Inclusion of Multi-Strained Probiotics Improves the Fecal Microbiota and Carcass Quality of Pigs

Abstract

Limited studies have addressed the effects of multi-strain probiotics on gut microbiota and their influence on meat traits in pigs. Thus, this study investigated the impact of including a commercialized multi-strain probiotic product (SYN) (SYNLAC-LeanAd) into the dietary regimen of crossbred Landrace × Yorkshire × Duroc (LYD) pigs. The study spanned a duration of 22 weeks, from weaning until slaughtering, during which the carcass traits, meat quality, and fecal microbiota profile were compared to those of pigs fed diets with or without an antibiotic growth promoter (AGP). The results demonstrated that the inclusion of SYN significantly improved meat quality parameters, including marbling score, tenderness, and intramuscular fat (p < 0.05) in comparison to pigs fed with AGP. The analysis of fecal microbiota revealed that SYN inclusion increased the populations of Clostridiaceae, Coriobacteriaceae, and Erysipelotrichaceae compared to the control and AGP groups. Additionally, the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis predicted that the amino acid and lipid metabolism pathways were facilitated in pigs from the SYN group. These findings suggest that the inclusion of SYNLAC-LeanAd has the potential to positively impact the fecal microbiota profile, which in turn may lead to improved carcass traits and meat quality in commercial crossbred pigs.

Keywords: carcass quality; marbling; microbiota; probiotic; swine.

Figure 1

IMF distribution and fat area in the LD muscle of pigs. (A) Control group, (B) AGP group, and (C) SYN group after H&E staining under a microscope at 100× magnification. (D) Quantification of the IMF area. The black arrows indicate the IMF. The asterisk (*) indicates a significant difference by the Kruskal–Wallis test (n = 3, p < 0.05).

Figure 2

Relative expression levels of lipid metabolism-associated genes in LD muscle. (A) SREBP-1, (B) FAS, (C) LPL, and (D) CPT-1B. Data are presented as means ± SD and were analyzed by the Mann–Whitney U test (n = 6, p < 0.05). The relative expression levels are the ratio between each group and the control group.

Figure 3

Alpha and beta diversity analyses of the control, AGP, and SYN groups. The alpha diversity box plots show (A) the Shannon indices and (B) the observed ASVs of microbial communities in the three groups. The box plots show the smallest and largest values, 25% and 75% quartiles, and the median. Beta diversity is represented by nonmetric multi-dimensional scaling (NMDS) ordination plots based on (C) weighted and (D) unweighted Unifrac distances of microbial community composition in the three groups. Values with different superscript letters (a, b) were significantly different (p < 0.05).

Figure 4

Fecal microbiota composition of each experimental group. Taxonomic analysis, showing the major classified taxa and the distribution of abundance of microbial taxa at the (A) phylum and (B) family level in three experimental groups, determined by 16S rRNA gene sequencing.

Figure 5

The linear discriminant analysis coupled with effect size (LEfSe) analysis of the fecal microbiota composition. Taxa with significant differences in abundance have an LDA score (log10) > 2.0. The length of the histogram represents the LDA score. Gray indicates taxa enriched in the control group, light blue indicates taxa enriched in the AGP group and orange indicates taxa enriched in the SYN group.

Figure 6

The KEGG functional pathways showing different enrichment among the control, AGP and SYN groups. The abundance of KEGG (A) Level 2 and (B) Level 3 pathways was compared among the three groups using LEfSe. LDA scores (log10) > 2.0 and p < 0.05 are shown. (C) Principal component analysis (PCA) of PICRUSt2 functional predictions. PCA was used to compare the predicted data for Level 3 KEGG pathways.