| Japanese flounder,Paralichthys olivaceus,was used as material to study in this paper. A series of experiments were conducted to investigate the effects of dissolved oxygen level and stocking density on growth and physiological parameters such as FCE,FI, blood indices,activity of digestive enzyme,activity of SOD,respiratory frequency of juvenile Japanese flounder,based on physiological,immunological and ecological methods.The aim of this work was to furnish basic data for update the new culture techniques and the best design of intensive culture.1 The effects of dissolved oxygen(DO) and stocking density on growth and physiological parameters were investigated in juvenile Japanese flounder, Paralichthys olivaceus(1.26±g) at 20±0.4℃.DO levels and stocking densities were arranged in two modes:5.5±0.5 mg/L(charged by air) and 14±2mg/L(charged by pure O2) with density of 200,400,600,800,1000 ind/m2 respectively.The experiment was lasted 40 days and the lowest survival rate was 94%during the experiment period.①There were significant differences of average body weight after 10 d when fish were cultured under the air charged conduction(P＜0.05) while no significant differences were found under the pure oxygen charged condition.The average body weight of fish held under the pure oxygen charged condition was significantly higher than those of held under the air charged condition(P＜0.05).②FCE declined along with the increase of density,especially under the air charge condition.③No significant differences were found in HIS and dry body weight under two dissolved levels(P＞0.05).④The activity of protease in intestine tissue declined along with the increase of density under two dissolved oxygen levels, especially under the air charged condition.⑤No significant differences were found in activity of SOD in the two dissolved oxygen levels(P＞0.05).⑥Under the pure oxygen charged condition,hemoglobin concentration(Hb) and respiratory frequency were significantly lower than that of fish held under the air charged condition.2 The effects of dissolved oxygen(DO) and stocking density on growth and physiological parameters were investigated in juvenile Japanese flounder Paralichthys olivaceus(14±2.1 g,11.84±0.45 cm) at 20±0.4℃.DO levels and stocking densities were arranged in two modes:5.5±0.5 mg/L(charged by air) with density of 100,200, 300,400 ind/m2 and 14±2 mg/L(charged by pure O2) with density of 200,400,600, 800 ind/m2 respectively.The experiment was lasted 30 days and the lowest survival rate was 94%during the experiment period.①At the density 400 ind/m2,the average body weight was significant lower than the density of 100,200,300 ind/m2 under the air charged condition(P＜0.05).At the density of 400 ind/m2,the weight was significant higher than other density group under the pure oxygen charged condition and SGR was significant higher than that of density under the air charged condition(P＜0.05).②No significant differences were found in FI under two dissolved levels(P＞0.05).③FCE was significantly declined along with the increase of density under the two dissolved oxygen levels and FCE was significant higher under the pure oxygen charged condition than that under the air charged condition(P＜0.05).④There were no significant difference of red blood cell(RBC) count,white blood cell(WBC) count and Hb in the mode charged by air(P＞0.05).In the mode charged by pure O2,there were no significant difference of RBC,WBC(P＞0.05) except for Hb(P＜0.05).At the density of 200 ind/m2,there were no significant difference with RBC and WBC in the two kinds of dissolved oxygen levels except for Hb.While under the density of 400 ind/m2,RBC,WBC and Hb were significantly lower in the pure O2 charged condition compared with the air charged condition(P＜0.05).⑤No significant differences were found in activity of protease in stomach tissue under the two dissolved levels while there were significant differences in activity of protease in intestine tissue.At the same density,the activity of protease in intestine tissue under the pure oxygen charged condition was significant higher than that of under the air charged condition(P＜0.05).⑥No significant differences were found in activity of SOD in the two dissolved oxygen levels(P＞0.05).⑦The density had no effect on the respiratory frequency in the two dissolved levels.The dissolved oxygen level had significant effect on the respiratory frequency (P＜0.05).Overall,the results support the crowding stress of high stocking density can be effectively alleviated in high dissolved oxygen level.3 The relationship between the stocking density and stoking specs was conducted by mathematical method based on the data above as bellow:y = -1.2857x2 - 0.7143x + 391.8 R2 = 0.9938 1.00-7.99 gy = 0.7143x2 - 20.714x + 668 R2 = 0.99 14.00-29.00 g A visual software package written" in.NET was designed for aquaculture plant to determine the optimal stocking density in different stocking modes.
|
PDF Full Text Request