关键词：
Oxidized fish oil;Nile tilapia;Myofiber;Lipidomics;Proteomics
摘要：
To investigate the effect of oxidized fish oil on fish muscle metabolic responses and flesh quality, Nile tilapia ( Oreochromis niloticus ) weighing 13.73 ± 0.31 g were fed two diets for 12 weeks: a fresh fish oil (FFO) and a highly oxidized fish oil (OFO) diet. The peroxide value of the FFO and OFO diets was 2.2 meq/kg and 120.6 meq/kg, respectively. The OFO diet resulted in a decrease in growth, muscularity, nutritional value of fatty acids in the muscle, and density of myofibers. In the OFO group, the mRNA expression levels of lipolysis genes including lipoprotein lipase ( lpl ) and hormone-sensitive lipase ( hsl ) in the muscle were upregulated compared with the FFO group, while, the mRNA expression level of acetyl CoA carboxylase was downregulated. Additionally, under the positive ion mode, the levels of DHA deposition in phosphatidylcholine and phosphatidyl ethanolamine were reduced in the muscle of the OFO group compared to the FFO group. A total of 68 proteins were identified in the muscle, of which 42 were up-regulated and 26 were down-regulated. The KEGG pathway enrichment analysis revealed that the major pathways of the differentially abundant proteins were the Wnt signaling pathway, TGF-beta signaling pathway, and proteoglycans in cancer. In summary, the OFO diet negatively affected growth, muscularity, and nutritional value. It also inhibited the transformation of myofiber types and led to the apoptosis of myofibers.
To investigate the effect of oxidized fish oil on fish muscle metabolic responses and flesh quality, Nile tilapia ( Oreochromis niloticus ) weighing 13.73 ± 0.31 g were fed two diets for 12 weeks: a fresh fish oil (FFO) and a highly oxidized fish oil (OFO) diet. The peroxide value of the FFO and OFO diets was 2.2 meq/kg and 120.6 meq/kg, respectively. The OFO diet resulted in a decrease in growth, muscularity, nutritional value of fatty acids in the muscle, and density of myofibers. In the OFO group, the mRNA expression levels of lipolysis genes including lipoprotein lipase ( lpl ) and hormone-sensitive lipase ( hsl ) in the muscle were upregulated compared with the FFO group, while, the mRNA expression level of acetyl CoA carboxylase was downregulated. Additionally, under the positive ion mode, the levels of DHA deposition in phosphatidylcholine and phosphatidyl ethanolamine were reduced in the muscle of the OFO group compared to the FFO group. A total of 68 proteins were identified in the muscle, of which 42 were up-regulated and 26 were down-regulated. The KEGG pathway enrichment analysis revealed that the major pathways of the differentially abundant proteins were the Wnt signaling pathway, TGF-beta signaling pathway, and proteoglycans in cancer. In summary, the OFO diet negatively affected growth, muscularity, and nutritional value. It also inhibited the transformation of myofiber types and led to the apoptosis of myofibers.
摘要：
Choline, an essential nutrient for aquatic animals, plays an important role in fish growth performance and health, but its effect on bighead carp is not yet known. To investigate the effects of choline chloride on growth performance, antioxidant properties, and intestinal function of juvenile bighead carp ( Aristichthys nobilis ), fish with an average weight of 1.77 ± 0.20 g were fed with different dietary choline chloride supplementation concentrations: 0 g/kg (control), 2, 4, 6, 8, and 10 g/kg for 66 days. The results indicated that dietary choline chloride supplementation at 6 g/kg improved the weight gain rate (WGR) and specific growth rate (SGR) ( p < 0.05). Dietary choline chloride supplementation (4–10 g/kg) decreased serum in serum triglycerides (TGs), total cholesterol (T-CHO), and glucose (GLU) levels of juvenile bighead carp ( p < 0.05). The malondialdehyde (MDA) level was significantly lower than the control group when choline chloride supplementation ranged from 6 to 10 g/kg. When choline chloride supplementation was at 6 g/kg, the activities of catalase (CAT) and superoxide dismutase (SOD) were significantly higher than the control group ( p < 0.05). The levels of choline chloride supplementation (6–10 g/kg) increased the activity of intestinal digestive enzymes and enhanced the intestinal digestibility of juvenile bighead carp ( p < 0.05). In addition, choline chloride levels did not affect the abundance of intestinal microbiota, and the composition of the dominant phylum genera was similar, including Ascomycetes, Actinobacteria, and thick-walled bacteria. At the genus level, there are Gemmobacter, ZOR0006, Peredibacter, and Mycobacterium, respectively. Overall, choline chloride supplementation (4–10 g/kg) could significantly improve the growth performance, antioxidant capacity, and digestive enzyme activity of juvenile bighead carp. Furthermore, broken-line regression analysis has identified 6.51 and 6.62 g/kg as the optimal levels of dietary choline chloride for juvenile bighead carp based on growth performance. Overall, appropriate dietary choline chloride could improve growth performance, antioxidant capacity, and intestinal function in bighead carp.
摘要：
This study was aimed to investigate whether eicosapentaenoic acid (EPA) and arachidonic acid (ARA), the representative n-3 or n-6 polyunsaturated fatty acids (PUFA), could alleviate enterotoxigenic Escherichia coli (ETEC) K88-induced inflammation and injury of intestinal porcine epithelial cells 1 (IPEC-1) by modulating pyroptosis and necroptosis signaling pathways. IPEC-1 cells were cultured with or without EPA or ARA in the presence or absence of ETEC K88. EPA and ARA reduced ETEC K88 adhesion and endotoxin content in the supernatant. EPA and ARA increased transepithelial electrical resistance (TEER) and decreased permeability of fluorescein isothiocyanate-labeled dextran (FD4), and increased membrane protein expression of occludin, ZO-1 and claudin-1, and relieved disturbed distribution of these proteins. EPA and ARA also reduced cell necrosis ratio. EPA or ARA reduced mRNA and concentration of tumor necrosis factor-α (TNF-α), interleukin (IL)-6 and IL-8, and decreased mRNA abundances of intestinal toll-like receptors 4 (TLR4) and its downstream signals. Moreover, EPA and ARA downregulated mRNA expression of nod-like receptor protein 3 (NLRP3), caspase 1 and IL-18, and inhibited protein expression of NLRP3, apoptosis-associated speck-like protein containing a CARD (ASC), gasdermin D and caspase-1. Finally, EPA and ARA reduced mRNA expression of fas-associated death domain protein (FADD), caspase 8, receptor interacting protein kinase (RIP) 1, mixed lineage kinase-like protein (MLKL), phosphoglycerate mutase 5 (PGAM5), motility related protein 1 (Drp1) and high mobility protein 1 (HMGB1), and inhibited protein expression of phosphorylated-RIP1 (p-RIP1), p-RIP3, p-MLKL and HMGB1. These data demonstrate that EPA and ARA prevent ETEC K88-induced cell inflammation and injury, which is partly through inhibiting pyroptosis and necroptosis signaling pathways.
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.
