饲粮钙、磷缺乏对1～21日龄肉仔鸡生长性能、佝偻病发病特征及胫骨组织结构的影响

Effects of Dietary Calcium and Phosphorus Deficiency on Growth Performance,Rickets Incidence Characters and Tibia Histological Structure of Broilers during 1 to 21 Days of Age

本试验旨在研究饲粮钙、磷缺乏对1～21日龄肉仔鸡生长性能、佝偻病发病特征及胫骨组织结构的影响。试验选用504只1日龄爱拔益加肉公雏,采用2×2两因子完全随机试验设计,设2个钙水平(1.00%和0.35%)与2个非植酸磷水平(0.45%和0.23%),分为4个组,分别为正常对照组(1.00%钙+0.45%非植酸磷)、磷缺乏组(1.00%钙+0.23%非植酸磷)、钙缺乏组(0.35%钙+0.45%非植酸磷)和钙磷同时缺乏组(0.35%钙+0.23%非植酸磷),每组7个重复,每个重复18只鸡。试验期为21 d。结果表明:钙与磷的交互作用对1～21日龄肉仔鸡各个阶段的平均日采食量、平均日增重、料重比,7、14和21日龄胫骨长度,7日龄胫骨生长板增生区和肥大区长度以及14日龄胫骨生长板肥大区长度均具有显著影响(P<0.05)。在正常钙水平时,低磷显著降低了1～21日龄肉仔鸡各个阶段的平均日采食量和平均日增重(P<0.05),显著增加了料重比(P<0.05),显著提高了7和14日龄胫骨生长板肥大区长度(P<0.05);在低钙水平时,低磷显著提高了15～21日龄和1～21日龄平均日增重以及7日龄胫骨生长板肥大区长度(P<0.05),显著降低了7日龄胫骨生长板增生区长度(P<0.05)。此外,与磷缺乏组相比,钙缺乏组和钙磷同时缺乏组1～21日龄肉仔鸡各个阶段的平均日采食量、平均日增重以及7日龄胫骨生长板增生区长度显著提高(P<0.05),7和14日龄胫骨生长板肥大区长度显著降低(P<0.05)。由此可见,肉仔鸡生长性能和胫骨结构对磷缺乏最为敏感,其次为钙缺乏,钙磷同时缺乏的影响较弱;三者佝偻病的典型特征分别为磷缺乏组的胫骨生长板肥大区长度增长,钙缺乏组和钙磷同时缺乏组的胫骨生长板增生区长度均增长,但钙磷同时缺乏组早期胫骨生长板增生区长度小于钙缺乏组。

This experiment was conducted to investigate the effects of dietary calcium(Ca)or phosphorus(P)deficiency on growth performance,rickets incidence characters and tibia histological structure of broilers during 1 to 21 days of age.A total of 504 one-day-old Arbor Acres male broilers were selected,and a 2×2 two-factor complete random test design was adopted,there were two Ca levels(1.00%and 0.35%)and two non-phytate phosphorus(NPP)levels(0.45%and 0.23%),the 4 groups were normal control group(1.00%Ca+0.45%NPP),P deficiency group(1.00%Ca+0.23%NPP),Ca deficiency group(0.35%Ca+0.45%NPP)and Ca and P deficiency group(0.35%Ca+0.23%NPP),respectively;and there were 7 replicates per groups and 18 broilers per replicate.The experiment lasted for 21 days.The results showed that the interaction between Ca and P levels was significantly affected the average daily feed intake,average daily gain and feed to gain ratio at all stage of broilers during 1 to 21 days of age,tibia length at 7,14 and 21 days of age,the lengths of proliferating zone and hypertrophy zone in tibia growth plate at 7 days of age,and the length of hypertrophy zone in tibia growth plate at 14 days of age(P<0.05).In the normal Ca level,low P significantly decreased the average daily feed intake and average daily gain at all stage of broilers during 1 to 21 days of age(P<0.05),significantly increased the feed to gain ratio(P<0.05),and significantly improved the length of hypertrophy zone in tibia growth plate at 7 and 14 days of age(P<0.05);in the low Ca level,low P significantly improved the average daily gain during 15 to 21 days of age and 1 to 21 days of age and the length of hypertrophy zone in tibia growth plate at 7 days of age(P<0.05),and significantly decreased the length of proliferating zone in tibia growth plate at 7 days of age(P<0.05).Besides,compared with the P deficiency group,the average daily feed intake and average daily gain at all stage of broilers during 1 to 21 days of age and the length of proliferating zone in tibia growth plate at 7 days of age of Ca deficiency group and Ca and P deficiency group were significantly increased(P<0.05),and the length of hypertrophy zone in tibia growth plate at 7 and 14 days of age was significantly decreased(P<0.05).The results indicate that the growth performance and tibia structure are the most sensitive to the P deficiency,followed by the Ca deficiency,and then the Ca and P deficiency has weaker influence.The typical characteristics of rickets show that the length of hypertrophy zone in tibia growth plate is lengthened in the P deficiency group,while the length of proliferating zone in tibia growth plate is lengthened in the Ca deficiency group and Ca and P deficiency group,but Ca and P deficiency group has the shorter length of proliferating zone in tibia growth plate than Ca deficiency group in the early stage.