Microbial Community Structure and Its Driving Environmental Factors in Black Carp (Mylopharyngodon piceus) Aquaculture Pond

Xuemei Li,Xingbing Wu,Deguo Yang,Yongjiu Zhu,Tingbing Zhu,Lu Liu

doi:10.3390/w13213089

Abstract

This study focused on monitoring the dynamics of bacterial communities and assessment of the influences of physicochemical parameters during a culture cycle in black carp polyculture ponds. Our results showed high variation in microbial diversity and microbial composition in the water column during the culture period. Proteobacteria, Actinobacteria, and Bacteroidetes were the most abundant phyla, while the abundances of the phyla Cyanobacteria, Firmicutes, and Bacteroidetes changed in different months. Moreover, 13 abundant genera with significant difference were found between different months. Thus, samples in different months were divided into three groups according to principal coordinate analysis (PCoA) and unweighted pair-group method (UPGMA) clustering results. RDA showed that total nitrogen (TN), total phosphorus (TP), phosphate (PO43−-P), nitrate (NO3−-N), temperature (T), dissolved oxygen (DO), and pH significantly shaped the microbial community composition in different months. While Pearson correlation coefficient showed that T, SD, and pH were strongly correlated to the dominant genera. Considering some genera are potential pathogenic bacteria, we could manage the black carp pond by quickly monitoring the water temperature and SD in the future.

Highlights

IntroductionIt has been reported that Asia accounts for approximately 89% of the world’s aquaculture production, with China being the main fish producer and the largest exporter of fish and fish products [1,2,3] As the major aquaculture method in China, pond culture accounted for 74.0% of the total freshwater aquaculture production of 30,137,441 tonnes in 2019 according to MAFBC (2020) [4]
In the studied black carp polyculture ponds, the Shannon and Simpson diversity indices for aquatic bacteria increased during the mid-culture period (June, July, and August) in BP (p < 0.05), indicating that the bacterial diversity was in a dynamic succession process; the diversity decreased during the late culture period
From Redundancy analysis (RDA) analyses based on prevalent microbial taxa in this study, we found that nutrients such as total phosphorus (TP), total nitrogen (TN), PO4 3− -P, and NO3 − -N were significantly influence the microbial community in the water column, regardless of the size of the ponds

Summary

Introduction

It has been reported that Asia accounts for approximately 89% of the world’s aquaculture production, with China being the main fish producer and the largest exporter of fish and fish products [1,2,3] As the major aquaculture method in China, pond culture accounted for 74.0% of the total freshwater aquaculture production of 30,137,441 tonnes in 2019 according to MAFBC (2020) [4]. With the rapid growth of pond culture, various aquatic environmental problems such as water pollution and disease outbreaks have occurred [5]. Fish feed may be the main reason for pond water pollution. In order to meet the needs of fish growth, the protein requirement in fish feed is reported to be approximately two to three times higher than that of mammals [6]

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Conclusion