Soybean meal induces enteritis in turbot Scophthalmus maximus at high supplementation levels

Abstract

The goal of the present study was to find whether higher soybean meal (SBM) levels might trigger soybean meal-induced enteritis (SBMIE) in turbot. If so, caution must be taken when mixing ingredients containing saponins and other antinutrients to avoid SBMIE like symptoms. In a 8 week feeding trial conduced on turbot, three isonitrogenous and isolipidic diets were formulated to include 26%, 40% and 54% SBM to progressively replace 30%, 45% and 60% fish meal (FM) in a FM based diet, respectively. The results showed that SBM caused dose-dependent decreases in growth performance and nutrient utilization. Enteritis developed in the distal intestine in the inclusion range of 26-54%. Dose-dependent increases in severity of the inflammation, with concomitant alterations in brush border membrane enzymes and inflammatory marker genes expression were seen. Our results confirm the hypothesis that high inclusion level of SBM may cause similar inflammatory changes as observed in several other fish species. Thus, caution must be taken when formulating turbot diets based on ingredients that may contain saponins and other antinutrients. Moreover, turbot is also a candidate species for the study of causes and mechanism of diet induced inflammation in the intestine of fish.

Administration of host‐derived probiotics does not affect utilization of soybean meal enriched diets in juvenile turbot (Scophthalmus maximus)

“…Surprisingly, the DFI remained at a similar level in both the FM ctrl and the SBM supplemented treatments. This is in contrast to previous studies which reported a DFI decrease when plant feedstuff was used at comparable substitution levels (Bai et al, ; Bonaldo et al, ; Fuchs et al, ; Gu et al, ). However, there are also investigations that detected no significant decrease in DFI (Sevgili et al, ; Yun et al, ).…”

“…Solely in the SBM + degrad treatment a significant CF increase in comparison to the FM diet was detected. Conversely, Bonaldo et al () and Gu et al () found a significant decrease of the CF with increasing SBM inclusion. Here, Bonaldo et al () assumed that the lower CF was a consequence of a reduced muscle development, resulting in a lower thickness of turbot filets.…”

“…In 2016, Gu and coworkers were able to cause a dose‐dependent decrease of growth performance in juvenile turbot fed level of 26%, 40% and 54% SBM in DM. Here, they triggered SBM induced enteritis in the distal intestine with an increasing severity in correlation to the ascending SBM doses (Gu et al, ). Unfortunately, Gu et al did not indicate the exact concentrations of total saponin.…”

“…This is in line with the findings of several other studies on turbot. Here, growth performance and feed conversion were negatively affected by the administration of various plant proteins in general (Fournier, Huelvan, & Desbruyeres, ; Nagel et al, ) or SBM and mixtures of both in particular (Bai et al, ; Bonaldo et al, , ; Gu et al, ; Sevgili et al, ; Yun, Mai, Zhang, & Xu, ).…”

“…Soybeans contain triterpenoid saponins and the aglycones are divided into soyasapogenols A, B, C, D and E. Correspondingly, their glycosides are named group A saponins, group B saponins et cetera (Tarade, Singhal, Jayram, & Pandit, ). It was pointed out that saponins play a crucial role in the onset of intestinal diseases like enteritis (Gu et al, ; Knudsen et al, ; Krogdahl et al, ). However, the mechanisms behind the etiology of these diseases are not yet fully understood and it remains challenging to trace the components of soy products that are actually involved.…”