Institute of Animal Science, University of Hohenheim, Stuttgart 70599, Germany.
Department of Poultry Science, University of Georgia, Athens, GA 30602, USA.
Poult Sci. 2023 Dec;102(12):103160. doi: 10.1016/j.psj.2023.103160. Epub 2023 Oct 2.
This study aimed to determine the effect of Zn source and dietary level on intestinal myo-inositol hexakisphosphate (InsP) disappearance, intestinal accumulation of lower InsP and myo-inositol (MI), prececal mineral digestibility, bone mineralization, and Zn status of broilers without and with exogenous phytase in the feed. Male Ross 308 broilers were allocated in groups of 10 to 8 treatments with 8 pens each. Experimental diets were fed from d 7 to d 28 and contained 33 mg/kg dry matter plant-intrinsic Zn. Experimental factors were phytase supplementation (0 or 750 FTU/kg) and Zn source (none [0 mg/kg Zn], Zn-sulfate [30 mg/kg Zn], Zn-oxide [30 mg/kg Zn]). Additional treatments with 90 mg/kg Zn as Zn-sulfate or Zn-oxide and phytase were included to test the effect of Zn level. No Zn source or Zn level effects were observed for ADG, feed conversion ratio, prececal P digestibility, intestinal InsP disappearance, and bone ash concentration. However, those measurements were increased by exogenous phytase (P < 0.001), except the feed conversion ratio, which was decreased (P < 0.001). Ileal MI concentrations were affected by phytase × Zn source interaction (P < 0.030). Birds receiving exogenous phytase and Zn supplementation had the highest MI concentrations regardless of exogenous Zn source, whereas MI concentrations were intermediate for birds receiving exogenous phytase only. Exogenous phytase and exogenous Zn source increased the Zn concentration in bone and blood of broilers (P < 0.001). In conclusion, measures of exogenous phytase efficacy were not affected by phytase × Zn source interaction. Further studies are needed to rule out an effect from Zn sources other than those tested in this study and to investigate the effect of Zn supplementation on endogenous phosphatases. The missing effect of increasing Zn supplementation from 30 to 90 mg/kg in phytase-supplemented diets gives reason to reconsider the Zn supplementation level used by the industry.
本研究旨在确定锌源和饲粮水平对肉鸡肠道肌醇六磷酸（InsP）消失率、肠道低级 InsP 和肌醇（MI）蓄积、回肠矿物质消化率、骨矿化和饲粮添加或不添加植酸酶时肉鸡锌状况的影响。将雄性罗斯 308 肉鸡按 10 只分为一组，共 8 组，每组 8 个重复。试验饲粮从第 7 天至第 28 天饲喂，饲粮中植物源内源锌含量为 33mg/kg 干物质。试验因素为植酸酶添加（0 或 750 FTU/kg）和锌源（无 [0mg/kg 锌]、硫酸锌 [30mg/kg 锌]、氧化锌 [30mg/kg 锌]）。此外，还设置了添加 90mg/kg 锌的硫酸锌或氧化锌和植酸酶的处理，以检验锌水平的影响。ADG、饲料转化率、回肠磷消化率、肠道 InsP 消失率和骨灰浓度不受锌源或锌水平的影响。然而，外源性植酸酶（P<0.001）可提高这些指标，除了饲料转化率（P<0.001）降低。植酸酶与锌源互作对回肠 MI 浓度有影响（P<0.030）。添加外源性植酸酶和锌补充的鸡无论外源性锌源如何，MI 浓度均最高，而仅添加外源性植酸酶的鸡 MI 浓度居中。外源性植酸酶和外源性锌源增加了肉鸡骨骼和血液中的锌浓度（P<0.001）。综上所述，外源性植酸酶效果的衡量指标不受植酸酶与锌源互作的影响。需要进一步的研究来排除本研究中未测试的锌源以外的其他锌源的影响，并研究锌补充对内源性磷酸酶的影响。在添加植酸酶的饲粮中，将锌补充量从 30mg/kg 增加到 90mg/kg 并未产生效果，这使得人们有理由重新考虑行业使用的锌补充量。
