Mid and term pregnancy IGF-I and nefa concentrations in Fetal fluids of queens: preliminary results

Insulin-like growth factor-I (IGF-I) and non-esterified fatty acids (NEFA) are involved in fetal growth and development. Whilst IGF-I has been considered as a possible indicator of potential growth, NEFA is recognized as a marker of fat mobilization, because of energy request [1]. A study on canine foetal fluids collected at term [1] reported the absence of significant differences in NEFA concentrations, but higher IGF-I in amniotic than allantoic fluids, and in large breeds than small and medium breeds in dog, providing the first evidence that amniotic IGF-I could be used as an indicator of potential growth in dogs. However, differently to the dog, the study of foetal fluids composition received little scientific interest in cats. Although a couple of studies [2,3], described the biochemical composition of feline foetal fluids at different time of pregnancy, the authors are not aware of studies about IGF-I and NEFA concentrations in feline foetal fluids. Therefore, this study aimed to report preliminary results about the IGF-I and NEFA concentrations in foetal fluids of cats at mid and term of pregnancy. The study was performed on 8 queens submitted to mid pregnancy ovariohysterectomy for unwanted pregnancy and on 3 queens submitted to Caesarean section because of dystocia occurred at term of pregnancy. Amniotic and allantoic fluids were separately collected from 37 mid pregnancy foetuses and from 10 term pregnancy, normally developed and viable foetuses, and immediately stored at -20° C until analysis for IGF-I and of NEFA concentrations by RIA. The results showed no significant differences in NEFA concentrations neither between the two foetal fluids at both mid and term pregnancy nor between the two times of sampling within each fluid. On the opposite, a significant (p<0.05) higher IGF-I concentration was found in amniotic and allantoic fluids at term in comparison to the same fluids collected at mid pregnancy, whilst no differences were found between the two fluids at both sampling times. These results suggest that, in cats, higher amniotic and allantoic fluid IGF-I concentrations at term could be related to the final growth of the foetus at term, and, likely to what reported for the dog, could be considered as an indicator of foetal potential growth.