Effects of the algicidal bacterium CZBC1 on microalgal and bacterial communities in shrimp culture

• Main Authors: Hu, X, Wen, G, Xu, W, Xu, Y, Su, H, Yang, K, Li, Z, Cao, Y
• Format: Article
• Language: English
• Published: Inter-Research 2019-06-01
• Series: Aquaculture Environment Interactions
• Online Access: https://www.int-res.com/abstracts/aei/v11/p279-290/

Algicidal bacteria may play a role in controlling algal blooms. Previously, a Bacillus cereus strain (CZBC1) was shown to have specificity against harmful Cyanophyta. To elucidate the characteristics of microalgal and bacterial communities in shrimp culture associated with the algicidal bacterium CZBC1 and its combined use with the addition of organic carbon, we established a shrimp culture system in which the dominant macroalgal species were Oscillatoria chlorina (Cyanophyta) and Chlorella pyrenoidosa (Chlorophyta). We studied water-column microalgal and bacterial communities in control (GC), bacteria (GB), and bacteria-carbon (GBC) treatment groups at the mid-point (Day 28) and end (Day 56) of the experiment. The algicidal bacterium CZBC1 was able to regulate abundance of Cyanophyta on Days 28 and 56 in GB and GBC. Abundances of Cyanophyta on Days 28 and 56 ) in GB (<0.44%) and GBC (<0.37%) were significantly lower than that in GC (25.58 to 40.87%), and those of Chlorophyta in GB (86.83 to 92.85%) and GBC (99.63 to 99.94%) were significantly higher than those in GC (52.52 to 67.35%). Multiple linear stepwise regression analysis showed that the amount of applied algicidal bacterium CZBC1 had the most significant negative correlation with the abundance of Cyanophyta (R = 0.973, p < 0.01). On Days 28 and 56, the average well color development value (Biolog), bacterial count, and bacterial community structure were relatively stable in GB, while the addition of a carbon source increased the amount of bacteria and affected the composition of the bacterial community in GBC. Our findings suggest that algicidal bacteria can be used to regulate microalgal communities and stabilize the metabolic potential of bacterial communities in aquaculture.