title: Bt-maize (MON810) and non-GM soybean meal in diets for Atlantic salmon (Salmo salar L.) juveniles--impact on survival, growth performance, development, digestive function, and transcriptional expression of intestinal immune and stress responses.
abstract: Responses in Atlantic salmon (Salmo salar L.) juveniles (fry) fed diets containing genetically modified maize (Bt-maize, MON810) expressing Cry1Ab protein from first-feeding were investigated during a 99-day feeding trial. Four experimental diets were made; each diet contained ∼20% maize, either Bt-maize or its near-isogenic maternal line (non-GM maize). One pair was fishmeal-based while the other pair included standard (extracted) soybean meal (SBM; 16.7% inclusion level), with the intention of investigating responses to the maize varieties in healthy fish as well as in immunologically challenged fish with SBM-induced distal intestinal inflammation, respectively. Three replicate tanks of fry (0.17±0.01 g; initial mean weight ± SEM) were fed one of the four diets and samples were taken on days 15, 36, 48 and 99. Survival, growth performance, whole body composition, digestive function, morphology of intestine, liver and skeleton, and mRNA expression of some immune and stress response parameters in the distal intestine were evaluated. After 99 days of feeding, survival was enhanced and the intended SBM-induced inflammatory response in the distal intestine of the two groups of SBM-fed fish was absent, indicating that the juvenile salmon were tolerant to SBM. Mortality, growth performance and body composition were similar in fish fed the two maize varieties. The Bt-maize fed fish, however, displayed minor but significantly decreased digestive enzyme activities of leucine aminopeptidase and maltase, as well as decreased concentration of gut bile salts, but significantly increased amylase activity at some sampling points. Histomorphological, radiographic and mRNA expression evaluations did not reveal any biologically relevant effects of Bt-maize in the gastrointestinal tract, liver or skeleton. The results suggest that the Cry1Ab protein or other compositional differences in GM Bt-maize may cause minor alterations in intestinal responses in juvenile salmon, but without affecting overall survival, growth performance, development or health.
authors.affiliation: Department of Basic Sciences and Aquatic Medicine, NMBU School of Veterinary Medicine, Norwegian University of Life Sciences (NMBU), Oslo, Norway.
authors.forename: Jinni
authors.initials: J
authors.lastname: Gu
authors.affiliation: Department of Basic Sciences and Aquatic Medicine, NMBU School of Veterinary Medicine, Norwegian University of Life Sciences (NMBU), Oslo, Norway.
authors.forename: Anne Marie
authors.initials: AM
authors.lastname: Bakke
authors.affiliation: Department of Basic Sciences and Aquatic Medicine, NMBU School of Veterinary Medicine, Norwegian University of Life Sciences (NMBU), Oslo, Norway.
authors.forename: Elin C
authors.initials: EC
authors.lastname: Valen
authors.affiliation: Nofima AS, Sunndalsøra, Norway.
authors.forename: Ingrid
authors.initials: I
authors.lastname: Lein
authors.affiliation: Department of Basic Sciences and Aquatic Medicine, NMBU School of Veterinary Medicine, Norwegian University of Life Sciences (NMBU), Oslo, Norway.
authors.forename: Åshild
authors.initials: Å
authors.lastname: Krogdahl
mesh_terms: D000821:Animal Feed / Q000032:analysis; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D017756:Aquaculture / Q000379:methods; D004032:Diet; D004063:Digestion / Q000502:physiology*; D030841:Food, Genetically Modified; D005786:Gene Expression Regulation / Q000276:immunology; D007107:Immune System / Q000378:metabolism; D007413:Intestinal Mucosa / Q000378:metabolism; D007422:Intestines / Q000276:immunology*; D030821:Plants, Genetically Modified; D020317:Salmo salar / Q000235:genetics / Q000254:growth & development* / Q000276:immunology / Q000502:physiology; D013025:Glycine max / Q000235:genetics; D013312:Stress, Physiological / Q000276:immunology; D003313:Zea mays / Q000235:genetics