Digestive function and intestinal integrity in Atlantic salmon ( Salmo salar) fed kernel meals and protein concentrates made from yellow or narrow-leafed lupins

• Published in: Aquaculture Vol. 261; no. 4; pp. 1382 - 1395
• Main Authors: Refstie, Ståle, Glencross, Brett, Landsverk, Thor, Sørensen, Mette, Lilleeng, Einar, Hawkins, Wayne, Krogdahl, Åshild
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 11.12.2006; Elsevier Science; Elsevier Sequoia S.A
• Subjects: Agnatha. Pisces; anadromous fish; Animal aquaculture; animal morphology; Animal productions; Bile acids; Biological and medical sciences; blood chemistry; blood plasma; Diet; digestibility; digestible energy; Digestive system; enzyme activity; feed composition; fish culture; Fish feed; fish feeding; Fundamental and applied biological sciences. Psychology; gastrointestinal integrity; General aspects; Histology; histopathology; Kernel meal; Leucine aminopeptidase; Lupin; Lupinus angustifolius; Lupinus luteus; Maltase; mariculture; Marine; microvilli; Pellet quality; plant proteins; plant source protein; Plasma chemistry; Protein concentrate; protein content; Proteins; Salmo salar; Salmon; seeds; Soybean; stomach ulcers; Studies; Triticum aestivum; Trypsin; Vertebrates: general zoology, morphology, phylogeny, systematics, cytogenetics, geographical distribution; Trypsin; Leucine aminopeptidase; Pellet quality; Bile acids; Lupin; Maltase; Histology; Soybean; Protein concentrate; Kernel meal; Fish feed; Plasma chemistry; Pellet; Leucyl aminopeptidase; Blood plasma; Dicotyledones; Pisces; Quality; Angiospermae; Salmonidae; Serine endopeptidases; Enzyme; Aminopeptidases; Salmo salar; Plant leaf; Glycine max; Protein; Peptidases; Vertebrata; Leguminosae; α-Glucosidase; Glycosidases; Hydrolases; Spermatophyta; O-Glycosidases; Aquaculture; Bile
• ISSN: 0044-8486; 1873-5622
• DOI: 10.1016/j.aquaculture.2006.07.046

This study assessed the effects of yellow lupin ( Lupinus luteus) and narrow-leafed lupin ( L. angustifolius) kernel meals and protein concentrates on the gastrointestinal integrity, capacity for digestive hydrolysis, and digestibility of nutrients in Atlantic salmon. A basal diet (FM) was made from fish meal, wheat, and fish oil. Six additional diets were formulated by replacing 30% of the FM diet with lupin kernel meal made from L. l. cv. Wodjil (LKM), L. a. cv. Belara (BKM), and L. a. cv. Myallie (MKM), lupin protein concentrates made from the same L. l. (LPC) and L. a. cv. M (MPC), or extracted soybean meal (SBM). All diets were extruded. Each diet was fed to three groups of 176 g salmon kept in 1 m 2 tanks with 5.6 °C saltwater for 3 weeks prior to sampling of blood, intestinal organs, digesta, and faeces. Inclusion of lupin meals in the diets resulted in harder and more condensed feed particles. Ulcer-like lesions were observed in the stomach of fish from all feeding groups, and this was worsened by lupin in the diet, but did not appear to be pellet hardness related. No consistent altered morphology was observed in the distal intestine (DI) of fish fed the FM and lupin diets, while the DI of fish fed SBM showed consistent and typical soybean meal-induced pathomorphological changes. Plasma cholesterol was higher when feeding MKM and LKM than when feeding FM, MPC, and LPC, with intermediate levels when feeding BKM and SBM. Feeding LKM and LPC resulted in a higher weight of the GIT when related to body weight. Trypsin activity and bile acid concentration were generally higher in digesta from the pyloric (PI) and mid (MI) intestine when feeding FM and lupin diets than when feeding SBM, while the opposite was seen for trypsin activity in digesta from DI. There were no effects of diet on leucine aminopeptidase (LAP) and maltase activity in PI and MI, but in DI the activity of these brush border enzymes were significantly lowered when feeding SBM. SBM in the diet resulted in watery faeces and lowered apparent digestibility of lipid, but this was not observed when feeding the lupin diets. To conclude, the tested lupin kernel meals and protein concentrates did not alter the intestinal function in Atlantic salmon when included at 30% of the diet. Dietary lupin was, however, involved in the worsening of ulcer-like gastric lesions.