Fatty acid signature of mature gonads of Arbacia dufresnii (Blainville, 1825) (Echinodermata: Echinoidea) at Bahía Nueva, Patagonia, Argentina.

ZARATE, E; DÍAZ DE VIVAR, M. E.; AVARO, M.; EPHERRA, L; SEWELL, M.

Bruselas

Conferencia; 14th International Echinoderm Conference.; 2012

The fatty acid (FA) signature in marine organisms is characteristic for every species and genus and can be used to understand food web interactions. Since echinoid gonads have a multifunctional role and reflect both nutritive and reproductive status, FA profile of gonads reflects the reproductive cycle, the energetic investment for this process and the changes in sexual maturation. Thus, the FA profile is a useful method for examining the biochemical changes in marine invertebrates linked to their reproductive cycle. Thirty individuals were collected monthly at Punta Cuevas (42°46´37´´ S, 64°54´51´´O) (Bahía Nueva, Chubut, Argentina) for two years (2009-2010). Gonads were dissected out and gonad index was calculated. Maturity stage was assessed by histological studies. issues of each individual were liophilized and submitted to transesterification to obtain fatty acids methyl esters (FAME), which were analyzed by GC-MS. FAMEs were identified by comparing their relative retention times and electron impact mass spectra with those of authentic standards. Results are shown for the individuals at the maturity stage (September 2009 and 2010) assessed from histological studies and gonad index values.The main FA were icosapentaenoic, palmitic, arachidonic, stearic and oleic acids, with little differences in abundance for both sexes. Greater differences appear when the rate Insaturated/Saturated acids are concerned, this being 1.8 for females and 3.2 for males. Previous studies have shown that neutral lipids account for more than 50% of total lipids for female gonads, while phospholipids are dominant in male gonads. Then, the FA profile could reflect triglicerides and membrane lipids composition for each sex.