Culture Of Diets (Microalgae And Rotifera) And Their Effects On The Growth Of Pseudostellaria

Living food is a kind of high-quality food which has complete ranges of specifications and little pollution to water. Also it’s easy to digest and culture, therefore cultivation with living food shows a clear advantage compared with the traditional cultivation pattern no matter from the nutritional point or the perspective of environmental protection. So it’s crucial to solve the problem of the cultivation of the living food in aquaculture industry. Therefore, the subject was conducted from the perspective of living food’s production and application, selecting the most commonly used Chlorella pyrenoidosa and Brachionus calyciflorus as experimental materials.We tried to explore the ways which can improve the production of living food and summary up a set of completed and efficient cultivation scheme by screening the best medium for C. pyrenoidosa and exploring the effect of y-aminobutyric acid (GABA) on the population growth of B.calyciflorus. Furthermore, we carried on the further research connecting with P. fulvidraco, a famous aquatic product, to provide a set of theoretical basis for the feeding way in larval rearing.1、Screening of the optimal culture medium of Chlorella pyrenoidosaThe quantitative Chlorella pyrenoidesa were respectively put into BBM and BG11 culture mediums and then were cultured at 25℃ with an initial density of 6×104 cells/ml. The experiment was run at 16L:8D and the illumination intensity was 2,000 lx. At the first 5 days, the Chlorella from both of culture medium were in slow growth and thereafter went into the logarithmic phase simultaneously. And then the Chlorella were vigorous growth and the colors of two culture mediums were deepened with the growth of the Chlorella. Although their appearances had no significant differences, the density of the Chlorella in BBM was significantly more than that in BG11(P<0.05). In ninth day, the density of alga in BBM and BG11 culture mediums was respectively 2.44×106 cell/ml and 1.33×106 cell/ml, their growth rate constantly was 0.194/d and 0.169/d,their average generation was 3.572d and 4.101d.The color of the former was dark green while the latter became yellow and thin. The phenomenon indicated that the effect of BBM medium was better than the BG11 medium.2、The influence of γ-aminobutyric acid (GABA) on the population growth of Brachionus calyciflorusUnder the condition of laboratory culture,Brachionus calyciflorus were cultured with EPA culture medium adding different concentrations(0,0.5,5,50,500μg/ml) of GABA. The result showed that each group continued to rise as the growth of the incubation time. Both of them reproduce slowly in early stage and there were no significant difference (P> 0.05).After 10d, The numbers of rotifers in group without GABA increased from the start of 3 to 100 while that with 50 μg/ml of GABA increased from the start of 3 to 179. To an extent, the group with μg/ml of GABA can improve the population growth Significantly (P<0.05) while the others can’t.3, The effectiveness evaluation of the living food on Pelteobagrus fulvidraco20-d feeding experiment was conducted to investigate the influences of different feeds on growth and survival rate of larvae and juvenile of Pelteobagrus fulvidraco in different period. Total 480 fish which were 4 days after hatching were randomly assigned to 24 tanks (20 fish/tank) and fed yolk (yolk group) and rotifers (rotifer group) respectly. In later period, the yolk group were fed yolk, rotifers, Artemia nauplii and rotifers and Artemia nauplii together, as the same as the rotifer group. At the end of the experiment, the comprehensive evaluation of the effects of different combinations of baits was available with the survival rate (SR), specific growth rate (SGR), the final fatness (CF) and increasing weight rate (WGR) as index. The results showed:The SR (90.83%) in fish which were fed rotifers in opening period was higher than that (63.75%) in fish which were fed yolk and the SGR of the former was significantly higher than that of the later. In later period, for yolk group, the SR by feeding yolk, rotifers, Artemia nauplii and rotifers and Artemia nauplii together was 35.00%,48.33%,56.67% and 50.00% respectly and the SGR was 2.48%,3.05%,5.88%,5.22%. Either SR or SGR of fish which were fed rotifers in later period were higher than those of other groups and the rotifer group represents the similar results. When it comes to the whole period of larvae and juvenile oi P.fulvidraco, SR (56.67%) and WGR (3300%) of fish which were fed rotifers in opening period and Artemia nauplii in later period were higher than other groups. A higher SGR (5.00%) was observed in fish fish which were fed rotifers the whole period was higher. The optimal feeding combination to larvae and juvenile of P. fulvidraco was feeding rotifers in the opening period while Artemia nauplii in later period, which can effectively ensure the relatively higher survival rate and faster growth speed.