Hepatic fatty acid biosynthesis is more responsive to protein than carbohydrate in rainbow trout during acute stimulations.
The link between dietary carbohydrate/protein and de novo lipogenesis (DNL) remains debatable in carnivorous fish. We aimed to evaluate and compare the response of hepatic lipogenic gene expression to dietary carbohydrate intake/glucose and dietary protein intake/amino acids (AAs) during acute stimulations using both in vivo and in vitro approaches. For the in vivo trial, three different diets and a controlled-feeding method were employed to supply fixed amount of dietary protein or carbohydrate in a single meal; for the in vitro trial, primary hepatocytes were stimulated with a low or high level of glucose (3 mM or 20 mM) and a low or high level of AAs (one-fold or four-fold concentrated AAs). In vitro data showed that a high level of AAs upregulated the expression of enzymes involved in DNL [fatty acid synthase (FAS) and ATP citrate lyase (ACLY)], lipid bioconversion [elongation of very long chain fatty acids like-5 (Elovl5), Elovl2, Δ6 fatty acyl desaturase (D6D) and stearoyl-CoA desaturase-1 (SCD1)], NADPH production [glucose-6-phosphate dehydrogenase (G6PDH) and malic enzyme (ME)], and transcriptional factor sterol regulatory element binding protein 1-like, while a high level of glucose only elevated the expression of ME. Data in trout liver also showed that high dietary protein intake induced higher lipogenic gene expression (FAS, ACLY, and Elovl2) regardless of dietary carbohydrate intake, while high carbohydrate intake markedly suppressed the expression of acetyl-CoA carboxylase (ACC) and Elovl5. Overall, we conclude that, unlike rodents or humans, hepatic fatty acid biosynthetic gene expression in rainbow trout is more responsive to dietary protein intake/AAs than dietary carbohydrate intake/glucose during acute stimulations. This discrepancy probably represents one important physiological and metabolic difference between carnivores and omnivores.
Institut National de la Recherche Agronomique, UR 1067 Nutrition Métabolisme, Aquaculture, Aquapôle, CD 918, Saint-Pée-sur-Nivelle, France.
Weiwei
W
Dai
Institut National de la Recherche Agronomique, UR 1067 Nutrition Métabolisme, Aquaculture, Aquapôle, CD 918, Saint-Pée-sur-Nivelle, France.
Stéphane
S
Panserat
Institut National de la Recherche Agronomique, UR 1067 Nutrition Métabolisme, Aquaculture, Aquapôle, CD 918, Saint-Pée-sur-Nivelle, France.
Sadasivam
S
Kaushik
Institut National de la Recherche Agronomique, UR 1067 Nutrition Métabolisme, Aquaculture, Aquapôle, CD 918, Saint-Pée-sur-Nivelle, France.
Frédéric
F
Terrier
Institut National de la Recherche Agronomique, UR 1067 Nutrition Métabolisme, Aquaculture, Aquapôle, CD 918, Saint-Pée-sur-Nivelle, France.
Elisabeth
E
Plagnes-Juan
Institut National de la Recherche Agronomique, UR 1067 Nutrition Métabolisme, Aquaculture, Aquapôle, CD 918, Saint-Pée-sur-Nivelle, France.
Iban
I
Seiliez
Institut National de la Recherche Agronomique, UR 1067 Nutrition Métabolisme, Aquaculture, Aquapôle, CD 918, Saint-Pée-sur-Nivelle, France skiba@st-pee.inra.fr.
Sandrine
S
Skiba-Cassy
D000596:Amino Acids / Q000378:metabolism; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D002478:Cells, Cultured; D004040:Dietary Carbohydrates / Q000008:administration & dosage / Q000378:metabolism*; D004044:Dietary Proteins / Q000008:administration & dosage / Q000378:metabolism*; D005227:Fatty Acids / Q000096:biosynthesis*; D029941:Fish Proteins / Q000235:genetics / Q000378:metabolism; D015971:Gene Expression Regulation, Enzymologic; D005947:Glucose / Q000378:metabolism; D022781:Hepatocytes / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D007328:Insulin / Q000378:metabolism; D050155:Lipogenesis / Q000187:drug effects / Q000235:genetics; D000076222:Mechanistic Target of Rapamycin Complex 1; D046912:Multiprotein Complexes / Q000378:metabolism; D009752:Nutritional Status; D017686:Oncorhynchus mykiss / Q000235:genetics / Q000378:metabolism*; D061251:Primary Cell Culture; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D015398:Signal Transduction; D020123:Sirolimus / Q000494:pharmacology; D058570:TOR Serine-Threonine Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D013997:Time Factors
D000596:Amino Acids; D004040:Dietary Carbohydrates; D004044:Dietary Proteins; D005227:Fatty Acids; D029941:Fish Proteins; D007328:Insulin; D046912:Multiprotein Complexes; D047428:Protein Kinase Inhibitors; D000076222:Mechanistic Target of Rapamycin Complex 1; D058570:TOR Serine-Threonine Kinases; D005947:Glucose; D020123:Sirolimus
carbohydrate; fatty acid biosynthesis; lipogenesis; protein; rainbow trout; target of rapamycin