en Biotechnology Biotechnology پژوهشي Orginal research papers Ensiling as one of the best methods for utilization of tuna wastes was investigated. docosahexaenoic acid [DHA C22:6(n-3)]- rich products were obtained from the wastes (viscera and dark meat) of four tuna species, namely longtail, skipjack, yellowfin and kawakawa by a procedure involving ensiling in organic acids followed by neutralization. Identification of fatty acids in the samples was performed by comparison with chromatograms of fatty acids standard.<br> Total lipid content of silages varied from 10.41% in skipjack dark meat silage to 22.01% in kawakawa viscera silage, but all lipids contained high percentages of DHA and EPA [eicosapanteoneic acid C20:5(n-3)]. The highest DHA ratio (15% of total lipids) was found in the lipid of skipjack viscera silage and the highest ratio of EPA (11% of total lipids) belonged to the lipids of kawakawa dark meat silage.<br> ANOVA test results indicated that DHA ratio was significantly high before silage preparation and linolenic acid [C18:3(n-3)] content significantly differed between the species (p<0.05). Silage, PUFA, Tuna wastes, DHA, EPA, Persian Gulf 119 128 http://jifro.ir/browse.php?a_code=A-10-1466-1&slc_lang=en&sid=1 S. Tamadoni Jahromi stamadoni@yahoo.com 100319475328460024280 100319475328460024280 Yes A. Ghoroghi 100319475328460024281 100319475328460024281 No K. Rouhani 100319475328460024282 100319475328460024282 No K. Ejlali 100319475328460024283 100319475328460024283 No