Apparent digestibility of nutrents in grass carp(Ctenopharyngodon idellus)diet supplemented with graded levels of neutral phytase using pretreatment and spraying methods
The effects of supplemental graded levels of neutral phytase using pretreatment and spraying methods on the apparent digestibility coefficients (ADCs) of protein, minerals and amino acids were investigated in grass carp (Ctenopharyngodon idellus) (mean weight, 20.92±1.04g).Seven experimental diets were prepared as: no-phytase supplementation (control), pretreatment with phytase dose of 500 U (PP500), 1000 U (PP1000) and 1500 U (PP1500) per kg diet.With spraying method, the phytase was added to feed at the same three grades, namely 500 U (PS500), 1000 U (PS1000) and 1500 U (PS1500) per kg diet.After an 8-week feeding trial,addition of phytase improved the crude protein, crude lipid, dry matter, ash, phosphorus and calcium digestibilities in comparison with the control, especially in the diets where phytase addition level was above 1000 U kg-1 (P<0.05).Phytase supplementation, both the pretreatment and sprayng, significantly enhanced the ADCs of essential amino acid (EAA) and non-essential amino acid.The ADCs of the nutrients were significantly influenced by phytase supplementation methods, supplementation levels and interaction of methods and levels.Based on the results, supplemental dietary phytase, regardless of application methodology, improved the ADCs of nutrients in grass carp, and the pretreatment mode ofphytase application was more effective than spraying at the same phytase level.We suggest that the optimal level of phytase pretreatment is 1000 U kg-1 diet, and the best addition level of phytase spraying is 1500 U kg-1 diet or more phytase is required for spraying.
Ctenopharyngodon idellus neutral phytase nutrient digestibility pretreatment,spraying
L.W.LIU J.M.SU T.ZHANG X.-F.LIANG Y.L.LUO
College of Fisheries,Huazhong Agricultural University,Wuhan,China College of Life Science and Technology,Huazhong Agricultural University,Wuhan,China
国内会议
武汉
英文
109-116
2013-03-28（万方平台首次上网日期，不代表论文的发表时间）