摘要：
Conjugated linoleic acid (CLA) has been shown to exhibit anti-inflammatory properties in the intestine in mammals. However, the effect of CLA on intestinal immune response in fish is still unknown. Therefore, a 65-day growth trial was conducted to investigate the effects of dietary conjugated linoleic acid (CLA) on morphology, selective immune parameters, and gene expressions in the intestine of grass carp. Seven isonitrogenous and isolipidic diets were formulated as follows: 0 (control), 0.5 (CLA0.5), 1 (CLA1), 1.5 (CLA1.5), 2 (CLA2), 2.5 (CLA2.5), and 3 (CLA3) g CLA per 100g of feed. RESULTS: showed that dietary supplementation of 1.5-3% CLA significantly (P<0.05) increased the fold and enterocyte heights in the PI and MI of grass carp. Complement 3 (C3) and immunoglobulin M (IgM) contents in three intestinal segments were significantly (P<0.05) higher in fish fed with CLA1.5 to CLA2.5 diets compared to fish fed the control diet. CLA1.5 to CLA2.5 diets significantly (P<0.05) increased the mRNA expression levels of anti-inflammatory cytokines (IL-10 and TGFbeta1) and significantly (P<0.05) reduced the mRNA expression levels of pro-inflammatory cytokines (IL-1beta, IL-8, and TNF-alpha) in the PI, MI, and DI. This improved expression of anti-inflammatory cytokines and the inhibited expression of pro-inflammatory cytokines in the intestine of grass carp, might be mediated via TLR4/NF-kappaB-signaling pathway. Our results suggested that CLA1.5 to CLA2 diets improved intestinal morphology, increased the expression of anti-inflammatory cytokines, and inhibited the expression of pro-inflammatory cytokines in the intestine of grass carp. In conclusion, dietary supplementation of 1.5%-2% CLA show the anti-inflammatory therapeutic potential in the intestine of grass carp. The anti-inflammatory therapeutic potential of CLA might be mediated via TLR4/NF-kappaB-signaling pathway.
摘要：
Yeast cell wall (YCW) preparations are important nutritional additives in the aquaculture industry. Head-kidney macrophages play important roles in innate immune functions in fish. However, the mechanisms underlying their stimulation are not yet characterized. The purpose of this study was to investigate the effects of YCW on immunological functions of channel catfish (Ictalurus punctatus) head-kidney macrophages. Our results showed that YCW preparations not only improved the proliferation and phagocytosis of macrophages but also induced the secretion of reactive oxygen species (ROS), nitric oxide (NO), inducible nitric oxide synthase (iNOS), and cytokines, such as tumor necrosis factor-alpha (TNF-alpha) and interleukin 1 beta (IL-1 beta). At a concentration of 500.0 mu g/mL, YCW preparations stimulated macrophage proliferation and phagocytosis to 1.98 and 1.8 times, respectively, when compared with the negative group. Equally, YCW preparations raised the production of NO by inducing iNOS and ROS in a concentration-dependent manner. Furthermore, these preparations enhanced TNF-alpha and IL-1 beta mRNA levels to multiple digits from 1.2 to 3.0 times, respectively. In conclusion, the stimulatory effects of YCW on the phagocytic activity of the fish macrophages were associated with respiratory bursts coupled with nitric oxide production.
摘要：
A 65‐day growth trial was conducted to investigate the effects of dietary conjugated linoleic acid (CLA) on growth performance, tissue adipocytokine levels and lipid metabolism of grass carp. Seven isonitrogenous and isolipidic diets were formulated as follows: 0 (control), 5 (CLA5), 10 (CLA10), 15 (CLA15), 20 (CLA20), 25 (CLA25) and 30 (CLA30) g/kg CLA. Results showed that incorporating as low as 25 g/kg CLA in the diet significantly decreased the growth of grass carp. The liver lipid content in fish fed with CLA15 to CLA30 significantly decreased. The leptin and resistin levels in liver of fish fed with CLA5 to CLA30 diets significantly increased. The mRNA expression levels of fatty acid synthase (FAS) and triacylglycerol lipase (TGL) in liver of fish fed with CLA5 to CLA30 and CLA10 to CLA30 diets also significantly decreased, respectively. In summary, the lipid‐lowering effects in grass carp liver were induced by the supplementation of 15–20 g/kg CLA, but its growth remained unaffected. Moreover, the lipid‐lowering effects of CLA on grass carp could also be modulated both by adipocytokine levels and by the expression of genes involved in lipid metabolism in tissues.
摘要：
Fish growth is an important index in aquaculture practice. However, the effect of growth under restricted feeding on quality of fish grown to the same size remains poorly unknown. In this study, yellow catfish were reared by feeding them at three different feeding rates such as low (FR-L group), medium (FR-M group) and high (apparent satiation) ration levels for 82, 58 and 34 days to reach the same size, respectively. After this period, the growth performance, whole-body amino acid composition and fatty acid profile of the fish were evaluated. Feeding restriction led to significant decreases in specific growth rate and feed conversion efficiency. Significant increases in dry matter, protein and energy contents were observed in fish under both restricted feeding treatments. FR-L-treated fish had significantly lower whole-body essential amino acid contents, and significantly higher Ala and non-essential amino acid contents compared to fish fed to satiation. Fish in restricted feeding treatments had significantly higher n-3 PUFA and n-3/n-6 ratio compared to the fish fed to satiation. The present results indicate that from a quality perspective, there are certain advantages in improvement of whole-body composition and enrichment of n-3 PUFA associated with the restricted feeding of yellow catfish at slow growth rate.
关键词：
animal;China;classification;isolation and purification;parasitology;Ranidae;rectum;scanning electron microscopy;species difference;stramenopile;symbiosis;ultrastructure;Animals;China;Microscopy, Electron, Scanning;Ranidae;Rectum;Species Specificity;Stramenopiles;Symbiosis
摘要：
Conjugated linoleic acid (CLA) has been shown to decrease body fat and increase lean tissue in mammals. However, limited data is available about the effect of CIA on the lipid content in fish tissue, and the mechanisms underlying the beneficial effects of CLA in fish are unknown. We hypothesized that dietary CIA may induce lipid-lowering effects in grass carp (Ctenopharyngodon idella) tissue, and the fat reduction effect was modulated by the expression of genes involved in the lipid metabolism. A 65-day growth trial was conducted to investigate the effect of CIA on the growth, tissue lipid deposition, and gene expression involved in the lipid metabolism of grass carp. Seven isonitrogenous and isolipidic diets were formulated: 0% CIA (control); 0.5% CIA (CLA0.5); 1% CIA (CLA1); 1.5% CIA (CLA1.5); 2% CIA (CLA2); 2.5% CIA (CLA25); and 3% CIA (CLA3). Results showed that only fish fed the CLA3 diet exhibited a significant reduction in feeding rate and specific growth rate than those of fish fed the control diet (P < 0.05). Significant decreases in the lipid content in the liver, intraperitoneal fat, and muscle were observed in fish fed with 2.5% to 3% CIA, 1.5% to 3% CIA, and 2% to 3% CIA diets, respectively (P<0.05), compared to those fed with the control diet. Dose- and tissue-dependent changes were found in the mRNA expressions of fatty acid synthetase (FAS), acetyl-CoA carboxylase (ACC), lipoprotein lipase (LPL), hormone-sensitive lipase (HSL), peroxisome proliferator-activated receptor alpha (PPAR alpha), peroxisome proliferator-activated receptor gamma (PPAR gamma), and sterol regulatory element binding protein-1c (SREBP-1c). The mRNA expressions in most of the genes examined in the liver, foregut, intraperitoneal fat and muscle were highly sensitive to dietary CIA. Our results suggested that a dose-dependent effect on the reduction of fish growth induced by CIA supplementation should be carefully considered in intensive aquaculture, although lipid reduction is nutritionally important for fatty liver control in grass carp. Furthermore, our results raise the possibility that the lipid-lowering effects of dietary CIA were modulated by the gene expressions in lipogenesis (such as FAS and ACC), lipoprotein transport (such as LPL), and lipolysis (such as HSL) primarily in the liver, foregut, intraperitoneal fat, and muscle. The activation of transcription factors (such as PPAR alpha, PPAR gamma, and SREBP-1c) may also be responsible for the lipid-lowering effects of dietary CIA (C) 2014 Elsevier B.V. All rights reserved.
