LIPID-COMPOSITION OF SEMEN IN DIFFERENT FOWL BREEDERS

The lipid composition of spermatozoa and seminal plasma have been stud ied in different strains of chicken breeders and in turkey breeders fe d a standard commercial diet. The following strains have been consider ed: egg-type breeders (ISA and RIR), broiler breeders (COBB and ROSS) and NICHOLAS turkey breeders, Semen samples have been collected for li pid analysis during the first half (23-42 weeks) of the reproductive p eriod. The liver and testis tissues have been dissected from RIR, ROSS , COBB and NICHOLAS males at the end of the reproductive period and li pid composition determined. The total amount of lipid measured in sper matozoa was higher in turkey (952 mu g/10(9)) than in chicken breeders (522 mu g/10(9)). Total phospholipid, the main lipid component of spe rmatozoa, accounted for a lower proportion in turkey (59%) compared to chicken (66-69%) breeders. The relative content of free cholesterol w as 20% in spermatozoa of meat-type breeders (chicken and turkey) and 1 0% in chicken egg-type breeders. In sperm phospholipid, 18:0 was the m ajor saturated fatty acid in all the strains; 18:1n-9 and 20:1n-9 were the major monounsaturates in chicken and turkey strain respectively; 22:4n-6 was the major polyunsaturated fatty acid found in birds and it s relative content progressively decreases from ISA breeder (30%) to C OBB and ROSS breeders (22%) to NICHOLAS breeders (15%). Phospholipid c omposition of spermatozoa was similar in all the strains considered: p hosphatidylcholine was the main class (34%) followed by a slightly low er proportion of phosphatidylethanolamine; phosphatidylserine and card iolipin were present in higher proportion in chicken (21-29% and 4.5% respectively) compared to turkey breeders (12% and <1% respectively); the relative content of sphingomyelin was very similar in the differen t strains (11%). Seminal plasma lipid composition was measured in ISA, COBB and NICHOLAS strains, Phospholipid accounted for 46% and 40% of total lipid in seminal plasma of chicken and turkey breeders respectiv ely; free cholesterol showed the highest (49%) proportion in turkey an d the lowest (16%) in chicken breeders; the proportion of free fatty a cids was almost seven times higher (34%) in plasma phospholipid of ISA breeders compared to COBB and NICHOLAS breeders, According to the spe rm fatty acid phospholipid composition, turkey seminal plasma was enri ched in n-9 PUFAs (20:1 and 22:3) compared to chicken. Differences in fatty acid composition of the total phospholipid were found between li ver and testis tissue in all the strains studied. The relative content of 18:2n-6 was higher in the liver compared to the testis tissue (20% vs. 3%), 20:4n-6 was present in similar amount in both tissues (11% - 16%), 22:4n-6 was higher in the testis compared to the liver tissue ( 14% vs. 1%). It is suggested that the most important PUFA 22:4n-6 esse ntial for sperm production is synthesised within the testis tissue and not delivered already formed from the liver tissue.