| In this thesis a study have been physiologically and biochemically made on inland controllable ecological intensive culture mode of Pseudosciaena crocea as well as on the influence and characterization of ecological factors such as temperature?salinity?feed and water quality in ecology and physiology.A pilot scale experiment was carried out.The main conclusions are as follows:(1)In laboratory the tolerance water temperature of juvenile Pseudosciaena crocea(body weight was 38.42 ±2.40g)was studied under controlled temperature conditions.The result indicated that the high and low lethal temperature of juvenile Pseudosciaena crocea was 37? and 8? respectively.Biochemical analysis findings of serum showed that the mutation of temperature caused damage to the liver and other organs of juvenile Pseudosciaena crocea,and made changes to the serum enzyme and blood lipid.(2)Juvenile Pseudosciaena crocea(body weight was 20.78±2.13g)were reared in five temperature groups at 22,24,26,28 and 30? for 40d in a controllably ecological culture mode.The results indicated that different temperatures had significant effects on the growth of juvenile Pseudosciaena crocea(P<0.05).The optimum temperature for the growth of juvenile Pseudosciaena crocea was 28?.In this temperature,the specific growth rate(1.65±0.26%·d-1)?food efficiency(67.67±4.29%)and activity of digestive enzyme were high and the water quality was much more favorable for regulation.(3)Larval Pseudosciaena crocea were reared at three salinities 6,16,and 26 for 95d in a controllably ecological culture mode.The gill structure were examined by light and transmission electron microscopy.The results indicated that with the increasing of salinity,the juvenile Pseudosciaena crocea increased the number and size of chloride cells,the number of mitochondria also increased,and the tubular network get more compact.(4)Juvenile Pseudosciaena crocea(body weight was 13.36±0.33g)were reared at five salinities 6,12,18,24 and 30 for 40d in a controllably ecological culture mode.The results suggested that different salinities had significant effects on the growth(P<0.05).The juvenile Pseudosciaena crocea had the highest specific growth rate(1.83 ±0.05%·d-1)and food efficiency(61.14 ± 1.34%)in salinity 12.The Na+/Ka+-ATPase activity was small in this salinity,the activity of gill and kidney was 2.546 ± 0.067 ? molPi/(mgpr · h)and 2.188 ±0.086 ? molPi/(mgpr · h)respectively.Different salinities had not significant effects on water quality(P>0.05).(5)The combined effect of temperature and salinity on the growth of juvenile Psedosciaena crocea(body weight was 15.82 ± 0.90g)was studied,too,in the same mode.The uniformity design was adopted in the experiment.There came the results that the juvenile Pseudosciaena crocea had the highest specific growth rate and food efficiency when the temperature was 30.2?30.45? and the salinity was 16.37?24.35.(6)It was in the same mode that juveniles Pseudosciaena crocea(body weight was 36.71 ± 1.51g)were feeding with fresh fish?expanded feed and soft pellet feed for 40d.The results indicated that feeding with fresh fish was not a good choice in this controllably ecological culture mode since the water conditions were more inclined to be polluted.The fish had a slow growth rate and low survival rate.The expanded feed was most suitable.With expanded feed,the specific growth rate was the highest(2.06 ±0.11%·d-1)and food efficiency(68.95 ± 1.08%),and the water conditions were the most faborable.(7)Six feeds were mixed with astaxanthin to investigate the effect of astaxanthin on growth and body color.Five different weight of 0,20,40,80,160 and 320mg/kg were prepared,and fed juvenile Pseudosciaena crocea(body weight was 31.92±1.63g)for 40d.The results indicated that there was no remarkable effect on the growth(P>0.05),but had significant effect on pigmentation,the optimal astaxanthin amount was 80mg/kg.(8)An experiment was also made on the acute toxic effects of ammonia and nitrite at the temperature of 23 ± 1 °C,salinity 20,pH7.4?7.5,and dissolved oxygen more than 5.0 mg · L-1.The results showed that the half lethal concentrations(LC50)and the safe concentrations(Cs)of ammonia were 37.34?20.97?17.59?12.45 and 1.25 mg ·L-1 in the fish with body weight 31.54±0.99g at 24?48?72 and 96h respectively,corresponding non-ionic ammonia concentrations were 0.46?0.25?0.21?0.15 and 0.015 mg ·L-1,the half lethal concentrations(LC50)and the safe concentrations(Cs)of nitrite on juvenile Pseudosciaena crocea were 137.45?94.02?72.81?50.06 and 5.01 mg· L-1.The activity of serum enzyme and blood lipid concentration of juvenile Pseudosciaena crocea was changed after exposure to LC50 of ammonia and nitrite.(9)Some juvenile Pseudosciaena crocea(body weight was 7.81±0.38g)were reared in nature marine water and others in artificial marine water for 60d.The results indicated that there were not significant effects on specific growth rate?food efficiency?condition factors and survival rates,nor significant effects on most of the amino acid and fatty acid content(P>0.05).But we found some significant effects on a handful of amino acid and fatty acid content(P<0.05).(10)A pilot scale experiment of inland controllably ecological culture of juvenile Pseudosciaena crocea was carried out.In the two phases the juvenile Pseudosciaena grew fast with no water changed and no drug used.The juvenile Pseudosciaena crocea had significant difference in meat quality used ecological culture mode and traditional mode(P<0.05).In the studied of plankton,the result indicated that the diversity of phytoplankton was good in the early stage,the diversity index and evenness index decreased in the later stage.The diversity of phytoplankton was poor in the end of the experiment.There was little change in the diversity index and evenness index of zooplankton.The result proved that this controllably ecological culture mode can be applied in intensive aquaculture of Pseudosciaena crocea. |
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