Infections with Streptococcus spp. were observed in Nile tilapia cultured in net cages in Lake Sentani, Papua, Indonesia. Clinical signs included exophthalmia, erratic swimming, ascites in abdominal cavity, and external hemorrhages. Four types of bacterial colonies (SK, K10, P20, and M12) were isolated from the brain, kidney, and eyes. Based on phenotypic and genetic (16S rDNA sequencing) characteristics, the isolates were identified as Streptococcus iniae (SK), Streptococcus agalactiae (K10 and P20) and Lactococcus garvieae (M12). The latter species has not been previously isolated or reported from fish streptococcosis in Indonesia. Intraperitoneal injection of healthy tilapia with the bacterial species caused significant morbidity (70%) within 3 days and 100% mortality at 6 days post injection. Experimental infections and reisolation of the bacteria from morbid and dead fish suggest they are the causative agents of streptococcosis, which rendered high mortality among cage cultured Nile tilapia in Lake Sentani. Our results suggest the need for developing diagnostic tools for accurate identification of the agents of streptococcosis. As tilapia aquaculture continues to expand as a means of food production and livelihood in Indonesia, it becomes crucial to ensure that fish resources are monitored and protected from the adverse effects of infectious diseases.

Abstract. Amriana, Sari DK, Sriwulan, Anshary H. 2021. Prevalence of Argulus indicus, histopathology and hematological properties of infected wild fish in Lake Towuti, Indonesia. Biodiversitas 22: 3578-3584. Parasites are disease agents that can threaten the health and survival of wild fish as individuals and at a population level. This study aimed to improve knowledge on the prevalence of Argulus indicus, infestation rates and the pathological effects of parasite infestation on hosts as well as hematological properties of infected fish. This study can inform future studies on the prevention and control of the cases of Argulus indicus infestation. Fish from Lake Towuti (20 45? 0? S, 1210 30? 0? E) were caught from February to May 2019 using traps and gill nets. The total of 373 specimens obtained comprised 102 climbing perch (Anabas testudineus), 74 three-spot cichlids (Cichlasoma trimaculatum), 84 Nile tilapia (Oreochromis niloticus), and 113 striped snakeheads (Channa striata). The prevalence, mean intensity and abundance of A. indicus were highest in C. striata with a prevalence of 81%, mean intensity of 5.17 parasites/fish and abundance of 4.06 parasites/fish. The lowest parasite infection level was seen in C. trimaculatum with a prevalence of 4.1%, mean intensity 1.66 and mean abundance of 0.06. Histological analysis showed inflammatory responses in the skin of snakeheads (hemorrhage, increased spread of melanomacrophage and leukocyte cells), melanomacrophage and the spread of leukocyte cells were observed in climbing perch. In contrast, melanomacrophage was often observed in tilapia and trimac cichlid. Blood imaging analysis showed significant differences (P <0.05) in the number of leukocytes and percentage of monocyte cells between uninfested fish and those infested with A. indicus.

The use of probiotics (Lactobacillus  sp.) in feed is one alternative that is done to improve immunostimulants, growth stimulants, and can be used as a balance of microorganisms in digestion. This study aimed to evaluate the growth performance of vanamei shrimp fed with the addition of Lactobacillus  sp. with sweet potatoes in feed. This study used a completely randomized design (CRD) with 4 treatments and 3 replications. The treatment was by feeding with different sweet potato concentrations: A) The dose of sweet potato in feed was 0% (as control); B) The dose of sweet potato in feed was 10%; C) 1The dose of sweet potato in feed was 15%; and D) The dose of sweet potato in feed was 20%. Data were analyzed using variance analysis (ANOVA) and continued with W-Tuckey's further test. The research parameters were digestive enzyme activity, nutrient digestibility, and growth. The results of the variance analysis showed the addition of various sweet potato concentrations with Lactobacillus sp. has no significant effect (p> 0.05) of the growth rate. The specific growth rate of vannamei shrimp ranges from 3.06 to 3.23% / day. Based on the results of the analysis on the utilization of sweet potatoes as a prebiotic on the performance of Lactobacillus sp. in the vannamei shrimps (Litopenaeus vannamei) digestive tract can be concluded that the growth performance does not have a significant effect after being fed with the addition of Lactobacillus sp. and sweet potatoes in feed. Keywords: Enzymes, Digestion, Growth, Lactobacillus sp., Prebiotic, Probiotic.

The use of probiotics (Lactobacillus sp.) in feed is one alternative that is done to improve immunostimulants, growth stimulants, and can be used as a balance of microorganisms in digestion.This study aimed to evaluate the growth performance of vanamei shrimp fed with the addition of Lactobacillus sp. with sweet potatoes in feed. This study used a completely randomized design (CRD) with 4 treatments and 3 replications. The treatment were by feeding with different sweet potato concentrations: A) The dose of sweet potato in feed was 0% (as control); B) The dose of sweet potato in feed was 10%; C) 1The dose of sweet potato in feed was 15%; and D) The dose of sweet potato in feed was 20%. Data were analyzed using variance analysis (ANOVA) and continued with W-Tuckey's further test. The research parameters were digestive enzyme activity, nutrient digestibility and growth. The results of the variance analysis showed the addition of various sweet potato concentrations with Lactobacillus sp. has no significant effect (p> 0.05) of the growth rate. The specific growth rate of vannamei shrimp ranges from 3.06 to 3.23% / day. Based on the results of the analysis on the utilization of sweet potatoes as a prebiotic on the performance of Lactobacillus sp. in the vannamei shrimpis (Litopenaeus vannamei) digestive tract can be concluded that the growth performance does not have a significant effect after being fed with the addition of Lactobacillus sp. and sweet potatoes in feed.

Abstract. Isnansetyo A, Istiqomah I, Anshary H, Sriwulan S, Yudiati E, Subagiyo S, Arif A, Kartikasari DW. 2022. Identification and antibiotic-resistant properties of Vibrio owensii and V. alginolyticus isolated from the Spermonde Islands, Indonesia. Biodiversitas 23: 5995-6005. The Spermonde Islands are located in Makassar Strait, southern Sulawesi, Indonesia, and have attracted the attention of researchers for decades because of their mega biodiversity and abundance of bioresources. However, no study has evaluated the potential mariculture diseases in this area. The present study assessed the potential bacterial fish diseases based on the current status of mariculture in the Spermonde Islands. The samples were collected from three marine aquaculture sites at Barrang Caddi and the Samaloa Islands. Vibrio was isolated on Thiosulfate-citrate-bile-sucrose (TCBS) agar medium. The most common bacterial diseases were observed by bacterial isolation, morphological and biochemical observations, and molecular identification based on 16S rDNA sequence. The microbial, physical, and chemical water qualities at Barrang Caddi and Samaloa Island were suitable for marine aquaculture. Although cultured species in this area did not exhibit gross disease signs, potential opportunistic pathogens of Vibrio were found. The 16S rDNA sequences analysis indicated that the bacterial isolates closed to Vibrio owensii, V. alginolyticus, and V. neocaledonius. Multi-drug resistant V. owensii was identified as a potential pathogen in marine aquaculture. This is the first report on V. owensii isolated from Indonesian marine waters, particularly from the Spermonde Islands. V. alginolyticus was another potential opportunistic pathogen in this area. These results gave the alarm to develop countermeasure methods for potential diseases to minimize the possible outbreak of vibriosis.