Influence of dairy by-product waste milk on the microbiomes of different gastrointestinal tract components in pre-weaned dairy calves

Y F Deng,Z J Cao,D F Shao,Y Zou,Z H Wu,J Zhang,S L Li,A Azarfar,J X Xiao,Y Xu,S K Ji,S Z Dong,X L Wei,S X Wang,K L Yang,Y J Wang

doi:10.1038/srep42689

Abstract

The community structure of colonised bacteria in the gastrointestinal tracts (GITs) of pre-weaned calves is affected by extrinsic factors, such as the genetics and diet of the calves; however, the dietary impact is not fully understood and warrants further research. Our study revealed that a total of 6, 5, 2 and 10 bacterial genera showed biologically significant differences in the GITs of pre-weaned calves fed four waste-milk diets: acidified waste milk, pasteurised waste milk, untreated bulk milk, and untreated waste milk, respectively. Specifically, generic biomarkers were observed in the rumen (e.g., Bifidobacterium, Parabacteroides, Fibrobacter, Clostridium, etc.), caecum (e.g., Faecalibacterium, Oxalobacter, Odoribacter, etc.) and colon (e.g., Megamonas, Comamonas, Stenotrophomonas, etc.) but not in the faeces. In addition, the predicted metabolic pathways showed that the expression of genes related to metabolic diseases was increased in the calves fed untreated waste milk, which indicated that untreated waste milk is not a suitable liquid diet for pre-weaned calves. This is the first study to demonstrate how different types of waste milk fed to pre-weaned calves affect the community structure of colonised bacteria, and the results may provide insights for the intentional adjustment of diets and gastrointestinal bacterial communities.

Highlights

pasteurised waste milk (PWM) UBM pathogens[8,9,10]
Significant differences in bacterial richness and diversity were indicated among the dietary groups (Table 1), suggesting that the diet had a prominent effect on the microbial community composition of pre-weaned dairy calves
The current results demonstrated that the microbial community structures occupying the gastrointestinal tract (GIT) of the pre-weaned dairy cattle were influenced by the four types of milk

Summary

Introduction

Feeding pasteurised waste milk to calves has been reported to result in better performance, health, and additional economic profit compared with feeding untreated waste milk[11]. Acidification is another popular method of processing waste milk, which reduces calf exposure to pathogenic bacteria in waste milk. Regardless of the applied technological processing method, an additional concern with feeding waste milk to calves is the presence of residues from antimicrobial agents, which may increase the risk of antibiotic resistance in the gastrointestinal microflora[14] and inhibit the establishment of microbial communities pertinent to the gastrointestinal tract (GIT) of neonate calves. The current study aimed to assess the effects of feeding dairy calves waste milk (no treatment or subjected to pasteurisation or acidification) on the digesta and mucosa-associated bacteria throughout the GIT using the Illumina HiSeq (NEB, USA) sequencing technique

Methods

Results

Conclusion