ROLE OF DIETARY LIPIDS ON FETAL TISSUE FATTY-ACID COMPOSITION AND FETAL SURVIVAL IN SWINE AT 42 DAYS OF GESTATION

Eighty-six crossbred (Duroc x Yorkshire) gilts were used in two trials to assess the effect of supplemental dietary fats during early gestat ion on fetal survival, fetal development, and fatty acid (FA) composit ion in gilt plasma and fetal head and body at d 37 to 45 after breedin g. Three diets contained 4% (wt/wt) added fat either as coconut, soybe an (SO), or menhaden oils (MO). A fourth diet containing corn starch a pproximately isoenergetic to the quantity of the oils was used as a co ntrol. Across both trials, fetal survival percentage did not differ (P >.10) according to treatment, but in Trial 2 fetal survival was highe r (P <.06) for gilts fed the MO diet than for gilts fed the control di et. The FA composition of plasma of gilts at slaughter and the concept us tissues were similar; both were influenced by the FA composition of the diets. The ratio of n-3:n-6 FA was higher in conceptus tissue tha n in maternal plasma and the ratio was higher (P <.05) for the MO diet than for, the other diets. Subsequently, a total of 46 multiparous fe males were used in three trials to further evaluate the effects of MO on percentage of fetal survival relative to the corn starch control di et; the results demonstrated no differences (P >.10) in percentage of fetal survival due to the addition of MO. The high percentage of fetal survival observed in gilts on all the treatments and the unequal ovul ation rate in sows on different oil diets precluded definitive conclus ions regarding the effects of supplemental oil on fetal survival. Furt her research is necessary to determine whether an altered dietary FA c omposition, and the resultant altered FA composition of fetal tissues, contributes to improved fetal survival; however, SO, a supplier of th e 18-carbon omega-3 FA alpha-linolenic acid, did not provide the same FA composition in plasma and conceptus tissue that MO, a supplier of p reformed long-chain omega-3 FA (20:5n-3 and 22:6n-3), provided.