Influence of certain soybean antinutritional factors supplemented to a casein-based semipurified diet on intestinal and liver morphology in fingerling rainbow troutOncorhynchus mykiss

Abstract

To investigate the cause of morphological changes occurring in the liver and intestine of rainbow trout Oncorhynchus mykiss fed defatted soybean meal (SBM)-based non-fish meal diets, morphological observations were conducted on fish fed casein-based semipurified diets supplemented with soybean antinutritional factors (soya saponin, soya isoflavone, soya lectin, oligosaccharide, Ca-phytate and their mixture). Hepatocytes and the epithelial cells in the hepatic ducts were not atrophied in any of the treatments. Lack of microvilli and pinocytotic vacuoles, and fatty degeneration of the epithelial cells were observed in the distal intestine of fish fed diets containing soya saponin. The proliferation of connective tissue in the mucosal folds and submucosa was shown in the distal intestine of fish fed the diet containing all substances including lectin. These results suggest that both saponin and lectin are the responsible factors in SBM for the occurrence of morphological changes of the distal intestine in rainbow trout fed SBM-based diets.

Preliminary Evaluation of Rainbow Trout Diets Containing PepSoyGen, a Fermented Soybean Meal Product, and Additional Amino Acids

“…This is not unexpected, as soybean meal typically does not contain enough methionine to meet the nutritional requirements of rainbow trout [1,44]. Methionine has been supplementated in other studies using soybean meal or soy protein concentrates fed to rainbow trout [5,9,45]. Incorporating other amino acids in addition to methionine did lead to an increase in the percentage of these amino acids in the diets, but appeared to provide no noticeable improvement to any of the parameters studied.…”

“…However, primarily because of the presence of numerous anti-nutritional factors [2][3][4][5] and negative effects on intestinal form and function [5][6][7][8][9][10][11][12], soybean meal inclusion in trout diets is limited.…”

Influence of soya saponin, soya lectin, and cholyltaurine supplemented to a casein-based semipurified diet on intestinal morphology and biliary bile status in fingerling rainbow trout Oncorhynchus mykiss

“…Therefore, the morphological change in the lamina propria of rainbow trout fed SBM-based diets is likely to be caused by a combination of soya lectin and other unidentified ANF(s). On the other hand, morphological changes in the liver were not observed for any of the diets supplemented with soybean ANFs in the described experiment [8]. To improve the nutritional value of soybean products, it is important to identify the soybean ANFs responsible for morphological changes in the distal intestine and liver, and to develop methods for relieving the negative effects of the ANFs.…”

“…However, few studies have been conducted to evaluate the effects of individual dietary soybean ANFs per se [7]. Recently, we reported a 6-week feeding trial in which rainbow trout fed a casein-based semipurified diet supplemented with soya saponin showed similar SBM-induced morphological changes in the epithelial cells of the distal intestine [8]. Moreover, fish fed a casein-based diet supplemented with a combination of soya saponin, soya isoflavone, Ca-phytate, saccharose, and soya lectin showed morphological changes of the lamina propria in the mucosal folds and submucosa as well, though fish fed a diet supplemented with either soya saponin or soya lectin alone did not show any morphological changes in this region [8].…”

Fatores antinutricionais da soja crua no crescimento e respostas hematológicas da tilápia do nilo

“…The study of the antinutritional factors in plant feed ingredients have gained more attention recently due to the markedly increase on plant feedstuffs inclusion in aquafeed in the last two decades. However, the substances which depress fish growth and health are difficult to study since most of the plant feedstuffs presents more than one antinutrient and showns that they may interact to produce undesirable effects (FRANCIS et al, 2001;IWASHITA et al, 2008;KROGDAHL et al, 2010).…”