饵料钙磷水平对七彩神仙鱼生长、体组成及消化酶活性的影响

Effects of dietary phosphorus and calcium levels on growth, body composition and digestive enzyme activities of juvenile discus fish(Symphysodon haraldi)

为探讨钙和磷对七彩神仙鱼生长、体组成及消化酶活性的影响,本研究设计了4个钙水平和3个磷水平,共配制12组饵料进行8周的养殖实验。结果表明,幼鱼存活率随饵料中磷水平的升高而显著降低。磷添加量为0. 5%或1. 0%时,体质量特定生长率随着钙水平的升高而显著下降。不添加钙时,磷的添加能显著提高体质量特定生长率,但添加量为1. 0%和0. 5%的组之间差异不显著。幼鱼体长特定生长率随着钙的添加显著降低,且钙、磷添加量分别为0%和1. 0%的组具有最大均值,同时该组体长/体高比值最小。饵料中钙、磷水平对全鱼水分、粗蛋白、粗脂肪和灰分含量均有显著影响。幼鱼肠道蛋白酶和脂肪酶的活力随着钙水平的升高而显著下降。钙和磷的单独添加对肠道淀粉酶无显著影响,但两者具有显著的交互作用。磷添加量为1. 0%时,淀粉酶活力随饵料钙水平的增加呈先升高后降低的趋势。钙和磷对肝脏谷丙转氨酶活力有显著交互作用。不添加磷时,肝脏谷丙转氨酶活力随着饵料中钙水平的升高而降低。以增重率、体重特定生长率和存活率综合考虑,七彩神仙鱼幼鱼饵料中钙和磷的适宜添加量分别为0%和0. 5%。

Twelve different diets with four calcium supply levels and three phosphorus supply levels were prepared for an 8-week feeding trial,which was conducted to investigate the effects of dietary calcium and phosphorus levels on growth,body composition and digestive enzyme activities of juvenile discus fish. The result at the end of the experimental showed that: the survival rate significantly reduced with the rise of dietary phosphorus supply. As 0. 5% or 1. 0% phosphorus supplied,the specific growth rate of weight( SGRW)sharply declined with the rise of dietary calcium level. Without calcium supplementation,the SGRW showed an obvious increase with phosphorus addition,but no significant difference was found between the two groups fed diets with 1. 0% and 0. 5% phosphorus supply. The specific growth rate of length( SGRL) significantly declined with the rise of dietary calcium supply. Fish fed diet with 1. 0% phosphorus and without calcium supplementation showed the highest SGRL value and lowest length/height ratio. Dietary calcium or phosphorus supply showed significant effect on moisture,crude protein,crude fat and ash content of whole fish. Both protease and lipase specific activities of intestinal tract significantly reduced with the rise of dietary calcium supplementation. Individual phosphorus or calcium supply did not affect the specific activity of amylase while an obvious interaction was found between calcium and phosphorus. In presence of 1. 0% phosphorus supplied in diets,amylase activity increased first with rising Ca level,followed by a reduction.Dietary calcium and phosphorus levels also showed an interaction on glutamic-pyruvic transaminase( GPT)activity,and individual calcium supplement showed a significant reduction on GPT activity without phosphorus supply. In summary,0. 5% phosphorus added without calcium was optimal for the growth of juvenile S.haraldi.