179 INTRAFOLLICULAR CONCENTRATION OF FATTY ACIDS IN GOAT ACCORDING TO FOLLICLE DIAMETER AND AGE OF DONOR

Abstract

Oocytes from adult goats have better competence to develop up to blastocyst stage than those from prepubertal females. Previous results in our laboratory showed that oocyte developmental competence in prepubertal goats is positively related to follicle diameter, as oocytes from follicles larger than 3 mm have the same competence as adult goat ones, demonstrating that follicular environment affects oocyte competence for embryo development. Other studies concluded that fatty acids (FA) in follicular fluid (FF) play an important role in oocyte and embryo development. The aim of this study was to analyse FF composition regarding FA percentage comparing samples from adult (3 years old, forage diet) or prepubertal (1 month suckling) Murciano-Granadina goats. FF samples were recovered from follicles larger and smaller than 3 mm by laparoscopy (adult) or aspiration of ovaries collected at slaughterhouse (prepubertal). For the FA analysis, the Sukhija and Palmquist protocol was used with some modifications. Briefly, 200 μL of FF sample was vortexed for 60 s with 250 μL of toluene and 1 mL of HCL (5%) and then warmed in water bath for 1 h at 70°C. Subsequently, 1.25 mL of K₂CO₃ (12%) and 500 μL of toluene was added, vortexed for 30 s, and centrifuged for 5 min (3000 rpm). Finally the supernatant was recovered and dried with Na₂SO₄. The extracted samples were maintained at –20°C until gas chromatographic analysis (123–2362, Agilent Technologies Inc., Santa Clara, CA). The results are shown in Table 1. The analysis of FA composition in FF showed significantly higher concentrations of C15:0 (pentadecanoic), C16:0 (palmitic), C17:0 (margaric), C18:0 (stearic), linolenic acid (ALA), and EPA (eicosapentanoic) in adult goats compared to prepubertal goats, and C17:0, C18:0 linoleic acid (LA), and ALA in larger follicles of prepubertal females, showing some coincidences in follicular environment that could explain previous studies. These results are in agreement with those of Matoba et al. (2014; Rep. Fertil. Dev. 26, 337) who showed that FF associated with more competent oocytes had a significantly higher concentration in ALA than FF from incompetent oocytes in cattle.

Table 1.  Concentration of FA (%) in FF in adult and prepubertal goats (top) and in FF of large and small follicles (bottom) from prepubertal goat ovaries (3 replicates)