| 1 | Dietary n-3/n-6 polyunsaturated fatty acid ratio modulates growth performance in spotted seabass(Lateolabrax maculatus)through regulating lipid metabolism,hepatic antioxidant capacity and intestinal health显示文摘An 8-week feeding experiment was carried out to explore the effects of dietary n-3/n-6 polyunsaturated fatty acid(PUFA)ratio on growth performance,lipid metabolism,hepatic antioxidant status,and gut flora of spotted seabass(Lateolabrax maculatus).Six experimental diets were formulated to contain different levels of two purified oil sources including docosahexaenoic and eicosapentaenoic acids enriched oil(n-3)and linoleic acid-enriched oil(n-6)leading to n-3/n-6 PUFA ratios of 0.04,0.35,0.66,1.35,2.45 and16.17.Each diet was fed to triplicate groups of juvenile L.maculatus(11.06±0.20 g,30 fish/tank).Final body weight(FBW),weight gain(WG),specific growth rates(SGR),protein efficiency ratio(PER)and feed utilization efficiency increased as n-3/n-6 PUFA ratio increased up to a certain level,and then decreased thereafter.Fish fed the diet with n-3/n-6 PUFA ratio of 0.66 exhibited the highest FBW,WG,SGR and PER and the lowest feed conversion ratio.Lower n-3/n-6 PUFA ratios induced up-regulated expression of lipid synthesis-related genes(fas,acc2 and srebp-1c)and down-regulated expression of lipolysis related genes(atgl,ppara,cpt-1 and aox).Higher expression of lipolysis-related genes(atgl,ppara and cpt-1)was recorded at moderate n-3/n-6 PUFA ratios(0.66 to 1.35).Moreover,inappropriate n-3/n-6 PUFA ratios triggered up-regulation of pro-inflammatory genes(il-6 and tnf-a)and down-regulation of antiinflammatory genes(il-4 and il-10)in the intestine.The diet with n-3/n-6 PUFA ratio of 0.66 inhibited intestine inflammation,improved intestinal flora richness,increased the abundance of beneficial bacteria such as Lactobacillus,Alloprevotella and Ruminococcus,and reduced the abundance of harmful bacteria including Escherichia-Shigella and Enterococcus.In summary,it could be suggested that a dietary n-3/n-6PUFA ratio of 0.66 can improve growth performance and feed utilization in L.maculatus,as is deemed to be mediated through regulation of lipid metabolism and intestinal flora. | Yanzou Dong Yu Wei Ling Wang Kai Song Chunxiao Zhang Kangle Lu Samad Rahimnejad | 2023 | Animal Nutrition2023，，3： | 0 |
| 2 | Effects of dietary phosphorus level on growth,body composition,liver histology and lipid metabolism of spotted seabass(Lateolabrax maculatus)reared in freshwater显示文摘The present study was conducted to determine the effects of dietary phosphorus(P)levels on growth performance,body composition,liver histology and enzymatic activity,and expression of lipid metabolism-related genes in spotted seabass(Lateolabrax maculatus).Seven diets were prepared to contain available P levels of 0.48%(the control group),0.69%,0.89%,1.10%,1.28%,1.51%and 1.77%and feed fish(4.26±0.03 g)to satiety twice daily for 10 weeks.Significantly higher weight gain and specific growth rate were recorded at P levels of 0.69%-1.51%compared to the control group.Feed conversion ratio decreased with increasing P levels up to 0.89%and increased thereafter.The lowest liver lipid content,viscerosomatic index and lipid content of whole-body were obtained in the 0.89%-P group among dietary treatments.P and calcium(Ca)contents in whole body were increased,while liver triglyceride and cholesterol contents were decreased with increasing dietary P levels from 0.48%to 1.77%.The highest activity of hepatic lipase was recorded in the 1.10%-P group among dietary treatments.Compared to the control group,1.10%P enhanced the proportion of HUFA and reduced the proportion of SFA and MUFA.The histological observations showed that P deficiency(0.48%)led to the vacuolization of hepatocytes and increased number of lipid droplets.Meanwhile,overall liver tissue structure was improved when P level increased to 1.28%.Compared to the control group,expression of lipid metabolism-related genes such as FAS,ACC-2 and SREBP-1 was decreased at 0.89%-1.10%P group while an opposite trend was observed in the expression of PPARa2 and CPT-1 genes.The current study showed that 0.89%dietary P levels could promote growth performance of spotted seabass and reduce lipid accumulation in the liver.A broken-line regression analysis based on weight gain showed that the optimum dietary P level(available P)for juvenile spotted seabass reared in freshwater was 0.72%. | Jilei Zhang Shuwei Zhang Kangle Lu Ling Wang Kai Song Xueshan Li Chunxiao Zhang Samad Rahimnejad | 2023 | Aquaculture and Fisheries2023，8，5： | 0 |
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