三种温度下不同饲料方案对大菱鲆幼鱼生长和氧化应激的影响

Effects of Different Diet Strategies on Growth Performance and Oxidative Stressing of Juvenile Turbot at Three Temperatures

温度会对鱼类的营养需求产生影响,为研究不同温度条件下不同饲料方案对大菱鲆(Scophthalmus maximus L.)幼鱼生长和氧化应激的影响,确定不同温度下最适合的饲料方案。设计了等脂等能的4种实验饲料,分别为45%蛋白15%糊精的低蛋白组(LP组)、50%蛋白10%糊精的对照组(CON组)、55%蛋白0%糊精的高蛋白组(HP组)和50%蛋白20%糊精的高糖组(HC组)。在3个温度条件下(15、18和21℃)挑选初始质量(7.50±0.10) g的幼鱼进行8周的养殖实验,并对生长、抗氧化应激指标和抗氧化指标应激相关基因表达情况进行研究。研究显示,15℃时,CON组和LP组的特定生长率(SGR)显著高于HP组(P<0.05),且CON组和LP组肝脏丙二醛(MDA)含量显著低于HP组和HC组(P<0.05)。18℃时,CON组的SGR最高,显著高于LP组(P<0.05);且CON组肝脏MDA含量最低(P<0.05)。21℃时,HP组有最高的SGR和最低的饲料系数(FC)(P<0.05),且HP组肝脏MDA含量显著低于LP组和HC组(P<0.05)。在本实验3种温度条件下HC组肝脏MDA含量都最高;同时,CON组和HP组可通过上调Nrf2-ARE信号通路中相关基因来提高鱼体抗氧化能力。研究结果表明,在低温度下适合投喂低中蛋白饲料,在适温度条件下适合投喂中蛋白饲料,在高温度条件下适合投喂高蛋白饲料,高糖饲料会导致严重的氧化应激。

Temperature affects the nutrient requirement of fish.In order to study the optimal diet for juvenile turbot(Scophthalmus maximus L.)under different temperature conditions and the effects of different diet strategies on the growth and oxidative stress of turbot,four experimental diets with isolipid and isoergy were designed and compared.The compared included the low protein group(LP group)with 45%protein and 15%dextrin,control group(CON group)with 50%protein and 10%dextrin,high protein group(HP group)with 50%protein and 10%dextrin and high sugar group(HC group)with 50%protein and 20%dextrin.At three temperatures(15,18 and 21℃),juvenile fish with an initial mass of(7.50±0.10)g were selected and cultured for 8 weeks.The results showed that the specific growth rate(SGR)of the CON group and the LP group was significantly higher than that of HP group(P<0.05)at 15℃,and the liver malondialdehyde(MDA)content of the CON group and the LP group was significantly lower than that of HP group and HC group(P<0.05).The CON group had the highest SGR,significantly higher than of LP group(P<0.05)at 18℃,and the CON group had the lowest MDA content in the liver(P<0.05).The HP group had the highest SGR and the lowest feed coefficient(FC)(P<0.05)at 21℃,and the liver MDA content was significantly lower than that of the LP and HC groups(P<0.05).In addition,the liver MDA content of the HC group was the highest at three temperatures,and the CON group and the HP group improved the antioxidant capacity of fish by up-regulating the expression of genes functioning in Nrf2-ARE signaling pathway.Our findings demonstrated that low and medium protein diets are suitable for feeding at low temperatures;medium protein diets are suitable for feeding at moderate temperatures;high protein diets are suitable for feeding at high temperatures;and high sugar diets cause severe oxidative stressing.