UJI KETAHANAN LARVA UDANG GALAH DARI BEBERAPA SUMBER POPULASI TERHADAP BAKTERI Vibrio harveyi

Abstract

Salah satu penyakit yang sering menyerang udang di pembenihan adalah vibriosis, yang disebabkan oleh bakteri Vibrio harveyi. Penelitian bertujuan untuk mengetahui tingkat ketahanan beberapa strain larva udang galah, yaitu asal Sungai Ogan, Sumatera Selatan; Sungai Asahan, Sumatera Utara; Sungai Barito, Kalimantan Selatan; Sungai Ciasem, Jawa Barat; dan strain GIMacro terhadap infeksi bakteri Vibrio harveyi, sebagai dasar perakitan varietas unggul udang galah. Penelitian dilakukan dengan Rancangan Acak Lengkap (RAL) dengan lima perlakuan, yaitu strain larva dan tiga ulangan. Larva udang galah stadia 4 dari 5 populasi berbeda, dengan panjang rata-rata 2,7±0,4 mm ditempatkan di stoples volume 3 L dengan padat penebaran  larva 100 ekor/L. Setiap wadah diisi 1 L air payau 10‰. Selanjutnya diinfeksi bakteri V. harveyi patogen berumur 24 jam dengan kepadatan 105 cfu/mL. Nauplii Artemia diberikan pada pagi dan sore hari. Parameter yang diamati meliputi pengamatan visual abnormalitas larva uji yang dilihat dari tingkah laku larva dan kondisi organ hepatopankreas, tingkat sintasan, kelimpahan total bakteri Vibrio sp. dan V. harveyi, identifikasi bakteri, dan parameter kualitas air. Selama 48 jam perlakuan sintasan larva yang berasal dari strain induk yang berbeda memberikan hasil berbeda nyata dengan tingkat sintasan tertinggi pada larva asal Barito, yaitu 75%; diikuti GIMacro 65%; Asahan 61,33%; Ciasem 53,66%; strain Ogan 20%.

Vibriosis caused by Vibrio harveyi is a serious problem in intensive system hatcheries of freshwater prawn. This study was conducted to study the resistance of larvae from different locations i.e. Ogan River, South Sumatra; Asahan River, North Sumatra; Barito River, South Kalimantan; Ciasem River, West Java; and GIMacro, as part of breeding program to create superior prawn strain. Complete randomized design was used in this study, with 5 treatments, i.e. larvae source and 3 replications. 4th stage of freshwater prawn larvae from the different populations, average total length of 2,7±0,4 mm, were reared in 3 liters buckets with larvae density of 100 larvae/L. Each bucket was filled with 1 L of 10‰ saline water. V. harveyi aged 24 hours was inoculated in each bucket with a density of 105 cfu/mL. Artemia sp. nauplii was given to the larvae twice per day. Some parameters consisting of abnormalitas of larvae, larvae behaviour, hepatopancreas performance, mortality, total of Vibrio sp. number and water quality was observed during the study. During 48 hours of the treatment, showed that factor of different larvae location gave a significant result to larvae survival rate. The highest survival rates was observed in the Barito larvae population (75%), followed by GIMacro (65%), Asahan (61.33%), Ciasem (53.66%), and Ogan 20%.