Differences in intestinal and renal Ca and P uptake in three different breeds of growing-finishing pigs

Abstract

This study investigated the differences in bone growth and turnover and calcium (Ca) and phosphorus (P) uptake among three different breeds of growing-finishing pigs. Ninety healthy Duroc, Xiangcun black (XCB), and Taoyuan black (TYB) pigs (30 pigs per breed) at 35 day-old (D) with the average body weight (BW) of their respective breed were assigned and raised to 185 D. The results showed that Duroc pigs had higher bone weight and length than the XCB and TYB pigs at 80, 125, and 185 D and the bone index at 185 D (p < 0.05). Duroc pigs had higher bone mineral densities (femur and tibia) compared with the other two breeds at 80 D and 125 D, whereas TYB pigs had higher mineral content and bone breaking load (rib) compared with the other two breeds at 185 D (p < 0.05). The bone morphogenetic protein-2 and osteocalcin concentrations were higher, and TRACP5b concentration was lower in serum of TYB pigs at 125 D (p < 0.05). Meanwhile, 1,25-dihydroxyvitamin D₃, parathyroid hormone, thyroxine, and fibroblast growth factor 23 concentrations were higher in serum of TYB pigs at 185 D (p < 0.05). The TYB pigs had higher apparent total tract digestibility of P at 80 D and 185 D and bone Ca and P contents at 185 D in comparison to the Duroc pigs (p < 0.05). Furthermore, gene expressions related to renal uptake of Ca and P differed among the three breeds of pigs. Collectively, Duroc pigs have higher bone growth, whereas TYB pigs have a higher potential for mineral deposition caused by more active Ca uptake.

Keywords: Breed; bone characteristics; calcium; growing-finishing pigs; phosphorus.

Figure 1.

Differences in bone ash content among three breeds of growing-finishing pigs. Values are shown as means with their SEM. The replicates at 80, 125, and 185 D were six pigs per breed. Different small letters (a, b, and c) indicate significant differences among different pig breeds at the same day-old (p < 0.05). 80, 125, and 185 D, represent 80, 125, and 185 day-old, respectively.

Figure 2.

Differences in serum concentrations of osteogenesis factors (A–D) and bone resorption markers (E–F) among three breeds of growing-finishing pigs. Different small letters (a and b) indicate significant differences among different pig breeds at the same day-old (p < 0.05). 80, 125, and 185 D, represent 80, 125, and 185 day-old, respectively. BMP-2 = bone morphogenetic protein-2; BALP = bone alkaline phosphatase; OC = osteocalcin; PINP = procollagen I N-terminal propeptide; TRACP 5b = tartrate-resistant acid phosphatase 5b; CTX-1 = type I collagen carboxy-terminal peptide. The replicates of Duroc, XCB, and TYB pigs at 80 D were 9, 9, and 10, respectively. The replicates of Duroc, XCB, and TYB pigs at 125 D were 9, 9, and 8, respectively. The replicates of Duroc, XCB, and TYB pigs at 185 D were 9, 10, and 9, respectively.

Figure 3.

Differences in bone Ca (A) and P (B) contents among three breeds of growing-finishing pigs. The replicates at 80, 125, and 185 D were six per breed. Different small letters (a and b) indicate significant differences among different pig breeds at the same day-old (p < 0.05). 80, 125, and 185 D, represent 80, 125, and 185 day-old, respectively.

Figure 4.

Differences in serum indicators related to Ca (A–C) and P (D–E) metabolism among three breeds of growing-finishing pigs. Different small letters (a and b) indicate significant differences among different pig breeds at the same day-old (p < 0.05). The replicates of duroc, XCB, and TYB pigs at 80 D were 9, 9, and 10, respectively. The replicates of duroc, XCB, and TYB pigs at 125 D were 9, 9, and 8, respectively. The replicates of duroc, XCB, and TYB pigs at 185 D were 9, 10, and 9, respectively. 80, 125, and 185 D represent 80, 125, and 185 day-old, respectively. CT = calcitonin; PTH = parathyroid hormone; T4 = thyroxine; FGF23 = fibroblast growth factor 23.

Figure 5.

Differences in mRNA expressions of Ca and P transporters in the kidney (a), duodenum (B), jejunum (C), and ileum (D) of three different breeds of pigs at 80 day-old (D). The replicates were eight pigs per breed. Different small letters (a, b and c) indicate significant differences among different pig breeds (p < 0.05). Napi-IIa = sodium-dependent phosphate transport protein 2a; Napi-IIb = sodium-dependent phosphate transport protein 2b; S100G = S100 calcium binding protein G; PMCA1 = plasma membrane calcium-transporting ATPase 1; SLC8A1 = solute carrier family 8 member 1; TRPV5 = transient receptor potential cation channel, subfamily V, member 5; TRPV6 = transient receptor potential cation channel, subfamily V, member 6; CALB1 = calbindin 1; VDR = vitamin D receptor.

Figure 6.

Differences in mRNA expressions of Ca and P transporters in the kidney (a), duodenum (B), jejunum (C), and ileum (D) of three different breeds of pigs at 125 day-old (D). The replicates were eight pigs per breed. Different small letters (a and b) indicate significant differences among different pig breeds (p < 0.05). Napi-IIa = sodium-dependent phosphate transport protein 2a; Napi-IIb = sodium-dependent phosphate transport protein 2b; S100G = S100 calcium binding protein G; PMCA1 = plasma membrane calcium-transporting ATPase 1; SLC8A1 = solute carrier family 8 member 1; TRPV5 = transient receptor potential cation channel, subfamily V, member 5; TRPV6 = transient receptor potential cation channel, subfamily V, member 6; CALB1 = calbindin 1; VDR = vitamin D receptor.

Figure 7.

Differences in mRNA expressions of Ca and P transporters in the kidney (a), duodenum (B), jejunum (C), and ileum (D) of three different breeds of pigs at 185 day-old (D). The replicates were eight pigs per breed. Different small letters (a and b) indicate significant differences among different pig breeds. Napi-IIa = sodium-dependent phosphate transport protein 2a; Napi-IIb = sodium-dependent phosphate transport protein 2b; S100G = S100 calcium binding protein G; PMCA1 = plasma membrane calcium-transporting ATPase 1; SLC8A1 = solute carrier family 8 member 1; TRPV5 = transient receptor potential cation channel, subfamily V, member 5; TRPV6 = transient receptor potential cation channel, subfamily V, member 6; CALB1 = calbindin 1; VDR = vitamin D receptor.