Culture Biological Characteristics And Haemocytes Immune Function Of Sepiella Maindroni

Sepiella maindroni once was one of the four famous marine products of Zhoushan fishing ground in 1970s.But since 1990's,the nature resource of S. maindroni have been severely damaged because of overfishing.Artificial propagation is an effective way for protecting and resuming the resource of S.maindroni.The contents of this thesis include propagate biology,tolerance of larvae to environmental conditions,growth characteristics,analysis and evaluation of nutrition composition and haemocytes immune function of cultured S.maindroni.This research aimed at offering theory foundation to the aquaculture;laying a foundation to the large-scale production and ecological restoration of S.maindroni resource in Zhoushan fishing ground.The propagate biological characters of this animal has been changed in cultured condition,S.maindroni might spawn twice a year.There were distinct relationship between the growth of ovary and temperature,higher temperature(21.5-23.5℃) accelerate the growth of ovary.The individual fecundity ranged from 565 to 4430 grain(mean=2021 grain) for individuals matured in May,and from 870 to 4354 (mean=2399 grain) for individuals matured in October.It seemed that the individual fecundity increase with the accretion of length or weight,and the individual absolute fecundity and relative fecundity had a linear positive relationship with the length and weight.The grass green polyethylene nodosity net,polyethylene nodosity strands and bamboo chopsticks were tested as the substance for adhering material of spawning, and the former seemed the optimum one.Microscopic observation on the development of embryo of S.maindroni was carried out.The biological zero temperature of embryonic development was 6.53℃, and the effective accumulated one was 397.13℃·d.The optimum temperature,salinity and pH ranged respectively from 18.0 to 24.0℃,20.0 to 30 and 7.0 to 9.0 for the fetation of S.maindroni.The optimum temperature,salinity and pH for survival and growth of S.maindroni larvae were 18.0 to 26.0℃,20.00 to 30.00 and 7.5 to 9.5, respectively.S.maindroni larvae showed high degree of selectivity for alive bait.Rotifer could be used as the starter feed for this tested larvae.With enough feed,the length and weight of S.maindroni increase rapidly during larvae stage.In this period,the growth rate of length and total body weight was 2.86%per day and 8.61%per day, respectively.The relationship of length and body weight seemed exponential.These relationships could be expressed by a curvilinear correlation as follows: W=0.3038L^2.909,R²=0.9698.S.maindroni generally show even growth pattern in this period.During the period from larvae to mature,the growth rate decreased and showed difference in female and male.The relationship between length and day age for female individuals was L_♀=0.1936D-9.416,R2=0.9928,and L_♂=0.161D-6.266, R²=0.9775 for males,those between body weight and day age for female and male were W_♀=4.2967D-289.12,R²=0.9926 and W_♂=3.9772D-264.44,R²=0.9933 respectively.It was recorded that ratioes of body weight to length was W_♀= 3.1256L_♀1.6398,R²=0.9918,in female;and W_♂=2.0268L_♂^1.8115,R²=0.9846 in male.Several biological characters such as length,body width,cuttlebone length and width of S. maindroni were determined.The results showed that there were not simple positive linear relations between length and body width or shell length and width.The relationships were changed following the developing stage and sex.The relationship between length and shell length was linear,the correlation coefficient was higher than 0.99.Thus tshell length could be used for evaluating growth.Biochemical compositions of cultured S.maindroni,wild S.maindroni and S. esculenta were analyzed.The nutritive composition(%,wet) of cultured S.maindroni were that:muscle moisture 75.51±1.92%,protein 16.45±0.62%,fat 1.16±0.068%, ash 3.51±0.30%and sugar 4.27±0.31%.The content of energy was 5.08kJ/g,E/P was 30.88kJ/g.18 common amino acids were found in muscle and 9 of them were essential amino acids for human needs.The total content of amino acids was 15.41% (wet);that of the essential amino acids was 6.16%;the percentage of essential amino acids in total amino acids(E/TA) accounted for 39.97%.The delicious amino acids, i.e.Asp,Glu in total amino acids were 45.42%.The protein nutrient value was high, with the amino acids score(AAS) 82,the first and second limited amino acids were valine and tryptophane.In cultured S.maindroni muscle,the contents of EPA and DHA were also high;the percentage of highly unsaturated fatty acids(HUFA) reached 5.0mg/g.Minerals such as Ca,Mg,Zn,Fe and P in the tested samples seemed plentiful.The result showed that cultured S.maindroni contained higher protein, lower fat,low energy and E/P.Three kinds of histological staining methods were used to study the morphology of haemocytes in cuttlefish S.maindroni.Two types of haemocytes were identified: hyalinocytes and granulocytes.The granulocytes had strong phagocytosis ability to Staphylococcus aureus and Escherichia coli.The haemocytes densities of starved S. maindroni were lower than that of control or sicken.Antibacterial activities of the control group,the starved and the sicken ones were 0.352,0.287 and 0.376 respectively,bacteriolysis of the above groups were 0.225,0.178 and 0.316.Oxygen productions increased with bacteria density,and reached highest when bacteria density was 10⁸cells/ml.