Requirements of juvenile catfish Silurus lanzhouensi for dietary calcium and non-phytate phosphorus
WANG Yan1,SAI Qing-yun2,ZHAO Rui-zhi1,ZHAO Hong-xue1,WU Xu-dong2,QIU Xiao-zong1
1.School of Life Science,Ningxia University,Yinchuan 750021,China;2.Fisheries Research Institute of Ningxia Hui Autonomous Region,Yinchuan 750001,China
Abstract: The juvenile catfish Silurus lanzhouensis with body weight of(170±5)g were fed six formulated diets containing calcium from 0.50%to 1.34%,non-phytate phosphorus from 0.50%to 1.00%and six levels of gross energy,crude protein,and lysine with uniform design U*6(64)for 60 days to estimate the requirements of juvenile catfish for calcium and non-phytate phosphorus.The results showed that the maximum growth performance and ratio of RNA/DNA,and the maximum weight gain(84.83%),specific growth rate(1.02%),and ratio of RNA/ DNA(2.98)in muscle were observed in the fish fed the third diet containing 0.56%of calcuium,and 0.60%of non-phytate phosphorus.There were maximal in vitro apparent crude protein digestibility in intestine(67.53%), liver(66.76%)and stomach(51.52%),and weight gain,specific growth rate,and the ratio of RNA/DNA in muscle were increased with increase in the content of dietary calcium and non-phytate phosphorus at the early stage and then decreased in the late stage.The findings indicated that growth performance,protein synthesis capacity, and the crude protein in vitro digestibility were significantly influenced by dietary calcium and non-phytate phosphorus levels.It is recommended that the optimal dosage of calcium in diets be 0.54%,and that of non-phytate phosphorus ranged from 0.50%to 0.53%for juvenile catfish.
2017, Vol. 32 
