| Antarctic Krill (Euphausia superba) is living in the waters surroundingAntarctica, perennial surviving at low temperature.It is the dominantspecies in Antarctic waters, and is also very important as many otheranimals’food in the Antarctic biosphere. With currently increasinginvestment of development and application of Antarctic krill resourcesin China, more and more attention is put on the way how we canefficiently use Antarctic krill resources. The main application of Antarctickrill abroad is as the feed protein sources and the krill oil as a health food.In order to apply the Antarctic krill as fish feed, we investigated theeffects of shelled Antarctic krill meat and the effects of dietarysupplementation with Antarctic krill polypeptide (KP) without flouride ongrowth, physioloical and biochemical index of zebrafish (Danio rerio).In the first part of this study, the effects of the growth indicators ofzebrafish which fed the feed added the shelled Antarctic krill meat as theprotein source which instead of fish meal was investigated. The fish weredivided into3groups by appended different level shelled Antarctic krillmeat, which containing11.5%、23%、34.5%，in the diets respectively.Aftercontinuous feeding zebrafish for56days, the situation of growth was observed. The data of growth was recorded according to the plan, thegrowth index of zebrafish was calculatede, such as length gain rate,weight gain rate(WGR),special growth rate(SGR),and concluded the foodconversion rate(FR),feed efficiency,feed coefficient.The results indicatedthat length gain rate,WGR,SGR were lower than the control groupsignificantly（P<0.05）.With the extension of feeding time, the resultsshowed that the effect of female fish’s fertility in experimental groupwas negtive. And the results also showed that Antarctic krill meal for fishgrowth performance was no clear or significant.With the increasing ofadding shelled Antarctic krill meat, this phenomenon was even moresignificant. At the same time, there maybe also have a disadvantage tofish breeding.In the second part of this study,the effects of dietary supplementationwith Antarctic krill polypeptide (KP) without flouride on growth,physioloical and biochemical index of zebrafish were evaluated.The fishwere divided into3groups by appended different level polypeptidewithout fluoride fromAntarctic krill, which containing1%、2.5%、5%in thediets respectively.Continuous fed zebrafish for56days, then the situationof growth was observed, After fed for56days, the growth index,physioloical and biochemical index of zebrafish, such as length gain rate,WGR,SGR,visceral weight ratio,condition factor, reproductive capacity,erythrocyte and leukocyte count,hemoglobin contents,bone and muscle fluoride content,Superoxide dismutase(SOD) in plasma and erythrocytewere detected. Meanwhile,the FR,feed efficiency,feed coefficient,proteinefficiency rate(PER) were also tested.The result indicated that theexperimental group added KP were higher than the control group ongrowth and physiological indexes. The results indicated that FR,PER andfeed efficiency were best(3.14,31.77%,0.97%) in the group added1%KP.The WGR was best(188.17±1.67%) in the group added5%KP.Theresults of spesial weight ratio were same among the experimental groupand higher than control group(P<0.05).Fatness contrast between thecontrol group and the experimental group did not show regularity.Theresult of visceral weight ratio showed all experimental group except KPadded1%were higher than control group and was significant(P<0.05).The result also showed that the KP could effectively improve the growthperformance of zebrafish and promoted the non-specific immunity ofzebrafish. Fluorine content increased in muscle tissue was not verysignificant,the most was1.61mg/kg and not higher than the national foodstandard（s2mg/kg）. Bone fluoride content in the experimental group washighter than the control group(213.32mg/kg).The more KP added,thehighter result was.But there had no effects on the muscle fluoride content.In the third part of this study,the effects of dietary supplementationwith KP without flouride on fecundity of zebrafish were evaluatedmainly.After fed for56days, some female fish in each group were selected and weighted. The ovaries were removed and weighted, then thenumber of eggs in the ovaries were counted of all. Then the fertilityindexes which including absolute fecundity, relative fecundity andgonadosomatic index were tested.The result indicated that the KP mighthave disadvantageous for breeding. All index of the experiment groupwere lower than the control group (P<0.05).And this phenomenon wassignificant with fed by KP without flouride.This result showed that thefeed which added KP should be cautious for broodstock. |
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