Effect Of Water Bionutrients On Aquacultural Environment And Growth Performance Of Carassius Aruatus

This experiment was conducted to study the effects of water bionutrients added with bacillus subtilis on several important physicochemical parameters and community structure of aquatic organisms, and then explore what the water bionutrients works on the growth characteristics of carassius aruatus based on the changes of environmental conditions.The research contents and the result are as follows:Testl:Research on the effect of different components of nutrients on the cultural environment. Three types of nutrients represented by inorganic nutrients(IN), micronutrients additives(MA) and water bionutrients(WB) were used in the aquaculture water respectively, a group(NF) without any nutrients was set as control. Collecting the water sample at 7d、21d、 35d and 49d respectively, determining the dynamic change of physicochemical indicators included DO、NH3N、NO2N、TN and TP. Meanwhile, total heterotrophic, bacillus, aeromonas and vibrio were tested by dilution method of plate. The diversity of plankton community in aquaculture water was studied using PCR-DGGE fingerprint atlas technique at 49d. The relations between environmental factors and plankton community would be explained based on the redundancy analysis (RDA). The results show that the content of both TN(P<0.01) and TP in the group IN and WB were improved greatly; The level of DO(P<0.01) had improved prominently in group WB; Significantly higher content of NH3N (P<0.01) and NO2N (P<0.01) were observed in group IN, while a low level of these hazardous substance was found in group MA; Group WB had a more higher diversity of eukaryotic plankton community and effective control of harmful bacteria, while the pathogenic bacteria increased in group IN. So WB has the best effect on sufficient feed and water quality regulation.Test2:Study the effect of nutrients with different organic matter proportion. Set up three groups(B、C、D) that basic nutrients added with organic matter on the proportion of 16%,32% and 48%, a control group(A) without nutrients. Detecting the change of physicochemical indicators and counting the microbe number at 7d、21d and 35d, plankton community was studied by using PCR-DGGE fingerprint atlas technique at 35d, elucidating the relations between environmental factors and plankton community by the redundancy analysis (RDA). Group B fluctuated more fiercer on water quality, NO2N rose sharply (P<0.01) in the middle stage, TN content greatly increased to more than 7.50 mg/L at middle and later culture stage; In Group C, NH3N rose markedly(P<0.01) and DO dropped significantly(P<0.01) in late period; A significantly increase in levels of TN and TP, and the highest diversity of plankton were found in group C; Number of bacillus also higher in trial group, low population of aeromonas were tested in all treatment group, especially significant in group C. Results show that it is unfriendly to water quality control and ecological system maintenance in the group with low organic matter content, which was inclined to cause water quality unstable, while harmful material will rise sharply and easy to trigger the oxygen deficit in the group which organic matter content is exorbitant. Water bionutrients with organic matter proportion of 32% is more appropriate under the conditions of this experiment.Test3:Applying the optimized water bionutrients into the carassius aruatus farming. Groups treated with or without water bionutrients, testing the change of physicochemical parameters and counting the microbe number at 9d、27d and 45d, measuring the growth performance of carassius aruatus including body length, weight-gain, growth rate and fatness. Detecting plankton community and intestinal flora using PCR-DGGE technology, explaining the relations between environmental factors and biocommunity by the redundancy analysis (RDA). Evaluate impact of water bionutrients on growth characteristics of carassius aruatus based on the overall change. Water bionutrients significantly increase TP (P<0.05), TN and DO were higher than control group in the whole test process, NO2N is lower than control group in later period. Total number of heterotrophic bacteria and bacillus is significantly higher in treatment group than control group (P<0.05), there was no significant difference of aeromonas and vibrio; Plankton stripe number and diversity are higher in experimental group than the control group; Intestinal flora structure of crucian carp changes obvious in nutrients group, beneficial bacteria such as lactic acid bacteria(P<0.05) and bifidobacterium(P<0,01) increased significantly, higher number of bacillus(P<0.01) has found while aeromonas (P<0.05) was in lower level, anaerobic bacteria(P<0.01) and enterococcus(P<0.05) had remarkably increase. Water bionutrients obviously improves the carp’s weight-gained rate(P<0.05), special growth rate(P<0.05), fullness and some other relevant growth indexes.Conclusion:Water biolnutrients has obvious effects in the aquatic environment, inorganic nutrients has significant effect in providing nutrients, and micronutrient additive has a important role in reducing the harmful material, the combination can have better effect on growth and water quality regulation; Nutrients in the low organic matter content can lead to unstable of water quality, while with high proportion will increase high oxygen consumption, 32% of the organic matter content can better promote the growth of plankton and improving of environment, and has payed a good role in promoting the growth of crucian carp and improve the intestinal microecology.