Background High dietary carbohydrates can spare protein in rainbow trout(Oncorhynchus mykiss)but may affect growth and health.Inulin,a prebiotic,could have nutritional and metabolic effects,along with anti-inflammator...Background High dietary carbohydrates can spare protein in rainbow trout(Oncorhynchus mykiss)but may affect growth and health.Inulin,a prebiotic,could have nutritional and metabolic effects,along with anti-inflammatory properties in teleosts,improving growth and welfare.We tested this hypothesis in rainbow trout by feeding them a 100%plant-based diet,which is a viable alternative to fishmeal and fish oil in aquaculture feeds.In a two-factor design,we examined the impact of inulin(2%)as well as the variation in the carbohydrates(CHO)/plant protein ratio on rainbow trout.We assessed the influence of these factors on zootechnical parameters,plasma metabolites,gut microbiota,production of short-chain fatty acids and lactic acid,as well as the expression of free-fatty acid receptor genes in the mid-intestine,intermediary liver metabolism,and immune markers in a 12-week feeding trial.Results The use of 2%inulin did not significantly change the fish intestinal microbiota,but interestingly,the high CHO/protein ratio group showed a change in intestinal microbiota and in particular the beta diversity,with 21 bacterial genera affected,including Ralstonia,Bacillus,and 11 lactic-acid producing bacteria.There were higher levels of butyric,and valeric acid in groups fed with high CHO/protein diet but not with inulin.The high CHO/protein group showed a decrease in the expression of pro-inflammatory cytokines(il1b,il8,and tnfa)in liver and a lower expression of the genes coding for tight-junction proteins in mid-intestine(tjp1a and tjp3).However,the 2%inulin did not modify the expression of plasma immune markers.Finally,inulin induced a negative effect on rainbow trout growth performance irrespective of the dietary carbohydrates.Conclusions With a 100%plant-based diet,inclusion of high levels of carbohydrates could be a promising way for fish nutrition in aquaculture through a protein sparing effect whereas the supplementation of 2%inulin does not appear to improve the use of CHO when combined with a 100%plant-based diet.展开更多
Juvenile rainbow trout Oncorhynchus mykiss were subjected to one of four treatments in a two-by-two experimental design: 1) fed at a density of 1.8 g/m<sup>3</sup>, 2) Fasted at 1.8 g/m<sup>3</sup...Juvenile rainbow trout Oncorhynchus mykiss were subjected to one of four treatments in a two-by-two experimental design: 1) fed at a density of 1.8 g/m<sup>3</sup>, 2) Fasted at 1.8 g/m<sup>3</sup>, 3) fed at 30.1 g/m<sup>3</sup>, and 4) fasted at 30.1 g/m<sup>3</sup>. Blood glucose and hematocrit were measured at 4, 6, 48, 168, and 336 hours after placement in one of the two rearing densities, with relative fin lengths and organosomatic indices recorded at 336 hours. Glucose levels over time were not significantly different among the density and feeding treatments. Hematocrit levels over time were also not significantly different. Total lengths, weight, hepatosomatic index, viscerosomatic index, and any of the relative fin lengths were not significantly different between the high and low densities. However, the hepatosomatic index was significantly greater in the fed fish compared to those fasted. The splenosomatic index was significantly greater in the higher density treatment. These results likely indicate no short-term stress response to the higher rearing density used in this short-term experiment and no interaction between starvation and density-related stressors.展开更多
清道夫受体B类成员1(scavenger receptor class B member 1,Scarb1)作为细胞表面的膜受体蛋白,在动物体色形成过程中发挥重要作用。为了解Scarb1基因在虹鳟(Oncorhynchus mykiss)体色形成中的作用,通过RACE技术克隆虹鳟Scarb1基因的cDN...清道夫受体B类成员1(scavenger receptor class B member 1,Scarb1)作为细胞表面的膜受体蛋白,在动物体色形成过程中发挥重要作用。为了解Scarb1基因在虹鳟(Oncorhynchus mykiss)体色形成中的作用,通过RACE技术克隆虹鳟Scarb1基因的cDNA全长,并运用生物信息学方法分析该基因及其序列结构特征,同时使用实时定量PCR(qRT-PCR)检测Scarb1基因在虹鳟、金鳟及其杂交F_(1)代不同发育阶段和不同组织中的表达情况。结果显示,Scarb1基因cDNA序列全长为2032 bp,开放阅读框1479 bp,编码492个氨基酸,预测分子质量为55.59 ku,且存在保守的CD36结构域和2个跨膜区。序列同源性分析显示,虹鳟与其他硬骨鱼类的氨基酸序列相似度为71.69%~98.58%;进化分析发现虹鳟与大马哈鱼亲缘关系最近,与哺乳动物和两栖动物亲缘关系最远。qRT-PCR检测结果表明,在虹鳟与金鳟胚胎期及出膜后各发育阶段中Scarb1基因均有不同程度表达,且表现为受精期至桑葚期的表达显著高于其他时期(P<0.05),对虹鳟与金鳟同一时期的差异分析发现该基因在胚胎期及7 dph(days post hatch)、1 M(month post hatch)、2 M和3 M时期中表达存在显著差异(P<0.01)。Scarb1基因在虹鳟与金鳟背部皮肤和背部肌肉等色素沉着性组织中表达量较高,其中在金鳟背部皮肤的表达量显著高于虹鳟(P<0.01)。此外,Scarb1基因在杂交F_(1)代不同发育时期中的表达规律与双亲一致;在不同组织中,该基因在杂交F_(1)代背部皮肤中的表达量介于双亲之间。研究结果表明,Scarb1基因与虹鳟体色形成有着密切关系,且可能在金鳟黄色体色形成过程中发挥重要作用。展开更多
基金funded by the CD40 (Departmental Council of the Landes)the “Universitéde Pau et Pays de l’Adour “(UPPA)
文摘Background High dietary carbohydrates can spare protein in rainbow trout(Oncorhynchus mykiss)but may affect growth and health.Inulin,a prebiotic,could have nutritional and metabolic effects,along with anti-inflammatory properties in teleosts,improving growth and welfare.We tested this hypothesis in rainbow trout by feeding them a 100%plant-based diet,which is a viable alternative to fishmeal and fish oil in aquaculture feeds.In a two-factor design,we examined the impact of inulin(2%)as well as the variation in the carbohydrates(CHO)/plant protein ratio on rainbow trout.We assessed the influence of these factors on zootechnical parameters,plasma metabolites,gut microbiota,production of short-chain fatty acids and lactic acid,as well as the expression of free-fatty acid receptor genes in the mid-intestine,intermediary liver metabolism,and immune markers in a 12-week feeding trial.Results The use of 2%inulin did not significantly change the fish intestinal microbiota,but interestingly,the high CHO/protein ratio group showed a change in intestinal microbiota and in particular the beta diversity,with 21 bacterial genera affected,including Ralstonia,Bacillus,and 11 lactic-acid producing bacteria.There were higher levels of butyric,and valeric acid in groups fed with high CHO/protein diet but not with inulin.The high CHO/protein group showed a decrease in the expression of pro-inflammatory cytokines(il1b,il8,and tnfa)in liver and a lower expression of the genes coding for tight-junction proteins in mid-intestine(tjp1a and tjp3).However,the 2%inulin did not modify the expression of plasma immune markers.Finally,inulin induced a negative effect on rainbow trout growth performance irrespective of the dietary carbohydrates.Conclusions With a 100%plant-based diet,inclusion of high levels of carbohydrates could be a promising way for fish nutrition in aquaculture through a protein sparing effect whereas the supplementation of 2%inulin does not appear to improve the use of CHO when combined with a 100%plant-based diet.
文摘Juvenile rainbow trout Oncorhynchus mykiss were subjected to one of four treatments in a two-by-two experimental design: 1) fed at a density of 1.8 g/m<sup>3</sup>, 2) Fasted at 1.8 g/m<sup>3</sup>, 3) fed at 30.1 g/m<sup>3</sup>, and 4) fasted at 30.1 g/m<sup>3</sup>. Blood glucose and hematocrit were measured at 4, 6, 48, 168, and 336 hours after placement in one of the two rearing densities, with relative fin lengths and organosomatic indices recorded at 336 hours. Glucose levels over time were not significantly different among the density and feeding treatments. Hematocrit levels over time were also not significantly different. Total lengths, weight, hepatosomatic index, viscerosomatic index, and any of the relative fin lengths were not significantly different between the high and low densities. However, the hepatosomatic index was significantly greater in the fed fish compared to those fasted. The splenosomatic index was significantly greater in the higher density treatment. These results likely indicate no short-term stress response to the higher rearing density used in this short-term experiment and no interaction between starvation and density-related stressors.
文摘清道夫受体B类成员1(scavenger receptor class B member 1,Scarb1)作为细胞表面的膜受体蛋白,在动物体色形成过程中发挥重要作用。为了解Scarb1基因在虹鳟(Oncorhynchus mykiss)体色形成中的作用,通过RACE技术克隆虹鳟Scarb1基因的cDNA全长,并运用生物信息学方法分析该基因及其序列结构特征,同时使用实时定量PCR(qRT-PCR)检测Scarb1基因在虹鳟、金鳟及其杂交F_(1)代不同发育阶段和不同组织中的表达情况。结果显示,Scarb1基因cDNA序列全长为2032 bp,开放阅读框1479 bp,编码492个氨基酸,预测分子质量为55.59 ku,且存在保守的CD36结构域和2个跨膜区。序列同源性分析显示,虹鳟与其他硬骨鱼类的氨基酸序列相似度为71.69%~98.58%;进化分析发现虹鳟与大马哈鱼亲缘关系最近,与哺乳动物和两栖动物亲缘关系最远。qRT-PCR检测结果表明,在虹鳟与金鳟胚胎期及出膜后各发育阶段中Scarb1基因均有不同程度表达,且表现为受精期至桑葚期的表达显著高于其他时期(P<0.05),对虹鳟与金鳟同一时期的差异分析发现该基因在胚胎期及7 dph(days post hatch)、1 M(month post hatch)、2 M和3 M时期中表达存在显著差异(P<0.01)。Scarb1基因在虹鳟与金鳟背部皮肤和背部肌肉等色素沉着性组织中表达量较高,其中在金鳟背部皮肤的表达量显著高于虹鳟(P<0.01)。此外,Scarb1基因在杂交F_(1)代不同发育时期中的表达规律与双亲一致;在不同组织中,该基因在杂交F_(1)代背部皮肤中的表达量介于双亲之间。研究结果表明,Scarb1基因与虹鳟体色形成有着密切关系,且可能在金鳟黄色体色形成过程中发挥重要作用。
