Effects of diet supplementation of soya-saponins, isoflavones and phytosterols on Atlantic salmon (Salmo salar, L) fry fed from start-feeding

Abstract

A 14-week trial was conducted to investigate the effects of antinutritional factors (ANFs) commonly present in soybean ingredients, singly and in combination, on Atlantic salmon (Salmo salar L.) fed from start-feeding. The experimental diets consisted of a negative control fish meal diet (FM), and a positive control diet with 167 g kg À1 soybean meal inclusion (SBM) and four diets based on the FM diet supplemented with 2 g kg À1 soya-saponins (SAP), 1.5 g kg À1 isoflavones (IFL), 0.3 g kg À1 phytosterols (PHS) or a mixture of these (MIX). Fish fed the SAP diet showed significantly higher growth performance than those fed FM, while the IFL treatment significantly decreased growth performance of salmon fry. Fish fed the IFL diet had significantly lower maltase activity and higher trypsin activity in proximal intestine than fish fed the FM diet. Histological differences were observed in the liver of fish fed the IFL diet, characterized by reduced size of the hepatocytes. Fish fed the PHS and IFL diets showed the highest frequencies of skeletal deformities among the six treatments. In conclusion, the results indicate that purified isoflavones may negatively affect growth performance, intestinal function, liver metabolism and bone formation of salmon fry.

Effects of dietary soy isoflavones on estrogenic activity, cortisol level, health and growth in rainbow trout, Oncorhynchus mykiss

“…However, the degree of hepatocyte vacuolization was lower than in fish fed diets without isoflavones. Also, isoflavone-supplemented diets induced alterations of digestive enzymes necessary for carbohydrate digestion as confirmed by decreased growth of treated fish (Gu et al, 2014). Our histopathological analysis of rainbow trout fed different level of isoflavones showed normal morphology of intestine and liver, confirming adequate welfare of the fish as in the previous study (Gu et al, 2014), but no effect on their growth.…”

“…Also, isoflavone‐supplemented diets induced alterations of digestive enzymes necessary for carbohydrate digestion as confirmed by decreased growth of treated fish (Gu et al., ). Our histopathological analysis of rainbow trout fed different level of isoflavones showed normal morphology of intestine and liver, confirming adequate welfare of the fish as in the previous study (Gu et al., ), but no effect on their growth. The slight degree of liver steatosis was probably not caused by isoflavones but by the basal diet used in this trial.…”

Impact of Down-Stream Processing on Functional Properties of Yeasts in Diets of Atlantic Salmon (Salmo Salar): Implications for Gut Health

“…In the current freshwater experiment, the histological ndings were in accordance with previous studies performed in juveniles 16,34,35 , with only mild SBMIE symptoms detected. It has been suggested that the immaturity of intestinal functions may be responsible for the mild in ammatory changes observed in juveniles, compared to post-smolt salmons 34,35 . Despite mild symptoms, our results show that both AWA and ICU were e cient in alleviating SBMIE, as demonstrated by changes associated with widening of lamina propria, similar to those fed the FM control diet.…”

“…Although dietary exposure to SBM is known to induce SBMIE in the seawater phase of the Atlantic salmon 4,9,15 , the effects are less severe during the freshwater phase 16,34,35 . In the current freshwater experiment, the histological ndings were in accordance with previous studies performed in juveniles 16,34,35 , with only mild SBMIE symptoms detected. It has been suggested that the immaturity of intestinal functions may be responsible for the mild in ammatory changes observed in juveniles, compared to post-smolt salmons 34,35 .…”

Dietary Supplementation of a Mixture of Saponin-Rich Plants to Reduce Ammonia-Nitrogen Excretion in Juvenile Nile Tilapia (<i>Oreochromis</i> <i>niloticus</i>)

“…Moreover, similar results have also been reported in other fish species. Gu et al [12] thus reported a beneficial role of soybean-saponins in Atlantic salmon (Salmo salar) fry resulting in increased growth, associated with an increased liver function. However, they did not improve juveniles seabream (Sparus aurata [13], [14]), European seabass (Dicentrarchus labrax [15]), juvenile turbot (Scophthalmus maximus [16]) or juvenile Japanese flounder (Paralichthys olivaceus [17]) growth performances.…”