饲料有效磷水平对黄鳝幼鳝生长性能、形体指标、体成分及血清生化指标的影响

Effects of Dietary Available Phosphorus Levels on Growth Performance,Body Composition and Serum Biochemical Indexes of Juvenile Rice Field Eel,Monopterus albus

【目的】旨在确定黄鳝生长发育磷(P)的需求量,为降低磷排放提供参考依据。【方法】以磷酸二氢钙[Ca(H2PO4)2]为磷源,制备有效磷(AP)水平分别为0.65%、0.83%、1.00%、1.25%、1.46%、1.69%和1.86%的7组等氮等能饲料,用其饲养黄鳝[体质量(3.17±0.002)g/尾]10周,试验结束后取样,测定其生长性能、形体指标、体成分及血清生化指标。【结果】随着饲料AP水平升高,黄鳝8周的增重率(WGR)、特定生长率(SGR)先升高后下降,在饲料AP水平为1.23%时达到最佳,而黄鳝10周的WGR、SGR先保持稳定后下降,在饲料AP水平为1.22%时达到最佳。当饲料AP水平超过1.69%时,黄鳝的摄食率,肥满度、胴体比显著减小(P<0.05)。饲料AP水平对黄鳝全鱼水分、粗蛋白、粗脂肪、肝脏粗脂肪均无显著影响(P>0.05)。随着饲料AP水平升高,黄鳝全鱼磷呈先保持平稳后显著升高的趋势(P<0.05);肝糖原呈先升高后下降的趋势,在1.46%组达最高值(P<0.05);脊椎骨灰分呈先升后降趋势,在1.25%组最高,在0.65%组最低(P<0.05);脊椎骨总磷呈先升高后保持平稳的趋势,1.25%组最高,但各组间无显著差异(P>0.05);黄鳝的磷沉积率呈下降趋势(P<0.05),但各组的磷沉积量无显著差异(P>0.05)且均趋近1 mg/d。当饲料AP水平超过1.25%,血清磷显著下降(P<0.05)。随着饲料AP水平的升高,血清碱性磷酸酶(AKP)活性、总抗氧化能力(T-AOC)显著下降(P<0.05),而血清谷草转氨酶(GOT)活性显著升高(P<0.05)。【结论】以增重率为评价指标,黄鳝幼鳝(3~15 g)的磷需求量为1.23%,以脊椎骨总磷、脊椎骨灰分为评价指标黄鳝幼鳝(3~24 g)骨骼矿化对饲料的磷需求量为1.24%~1.36%。

[Objective]This study aims to determine the phosphorus demand for the growth and development of rice field eel and provide reference for reducing phosphorus emission.[Method]Using monocalcium phosphate as phosphorus source,seven groups of isonitrogenous and isoenergetic feeds with available phosphorus(AP)contents of 0.65%,0.83%,1.00%,1.25%,1.46%,1.69% and 1.86% were prepared to feed rice field eel(initial body weight,(3.17±0.002)g)for 10 weeks.After the test,samples were taken to determine growth performance,body indicators,body composition and serum biochemical indicators.[Result]With the increase of dietary AP level,the weight gain rate(WGR)and specific growth(SGR)of rice field eel increased first and then decreased in 8 weeks,reaching the optimal growth performance when the AP level in diet was 1.23%,while the WGR and SGR of rice field eel remained stable first and then decreased in 10 weeks,reaching the best optimal growth performance when the AP level in diet was 1.22%.When the dietary AP level exceeded1.69%,the feed rate,condition factor and carcass ratio of rice field eel decreased significantly(P0.05).With the increase of dietary AP level,the total phosphorus of rice field eel showed a trend of remaining stable at first and then increasing significantly(P0.05).With the increase of dietary AP level,the phosphorus retention of rice field eel decreased significantly(P0.05),they all approached 1 mg/(g·ind).When the dietary AP level exceeded1.25%,the serum phosphorus decreased significantly(P<0.05).With the increase of dietary AP level,the serum alkaline phosphatase(AKP)activity and total antioxidant capacity(T-AOC)decreased significantly(P<0.05),but the activity of serum glutamic oxaloacetic transaminase(GOT)increased significantly(P<0.05).[Conclusion]Adopting the WGR as the evaluation index,the demand of phosphorus for the suitable growth of juvenile rice field eels(3-15 g)is 1.23%.Adopting the vertebrae phosphorus and vertebrae ash as evaluation indexes,the demand of bone mineralization of juvenile rice field eels(3-24 g)for phosphorus in diet is 1.24%-1.36%.