Künzel Susanne, Borda-Molina Daniel, Kraft Rebecca, Sommerfeld Vera, Kühn Imke, Camarinha-Silva Amélia, Rodehutscord Markus
Institut für Nutztierwissenschaften, Universität Hohenheim, 70599, Stuttgart, Germany.
AB Vista, 64293, Darmstadt, Germany.
Anim Microbiome. 2019 Jun 28;1(1):5. doi: 10.1186/s42523-019-0006-2.
There is good evidence for a substantial endogenous phytase activity originating from the epithelial tissue or the microbiota resident in the digestive tract of broiler chickens. However, ionophore coccidiostats, which are frequently used as feed additives in broiler diets to prevent coccidiosis, might affect the bacterial composition and the abundance of phytase producers in the gastrointestinal tract. The aim of the present study was to investigate whether supplementation of a frequently used mixture of the coccidiostats Narasin and Nicarbazin alone or together with a phytase affects microbiota composition of the digestive tract of broiler chickens, characteristics of phytate breakdown in crop and terminal ileum, and precaecal phosphorus and crude protein digestibility.
Large differences in the microbial composition and diversity were detected between the treatments with and without coccidiostat supplementation. Disappearance of myo-inositol 1,2,3,4,5,6-hexakis(dihydrogen phosphate) (InsP) in the digestive tract, precaecal P digestibility, inorganic P in blood serum, and the concentration of inositol phosphate isomers in the crop and ileum digesta were significantly affected by phytase supplementation, but not by coccidiostat supplementation. Crude protein digestibility was increased by coccidiostat supplementation when more phosphate was available. Neither microbial abundance and diversity nor any other trait measured at the end of the experiment was affected by coccidiostat when it was only supplemented from day 1 to 10 of age.
The coccidiostats used herein had large effects on overall microbiota composition of the digestive tract. The coccidiostats did not seem to affect endogenous or exogenous phytase activity up to the terminal ileum of broiler chickens. The effects of phytase on growth, phosphorus digestibility, and myo-inositol release were not altered by the presence of the coccidiostats. The effects of phytase and coccidiostats on nutrient digestibility can be of significant relevance for phosphorus and protein-reduced feeding concepts if confirmed in further experiments.
有充分证据表明，肉仔鸡消化道中的上皮组织或微生物群可产生大量内源性植酸酶活性。然而，常用于肉仔鸡日粮以预防球虫病的离子载体抗球虫药，可能会影响胃肠道细菌组成和植酸酶产生菌的丰度。本研究的目的是探究单独添加常用的抗球虫药那拉菌素和尼卡巴嗪混合物，或与植酸酶一起添加，是否会影响肉仔鸡消化道的微生物群组成、嗉囊和回肠末端植酸盐分解特性以及盲肠前磷和粗蛋白消化率。
在添加和未添加抗球虫药的处理之间，检测到微生物组成和多样性存在很大差异。植酸酶添加显著影响消化道中肌醇1,2,3,4,5,6 - 六磷酸（InsP）的消失、盲肠前磷消化率、血清无机磷以及嗉囊和回肠食糜中肌醇磷酸异构体的浓度，但抗球虫药添加未产生显著影响。当有更多磷酸盐可用时，添加抗球虫药可提高粗蛋白消化率。仅在1至10日龄添加抗球虫药时，实验结束时的微生物丰度和多样性以及所测的任何其他性状均未受到影响。
本文所用的抗球虫药对消化道的整体微生物群组成有很大影响。抗球虫药似乎不会影响肉仔鸡回肠末端的内源性或外源性植酸酶活性。抗球虫药的存在并未改变植酸酶对生长、磷消化率和肌醇释放的影响。如果在进一步实验中得到证实，植酸酶和抗球虫药对养分消化率的影响对于低磷和低蛋白日粮概念可能具有重要意义。
