scholarly journals Leucine sensing in rainbow trout hypothalamus is direct but separate from mTOR signalling in the regulation of food intake

Aquaculture ◽  
2021 ◽  
pp. 737009
Author(s):  
Sara Comesaña ◽  
Cristina Velasco ◽  
José L. Soengas
Keyword(s):  
Rainbow Trout ◽  
Food Intake ◽  
Mtor Signalling

scholarly journals Link between lipid metabolism and voluntary food intake in rainbow trout fed coconut oil rich in medium-chain TAG

2011 ◽  
Vol 107 (11) ◽  
pp. 1714-1725 ◽  
Author(s):  
A. Cláudia Figueiredo-Silva ◽  
Sadasivam Kaushik ◽  
Frédéric Terrier ◽  
Johan W. Schrama ◽  
Françoise Médale ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Rainbow Trout ◽  
Food Intake ◽  
Fatty Acid Synthase ◽  
Lipid Level ◽  
Coconut Oil ◽  
Mrna Levels ◽  
Medium Chain ◽  
Nutrient Utilisation ◽  
Voluntary Food Intake

We examined the long-term effect of feeding coconut oil (CO; rich in lauric acid, C12) on voluntary food intake and nutrient utilisation in rainbow trout (Oncorhynchus mykiss), with particular attention to the metabolic use (storage or oxidation) of ingested medium-chain TAG. Trout were fed for 15 weeks one of the four isoproteic diets containing fish oil (FO) or CO as fat source (FS), incorporated at 5 % (low fat, LF) or 15 % (high fat, HF). Fat level or FS did not modify food intake (g/kg0·8per d), despite higher intestinal cholecystokinin-T mRNA in trout fed the HF-FO diet. The HF diets relative to the LF ones induced higher growth and adiposity, whereas the replacements of FO by CO resulted in similar growth and adiposity. This, together with the substantial retention of C12 (57 % of intake), suggests the relatively low oxidation of ingested C12. The down-regulation of carnitine palmitoyl-transferase-1 (CPT-1) confirms the minor dependency of medium-chain fatty acids (MCFA) on CPT-1 to enter the mitochondria. However, MCFA did not up-regulate mitochondrial oxidation evaluated using hepatic hydroxyacyl-CoA dehydrogenase as a marker, in line with their high retention in body lipids. At a low lipid level, MCFA increased mRNA levels of fatty acid synthase, elongase and stearoyl-CoA desaturase in liver, showing the hepatic activation of fatty acid synthesis pathways by MCFA, reflected by increased 16 : 0, 18 : 0, 16 : 1, 18 : 1 body levels. The high capacity of trout to incorporate and transform C12, rather than to readily oxidise C12, contrasts with data in mammals and may explain the absence of a satiating effect of CO in rainbow trout.

Melatonin treatment alters glucosensing capacity and mRNA expression levels of peptides related to food intake control in rainbow trout hypothalamus

2012 ◽  
Vol 178 (1) ◽  
pp. 131-138 ◽  
Author(s):  
Marta Conde-Sieira ◽  
Marta Librán-Pérez ◽  
Marcos A. López Patiño ◽  
José L. Soengas ◽  
Jesús M. Míguez
Keyword(s):  
Rainbow Trout ◽  
Food Intake ◽  
Mrna Expression ◽  
Melatonin Treatment ◽  
Expression Levels ◽  
Mrna Expression Levels ◽  
Intake Control

scholarly journals Modulation of food intake by mTOR signalling in the dorsal motor nucleus of the vagus in male rats: focus on ghrelin and nesfatin-1

2013 ◽  
Vol 98 (12) ◽  
pp. 1696-1704 ◽  
Author(s):  
Weizhen Zhang ◽  
Chao Zhang ◽  
Danielle Fritze ◽  
Biaoxin Chai ◽  
Jiyao Li ◽  
...  
Keyword(s):  
Food Intake ◽  
Male Rats ◽  
Motor Nucleus ◽  
Dorsal Motor Nucleus ◽  
Mtor Signalling

scholarly journals Chronic cortisol and the regulation of food intake and the endocrine growth axis in rainbow trout

2015 ◽  
Vol 226 (2) ◽  
pp. 103-119 ◽  
Author(s):  
Barry N Madison ◽  
Sara Tavakoli ◽  
Sarah Kramer ◽  
Nicholas J Bernier
Keyword(s):  
Rainbow Trout ◽  
Food Intake ◽  
Mass Gain ◽  
Liver Glycogen ◽  
Mrna Levels ◽  
Muscle Lipid ◽  
Glucose Levels ◽  
Treated Fish ◽  
Plasma Gh ◽  
Post Implantation

To gain a better understanding of the mechanisms by which cortisol suppresses growth during chronic stress in fish, we characterized the effects of chronic cortisol on food intake, mass gain, the expression of appetite-regulating factors, and the activity of the GH/IGF axis. Fish given osmotic pumps that maintained plasma cortisol levels at ∼70 or 116 ng/ml for 34 days were sampled 14, 28 and 42 days post-implantation. Relative to shams, the cortisol treatments reduced food intake by 40–60% and elicited marked increases in liver leptin (lep-a1) and brain preoptic area (POA) corticotropin-releasing factor (crf) mRNA levels. The cortisol treatments also elicited 40–80% reductions in mass gain associated with increases in pituitarygh, liverghreceptor (ghr), liverigfIandigfbinding protein (igfbp)-1 and -2 mRNA levels, reduced plasma GH and no change in plasma IGF1. During recovery, while plasma GH and pituitarygh, liverghrandigfIgene expression did not differ between treatments, the high cortisol-treated fish had lower plasma IGF1 and elevated liverigfbp1mRNA levels. Finally, the cortisol-treated fish had higher plasma glucose levels, reduced liver glycogen and lipid reserves, and muscle lipid content. Thus, our findings suggest that the growth-suppressing effects of chronic cortisol in rainbow trout result from reduced food intake mediated at least in part by increases in liverlep-a1and POAcrfmRNA, from sustained increases in hepaticigfbp1expression that reduce the growth-promoting actions of the GH/IGF axis, and from a mobilization of energy reserves.

Correlating food intake and specific growth rate of rainbow trout of different sizes

Aquaculture ◽  
1992 ◽  
Vol 100 (1-3) ◽  
pp. 326
Author(s):  
I.D. McCarthy ◽  
C.G. Carter ◽  
D.F. Houlihan
Keyword(s):  
Growth Rate ◽  
Rainbow Trout ◽  
Food Intake ◽  
Specific Growth Rate ◽  
Specific Growth

CRF-related peptides contribute to stress response and regulation of appetite in hypoxic rainbow trout

2005 ◽  
Vol 289 (4) ◽  
pp. R982-R990 ◽  
Author(s):  
Nicholas J. Bernier ◽  
Paul M. Craig
Keyword(s):  
Rainbow Trout ◽  
Food Intake ◽  
Plasma Cortisol ◽  
Preoptic Area ◽  
Physiological Role ◽  
Corticotropin Releasing Factor ◽  
Stress Axis ◽  
Mrna Levels ◽  
Hypoxic Conditions ◽  
Hpi Axis

Hypoxia stress suppresses appetite in a variety of fish species, but the mechanisms mediating this response are not known. Therefore, given their anorexigenic and hypophysiotropic properties, we investigated the contribution of forebrain corticotropin-releasing factor (CRF) and urotensin I (UI) to the regulation of food intake and the hypothalamic-pituitary-interrenal (HPI) stress axis in hypoxic rainbow trout. Exposure to 50 and 35% O2 saturation for 24 h decreased food intake by 28 and 48%, respectively. The 35% O2 treatment also increased forebrain CRF and UI mRNA levels, plasma cortisol, and lactate. Exposure for 72 h to the same conditions resulted in similar reductions in food intake, increases in plasma cortisol proportional to the hypoxia severity, and increases in forebrain CRF and UI mRNA levels in the 50% O2 treatment. Relative to saline-infused fish, chronic intracranial infusion of the CRF receptor antagonist α-helical CRF(9–41) reduced the appetite-suppressing effects of 24-h exposure to 35% O2 and blocked the hypoxia-induced increase in plasma cortisol. Finally, forebrain microdissection revealed that 50 and 35% O2 exposure for 24 h specifically increases preoptic area CRF and UI mRNA levels in proportion to the severity of the hypoxic challenge and either has no effect or elicits small decreases in other forebrain regions. These results show that CRF-related peptides play a physiological role in regulating the HPI axis and in mediating at least a portion of the reduction in food intake under hypoxic conditions in rainbow trout and demonstrate that the response of forebrain CRF and UI neurons to this stressor is region specific.

scholarly journals Hypothalamic mechanisms linking fatty acid sensing and food intake regulation in rainbow trout

2017 ◽  
Vol 59 (4) ◽  
pp. 377-390 ◽  
Author(s):  
Cristina Velasco ◽  
Cristina Otero-Rodiño ◽  
Sara Comesaña ◽  
Jesús M Míguez ◽  
José L Soengas
Keyword(s):  
Fatty Acids ◽  
Transcription Factors ◽  
Fatty Acid ◽  
Rainbow Trout ◽  
Food Intake ◽  
Food Intake Regulation ◽  
Intake Regulation ◽  
First Time ◽  
Specific Inhibitors ◽  
Fatty Acid Sensing

We assessed in rainbow trout hypothalamus the effects of oleate and octanoate on levels and phosphorylation status of two transcription factors, FoxO1 and CREB, possibly involved in linking activation of fatty acid sensing with modulation of food intake through the expression of brain neuropeptides. Moreover, we assessed changes in the phosphorylation status of three proteins possibly involved in modulation of these transcription factors such as Akt, AMPK and mTOR. In a first experiment, we evaluated, in pools of hypothalamus incubated for 3 h and 6 h at 15°C in a modified Hanks’ medium containing 100 or 500 µM oleate or octanoate, the response of fatty acid sensing, neuropeptide expression and phosphorylation status of proteins of interest. The activation of fatty acid sensing and enhanced anorectic potential occurred in parallel with the activation of Akt and mTOR, and the inhibition of AMPK. The changes in these proteins would relate to a neuropeptide expression through changes in the phosphorylation status of transcription factors under their control, such as CREB and FoxO1, which displayed inhibitory (CREB) or activatory (FoxO1) responses when tissues were incubated with oleate or octanoate. In a second experiment, we incubated hypothalamus for 6 h with 500 µM oleate or octanoate alone or in the presence of specific inhibitors of Akt, AMPK, mTOR, CREB or FoxO1. The presence of inhibitors counteracted the effects of oleate or octanoate on the phosphorylation status of the proteins of interest. The results support, for the first time in fish, the involvement of these proteins in the regulation of food intake by fatty acids.

Sign in / Sign up

Export Citation Format

Share Document