|
|
|
| Changes in Shape and Nutrients in Decomposition of Tilapia Feces |
| CHEN Jiajie,TAN Hongxin,YU Zhongli,LUO Guozhi,GAO Jinfang,XU Yaqian |
|
|
|
|
Abstract The bioflocculation process in a reactor was observed under a microscope and scanning electronic microscope and crude protein ,amino acids and extracellular polymeric substances were determined in feces of NEW GIFT Oreochromis niloticus collected in a recirculating aquaculture system .It was found that the feces became loosely ,feces developed into bioflocs framed with filamentous fungi with reaction of the bioflocs .With the decomposition of feces ,there was slow increase in level of the ammonium ,with the peak value of 7 .46 mg/L in the reactor on the 7th day ,and the nitrite was shown to be increased to 7 .81 mg/L , with the rapidly accumulative nitrate of 21 .6 mg/L .On the 9th day ,the crude protein had the peak content of 26 .37% ,and then decreased to 25 .45% ,and the total amino acids was found to be the peak value of 20 .44% on the 7th day ,and then decreased to 18 .11% .There were lower level of essential amino acids in bioflocs than in the feed (13 .03% ) , even though higher than in the feces (9 .36% ) . The polysaccharides were primariy substance in the loosely bound extracellular polymeric substances(LB‐EPS) in the bioflocs ,while protein was the main component in the tightly bound EPS(TB‐EPS)in the bioflocs .
|
|
Received: 25 October 2015
|
|
|
|
|
|
|
