Mo Jianxin, Li Guoling, Huang Guangyan, Wang Haoqiang, Shi Junsong, Zhou Rong, Cai Gengyuan, Wu Zhenfang, Zhang Xianwei
National Engineering Research Center for Breeding Swine Industry, Wens Foodstuff Group Co., Ltd., Yunfu, China.
College of Animal Science, South China Agricultural University, Guangzhou, China.
Front Genet. 2021 Mar 4;12:631071. doi: 10.3389/fgene.2021.631071. eCollection 2021.
We previously generated transgenic pigs with enhanced growth rate and reduced nutrient loss. However, the composition of their gut microbiome is unknown. In this study, we successfully generated marker-free transgenic (MF-TG) pigs with high expression levels of microbial β-glucanase, xylanase, and phytase in the parotid gland. We collected intestinal contents from the ileum, cecum and colon of five MF-TG and five wild-type (WT) sows and investigated the gut microbiome of the transgenic pigs via metagenomic analysis. Results showed that the levels of probiotics, such as and , were more abundant in the cecum of the MF-TG pigs and higher than those of WT pigs. By contrast, the levels of harmful microorganisms, such as , , and , and various unidentified viruses, were higher in the cecum of the WT pigs than those of the MF-TG pigs. By comparing unigenes and the eggNOG database, we found that the microorganisms in the colon of the MF-TG pigs had high fractional abundance in DNA (cytosine-5)-methyltransferase 1 and serine-type D-Ala-D-Ala carboxypeptidase, whereas the aspartate carbamoyltransferase regulatory subunit and outer membrane protein pathways were enriched in the WT pigs. Moreover, the microorganisms in the cecum of the MF-TG pigs were active in GlycosylTransferase Family 8 (GT8), Glycoside Hydrolase Family 13 (GH13), and Glycoside Hydrolase Family 32 (GH32). Furthermore, the levels of numerous carbohydrases, such as glucan 1,3-beta-glucosidase, xylan 1,4-beta-xylosidase and exo-1,3-1,4-glucanase, were higher in the cecum of the MF-TG pigs than those of the WT pigs. The results indicated that intestinal microbes can change adaptively to the secretion of transgenic enzymes, thereby forming a benign cooperation with their host. This cooperation could be beneficial for improving feed efficiency.
我们之前培育出了生长速度加快且营养损失减少的转基因猪。然而，它们肠道微生物群的组成尚不清楚。在本研究中，我们成功培育出了在腮腺中高表达微生物β-葡聚糖酶、木聚糖酶和植酸酶的无标记转基因（MF-TG）猪。我们从5头MF-TG母猪和5头野生型（WT）母猪的回肠、盲肠和结肠中收集了肠道内容物，并通过宏基因组分析研究了转基因猪的肠道微生物群。结果显示，MF-TG猪盲肠中的益生菌（如[具体益生菌名称1]和[具体益生菌名称2]）水平更为丰富，且高于WT猪。相比之下，WT猪盲肠中的有害微生物（如[具体有害微生物名称1]、[具体有害微生物名称2]和[具体有害微生物名称3]）以及各种未鉴定病毒的水平高于MF-TG猪。通过将单基因与eggNOG数据库进行比较，我们发现MF-TG猪结肠中的微生物在DNA（胞嘧啶-5）-甲基转移酶1和丝氨酸型D-丙氨酰-D-丙氨酸羧肽酶方面具有较高的相对丰度，而天冬氨酸氨甲酰基转移酶调节亚基和外膜蛋白途径在WT猪中富集。此外，MF-TG猪盲肠中的微生物在糖基转移酶家族8（GT8）、糖苷水解酶家族13（GH13）和糖苷水解酶家族32（GH32）中具有活性。此外，MF-TG猪盲肠中许多碳水化合物酶（如葡聚糖1,3-β-葡萄糖苷酶、木聚糖1,4-β-木糖苷酶和外切-1,3-1,4-葡聚糖酶）的水平高于WT猪。结果表明，肠道微生物可以对转基因酶的分泌进行适应性改变，从而与宿主形成良性合作。这种合作可能有利于提高饲料效率。
