Use of Probiotic Bacteria and Bacteriocins as an Alternative to Antibiotics in Aquaculture

Abstract

In addition to their use in human medicine, antimicrobials are also used in food animals and aquaculture, and their use can be categorized as therapeutic against bacterial infections. The use of antimicrobials in aquaculture may involve a broad environmental application that affects a wide variety of bacteria, promoting the spread of bacterial resistance genes. Probiotics and bacteriocins, antimicrobial peptides produced by some types of lactic acid bacteria (LAB), have been successfully tested in aquatic animals as alternatives to control bacterial infections. Supplementation might have beneficial impacts on the intestinal microbiota, immune response, development, and/or weight gain, without the issues associated with antibiotic use. Thus, probiotics and bacteriocins represent feasible alternatives to antibiotics. Here, we provide an update with respect to the relevance of aquaculture in the animal protein production sector, as well as the present and future challenges generated by outbreaks and antimicrobial resistance, while highlighting the potential role of probiotics and bacteriocins to address these challenges. In addition, we conducted data analysis using a simple linear regression model to determine whether a linear relationship exists between probiotic dose added to feed and three variables of interest selected, including specific growth rate, feed conversion ratio, and lysozyme activity.

Keywords: antibiotic; aquaculture; bacteriocin; biotechnology; probiotic.

Figure 1

Probiotics development processes for feed and techniques to improve probiotic supplementation effects. (A) The different stages before probiotic bacteria use in aquaculture. From a sample, tests to identify genus and species are performed. Then, tests with and without the use of living organisms evaluate its properties and use as a food additive in animal feed. (B) In order to optimize aquaculture production processes, different techniques have been used. Probiotic microorganisms are those that confer benefits to the host; prebiotics are nondigestible food components that benefit the colonization of certain bacteria, such as probiotics; synbiotics are the combination of probiotics and prebiotics in the same product; mixtures of probiotics are prepared from the combination of more than one probiotic microorganism to potentiate their action; and postbiotics, dead probiotics or byproducts, are commonly associated with safety [38,39,40,42].

Figure 2

Probiotics and bacteriocins mode of action. Probiotics beneficial effects come from several mechanisms. They secrete digestive enzymes that contribute to macronutrients breakdown, increasing absorption by the host. They can act by blocking pathogens due to competition for space and nutrients, by stimulating the immune system (without the presence of disease) and via the production of antimicrobial substances (such as lactic acid and bacteriocins). Bacteriocins mode of action may vary according to their characteristics. They can lead to death via pore formation, preventing the action of peptidoglycan transporters and, consequently, cell wall synthesis, and via damage to genetic material and protein synthesis. Probiotics, bacteriocins, and the host nutritional improvement contribute to pathogens elimination and diseases control [121,122].

Figure 3

Data analysis revealed no significant correlation between probiotic dose in feed and SGR in fish. The circles represent the mean of experimental groups (n = 3; either control group or probiotics treatment group) tested in the studies considered for the regression analysis.

Figure 4

Data analysis revealed significant correlation between probiotic dose in feed and FCR. The circles represent the mean of experimental groups (n = 3; either control group or probiotics treatment group) tested in the studies considered for the regression analysis.

Figure 5

Data analysis revealed significant correlation between probiotic dose in feed and Lysozyme activity. The circles represent the mean of experimental groups (n = 3; either control group or probiotics treatment group) tested in the studies considered for the regression analysis.