Influence of dietary soy protein and peptide products on bile acid status and distal intestinal morphology of rainbow trout Oncorhynchus mykiss

• Published in: Fisheries science Vol. 78; no. 6; pp. 1273 - 1283
• Main Authors: Yamamoto, Takeshi, Murashita, Koji, Matsunari, Hiroyuki, Sugita, Tsuyoshi, Furuita, Hirofumi, Iwashita, Yasuro, Amano, Shunji, Suzuki, Nobuhiro
• Format: Journal Article
• Language: English
• Published: Japan Springer Japan 01.11.2012; Springer Nature B.V
• Subjects: Amino acids; Aquaculture; Bile; Biomedical and Life Sciences; Diet; Fish; Fish & Wildlife Biology & Management; Fisheries; Fishery sciences; Food Science; Freshwater & Marine Ecology; Gallbladder; Ingredients; Laboratories; Life Sciences; Lipids; Morphology; Oncorhynchus mykiss; Original Article; Peptides; Physical growth; Proteins; Salmon; Soy products; Soybeans; Studies; Syrups & sweeteners; Trout; Distal intestine; Bile acid; Soy peptide; Soya saponin; Soybean meal
• ISSN: 0919-9268; 1444-2906
• DOI: 10.1007/s12562-012-0551-z

To investigate the influence of dietary soy protein size on the bile acid status and the distal intestinal morphology in rainbow trout Oncorhynchus mykiss , diets based on soybean meal (SBM), soy protein isolate (SPI) and 4 soy peptide products having different molecular sizes were fed to trout (initial BW, 19 g) for 10 weeks. A diet based on fish meal (Cont) and a diet including the smallest-peptide and low-saponin product (Hi-Nute AM) and supplemented with soya saponin (AMS) were also fed. In fish fed diets SBM and SPI, the gallbladder was atrophied, the proportion of biliary cholyltaurine decreased, and highly vacuolated epithelial cells of mucosal folds and proliferation of connective tissues in the submucosa of the distal intestine were observed. These parameters tended to improve in fish fed soy peptide diets and especially those of fish fed diet AM were similar to fish fed diet Cont. Although the gallbladder of fish fed diet AMS was smaller than fish fed the unsupplemented diet AM, no morphological abnormalities were observed in the distal intestine. These results suggest that soy proteins/peptides with relatively large sizes and with soya saponin affect the bile acid status and distal intestinal morphology of rainbow trout.