# Low-Protein-Fed Chickens Benefit from Probiotic L. salivarius and L. johnsonii on Performance and Microbiota

## TL;DR

This study shows that adding two probiotic bacteria to a low-protein chicken diet improves growth, gut health, and microbial balance in Baicheng You chickens.

## Contribution

The study introduces a novel probiotic combination from human infant feces that enhances poultry performance on low-protein diets.

## Key findings

- Probiotic supplementation increased feed intake, daily gain, and improved feed conversion in chickens.
- The probiotics enhanced antioxidant status and improved intestinal morphology, including villus height and villus-to-crypt ratio.
- Microbial diversity increased, with beneficial bacteria rising and harmful ones decreasing in the cecum.

## Abstract

The present study isolated bacterial strains with potential probiotic properties from human infant feces (aged 0–6 months) and subsequently evaluated the combined effects of strains Lactobacillus salivarius TRM58163 and Lactobacillus johnsonii TRM59525 on 100-day-old Baicheng You chickens maintained on a low-protein diet. Supplementation with these two strains increased feed intake and average daily gain (ADG), and improved the feed conversion ratio; furthermore, enhanced antioxidant status and the villus-to-crypt ratio were elevated. The treated birds exhibited greater intestinal microbial diversity, expansion of beneficial taxa, and a reduction in potentially harmful microorganisms. These findings provide preliminary evidence that this probiotic combination enhances production performance and modulates the intestinal microbiota of Baicheng You chickens, demonstrating its potential value as a functional additive for low-protein poultry diets.

This study aimed to evaluate the combined effects of two probiotic strains, Lactobacillus salivarius TRM58163 and Lactobacillus johnsonii TRM59525—originally isolated from human infant feces (aged 0–6 months)—on growth performance, antioxidant capacity, liver function, intestinal morphology, and cecal microbiota in 100-day-old Baicheng You chickens fed a low-protein diet. Ten strains isolated from infant feces were initially screened, and eight were assessed in vitro for safety, gastrointestinal tolerance, and antimicrobial activity. TRM58163 and TRM59525 showed the best probiotic potential. A total of 240 Baicheng You chickens (100 days old) were randomly assigned to two groups: The control group was fed a low-protein diet (CLD), while the experimental group had Lactobacillus salivarius TRM58163 and Lactobacillus johnsoni TRM59525 added to the low-protein diet (LLD, ≥1 × 109 CFU/g feed). Each treatment included four replicates of 30 chickens over 42 days. Probiotic supplementation significantly improved average daily feed intake (ADFI), average daily gain (ADG), and feed conversion ratio (FCR) (p < 0.05). It also enhanced antioxidant status, with increased plasma superoxide dismutase activity and reduced malondialdehyde levels. Lower total bilirubin levels indicated improved liver function. The LLD group showed increased ileal villus height and villus-to-crypt ratio. 16S rRNA gene sequencing revealed greater microbial diversity, increased beneficial genera (e.g., Akkermansia, Bacteroides), and decreased harmful taxa (e.g., Sutterella). These microbial shifts were associated with improved growth and metabolic profiles. In conclusion, L. salivarius TRM58163 and L. johnsonii TRM59525 supplementation improved performance, gut health, and microbial composition, supporting their use as functional probiotics in low-protein poultry diets.