DIETARY MANGANESE REQUIREMENT OF P. VANNAMEI

M0DUonONManganeseisanessentialelernentfororganismss.TherearernanypublishedreportS0ntheMnrequdritSoritSdrionfishes,indudingrainb0wtrout,channelcatfish,Atianticsalmon,cornmncarp,grasscarp,tilapia,Ctc.Kanamwaetal.(l984)andLiCtal.(l992)reportedtheresultSoftheiraseawhonthernanganeserequdritSofjuvenileP.japonicusandP.chinensiS.Davisandhawrence(l99O)studndthetheofdietaryman-ganeseonP.vannameibydeletionofMnfromthendneralpedinasdri9udrieddiet.ThepresentstudyontheefhaofgtadedleveIs0frnanganeses…     

SELENIUM REQUIREMENT OF SHRIMP PENAEUS CHINENSIS

Penaeus chinensis were reared in fibreglass tanks for the study of their selenium requirements. The shrimp were fed semipurified diets containing graded levels of selenium, and weight gains, activities of glutathione peroxidase (GSH-Px) and selenium contents in muscle and hepatopancreas were determined. Weight gain and GSH-Px activity were the highest when the shrimp were fed diet containing 20 mg/kg selenium; Good linear correlation was found between GSH-Px activities and selenium contents in the diets, and the number of healthy shrimp. The experiment showed that 20 mg/kg selenium in the diet is optimal for the shrimp and that GSH-Px activity can be an important biochemical index of the selenium nutrition status of the animal.     

DIETARY PHOSPHORUS REQUIREMENT OF YOUNG ABALONE, HALIOTIS DISCUS HANNAI INO

An experiment was performed to determine the dietary phosphorus requirement of the young abalone,Haliotis discus hannai. Five semi-purified diets were formulated to provide a series of graded levels of dietary total phosphorus (0.23%–1.98) from monobasic potassium phosphate (KH2P04). The brown alga,Laminaria japonica, was used as a control diet. Similar size abalone were distributed in a single-pass, flow-through system using a completely randomized design with six treatments and three replicates each treatment. The abalone were hand-fed to satiation with appropriate diets in excess, once daily at 17:00. The feeding trial was run for 120-d. Survival rate and soft-body to shell ratio (SB/S) were constantly maintained regardless of dietary treatment. However, the weight gain rate (WGR), daily increment in shell length (DISL), muscle RNA to DNA ratio (RNA/DNA), carcass levels of lipid and protein, soft-body alkaline phosphatase (SBAKP), and phosphorus concentrations of whole body (WB) and soft body (SB) were significantly (ANOVA, P<0.05) affected by the dietary phosphorus level. The dietary phosphorus requirements of the abalone were evaluated from the WGR, DISL, and RNA/DNA ratio respectively, by using second-order polynomial regression analysis. Based on these criteria, about 1.0%–1.2% total dietary phosphorus, i.e. 0.9%–1.1% dietary available phosphorus is recommended for the maximum growth of the abalone. Project 39670572 supported by the NSFC.     

Effects of Different Diets on the Dietary Attractability and Selectivity of Chinese Shrimp,Fenneropenaeus chinensis

1Introduction Shrimp and crab have sensitive chemoreceptors andthey are chemosensitive to substances dissolved in wa-ter(Chen and Sun,1992;Chen,1995,1996a,1996b).This capability is crucial to their feeding behav-ior?.It has been found in shrimp and crab that alarge number of chemical substances and some con-tents distilled from their diets can activate their feed-ing responses.These kinds of chemical substances anddistilled content are defined as'food attractant'or'feeding stimulant'(Fuzessa…     

Dietary leucine requirement for juvenile large yellow croaker <Emphasis Type="Italic">Pseudosciaena crocea</Emphasis> (Richardson, 1846)

Dietary leucine requirement for juvenile large yellow croaker, Pseudosciaena crocea Richardson 1846 (initial body weight 6.0 g ± 0.1 g) was determined using dose-response method. Six isonitogenous (crude protein 43%) and isoenergetic (19 kJ g⁻¹) practical diets containing six levels of leucine (Diets 1–6) ranging from 1.23% to 4.80% (dry matter) were made at about 0.7% increment of leucine. Equal amino acid nitrogen was maintained by replacing leucine with glutamic acid. Triplicate groups of 60 individuals were fed to apparent satiation by hand twice daily (05:00 and 17:30). The water temperature was 26–32°C, salinity 26–30 and dissolved oxygen approximately 7 mg L⁻¹ during the experimental period. Final weight (FW) of large yellow croaker initially increased with increasing level of dietary leucine but then decreased at further higher level of leucine. The highest FW was obtained in fish fed diet with 3.30% Leucine (Diet 4). FW of fish fed the diet with 4.80% Leucine (Diet 6) was significantly lower than those fed Diet 4. However, no significant differences were observed between the other dietary treatments. Feed efficiency (FE) and whole body composition were independent of dietary leucine contents (P > 0.05). The results indicated that leucine was essential for growth of juvenile large yellow croaker. On the basis of FW, the optimum dietary leucine requirement for juvenile large yellow croaker was estimated to be 2.92% of dry matter (6.79% of dietary protein).     

电子商务发展、人才需求趋势及人才培养模式分析

电子商务在跌宕起伏中保持发展，电子商务的内涵日益丰富，电子商务人才需求问题日显突出。根据目前实际中表现出对电子商务人才需求的现象，分析电子商务人才分布和类型，提出电子商务人才培养方向、培养模式和课程调整的设想或建议。     

Study of Panjin wetlands along Bohai coast (II): Ecological water requirement of Shuangtaizi estuarine wetland

Shuangtaizi estuarine wetland along the Bohai Sea coast, the biggest bulrush wetland in the world, has been listed in ‘The Record of Important International Wetland Conservation District’. Taking the year of 2 000 as an example, the minimum, the most suitable and the maximum ecological water requirement of Shuangtaizi estuarine wetland are calculated in this paper based on both ecological theory and Geological Information System technology. In addition, the remote sensing technique is adopted in the data acquisition process. Moreover, the total water requirement and the unit area water requirement for different wetland types are obtained. The result is very important for water resources planning, ecological conservation and regional agriculture structure adjustment in Shuangtaizi. Meanwhile, this study can serve as a useful example for calculating the ecological water requirement in other similar estuarine wetlands.     

Assessment of nitrogen maintenance requirement in juvenile Black Porgy Acanthopagrus schlegeli

Nitrogen balance method and nitrogen-free diet were used in this study to determine nitrogen maintenance requirement (NM) and nitrogen maintenance requirement per unit metabolism body weight (NM’) of black porgy Acanthopagrus schlegeli. Fish with body weight (BW) of 50, 80, 120, 160 and 200 g were fed by the diets containing three graded levels of crude protein (380, 420 and 460 g/kg). The results from nitrogen balance experiment showed that the amount of nitrogen deposition varied from 0.15 to 0.31 mg/g BW...     

Effects of Different Diets on the Dietary Attractability and Selectivity of Chinese Shrimp, Fenneropenaeus chinensis

Attractabilities of different diets and dietary selectivity of Chinese shrimp, Fenneropenaeus chinensis were studied through behavior observation and feeding experiment, respectively. The five diets used in the experiment are: Fish Flesh (FF), Shrimp Flesh (SF), Clam Foot (CF), Polychaete Worm (PW), and Formulated Diet (FD). No significant differences of attractability exist between any two different diets when every two natural diets or all five diets are provided simultaneously. On the other hand, significant differences of attractability exist between FD and every single natural diet when they are provided simultaneously. Results of behavioral observation indicate that natural diets are more attractive than FD. In feeding experiment, Chinese shrimp has distinct selectivity on different diets. It positively selects CF and PW, negatively selects FF and SF, and excludes FD absolutely. The results of the present studies indicate that the dietary selectivity of shrimp was based not only on the attractabilities of the diets, but also on the responses such as growth and food conversion.     

Simultaneous determination of iron and manganese in water using artificial neural network catalytic spectrophotometric method

A new analytical method using Back-Propagation (BP) artificial neural network and kinetic spectrophotometry for simultaneous determination of iron and magnesium in tap water, the Yellow River water and seawater is established. By conditional experiments, the optimum analytical conditions and parameters are obtained. Levenberg-Marquart (L-M) algorithm is used for calculation in BP neural network. The topological structure of three-layer BP ANN network architecture is chosen as 15-16-2 (nodes). The initial value of gradient coefficient μ is fixed at 0.001 and the increase factor and reduction factor of μ take the default values of the system. The data are processed by computers with our own programs written in MATLAB 7.0. The relative standard deviation of the calculated results for iron and manganese is 2.30% and 2.67% respectively. The results of standard addition method show that for the tap water, the recoveries of iron and manganese are in the ranges of 98.0%-104.3% and 96.5%-104.5%, and the RSD is in the range of 0.23%-0.98%; for the Yellow River water (Lijin district of Shandong Province), the recoveries of iron and manganese are in the ranges of 96.0%-101.0% and 98.7%-104.2%, and the RSD is in the range of 0.13%-2.52%; for the seawater in Qingdao offshore, the recoveries of iron and manganese are in the ranges of 95.3%-104.8% and 95.3%-104.7%, and the RSD is in the range of 0.14%-2.66%. It is found that 21 common cations and anions do not interfere with the determination of iron and manganese under the optimum experimental conditions. This method exhibits good reproducibility and high accuracy in the determination of iron and manganese and can be used for the simultaneous determination of iron and manganese in tap water and natural water. By using the established ANN- catalytic spectrophotometric method, the iron and manganese concentrations of the surface seawater at 11 sites in Qingdao offshore are determined and the level distribution maps of iron and manganese are drawn.     

COMPARATIVE STUDIES ON THE LARVAL DEVELOPMENT OF THE PENAEID SHRIMPS,PENAEUS CHINENSIS,P.MERGUIENSIS AND P.PENICILLATUS

The morphology of larval and 1st postlarval stages of Penaeus penicillatus are described.Results from comparative studies on larval development of P.penicillatus,P.merguiensis and P.chinensis are as fol-lows: These three species could not be identified during their naupliar stages. In the 1st protozoea,the antennule L1/L2 value is 1.7—2.0 in P.merguiensis,but lessthan 1.7 in P.chinensis and P.penicillatus;in the 2nd protozoea,the supra-orbital spine in P.chinensis isnot bifurcated,while those of P.merguiensis and P.penicillatus are bifurcated;in the 3rd protozoea,thereis a minute(or no)dorso-median spine on the posterior margin of the 1st and 2nd abdominal somite in P.chinensis,but they are prominent in P.merguiensis and P.penicillatus.In the mysis and 1st postlarvalstages,P.chinensis differs from P.merguiensis and P.penicillatus in having 9(8 in the other 2 species)longsetae on the exopod of pereopods 1—3;additionally,one dorsal tooth appears on the rostrum of P.chinensis in the 2nd mysis and that o     

Comparative studies on the larval development of the penaeid shrimps,Penaeus Chinensis,P. merguiensis andP. penicillatus

The morphology of larval and 1st postlarval stages ofPenaeus penicillatus are described. Results from comparative studies on larval development ofP. penicillatus, P. merguiensis andP. chinensis are as follows: These three species could not be identified during their naupliar stages. In the 1st protozoea, the antennule L1/L2 value is 1.7–2.0 inP. merguiensis, but less than 1.7 inP. chinensis andP. penicillatus; in the 2nd protozoea, the supra-orbital spine inP. chinensis is not bifurcated, while those ofP. merguiensis andP. penicillatus are bifurcated; in the 3rd protozoea, there is a minute (or no) dorso-median spine on the posterior margin of the 1st and 2nd abdominal somite inP. chinensis, but they are prominent inP. merguiensis andP. penicillatus. In the mysis and 1st postlarval stages,P. chinensis differs fromP. merguiensis andP. penicillatus in having 9 (8 in the other 2 species) long setae on the exopod of pereopods 1–3; additionally, one dorsal tooth appears on the rostrum ofP. chinensis in the 2nd mysis and that of the other 2 species in the 3rd mysis;P. chinensis has 2 (mostly) or 1 dorsal tooth on the rostrum in the 3rd mysis and 2–3 in the 1st postlarva, whileP. penicillatus andP. merguiensis have only 1 in the 3rd mysis and 1st postlarva. Comparative studies on larval development showedP. penicillatus has closer affinity withP. merguiensis than withP. chinensis. Contribution No. 2218 from the Institute of Oceanology, Chinese Academy of Sciences     

Studies on the phosphorus requirement and proper calcium/phosphorus ratio in the diet of the black sea bream (Sparus macrocephalus)

An expriment on the phosphorus requirement and the proper Ca/P ratio in the diet of the black sea bream using the phosphorus gradient method (with casein as basic diet, sodium dihydrogen phosphate as source of phosphorus, and calcium lactate as source of calcium) showed that growth was greatly affected by the diet's phosphorus content and Ca/P ratio. Inadequate phosphorus in the diet resulted in slow growth and poor food conversion ratio (FCR). Analyses of the fish body showed it contained a high level of lipid but a low level of moisture, ash, calcium and phosphorus. The optimal values of phosphorus and Ca/P ratio in the black sea bream diet are 0.68% and 1∶2 respectively. Phosphorus in excess of this optimum value resulted in slow growth or even death. The results of this experiment clearly indicated that phosphorus is the principal mineral additive affecting black sea bream growth. Contribution No. 1972 from the Institute of Oceanology, Academia Sinica.     

Measurement of trace manganese (II) by the catalytic kinetic spectrophotometric method

A new kinetic spectrophotometric method is developed for the measurement of manganese (II) in water. The method is based on the catalytic effect of manganese (II) with the oxidation of weak acid brilliant blue dye (RAWL) by KIO₄ using the Nitrilo triacetic acid (NTA) as an activation reagent. The optimum conditions obtained are 40 mgL⁻¹ RAWL, 1×10⁻⁴molL⁻¹ KIO₄, 2×10⁻⁴ molL⁻¹ Nitrilo triacetic acid (NTA), pH = 5.8, the reaction time of 3.00 min and the temperature of 20.0 °C. Under the optimum conditions, the proposed method allows the measurement of manganese (II) in a range of 0–50.0 ng mL⁻¹ and with a detection limit of down to 0.158 ng mL⁻¹. The recovery efficiency in measuring the standard manganese (II) solution is in a range of 98.5%–102%, and the RSD is in a range of 0.76%–1.25%. The new method has been successfully applied to the measurement of manganese (II) in both fresh water and seawater samples with satisfying results. Moreover, few cations and anions interfere with the measurement of manganese (II). Compared with other kinetic catalytic methods and instrumental methods, the proposed method shows fairly good selectivity and sensitivity, low cost, cheapness, low detection limit and rapidity. It can be applied on boats easily.     

点带石斑鱼幼鱼配合饲料的适宜能量蛋白比

以鱼粉和酪蛋白为蛋白源,添加鱼油、豆油、α-马铃薯淀粉、纤维素以及适量的维生素和矿物质配制成实验饲料,蛋白质质量分数设置41%、47%、53%3个水平,能量设置12 561、14 655、16 748 kJ/kg 3个水平,饲养点带石斑鱼幼鱼59 d后,以增重率、蛋白质效率、饲料系数为评价指标,分析不同能量蛋白比的饲料对点带石斑鱼体内消化酶活性的影响。结果表明:当能量蛋白比分别为31.30、33.50、32.26 kJ/g时,点带石斑鱼增重率、蛋白质效率达到极大值,饲料系数达到极小值;能量蛋白比在31.62～35.54 kJ/g范围内,胃、肠道的蛋白酶、淀粉酶、脂肪酶活性较强。点带石斑鱼幼鱼配合饲料中合适的能量蛋白比为31.62～33.50 kJ/g。     

不同饲料蛋白水平下L-肉碱对新吉富品系尼罗罗非鱼生长和饲料利用的影响

研究了三个蛋白水平(22%、25%、28%)和五个L-肉碱水平(0、200、400、600、800mg/kg)下尼罗罗非鱼生长和饲料利用率。结果表明,随着饲料中蛋白水平的提高,罗非鱼幼鱼的终体重、增重率(WGR)和特定生长率(SGR)呈上升趋势,而饲料系数(FCR)和蛋白质效率(PER)均随饲料蛋白水平的升高而显著下降(P<0.05);同等蛋白水平下,终体重、WGR和SGR均在L-肉碱添加量为200mg/kg时最高,不添加L-肉碱组最小;在添加400mg/kgL-肉碱时FCR最小,而PER最大,与不添加L-肉碱组比较,差异均显著(P<0.05)。说明饲料中蛋白含量和L-肉碱添加量能显著影响罗非鱼幼鱼的生长和饲料利用,而外源性L-肉碱可明显促进罗非鱼生长,提高饲料转化效率。     

Effects of Dietary Protein Level on Growth and Utilization of Protein and Energy by Juvenile Mangrove Red Snapper (Lutjanus argentimaculatus )

1Introduction The mangrove red snapper,Lutjanus argentimacu-latus(Forsskal,1775)is a carnivorous,warm-watereuryhaline fish that is considerably cultured in South-east Asia,Southern China and the Middle East(Le-ung et al.,1999;Estudillo et at.,2000;Ng et al.,2000;Catacutan et al.,2001).In Pakistan,it isknown for its good quality meat and also for its highconsumption rate.Although it fetches a premiumprice at local markets(Anonymous,2002),the in-creasing demand has generated interest towar…     

Advances in the Study on Nutrient Requirements of Grouper (Epinephelus sp. ): a Review

The paper reviews the recent advances in studying grouper nutrition requirement for the development of cost-effective and environmentally friendly artificial diets. It consists of seven parts: protein and amino acid, lipid and essential fatty acid, carbohydrate, vitamin, mineral, alternative protein source, broodstock and larval nutrition. The review provides some basic information for further investigation of nutrient requirements of groupers.     

Assessment of nitrogen maintenance requirement in juvenile Black Porgy <Emphasis Type="Italic">Acanthopagrus schlegeli</Emphasis>

Nitrogen balance method and nitrogen-free diet were used in this study to determine nitrogen maintenance requirement (NM) and nitrogen maintenance requirement per unit metabolism body weight (NM′) of black porgy Acanthopagrus schlegeli. Fish with body weight (BW) of 50, 80, 120, 160 and 200 g were fed by the diets containing three graded levels of crude protein (380, 420 and 460 g/kg). The results from nitrogen balance experiment showed that the amount of nitrogen deposition varied from 0.15 to 0.31 mg/g BW per day, accounting for 12.2% to 21.1% of nitrogen intake. The amount of fecal nitrogen excretion varied from 0.21 to 0.32 mg/g BW per day, accounting for 16.3% to 21.6% of nitrogen intake. The endogenous nitrogen excretion, a main part of nitrogen consumption varied from 0.79 to 0.97 mg/g BW per day, accounting for 63.3 % to 68.0% of nitrogen intake. Positive correlation was found between NM and body weight, while a negative correlation was found between NM of unit body weight and the growth duration. No significant differences (p>0.05) were found in NM′ among different growth stages. The average of NM′ was 0.485 7mg/g per day. The results from nitrogen-free diet experiment showed that a negative correlation between NM and feed intake of nitrogen-free diet. NM increased with the decrease of feed intake of fish. The average of NM was 0.482 9 mg/g BW per day that was close to 0.483 8 mg/g BW obtained from fish with 120 g BW in nitrogen balance experiment. The nitrogen balance method is recommended to be a better method for determining NM in consideration of fish stress and result stability. This study also provides a calculated result of the protein content in diets, which is necessary for maintaining fish body protein at different growth stages. The calculation was based on the amount of nitrogen required for maintaining body protein per kg BW. Supported by Scientific Research Project Grant (No.2004C100059) from the city government of Ningbo, China.