The aim of the study was to evaluate the effect of time of gestation on fatty acid transporter and receptor mRNA concentration in maternal and fetal bovine placenta. Placentas from 12 cows at different thirds of gestation (n = 4 per third) were sampled at slaughter to measure FATP-1, FATP-4, FABP-1 mRNA concentration in maternal (caruncles) and fetal (cotyledons) side. Once the placenta was removed, 1cm2 was dissected and, divided into caruncles and cotyledons, stored in sterile tubes, dropped into liquid nitrogen and kept at −80°C until rtPCR analysis. Extraction of RNA was performed with TRIzol. Fetal and maternal placenta cDNA was subjected to qPCR assays using EvaGreen as intercalating dye (KAPA FAST, Biosystems, Woburn). Quantitative PCR was performed in a Rotor Gene Q thermocycler (Qiagen). Relative mRNA concentration was calculated by ddCt method using β actin as housekeeping gene. Data were analyzed as a complete randomized design with a 3 × 2 factorial arrangement, using the mixed procedure (SAS 9.3) with repeated measurements on space. Time of gestation, size of the placenta and their interaction were fixed factors, whereas animal was a random factor. There was a time by treatment interaction (P < 0.01) on FATP-1 mRNA expression of due to a greater mRNA expression in cotyledons on the first third of gestation as compared with the concentration in caruncles (Table 1). On the second and third thirds of gestation, the mRNA concentration in cotyledons decreased, reaching a similar concentration to that observed in caruncles (Table 1). FATP-4 and FABP-1 mRNA concentration were not different (P > 0.1, Table 1). We conclude that FATP-1 would play an important role in fatty acid transport during early fetal development. Table 1. Relative mRNA concentration of FATP-1, FATP-4, FABP-1 mRNA in different thirds of gestation on maternal (caruncles-M) and fetal (cotyledons-F) side on bovine placenta

Item	M				F			SEM	P-value
1	2	3	1	2	3	Side	Third	Side × Third
FATP-1	0.63	0.30	0.94		2.14	1.26	0.92	0.29	0.01	0.15	0.07
FATP-4	1.85	0.90	1.94		1.94	0.99	0.78	0.78	0.55	0.42	0.53
FABP-1	3.07	2.01	2.62		3.29	4.09	3.77	1.42	0.35	0.99	0.80