Sodium salt medium-chain fatty acids andBacillus-based probiotic strategies to improve growth and intestinal health of gilthead sea bream (Sparus aurata)

Abstract

BackgroundThe increased demand for fish protein has led to the intensification of aquaculture practices which are hampered by nutritional and health factors affecting growth performance. To solve these problems, antibiotics have been used for many years in the prevention, control and treatment against disease as well as growth promoters to improve animal performance. Nowadays, the use of antibiotics in the European Union and other countries has been completely or partially banned as a result of the existence of antibiotic cross-resistance. Therefore, a number of alternatives, including enzymes, prebiotics, probiotics, phytonutrients and organic acids used alone or in combination have been proposed for the improvement of immunological state, growth performance and production in livestock animals. The aim of the present study was to evaluate two commercially available feed additives, one based on medium-chain fatty acids (MCFAs) from coconut oil and another with a Bacillus-based probiotic, in gilthead sea bream (GSB, Sparus aurata), a marine farmed fish of high value in the Mediterranean aquaculture.MethodsThe potential benefits of adding two commercial feed additives on fish growth performance and intestinal health were assessed in a 100-days feeding trial. The experimental diets (D2 and D3) were prepared by supplementing a basal diet (D1) with MCFAs in the form of a sodium salt of coconut fatty acid distillate (DICOSAN®; Norel, Madrid, Spain), rich on C-12, added at 0.3% (D2) or with the probiotic Bacillus amyloliquefaciens CECT 5940, added at 0.1% (D3). The study integrated data on growth performance, blood biochemistry, histology and intestinal gene expression patterns of selected markers of intestinal function and architecture.ResultsMCFAs in the form of a coconut oil increased feed intake, growth rates and the surface of nutrient absorption, promoting the anabolic action of the somatotropic axis. The probiotic (D3) induced anti-inflammatory and anti-oxidant effects with changes in circulating cortisol, immunoglobulin M, leukocyte respiratory burst, and mucosal expression levels of cytokines, lymphocyte markers and immunoglobulin T.DiscussionMCFA supplementation showed positive effects on GSB growth and intestinal architecture acting mainly in the anterior intestine, where absorption takes place. The probiotic B. amyloliquefaciens CECT 5940 exhibited key effects in the regulation of the immune status inducing anti-inflammatory and anti-oxidant effects which can be potentially advantageous upon infection or exposure to other stressors. The potential effects of these feed additives in GSB are very promising to improve health and disease resistance in aquaculture.

Co-expression Analysis of Sirtuins and Related Metabolic Biomarkers in Juveniles of Gilthead Sea Bream (Sparus aurata) With Differences in Growth Performance

“…This diversity is now starting to be elucidated, and microarray gene expression profiling of European sea bass intestine revealed pronounced spatial transcriptional changes with an over-representation of nutrient transporters and mucosal chemosensors of intestinal motility and secretion in anterior-medium intestine segments, whereas immunity markers are highly over-expressed in the posterior intestine segment (Calduch-Giner et al, 2016 ). This expression pattern has also been inferred for gilthead sea bream in both this and previous studies (Pérez-Sánchez et al, 2015 ; Estensoro et al, 2016 ; Simó-Mirabet et al, 2017b ) using intestinal PCR-arrays of selected markers of intestinal architecture and function. Moreover, the expression pattern of the fast-growing strain appears to be better suited to cope with enhanced feed intake and growth rates, as inferred by the up-regulated expression in the anterior intestine segment of genes involved in cell adhesion and epithelial integrity ( cdh1 and cdh17 ), mucus production ( muc2 ), Goblet cell differentiation ( hes1-b ) and FA transport ( fabp2 ).…”

“…The same relationship held true for markers of the GH/IGF axis, and we found that plasma level of IGF-I closely reflected differences in growth potentiality between fish strains, as previously observed when comparing the growth performance of gilthead sea bream with that of the stress sensitive common dentex (Bermejo-Nogales et al, 2007 ). Experimental evidence regarding the gilthead sea bream also indicates that IGF-I is highly responsive to changes in growth performance due to biotic and abiotic factors, including season and developmental stage (Mingarro et al, 2002 ; Saera-Vila et al, 2007 ), ration size (Pérez-Sánchez et al, 1995 ), crowding and handling stress (Rotllant et al, 2001 ), physical activity (Vélez et al, 2016 ), hypoxia (Martos-Sitcha et al, 2017 ) and dietary protein and lipid source (Gómez-Requeni et al, 2004 ; Benedito-Palos et al, 2007 ; Ballester-Lozano et al, 2015 ; Simó-Mirabet et al, 2017b ). Most of these changes in circulating levels of IGF-I are inversely correlated with plasma levels of GH due to the IGF-I feedback inhibition of pituitary GH synthesis and secretion (Pérez-Sánchez, 2000 ).…”

Insect-based diets high in lauric acid reduce liver lipids in freshwater Atlantic salmon

“…A decreased feed intake has been observed in some fish feeding trials with diets containing MCFA (Nordrum, Olli, Rosjo, Holm, & Krogdahl, ; Williams et al, ), but not in others (Figueiredo‐Silva et al, ; Hamre et al, ; Simó‐Mirabet et al, ). An increase in dietary MCT (as 8:0 and 10:0 (50:50) up to 46% of total fat) decreased the feed intake with up to 40% in Atlantic salmon, also severely affecting growth performance (Nordrum et al, ).…”

Dietary sodium heptanoate helps to improve feed efficiency, growth hormone status and swimming performance in gilthead sea bream (Sparus aurata)

“…piscicida or the intestinal parasite Enteromyxum leei (Piazzon et al., ). Experimental evidence also indicates that diets enriched in dietary sodium dodecanoic acid salt enhance feed intake and growth rates in gilthead sea bream juveniles (Simó‐Mirabet et al., ), but to our knowledge, there is no information about the potential benefits of synthetic C7‐carboxylic acid salts in fish and gilthead sea bream in particular. Taking into consideration the putative impact of SCFA and MCFA supplementation reported on fish and other animal production systems, the aim of this study is to explore the potential benefits of a commercial preparation of sodium heptanoate salt in a factorial design (2 × 2) with standard or low inclusion levels of fish meal (FM) as dietary protein source.…”