PAPER A COMPARATIVE STUDY ON FATTY ACID CONTENT OF MAIN ORGANS AND LIPID CLASSES OF LAND SNAILS ASSYRIELLA ESCHERIANA AND ASSYRIELLA GUTTATA DISTRIBUTED IN SOUTHEASTERN ANATOLIA . I. EKIN Sirnak University, Engineering Faculty, Department of Energy Systems Engineering, Sirnak, Turkey [email protected] ABSTRACT In the present work, main organs (digestive gland, cephalopedal, gonad and mantle) and lipid classes (total, neutral and phospholipid) of land snails Assyriella escheriana and Assyriella gutta- ta from southeastern Anatolia were examined for their fatty acids. The major components detect- ed in both of the species were C16:0, C18:0, C18:1ω9, C18:2ω6, C18:3ω3, C20:2ω6 and C20:4ω6. C18:2ω6 was identified as the primary fatty acid ranging from17.07% to 28.12% in A. guttata and 18.02% to 27.43% in A. escheriana. The proportions of C20:4ω6 modified to form prostaglandins that are directly involved in regulation of reproduction, ranged from10.01% to 20.30% in A. es- cheriana and 11.05 % to 16.58% in A. guttata. Taking into consideration that ΣPUFA levels were always higher than ΣSFA and ΣMUFA levels in all treatments of both species. This was an expect- ed finding for the snails collected during the breeding season because PUFA plays an important role as precursors for signal-transduction involved in the regulation of mating and reproduction. A significant amount of C20:2ω6 was concentrated in the cephalopedal of A. guttata (13.42%) and A. escheriana (14.93%). Probably, cephalopedal serves as a storage organ of this component. Con- sequently, the findings revealed that the snail’s fatty acid profiles were qualitatively similar, but quantitatively there were some differences. Most important of all, tissues of the snails were good source of essential fatty acids (C18:2ω6 and C18:3ω3) and PUFA, particularly omega 6 fatty acids. - Keywords: Fatty acids, Assyriella escheriana, Assyriella guttata, organs, lipid classes - Ital. J. Food Sci., vol. 27 - 2015 1 INTRODUCTION 40° 68’) at an altitude of 985 m and fifteen adult endemic Assyriella guttata species were collect- Assyriella escheriana and Assyriella gutta- ed from stony and rocky region of Diyarbakır ta (endemic to southeastern Turkey and North city walls (N 37° 55.2’ / E 40° 13.8’) at an alti- Iraq) species are common in moist and calcifer- tude 675 m. Both species were collected in April ous habitats of southeastern Turkey. Although 2012. Similar size (length: 4 ± 0.60 cm, wet flesh they are not eaten and commercially not export- weight: 13 ± 0.50 g) snail species were sampled ed, they are big enough and fleshy as much as for lipid analyses. The snails’ shells were re- edible relatives Helix lucorum, Eobania vermicu- moved and divided into seven groups (digestive lata dwelling in the same region. The fatty acid gland, cephalopedal, gonad, mantle, total lipid, distribution of a large number of commercial- neutral lipid and phospholipid) and their organs ly important marine and freshwater molluscs were dissected out. Then, tissues of each exper- have been reported and reviewed in varying de- imental set were conditioned in polyethylene grees of details (ACKMAN, 2000; KARAKOLTSID- bags and kept at -80°C until chemical analysis. IS et al., 1995). Lipids from marine, freshwater and edible land molluscs are more extensive- Extraction of fatty acids and GC analysis ly studied (ÖZOĞUL et al., 2005; MILINSK et al., 2006; MILETIC et al., 1991; RAKSHIT et al., 1997; Digestive gland, gonad, mantle, cephalopedal EKİN and BAŞHAN, 2010; EKİN et al., 2012, 2014) and whole body samples were homogenized in than those from nonedible terrestrial members. chloroform/ methanol (2:1, v/v) solution in order Nevertheless, nonedible land snails deserve spe- to extract total body lipids (BLIGH and DYER, cial attention from the point of their evolution- 1959). Organ’s lipid, total lipid, phospholipid and al relationship, roles in food chain, nutritional neutral lipid fractions were obtained according value, taxonomic and possible benefits in cos- to the method of STANLEY-SAMUELSON and metic, medicine and biochemistry. Nutritional, DADD, 1983. food chain and taxonomic studies are important Fatty acids methyl esters (FAMEs) were pro- in understanding interrelationship in marine, vided by capillary gas chromatography (GC) us- freshwater and terrestrial environment, how- ing Hewlett Packard (Wilmington, DE) gas chro- ever for the southeastern Anatolia; quite little matograph (model 6890), a DB-23 capillary col- data were available in the literature on edible umn (60 m × 0.25 mm i.d. × 0.250 μm film thick- and nonedible land snails. ness and Bonded 50% cyanopropyl) (J & W Sci- A. escheriana and A. guttata species whose entific, Folsom, CA), a flame ionization detec- edible relatives including Helix aspersa, H. as- tor, and Hewlett-Packard ChemStation software. emnis, H. cincta and H. lucorum, Theba pisana, The injection port and the detector temperatures Eobania vermiculata and Cantareus apertus, liv- were 270°C and 280°C, respectively. The split ra- ing in Turkey (YILDIRIM, 2004), can deserve more tio was 1:20. The flow rates of compressed air detailed studies. Many snail farms are being and hydrogen were 300 ml/min, 30 ml/min, established in some countries in order to pro- respectively. Carrier gas was helium (2.8 ml/ duce good quality snails for consumption and min). The oven temperature was programmed export. So, it seemed useful to make a compar- at a rate of 6.5°C/min from 130°C (1 min hold) ative study of similarity and differences in bio- to 170°C, then increased at a rate of 2.75°C/ chemical and nutritional composition of edible min to a 215°C, then again increased at a rate and nonedible snail species. of 40°C/min to 230°C, was held for 12 minutes. A comparative biochemical study on fatty acid Each tissue fatty acids percentages and spectra composition of snails belonging to same classes of FAMEs are obtained by HP 3365 ChemSta- but living in different habitats is hoped to pro- tion computer program. FAMEs existence and vide an insight into the adaptive capabilities and retention times were determined by comparing influence of the environment on their fatty acid the spectra of authentic standards (Sigma-Al- distribution. This paper discusses the fatty acid drich Chemicals). Individual FAME was identi- distribution of main organs and lipid classes in fied by comparisons with the chromatographic two same genus gastropods from southeastern behaviors of authentic standards. Anatolia, as data which is hoped to be basic to further comparative biochemical, nutritional, Statistical analyses taxonomic and evolutionary studies. The results were expressed as mean values ± SD (Standard Deviation). All analytical deter- MATERIALS AND METHODS minations were performed in triplicate and the mean values were reported. The analyses were Sample collection and preparation performed using a commercial statistical pro- gram (SPSS 20). The percentages of fatty acid Fifteen adult A. escheriana species were col- were compared by ANOVA variance analysis with lected from a woodland near Tizyan (Elmabahçe) 5% significance level. TUKEY’s test was used for village, 20 km north of Mardin (N 37° 49’ / E cooperation of average values. 2 Ital. J. Food Sci., vol. 27 - 2015 RESULTS (10.16%) and C18:3ω3 (8.42%) were identi- fied in the total lipid; C18:0 (11.21%), C18:1ω9 In both snails, C16:0, C18:0, C18:1ω9, (13.33%) and C20:2ω6 (11.79%) were in the C18:2ω6, C18:3ω3, C20:2ω6 and C20:4ω6 were neutral lipid; C18:2ω6 (27.43%) and C20:4ω6 presented as predominant fatty acids. Of the de- (20.30%) were in the phospholipid (Table 1). In tected fatty acids, amount of C18:2ω6 was the A. guttata, highest level of C16:0 (9.61%) and highest in all analyses from both A. escheriana C20:4ω6 (16.58%) were presented in the total and A. guttata (Tables 1 and 2). lipid; C18:0 (13.01%), C20:2ω6 (10.99%) and Compared to the fatty acids of the species’ C18:1ω9 (16.03%) were in the neutral lipid; organs, in A. escheriana, highest level of C16:0 C18:2ω6 (22.34%) and C18:3ω3 (10.70%) were (11.81%) and C18:1ω9 (20.56%) were present- in the phospholipid (Table 2). ed in the gonad; C18:0 (15.18%) and C20:2ω6 In all treatments, results showed that concen- (14.93%) were in the cephalopedal; C18:2ω6 tration of ω6 (omega 6) always higher than con- (26.67%) and C18:3ω3 (7.36%) were in the di- centration of ω3 (omega 3) family fatty acids. In gestive gland and C20:4ω6 (17.86%) was in the A. escheriana, the ratio of Σω6 / Σω3 was 4.86, mantle (Table 1). In A. guttata highest level of 6.71, 5.44 and 7.66 in the digestive gland, ceph- C16:0 (9.72%), C18:1ω9 (19.65%) and C18:3ω3 alopedal, gonad and mantle, respectively (Table (4.76%) were found in the gonad; C18:0 (15.21%) 1). In A. guttata it was 5.13, 8.49, 5.29 and 4.84 and C20:4ω6 (15.68%) were in the mantle; in the digestive gland, cephalopedal, gonad and C18:2ω6 (28.12%) was in the digestive gland and mantle, respectively (Table 2). Additionally, Σω6 C20:2ω6 (13.42%) was in the cephalopedal (Ta- / Σω3 ratio were 5.19 in the total lipid, 4.86 in ble 2). On the other hand, the fatty acids from the neutral lipid and 6.59 in the phospholipid of lipid classes of the species showed some differ- A. escheriana (Table 1). This ratio was observed ences, in A. escheriana, highest level of C16:0 4.00 in the total lipid, 3.91 in the neutral lipid Table 1 - Fatty acid profile of main organs total lipid and lipid classes from Assyriella escheriana.