Pengaruh Paparan Chlorine terhadap Stress Fisiologis dan Ekspresi Gen Hsp70 dan Hsp90 pada Abalon (Haliotis squamata)

Abstract

Abalon merupakan salah satu moluska bercangkang tunggal yang memiliki nilai ekonomis tinggi dan merupakan komoditas potensial dalam peningkatan devisa Negara. Namun permasalahannya adalah mudahnya abalone mengalami stress akibat perubahan berbagai faktor lingkungan seperti suhu, salinitas, bakteri Vibrio dan bahan desinfektan seperti chlorine. Penelitian ini dilakukan untuk mengetahui tingkat stress benih abalone terhadap paparan chlorine pada gen heat shock protein (HSP) dan mengetahui perubahan enzim-enzim  antioksidan seperti SOD,CAT,PO dan perubahan struktur histologi otot kaki abalone akibat paparan chlorine. Koleksi benih abalone dengan ukuran cangkang 3-4 cm dari unit hatchery abalone, BPIU2K Karangasem Bali. Uji paparan abalone pada akuarium kaca volume 100 L dengan konsentrasi chlorine 10 ppm. Pengambilan sample (hemolim, otot kaki, gonad) dilakukan pada waktu pengamatan (0,12,24,48 jam). Pengamatan meliputi uji  ekspresi gen heat shock protein (Hsp70 dan Hsp90), aktifitas enzim-enzim antioksidan dan histology pada otot kaki. Hasil penelitian menunjukkan bahwa Hsp70 terekspresi paling tinggi pada hemolim abalone yaitu sebesar 350 kali lipat pada paparan jam ke 12 dibandingkan kontrol (P<0.05). Sedangkan, Hsp90 pada waktu yang sama menunjukkan tingkat stress abalone paling tinggi pada otot kaki dengan tingkat ekspresi sebesar 7 kali lipat jika dibandingkan kontrol (P<0.05).  Gen heat shock protein diekspresikan cukup tinggi pada uji paparan chlorine, namun demikian  Hsp70 menunjukkan tingkat ekspresi yang lebih tinggi jika dibanding dengan Hsp90. Hsp70 lebih sensitif sebagai marka stress abalone akibat paparan chlorine. Perubahan struktur histologi menunjukkan cemaran chlorine dapat meningkatkan ukuran diameter hemolim sinus dan kerusakan pada lapisan epithel otot kaki abalone.

Abalone is one of the single-shelled mollusks which has high economic value and is a commodity in increasing the country's foreign exchange. However, the problem is that it is easy for abalone to experience stress due to the influence of various environmental factors such as temperature, salinity, Vibrio bacteria and disinfectants such as chlorine. The study was conducted to determine the stress level of abalone seeds produced by hatcheries against residual chlorine. The aim of the study were to see the stress level based on the heat shock protein (HSP) gene and to see changes in antioxidant enzymes such as SOD, CAT, PO and histological structure of abalone foot muscles due to chlorine contamination. Collection of abalone seeds with a 3-4 cm shell size from the abalone hatchery unit, BPIU2K Karangasem Bali. Abalone exposure test using a glass volume of 100 L with a chlorine concentration of 10 ppm. Furthermore, sampling was carried out (hemolime, leg muscles, gonads) at the time of observation (0.12,24,48 hours). Observations included heat shock protein gene expression (Hsp70 and Hsp90) and histology in foot muscles. The results showed that Hsp70 was the highest expressed in hemolime abalone 350 times at 12 hours exposure compared to controls (P <0.05). Meanwhile, Hsp90 at the same time showed the highest level of stress on leg muscles with an expression level of  7 times when compared to controls (P <0.05). It was concluded that the heat shock protein gene was expressed high enough in the chlorine exposure test, however, Hsp70 was more sensitive as a sign of abalone stress as indicated by a higher expression level when compared to Hsp90. Changes in the histological structure show that chlorine contamination can increase the diameter of the sinus hemolime and damage to the epithelial layer of the abalone foot muscles.