Aplikasi Mineral Mix terhadap Kualitas Air dan Kinerja Pertumbuhan Udang Vaname pada Kepadatan Berbeda dalam Sistem Low Water Exchange

Abstract

Budidaya udang vaname (Litopenaeus vannamei) dengan sistem low water exchange (LWE) menjadi alternatif untuk meningkatkan efisiensi penggunaan air dan biosekuriti, namun berpotensi menurunkan kualitas air akibat akumulasi limbah organik pada kepadatan tebar tinggi. Penelitian ini bertujuan mengevaluasi pengaruh suplementasi mineral mix pada sistem budidaya LWE dengan kepadatan tebar berbeda terhadap kualitas air, respons fisiologis, dinamika bakteri, dan performa pertumbuhan udang vaname. Penelitian menggunakan rancangan acak lengkap faktorial dengan dua faktor, yaitu kepadatan tebar (100, 150, dan 200 ekor m?²) dan dosis mineral mix (0,00; 0,20; dan 0,30 ppm), masing-masing dengan tiga ulangan. Udang dipelihara selama 28 hari dengan pergantian air maksimum 5% per hari. Parameter yang diamati meliputi kualitas air, specific growth rate (SGR), feed conversion ratio (FCR), survival rate (SR), glukosa darah, enzim superoxide dismutase (SOD), rasio RNA/DNA, total bacterial count (TBC), dan total Vibrio count (TVC). Data dianalisis menggunakan repeated-measures ANOVA dan ANOVA dua arah, dilanjutkan uji Duncan pada taraf nyata 5%. Hasil menunjukkan bahwa kepadatan tebar memberikan pengaruh lebih besar dibandingkan dosis mineral mix terhadap sebagian besar parameter. Peningkatan kepadatan menyebabkan penurunan oksigen terlarut, potensial oksidasi-reduksi, dan alkalinitas, serta meningkatkan total padatan tersuspensi, total amonia nitrogen, nitrit, nitrat, dan fosfat. Suplementasi mineral mix, terutama dosis 0,20 dan 0,30 ppm, mampu memperbaiki kualitas air pada kepadatan rendah hingga sedang melalui penurunan akumulasi nitrit dan dukungan terhadap proses nitrifikasi. Perlakuan tersebut juga meningkatkan aktivitas bakteri menguntungkan (TBC), menekan TVC, meningkatkan konsentrasi SOD, mempertahankan rasio RNA/DNA, serta menghasilkan pertumbuhan dan sintasan yang lebih baik. Sebaliknya, pada kepadatan 200 ekor m?² efektivitas mineral mix menurun akibat tingginya beban limbah organik yang memicu peningkatan stres fisiologis dan oksidatif. Berdasarkan seluruh parameter yang diamati, pemberian mineral mix dosis 0,20 ppm pada kepadatan tebar 150 ekor m?² merupakan perlakuan optimal untuk mendukung budidaya udang vaname yang lebih produktif dan berkelanjutan dalam sistem LWE.

Intensive Pacific white shrimp (Litopenaeus vannamei) culture using low water exchange (LWE) systems has become an increasingly adopted strategy to improve water-use efficiency and biosecurity. However, high stocking densities can accelerate organic waste accumulation, deteriorate water quality, and induce physiological stress, thereby reducing shrimp performance. This study evaluated the effects of mineral mix supplementation under different stocking densities on water quality, physiological responses, bacterial dynamics, and growth performance of L. vannamei cultured in an LWE system. A completely randomized factorial design was applied using three stocking densities (100, 150, and 200 shrimp m?²) and three mineral mix doses (0.00, 0.20, and 0.30 ppm), each with three replicates. Shrimp were reared for 28 days with a maximum daily water exchange of 5%. Water quality, growth performance, blood glucose, superoxide dismutase (SOD) concentration, RNA/DNA ratio, total bacterial count (TBC), and total Vibrio count (TVC) were evaluated. Data were analyzed using repeated-measures ANOVA and two-way ANOVA followed by Duncan's multiple range test (a = 0.05). Stocking density had a greater effect than mineral supplementation on most variables. Increasing stocking density reduced dissolved oxygen, oxidation-reduction potential, and alkalinity while increasing total suspended solids, total ammonia nitrogen, nitrite, nitrate, and phosphate. Mineral supplementation, particularly at 0.20 and 0.30 ppm, improved water quality at low and moderate stocking densities by reducing nitrite accumulation and promoting nitrification. It also increased beneficial bacterial abundance, suppressed Vibrio, enhanced SOD concentration, maintained higher RNA/DNA ratios, and improved growth and survival. At the highest stocking density, however, its effectiveness declined because excessive organic loading limited its ability to alleviate environmental stress. Overall, supplementation with 0.20 ppm mineral mix at a stocking density of 150 shrimp m?² produced the best water quality and shrimp performance, indicating its potential as a sustainable strategy for intensive L. vannamei culture under LWE conditions.