体外法探究不同氨基酸形式酪蛋白水解物对猪小肠微生物的影响

Effect of two different casein hydrolysates on small intestinal bacteria of growing pigs

摘要:

[目的]通过体外法探究猪小肠不同肠段肠腔微生物和肠壁微生物对两种不同氨基酸形式的酪蛋白水解物的发酵特性。[方法]以生长猪的十二指肠、空肠、回肠肠腔食糜或者肠壁微生物为接种物，分别以酸水解酪蛋白（以游离氨基酸为主）和酶水解酪蛋白（以小肽为主）为底物，37℃厌氧培养发酵，于0、3、6、12 h采样，测定微生物蛋白（MCP）以及用real time-PCR进行菌群分析。[结果]（1）肠腔微生物发酵不同酪蛋白水解物：十二指肠和回肠酶水解酪蛋白组MCP的含量显著高于酸水解酪蛋白组（P<0.05）。十二指肠酶水解酪蛋白组总菌、Firmicutes数量显著高于酸水解酪蛋白组（P<0.05）。回肠发酵6 h后，酶水解酪蛋白组Escherichia coli和Firmicutes的数量显著高于酸水解酪蛋白组（P<0.05）；发酵12 h后，酶水解酪蛋白组总菌、Lactobacillus、E.coli的数量均显著高于酸水解酪蛋白组（P<0.05）。（2）肠壁微生物发酵不同酪蛋白水解物：发酵12 h后，十二指肠和回肠酶水解酪蛋白组MCP含量显著高于酸水解酪蛋白组（P<0.05）。十二指肠酶水解酪蛋白组Lactobacillus、Firmicutes数量分别极显著、显著高于酸水解酪蛋白组；回肠Firmicutes数量在酶水解酪蛋白组显著高于酸水解酪蛋白组（P<0.05）。[结论]十二指肠和回肠的肠腔和肠壁微生物都能够利用小肽，且在一定程度上对小肽的利用更具优势。

Abstract:

[Objective] This study was aimed to explore the effect of different casein hydrolysates on small intestinal bacteria of pigs.[Methods] Luminal and gut wall bacteria from duodenum, jejunum and ileum in Duroc, Landrace and Yorkshire hybridization pigs were used as inocula. Casein acid hydrolysate and casein enzymatic hydrolysate were fermented at 37℃ for 12 h. Samples were collected at 0, 3, 6 and 12 h to measure microbial protein and detect the alteration of bacteria community.[Results] After inoculated with the luminal bacteria, the concentration of microbial protein in duodenum and ileum in casein enzymatic hydrolysate group was higher compared with casein acid hydrolysate group and the casein enzymatic hydrolysate group had higher total bacteria number and Firmicutes in duodenum after 12 h incubation (P<0.05). In the casein enzymatic hydrolysate group, the numbers of total bacteria, Lactobacillus and Escherichia coli were higher than those in casein acid hydrolysate group after 12 h incubation in ileum. For the gut wall bacteria:in duodenum and ileum, after 12 h incubation, the concentration of microbial protein in the casein enzymatic hydrolysate group was higher than that in casein acid hydrolysate group (P<0.05). The number of Lactobacillus and Firmicutes in the casein enzymatic hydrolysate group was higher than those in the casein acid hydrolysate group in duodenum (P<0.05) and the number of Firmicutes was higher in the casein enzymatic hydrolysate group than that in the casein acid hydrolysate group in ileum. (P<0.05).[Conclusion] Compared with casein acid hydrolysate, casein enzymatic hydrolysate can promote the bacterial protein synthesis and stimulate the growth of Firmicutes in duodenum and ileum.