Application Of Micro-seaweed Powder Particles In The Culture Of Cladocerans

Cladoceran is known as daphnia and bloodworms, belonging to arthropoda, crustaceans, gillfoot subclass, Cladocera.widely distributed in freshwater, seawater and inland brackish water.Food choices was always been a very important factor in cladoceran’s growthing and reproductive.The traditional food generally is unicellular algae, yeast, Banta fluid and so on, it’s need more time.The study, seaweed powder as cladoceran new bait has not been reported.This study was conducted from June2012to September2013, to study the mechanism ofcladocera use of the seaweed powder; explore the impacts of micro-particles of seaweed powderon cladocera’s population dynamics and reproductive; analysis and comparison the fatty acids ofwater flea Daphnia pulex cultured in micro-particles seaweed powder, Chlorella sp., bread yeastand liquid, were determined by GC/MC; analysis the ability of daphnia pulex feeding on seaweedpowder in the environmental of copper or cadmium; examined SOD and POD enzyme activity ofdaphnia pulex and moina mongolica feed on seaweed powder. The results as follows:(1) The research indicated that micro-seaweed powder particles can be degraded naturally inthe cultivation process of cladocerans. The degradation is mainly caused by microorganisms in theenvironment, and microorganisms in water play the main part. At72h, its ability of degrade is threetimes than the microorganisms of air and algal, and two times than the microorganisms of daphnia.(2) To study and found, cladocera used of seaweed powder which was been enzymaticed andthe size less than25um, not was the simple sugars and other nutrients.(3) In this study, we conducted the change in population and reproductive of Daphnia pulexand Moina mongolica Daday caused by seaweed powder and enzymatic liquid of seaweed powder.we find that Daphnia pulex population density reached the maximum of5.5ind/ml under thefeeding by Laver Powder directly when the concentration is0.15mg/ml, but there is no significantdifference（p＞0.05）. The highest reproduction ability of Daphnia pulex achieved72indin theconcentration of1.5mg/ml group, but the highest reproduction ability is slightly lower than that incontrol group; the reproduction ability of Moina mongolica Daday is best in enzymatic hydrolysatewith the concentration of0.75%group, but significantly lower than that in control group (p <0.05), and only less than half of the control group. So I think seaweed powder can be used as a suitablebait for Daphnia pulex, but not for Mongolia Moina.(4) The compositions of fatty acids of water flea Daphnia pulex cultured in seaweed powder,Chlorella sp., bread yeast and liquid, were determined by GC/MC. The total lipid level was39.80mg/g、60.10mg/g、44.60mg/g and52.30mg/g respectively. Fourteen fatty acids werefound, in which there were8saturated fatty acids (SFA),2monounsaturated fatty acids(MUFA), and4polyunsaturated fatty acids (PUFA). The PUFA of seaweed powder wassignificantly higher than that of yeast Banta group (P <0.05), more than1/3total fatty acids. Thewater flea fed the liquid of Banta had52.45%(P <0.05) of SFA while the Daphnia fed breadyeast had55.73%(P <0.05) of MUFA. The seaweed powder group EPA up to22.67%(P <0.05), AA up to9.02%(P <0.05) is1.6times and4.5times of Chlorella group. And the actualamount of EPA and AA was significantly higher than chlorella group (P <0.05), reached9.02mg/g and3.59mg/g.It is proof that of daphnia pulex in seaweed powder has higher fattynutrition.(5) We also analyzed the half death concentration of Daphnia pulex in Cu2+and Cd2+withdifferent time. The results showed that in Cu2+toxicity experiment, within24,48,72and96hours,the half death concentration of Laver Powder are293.3,192.4,127.1and90.5ug/l respectively;However, in Cd2+toxicity experiment, within24,48,72and96hours, the half death concentrationof Laver Powder are432.1,191.4,135.7,79.8ug/l respectively; we found Daphnia pulex offspringamount decreased gradually with the Cu2+and Cd2+increasing. When Cu2+reached1.0ug/l, thesurvival period, total amount of litter, number births of litter and other indicators decreasedsignificantly (p <0.05). When Cd2+reached5ug/l, there has the same result. The tolerance ofDaphnia pulex for Cu2+and Cd2+was less than the control group,so Daphnia pulex in seaweedpowder will more sensitive on detection Cu2+and Cd2+.(6) The detection of SOD and POD enzyme activity of daphnia pulex and moinamongolica were cultured in seaweed powder. It found that SOD activity under seaweedpowder was significantly higher than chlorella fed (p <0.05). The SOD activity of daphniapulex and moina mongolica on seaweed powder with the time of starvation extension wasincreasing. However, the POD activity was different, daphnia pulex with the starvation timeextension was fall and moina mongolica had no significant change. It considered that theantioxidant capacity on Daphnia pulex in seaweed powder is stronger than Chlorella.Based on the lots of research results, it can be considered that micro-particles seaweedpowder as a new bait could completely replace the traditional bait on daphnia pulex, but withthe moina mongolica, seaweed powder can not serve as suitable bait.