| 【Objective】The study was conducted to explore the mechanism of the action of the regional microbiological curing agent in improving the ecological environment in aquaculture.【Method】The simulated pond ecological
environment was established in 4 aquarium tanks, in which the mud and water were collected from a healthy pond in
Nansha town of Guangzhou City (Group 1 and 3), an unhealthy pond from Nansha Town (Group 2), and an unhealthy pond in
Qingyuan City. 3 Aristichthys nobilis, 2 Oreochromis mossambicus and 2 Pterygoplichthys multiradiatus were cultured in each tank and the scientific feeding management was applied to observe the effects of conserving stuff on water quality factors,
phytoplankton, protozoa and fish survival rateby using local pond microorganism in Nansha and Qingyuan and pond microbiological curing agent (conserving stuff) made from agricultural sub-products regularly.【Result】With the use of conserving
stuff, the ammonia nitrogen was greatly reduced in Group 2 and Group 4, and the water quality factors were stable during the
experiment period. The average phytoplankton density, number of species and diversity index in experimental groups grew
more rapidly and varied in less narrow range than those in control group, which showed as: Group 4 ＞ Group 1 ＞ Group 3
＞ Group 2,Group 2 ＞ Group 4 ＞ Group 1 ＞ Group 3 and Group 4 ＞ Group 2 ＞ Group 1 ＞ Group 3 on D90 respectively.
The main species of phytoplankton could be maintained as chlorophyta and diophyta species, and the proportion of single
dominant species was reduced. The species richness of protozoa increased obviously, and the average density, number of species
and diversity index of all groups showed as: Group 1 ＞ Group 3 ＞ Group 2 ＞ Group 4 on D60. The survival rate of fish was
significantly increased, which showed as: Group 1 (85.7%) ＞ Group 2 (57.1%) ＞ average (50.0%) ＞ Group 4 = Group 3
(28.6%), and A. nobilis, which needs to live in good water condition,was alive in Group 1 and Group 2.【Conclusion】Both
the local microorganism in conserving stuff and the adjustable C/N ratio of conserving stuff played active roles in improving the
aquaculture ecosystem and the stability of pond culture system could be maintained in a dynamic balance. |
