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Studio Della Morfologia E Funzione Delle Gonadi Del Mollusco Haliotis Tuberculata Al Fine Di Ottimizzare L’Attività Riproduttiva in Ambiente Controllato

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Studio Della Morfologia E Funzione Delle Gonadi Del Mollusco Haliotis Tuberculata Al Fine Di Ottimizzare L’Attività Riproduttiva in Ambiente Controllato UNIVERSITÀ DEGLI STUDI DI MESSINA Dipartimento di Scienze Veterinarie DOTTORATO DI RICERCA IN SCIENZE VETERINARIE SANITÀ PUBBLICA VETERINARIA E SICUREZZA ALIMENTARE XXXII CICLO Settore Scientifico Disciplinare VET/03 Studio della morfologia e funzione delle gonadi del mollusco Haliotis tuberculata al fine di ottimizzare l’attività riproduttiva in ambiente controllato ______________________________________________________________ Candidato: Dott. Salvatore Cantarella Coordinatore: Ch.ma Prof.ssa Adriana Ferlazzo Tutor: Ch.mo Prof. Giovanni Lanteri ESAME FINALE 2019 2 SOMMARIO ABSTRACT ................................................................................................................................................................... 4 1 INTRODUZIONE .................................................................................................................................................. 5 1.1 LA SPECIE: HALIOTIS TUBERCULATA , LINNAEUS 1758............................................................................................... 7 1.2 SISTEMATICA .................................................................................................................................................. 9 1.3 MORFOLOGIA ...............................................................................................................................................10 1.3.1 Conchiglia .............................................................................................................................................10 1.3.2 Mantello ...............................................................................................................................................12 1.3.3 Piede .....................................................................................................................................................13 1.3.4 Capo .....................................................................................................................................................14 1.4 ORGANI INTERNI ............................................................................................................................................15 1.4.1 Apparato Respiratorio ...........................................................................................................................15 1.4.2 Apparato Circolatorio ............................................................................................................................18 1.4.3 Apparato digerente ...............................................................................................................................20 1.4.4 Sistema nervoso ed organi sensoriali .....................................................................................................23 1.4.5 Apparato riproduttivo ed escretore ........................................................................................................25 1.5 HABITAT E PARAMETRI FISICI .............................................................................................................................31 1.6 ALIMENTAZIONE ............................................................................................................................................32 1.7 DISTRIBUZIONE ..............................................................................................................................................34 1.8 IL GENERE HALIOTIS NEL MEDITERRANEO ..............................................................................................................35 1.9 PATOLOGIE ...................................................................................................................................................38 1.9.1 Patologie di Haliotis tuberculata ............................................................................................................41 2 SCOPO DELLA TESI .............................................................................................................................................43 3 MATERIALI E METODI ........................................................................................................................................44 3.1 PROVE DI ALIMENTAZIONE ................................................................................................................................48 3.2 CRESCITA IN AMBIENTE CONTROLLATO .................................................................................................................50 3.3 MATURITÀ SESSUALE INDOTTA ...........................................................................................................................52 3.4 PROVE DI RIPRODUZIONE CONTROLLATA ...............................................................................................................54 3.5 PATOLOGIE ...................................................................................................................................................60 3.5.1 Esame istopatologico.............................................................................................................................60 3.5.2 Microscopia Elettronica a Scansione (SEM) ............................................................................................61 3.5.3 Estrazione DNA......................................................................................................................................62 3.5.4 Polymerase Chain Reaction (PCR)...........................................................................................................63 4 RISULTATI E DISCUSSIONI ..................................................................................................................................64 4.1 ALIMENTAZIONE ............................................................................................................................................64 4.2 CRESCITA .....................................................................................................................................................67 4.3 MATURITÀ SESSUALE .......................................................................................................................................72 4.4 OSSERVAZIONI GONADI IN PAUSA RIPRODUTTIVA ....................................................................................................73 4.5 OSSERVAZIONE GONADI INIZIO GAMETOGENESI ......................................................................................................75 4.6 OSSERVAZIONE GONADI IN FASE MATURA .............................................................................................................77 4.7 RIPRODUZIONE CONTROLLATA ...........................................................................................................................80 4.8 PATOLOGIE ...................................................................................................................................................82 4.8.1 Esame istopatologico.............................................................................................................................82 4.8.2 Microscopia Elettronica a Scansione (SEM) ............................................................................................84 4.8.3 Polymerase Chain Reaction (PCR)...........................................................................................................84 5 CONCLUSIONI ....................................................................................................................................................86 6 BIBLIOGRAFIA ...................................................................................................................................................88 3 Abstract L’abalone mediterraneo Haliotis tuberculata oggi rappresenta un’importante risorsa naturale del nostro mare nonché una specie innovativa di grande interesse per il settore dell’acquacoltura. Si tratta di un mollusco gasteropode di cui attualmente non esistono impianti produttivi in Italia a causa di alcune lacune rilevate in determinate fasi di vita di questi animali. A tal proposito il principale obiettivo della tesi è stato quello di approfondire le conoscenze inerenti l’attività riproduttiva di H. tuberculata ed al contempo aggiungere informazioni su alimentazione, crescita e patologie. Sono stati campionati 100 esemplari provenienti da due siti collocati lungo la costa Jonica siciliana e su questi sono stati condotti studi riguardanti la biologia riproduttiva, alimentazione e crescita e patologie, concentrando l’attenzione sui parassiti riscontrati. È stato confermato che l’abalone mediterraneo può essere indotto alla maturazione delle gonadi ed all’emissione sincrona dei gameti secondo specifiche metodiche testate. È stata validata una metodica secondo osservazione morfo- cromatica per la valutazione delle singole fasi del ciclo sessuale. Le prove di alimentazione hanno mostrato una crescita rilevante soprattutto negli esemplari più giovani i quali hanno elevata velocità di accrescimento. Uno dei principali fattori limitanti l’allevamento sono le patologie, a tal fine è stata rivolta attenzione anche allo studio dei patogeni di questi animali. È stata riscontrata trematodosi del piede, documentata da esame istologico dal quale si evidenziavano numerosi cisti di metacercarie di trematodi digenei. Inoltre è stata rilevata coccidiosi associata alla presenza di protozoi nell’apparato gastroenterico. Riguardo i parassiti trematodi sono in corso indagini
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