Utilisation of Humic Substances as a Feed Additive in Aquaculture: A Meta-Analysis

Interest has recently grown in the research of humic substances (HS) as a potential aquaculture feed additive, resulting in a growing number of publications. However, previous studies have shown varying results. Therefore, to gain a comprehensive understanding of the effects of HS, a quantitative analysis conducted through a meta-analysis is required. This study employed a meta-analysis approach to evaluate the effect of HS as a feed additive on the specific growth rate (SGR) and feed conversion ratio (FCR) of fish aquaculture. The Preferred Reporting Items for Systematic and Meta-Analysis (PRISMA) method was used to collect the data. Multiple databases were searched to identify relevant articles from scholarly journals. Ultimately, 18 publications that met the requirements were included in the analysis using OpenMEE software. The results revealed an effect size (comparing the control and the HS-supplemented groups) of 0.154 (95 % CI, P < 0.001) for SGR. Additionally, there was a notable improvement in FCR with an effect size of -0.220 (95 % CI, P < 0.001). However, it is important to note that the analysis showed high heterogenicity (I2 values of 98.87 % and 97.91 % for SGR and FCR, respectively). In conclusion, HS supplementation may significantly improve fish growth and reduce FCRs in aquaculture. This meta-analysis contributes valuable insight into the use of HS as a beneficial feed additive in aquaculture practices.