本试验旨在研究磷酸一二钙(MDCP)和磷酸氢钙(DCP)对福美双诱导的肉鸡胫骨软骨发育不良(TD)及骨骼钙、磷代谢的影响。选取1日龄科宝(Cobb)肉雏鸡120只,试验1~21 d采用2因子设计,按磷源的不同分为2个处理(磷源DCP和MDCP),每个处理60只鸡;试验22~42 d采用2×2因子设计,将每种磷源按福美双的添加水平不同再分为2个处理(福美双水平为0和100 mg/kg),每个处理3个重复,每个重复10只鸡。福美双组在基础饲粮中添加100 mg/kg福美双,于22~28 d饲喂,然后换喂对应不含福美双饲粮。结果表明:1)MDCP组肉鸡第35天TD评分相对DCP组有降低的趋势(P=0.09),但磷源对肉鸡第28和42天TD评分影响差异不显著(P>0.05)。福美双显著升高了肉鸡第28、35和42天TD评分(P<0.05)。2)福美双和磷源对肉鸡第35天胫骨灰分、钙和磷含量交互效应显著(P<0.05)。福美双诱导条件下,MDCP组肉鸡第35天胫骨灰分、钙、磷含量显著高于DCP组(P<0.05)。3)DCP组第35天血清甲状旁腺素含量高于MDCP组(P=0.12)。由此可见,相对DCP,MDCP对福美双诱导的TD发生有一定减缓作用,且与肉鸡骨骼钙、磷代谢密切相关。2种磷源对肉鸡最终TD评分影响差异不显著。

This trial was conducted to investigate the effects of mono-dicalcium phosphate (MDCP) and dicalciumphosphate (DCP) on thiram-induced tibia dyschondroplasia (TD) and bone calcium-phosphorus metabolism in broilers. A total of 120 Cobb broilers at 1 day of age were randomly assigned to 2 dietary treatments according to phosphorous sources (DCP and MDCP) at 1 to 21 d, and each treatment had 60 broilers. At 22 to 42 d, the experimental design consisted of a 2?2 factorial arrangement for 4 treatments. The broilers fed diets with DCP or MDCP at 1 to 21 d were divided into two treatments at 22 d and they were fed diets with two levels of thiram (0, 100 mg/kg). Each treatment was three replicates with ten broilers in each replicate. While the thiram diet was fed only at 22 to 28 d and then they were switched to normal diets without thiram. The results showed as follows: 1) TD scores of broilers from MDCP group were lower than those of broilers from DCP group at 35 d (P=0.09), however, it showed no significant difference for TD scores at 28 and 42 d between the two phosphorus sources (P>0.05). Thiram significantly increased TD scores of broilers at 28, 35 and 42 d (P<0.05). 2) The interactions were significant for tibia ash, Ca and P contents at 35 d (P<0.05). Tibia ash, Ca, and P contents of broilers from MDCP group were significantly higher than those of broilers from DCP group under thiram-induced condition at 35 d. 3) Serum parathyroid hormone (PTH) content of broilers from DCP group was higher than that of broilers from DCP group at 35 d (P=0.12). MDCP may slow down the development of thiram-induced TD compared with DCP, which is related to calcium-phosphorus metabolism. It shows no significant influence on final TD scores between the two phosphorus sources.