Rubio Luis A
Department of Animal Nutrition and Sustainable Production, Estación Experimental del Zaidín, 18008 Granada, Spain.
Poult Sci. 2024 Dec;103(12):104365. doi: 10.1016/j.psj.2024.104365. Epub 2024 Sep 27.
Growing broiler chickens of the Cobb500 strain were used to determine the effects on intestinal microbiota composition of a protein-free (PF) diet as compared to a diet based in casein (CAS) as the only protein source. CAS was formulated to contain the same amount of protein (190 g kg) as a commercial Maize-soy diet which was used as a practical reference. The ileal AA flow (g kg dry matter intake) was significantly higher (P < 0.001) than PF in birds fed protein containing diets (CAS or Maize-soy). Taken as a whole (discriminant and ANOSIM analysis), the intestinal (ileal and caecal contents and ileal tissue) microbiota composition of PF and CAS were significantly (P < 0.001) different from Maize-soy and not different from each other in some cases. RT-qPCR and sequencing analysis of the ileal and caecal microbiota revealed significant (P < 0.05) differences in a number of bacterial groups between broilers fed PF, CAS or Maize-soy diets. The main result was that the lack of protein in the intestinal medium of PF birds resulted in a drop of Lactobacillus spp. counts (on average, 43 in PF vs 1,734 in the Maize-soy diet) and increased Enterobacteriaceae (on average, 419 in PF vs 172 in the Maize-soy diet) and other potentially pathogenic bacterial groups (in both intestinal contents and tissue). Thus, the lack of protein in the intestinal medium of PF birds resulted in a microbiota composition compatible with a pro-inflammatory state, and this effect was somewhat less marked in birds fed CAS. The results reported here suggest that the adverse effects on microbiota composition in broilers fed CAS were less marked than in those fed PF, which would be in line with a preferential use of a highly digestible protein containing diet to determine endogenous AA excretion instead of a PF diet.
选用科宝500品系的生长肉鸡，以确定与以酪蛋白（CAS）作为唯一蛋白质来源的日粮相比，无蛋白（PF）日粮对肠道微生物群组成的影响。CAS日粮的蛋白质含量（190 g/kg）与用作实际对照的商业玉米-豆粕日粮相同。在采食含蛋白质日粮（CAS或玉米-豆粕日粮）的鸡中，回肠氨基酸流量（g/kg干物质摄入量）显著高于PF日粮组（P<0.001）。总体而言（判别分析和ANOSIM分析），PF日粮组和CAS日粮组的肠道（回肠和盲肠内容物以及回肠组织）微生物群组成与玉米-豆粕日粮组存在显著差异（P<0.001），在某些情况下，PF日粮组和CAS日粮组之间无差异。对回肠和盲肠微生物群的RT-qPCR和测序分析显示，采食PF、CAS或玉米-豆粕日粮的肉鸡在多个细菌类群上存在显著差异（P<0.05）。主要结果是，PF日粮组鸡的肠道培养基中缺乏蛋白质导致乳酸杆菌属数量下降（平均而言，PF日粮组为43，玉米-豆粕日粮组为1734），肠杆菌科数量增加（平均而言，PF日粮组为419，玉米-豆粕日粮组为172）以及其他潜在致病细菌类群数量增加（在肠道内容物和组织中均如此）。因此，PF日粮组鸡的肠道培养基中缺乏蛋白质导致微生物群组成与促炎状态相符，而在采食CAS日粮的鸡中这种影响不太明显。此处报告的结果表明，采食CAS日粮对肉鸡微生物群组成的不利影响不如采食PF日粮的肉鸡明显，这与优先使用高消化率的含蛋白质日粮来确定内源性氨基酸排泄量而非PF日粮的情况相符。
