100 DIET AND FATTY ACID COMPOSITION OF BOVINE PLASMA, GRANULOSA CELLS, AND CUMULUS - OOCYTE COMPLEXES

Abstract

The effects of altering dietary carbohydrates and lipids to oocyte donors during superovulation and ovum pickup (OPU) on in vitro embryo production was reported previously (Adamiak et al. 2004 Reprod. Dev. Fert. 16, 193–194). Here we report the effects of these dietary treatments on the fatty acid (FA) composition of plasma, granulosa cells (GCs), and cumulus–oocyte complexes (COCs) from the 32 heifers used in that study. Blood samples were collected by jugular venipuncture. COCs and GCs were harvested from each heifer by OPU as described previously but were pooled between pairs of heifers within treatment to provide adequate material for FA analysis. Both GCs and COCs were washed twice in PBS supplemented with 0.3% (w/v) BSA (FA-free) before being transferred into 2 : 1 (v/v) chloroform : methanol solution for FA extraction. FA composition was determined using gas chromatography as described previously (Reis et al. 2002, Theriogenology 57, 507). Data were analyzed by ANOVA. Total plasma FA content averaged 1.12 μg/mL and was unaffected by body condition score (BCS). Low BCS heifers had more saturated (54.0 ± 1.76 vs. 49.2 ± 1.74%) and monounsaturated (22.4 ± 1.08 vs. 18.2 ± 0.69%) FA, but less polyunsaturated FA (PUFA) (23.7 ± 1.75 vs. 32.8 ± 2.21%) in plasma than moderate BCS heifers (P < 0.01). Animals fed high relative to low fiber diets had greater plasma FA (1.3 ± 0.15 vs. 1.0 ± 0.12 μg/mL) and PUFA (31.2 ± 2.56 vs. 25.3 ± 2.19%), but less monounsaturated FA (18.8 ± 1.04 vs. 21.5 ± 1.09%) (P < 0.01). Dietary protected lipid (Ca soaps of FA) increased plasma FA (1.6 ± 0.07 vs. 0.6 ± 0.04 μg/mL) and PUFA (30.0 ± 1.92 vs. 26.4 ± 3.03%) (P < 0.05), but reduced plasma saturated FA (48.9 ± 1.12 vs. 54.2 ± 2.14%; P < 0.01) in the animals fed high compared to low fiber diets, respectively. In contrast to their effects in plasma, BCS and diet had little effect on FA composition of GCs and COCs. Although low BCS and dietary lipids both increased FA in COCs (78.3 ± 2.01 vs. 69.2 ± 2.80, P < 0.01; and 77.1 ± 2.96 vs. 70.5 ± 2.26 ng/COC; P < 0.05, respectively), neither factor significantly altered the FA composition of COCs. Across treatments, the FA composition of GCs and COCs differed markedly from that of plasma (Table 1), confirming the presence of a selective uptake mechanism in the follicle that can moderate dietary induced fluctuations in FA supply from peripheral circulation. Table 1. Concentrations of fatty acids in plasma, GCs, and COCs expressed as mean percentages (w/w) of total fatty acids This work was supported by Defra and The Perry Foundation.