Studys On The Hatching Of Fertilized Eggs And Initial Diets Of Odontobutis Potamophila Larvae And Juveniles

In this paper,Odontobutis potamophila was selected as the research target species.The fertilized eggs of O.potamophila hatching,larvae and juveniles open food were studied by physiological ecology.The effects of different temperatures on the hatching of fertilized eggs and larval activity of O.potamophila were investigated,so that provided some scientific guidance for the large-scale production of fry.The effects of different open food on the growth and survival rate of larvae and the selective feeding of juveniles on different open food to selected ideal open food,so that provided theoretical basis for large-scale breeding of O.potamophila fry.The main research results were as follows:1.Effects of temperature on the hatching of fertilized eggs and larval survival activity of O.potamophilaThe effects of different temperatures?18??20??22??24??26??2 8??30??on the hatching of fertilized eggs and larval activity of O.potamophila were investigated in this study.The results showed that the fertilized eggs of each experimental group could hatch,the incubation period and hatching period of the fertilized eggs shortened along with the rising of the hatching temperature.There was a very significant negative correlation between the incubation period[y?h?]and the hatching temperature[x???],and the equation was:y=1.800x²-112.202x+1948.683,R²=0.996?P<0.01?.The hatching rate showed the change trends of first increase and then decrease along with the rising of the hatching temperature.When the temperature was 26?,the hatching rate was the highest?82.7±2.06%?.Deformity larvae were not observed,and 24 h and 48 h surviving rate of newly-hatched larvae were relatively higher in this experiment.Through the biological zero temperature and the effective accumulated temperature calculation formula,it was concluded that O.potamophila biological zero temperature was 10.6?in embryonicdevelopment,it was concluded that under the condition of different temperatures environment,its range of the change of the effective accumulated temperature was 3815.3±78.40³959.6±80.07?·h.22-30?t emperature range with Q₁₀0 value was the most close to 2,it was 2.0353.but at the temperature of 30?,the fertilized egg hatching rate was 46.4±4.66%,lower than 50%.SAI of the larvae showed the change trends of first increase and then decrease along with the rising of the temperature.When the temperature was24?,SAI of the larvae was the highest?36.91±1.823?.The analysis results showed that the optimum temperature range for the hatch of the fertilized eggs of O.potamophila was 22-28?,the best temperature was 26?and the suitable temperature range for the survival of the larvae was 20-26?,the best temperature was 24?.2.Effects of different initial diets on growth performance and survival rate of O.potamophila larvaeO.potamophila larvae?two days old?were fed with cladocerans,fairy shrimp,formula feed?Miaobaobao?,surimi,yolk,water earthworm,feeding eight days,chose the most suitable initial diets for larvae.The research results showed that there were the fastest growth speed,the optimal growth performance,the highest survival rate of the larvae were fed with fairy shrimp.At the end of the experiment,its average length,average body weight,full-length growth rate,body weight growth rate,specific growth rate and survival rate were 8.609±0.0320 mm,9.17±0.031 mg,27.60±0.476%,171.97±0.930%,12.51±0.042%,96.67±3.335%.It was the most suitable to use the fairy shrimp as the initial diets for O.potamophila larvae;The second were water earthworm and cladocerans,but this kind of exogenous initial diets must be treated with strict disinfection in order to kill possible pathogenic bacteria and parasites;formula feed,surimi and yolk were no significant difference?P>0.05?between the hunger control group,which were not suitable as the initial diets for larvae.3.Selective feeding on different food organisms and feeding rhythm of O.potamophila juvenilesThe feeding selectivity of O.potamophila juveniles?15 days old?to cladocerans,water earthworm,loach larvae,copepods and wigglers and the rhythm to cladocerans was investigated in this study.The results showed O.potamophila juveniles could prey on these five food organisms,and showed obvious feeding selectivity.The feeding rates of O.potamophila juveniles on these five food organisms were 10.4±0.97,10.0±1.18,9.9±1.74,1.6±0.58 and 1.3±0.52 ind/d,respectively.The feeding selecting indexes were 0.2206±0.0369,0.2000±0.0358,0.1922±0.0696,-0.6177±0.1279 and-0.6867±0.1167,respectively.The selective feeding of cladoceras,water earthworms and loach larvae was significantly higher than that of copepods and wigglers?P<0.05?.And there was a significant feeding rhythm in O.potamophila juveniles,and the feeding amount of cladocerans at night was significantly higher than that at day?P<0.05?,which was 27.7±1.51 ind and 20.3±2.16 ind,respectively.The feeding peak of O.potamophila juveniles occurred from 18:00 to 22:00,and the feeding percentage was 24.6%,significantly higher than that of other time stages?P<0.05?.Based on the above research,the purpose of this study was to develop a set of artificial breeding operation procedures for O.potamophila based on the sustainable utilization of wild germplasm resources to guide its actual production.