Impact of probiotics on growth performance and shrimp survival: A meta-analysis

Probiotics have emerged as promising alternatives for improving resistance to diseases and stimulating growth of farmed shrimp. The aim of the present work was to assess the effect of probiotic addition on shrimp survival and growth performance through meta-analysis. PubMed, SciELO and Google Scholar search engines were searched for relevant studies published from 1980 to 2017 without language exclusion. We only selected the experiments from articles using penaeid shrimps without apparent disease, with the results published in peer-reviewed journals with any dispersion measure. Survival, specific growth rate (SGR) and feed conversion ratio (FCR) were selected as outcomes. We evaluated experimental design, penaeid shrimp species, larval or postlarval stage, probiotic strain, modes of administration among others. A total of 100, 60 and 49 experiments were included to assess probiotic effects on survival, SGR and FCR, respectively. Probiotics increased survival compared to controls (SMD=3.068, 95% CI 2.594 to 3.543) and improved SGR (SMD = -3.811, 95% CI 3.269 to 4.354) and FCR (SMD = -3.194, 95% CI-3.469 to -2.920) in the pooled standardized mean difference random effect model, considering the source of heterogeneity and publication biases (i.e. where the decision to publish or not depends on the outcome of the experiment, e.g. withhold negative outcomes). Survival, SGR and FCR were improved in shrimps treated with probiotic. To our knowledge, this is the first report of a meta-analysis designed to investigate the effects of probiotics on shrimp survival and growth performance.