Piglet and maternal protein diet influence the liver transcriptome in piglets. Piglet and maternal protein diet influence the liver transcriptome in piglets

Introduction The maternal diet is known to affect the offspring’s phenotype, but it is unclear whether the piglet’s response to its own diet depends on maternal diet during late gestation. We investigated how maternal diets with either high or low protein content given during late gestation influences the piglets’ response to a high or low protein nursery diet, and the biological mechanisms that may be affected. Animals, materials and methods A 2x2 factorial trial was used: low (L) vs high (H) crude protein (CP) levels were given to the sows (12 vs 17% CP) at the end of gestation and low vs high CP levels were given to the piglets (16.5 vs 21% CP) from weaning at 3.5 weeks onwards. This resulted in four piglet treatment groups: HH, HL, LH, and LL. All diets were formulated to meet or exceed the nutrient requirements of piglets. At 4.5 weeks of age, 32 (n=8 per treatment) castrated male piglets were sacrificed. RNA-extract from hepatic tissue was sequenced by Quantseq. DESeq2 was used to find differential expression. Differential expressed genes (DEGs) were exported for pathway analyses using g:Profiler [1].Results and discussion A direct effect of piglet diet was seen for 1 DEG, Troponin T (TNNT1), which is involved in slow-skeletal muscle contraction [2]. The sow diet did not result in DEGs in the piglets liver. However, the interaction between maternal and piglet diets resulted in 54 DEGs: 35 upregulated genes in the LL and HH groups, and 19 upregulated genes in the HL and LH groups. Four genes were selected and successfully validated with qPCR. No interesting metabolic pathways were found with g:Profiler. The strongest DEG for this interaction effect was Serum Amyloid A2 (SAA2), which was upregulated in the HL and LH group as compared to the LL and HH group. Porcine SAA is an important acute phase protein and in case of an inflammation increases a 1000-fold in the serum [2]. Prospero Homeobox 1 (PROX1) and forkhead box A1 (FOXA1) are involved in fat metabolism and were both also increased in the HL and LH groups. FOXA1 reduces lipid accumulation in liver cells/hepatocytes [4] and PROX1 has been described to modulate lipid homeostasis [5]. Conclusion An interaction effect was observed between dietary protein levels in the maternal and piglet diet. The gene expression differences found could be linked to either inflammation or lipid metabolism.