| This paper mainly studied the growth and feeding rhythm,reproduction habits and overwintering characteristics of two bloodsucking leeches,Hirudo nipponica and Poecilobdella manillensis,which are subordinate to hirudinidae.This study preliminarily explored the cultivation techniques of two leeches,aims to provide scientific and effective theory basis for artificial culture of Hirudo nipponica and Poecilobdella manillensis in the future.Research results as follows:By studying the influences of different breeding conditions on the growth and ingestion rules of Hirudo nipponica and of Poecilobdella manillensis,the experimental results revealed that:the specific growth rate of Hirudo nipponica increased at first,and then decreased with the increased of water temperature.When the water temperature was 26?,its growth rate achieved the maximum.There existed a quadratic functional relationship between the specific growth rate of Hirudo nipponica and the water temperature,the regression equation was Y=-0.0165X2+0.8369X-6.8475(R2=0.9908)(p<0.05).The food coefficient rate of Hirudo nipponica firstly decreased and then increased with the water temperature increase.When the temperature was 26?,the food coefficient rate arrived the minimum.The survival rate and specific growth rate of Hirudo nipponica decreased with the increase of breeding density.When the density was 30 leeches/L,specific growth rate of Hirudo nipponica arrived the maximum and was higher than the one of other experimental groups(p<0.05),meanwhile it had no significant difference with the group in density of 60 leeches/L(p>0.05).With the increase of breeding density,the food coefficient rate of Hirudo nipponica increased.The specific growth rate of Hirudo nipponicas decreased with the expanding of feeding cycle,Their linear relationship could be represented by a regression equation Y=-0.0941X+3.8329(R2=0.9927).The total food-intake per Hirudo nipponicas decreased while the feeding cycle grew.The specific growth rate of Poecilobdella manillensis and total food-intake per Poecilobdella manillensis decreased with the expanding of feeding cycle.The specific growth rate of Poecilobdella manillensis decreased as breeding density increased.There existed a linear relationship between the specific growth rate of Poecilobdella manillensis and breeding density,which could be represented by a regression equation Y=-0.0324X+5.3966(R2=0.993)(P<0.05).When feeding ratio was 250%,the specific growth rate of Poecilobdella manillensis arrived the maximum,which had no significant difference with the experimental groups of 200%,150%and 100%(p>0.05),while was significant higher than the one of 50%experimental group(p<0.05).The food coefficient rate of Poecilobdella manillensis decreased firstly and then increased with the increased of feeding ratio,when feeding ratio was 150%,the food coefficient rate of Poecilobdella manillensis arrived the minimum.The results indicated that:the optimum breeding density for the artificial culture of Hirudo nipponicas was 30?120 leeches/L,the optimum feeding cycle was 2?5 days,and Hirudo nipponicas grew better under the water temperature ranged from 22 to 26?.For Poecilobdella manillensis,the optimum breeding density was 2-14 leeches/L,the feeding cycle was 2?4 d,and optimum feeding ratio was 100%?150%.This study explored the characteristics of spawning and hatching on Poecilobdella manillensis under different conditions,and preliminarily observed the reproductive?performance of Hirudo nipponica.The results showed that:spawning rate of Poecilobdella manillensis reached the maximum under room soil temperature(18-24?).The spawning rate of Poecilobdella manillensis decreased as density increased.The weight of Poecilobdella manillensis had significant effects on spawning rate,a trend that spawning rate increased at first and then decreased as the weight increased was observed.When weight ranged from 5 to 15 g,the spawning rate was higher than other experimental groups.When ambient temperature was 26?,hatching rate of Poecilobdella manillensis eggs reached the maximum.more juveniles was hatched as egg weight increased,when the weight of egg ranged from 1.7?2.1 g,The amounts of hatching juvenile arrived the maximum.Compared with Poecilobdella manillensis,Hirudo nipponica had a poor performance on reproductive.The results indicated that:Poecilobdella manillensis could spawn under room soil temperature(18?24?),for Poecilobdella manillensis weighed about 6 g,the optimum density of spawning was 5?10 g·L-1.Poecilobdella manillensis weighed about 5?15 g as parents,a higher spawning rate could be obtained.A higher hatching rate could be observed and more juveniles could be hatched under ambient temperature ranged 22 to 26?,choosing heavier eggs would help to have more juveniles.This study explored the survival rate and weight loss rate of Hirudo nipponica and Poecilobdella manillensis under different soil temperature and density conditions after overwintering.The results showed that:after overwintering,the survival rate of Hirudo nipponica reached highest under room soil temperature(3?8 ?).While the survival rate after overwintering of Poecilobdella manillensis increased as soil temperature increased at first,then decreased as soil temperature continually increased,Which reached the maximum within the range of 15?18?.Survival rate of Hirudo nipponica and Poecilobdella manillensis showed the same trend that all decreased with the increase of density.The results indicate that:in the artificial culture of Hirudo nipponica and Poecilobdella manillensis,Hirudo nipponica could live through the winter safely and effectively under natural condition,while a better survival rate and a lower weight loss rate could be obtained for Poecilobdella manillensis under the temperature environment,in where soil temperature ranged from 15 to 18?.For Hirudo nipponica weighed about 1 g and Poecilobdella manillensis weighed about 7 g,the optimum density during the period of overwintering was 7.5?15 g·L-1. |
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