Abstract This study was carried out to investigate the effects of reduced dietary calcium (Ca) and non-phytate-phosphorus (NPP) levels on performance, carcase yield and bone mineralisation of modern broilers. 11,200 one-day-old chicks (Ross-308) were divided into 7 treatments and 8 replicates with standard recommended level and six different levels of Ca and NPP reduction with completely randomised block design. Treatments were divided into following diets; T1: ross recommended control, T2: 94%, 95% and 91% as percentage of T1, T3: 94%, 95% and 83% as percentage of T1, T4: 94%, 91% and 83% as percentage of T1, T5: 94%, 91% and 77% as percentage of T1, T6: 94%, 86% and 83% as percentage of T1 and T7: 94%, 86% and 77% as percentage of T1 for starter, grower and finisher periods, respectively. Results showed that, the Ca and NPP reduction (T2–T7) through starter period did not significantly (p>.05) affect performance but when considered whole period, quadratically (p<.05) improved body weight gain (BWG), feed conversion ratio (FCR) and European Production Efficiency (EPEF). In line with, Ca and NPP intakes were decrease linearly and quadratically with Ca and NPP reducing in diet and higher intakes at T1 resulted in impaired BWG and FCR. On the other hand, carcase parameters and tibia mineralisation were not significantly affected by the reductions. In conclusion, Ca and NPP requirements of Ross 308 broilers seem to be lower than the Aviagen 2014 and 2019 recommendations and reducing almost 20% Ca and NPP intake of broilers is possible, especially after starter period, to maintain performance without any negative effect on bone development. Highlights Excessive dietary Ca and P feeding have potential deleterious effects on broilers. Dietary Ca and NPP reduction improved growth performance, without impairment bone characteristics. Especially after starter period, Ca and NPP reduction, by keeping the dietary levels as 0.90:0.45, 0.75;0.38 and 0.60;0.30% for starter, grower and finisher phase respectively, seems enough for Ross-308.

中文翻译：

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现代肉鸡对低于推荐值的膳食钙和磷水平的反应

摘要 本研究旨在研究降低日粮钙 (Ca) 和非植酸磷 (NPP) 水平对现代肉鸡生产性能、胴体产量和骨矿化的影响。11200只一日龄雏鸡（Ross-308）分为7个处理8个重复，标准推荐水平和6个不同水平的Ca和NPP降低，完全随机区组设计。治疗分为以下饮食：T1：罗斯推荐对照，T2：T1 的 94%、95% 和 91%，T3：T1 的 94%、95% 和 83%，T4：T1 的 94%、91% 和 83% , T5: 94%、91% 和 77% 作为 T1 的百分比, T6: 94%、86% 和 83% 作为 T1 和 T7 的百分比: 94%、86% 和 77% 作为 T1 的百分比，用于起始者、种植者和完赛期，分别。结果表明，Ca 和 NPP 的降低（T2-T7）在整个孕育期没有显着影响（p>.05），但考虑到整个时期，体重增加（BWG）、饲料转化率（FCR）成二次方（p<.05） ) 和欧洲生产效率 (EPEF)。与此一致，Ca 和 NPP 的摄入量随着饮食中 Ca 和 NPP 的减少呈线性和二次下降，并且在 T1 时摄入量增加导致 BWG 和 FCR 受损。另一方面，胴体参数和胫骨矿化没有受到减少的显着影响。总而言之，Ross 308 肉鸡的 Ca 和 NPP 要求似乎低于 Aviagen 2014 和 2019 年的建议，并且可以减少近 20% 的肉鸡 Ca 和 NPP 摄入量，尤其是在开产期之后，以保持性能而不对骨骼产生任何负面影响发展。亮点 日粮中过量的钙和磷饲喂对肉鸡有潜在的有害影响。膳食钙和 NPP 的减少改善了生长性能，而不会损害骨骼特征。特别是在育苗期之后，通过将育苗期、生长期和育肥期的日粮水平分别保持为 0.90:0.45、0.75;0.38 和 0.60;0.30%，对 Ross-308 来说，Ca 和 NPP 的降低似乎就足够了。