Abstrak 
Formasi Mutiara Kerang Air Tawar Anodonta Woodiana Yang Menerima Material Iritan
Cyska Lumenta
Unpad
Indonesia
Unpad
anesthetics, Anodonta woodiana, crystal tablets, irritant materials, Pearl
Penelitian untuk mempelajari formasi mutiara pada kerang air tawar Anodonta woodiana yang menerima material iritan telah dilaksanakan di Balai Budidaya Air Tawar Tatelu di Kecamatan Dimembe, Kabupaten Minahasa Utara, Provinsi Sulawesi Utara. Penelitian pendahuluan yang dirancang secara eksperimental dengan rancangan acak lengkap berpola faktorial bertujuan untuk menentukan bahan dan dosis anestesi terhadap prakondisi kerang untuk implantasi. Bahan anestesi yang digunakan adalah minyak menthol, minyak cengkeh, minyak pala, dan minyak sereh dengan konsentrasi masing-masing 1,5 ml/L, 2,5 ml/L, dan 3 ml/L. Penelitian utama yang juga dirancang secara eksperimental bertujuan untuk menentukan material dan diameter iritan yang tepat dalam formasi mutiara pada kerang ini. Material iritan yang dicobakan adalah pasir kerikil, pecahan gelas dan manik-manik, masing-masing berdiameter 3 mm dan 6 mm. Hasil penelitian menunjukkan adanya pengaruh interaksi antara bahan dan dosis anestesi terhadap kondisi rileks kerang untuk memudahkan penyisipan iritan pada tubuhnya. Penggunaan bahan anestesi berupa minyak pala dengan dosis 2,5 ml/L lebih efektif untuk prakondisi kerang (respons, waktu rileksasi, waktu pulih, dan mortalitas) dibandingkan dengan bahan anestesi minyak cengkeh, minyak menthol, dan minyak sereh. Selama pemeliharaan pasca pemberian iritan, kerang tetap mampu hidup normal dengan laju sintasan yang bervariasi antara 89,8% dan 96,2%, demikian pula pertambahan bobot tubuhnya (1,31-1,76% per hari) relatif sama dengan kerang yang tanpa implantasi iritan. Selain itu, material iritan tidak menyebabkan peradangan pada jaringan mantel kerang, sebagaimana ditandai dengan absennya sel-sel basofil dan eosinofil. Meskipun material dan diameter yang berbeda, tidak signifikan menentukan perbedaan keberhasilan implantasi, tapi percobaan ini menunjukkan lebih dari 50% (59,16 – 84,99%) kerang yang diimplantasi berhasil membentuk lapisan mutiara. Pertambahan bobot iritan karena terlapisi mutiara dipengaruhi interaksi antara material dan diameter iritan, sementara pertambahan tertinggi terjadi pada material pasir kerikil berdiameter 3 mm (0,039%) dan berdiameter 6 mm (0,137%). Selain kalsium karbonat sebagai wujud biomineralisasi mutiara, komposisi mineral lapisan mutiara pada iritan pasir kerikil ditandai aluminium oksida yang dominan dibandingkan lapisan mutiara lainnya. Faktor butiran pasir kerikil dalam implantasi kerang menghasilkan laju pertambahan lapisan mutiara tertinggi, sebesar 0,57% per hari dengan ketebalan tablet kristal aragonite/vaterite mencapai 0,36-0,56 ìm.
The research on pearl formation in the freshwater mussel Anodonta woodiana implanted by irritant materials was conducted at the Center of Freshwater Culture, Dimembe District, North Minahasa Regency of North Sulawesi Province. The preliminary study which was conducted by using randomized factorial design experiment was aimed to determine the suitable anesthetic types and concentrations for preconditioning the mussels for implantation. Test materials used is material with four type of oil and three concentrations, which are menthol oil, clove oil, nutmeg oil and citronella oil with each concentration of 1.5 ml/L, 2.5 ml/L, and 3 ml/L. While the main experiment was conducted to determine the suitable irritant materials and their sizes for pearl formation in the mussels. Materials irritant tested is grain of pebbles, broken glass, and beads with diameter of each 3 mm and 6 mm. The result showed that there was an effect on interaction between the type and the concentration of the anesthetics to the ‘relaxed condition’ of the mussels in order to ease the implantation process. It was found that the use of nutmeg oil 2.5 ml/L is more effective for applying at the preconditioned stage of the mussels (based on response, relaxation time, recovery time, and mortality rate) compared to clove oil, menthol oil and citronella oil. After the implantation, the survival rate of the mussels was between 89.8% and 96.2%, and the increasing body weight was from 1.31 to 1.76% per day. This result was relatively similar to the mussels without any implantation treatment. Implant materials were not found to cause any defect on mantle tissue of the mussels, which was characterized by the absence of basophillic and eosinophillic cells. The difference in types and sizes of the irritant materials did not give any significant result in the success of the implantation. But the result showed tha more than 50% (between 59.16 and 84.99%) of the mussels used in the experiment had succeeded to form a pearl. The increasing size of the irritants due to the coating of pearl layers is affected by the interaction between types and diameter of the irritants. The highest increase in size was found in pebbles materials which had reached the diameter of 3 mm (0.039%) and 6 mm (0.137%). Alumunium oxide was the dominant mineral compound composing the pearl layers on the pebbles compared to other pearls. ‘Pebbles factor’ as the irritant is found to produce the highest increase of pearl layers; 0.57% per day with the thickness of aragonite/vaterite crystals can reach up to 0.36-0.56 ìm.
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