Lipoxygenase Enzymes, Oligosaccharides (Raffinose and Stachyose) and 11sA4 and A5 Globulins of Glycinin Present in Soybean Meal Are Not Drivers of Enteritis in Juvenile Atlantic Salmon (Salmo salar)

Artur N Rombenso,Andrew T James,David Blyth,Cedric J Simon,Teisha Nikolaou

doi:10.3390/app11199327

Abstract

Soybean meal has been largely investigated and commercially used in fish nutrition. However, its inclusion levels have been carefully considered due to the presence of antinutritional factors, which depending on a series of factors might induce gut inflammation damaging the mucosal integrity and causing enteritis. Several strategies including genetic engineering have been applied attempting to reduce or eliminate some of the antinutritional factors. Accordingly, we assessed the intestinal health of juvenile Atlantic salmon fed high levels of speciality soybean genotypes with reduced-to-no content amounts of lipoxygenases, altered glycinin profile and reduced levels of oligosaccharides. No major signs of enteritis, only indication of enteritis progression, was noticed in the soybean meal-based diets illustrated by mild changes in distal intestine morphology. Whereas fish, fed fishmeal control feeds, displayed normal distal intestine integrity. Speciality soybean types did not improve intestinal health of juvenile Atlantic salmon suggesting these antinutrients are not drivers of the intestinal inflammatory process in this species. No additional benefits in terms of production performance or blood biochemistry were noticed in the speciality soybean types compared to the traditional soybean.

Highlights

Soybean meal (SBM) has been largely investigated and commercially used in fish nutrition
There were no major signs of enteritis, only an indication of enteritis progression was noticed in the SBM-based diets illustrated by mild changes in distal intestine morphology, including reduced number and length of mucosal folds, enlargement of the apical zone of mucosal folds, thickening of lamina propria, and changes in abundance of goblet cells (Figure 1B–D)
Soybean meal-induced enteritis was not observed in juvenile Atlantic salmon, despite the high dietary SBM inclusion level of 30%

Summary

Introduction

Soybean meal (SBM) has been largely investigated and commercially used in fish nutrition. SBM offers several advantages to the aquafeed industry including worldwide availability, competitive pricing, consistent nutritional quality, and an acceptable amino acid profile it displays some constraints, mainly associated with antinutritional factors [1,2]. There is a long list of antinutritional factors including saponins, lectins, phytic acid, oligosaccharides, isoflavones, and allergens, among others [1]. These antinutrients are known to impair feed intake, palatability, growth performance, digestive enzymes and in some instances induce gut inflammation damaging the mucosal integrity and causing enteritis [1,3,4,5,6,7,8]. The degree of physiological impairments induced by dietary SBM is linked to the SBM inclusion level, blends of raw materials, duration of feeding SBM-based feeds, and the species sensitivity to antinutritional factors [3,4,5,6,9,10].

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Results

Conclusion