Chen Jiashun, Kang Baoju, Jiang Qian, Han Mengmeng, Zhao Yurong, Long Lina, Fu Chenxing, Yao Kang
College of Animal Science and Technology, Hunan Agricultural University, Changsha, China.
Key Laboratory of Agro-Ecological Processes in Subtropical Region, Hunan Provincial Engineering Research Center of Healthy Livestock, Scientific Observing and Experimental Station of Animal Nutrition and Feed Science in South-Central, Ministry of Agriculture, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, China.
Front Microbiol. 2018 May 31;9:1057. doi: 10.3389/fmicb.2018.01057. eCollection 2018.
Alpha-ketoglutarate (AKG), a critical molecule in the tricarboxylic acid cycle, is beneficial to intestinal functions. However, its influence on intestinal microbiota and metabolism is not fully understood. We investigated the effects of a low-protein (LP) diet supplemented with AKG on cecal microbial communities and the parameters of microbial metabolism in growing pigs. Twenty-seven young pigs (Large White × Landrace) with an average initial body weight of 11.96 ± 0.18 kg were randomly allotted into three groups ( = 9): a normal protein (NP) diet containing 20% crude protein (CP); LP diet formulated with 17% CP (LP diet); or LP diet supplemented with 10 g kg of AKG (ALP diet). After a 35-day trial period, the digesta of the cecum were collected to analyze the concentrations of ammonia and short-chain fatty acids (SCFAs). We also performed a microbial analysis. Although no significant differences were found in performance among the diet groups, pigs fed the ALP diet had greater average daily gain (ADG) when compared with those in the LP group. Experimental diet did not affect cecal bacterial richness or diversity, as determined by Chao1 and ACE species richness measures and Shannon and Simpson indices, respectively. The predominant phyla Firmicutes, Bacteroidetes, and Proteobacteria increased in relative abundances in the cecum of pigs fed ALP diet. At the genus level, compared to the LP diet, the ALP diet significantly increased the abundances of UCG-005, NK4A136 group, and , while decreased and . Pigs fed the ALP diet increased and when compared with the NP diet. Non-metric multidimensional scaling analysis revealed that the distribution of microbiota at each group was distinctly clustered separately along principal coordinate. In addition, quantitative PCR revealed that the ALP diet was also associated with increases in the amounts of , and , but a decrease in the level of . Compared with the NP diet, the ALP diet enhanced the concentrations of valerate and propionate. This ALP diet also increased the concentrations of valerate and isobutyrate when compared with the LP diet. Moreover, the ALP diet was linked with a significant decline in the concentration of ammonia in the cecum. These results indicate that a LP diet supplemented with AKG can alter the balance in microbial communities, increasing the population of SCFA-producing bacteria and the amounts of and , while reducing the counts of and the amount of ammonia in the cecum.
α-酮戊二酸（AKG）是三羧酸循环中的关键分子，对肠道功能有益。然而，其对肠道微生物群和代谢的影响尚未完全明确。我们研究了添加AKG的低蛋白（LP）日粮对生长猪盲肠微生物群落及微生物代谢参数的影响。将27头平均初始体重为11.96±0.18 kg的大白×长白仔猪随机分为三组（每组9头）：含20%粗蛋白（CP）的正常蛋白（NP）日粮；含17% CP的LP日粮（LP日粮）；或添加10 g/kg AKG的LP日粮（ALP日粮）。经过35天的试验期后，收集盲肠内容物以分析氨和短链脂肪酸（SCFA）的浓度。我们还进行了微生物分析。虽然日粮组之间在生长性能上未发现显著差异，但与LP组相比，采食ALP日粮的猪平均日增重（ADG）更高。分别通过Chao1和ACE物种丰富度测量以及香农和辛普森指数确定，试验日粮对盲肠细菌丰富度或多样性没有影响。在采食ALP日粮的猪的盲肠中，优势菌门厚壁菌门、拟杆菌门和变形菌门的相对丰度增加。在属水平上，与LP日粮相比，ALP日粮显著增加了UCG-005、NK4A136组和的丰度，同时降低了和的丰度。与NP日粮相比，采食ALP日粮的猪增加了和。非度量多维标度分析显示，每组微生物群的分布沿主坐标明显分开聚类。此外，定量PCR显示，ALP日粮还与、和数量的增加有关，但水平降低。与NP日粮相比，ALP日粮提高了戊酸和丙酸的浓度。与LP日粮相比，这种ALP日粮还增加了戊酸和异丁酸的浓度。此外，ALP日粮与盲肠中氨浓度的显著下降有关。这些结果表明，添加AKG的LP日粮可以改变微生物群落平衡，增加产生SCFA的细菌数量以及和的数量，同时减少盲肠中和氨的数量。
