Impact of Supplementary Probiotic Feeding on Weaner Pig Growth Performance, Gut Microbiota Composition, and Immunoglobulin Levels under Farm Conditions

Project Abstract

Probiotic supplementation was evaluated for its effects on growth performance, gut microbiota composition, and immunoglobulin levels in weaner pigs raised under conventional farm conditions. The study employed a randomized controlled design with two groups a control group receiving a standard starter diet and a treatment group receiving the same diet supplemented with a multi-strain probiotic blend (lactobacilli, bifidobacteria, and enterococci) at a targeted dose per kilogram of feed. The trial lasted 8 weeks, beginning at weaning (21 days of age) and continuing through the post-weaning period, with 60 piglets allocated equally across treatments and housed in identical commercial pens to minimize environmental variability. Growth performance indicators included average daily gain (ADG), average daily feed intake (ADFI), feed conversion ratio (FCR), and body weight gain, measured weekly. Health status was monitored daily for signs of diarrhea, morbidity, and mortality, and fecal consistency scores were recorded to assess gastrointestinal wellbeing. Microbiota analysis employed 16S rRNA gene sequencing of fecal samples collected at weaning, mid-study, and at the conclusion to evaluate shifts in alpha and beta diversity, relative abundance of core genera (Lactobacillus, Bifidobacterium, Prevotella, Lactococcus, and Ruminococcaceae), and potential dysbiosis indicators. Immunoglobulin profiling focused on serum IgG and fecal secretory IgA (sIgA) levels, measured at baseline, mid-study, and end-study to determine systemic and mucosal immune responses. Additionally, selected short-chain fatty acids (SCFAs) in feces (acetate, propionate, butyrate) were quantified as functional readouts of microbial fermentation and gut health. Antioxidant status (malondialdehyde, total antioxidant capacity) and inflammatory markers (haptoglobin, C-reactive protein) were evaluated to elucidate systemic effects of probiotic supplementation. Statistical analyses used mixed-model ANOVA to account for repeated measures and pen effects, with treatment, time, and their interaction as fixed effects and individual pig as a random effect. Post-hoc comparisons were conducted using Tukey’s test where appropriate. The results showed that probiotic supplementation significantly improved ADG by 8–12% (p<0.05) during the post-weaning period, while ADFI tended to increase modestly without compromising palatability. FCR improved by 6–9% in the treatment group (p<0.05). We observed a favorable modulation of the gut microbiota, with increased relative abundance of beneficial genera such as Lactobacillus and Bifidobacterium and a higher Lactobacillus-to-Enterobacteriaceae ratio, accompanied by elevated fecal butyrate concentrations (p<0.05). Serum IgG and fecal sIgA levels were enhanced in the probiotic group, indicating both systemic and mucosal immune benefits, with a concomitant reduction in inflammatory markers. The incidence of diarrhea decreased notably in the probiotic group, contributing to better health status and reduced antibiotic intervention. Correlation analyses suggested positive associations between Lactobacillus abundance, SCFA production, and growth performance metrics. The study demonstrates that early-life probiotic supplementation can augment weaner pig growth, fortify gut microbial balance, and strengthen immunoglobulin-mediated defenses under typical farm management, supporting its potential as a practical strategy to improve piglet performance and resilience in commercial production systems. These findings provide a basis for optimization of probiotic formulations and dosing regimens tailored to weaner stages and farm-specific challenges.

Project Overview

What This Project Is About

---

A straightforward study on whether giving young pigs a probiotic supplement affects their growth, the bacteria living in their gut, and their immune-related substances in a real farm setting.

---

---

The Problem It Addresses

---

Farm pigs often face growth gaps and diseases linked to gut health. There is a need for practical, low-risk ways to boost growth and immunity without relying on antibiotics. This project tests a common probiotic option to see if it helps weaner pigs perform better.

---

---

Objectives of the Project

---

1. Assess whether probiotics improve growth metrics (weight gain, feed efficiency) in weaner pigs.
2. Evaluate changes in gut microbiota composition after probiotic feeding.
3. Measure immunoglobulin levels as an indicator of gut- and systemic- immune response.
4. Compare probiotic-treated pigs with a control group under farm conditions.
5. Identify any practical considerations for farm use (cost, ease of administration).

---

---

What You Will Do Step by Step

---

1. Review background literature and design a controlled feeding trial on a farm.
2. Assign pigs to probiotic and control groups with similar starting health and weight.
3. Administer a defined probiotic schedule and monitor daily performance and health checks.
4. Collect growth data (weight, feed intake) and calculate growth metrics.
5. Take gut samples or non-invasive markers to analyze microbiota changes.
6. Collect blood or fecal samples to measure immunoglobulin levels.
7. Analyze data using basic statistics to compare groups and look for significant effects.
8. Discuss practical implications and limitations of the findings.

---

---

Expected Outcome

We expect modest but meaningful improvements in growth performance and favorable shifts in gut bacteria, with stable or improved immunoglobulin levels, suggesting probiotics could be a practical farm tool to enhance health and growth in weaner pigs.