ABSTRACT. The present review focuses on the effect of dietary intake of ω-3 (n-3) Polyunsaturated Fatty Acids (PUFA's) on the reproductive performance of sows and boars, as well as on the health status of sows and their piglets. PUFA's are divided into n-6 and n-3 series that are found in high levels in plant and fish oils, respectively. a-Linolenic acid, eicosapentaenoic acid and docosahexaenoic acid are the main PUFA's of the n-3 series. They antagonize n-6 PUFA's for incorporation into the cell membrane phospholipids and biosynthesis of eicosanoids of the respective n-series. n-3 PUFA's cannot be synthesized by pigs and their presence in high levels in vital organs and tissues emphasizes their importance and essentiality, especially during rapid tissue formation, i.e gestation and fetal/neonate development. n-3 PUFA's can cross the placenta into the fetal circulation, thus maternal dietary PUFA's intake during pregnancy influences the fatty acid composition of plasma and tissues of the developing fetus. Similarly, n-3 PUFA's concentrations in colostrum and milk are also increased in response to the maternal dietary n-3 PUFA's supplementation. PUFA's play a critical role in inflammatory and immune responses, since they are precursors of eicosanoids and they also mediate the production of several immunoregulators. In this direction, the potential immunological benefit of n-3 PUFA's dietary supplementation, in cases of infections involving gram negative bacteria or Mycoplasma hyopneumoniae in sows and piglets, remains a scientific topic of increasing interest. Research data also underline the beneficial effect of n-3 PUFA's maternal dietary intake on the reproductive performance of sows, especially as regards the litter size at birth and the mortality rate of piglets during lactation. n-3 PUFA's do not seem to affect the ovulation and/or the conception rates, however there is evidence of their biological role in enhancing early embryonic survival. Furthermore, they have a significant impact on brain and normal cognitive development, suggesting improved piglet vigour at birth, an advanced suckling behaviour and consequently a reduced pre-weaning mortality rate. Feeding boars with diets supplemented with n-3 PUFA's is also highly recommended to enhance semen characteristics. The importance of these fatty acids in relation to boar fertility has been illustrated by studies demonstrating a beneficial effect on sperm viability and motility, as well as on the proportion of spermatozoa with abnormal morphologies.     

Key words: n-3 polyunsaturated fatty acids, sows, boars, reproductive performance

Volume 58 (No. 3 p. 353-366) / 2007