Untitled - CNR

Fishery and Sea Resourcesthe polychaete Sabella spallanzanii underlaboratory conditions as well as inan aquaculture farm in different feedingconditions, in order to produce biomasssuitable for both the extraction of antimicrobialcompounds and the fodder production;- evaluation of the growth capability ofmacroalgae in laboratory, greenhouse(Figures 2a, 2b) as well as in an aquaculturefarm (Figure 2c) with differentconcentrations of nitrogen salts, in orderto produce biomass suitable for both theextraction of antimicrobial compoundsand the fodder production. The followingalgal species were examined: Cystoseirabarbata, Chaetomorpha linum,Gracilaria bursa-pastoris, G. dura, G.gracilis, Hypnea cornuta, Gracilariopsislongissima and Grateloupia turuturu;- biochemical analyses of the selected marineinvertebrates and macroalgae (i.e.proteo-lipid content, content in ω3, comparisonof monounsaturated and polyunsaturatedfatty acids, determination ofthe ω3/ω6 fatty acid ratio) in order toevaluate their nutritional value by gaschromatography;- research of natural compounds showingantimicrobial activity was performed onthe mucus produced by the polychaetesS. spallanzanii and Branchiomma luctuosum,nematocyst extracts of the cnidariansParazoanthus axinellae, Condylactisauriantiaca and Actinia aequina as wellas on the lipidic extracts of macroalgae.Scanning electron microscopy (SEM)was also used to evaluate the damageon bacteria treated with nematocyst extracts.The effectors responsible forthe antimicrobial activities were characterizedby gas-chromatography, gelchromatographyand high pressure liquidchromatography.3 ResultsConcerning the growth capability of polychaetesreared both in laboratory and inaquaculture farm, we obtained a conspicuousbiomass (Figure 3a, b, c ). Moreover,the selected macroalgal species showedhigh growth rates both in laboratory and ingreenhouse culture, displaying also a goodcapacity in dissolved nitrogen uptake especiallyin the ammoniacal form.As regards the biochemical analysis (Table1), polychaetes exerted an interestingproteo-lipidic profile. In particular,the polychaete S. spallanzanii is composedof proteins for 26% of the total dryweight, of lipids for 7% (0.32% cholesterol,0.84% phospholipids, 0.40% triglyceridesand 5.49% other) of water for about79%. Of particular interest is also the presenceof long-chain polyunsaturated fattyacids of the ω3 series.Saturated fatty acids (SAFAs) were themost abundant fatty acid class in all theexamined macroalgae and the palmiticacid methyl ester (16:0) was the prevalentSAFA followed by myristic acid methylester. Monounsaturated (MUFAs) andpolyunsaturated fatty acids (PUFAs) usuallyshowed the same proportion. Asregards MUFAs, oleic acid methyl ester(18:1 ω9) prevailed. The ω3/ω6 fattyacids ratio, which represents an interestingnutritional indicator, was > 1 in severalspecies. Concerning the antimicrobialactivity, the mucus of S. spallanzanii (Figure3d, e, f) showed a lysozyme-like activity.The maximum diameter of the lysisobserved was 9.6±0.02 mm correspondingto 1.31 mg/ml of lysozyme of chicken eggwhite. A lysozyme-like activity was alsoevidenced in B. luctuosum with the maximumdiameter of lysis of 5.5±0.50 mmcorresponding to 0.75 mg/ml of lysozyme2048