ABSTRAKPenelitian ini bertujuan untuk mengetahui efektivitas ekstrak daun ciplukan (Physalis angulata) sebagai imunostimulan dalam meningkatkan jumlah leukosit dan aktivitas fagositosis pada ikan nila. Ikan nila yang digunakan berukuran panjang 10-12 cm dan bobot 70-90 g. Ikan tersebut diperoleh dari pembudidaya ikan nila di Desa Riding Panjang Kecamatan Merawang. Penelitian ini menggunakan Rancangan Acak Lengkap tunggal. Rancangan ini terdiri atas lima perlakuan (P), yaitu P1= kontrol positif (penyuntikkan dengan larutan fisiologis), P2= 4% (v/v) (1 mL ekstrak + 24 mL akuades), P3= 8% (v/v) (2 mL ekstrak + 23 mL akuades), P4= 12% (v/v) (3 mL ekstrak + 22 mL akuades) dan P5= kontrol negatif (tanpa penyuntikan). Ekstrak ciplukan diinjeksikan sebanyak 0,1 mL pada setiap ekor ikan secara intra-muskular. Indikator imun yang diamati adalah jumlah total leukosit dan aktivitas fagositosis. Data dianalisis menggunakan analisis sidik ragam (ANOVA). Hasil yang menunjukkan pengaruh antara perlakuan, selanjutnya dianalis dengan uji wilayah berganda duncan. Hasil penelitian menunjukkan bahwa ekstrak ciplukan dapat meningkatkan jumlah leukosit dan aktivitas fagositosis. Dosis terbaik dalam meningkatkan respon imun adalah dosis ekstrak P4= 12% (v/v) ekstrak dengan jumlah total leukosit (12,43 x 108 sel/mL) dan aktivitas fagositosis (46,67%). KATA KUNCI: Physalis angulata; respon imun; aktivitas fagositosis; jumlah leukosit ABSTRACT: The efectiveness of the extract ciplukan leaves (Physalis angulata L.) on the immune system of nile tilapia (Oreochromis niloticus). By: Yusrika Octarina, Eva Prasetiyono, Dwi Febrianti, and RobinThe aim of this research was to determined the effectivity of the extract Physalis angulata as immunostimulant on the amount of total leucocyte count and phagocytosis activity of nile tilapia. The tested fishes were nile tilapia with size of, 10-12 cm in total length, and 70-90 g in weight. The fish were obtained from fish farmers in Riding Panjang village Merawang Sub District. The research was designed in single completely randomized design. There were five levels of treatment (P), with P= positive control (injected with physiological solution), P2= 4% (v/v) (1 mL extract + 24 mL aquadest), P3= 8% (v/v) (2 mL extract + 23 mL aquadest), P4= 12% (v/v) (3 mL extract + 22 mL aquadest) and P5= negative control (without injection). The extract Physalis angulata L. was injected intramuscularly at a dose of 0.1 mL per fish. The immune indicators observed were total leucocyte count and phagocytosis activity). Data analyzed by using analysis of variant (Anova). if there were any significant different between the treatment, analysis continued by duncan"s multiple range test. The results of the research showed that the extract could increase the amount of total leucocyte count and phagocytosis activity. The ciplukan leaves at a dose of 12% (v/v) were the most effective dose in enhancing total leucocyte (12.43 x 108 cell/mL) and phagocytosis activity (46.67%).