A Short-Term Feeding of Dietary Casein Increases Abundance of Lactococcus lactis and Upregulates Gene Expression Involving Obesity Prevention in Cecum of Young Rats Compared With Dietary Chicken Protein.

Fan Zhao,Chunbao Li,Xinglian Xu,Yafang Ma,Guanghong Zhou,Shangxin Song

doi:10.3389/fmicb.2019.02411

Fan Zhao, Chunbao Li + Show 4 more

Open Access

https://doi.org/10.3389/fmicb.2019.02411

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Abstract

Casein and chicken are assessed to contain high quality proteins, which are essential for human health. Studies have shown that ingestion of the two dietary proteins resulted in distinct effects on physiology, liver transcriptome and gut microbiota. However, its underlying mechanism is not fully understood, in particular for a crosstalk between gut microbiota and host under a specific diet intervention. We fed young rats with a casein or a chicken protein-based diet (CHPD) for 7 days, and characterized cecal microbiota composition and cecal gene expression. We found that a short-term intervention with a casein-based diet (CAD) induced a higher relative abundance of beneficial bacterium Lactococcus lactis as well as Bifidobacterium pseudolongum, which upregulated galactose metabolism of the microbiome compared with a CHPD. The CAD also upregulated gene expression involved in obesity associated pathways (e.g., Adipoq and Irs1) in cecal tissue of rats. These genes and the bacterial taxon were reported to play an important role in protecting development of obesity. Furthermore, the differentially represented bacterial taxon L. lactis was positively associated with these differentially expressed genes in the gut tissue. Our results provide a new insight into the crosstalk between gut microbiota and host in response to dietary proteins, indicating a potential mechanism of obesity prevention function by casein.

Highlights

Meat and dairy products are the major dietary animal protein sources for human nutrition, which contain high quantities and balanced proportions of amino acids relative to human tissues (Li et al, 2011; FAO, 2013)
We found that a shortterm intervention with a casein-based diet (CAD) induced a higher relative abundance of beneficial bacterium Lactococcus lactis as well as Bifidobacterium pseudolongum, which upregulated galactose metabolism of the microbiome compared with a chicken protein-based diet (CHPD)
Great differences were observed in gut microbiota composition in cecum of rats fed with CAD and CHPD

Summary

Introduction

Meat and dairy products are the major dietary animal protein sources for human nutrition, which contain high quantities and balanced proportions of amino acids relative to human tissues (Li et al, 2011; FAO, 2013). Chicken consumption has grown by 70% in developed countries since 1990 and it becomes one of the most widely consumed meat, indicating its increasing effects on human health. A number of studies have shown that there is a close association among obesity, high fat diet and gut microbiota (Martinez et al, 2017). Several long-term animal studies have shown that casein or CHPDs varied in their effects on obesity development in high fat diet fed mice (Liisberg et al, 2016) and gut microbiota in normal fat diet fed rats (Zhu et al, 2015), indicating a crucial impact of the protein sources. Dietary protein-associated changes in the gut microbiota could be causally linked with host metabolism. Most of the associated analyses on gut microbiota were conducted based on 16s rRNA sequencing, which may cause a bias

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