Nourishing neonatal piglets with synthetic milk and Lactobacillus sp. at birth highly modifies the gut microbial communities at the post-weaning stage

Abstract

The importance of probiotics in pig production is widely recognized. However, the precise role of probiotics in regulating the gut microbiota of piglets has not been assessed extensively. Therefore, we intend to examine whether suckling pigs ingesting with synthetic milk (SM) and probiotics along with mother milk has a carryover effect on its growth and gut health at the post-weaning stage. A total of 40 [Duroc× (Yorkshire× Landrace)] neonates with an initial BW of 1.49 ± 0.28 kg were assigned to one of two treatments groups: control (CON) and treatment (TRT). Control group piglets were nourished with synthetic milk, while TRT group piglets were nourished SM with (1 × 10⁹ CFU/g) Lactobacillus sp. probiotics. The treatment group piglets showed higher (p < 0.05) body weight and daily gain at week 3 than the CON group piglets. 16S metagenome sequencing showed average demultiplexed reads and denoised reads counts of 157,399 and 74,945, respectively. The total ASV taxonomy number classified with a confidence threshold > 70% (default) on sequence alignment with the SILVA v138 reference database was 4,474. During week 1, Escherichia-Shigella, Clostridium sensu stricto 1, and Bacteroides were confirmed as the major dominant bacterial genera in both the groups at the genus level. However, during week 2, the relative proportion of Escherichia-Shigella, Clostridium sensu stricto 1, and Proteobacteria was decreased, while that of Lactobacillus and Bacteroidota was increased in pigs receiving the probiotic supplement. During weeks 2 and 3, Firmicutes, Proteobacteria, and Bacteroidota phyla were dominant in both groups. During week 6, the relative proportion of Proteobacteria was slightly increased in both groups. Furthermore, Prevotella was confirmed as the major dominant bacterial genus in both groups during weeks 3 and 6. This study suggests that nourishing neonatal piglets with synthetic milk and Lactobacillus sp. probiotics from birth to 21 days would be beneficial to enhance the gut health of piglets and to overcome post-weaning mortality.

Keywords: growth performance; gut microbiome; piglets; probiotics; synthetic milk.

Figure 1

(A,B) Increase in body weight (BW, kg) and ADG (g) of piglets following administration of probiotic supplements. The x- and y-axes (B) indicate the ADG scale, defined as the average weight a market animal will gain each day during the feeding period, and the experimental participant ID, respectively. The black and gray colors denote control and treatment groups, respectively. *Denotes statistically significant p < 0.05.

Figure 2

Alpha-diversity analysis of control and treatment gut microbiome. These box plots show the alpha-diversity estimation scores for each period [(A) week 1, (B) week 2, (C) week 3, and (D) week 6]. Each alpha-diversity was calculated using 1: Observed_ASVs, 2: Chao 1, 3: Shannon_entrophy, 4: Simpson, and 5: Pielou_evenness indices in order.

Figure 3

Beta-diversity analysis of four dependent periods between each piglet. Microbial beta-diversity analysis measured by both Bray–Curtis distance and unweighted UniFrac distance matrix for all samples. Time-series comparison analysis between control and treatment groups at (A) 1, (B) 2, (C) 3, and (D) 6 weeks are represented. The circular clusters represent the distance between control (blue) and treatment (red) groups based on the microbial diversity between the groups and the similarity of the gut microbiomes.

Figure 4

Relative abundance of bacteria at the species level, depending on the duration of probiotic supplement intake [(A) week 1, (B) week 2, (C) week 3, and (D) week 6]. These relative abundance bar plots represent the bacterial composition of piglet gut microbiota at the species level. Each legend box at right annotates the bacterial taxonomy in the order of higher bacterial composition.