1 w/w]), stocking density (5, 10, 15, and 20 larvae ml(-1)), light intensity (un-shaded, partially shaded, and fully shaded), water filtration (unfiltered and sand-filtered), water exchange (50% and 100% once every other day, 25%, 50%, and 100% once daily; 50% and 100% twice daily), and the use of substrate (with and without sand as the substrate). Results indicated that Chlorella spp. could replace 50% of Isochrysis spp. as a food source for the Manila clam larvae without affecting growth, survival, and metamorphosis. Larval growth decreased significantly with increasing stocking density. A density of 5-10 larvae ml(-1) appeared to be optimal for normal growth of Manila clam larvae. Neither diet nor stocking density used in the study had a significant effect on larval survival. Under partially shaded (light intensity = 1000-5000 lx) and fully shaded (light intensity <500 lx) conditions, larval growth was significantly faster than under direct sunlight (un-shaded). A water exchange rate of 50% twice daily provided optimum larval growth. Larvae grew significantly faster in the unfiltered water than in the sand-filtered water. Using sand as the substrate in the culture system significantly depressed the metamorphosis rate. The type and particle size of sand used as the substrate did not significantly affect growth and metamorphosis rates of the larvae. (C) 2005 Published by Elsevier B.V.