Evaluation of Biochemical Composition of Amniotic and Allantoic Fluids at Different Stages of Pregnancy in Queens

Abstract

Fetal fluid contents have functions in protecting fetuses and are essential for fetal development and maturation. However, little is known about the exact physiological functions of fetal fluids in fetal development, as well as the changing composition throughout the gestational period in cats. In this study, the biochemical composition of amniotic (AMN) and allantoic (ALL) fluids was investigated, as well as in the maternal serum of pregnant queens. Eighteen queens were included in this study and assigned to six different groups, D20, D25, D30, D40, D45 and D60, according to the gestational stage of fetal development. A total of 44 amniotic and 37 allantoic samples were collected. Fetal fluids contained lesser concentrations of alanine aminotransferase, albumin, cholesterol, triglycerides, creatine kinase, amylase, total protein and globulin than maternal serum. Other variables, such as aspartate aminotransferase, gamma-glutamyl transferase, bilirubin and alkaline phosphatase, were in different concentrations at specific stages of gestation when compared to maternal serum. There were no differences between fetal fluids and maternal serum for lactate dehydrogenase, urea, lipase or glucose concentrations. There were greater concentrations of creatinine in amniotic fluid than in allantoic fluid or maternal serum. Based on the results of this study, fetal fluids do not accumulate as a result of the simple filtration of maternal blood, but rather, the fetus produces many of these components as a consequence of organ development and maturation.

Canine and feline foetal fluids: Volume, hormonal and biochemical characterization during pregnancy

“…ALT activity showed no significant change in the allantoic fluid of cats, similar to Bigliardi et al. ( 2022 ), but in the amniotic fluid decreased until days 40–50 and after that increased. AST activity increased in the feline allantoic fluid, especially after day 45 (Bigliardi et al., 2022 ), and similarly, in the current study, AST activity increased significantly in the allantoic fluid of cats.…”

“…The maximum activity of creatine kinase in the feline allantoic fluid was observed on days 50-60, probably indicating the muscular development of the fetus during the end of pregnancy. Maximum creatine kinase activity in the feline allantoic fluid was observed on days 50-60, probably related to the muscle growth of the fetus, whereas, in the amniotic fluid, its activity decreased during pregnancy despite consistently similar activities during the gestation period in other studies (Bigliardi et al, 2022;Fresno et al, 2012). Creatine kinase activity in dog ' s allantoic and amniotic fluids did not change during pregnancy, and no significant difference was observed between fluids.…”

“…( 2022 ), but in the amniotic fluid decreased until days 40–50 and after that increased. AST activity increased in the feline allantoic fluid, especially after day 45 (Bigliardi et al., 2022 ), and similarly, in the current study, AST activity increased significantly in the allantoic fluid of cats. In contrast, AST activity decreased in both canine foetal fluids and despite (Veronesi et al., 2018 ) in amniotic fluid was higher than allantoic.…”

“…The allantoic fluid is more similar to urine due to the function of the definite kidney in late pregnancy. Urine transfers to amniotic fluid regarding urachus duct occlusion and urethra formation (Bigliardi et al., 2022 ). This can explain the decrease of allantoic fluid volume and the increase of amniotic fluid at the end of gestation.…”

“…Previous studies on canine foetal fluids are limited to the investigation of the biochemical composition of foetal fluids at term (Veronesi et al., 2018 ) and other studies on some scattered factors of these fluids from embryonic vesicles delivered by emergency or elective caesarean section so our knowledge about the changes of biochemical components during pregnancy is rudimentary. The biochemical composition of feline foetal fluids during pregnancy has been investigated in two studies (Bigliardi et al., 2022 ; Fresno et al., 2012 ), and some differences were observed between the results of these studies. There is only one study (Wislocki, 1935 ) on feline foetal fluids volume; more investigations are needed in this field.…”