Effects of food restriction on growth, body composition and gene expression related in regulation of lipid metabolism and food intake in grass carp

It is well known that most fish would prefer to use body lipid stores for energy expenditure when receiving a long-term food restriction. However, the mechanism of this is still not clear. In the present study, a growth experiment was carried out to investigate the effects of food restriction on growth performance, gene expression related in regulation of lipid metabolism and food ingestion in grass carp (Ctenopharyngodon idellus). Four rations, satiation (S), 80% S, 60% S and 40% S, were adopted in this study. Each treatment was randomly assigned to triplicate net cages of 15 fish (177.3 +/- 3.3 g) per cage. The experiment lasted for 49 days at 30.0 +/- 3.0 degrees C. The experimental results showed that a significant increase in feeding rate and weight gain was found in grass carp with the increased ration level. The body lipid and energy content of the grass carp exhibited a significant decrease when receiving food restriction. The transcriptional levels of the genes involved in lipogenesis (srebp-1c, fas, ppar gamma) were down-regulated at the rations of food restriction. The relative expression of hepatic fas (fatty acid synthetase) and srebp-1c (sterol regulatory element-binding protein 1c) in the fish at satiation were significantly higher than the restricted-fed groups. Similarly, the expressions of hepatic ppar. (peroxisome proliferator-activated receptor-gamma) in the fish at the ration of satiation and 80% S were significantly higher than the group at the low ration of 40% S. However, the expression of hepatic cpt-1a (carnitine palmitoyl transferase I) involved in fatty acid beta-oxidation in fish was significantly up-regulated when receiving food restriction. Other hepatic lipolysis genes of ppar alpha (peroxisome proliferators-activated receptor alpha) and hl (hepatic lipase) didn&#39;t show any significant changes in restricted-fed fish. The transcriptional levels of hepatic leptin and hypothalamus pomc (proopiomelanocortin) were significantly down-regulated in fish fed with restricted rations. But the hypothalamus npy (neuropeptide Y) and lepr (leptin receptor) had no change. The present results indicated that a long-term food restriction could cause less accumulation of lipid and could be through a way of down-regulating lipogenesis genes and up-regulating lipolysis genes. Long-term restriction could also activate the appetite of grass carp by down-regulating some anorexigenic genes. Statement of relevance: Food restriction for some time could lead to a suitable lipid storage, in case of accumulation of fatty acid profile and lipid, in cultured grass carp. (C) 2016 Elsevier B.V. All rights reserved.</p

Resveratrol alleviates lipopolysaccharide-induced liver injury by inducing SIRT1/P62-mediated mitophagy in gibel carp (Carassius gibelio)

IntroductionResveratrol (RES) is a polyphenol organic compound with antioxidant and anti-inflammatory properties. This study aimed to determine whether and how RES can alleviate liver injury in lipopolysaccharide (LPS)-induced gibel carp.MethodsGibel carp were fed a diet with or without RES and were cultured for 8 weeks, followed by LPS injection.Results and discussionThe results suggested that RES attenuated the resulting oxidative stress and inflammation by activating the Nrf2/Keap1 pathway and inhibiting the NF-κB pathway, as confirmed by changes in oxidative stress, inflammation-related gene expression, and antioxidant enzyme activity. Furthermore, RES cleared damaged mitochondria and enhanced mitochondrial biogenesis to mitigate reactive oxygen species (ROS) accumulation by upregulating the SIRT1/PGC-1α and PINK1/Parkin pathways and reducing p62 expression. Overall, RES alleviated LPS-induced oxidative stress and inflammation in gibel carp through mitochondria-related mechanisms

Enhancement of liver mitochondrial complex I and energy metabolism induced by enteritis: The key role of gut microbiota derived endotoxins

publishedVersio

Effects of dietary lipid levels on growth, survival and lipid metabolism during early ontogeny of Pelteobagrus vachelli larvae

A feeding trial was conducted to investigate the effect of dietary lipid level on darkbarbel catfish (Pelteobagrus vachelli) larvae during ontogeny with regard to growth, survival and lipid utilization. Larvae were fed, from mouth opening to 20 days after hatching (DAH), with five isonitrogenous microdiets containing different lipid levels (58, 74, 111, 151 and 199 g kg(-1) diet). Live prey (newly hatched Artemia, unenriched) was used as the control diet. The activities of lipoprotein lipase (LPL), hepatic lipase (HL), pancreatic lipase (PL) and LPL gene expression at 3 DAH (mouth opening), 6 DAH, 11 DAH and 20 DAH were examined. The results showed that dietary lipid significantly affected survival and growth of darkbarbel catfish larvae. At the end of the feeding trial, larvae fed diets containing 111 to 151 g lipid kg(-1) had significantly higher survival. Specific growth rate (SGR) of larvae fed the diet containing the highest dietary lipid (199 g kg(-1)) was significantly (P<0.05) lower while no significant differences were observed among other groups fed formulated diets. LPL mRNA level generally increased first with increasing dietary lipid levels and then reached a plateau at different sampling ages. A similar pattern was observed for LPL activity only at 6 DAH and 20 DAH. High dietary lipid increased HL activity at 20 DAH. At 6 DAH, highest PL activity was observed at 199 g lipid kg(-1) diet. Higher dietary lipid resulted in earlier elevated activities of LPL, PL and HL The specific activities of the above three enzymes and LPL mRNA expression were detected at mouth opening and were significantly influenced by age. The activities of these enzymes increased first and then decreased or reached a plateau during development. The results suggest that dietary lipid could modify lipid utilization during ontogeny of darkbarbel catfish larvae. (C) 2009 Published by Elsevier B.V

Effects of different weaning strategies on survival and growth in Chinese longsnout catfish (Leiocassis longirostris Gunther) larvae

The effects of different weaning strategies during the larval rearing of Chinese longsnout catfish were determined in two trials. In the first trial, the effect of abrupt-weaning from live prey (Artemia nauplii) to micro-diet at 5, 6, 7, 8, 10 dph, respectively was investigated. The second trial examined the effect of weaning with co-feeding at different ages (6, 8 and 10 dph). The survival, growth, digestive enzymes, coefficient of variation of final body weight (CVFBW) and body length (CVBL), digestive enzyme activities, fish body lysozyme and fish body glucose were significantly influenced by abrupt-introducing of microdiet (P<0.05). When weaning with live prey, only the fish body lysozyme significantly increased in the group introduced to microdiet on 8 and 10 dph (P<0.05). The study showed that abrupt-weaning of Chinese longsnout catfish should be obtained after 10 dph. Co-feeding could reduce the stress to larvae and therefore the weaning could start at 6 dph with co-feeding. (C) 2012 Elsevier B.V. All rights reserved.The effects of different weaning strategies during the larval rearing of Chinese longsnout catfish were determined in two trials. In the first trial, the effect of abrupt-weaning from live prey (Artemia nauplii) to micro-diet at 5, 6, 7, 8, 10 dph, respectively was investigated. The second trial examined the effect of weaning with co-feeding at different ages (6, 8 and 10 dph)

Effects of Dietary Carbohydrate and Lipid Concentrations on Growth Performance, Feed Utilization, Glucose, and Lipid Metabolism in Two Strains of Gibel Carp

To test the hypothesis that effects of dietary carbohydrate and lipid concentrations on growth performance, feeding utilization, glucose and lipid metabolism in gibel carp A strain may be differ from F strain, these two strain of gibel carp were fed with one of three different isonitrogenous diets: HCLL (45% carbohydrate, 2% lipid), MCML (30% carbohydrate, 8% lipid), or LCHL (15% carbohydrate, 14% lipid). After 8 weeks, the HCLL-fed fish had the highest hepatosomatic index, hepatic crude lipid levels, and triglyceride levels and lipid retention efficiency. Enhanced lipogenesis and lipid uptake potential were observed in fish fed HCLL and MCML diets. Moreover, increases in glucose transport (glut2, P = 0.003) and glycolysis (gk, P = 0.012; 6pfk, P = 0.005) in livers of both strains were induced by the high-carbohydrate diet. Genotype-specific effect was identified on plasma lipid content. Plasma triglyceride levels were also greater in the F strain than in the A strain. Furthermore, the F strain had higher levels of fatty acid β-oxidation and glycolysis compared with the A strain. Nutrient retention was affected (P &lt; 0.05) by the interaction between genotype and diet, implied dietary carbohydrate played a vital role in lipid accumulation in gibel carp. As dietary lipids increased, the F strain exhibited better feed utilization and a higher PRE than the A strain. However, the A strain had better growth performance. Overall, the F strain had better glucose uptake, glycolysis potential, and lipid utilization ability than the A strain

Responses of yellow catfish (Pelteobagrus fulvidraco Richardson) exposed to dietary cyanobacteria and subsequent recovery

A 120-day toxicity experiment was conducted to investigate the effect of dietary cyanobacteria on the growth and liver histopathology of yellow catfish, and subsequent recovery when the fish were free of cyanobacteria. Three experimental diets were formulated: the control (cyanobacteria-free diet), low-cyanobacteria diet (LCD, 32.3 mu g microsystins/g) and high-cyanobacteria diet (HCD, 71.96 mu g microsystins/g). Each diet was fed to fish for 60 days and then all fish were free of cyanobacteria for a further 60 days. The results showed that a significant decrease in the specific growth rate (SGR) was observed in both fish fed with the LCD and HCD after a 1st 30-day exposure period, however, no significant difference in the SGR between the LCD and control groups was observed after a 2nd 30-day exposure period. At the end of the 60 days exposure, all examined liver tissues in both doses exhibited what appeared as dose-dependent histopathological modifications. After a 60-day recovery, there were no significant differences in the SGR among groups, while no obvious histopathological alteration was observed in livers of fish previously fed with the LCD. The results indicate that the LCD-treated fish have a full recovery after a 60-day recovery, but the HCD-treated fish did not. (C) 2012 Elsevier Ltd. All rights reserved.A 120-day toxicity experiment was conducted to investigate the effect of dietary cyanobacteria on the growth and liver histopathology of yellow catfish, and subsequent recovery when the fish were free of cyanobacteria. Three experimental diets were formulated: the control (cyanobacteria-free diet), low-cyanobacteria diet (LCD, 32.3 mu g microsystins/g) and high-cyanobacteria diet (HCD, 71.96 mu g microsystins/g). Each diet was fed to fish for 60 days and then all fish were free of cyanobacteria for a further 60 days

Dietary available phosphorus requirement for juvenile gibel carp (Carassius auratus gibelio var. CASIII)

A 57-day growth experiment was conducted with juvenile gibel carp (13.48 +/- 0.10g) in a flow-through system to study the effect of dietary phosphorus on growth performance, body composition, nutrition utilization, phosphorus loading and enzymes activities. Seven semipurifed diets were formulated to contain 0.07 (the basal), 2.27, 5.32, 8.10, 12.06, 15.24 and 19.48g available phosphorus/kg diet. The results showed that specific growth rate, body length and feed efficiency significantly increased in the fish fed diets containing 0.07 to 15.24g available P/kg diet (p&lt;.05). Ash and P content increased in fish fed diets containing 0.07-12.06P g/kg (p&lt;.05) and then levelled off, while moisture, crude protein and lipid had no significant difference (p&gt;.05). The protein retention efficiency increased in the fish fed with diets 0.07-5.32g/kg P (p&lt;.05) and then reached a plateau. The P content in faeces was higher in fish fed diets containing 15.24 and 19.48g available P/kg. Total P concentration in tank water increased in fish fed 0.07-12.06g available P per kg diet (p&lt;.05). The plasma P was higher in the fish fed with 15.24g available P/kg diet (p&lt;.05), triglycerides was lower in the fish fed diet containing 15.24 and 19.48g available P/kg (p&lt;.05), no significant differences were observed in plasma Ca, plasma glucose and calcitonin (p&gt;.05). Based on SGR, whole body P content and FE, dietary available P requirement for juvenile gibel carp were 13.37, 13.97 g/kg and 15.06 respectively