Dietary starch promotes hepatic lipogenesis in barramundi (Lates calcarifer)

Barramundi (Lates calcarifer) are a highly valued aquaculture species, and, as obligate carnivores, they have a demonstrated preference for dietary protein over lipid or starch to fuel energetic growth demands. In order to investigate how carnivorous fish regulate nutritional cues, we examined the metabolic effects of feeding two isoenergetic diets that contained different proportions of digestible protein or starch energy. Fish fed a high proportion of dietary starch energy had a higher proportion of liver SFA, but showed no change in plasma glucose levels, and few changes in the expression of genes regulating key hepatic metabolic pathways. Decreased activation of the mammalian target of rapamycin growth signalling cascade was consistent with decreased growth performance values. The fractional synthetic rate (lipogenesis), measured by TAG 2H-enrichment using 2H NMR, was significantly higher in barramundi fed with the starch diet compared with the protein diet (0·6 (se 0·1) v. 0·4 (se 0·1) % per d, respectively). Hepatic TAG-bound glycerol synthetic rates were much higher than other closely related fish such as sea bass, but were not significantly different (starch, 2·8 (se 0·3) v. protein, 3·4 (se 0·3) % per d), highlighting the role of glycerol as a metabolic intermediary and high TAG-FA cycling in barramundi. Overall, dietary starch significantly increased hepatic TAG through increased lipogenesis. Compared with other fish, barramundi possess a unique mechanism to metabolise dietary carbohydrates and this knowledge may define ways to improve performance of advanced formulated feeds

Evaluation des rejets d'origine nutritionnelle par la methode des bilans, comparaison avec les flux sortants

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Effets de l'emploi de concentre proteique de soja sur l'activite d'enzymes de la trans-desamination chez la truite arc-en-ciel

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CHRONOLOGIE DE L'APPORT AZOTÉ PENDANT LE CYCLE DE REPRODUCTION CHEZ LA TRUIE

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Effets de l'habitat et de l'origine génétique sur les performances d'engraissement et la précocité sexuelle de jeunes truies de race Large White

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Dietary medium chain fatty acids from coconut oil have little effects on postprandial plasma metabolite profiles in rainbow trout (Oncorhynchus mykiss)

International audienceThis study examined the effect of dietary medium-chain triglycerides supplied by coconut oil on postprandial plasma metabolite profiles in rainbow trout. The fish (initial body weight 71.3 ± 0.3 g, 17 °C) were fed one of four practical diets containing either 5% fish oil (FO low-fat, FL), 15% fish oil (FO high-fat, FH), 5% coconut oil (CO low-fat, CL) or 15% coconut oil (CO high-fat, CH) for 3 weeks. At the end of the trial, the fish were weighed and plasma sampled to determine glucose, non-esterified fatty acids (NEFA), triglyceride (TG), cholesterol, high density lipoprotein-cholesterol (HDL-cholesterol), and myeloperoxidase (MPO) at 3, 6, 9, 12, 15 and 24 h after the last meal. Plasma total ketone bodies (KB) were determined at 6, 12 and 24 h after meal. Blood nitroblue tetrazolium (NBT) tests were also performed in samples withdrawn at 24 h after meal. Plasma glucose was higher in fish fed the low fat level diet than those fed high fat level, and peaked at postprandial 9–12 h. Fish fed CH showed higher plasma TG than CL at 3 h after meal, and there was no significant difference in plasma TG at the other time points. The peak of TG appeared 12 h after the meal. No clear pattern was found for cholesterol and HDL-cholesterol (HDL-C) in any of the groups. However, fish fed diet FH had the highest postprandial plasma HDL-cholesterol level and HDL-C/cholesterol ratio. The peak of NEFA was observed at 12–15 h after meal and plasma NEFA of fish fed CH was the highest. Plasma total KB decreased with postprandial time, and fish of FH groups had higher KB than that of CL group at 6 h. Besides, NBT in fish fed FH was significantly higher than that of CH, but there were no differences in MPO between groups. In summary, time-course changes in plasma profiles related to dietary fat level were as expected whereas those related to dietary fat source were relatively small

Regulation of de novo hepatic lipogenesis by insulin infusion in rainbow trout fed a high-carbohydrate diet

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Etude de la regulation nutritionnelle du metabolisme du glucose dans le foie de la truite arc-en-ciel (Oncorhynchus mykiss)

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Comparaison de l'utilisation des glucides alimentaires par la truite arc en ciel a 8 C et a 18 C

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