Periphyton use on microbial dynamics, water quality, and Nile tilapia growth in rearing tanks

Abstract: The objective of this work was to evaluate the effect of the use of an artificial substrate for periphytic biofilm growth on the microbiological composition of the biofilm, water quality, and zootechnical performance of Nile tilapia (Oreochromis niloticus) in rearing tanks. The experiment consisted of two treatments: presence and absence of artificial substrate for the growth of periphyton, with five replicates. Water quality parameters were evaluated throughout the entire experimental period. Every two weeks, samples of the periphyton were collected for the analysis of its microbiological composition and biometric measurements of the fish were performed. The number of heterotrophic bacteria in the biofilm increased during the experimental period, but that of Aeromonas decreased with the use of the artificial substrate. The total ammonia nitrogen in the tanks with periphyton reduced in 30% compared with that of the control. Tilapia reared with the biofilm showed a final weight 2.4 times greater than that of those subjected to the control, as well as an increase of 59.19% in their productivity. The use of an artificial substrate for periphytic biofilm in Nile tilapia rearing tanks favors the maintenance of the quality of the culture water, the protection of the fish against pathogens, and the improvement of the zootechnical performance of the fish.

摘要：本研究旨在评估养殖池内添加用于周丛生物膜（periphytic biofilm）生长的人工基质，对生物膜微生物组成、水体水质以及尼罗罗非鱼（Oreochromis niloticus）养殖生产性能的影响。本实验设置两组处理：添加人工基质组与未添加对照组，每组设置5个重复。整个实验周期内均监测水质参数；每两周采集一次周丛生物样本以分析其微生物组成，并开展鱼类生长性状测定。实验期间，生物膜内的异养细菌（heterotrophic bacteria）数量随实验推进逐步上升，但添加人工基质后气单胞菌（Aeromonas）的种群数量有所下降。相较于对照组，添加周丛生物膜的养殖池总氨氮（total ammonia nitrogen）含量降低了30%。采用该生物膜养殖的尼罗罗非鱼，终末体重较对照组高出2.4倍，养殖生产力提升59.19%。在尼罗罗非鱼养殖池中使用人工基质培育周丛生物膜，有助于维持养殖水体水质、保护鱼类抵御病原微生物，并改善鱼类的养殖生产性能。