An evaluation of phytase for Channel catfish (Ictalurus punctatus) fed all plant-protein diet: Growth performance, nutrient utilization and P equivalency value

作者：Chen, Aijing; Liu, Xingbiao; Cui, Cunhe; Yang, Chenghui; Wang, Yuyu; Bu, Xianyong; Yang, Yuhong^*

来源：Aquaculture Nutrition, 2019, 25(1): 215-224.

DOI：10.1111/anu.12845

• apparent digestibility coefficient
• channel catfish (Ictalurus punctatus)
• growth performance
• nutrient excretion
• phytase

This study evaluated the effect and phosphorus equivalency value of dietary microbial phytase based on growth performance and nutrient utilization of Channel catfish (Ictalurus punctatus). An all plant-protein basal diet containing 7.9 g/kg total Phosphorus (P) (Phytate P of 4.5 g/kg) was supplemented with graded levels 0, 300, 500, 1,000, 1,500 and 2,000 U phytase/kg of diet or with 3, 5, 8, 12 g/kg of Ca(H2PO4)(2), namely with 0.7, 1.2, 2.0, 3.09 g/kg P as Ca(H2PO4)(2). Triplicate groups of Channel catfish (Ictalurus punctatus) juveniles (initial weight, 1.70 +/- 0.04 g) were fed the experiment diets for 90 days. The results indicated that dietary phytase supplementation significantly improved growth performance, apparent digestibility coefficient of P and P retention, and decreased feed conversion ratio (FCR), faecal P content and P excretion per gain. Line relation was found between the effects of P and phytase supplementation levels, and the linear response equations of the effects of P and phytase levels were generated and used to calculate the P equivalency values. The average function of P equivalency values (Y, g/kg) of microbial phytase (X, U/kg of diet) was developed: Y = 0.1695 + 0.0021X; R-2 = 0.996. The results showed that about 0.38 g of P/kg diet was released by per 100 U of phytase over the range of 300-2,000 U of phytase/kg diet for Channel catfish (Ictalurus punctatus) fed all plant-protein diet.

• 出版日期2019-2
• 单位东北农业大学