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| 1 | Dietary cholesterol promotes growth and ecdysone signalling pathway by modulating cholesterol transport in swimming crabs(Portunus trituberculatus)显示文摘Cholesterol,as an indispensable nutrient,regulates molting and growth in crustacean.As crustaceans are unable to biosynthesize cholesterol de novo,it is central to understand how dietary cholesterol affects molting in crustaceans.An 8-week feeding trial was conducted to evaluate the effects of dietary cholesterol level(0.12%,0.43%,0.79%,1.00%,1.30%and 2.50%)on growth,cholesterol metabolism and expression of genes related to lipid and ecdysone metabolism in female swimming crabs(Portunus trituberculatus).A total of 192 crabs(1.41±0.05 g)were randomly distributed into 192 aquaria.Each treatment had 4 replicates with each replicate containing 8 crabs.Crabs fed the 1.00%cholesterol diet showed best growth performance,and thus based on percent weight gain,the optimal dietary cholesterol requirement was calculated at 1.01%.Tissue cholesterol concentrations were positively correlated with dietary cholesterol level.The contents of functional fatty acids in hepatopancreas significantly increased as dietary cholesterol increased from 0.12%to 2.50%(P<0.05).The expression levels of genes related to lipogenesis pathway,lipid catabolism and fatty acid oxidation were significantly downregulated with increased dietary cholesterol level(P<0.05).The highest expression levels of cholesterol transport genes,low-density lipoprotein receptor(ldlr)and low-density lipoprotein receptorrelated protein 2(lrp2)occurred in crabs fed the 1.30%cholesterol diet.Moreover,hormones related to molting such as crustacean hyperglycemic hormone(CHH),methyl farnesoate(MF),molt-inhibiting hormone(MIH),and ecdysone in hemolymph were significantly influenced by dietary cholesterol level(P<0.05).The highest expression levels of ecdysone receptor(ecr)and chitinase 1(chi1)in eyestalk and hepatopancreas were found in crabs fed the diet containing 1.00%cholesterol(P<0.05).In conclusion,the optimal dietary level was beneficial to functional fatty acid accumulation,regulated lipid metabolism,promoted the ecdysone signalling pathway by improving the cholesterol transport,and improved the molting rate and growth of swimming crabs. | Tingting Zhu Qicun Zhou Zheng Yang Yingying Zhang Jiaxiang Luo Xiangsheng Zhang Yuedong Shen Lefei Jiao Douglas R.Tocher Min Jin | 2022 | Animal Nutrition2022,,3: | 1 |
| 2 | High dietary lipid level promotes low salinity adaptation in the marine euryhaline crab(Scylla paramamosain)显示文摘The physiological processes involved in adaptation to osmotic pressure in euryhaline crustaceans are highly energy demanding,but the effects of dietary lipids(fat)on low salinity adaptations have not been well evaluated.In the present study,a total of 120 mud crabs(Scylla paramamosain,BW=17.87±1.49 g)were fed control and high-fat(HF)diets,at both medium salinity(23‰)and low salinity(4‰)for 6 wk,and each treatment had 3 replicates with each replicate containing 10 crabs.The results indicated that a HF diet significantly mitigated the reduction in survival rate,percent weight gain and feed efficiency induced by low salinity(P<0.05).Low salinity lowered lipogenesis and activated lipolysis resulting in lipid depletion in the hepatopancreas of mud crabs(P<0.05).Thus,HF diets enhanced the process of lipolysis to supply more energy.In the gills,low salinity and the HF diet increased the levels of mitochondrial biogenesis markers,the activity of mitochondrial complexes,and the expression levels of genes related to energy metabolism(P<0.05).Consequently,the positive effects of the HF diet on energy metabolism in mud crabs at low salinity promoted osmotic pressure regulation.Specifically,significantly higher haemolymph osmotic pressure and inorganic ion content,as well as higher osmotic pressure regulatory enzyme activity in gills,and gene and protein expression levels of NaK-ATPase were observed in crabs fed the HF diet at low salinity(P<0.05).In summary,high dietary lipid levels improved energy provision to facilitate mitochondrial biogenesis,which increased ATP provision for osmotic pressure regulation of mud crabs.This study also illustrates the importance of dietary lipid nutrition supplementation for low salinity adaptations in mud crabs. | Jiaxiang Luo Chen Ren Tingting Zhu Chen Guo Shichao Xie Yingying Zhang Zheng Yang Wenli Zhao Xiangsheng Zhang Jingjing Lu Lefei Jiao Qicun Zhou Douglas R.Tocher Min Jin | 2023 | Animal Nutrition2023,,1: | 0 |
| 3 | Dietary choline activates the Ampk/Srebp signaling pathway and decreases lipid levels in Pacific white shrimp(Litopenaeus vannamei)显示文摘An 8-week feeding trial was conducted in Pacific white shrimp(Litopenaeus vannamei)to evaluate the effects of dietary choline supplementation on choline transport and metabolism,hepatopancreas histological structure and fatty acid profile,and regulation of lipid metabolism.Six isonitrogenous and isolipidic diets were formulated to contain different choline levels of 2.91(basal diet),3.85,4.67,6.55,10.70 and 18.90 g/kg,respectively.A total of 960 shrimp(initial weight,1.38±0.01 g)were distributed randomly into twenty-four 250-L cylindrical fiber-glass tanks,with each diet assigned randomly to 4replicate tanks.The results indicated that dietary choline significantly promoted the deposition of choline,betaine and carnitine(P<0.05).The diameters and areas of R cells,total lipid and triglyceride contents in hepatopancreas,and triglyceride and non-esterified fatty acid contents in hemolymph were negatively correlated with dietary choline level.The contents of functional fatty acids in hepatopancreas,the activity of acetyl-CoA carboxylase(Acc),and the mRNA expression of fas,srebp and acc were highest in shrimp fed the diet containing 4.67 g/kg choline,and significantly higher than those fed the diet containing 2.91 g/kg,the lowest level of choline(P<0.05).The number of R cells,content of very lowdensity lipoprotein(VLDL),activities of carnitine palmitoyl-transferase(Cpt1),lipoprotein lipase and hepatic lipase,and the mRNA expression levels of cpt1,fabp,fatp,ldlr,and ampk in hepatopancreas increased significantly as dietary choline increased(P<0.05).In addition,hepatopancreas m RNA expression levels of ctl1,ctl2,oct1,badh,bhmt,ck,cept,and cct were generally up-regulated as dietary choline level increased(P<0.01).In conclusion,dietary choline promoted the deposition of choline and its metabolites by up-regulating genes related to choline transport and metabolism.Moreover,appropriate dietary choline level promoted the development of hepatopancreas R cells and maintained the normal accumulation of lipids required for development,while high dietary choline not only promoted hepatopancreas lipid export by enhancing VLDL synthesis,but also promoted fatty acidβ-oxidation and inhibited de novo fatty acid synthesis by activating the Ampk/Srebp signaling pathway.These findings provided further insight and understanding of the mechanisms by which dietary choline regulated lipid metabolism in L.vannamei. | Jingjing Lu Xinyue Tao Jiaxiang Luo Tingting Zhu Lefei Jiao Peng Sun Qicun Zhou Douglas R.Tocher Min Jin | 2023 | Animal Nutrition2023,,4: | 0 |