饲料中不同泛酸水平对凡纳滨对虾生长性能、饲料利用及血清指标的影响

为研究饲料中不同泛酸水平对凡纳滨对虾生长性能、饲料利用及血清指标的影响,实验配制6种等氮等脂(41%粗蛋白质和8%粗脂肪)的实验饲料,泛酸添加水平分别为0(对照组)、50、100、150、300和600 mg/kg,饲料中实测泛酸水平分别为20.9、69.3、99.0、150.2、304.4和513.6 mg/kg。选用初始体质量为(0.73±0.12)g的凡纳滨对虾720尾,随机分为6组(每组3个重复,每个重复40尾),进行为期8周的养殖实验。结果显示,饲料中不同泛酸水平对凡纳滨对虾增重率和特定生长率的影响不显著;对照组凡纳滨对虾成活率显著低于泛酸添加组,然而各泛酸添加组的成活率组间差异不显著。随着泛酸水平从20.9 m.g/kg增加到99.0 mg/kg时,饲料效率和蛋白质效率显著提高,而随着泛酸水平的进一步增加,饲料效率和蛋白质效率显著降低。饲料中泛酸水平对凡纳滨对虾全虾和肌肉主要成分无显著性影响。对照组对虾血清葡萄糖含量显著低于泛酸各添加组,然而泛酸各添加组之间无显著差异;投喂150.2 mg/kg泛酸组血清甘油三酯含量显著低于对照组和513.6 mg/kg;而血清总蛋白和胆固醇含量不受饲料中泛酸水平的影响。随着饲料中泛酸水平由20.9 mg/kg增至150.2 mg/kg,血清超氧化物歧化酶活力显著提高,而随着饲料中泛酸水平的进一步增加,血清超氧化物歧化酶活力显著降低;饲料中泛酸水平为99.0mg/kg组凡纳滨对虾血清总氧化能力显著高于其他各组;投喂对照组和泛酸水平为69.3mg/kg组的凡纳滨对虾血清丙二醛含量最高,投喂泛酸水平为150.2 mg/kg组血清的丙二醛含量显著低于其他各组。以凡纳滨对虾的饲料效率和蛋白质沉积率为评价指标,通过折线模型分析得到凡纳滨对虾泛酸最适需要量分别为113.40和119.87mg/kg。

Effects of different dietary pantothenic acid levels on growth performance, feed utilization and serum indices of juvenile Litopenaeus vannamei

An 8-week feeding trial was conducted to evaluate the effects of different dietary pantothenic acid levels on growth performance, feed utilization and serum indices of juvenile Pacific white shrimp (Litopenaeus vannamei). Six isonitrogenous and isolipidic practical diets (41% crude protein and 8% crude lipid) were formulated to supplement with pantothenic acid levels were of (control diet), 50, 100, 150, 300 and 600 mg/kg, respectively. The analyzed values of dietary pantothenic acid are 20.9, 69.3, 99.0, 150.2, 304.4 and 513.6 mg/kg, respectively. Each diet was randomly assigned to 3 replicates of 40 juvenile shrimps (initial weight approximately 0.73±0.12 g). The results indicated that weight gain rate and specific growth rate were not significantly affected by dietary pantothenic acid levels (P>0.05). However, shrimp fed the control diet had lower survival rate than those fed the diets supplemented with pantothenic acid (P<0.05), while there were no significant differences among those supplemented with pantothenic acid. Feed efficiency and protein efficiency rate significantly increased with dietary pantothenic acid level increasing from 20.9 mg/kg to 99.0 mg/kg, then decreased with further increase of dietary pantothenic acid level from 150.2 mg/kg to 513.6 mg/kg. Composition of whole body and muscle in the juvenile L. vannamei were not significantly influenced by the dietary pantothenic acid levels (P>0.05). Shrimp fed control pantothenic acid diet had lower glucose concentration in serum than those fed the other diets, while there were no significant differences among all diets supplemented with pantothenic acid. Shrimp fed the diet containing 150.2 mg/kg pantothenic acid had lower TG in serum than those fed the diets containing 20.9 mg/kg and 513.6 mg/kg. Total protein and cholesterol in serum were not affected by dietary pantothenic acid levels. SOD activity in serum increased significantly with dietary pantothenic acid level increasing from 20.9 mg/kg to 150.2 mg/kg, then decreased significantly with further increase of dietary pantothenic acid level (P<0.05). Shrimp fed the diet containing 99.0 mg/kg pantothenic acid had higher T-AOC than the other diets. Shrimp fed the diet containing 69.3 mg/kg pantothenic acid and control diet had higher level MDA in serum than those fed the other diets, and the lowest MDA in serum occurred at diet containing 150.2 mg/kg pantothenic acid (P<0.05). Based on a two-slope broken-line model between feed efficiency, productive protein value and dietary pantothenic acid levels, the optimal dietary pantothenic acid requirement is estimated to be 113.40 and 119.87 mg/kg for juvenile Pacific white shrimp, respectively.