Concentrations of amino acids in plasma from 45- to 47-week gestation mares and foetuses (Equus caballus).

This research investigates the concentration of amino acids in the blood of pregnant horses nearing birth and their foetuses, finding differences that suggest the horses’ placentas actively transport and concentrate these essential compounds into the foetal bloodstream similar to other species.

Study Overview

• The study focused on quantifying the concentration of amino acids in the blood plasma of mares and their foetuses close to the end of the gestation period (at 45 to 47 weeks).
• The investigation also aimed to comprehend the mechanisms through which the equine placenta delivers these crucial compounds to the developing foetus.

Foetal and Maternal Amino Acid Concentrations

• The research found significant differences in plasma concentrations of 20 of the 24 amino acids studied between the mother horses and their foetuses.
• In the case of 16 out of these 24 amino acids, the concentrations were higher in the foetal blood compared to the mare’s blood.
• However, for 4 of the 24 amino acids studied, the concentrations were lower in the foetal blood than in the mare’s blood.

Implication of Amino Acid Concentrations

• The higher foetal concentrations of certain amino acids are in line with what is observed in several other species.
• This suggests that similar to these other species, the horse placenta actively transports and concentrates specific amino acids into the umbilical circulation.

Comparison of Umbilical and Maternal Arteries and Veins

• The study found that 9 of the 24 amino acids had significantly lower concentrations in the blood plasma from the umbilical artery compared to that from the umbilical vein, indicating the fetus’ role in metabolizing these nutrients.
• However, there were no significant differences between the concentrations of amino acids in the blood from the mother’s artery and her vein.

Conclusion

• The study suggests that the foetus extracts amino acids from its umbilical circulation for metabolism – a process referred to as catabolism -or for protein synthesis.
• This is consistent with the behavior observed in foetuses of other species.