Aquaculture 2025

March 6 - 10, 2025

New Orleans, Louisiana USA

Add To Calendar 07/03/2025 11:45:0007/03/2025 12:05:00America/ChicagoAquaculture 2025THE SUPPLEMENTATION OF AUTOCHTHONOUS PROBIOTIC, Lactococcus lactis MA5, IMPROVES ACUTE HYPOXIA STRESS RESISTANCE FOR HYBRID CATFISH (Ictalurus punctatus × I. furcatus)Salon DThe World Aquaculture Societyjohnc@was.orgfalseDD/MM/YYYYanrl65yqlzh3g1q0dme13067

THE SUPPLEMENTATION OF AUTOCHTHONOUS PROBIOTIC, Lactococcus lactis MA5, IMPROVES ACUTE HYPOXIA STRESS RESISTANCE FOR HYBRID CATFISH (Ictalurus punctatus × I. furcatus)

Jing Huang*, Heather R. Jordan, Caitlin E. Older, Matt J. Griffin, Peter J. Allen, David J. Wise, Ana Beatriz S. Farias, Penelope M. Goodman, J. Grant Reifers, and Fernando Y. Yamamoto

 

Thad Cochran National Warmwater Aquaculture Center

Mississippi State University

Stoneville, MS, 38776

jh4728@msstate.edu

 



Hypoxia is an ongoing challenge during aquaculture production. With the recent intensification of catfish production systems to reduce production cost, hypoxia has become a greater challenge, affecting growth performance and disease resistance. Feed supplemented with probiotics have shown stress regulating responses, growth promotion, and immune modulation in animals. In our previous study, an autochthonous lactic acid producing probiotic, Lactococcus lactis MA5, demonstrated beneficial effects as a dietary supplement for hybrid catfish, increasing survival after Aeromonas hydrophila infection. In this study, lyophilized MA5 was evaluated as a dietary supplement to ameliorate hypoxia stress in a 56-day feeding trial. In total, 450 hybrid catfish juveniles (initial weight 16.4 ± 1.6 g) were equally distributed into 18 tanks as a completely randomized design with three experimental groups (Control, 104 and 106 CFU/g of MA5, N=6) in a flow-through system. The lyophilized probiotic was top coated with 1% saturated oil on a commercial feed. After the feeding trial, a significant increase in body weight was observed for fish fed 106 CFU/g compared to the control group. Upregulation of the GPx1, iNOS, and downregulation of hsp70 mRNA expression in the intestine was observed for fish fed MA5-containing diets. Digesta samples were collected from the posterior intestine for microbiota analyses after the feeding trial, and a high relative abundance of Lactococcus spp., Cetobacterium spp., and Plesiomonas spp. were found in all the treatment groups. Ten remaining fish per tank were subjected to an acute hypoxia challenge, to investigate the potential stress regulation of MA5. Under acute hypoxia stress, fish fed with probiotics diets displayed an increase in serum glucose and cortisol levels with higher levels of hemoglobin, total protein, and red blood cells when compared to the fish fed the control diet. In addition, the remaining fish were subjected to a bacterial challenge via exposure to Edwardsiella ictaluri S97-773. Significantly higher survival was observed after being fed 106 CFU/g of probiotics diet (106 CFU/g: 84%, Control: 66%) for 56 days. In conclusion, MA5 dietary supplementation can regulate the stress response when fish are exposed to an acute hypoxia stressor, with possibly benefits observed as a result of oxidation regulation. Additionally, MA5 supplementation may confer higher survival upon E. ictaluri challenge.