Multispecies probiotics applications through feed addition on cultured tilapia to prevent streptococcosis

ABSTRACT Streptococcosis is one of the diseases that often arise and can cause death by 100% in tilapia fish farming. This study aimed to determine the most optimal probiotics combination of cells Bacillus cereus P22, Bacillus subtillis ND2 and Staphylococcus lentus L1k through the feed for streptococcosis prevention. The experimental fish with initial body weight of (13.06±0.18 g), were randomly distributed at 25 fish per 60 L water, and reared for 21 days. The fish fed with supplemented feed (except controls) with FR 3%, about three times a day, for 14 days. The treatment of combination probiotics-supplemented feed on, K1 (P22 and ND2, density of 106 CFU/mL), K2 (ND2 and L1k, density of 105 CFU/mL), K3 (P22 and L1k, density of 105 CFU/mL), K4 (P22, ND2 and L1k, density of 106 CFU/mL), the negative and positive control treatment given feed without supplementation. On day 15, the experimental fish, (except negative control) were challenged with Streptococcus agalactiae via intraperitoneal injection 0.1 mL/fish (104 CFU/mL). The results indicated that the best combination was shown by K3 (the combination of Bacillus cereus P22 and Staphylococcus lentus L1k) with cells addition 1% (v/w). The result of K3 survival rate shown 89.33±6.11%, significantly different from the K + and K- wich were 66.67±4.62% and 88.00±8.00%. The highest increased immune value shown by K3 were wich phagocytic index value 64.00±2.65% and respiratory burst activity value 0.07±0.00 OD. Keywords: multispecies probiotics, Oreochormis niloticus, streptococcosis ABSTRAK Streptococcosis merupakan salah satu penyakit yang seringkali muncul dan dapat menyebabkan kematian hingga 100% pada budidaya ikan nila. Penelitian ini bertujuan untuk menentukan kombinasi optimal dari probiotik Bacillus cereus P22, Bacillus subtillis ND2, dan Staphylococcus lentus L1k melalui pakan sebagai upaya pencegahan streptococcosis. Ikan uji berukuran (13,06±0,18 g), secara acak dipelihara dengan kepadatan 25 ekor/akuarium dengan volume air 60 L, dipelihara selama 21 hari dan diberi pakan yang disuplementasi probiotik (kecuali kontrol) dengan perkiraan FR 3% sebanyak tiga kali sehari, selama 14 hari. Perlakuan kombinasi probiotik yang disuplementasi pada pakan yaitu: K1 (P22 dan ND2, kepadatan 106 CFU/mL), K2 (ND2 dan L1k, kepadatan 105 CFU/mL), K3 (P22 dan L1k, kepadatan 105 CFU/mL), K4 (P22, ND2 dan L1k, kepadatan 106 CFU/mL), perlakuan kontrol negatif dan posistif diberi pakan tanpa suplementasi probiotik. Pada