Effects of microbial products and extra carbon on water quality and bacterial community in a fish polyculture system

Abstract

A 55‐day mesocosm experiment was conducted to evaluate the effects of commercial microbial products (Novozymes Pond Protect and Novozymes Pond Plus) and extra carbon (glucose) on water quality and bacterial community in a fish polyculture system. A 2 × 2 layout, including four treatments (non‐supplementation of the microbial products or glucose, adding glucose, adding the microbial products and adding the microbial products and glucose in combination), was established. The microbial products and glucose were added on the 40th day, 46th day and 52th day. Ammonia, nitrite and nitrate reduced in the tanks after glucose addition, while adding the microbial products did not significantly affect ammonia, nitrite, nitrate, reactive phosphate, total nitrogen, total phosphorus, chemical oxygen demand and total organic carbon. Adding the microbial products and glucose affected relative abundance of some bacterial taxa, but did not reshape bacterial community. Non‐positive interactive effect on water quality and bacterial community was detected between the microbial products and glucose. This study reveals that supplementation of the microbial products did not benefit water quality in the fish polyculture system, and glucose addition could reduce ammonia, nitrite and nitrate.

Effects of Chitosan–Gentamicin Conjugate Supplement on Non-Specific Immunity, Aquaculture Water, Intestinal Histology and Microbiota of Pacific White Shrimp (Litopenaeus vannamei)

“…The salinity, total alkalinity, NH 3 , and NO 2 − in all the groups were increased, while the NO 3 − content in all groups was decreased. The overall change trends of NH 3 and NO 2 − were similar to those in studies by other experts [ 28 , 29 ]. It is likely that the excessive input of feeds and massive deposition of fecal matter during the feeding period—causing organic matter accumulation, decomposition, and oxygen consumption, resulting in the bottom of tank entering a hypoxic state, a large number of anaerobic bacteria multiplying, and the incomplete decomposition of organic matter—produced a large number of toxic and harmful physical–chemical factors such as ammonia nitrogen and nitrous nitrogen [ 30 ].…”

Effects of adding EM bacteria and mechanical aeration on water quality, growth and antioxidant status of Meretrix meretrix and Exopalaemon carinicauda farmed in the clam–shrimp polyculture system

“…In the present study, EM bacteria supplementation could decrease nitrite and COD Mn , while it did not result in significant reduction in ammonia, nitrate, TIN and TIP. The result indicated that adding EM bacteria could reduce the stress of water organisms on nitrite to some extent, but it had limited function in improving water quality in the polyculture system, which was similar with Zheng et al (2019) reports. Zhou et al (2017) assumed that the function of exogenous bacteria from commercial microbial products in improving water quality in a fish polyculture system might depend on whether the exogenous bacteria could successfully colonize the resident environment and dominate in the native bacterial community.…”

“…found that microbial products were beneficial for enhancing sea cucumbers' health and improving disease resistance by modulating the intestinal microflora and stimulating innate immune system. On the contrary, in other studies, adding microbial products in aquaculture systems could not significantly improve water quality and production performance (Li & Boyd, 2016;Zheng et al, 2019). In fact, the effect of exogenous bacteria on the environment depends on the survival of bacteria in the new environment and competition with native bacteria (Zhou et al, 2017).…”

“…Effective microorganism (EM) bacteria liquid, containing bacillus, photosynthetic bacteria and lactic acid bacteria, is a common microbial product, which has been widely used in aquaculture (Meng et al, 2011). Although various microbial products are emerging in aquaculture, their effectiveness remains controversial during the actual culture process (Lukwambe et al, 2015; Zheng et al, 2017, 2019). Some studies reported that supplementation of microbial products could improve water quality and enhance aquatic organisms' health (Du et al, 2013; Li, Li, et al, 2015; Meng et al, 2011; Zhang et al, 2014).…”

Effects of sucrose addition on water quality and bacterioplankton community in the Pacific White Shrimp ( Litopenaeus vannamei ) culture system

“…Previous studies have indicated that increasing the C/N ratio of input could simplify the microbial community and induce the accumulation of some specific bacterial groups (Joshua et al, 2018; Shang et al, 2018; Wei et al, 2016). In this study, the bacterioplankton communities mainly consisted of Proteobacteria, Actinobacteria and Bacteroidetes in both CK and the addition of sucrose groups, and these phyla were also reported to account for 74%–96% relative abundance of bacterial community in rearing water of shrimp (Rungrassamee et al, 2014; Zheng et al, 2019). However, the relative abundance of Proteobacteria, Actinobacteria and Bacteroidetes in CK and the addition of sucrose groups were significantly ( p < 0.05) different.…”