# Effect of Dead-Cell Limosilactobacillus ingluviei on Hematological Parameters and Jejunal Transcriptome Profile in Calves During the Weaning Period

## TL;DR

A postbiotic from dead-cell Limosilactobacillus ingluviei improves gut and immune health in calves during weaning by reducing inflammation and enhancing nutrient absorption.

## Contribution

This study reveals novel molecular mechanisms of a postbiotic in improving gut health and immune function in calves during weaning.

## Key findings

- Postbiotic supplementation reduced inflammation markers like globulin and neutrophil levels in calves.
- Transcriptomic analysis showed upregulation of genes involved in fatty acid metabolism, gut barrier function, and detoxification.
- The postbiotic improved pathways related to glutathione metabolism and nutrient absorption in the jejunum.

## Abstract

Weaning is a stressful period for young calves, and it often leads to digestive and immune challenges. To help improve gut health during this transition, this study aimed to investigate the effects of a postbiotic from dead-cell Limosilactobacillus ingluviei C37 on the hematology and jejunal epithelial transcriptomes. The calves fed with this postbiotic showed lower levels of inflammation-related blood markers and beneficial changes in genes related to gut protection, nutrient utilization, and detoxification. These results suggest that postbiotics may help support the gut and immune health of calves during weaning, offering a safer alternative to traditional probiotics.

Weaning is challenging for dairy calves, frequently resulting in digestive issues. This highlights the importance of implementing appropriate nutritional strategies to enhance gut health and support optimal growth. Postbiotics is a promising alternative to traditional probiotics, conferring health benefits without the risks associated with live bacteria. This study aimed to investigate the effect of dietary supplementation with a postbiotic from dead-cell Limosilactobacillus ingluviei C37 (postbiotic LIC37) on blood biochemical parameters and jejunal epithelium transcriptomic profiles in calves. Fourteen Holstein bull calves were randomly allocated into two groups (n = 7). The control group (CON) received a basic diet, while the postbiotic group (DCLI) was supplemented with 1 g/d of postbiotic LIC37 for 90 days. Blood samples were collected on days 76, 83, and 90, respectively. The jejunal epithelial tissue was obtained from four randomly selected calves per group at day 90 for transcriptome analysis. The results showed that postbiotic LIC37 supplementation reduced globulin, total protein, neutrophil (Neu) levels, and neutrophil-to-lymphocyte ratio (NLR) levels in the DCLI group (p < 0.05). Transcriptomic analysis identified 76 differentially expressed genes (DEGs), with significant upregulation of genes involved in fatty acid metabolism (FABP1), intestinal barrier function (B4GALNT2), and detoxification (GSTA1), alongside downregulation of immune response regulation (FCRLA, FCRL4). Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses highlighted enrichment in pathways related to glutathione metabolism, drug metabolism, and vitamin digestion, indicating that postbiotic supplementation improved detoxification, oxidative stress defense, and nutrient absorption in calves. This study provides novel insights into the molecular mechanisms underlying the benefits of postbiotic LIC37 and supports its potential as a sustainable alternative to probiotics in calf nutrition.