Comparison of Water Quality Purification and Bacterial Community Structure Between Two Culture Modes of Tiger Shrimp Penaeus monodon
In order to improve the water quality purification capacity in a shrimp culture system and to improve the water environment of shrimp culture,the effects of water quality purification and bacterial community structure were comparatively investigated in two systems,one prepared by brown sugar+Bacillus subtilis(biofloc system)and the other polyurethane packing+nitrifying bacteria(internal circulation system),in the intermediate rearing and culture stage of tiger shrimp Penaeus monodon by high-throughput sequencing to probe into the mechanism of water quality purification from the level of microbiology.The 5-day-old tiger shrimps with body length of(0.5±0.1)cm were cultured in a canvas pond of 1 m3 water body at stocking density of 5 000 ind.·m-3 in the intermediate rearing period for 20 d,and at stocking density of 400 ind.·m-3 in the culture period for 40 d.At the end of the intermediate rearing,the bottom of each canvas pond was spread with sand about 3 cm thick.In the biofloc system,0.5 L of activated Bacillus subtilis was added weekly and brown sugar was daily added at dose of 50％of the daily feeding amount,with 20％of the water was changed biweekly.In the internal circulation system,a polyurethane packing package with a hanging film and a gas stone is placed inside was suspended,and the upper surface was immersed in water.Each system was set with 2 parallel groups.At the end of the experiment,the bacterial samples of water,bottom sand in the biofloc system and the bacterial samples of biofilms,water and bottom sand in the internal circulation system were collected for DNA extraction,and high-throughput sequencing of DNA using the Illumina MiSeq platform.The results showed that there were significantly higher concentrations and greater fluctuation of ammonia nitrogen and nitrite nitrogen in the biofloc system than those in the internal circulation system(P＜0.05).The concentrations of ammonia nitrogen and nitrite nitrogen were shown to be declined in the biofloc system after activated Bacillus subtilis was added and the water was changed.The concentration of nitrate nitrogen was significantly lower and the concentration of chemical oxygen demand was significantly higher in the biofloc system than those in the internal circulation system(P＜0.05),without significant difference in total phosphorus concentration between the two systems(P＞0.05).The analysis of bacterial community structure showed that 25 out of 44 bacterial phyla were shared by all samples,with the dominant bacterial phyla of Proteobacteria and Bacteroidota in the 5 samples,and the relative abundance sum of 58.51％in water in the biofloc system,55.44％in bottom sand in the biofloc system,61.48％in biofilms in the internal circulation system,73.42％in water in the internal circulation system and 65.69％in bottom sand in the internal circulation system.Bacillus,Arenibacter and Lute olibac ter were identified in the biofloc system and Nitrospira,Nitrospina and Pseudoalteromonas were identified in the internal circulation system.These bacteria degraded organic matters,purified water quality and promoted the growth of tiger shrimp.The findings indicated that the purification capacity of biofloc system for ammonia nitrogen and nitrite nitrogen was not as good as that of internal circulation system.There were differences in the composition and relative abundance of bacterial community between the biofloc and internal circulation systems at the level of phylum and genus.
biofloc systeminternal circulation systemPenaeus monodonwater quality purificationbacterial community structure
万方数据
维普
