📄 agriculture

Probiotic additives (Lacticaseibacillus rhamnosus RC007 and Lactiplantibacillus plantarum RC009) modulates gut microbiota and systemic biochemical markers associated with improved growth performance in post weaning pigs under field conditions

This field study demonstrates that supplementing post-weaning pig diets with *Lacticaseibacillus rhamnosus* RC007 or *Lactiplantibacillus plantarum* RC009 significantly improves growth performance by modulating gut microbiota composition, metabolic functions, and systemic biochemical markers.

Original authors: Maite Corti Isgro, Alejandra Paola Magnoli, Valeria Lorena Poloni, María Julieta Luna, Dardo Roma, Laureano Giordano, Danilo Ceschin, Mañas Fernando, Alicia Carranza, Lilia Renée Cavaglieri, Julián Pa

Published 2026-07-09

📖 5 min read🧠 Deep dive

CC BY 4.0

Original authors: Maite Corti Isgro, Alejandra Paola Magnoli, Valeria Lorena Poloni, María Julieta Luna, Dardo Roma, Laureano Giordano, Danilo Ceschin, Mañas Fernando, Alicia Carranza, Lilia Renée Cavaglieri, Julián Parada

Original paper licensed under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). ✨ This is an AI-generated explanation of the paper below. It is not written or endorsed by the authors. For technical accuracy, refer to the original paper. Read full disclaimer

Imagine a piglet's life is like a student starting a new, stressful school year. The "weaning" phase (when they stop nursing and start eating solid food) is like that first week of school: they are separated from their mom, moved to a new classroom, mixed with kids from other classes, and forced to eat a completely different lunch. This causes a lot of stress, which can make their "gut garden" (their digestive system) chaotic, leading to poor growth and sickness.

For a long time, farmers have used antibiotics to keep these gut gardens tidy and help the pigs grow. But just like overusing medicine in humans, this has created "superbugs" that are hard to kill. So, scientists are looking for a natural way to help the pigs' guts thrive without antibiotics.

This paper is about a field test where researchers tried two different "probiotic helpers" (good bacteria) to see if they could act as a better substitute for antibiotics.

The Experiment: The Three Teams

The researchers set up a large commercial pig farm and divided the piglets into three teams:

The Control Team (CG): Ate a standard diet with no special additives.
The LP9 Team: Ate the standard diet plus a specific probiotic called Lactiplantibacillus plantarum (RC009). Think of this as adding a specific type of "garden fertilizer" to their food.
The LR7 Team: Ate the standard diet plus a different probiotic called Lacticaseibacillus rhamnosus (RC007). This is a different kind of "fertilizer."

They tracked these pigs from the moment they were weaned (21 days old) until they were about 70 days old. They weighed them, checked their blood, and even took poop samples to see what was living inside their guts.

What They Found: The Results

1. The Growth Race

The LR7 Team (The Star Performer): These pigs were the clear winners. By the end of the study, they were significantly heavier than the Control Team. On average, they gained about 2.2 kg (nearly 5 lbs) more than the pigs on the standard diet. They grew faster and more consistently throughout the whole period.
The LP9 Team (The Slow Starter): These pigs had a bumpy ride. At the very beginning, they actually grew a little slower than the Control Team. However, they caught up and eventually ended up slightly heavier than the Control Team by the end. The researchers suggest this might be because the pigs' digestive systems needed a little extra time to get used to this specific type of bacteria.
The Control Team: They grew normally, but not as well as the LR7 team.

2. The Blood Check-Up
The researchers looked at the pigs' blood to see how healthy their internal organs were.

Stress Levels: They measured a marker called MDA, which is like a "rust indicator" showing how much damage stress is doing to the body. Both probiotic teams had lower "rust" levels at the start, suggesting less stress damage, though this difference faded a bit by the end.
Liver and Cholesterol: The study found that the pigs eating the probiotics had better liver function markers and cholesterol levels compared to the control group. Specifically, the LR7 team showed a strong link between their improved growth and healthier blood chemistry.

3. The Gut Garden (Microbiota)
The researchers took a deep look at the bacteria living in the pigs' poop (which represents the gut).

The Control Team: Their gut bacteria looked a bit more chaotic and varied, with some "weeds" (less helpful bacteria) appearing more often.
The LR7 Team: Their gut bacteria formed a very tight, organized group. It was as if the probiotic helped the good bacteria stick together and crowd out the bad ones. They saw an increase in bacteria that are good at breaking down plant fibers and producing energy (like butyrate).
The LP9 Team: Their gut looked very similar to the Control Team, meaning this specific probiotic didn't drastically change the bacterial lineup, even though the pigs still grew a bit better in the long run.

4. The Hidden Factory (Metabolic Pathways)
Using computer modeling, the researchers predicted what the bacteria were capable of doing. They found that the probiotic teams had a gut microbiome that was genetically "programmed" to be better at making essential amino acids (the building blocks of protein). It's like the probiotic team's gut bacteria had a better blueprint for building muscle and growing, even if we didn't measure the actual building blocks directly.

The Bottom Line

This study shows that adding specific "good bacteria" to pig feed can help them grow bigger and healthier during the stressful weaning period, potentially replacing the need for antibiotics.

L. rhamnosus (RC007) was the standout champion, making pigs grow faster, stay healthier, and organize their gut bacteria better.
L. plantarum (RC009) also helped, but it took the pigs a little longer to get used to it before they started growing faster.

The paper concludes that these probiotics work by changing the "gut garden" and improving the body's internal chemistry, leading to better growth performance in real-world farm conditions.

Technical Summary: Probiotic Additives in Post-Weaning Pigs

Problem Statement
The post-weaning phase in intensive pig production (typically 21–28 days of age) represents a critical period characterized by physiological, immunological, and nutritional stress. Piglets face abrupt transitions from a milk-based liquid diet to solid feed, separation from the sow, and commingling with other litters. These stressors often lead to intestinal inflammation, increased mucosal permeability, reduced feed intake, impaired growth, and diarrhea. Historically, non-therapeutic antibiotics have been used to mitigate these issues and improve average daily gain (ADG); however, their indiscriminate use has driven the emergence of multidrug-resistant bacteria, necessitating effective alternatives. While probiotics have emerged as a potential solution, their efficacy is often strain-dependent, and improvements in productive performance are not consistently observed across studies. Furthermore, the specific mechanisms by which probiotics influence systemic biochemical markers and gut microbiota composition in field conditions remain under-explored.

Methodology
The study was conducted as a field trial in a commercial three-site pig farm in Córdoba, Argentina, involving 1,187 pigs in the control group (CG) and approximately 1,100 pigs in each probiotic treatment group. The trial spanned the entire post-weaning period (from 21 to 70 days of age).

Experimental Design: Three treatment groups were established:
- CG: Standard diet.
- LP9: Standard diet + Lactiplantibacillus plantarum RC009 ( $1 \times 10^{12}$ CFU/kg feed).
- LR7: Standard diet + Lacticaseibacillus rhamnosus RC007 ( $1 \times 10^{12}$ CFU/kg feed).
- Note: All groups received routine antibiotic treatments (florfenicol and doxycycline) in drinking water during specific intervals, allowing for the evaluation of probiotic effects in the context of antibiotic administration.
Data Collection:
- Productive Parameters: Individual weights were recorded at days 0, 10, 24, and 48 for a subpopulation of 60 pigs per treatment. Group-level weights and mortality were tracked for the entire barn populations. Average Daily Gain (ADG) and Feed Conversion Ratio (FCR) were calculated.
- Biochemical Analysis: Blood samples were collected at days 24 and 48 to measure total protein, albumin, globulins (via electrophoresis), cholesterol, alanine aminotransferase (ALT), aspartate aminotransferase (AST), and malondialdehyde (MDA) as an oxidative stress marker.
- Microbiota Analysis: Fecal samples were collected from 16 animals per treatment at day 20 (pre-antibiotic) and day 48. Samples underwent 16S rRNA gene sequencing (NGS). Bioinformatic analysis included taxonomic profiling (Kraken2/Bracken), diversity analysis (Shannon/Simpson indices, PCoA), and functional prediction (PICRUSt2) to infer metabolic pathways.
Statistical Analysis: Data were analyzed using Generalized Linear Mixed Models (GLMM) and ANOVA, with animal identification as a random effect and group/time as fixed effects.

Key Results

Growth Performance:
- LR7 Group: Pigs receiving L. rhamnosus RC007 demonstrated significantly higher body weights throughout the study compared to the control group ( $p < 0.05$ ). At the end of the trial, the estimated weight gain effect was +2.19 kg (±0.45) compared to CG. This group also showed a significantly higher Total ADG (0.53 ± 0.06 kg vs. 0.48 ± 0.07 kg) and a marginal improvement in FCR (1.32 vs. 1.45).
- LP9 Group: Pigs receiving L. plantarum RC009 showed a delayed response. They initially had lower weights at day 10 compared to CG but recovered to show significantly higher final weights (+1.01 kg ± 0.44) by day 48. Their overall ADG increase was not statistically significant compared to CG.
- Mortality: Both probiotic groups exhibited slightly lower mortality rates (0.63% for LR7, 0.68% for LP9) compared to the control group (0.93%).
Biochemical Markers:
- Oxidative Stress: Plasma MDA levels were significantly lower in both probiotic groups at the first sampling (day 24), though this difference was not statistically significant at day 48.
- Liver Function and Lipids: A generalized linear mixed model identified that blood cholesterol and ALT levels were significantly negatively associated with ADG. Specifically, the LP9 group showed a clear decrease in both cholesterol and ALT over time, whereas the LR7 group showed an increase in cholesterol.
- Proteins: Probiotic consumption altered serum protein profiles, with specific variations in $\alpha$ -globulin fractions observed in the LP9 group and $\beta$ -globulins in the LR7 group.
Gut Microbiota Composition:
- Diversity: No significant differences were found in alpha diversity between groups, though probiotic groups showed lower dispersion in diversity indices. Beta diversity analysis (PCoA) revealed that the LR7 group clustered distinctly from the control group, particularly at day 48, whereas the LP9 group remained similar to the control.
- Taxonomy: The predominant phyla were Firmicutes and Bacteroidota. The LR7 group was characterized by an increase in Prevotella_7 and Streptococcaceae (facultative anaerobes). The LP9 group showed an increase in Lachnospiraceae (including Lachnospiraceae NK4A136 group) and Prevotellaceae NK3B31 group.
- Functional Prediction: PICRUSt2 analysis indicated that the control group had a higher predicted abundance of metabolic pathways related to amino acid biosynthesis (e.g., lysine, methionine, valine, leucine) compared to the probiotic groups. This suggests that probiotic consumption may alter the genetic potential of the microbiota regarding amino acid metabolism.

Significance and Claims
The authors claim that the study evidences the capacity of L. rhamnosus RC007 and L. plantarum RC009 to improve the growth of pigs during the post-weaning period under field conditions. The improvement in growth performance, particularly with the LR7 strain, is associated with:

Modification of Fecal Microbiota: Specifically, the enrichment of beneficial taxa such as Lachnospiraceae and Prevotella groups, which are linked to anti-inflammatory activity and short-chain fatty acid production.
Systemic Biochemical Changes: Alterations in oxidative stress markers (MDA) and liver function indicators (ALT, cholesterol).
Metabolic Potential: Changes in the predicted genetic potential of the gut microbiome regarding metabolic pathways, suggesting a shift in how the microbial community processes nutrients.

The paper concludes modestly, noting that while the study demonstrates a correlation between probiotic consumption, microbiota modification, and improved growth, further research is required to confirm whether these changes in genetic potential directly impact the metabolites available to the animal and to fully elucidate the mechanisms driving the observed performance differences. The study highlights the strain-dependent nature of probiotic efficacy, noting that L. rhamnosus RC007 provided more consistent growth benefits than L. plantarum RC009 in this specific field setting.

The Experiment: The Three Teams

What They Found: The Results

The Bottom Line

Technical Summary: Probiotic Additives in Post-Weaning Pigs

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