Serum biochemical parameters and amino acids metabolism are altered in piglets by early-weaning and proline and putrescine supplementations

Abstract

The study was to investigate the effect of early-weaning stress and proline (Pro) and putrescine (Put) supplementations on serum biochemical parameters and amino acids (AA) metabolism in suckling and post-weaning pigs. Blood and small intestinal mucosa were harvested from suckling piglets at 1, 7, 14, and 21 d of age and piglets on d 1, 3, 5, and 7 after weaning at 14 d of age, as well as from piglets received oral administration of Pro and Put from 1 to 14 d old. In suckling piglets, the serum glucose, albumin and total cholesterol levels were increased (P < 0.05) with increasing age, whereas the serum globulin, urea nitrogen (BUN), alkaline phosphatase (ALP) and aspartate aminotransferase (AST) levels were lowered (P < 0.05). The concentrations of most serum AA and the AA transporters related gene expressions were highest in 7-d-old piglets (P < 0.05), whereas the phosphorylation status of the mammalian target of the rapamycin (mTOR) signaling pathway in the small intestine increased in piglets from 1 to 21 d old (P < 0.05). Weaning at 14 d old increased (P < 0.05) the BUN and triglycerides levels in serum, as well as jejunal solute carrier family 7 member 6 (SLC7A6), ileal SLC36A1 and SLC1A1 mRNA abundances at d 1 or 3 post-weaning. Weaning also inhibited (P < 0.05) the phosphorylation levels of mTOR and its downstream ribosomal protein S6 kinase 1 (S6K1) and 4E-binding protein-1 (4EBP1) in the small intestine of weanling pigs. Oral administration of Put and Pro decreased (P < 0.05) serum ALP levels and increased (P < 0.05) intestinal SLC36A1 and SLC1A1 mRNA abundances and mTOR pathway phosphorylation levels in post-weaning pigs. Pro but not Put treatment enhanced (P < 0.05) serum Pro, arginine (Arg) and glutamine (Gln) concentrations of weaning-pigs. These findings indicated that early-weaning dramatically altered the biochemical blood metabolites, AA profile and intestinal mTOR pathway activity, and Pro and Put supplementations improved the AA metabolism and transportation as well as activated the intestinal mTOR pathway in weanling-pigs. Our study has an important implication for the broad application of Pro and Put in the weaning transition of piglets.

Keywords: Amino acid; Piglet; Proline; Putrescine; Weaning; mTOR signaling pathway.

Fig. 1

The study design of trail 1 and trial 2. w = post-weanling.

Fig. 2

Concentrations of serum biochemical metabolites and enzymes in suckling and weanling piglets. (A) glucose, (B) albumin, (C) globulin, (D) aspartate aminotransferase (AST), (E) alkaline phosphatase (ALP), (F) urea nitrogen, (G) triglycerides, (H) total cholesterol, (I) creatinine, (J) high density lipoprotein (HDL), (K) low-density lipoprotein (LDL), (L) very low-density lipoprotein (VLDL). Data are expressed as means ± SEM, n = 8. ^a-d Bars with different letters are significantly different (P < 0.05).

Fig. 2

Concentrations of serum biochemical metabolites and enzymes in suckling and weanling piglets. (A) glucose, (B) albumin, (C) globulin, (D) aspartate aminotransferase (AST), (E) alkaline phosphatase (ALP), (F) urea nitrogen, (G) triglycerides, (H) total cholesterol, (I) creatinine, (J) high density lipoprotein (HDL), (K) low-density lipoprotein (LDL), (L) very low-density lipoprotein (VLDL). Data are expressed as means ± SEM, n = 8. ^a-d Bars with different letters are significantly different (P < 0.05).

Fig. 3

Effects of putrescine and proline supplementation on serum biochemical metabolites and enzyme levels in piglets. (A) glucose, (B) albumin, (C) globulin, (D) aspartate aminotransferase (AST), (E) alkaline phosphatase (ALP), (F) urea nitrogen, (G) triglycerides, (H) total cholesterol, (I) creatinine, (J) high density lipoprotein (HDL), (K) low density lipoprotein (LDL), (L) very low-density lipoprotein (VLDL). Data are expressed as means ± SEM, n = 6. ^{a, b} Bars with different letters are significantly different (P < 0.05).

Fig. 3

Effects of putrescine and proline supplementation on serum biochemical metabolites and enzyme levels in piglets. (A) glucose, (B) albumin, (C) globulin, (D) aspartate aminotransferase (AST), (E) alkaline phosphatase (ALP), (F) urea nitrogen, (G) triglycerides, (H) total cholesterol, (I) creatinine, (J) high density lipoprotein (HDL), (K) low density lipoprotein (LDL), (L) very low-density lipoprotein (VLDL). Data are expressed as means ± SEM, n = 6. ^{a, b} Bars with different letters are significantly different (P < 0.05).

Fig. 4

Relative mRNA levels of amino acids transporters in the jejunal and ileal mucosa of suckling and weanling pigs. (A) solute carrier family 7 member 6 (SLC7A6), (B) SLC7A7, (C) proton-assisted AA transporter 1 (SLC36A1), (D) excitatory AA transporter 3 (SLC1A1). Data are expressed as means ± SEM, n = 8. w = post-weanling. ^a–d Bars with different letters are significantly different (P < 0.05).

Fig. 5

Effects of putrescine and proline supplementation on AA transporter mRNA levels of jejunal and ileal mucosa in piglets. (A) solute carrier family 7 member 6 (SLC7A6), (B) SLC7A7, (C) proton-assisted AA transporter 1 (SLC36A1), (D) excitatory AA transporter 3 (SLC1A1). Data are expressed as means ± SEM, n = 8. ^{a, b} Bars with different letters are significantly different (P < 0.05).

Fig. 6

Protein abundances of mTOR signaling pathway in jejunal mucosa of piglets. (A) Representative western blots and relative protein abundances of mTOR, p-mTOR, p70S6K, p-p70S6K, 4EBP1, p-4EBP1, and β-Actin in jejunal mucosa of suckling and weanling piglets. (B) Representative western blots and relative protein abundances of mTOR, p-mTOR, p70S6K, p-p70S6K, 4EBP1, p-4EBP1, and β-Actin in jejunal mucosa of piglets treated with putrescine and proline; n = 6. mTOR = mammalian target of rapamycin; p-mTOR = phosphorylation mTOR; p70S6K = phosphoprotein 70 ribosomal protein S6 kinase-1; 4EBP1 = eIF4E-binding protein-1; p-4EBP1 = phosphorylation 4EBP1; w = post-weanling; Data are expressed as means ± SEM, n = 8. ^a–e Bars with different letters are significantly different (P < 0.05).