Effect of gestation dietary methionine/lysine ratio on placental angiogenesis and reproductive performance of sows1

Abstract

The current study aims to evaluate the effects of different gestation dietary Met/Lys (methionine, Met/lysine) ratios on the production performance of sows. Specifically, it measured the effect of Met on plasma urea and AA concentrations and placental vascular density of pregnant sows. A total of 325 multiparous sows (third parity, Large × White) were randomly allocated to five dietary treatments (n = 65) with five dietary Met/Lys ratios 0.27 (nutrient requirements of swine [NRC] 2012 level), 0.32, 0.37, 0.42, and 0.47). The litter size and weight at birth were measured and recorded. Blood samples were obtained on days 0, 40, 90, and 114 of gestation, and placenta samples were collected at parturition. The effects of different dietary Met/Lys ratios on the reproductive performance were evaluated based on the prolificacy of sows as either high (≥13 total piglets born) or low (<13 total piglets born). The results showed that dietary Met/Lys ratio had no significant effect on the reproductive performance of lower prolificacy sows (P > 0.05). However, for high-prolificacy sows, litter weight of born alive significantly increased in 0.37 Met/Lys ratios group compared with control group (P < 0.05). The gestation dietary Met/Lys ratio showed significant quadratic effects on the litter birth weight and percentage of piglets born with weight <0.9 kg (P < 0.05), and the Met/Lys ratios to achieve the best reproductive performance determined to be 0.37. Furthermore, plasma urea concentrations of sows also changed with Met/Lys ratios quadratically (P < 0.05). Increasing dietary Met/Lys ratios elevated the concentration of most plasma AA. Although the dietary Met/Lys ratio had no significant effect on the placental vascular density (P > 0.05), the gestation dietary Met/Lys ratio showed significant quadratic effects on the placental vascular density (P < 0.05). In addition, the birth weight of piglets of high-prolificacy sows was positively correlated with the placental vascular density (P < 0.01). Taken as a whole, the dietary Met/Lys ratio showed a quadratic curve relation with birth weight performance and placental angiogenesis performance, to which 0.37 ratio contributed to the best performance of high-prolificacy sows.

Effect of Sows Gestational Methionine/Lysine Ratio on Maternal and Placental Hydrogen Sulfide Production

“…In modern animal production, gestational restriction feeding is an effective and widely used practice to improve the reproductive performance of sows. Our previous study found that under the restriction feeding conditions, increasing the Met/Lys ratio from 0.27 to 0.37 can significantly increase the average pig birth weight and the litter weight in the pigs that are born alive [6]. However, when Met/Lys ratio was further increased to 0.47, the rate of piglets with a weight <0.9kg increased and the placental vascular density decreased significantly [6].…”

“…Our previous study found that under the restriction feeding conditions, increasing the Met/Lys ratio from 0.27 to 0.37 can significantly increase the average pig birth weight and the litter weight in the pigs that are born alive [6]. However, when Met/Lys ratio was further increased to 0.47, the rate of piglets with a weight <0.9kg increased and the placental vascular density decreased significantly [6]. In this study, the maternal plasma at E114 d and the placental H 2 S concentrations were consistent with the sows' reproductive performance.…”

“…The experimental design and the dietary formula were described previously [6]. In this study, multiparous sows (Large×White; third parity; n = 65) were randomly allocated into five groups and fed diets with standardized ileal digestible methionine/lysine (Met/Lys) ratios of 0.27 (nutrient requirements of swine (NRC); 2012 level), 0.32, 0.37, 0.42, and 0.47 respectively.…”

“…The sample collection of blood and placenta was described previously [6]. Twelve sows by group were selected for blood sampling, and eight sows of each group were selected for placenta sampling.…”

“…Functional amino acids are important for the development of the pig placenta [5]. In our previous work, we demonstrated that an appropriate increase in the methionine/lysine (Met/Lys) ratio in a sow's diet had a positive effect on the sow'splacental vascular density and on the birth weight of the piglets [6]. However, the underlying mechanism by which Met promotes placental angiogenesis and fetal development is unclear.…”