title: Postprandial nutrient-sensing and metabolic responses after partial dietary fishmeal replacement by soyabean meal in turbot (Scophthalmus maximus L.).
abstract: In this study, we chose a carnivorous fish, turbot (Scophthalmus maximus L.), to examine its nutrient-sensing and metabolic responses after ingestion of diets with fishmeal (FM), or 45% of FM replaced by soyabean meal (34·6% dry diet) balanced with or without essential amino acids (EAA) to match the amino acid profile of FM diet for 30 d. After a 1-month feeding trial, fish growth, feed efficiency and nutrient retention were markedly reduced by soyabean meal-incorporated (SMI) diets. Compared with the FM diet, SMI led to a reduction of postprandial influx of free amino acids, hypoactivated target of rapamycin signalling and a hyperactivated amino acid response pathway after refeeding, a status associated with reduced protein synthesis, impaired postprandial glycolysis and lipogenesis. These differential effects were not ameliorated by matching an EAA profile of soyabean meal to that of the FM diet through dietary amino acid supplementation. Therefore, this study demonstrated that the FM diet and SMI diets led to distinct nutrient-sensing responses, which in turn modulated metabolism and determined the utilisation efficiency of diets. Our results provide a new molecular explanation for the role of nutrient sensing in the inferior performance of aquafeeds in which FM is replaced by soyabean meal.
authors.affiliation: The Key Laboratory of Aquanutrition,Ocean University of China,Qingdao 266003,People's Republic of China.
authors.forename: Dandan
authors.initials: D
authors.lastname: Xu
authors.affiliation: The Key Laboratory of Aquanutrition,Ocean University of China,Qingdao 266003,People's Republic of China.
authors.forename: Gen
authors.initials: G
authors.lastname: He
authors.affiliation: The Key Laboratory of Aquanutrition,Ocean University of China,Qingdao 266003,People's Republic of China.
authors.forename: Kangsen
authors.initials: K
authors.lastname: Mai
authors.affiliation: The Key Laboratory of Aquanutrition,Ocean University of China,Qingdao 266003,People's Republic of China.
authors.forename: Huihui
authors.initials: H
authors.lastname: Zhou
authors.affiliation: The Key Laboratory of Aquanutrition,Ocean University of China,Qingdao 266003,People's Republic of China.
authors.forename: Wei
authors.initials: W
authors.lastname: Xu
authors.affiliation: The Key Laboratory of Aquanutrition,Ocean University of China,Qingdao 266003,People's Republic of China.
authors.forename: Fei
authors.initials: F
authors.lastname: Song
mesh_terms: D000601:Amino Acids, Essential / Q000008:administration & dosage / Q000097:blood; D000821:Animal Feed / Q000032:analysis; D000818:Animals; D004032:Diet / Q000662:veterinary*; D004044:Dietary Proteins / Q000008:administration & dosage; D005412:Flatfishes; D062407:Meals; D019518:Postprandial Period; D013025:Glycine max
chemical_list: D000601:Amino Acids, Essential; D004044:Dietary Proteins
keywords: AAR amino acid response; B0AT1
                  B0-type amino acid transporter 1; EAA essential amino acids; FM fishmeal; Fishmeal; Metabolism; Nutrient sensing; PepT1
                  peptide transporter 1; S6 ribosomal protein S6; SMI soyabean meal-incorporated diet; SMI+AA SMI diet with dietary EAA supplementation; SNAT2
                  sodium-coupled neutral amino acid transporter 2; Soyabean meal; TOR target of rapamycin; Turbot; eIF2α eukaryotic initiation factor 2 α; y+LAT1
                  y+L-type amino acid transporter 1