Water quality, microbial community and shrimp growth performance of Litopenaeus vannamei culture systems based on biofloc or biofilters

Abstract

This study aimed to evaluate three different strategies for rearing Litopenaeus vannamei in systems using biofloc or biofilters, such as heterotrophic biofloc, mixotrophic biofloc and autotrophic biofilter systems. For heterotrophic treatment, sucrose was added daily with a content of 100% feed. For mixotrophic treatment, sucrose was added daily with a content of 100% feed in the first 30 days; subsequently, the sucrose addition was reduced and stopped completely. For autotrophic treatment, a biofilter was introduced without any carbon-source addition. Biofloc could remove ammonia efficiently, but the establishment of the nitrification process was slow, resulting in nitrite accumulation. The autotrophic system exhibited an accumulation of ammonia and nitrite in the early stages; however, it had the best water quality in the late phases. Nitrogen budget analysis showed that the proportion of nitrogen in the water of the autotrophic system was 42.51%, while in heterotrophic systems, most of the nitrogen in the aquaculture water was transferred to the biofloc (40.25%). Several differences were observed among bacterial communities when using different treatments. Bacterial community analysis indicated that the abundance of probiotics in autotrophic systems was higher, which is suitable for shrimp culture. Overall, the autotrophic system and mixotrophic system exhibited better shrimp growth performance.