The effects of differential feeding on ileum development, digestive ability and health status of newborn calves

Abstract

Pre-weaning is the most important period for the growth and development of calves. Intestinal morphology, microbial community and immunity are initially constructed at this stage, and even have a lifelong impact on calves. Early feeding patterns have a significant impact on gastrointestinal development and microbial communities. This study mainly analyzed the effects of three feeding methods on the gastrointestinal development of calves, and provided a theoretical basis for further improving the feeding mode of calves. it is very important to develop a suitable feeding mode. In this study, we selected nine newborn healthy Holstein bull calves were randomly selected and divided into three groups (n = 3), which were fed with starter + hay + milk (SH group), starter + milk (SF group), total mixed ration + milk (TMR group). After 80 days of feeding Feeding to 80 days of age after, the ileum contents and blood samples were collected, and the differences were compared and analyzed by metagenomic analysis and serum metabolomics analysis. Results show that compared with the other two groups, the intestinal epithelium of the SH group was more complete and the goblet cells developed better. The feeding method of SH group was more conducive to the development of calves, with higher daily gain and no pathological inflammatory reaction. The intestinal microbial community was more conducive to digestion and absorption, and the immunity was stronger. These findings are helpful for us to explore better calf feeding patterns. In the next step, we will set up more biological replicates to study the deep-seated reasons for the differences in the development of pre-weaning calves. At the same time, the new discoveries of neuro microbiology broaden our horizons and are the focus of our future attention.

Keywords: calves; feeding patterns; metabolomics; metagenomics; neuro microbiology.

Figure 1

Hematoxylin and eosin (100×) -stained ileal tissue samples of Holstein calves fed different diets. (A) SH group; (B) SF group; (C) TMR group. Red circle marked mucosal epithelial shedding; the orange circle marked congestion; green circle marked as parasitic lesions.

Figure 2

Some physiological indexes test results. (A–D) It’s blood routine determination results. (E–H) It’s digestive enzyme and immunoassay results.

Figure 3

Correlation analysis between groups of samples.

Figure 4

Analysis of microbial community differences between groups. (A) Relative abundance of species at phylum level TOP10. (B) Relative abundance of genus level species TOP10. (C) Phylum level species PCA analysis. (D) PCA analysis of genus-level species.

Figure 5

LDA score of LEfSe-PICRUSt. (A) LDA score analysis diagram of different species between SH group and TMR group. (B) LDA score analysis diagram of different species between SF group and TMR group.

Figure 6

KEGG pathway enrichment analysis. (A) KEGG level 2 enrichment analysis top 10 between groups. (B) KEGG level 3 enrichment analysis top 10 between groups.

Figure 7

EggNOG enrichment analysis.

Figure 8

CAZy enrichment analysis top 10 between groups.

Figure 9

PLS-DA analysis of serum metabolites between groups. (A) PLS-DA analysis of SF group and SH group; (B) PLS-DA analysis of SF group and TMR group; (C) PLS-DA analysis of SH group and TMR group.

Figure 10

Differences in purine metabolic pathways between groups. The black box is marked as the intermediate product in the purine metabolic pathway. The black arrow is marked with enzymes annotated in the kegg enzyme database. The red-labeled enzyme is unique in SF and TMR.