Krieg Jochen, Borda-Molina Daniel, Siegert Wolfgang, Sommerfeld Vera, Chi Yung Ping, Taheri Hamid Reza, Feuerstein Dieter, Camarinha-Silva Amélia, Rodehutscord Markus
Institute of Animal Science, University of Hohenheim, 70599, Stuttgart, Germany.
Department of Animal Science, Faculty of Agriculture, University of Zanjan, Zanjan, 45371-38791, Iran.
Anim Microbiome. 2021 Mar 15;3(1):23. doi: 10.1186/s42523-021-00083-7.
Diet acidification, dietary calcium (Ca) level, and phytase supplementation are known influences on the microbial community in the digestive tract and on phosphorus (P) utilization of broiler chickens. Effects of dietary factors and microbiota on P utilization may be linked because microorganisms produce enzymes that release P from phytate (InsP), the main source of P in plant feedstuffs. This study aimed to detect linkages between microbiota and InsP degradation by acidifying diets (i.e., replacing Ca carbonate (CaCO) by Ca formate or adding formic acid to CaCO-containing diets), varying Ca levels, and supplementing phytase in a three-factorial design. We investigated i) the microbial community and pH in the digestive tract, ii) prececal (pc) P and Ca digestibility, and iii) InsP degradation.
All factors under investigation influenced digesta pH and the microbiota composition. Predicted functionality and relative abundance of microorganisms indicated that diets influenced the potential contribution of the microbiota on InsP degradation. Values of InsP degradation and relative abundance of the strains Lactobacillus johnsonii and Lactobacillus reuteri were correlated. Phytase supplementation increased pc InsP disappearance, with differences between Ca levels, and influenced concentrations of lower inositol phosphate isomers in the digestive tract. Formic acid supplementation increased pc InsP degradation to myo-inositol. Replacing CaCO by Ca-formate and the high level of these Ca sources reduced pc InsP disappearance, except when the combination of CaCO + formic acid was used. Supplementing phytase to CaCO + formic acid led to the highest InsP disappearance (52%) in the crop and increased myo-inositol concentration in the ileum digesta. Supplementing phytase leveled the effect of high Ca content on pc InsP disappearance.
The results point towards a contribution of changing microbial community on InsP degradation in the crop and up to the terminal ileum. This is indicated by relationships between InsP degradation and relative abundance of phosphatase-producing strains. Functional predictions supported influences of microbiota on InsP degradation. The extent of such effects remains to be clarified. InsP degradation may also be influenced by variation of pH caused by dietary concentration and solubility of the Ca in the feed.
日粮酸化、日粮钙（Ca）水平和植酸酶添加已知会影响肉鸡消化道中的微生物群落以及磷（P）的利用率。日粮因素和微生物群对磷利用率的影响可能相互关联，因为微生物会产生从植酸盐（InsP）中释放磷的酶，而植酸盐是植物饲料中磷的主要来源。本研究旨在通过酸化日粮（即用甲酸钙替代碳酸钙（CaCO₃）或向含CaCO₃的日粮中添加甲酸）、改变钙水平以及采用三因素设计添加植酸酶来检测微生物群与InsP降解之间的联系。我们研究了：i）消化道中的微生物群落和pH值；ii）盲肠前段（pc）的磷和钙消化率；iii）InsP降解。
所有研究因素均影响消化物pH值和微生物群组成。对微生物功能的预测和相对丰度表明，日粮会影响微生物群对InsP降解的潜在贡献。InsP降解值与约氏乳杆菌和罗伊氏乳杆菌菌株的相对丰度相关。添加植酸酶增加了盲肠前段InsP的消失量，钙水平之间存在差异，并且影响了消化道中较低肌醇磷酸异构体的浓度。添加甲酸增加了盲肠前段InsP向肌醇的降解。用甲酸钙替代CaCO₃以及这些钙源的高剂量会降低盲肠前段InsP的消失量，但使用CaCO₃ + 甲酸组合时除外。向CaCO₃ + 甲酸中添加植酸酶导致嗉囊中InsP的消失量最高（52%），并增加了回肠消化物中肌醇的浓度。添加植酸酶可消除高钙含量对盲肠前段InsP消失量的影响。
结果表明，微生物群落的变化对嗉囊和直至回肠末端的InsP降解有贡献。这通过InsP降解与产磷酸酶菌株的相对丰度之间的关系得以体现。功能预测支持微生物群对InsP降解的影响。这种影响的程度仍有待阐明。InsP降解也可能受到日粮中钙的浓度和溶解度所引起的pH值变化的影响。
