Abstract
Whether through direct supplementation of bacteria or by prebiotic supplementation thought to favour subsets of bacteria, modulation of gut microbiota constitutes an important and promising alternative to the use of prophylactic and growth promoting antibiotics in worldwide aquaculture. We fed a commercial base feed, alone or supplemented with either proprietary β-glucan, β-glucan and organic acids, citrus flavonoid or yeast cell wall supplements, to rainbow trout over a period of four weeks. Fish from each feed group were then subjected to experimental, waterborne infection with Yersinia ruckeri O1 biotype 2. Following experimental feeding, the β-glucan and organic acids supplemented group showed significantly improved feed conversion and lipid efficiency ratios. Furthermore, the β-glucan, β-glucan and organic acids and citrus flavonoid supplements proved to significantly reduce the risk of mortality in rainbow trout during experimental infection as shown by hazard ratio analysis. Resulting in 33.2%, 30.6% and 30.5% reduction in risk relative to the non-supplemented base feed, respectively, these three supplements show a promising potential either as stand-alone feed supplements, or as components in complex feed formulations.
Highlights
Intensive rearing practices and continual growth in modern aquaculture places increasing demands on fish feed sourcing, management practices and disease prevention
Given the importance of the gut homeostasis during bacterial infection (Khimmakthong et al, 2013; Ohtani et al, 2014; Tobback et al, 2010), as well as the hypothesised effects of a modulated gut microbiota, the aim of the present study was to identify prebiotic supplements that will function as stand-alone supplements and/or form the basis of synbiotic feed supplements guided by two focal points: feed performance and resistance towards experimental bacterial infection
Following the experimental feeding period, the β-glucan + OA supplemented feed group showed signs of improved feed utilization when compared to the control feed group, as well as the β-glucan supplemented feed group
Summary
Intensive rearing practices and continual growth in modern aquaculture places increasing demands on fish feed sourcing, management practices and disease prevention. Often oligosaccharides, that are administered in order to promote a beneficial microbial composition (Gibson et al, 2017; Lauzon et al, 2014), probiotics are beneficial bacteria that are directly administered (FAO & WHO, 2001; Hill et al, 2014). Synbiotic feed supplements incorporate both pre- and probiotics (Gibson & Roberfroid, 1995). By modulating the composition of the gut microbiota, the aims are to improve feed performance and feed component utilization, and to improve disease resistance, whether through direct antagonism (Wanka et al, 2018) or competition (Balcázar et al, 2008)
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
