维生素A对养成期草鱼生长性能以及骨骼中钙磷含量变化的影响

EFFECTS OF DIETARY VITAMIN A ON GROWTH PERFORMANCE AND CALCIUM AND PHOSPHORUS CONTENTS IN BONE OF SUBADULT GRASS CARP (CTENOPHARYNGODON IDELLUS)

实验旨在探究养成期草鱼对饲料中维生素A的需求及维生素A对养成期草鱼的骨骼中钙磷含量的影响。选取养成期(254.6±0.5)g草鱼420尾,随机分为7组,每组3个重复,每个重复20尾。分别用维生素A含量为89、732、1129、2378、4688、7218和9802 IU/kg的等氮等能实验饲料喂养84d。实验结果表明:(1)饲料中添加4688 IU/kg的维生素A显著提高了养成期草鱼的特定生长率(P<0.05),并显著降低了饲料系数(P<0.05),但饲料维生素A含量对鱼体摄食率、成活率以及肝脏指数没有显著影响(P>0.05)。(2)饲料添加维生素A对鱼体粗蛋白、粗脂肪、灰分没有显著影响(P>0.05),但是9802 IU/kg组的鱼体水分显著低于其他实验组(P<0.05)。(3)饲料中4688 IU/kg的维生素A显著提高血清中超氧化物歧化酶的活性(P<0.05),但饲料维生素A水平对血清丙二醛、钙、磷含量以及碱性磷酸酶活性没有显著影响(P>0.05)。(4)饲料添加4688和7218 IU/kg的维生素A能显著提高草鱼头骨和脊椎骨中灰分以及钙、磷含量(P<0.05)。在实验条件下,以特定生长率、饲料系数以及血清SOD活性为评价指标,通过折线分析得出养成期草鱼适宜维生素A的需求量分别为3184和3077 IU/kg。

To determine the optimum dietary requirement of vitamin A （VA） of subadult grass carp （Ctenopharyn-godon idellus）, seven isoenergetic and isonitrogenous semi-purified diets were formulated to contain VA level at 89, 732, 1129, 2378, 4688, 7218 and 9802 IU/kg diet respectively, for a 12-week growth trial that was conducted in 21 net-cages located in an earth pond. The results indicated that dietary VA level significantly regulated the specific growth rate （SGR） and feed conversion ratio （FCR） of subadult grass carp （P〈0.05） with the highest SGR and the lowest FCR both in 4688 IU/kg group. Feeding rate, survival rate and hepatosomatic index were not affected by dietary VA level （P＆gt;0.05）. Dietary VA level showed significant （P〈0.05） effect on serum SOD activity with the highest SOD values in 4688 IU/kg group. Serum ALP activity, MDA, calcium （Ca） and phosphorus （P） contents were not significantly （P〉0.05） affected by dietary VA level. Body moisture content in 9802 IU/kg group was significantly lower. Body lipid, protein and ash contents were not affected by dietary VA level （P〉0.05）. The ash contents either in skull or in vertebra were significantly affected （P〈0.05） by dietary VA level. The higher Ca and P contents in skull and vertebra were both observed in 4688 and 7218 IU/kg groups （P〈0.05）. Broken-line analysis for the SGR of fish suggested that the optimal dietary VA content for subadult grass carp was 3184 IU/kg diet.