饲料蛋白水平对星斑川鲽幼鱼生长、体组成及血浆生化指标的影响

以鱼粉为蛋白源,配制5个不同蛋白质水平(34.85%,40.48%,46.54%,51.54%,56.69%)的等能饲料.以初始体质量为(54.52±0.23)g的星斑川鲽(Platichthys stellatus)为实验对象,在室内循环水养殖系统中进行54 d的摄食生长实验,研究饲料蛋白水平对星斑川鲽幼鱼生长、体组成及血浆生化指标的影响.结果显示:(1)增重率(WGR)和特定生长率(SGR)随着饲料蛋白水平的增加而上升,51.54%和56.69%饲料组之间差异不显著(P>0.05),其余各组差异显著(P<0.05);51.54%饲料组的蛋白质效率(PER)显著高于其他各组(P<0.05);51.54%饲料组的蛋白质沉积率(PRE)也显著高于34.85%、46.54%和56.69%组(P<0.05),但与40.48%饲料组差异不显著(P>0.05).以增重率为参考指标,折线回归分析结果表明,星斑川鲽幼鱼获得最佳增重时对饲料中蛋白质的需要量为53.56%.(2)饲料不同蛋白水平对星斑川鲽幼鱼鱼体灰分含量没有显著影响,但显著影响了鱼体粗蛋白、粗脂肪和水分的含量(P<0.05).51.54%饲料组鱼体粗蛋白含量最高,显著高于34.85%组(P<0.05),而与40.48%、46.54%和56.69%组之间无显著差异(P>0.05);鱼体粗脂肪含量随着饲料蛋白水平的升高而下降,水分含量表现出与粗脂肪含量相反的趋势.(3)饲料蛋白含量对星斑川鲽幼鱼部分血浆生化指标也产生了显著性的影响.血浆总蛋白(TP)以51.54%组最高,与56.69%组差异不显著(P>0.05),,但显著高于34.85%、40.48%和46.54%组(P<0.05);40.48%、51.54%和56.69%组间血浆尿素氮(BUN)含量差异不显著(P>0.05),但显著低于34.85%和46.54%组(P<0.05).综合以上结果,星斑川鲽饲料中蛋白质适宜添加量为51.54%～53.56%.

Effects of dietary protein level on growth performance, body composition and plasma biochemistry indices of juvenile starry flounder, Platichthys stellatus

A study was conducted to determine the effect of dietary protein level on growth performance, body composition and haematological parameters in juvenile starry flounder. Only fish meal was used as protein source to formulate five isoenergetic experimental diets at various protein levels were fed to triplicate groups of starry flounder (mean initial body weight: in a recirculating rearing system for 54 d. (1) Weight gain rate (WGR) and specific growth rate (SGR) were significantly improved with increasing dietary protein from 34.85% to 51.54% (<0.05) and leveled off.protein efficiency ratio (PER) of fish fed diet with 51.54% protein level was significantly higher than those of the other groups (<0.05). Protein retention efficiency (PRE) at 51.54% dietary protein was also significantly higher than those of the groups with 34.85%, 46.54% and 56.69% dietary proteins (<0.05), but there were no significant difference with 40.48% dietary protein (>0.05). analysis based on weight gain rate (WGR) indicated that dietary protein requirement for juvenile starry flounder was 53.65%. (2) Proximate composition of fish body was significantly affected by dietary lipid level. Body protein content significant difference <0.05) to 34.85% dietary protein group, while there were no significant differences with 40.48%, 46.54% and 56.69% groups (>0.05).Fat content in whole body decreased with the increase in dietary protein level. showed a reverse trend compared to Body ash content was not significantly affected by dietary protein level. (3) Plasma total protein (TP) concentration increased with increasing dietary protein level up to 51.54%, and then leveled off. Plasma urea nitrogen (UN) content at 51.54% dietary protein was significantly lower than those of 34.85% and 46.54% dietary proteins (<0.05), while there was no significant difference with 40.48% and 56.69% dietary proteins (>0.05). In considering these results, it was concluded that the optimum dietary protein requirement for