title: Selection for high muscle fat in rainbow trout induces potentially higher chylomicron synthesis and PUFA biosynthesis in the intestine.
abstract: Two lines of rainbow trout divergently selected for muscle fat content, fat line (F) and lean line (L) were used to investigate the effect of genetic selection on digestion, intestinal nutrient transport and fatty acid bioconversion, in relation to dietary starch intake. This study involved a digestibility trial for 2 weeks using Cr(2)O(3) as inert marker, followed by a feeding trial for 4 weeks. For the entire duration, juvenile trout from the two lines were fed diets with or without gelatinized starch. Blood, pyloric ceca, midgut and hindgut were sampled at 24 h after the last meal. Transcripts of the proteins involved in nutrient transport and fatty acid bioconversion were abundant in the proximal intestine. GLUT2 transcripts were slightly higher in the F line ceca than in the L line. Dietary starch intake did not enhance the transcription of intestinal glucose transporters, SGLT1 and GLUT2; but it was associated with the higher expression of ApoA1 and PepT1 in the midgut. Significantly, the F line exhibited higher intestinal mRNA levels of MTP, ApoA4, Elovl2, Elovl5 and D6D than the L line, linked to chylomicron assembly and fatty acid bioconversion. Apparent digestibility coefficients of protein, lipid and starch were high in both lines, but not significantly different between them. In conclusion, we found a higher potential of chylomicron synthesis and fatty acid bioconversion in the intestine of F line, but no adaptive transcriptional response of glucose transporters to dietary starch and no genotypic differences in nutrient digestibility.
authors.affiliation: INRA, UR1067 Nutrition Metabolism Aquaculture, F-64310 Saint-Pée-sur-Nivelle, France.
authors.forename: Biju Sam
authors.initials: BS
authors.lastname: Kamalam
authors.forename: Stephane
authors.initials: S
authors.lastname: Panserat
authors.forename: Peyo
authors.initials: P
authors.lastname: Aguirre
authors.forename: Inge
authors.initials: I
authors.lastname: Geurden
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Fontagné-Dicharry
authors.forename: Françoise
authors.initials: F
authors.lastname: Médale
mesh_terms: D000273:Adipose Tissue / Q000254:growth & development / Q000378:metabolism; D000818:Animals; D002914:Chylomicrons / Q000096:biosynthesis; D004032:Diet; D004063:Digestion / Q000235:genetics / Q000502:physiology; D005231:Fatty Acids, Unsaturated / Q000096:biosynthesis*; D051273:Glucose Transporter Type 2 / Q000378:metabolism; D007413:Intestinal Mucosa / Q000378:metabolism; D009132:Muscles / Q000378:metabolism / Q000502:physiology; D017686:Oncorhynchus mykiss / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012641:Selection, Genetic; D051269:Sodium-Glucose Transporter 1 / Q000378:metabolism; D013213:Starch / Q000008:administration & dosage
chemical_list: D002914:Chylomicrons; D005231:Fatty Acids, Unsaturated; D051273:Glucose Transporter Type 2; D012333:RNA, Messenger; D051269:Sodium-Glucose Transporter 1; D013213:Starch