Protein turnover during pregnancy

Abstract

The response of whole body protein turnover in sows to increasing dietary threonine (THR) during pregnancy was determined using continuous oral delivery of L[1‐13C]phenylalanine (PHE) in six multiparous sows. Pregnancy (115 d) was divided into early (35 to 53 d) and late (93 to 110 d) gestation. Sows received diets with 4.9 ‐ 16.1 gd−1 THR. Blood was sampled every 30 min for 4 h. Data was analyzed with a nonlinear Mixed model.In early pregnancy, THR intake did not affect protein turnover. However, when expressed as a percent of flux, protein synthesis increased (R2=0.84) and PHE oxidation decreased (R2=0.79) at THR intakes below the dietary requirement. In late pregnancy, PHE oxidation decreased (R2=0.40) and protein synthesis increased (R2=0.40) linearly. The THR requirement based on protein synthesis in early pregnancy was 2‐fold lower (6.0 gd−1) than in late pregnancy (>14.0 gd−1). There was no difference between early and late pregnancy in total protein breakdown (p=0.27, 44.1 ± 2.2 vs 46.2 ± 2.3 gd−1, respectively) and PHE flux (p=0.12, 57.0 ± 2.5 vs 60.0 ± 2.6 gd−1, respectively). However, PHE flux/kg BW was higher in early pregnancy compared to late pregnancy (82.2 ± 2.1 vs 71.2 ± 2.2 gd−1, respectively, p=0.0001).Funding: AB Pork, ON Pork, AB Livestock Industry Development Fund, ACAAF, Ajinomoto.