黄河鲇幼鱼对饲料中钙、磷的需要量

为探明黄河鲇Silurus lanzhouensis幼鱼对饲料钙、磷的适宜需要量,选取总能、钙、粗蛋白质、非植酸磷、赖氨酸5个因素作为试验因素,每个因素各设6个水平,钙为0.50%~1.34%,非植酸磷为0.50%~1.00%,采用均匀设计法U*6(64)设计6种配合饲料,饲喂体质量为(170±5)g的黄河鲇幼鱼,分别记为A、B、C、D、E、F组,饲养时间为60 d。试验结束后,以增重率、特定生长率、肌肉和肝脏RNA/DNA值、粗蛋白质离体消化率为试验指标,采用偏最小二乘法建立回归方程,通过降维分析和优化求解,分析研究黄河鲇幼鱼对饲料中钙和非植酸磷的适宜需要量。结果表明:C组(钙0.56%、非植酸磷0.60%)试验鱼的增重率、特定生长率和肌肉RNA/DNA最高,分别为84.83%、1.02%和2.98,肠、肝、胃中粗蛋白质离体消化率也达到最大值,分别为67.53%、66.76%、51.52%;随着饲料中钙、非植酸磷含量的增加,鱼体增重率、特定生长率、肌肉RNA/DNA值和粗蛋白质离体消化率均呈现先上升后下降的趋势。研究表明,饲料中钙和非植酸磷含量对黄河鲇幼鱼生长、蛋白质合成能力、饲料粗蛋白质离体消化率影响明显,黄河鲇幼鱼对饲料中钙的适宜需要量为0.54%,对非植酸磷的适宜需要量为0.50%~0.53%。

Requirements of juvenile catfish Silurus lanzhouensi for dietary calcium and non-phytate phosphorus

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 rati-o 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 phos-phorus 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.