Dietary probiotic supplementation improved gut amylase to trypsin ratio in European seabass reared at different temperatures and survival after handling stress

Abstract

Event Abstract Back to Event Dietary probiotic supplementation improved gut amylase to trypsin ratio in European seabass reared at different temperatures and survival after handling stress Luís F. Pereira1, 2*, José Gonçalves2, Andreia F. Domingues1, Maria João D. Peixoto1, Sthelio F. Braga3, Kanokwan Sansuwan4, Gonçalo Santos5 and Rodrigo Ozorio1, 2* 1 CIIMAR, Portugal 2 ICBAS - Abel Salazar Biomedical Sciences Institute, University of Porto., Portugal 3 UFPB - Universidade Federal da Paraíba., Brazil 4 Department of Zoology, Faculty of Science, Kasetsart University., Thailand 5 BIOMIN Holding GmbH, Austria Antibiotics and chemical treatments are often used as disease control strategy. A prophylactic and alternative method to this chemical approach are the probiotics [1]. Probiotics are defined as "live microorganisms which when administered in adequate amounts confer a health benefit on the host" (FAO, 2001). The benefits of probiotic treatments are improvements in host nutritional retention [2], antagonistic properties to bacterial pathogen proliferation [3], modulation of immune responses [4], among others. Temperature plays a major role in dietary nutrient utilization and immune responses in fish, and have a modulatory effect on probiotic activity in intestine. The current study evaluated the use of a dietary probiotic supplementation in European seabass (Dicentrarchus labrax), one of the most important fish species in Southern Europe. Fish were fed on a multi-species probiotic (Bacillus sp., Pedicoccus sp., Enterococcus sp., Lactobacillus sp. ), reared under 3 different temperatures (17, 20 and 23 ºC) for 70 days. Fish were pair-fed, fixed to the voluntary feed intake of fish reared at 17 º C, in order to have similar probiotic intake among the temperature groups. Final body weight tripled initial weight (12.7 to 30.7g). At the end of the growth trial, all fish were subjected to a handling stress, in which stocking density increased by 6 fold (from 4 kg/m3 to 25 kg/m3), followed by a 15 min chase with a pole. Growth performance was not affected by the dietary treatment. Post-stress cumulative mortality were significantly higher in the 17ºC control group (figure 1A). Digestive enzymes activity were significantly affected by temperature and diet interaction. The activity ratio of amylase to trypsin (figure 1B) increased with temperature and dietary probiotic supplementation, an indication that probiotic treatment at 23oC have a positive influence on the metabolic flexibility of carbohydrate-protein utilization. Non-specific immune response (ACH50 activity) were temperature-sensitive, with no dietary influence. Glutathione, an important antioxidant marker, was significantly affected by temperature and diet interaction. The current study showed a protective effect of dietary probiotic supplementation in seabass, and those changes were temperature sensitive. Figure 1 Acknowledgements This research was partially supported by the European Regional Development Fund (ERDF) through the COMPETE - Operational Competitiveness Programme and national funds through FCT – Foundation for Science and Technology, under the project “PEst-C/MAR/LA0015/2013.