Effects of early feeding on the host rumen transcriptome and bacterial diversity in lambs.

Weimin Wang,Ting Liu,Xiangpeng Yue,Futao Mo,Yongfu La,Fadi Li,Fangbin Wang,Xiaojuan Wang,Chong Li,Fang Nian,Baosheng Li,Fei Li,Xiaoxue Zhang,Xiangyu Pan

doi:10.1038/srep32479

Weimin Wang, Ting Liu + Show 12 more

Open Access

https://doi.org/10.1038/srep32479

Copy DOI

Abstract

Early consumption of starter feed promotes rumen development in lambs. We examined rumen development in lambs fed starter feed for 5 weeks using histological and biochemical analyses and by performing high-throughput sequencing in rumen tissues. Additionally, rumen contents of starter feed-fed lambs were compared to those of breast milk-fed controls. Our physiological and biochemical findings revealed that early starter consumption facilitated rumen development, changed the pattern of ruminal fermentation, and increased the amylase and carboxymethylcellulase activities of rumen micro-organisms. RNA-seq analysis revealed 225 differentially expressed genes between the rumens of breast milk- and starter feed-fed lambs. These DEGs were involved in many metabolic pathways, particularly lipid and carbohydrate metabolism, and included HMGCL and HMGCS2. Sequencing analysis of 16S rRNA genes revealed that ruminal bacterial communities were more diverse in breast milk-than in starter feed-fed lambs, and each group had a distinct microbiota. We conclude that early starter feeding is beneficial to rumen development and physiological function in lambs. The underlying mechanism may involve the stimulation of ruminal ketogenesis and butanoate metabolism via HMGCL and HMGCS2 combined with changes in the fermentation type induced by ruminal microbiota. Overall, this study provides insights into the molecular mechanisms of rumen development in sheep.

Highlights

Consumption of starter feed promotes rumen development in lambs
The weight of the reticulo-rumen (WRR), the volume of the reticulo-rumen (VRR), and the papilla height (PH) of the rumen were higher in the starter feed-fed group than in the breast milk-fed group
We found that genes associated with the carbohydrate and lipid metabolism pathways were all up-regulated in starter feed-fed lambs, including HMGCL, HMGCS2, PCK2, and MCEE suggesting that rumen carbohydrate and lipid metabolism were more active in starter feed-fed lambs than in breast milk-fed lambs

Summary

Introduction

Consumption of starter feed promotes rumen development in lambs. We examined rumen development in lambs fed starter feed for 5 weeks using histological and biochemical analyses and by performing high-throughput sequencing in rumen tissues. RNA-seq analysis revealed 225 differentially expressed genes between the rumens of breast milk- and starter feed-fed lambs. These DEGs were involved in many metabolic pathways, lipid and carbohydrate metabolism, and included HMGCL and HMGCS2. Administering grain-based feed and orchard grass hay to neonatal ruminants significantly increase the length and density of the rumen papillae, whereas feeding milk alone resulted in little development of these structures and poor animal growth[10]. This feeding strategy provides biologically appropriate fuels, and is thought to enhance early rumen development. The application of such an approach would allow for much greater coverage of the microbial diversity and physiology of a complex environment, such as the rumen in calves[26], cows[27,28], and goats[29]

Methods

Results

Discussion

Conclusion