The supplementation of a commercial prebiotic, probiotic or their combination affected the production performance and intestinal microbiota of red drum Sciaenops ocellatus L. but did not modulate plasma innate immune response

Authors: YAMAMOTO, FERNANDO - Mississippi State University; ELLIS, MATTHEW - Texas A&M University; BOWLES, PAUL - Texas A&M University; SUEHS, BLAINE - Texas A&M University; CARVALHO, PEDRO - Texas A&M University; Older, Caitlin; Hume, Michael; GATLIN III, DELBERT - Texas A&M University

Submitted to: Aquaculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/26/2022
Publication Date: 9/30/2022
Citation: Yamamoto, F.Y., Ellis, M., Bowles, P.R., Suehs, B.A., Carvalho, P.L., Older, C.E., Hume, M.E., Gatlin Iii, D.M. 2022. The supplementation of a commercial prebiotic, probiotic or their combination affected the production performance and intestinal microbiota of red drum Sciaenops ocellatus L. but did not modulate plasma innate immune response. Aquaculture. https://doi.org/10.3390/ani12192629.
DOI: https://doi.org/10.3390/ani12192629

Interpretive Summary: Farmed fish can be particularly susceptible to disease outbreaks due to stress associated with farming conditions, such as high stocking density. Modulating the gut microbiota is one method to improve resistance to disease and can be achieved with the use of prebiotics or probiotics. ARS scientists in collaboration with scientists at Texas A&M University evaluated if inclusion of prebiotics and probiotics in diets had any influence on the gut microbiota and immune system of red drum. Fish fed diets supplemented with probiotics had better growth performance than the fish fed the non-supplemented diets and higher whole-body protein composition. Both prebiotics and probiotics resulted in effects on the gut microbiota, including higher relative abundances of Pediococcus, a bacterial genus associated with host benefits. These results suggest inclusion of prebiotics and/or probiotics in diets may be useful for red drum farming. Further research would be needed to confirm these results and determine if these feed additives can impart protective effects, particularly in the context of stressful conditions or disease outbreaks.

Technical Abstract: In the present study, the potential synergism between the beneficial bacteria contained in probiotics with the fermentable complex carbohydrates (or prebiotics) were explored for red drum using the commercial products BactocellTM and Grobiotic-A. Four experimental diets were formulated and supplemented with either 1 g kg-1 of Bactocell, 20 g kg-1 of Grobiotic-A, or their combination. A non-supplemented diet served as a control. Groups of twelve juvenile red drum with an average weight of ~5.5 g were distributed in 38-L aquaria (n=4) and offered the four experimental diets for 56 days with rations that were weekly adjusted according to the fish body weight. At the end of the feeding trial, production performance, whole-body proximate composition, plasma immunological responses, and the intestinal microbial community were evaluated. Data were analyzed as a mixed model, having a 2 × 2 factorial design and the variance caused by the disposition of the aquaria was statistically blocked. Fish fed diets supplemented with probiotics had a better growth performance than the fish fed the non-supplemented diets and a higher protein content in their whole-body composition. Fish treated with diets supplemented with the prebiotics presented a lower concentration of circulating protein in the plasma. No differences were observed in feed efficiency, survival, plasma total immunoglobulins, whole-body lipid and ash, and protein conversion efficiency. Fish intestinal microbiome presented an alpha and beta diversity significantly affected by the dietary treatments. Interestingly, a higher relative abundance of the lactic acid genus Pediococcus sp. was observed for fish fed diets supplemented with prebiotics. A higher relative abundance was also observed for the predicted functions of the microbial metagenome, where 84 pathways were significantly affected for fish treated with prebiotics and 18 pathways for the fish fed probiotics. Many of these pathways involved the biosynthesis of essential amino acids and nucleotides. Even though no potential synergistic effect was observed for the supplementation of both commercial products, the individual inclusion of prebiotics and probiotics positively affected the growth performance and intestinal health of red drum.