Suckling piglet growth performance:
The effect of maternal supplementation on piglet body weight and ADG is presented in Table 3. There was no effect of maternal dietary supplementation on piglet body weight at birth and weaning (P > 0.05), and ADG from birth to weaning (P > 0·05).
Piglet small-intestinal morphology:
The effect of maternal supplementation on piglet small intestinal morphology is presented in Table 4.
Duodenum: Piglets suckling the supplemented sows had larger VH (P <0.05) compared with those suckling the control sows. There was no difference observed in villus height-to-crypt ratio (VH:CD, P>0.05).
Jejunum: There was no difference observed in the morphology between piglets suckling supplemented sows and those suckling the control sows (P>0.05).
Ileum: Piglets suckling supplemented sows had a larger VH:CD ratio (P<0.05) compared with those suckling the control sows.
Gene expression in the small intestine:
The intestinal expression of genes related to nutrient digestion and absorption, mucosal barrier function, and immunity in the duodenum, jejunum and ileum of piglets are presented in Table 5.
Nutrient transporter gene expression
Duodenum: The gene expression of FABP2 (fatty acid binding protein 2, P < 0.01), SLC15A1 (peptide transporter 1, P < 0.01), SLC2A2 (glucose transporter 2, P < 0.05), SLC2A55 (glucose transporter 5, P < 0.05) and SLC1A4 (solute carrier family 1 member 4, P < 0.05) was upregulated in the duodenum of piglets suckling the supplemented sows compared with those suckling the control sows.
Jejunum: The gene expression of FABP2 (P < 0.05), SLC15A1 (P < 0.01), SLC2A5 (P < 0.05), SLC2A2 (P < 0.05), SLC2A5 (P < 0.01), SLC5A1 (sodium transporter 1, P < 0.01) and SLC1A4 (solute carrier family 1 member 4, P < 0.01) was upregulated in the jejunum of piglets suckling the supplemented sows compared with those suckling the control sows. There was a numerical tendency for SLC16A (solute carrier family 16 member 1, P < 0.07) and SLC5A8 (solute carrier family 5 member 8, P < 0.07) to be upregulated in the jejunum of piglets suckling the supplemented sows compared with those suckling the control sows.
Ileum: Nutrient transporter gene expression in the ileal tissue of piglets did not differ between maternal diets (P > 0.05).
Expression of genes involved in inflammation and the epithelial barrier:
Duodenum: The expression of IL6 (interleukin-6, P < 0.05), TNF (tumor necrosis factor, P < 0.05) and TGFB (transforming growth factor beta-1, P < 0.05) were down-regulated in the duodenum of piglets suckling the supplemented sows compared with those suckling the control sows. The expression of CLND3 (claudin-3, P < 0.01) and MUC2 (mucin-2, P < 0.01) were up-regulated in the duodenum of piglets suckling the supplemented sows compared with those suckling the control sows.
Jejunum: The expression of IL10 (interleukin-10, P < 0.01), IL6 (P < 0.0001), TGFB (P < 0.05) and TNF (P < 0.01) were down-regulated in the jejunum of piglets suckling the supplemented sows compared with those suckling the control sows. The expression of CXCL8 (interleukin 8, P < 0.01) and CLND3 (P < 0.0001) were upregulated in the jejunum of piglets suckling the supplemented sows compared with those suckling the control sows.
Ileum: The expression of IFN (interferon gamma, P < 0.05) was downregulated in the ileum of piglets suckling the supplemented sows compared with those suckling the control sows.
The effects of maternal dietary supplementation on the sow faecal and piglet caecal and colonic microbiota
Bacterial Richness and Diversity.
The effects of maternal supplementation on the measures of beta diversity and alpha diversity are presented in Figure 1 and Table 6, respectively. Beta diversity in the piglets caecal and colonic microbiome differed to that of the sow (P<0.05) based on Permanova analysis and through visualisation using the Bray Curtis distance matrix and multi-dimensional scaling. Maternal dietary supplementation had no effect on the Observed, Chao1, ACE, Shannon, Simpson, InvSimpson and Fisher index measures of alpha diversity (P>0.05) in either the sows faeces or the piglets caecal and colonic digesta.
Differential Bacterial Abundance analysis.
All data on bacterial abundances at phylum, family and genus level are provided in Tables 7, 8 and 9.
Phylum
Sow faeces:
There were six bacterial phyla identified with Firmicutes being the dominant phyla (~87.69%) followed by Proteobacteria (~6.52%), Spirochaetes (~3.50%), Actinobacteria (~1.38%), Tenericutes (~0.47%), and Synergistetes (~0.10%). Firmicutes were increased (P<0.05) and Proteobacteria were decreased (P<0.05) in the supplemented sows compared to the control sows.
Piglet Caecum:
There were seven bacterial phyla identified with Firmicutes being the dominant phyla (~86.80%) followed by Actinobacteria (~7.89%), Proteobacteria (~4.57%), Verrucomicrobia (~0.55%), Fusobacteria (~0.06%), and Bacteroidetes (~0.01%). Actinobacteria and Verrucomicrobia were decreased (P<0.05) in piglets from supplemented sows compared to piglets from control sows.
Piglet colon:
There were six bacterial phyla identified with Firmicutes being the dominant phyla (~90.47%) followed by Actinobacteria (~6.65%), Proteobacteria (~2.43%), Fusobacteria (~0.09%), and Verrucomicrobia (~0.06%). The relative abundance of Actinobacteria was decreased (P<0.05) in piglets from supplemented sows compared to piglets from control sows.
Family
Sow faeces:
At family level, dietary supplementation increased the relative abundance of Lactobacillaceae (P<0.0001) and Lachnospiraceae (P<0.05) within the Firmicutes phylum compared with the control group. Dietary supplementation decreased the relative abundance of Christensenellaceae (P<0.05), and Planococcaceae (P<0.05) within the Firmicutes phylum and Moraxellaceae (P<0.0001) within the Proteobacteria phylum compared to the control.
Piglet caecum:
At family level, the relative abundance of Erysipelotrichaceae, Lactobacillaceae, Oscillospiraceae, and Christensenellaceae within the Firmicutes phylum were increased (P<0.05) in piglets from supplemented sows compared to piglets from control sows. The relative abundance of Coriobacteriaceae and Atopobiaceae within the Actinobacteria phylum, Ruminococcaceae within the Firmicutes phylum, and Akkermansiaceae within the Verrucomicrobia phylum were decreased (P<0.05) in piglets from supplemented sows compared to piglets from control sows.
Piglet colon:
At family level, the relative abundance of Erysipelotrichaceae and Christensenellaceae within the Firmicutes phylum were increased (P<0.05) in piglets from supplemented sows compared to piglets from control sows. The relative abundance of Atopobiaceae within the Actinobacteria phylum was decreased (P<0.05) in piglets from supplemented sows compared to piglets from control sows.
Genus
Sow faeces:
At genus level, dietary supplementation increased the relative abundance of Lactobacillus (P<0.001), Metabacterium (P<0.01) and Niameybacter (P<0.01) within the Firmicutes phylum, and Gemmiger (P<0.05) within the Proteobacteria phylum compared to the control. Dietary supplementation decreased the relative abundance of Christensenella (P<0.05) within the Firmicutes phylum, Kineothrix (P<0.05) within the Lachnospiraceae phylum, and Acinetobacter (P<0.0001) within the Proteobacteria phylum compared to the control.
Piglet caecum:
At genus level, the relative abundance of Flavonifractor, Lactobacillus,Holdemania, Oscillibacter and Christensenella within the Firmicutes phylum were increased (P<0.05) in piglets from supplemented sows compared to piglets from control sows. The relative abundance of Collinsella and Olsenella within the Actinobacteria phylum, Intestinimonas and Ruminococcus within the Firmicutes phylum, and Gemmiger within the Proteobacteria phylum were decreased (P<0.05) in piglets from supplemented sows compared to piglets from control sows.
Piglet colon:
At genus level, the relative abundance of Flavonifractor, Holdemania, Ruminococcus and Christensenella within the Firmicutes phylum were increased (P<0.05) in piglets from supplemented sows compared to piglets from control sows. The relative abundance of Gemmiger within the Proteobacteria phylum and Olsenella within the Actinobacteria phylum were decreased (P<0.05) in piglets from supplemented sows compared to piglets from control sows.