Identification of multi-antibiotic resistant bacteria isolated from Vietnamese climbing perch (Anabas testudineus) on fish farms in Ho Chi Minh City, Vietnam

Climbing perch (Anabas testudineus) is considered a cultured species with high economic value and is widely distributed in several Asian countries, including Vietnam. In climbing perch aquaculture, antibiotic and antibacterial agents have been overused, leading to the emergence of antibiotic-resistant bacteria or genes in the aquatic environment as well as in the seafood products. These antibiotic-resistant bacteria and/or genes can then be spread to human through the food chain, generating detrimental consequences for public health and environment. In this study, 14 bacterial strains were isolated from Vietnamese climbing perch collected from various fish farms in Ho Chi Minh City which possess abnormal symptoms on the outside and in their organs. These bacterial strains were then subjected to several biochemical tests to characterize their colony morphologies. Besides, gene sequencing was performed and as compared to the 16S rRNA, 4 bacterial strains were identified with a high percentage in similarity, including Pseudomonas aeruginosa (99.7%), Aeromonas caviae (99.93%), Kosakonia sacchari (100%), and Edwardsiella ictaluri (99.44%). Additionally, these bacteria showed high levels of antibiotic resistance against beta-lactam, tetracycline, and others. Taken together, these results showed that the four identified bacterial strains isolated from Vietnamese climbing perch circulated in fish farms in Ho Chi Minh City. Their current status of multi-antibiotic resistance indicates further alternative sources of antimicrobial agents, for example, natural compounds, to overcome antibiotic resistance. It is then crucial to identify fish diseases, the associated pathogens, and the new alternatives for antibiotics to protect aquatic ecosystems and water resources.

Taxonomical Accounts of Protozoan Parasites of Climbing Perch, Anabas Testudineus in Bangladesh

The study was conducted to identify the protozoan parasites in a freshwater indigenous air breathing fish, Anabas testudineus. The host fish was collected during mid of the April 2018 to end of the March 2019 from freshwater bodies of Mymensingh, Kishoregonj, Faridpur, Jashore, Manikganj and Bogura districts of Bangladesh. Five species of phylum myxozoa namely Henneguya gigas, Henneguya mystusia, Henneguyaa cerinae, Henneguya periophthalmusi and Myxidium sp., three species of phylum ciliophora namely Amphileptus disciformis, Epistylisl woffi and Trichodina anabasi and one species of phylum mastigophora namely Trypanosoma anabasi were identified in A. testudineus. Myxozoans (97.55%) were clearly dominant group than chiliophorans (2.45%). Bangladesh J. Zool. 49 (2): 331-345, 2021

Embryogenesis of climbing perch fish Anabas testudineus Bloch 1792 at incubation temperature of 28°C

Information on the embryonic development of fish is important to understand the early life history of fish, this information is useful for fish breeding, especially in crossbreeding and genetic engineering. Therefore, this study aimed to observe the process of embryonic development and the incubation time of climbing perch eggs which were incubated at a temperature of 28 °C. The results showed that the embryonic development of betok fish was divided into six phases, namely the cleavage phase (3 hours and 5 minutes), morula (4 hours and 30 minutes), blastula (5 hours, and 40 minutes), gastrula (8 hours, and 47 minutes), organogenesis (15 hours, and 39 minutes) and hatched. At an incubation temperature of 28 °C, the climbing perch fish eggs hatched 18 hours and 38 minutes after fertilization.Introduction

Influence of Water Level on the Exit of Climbing Perch Anabas testudineus out of the Water and Specific Features of Its Movements

Abstract— The study presents the behavior and movement characteristics of climbing perch Anabas testudineus in the “dry maze” installation. Two types of behavior were identified in climbing perch when the water level in the starting tank decreases to the critical value: waiting (often in a compact group at the bottom of the starting tank) or exit to ashore (land) and moving (migration). Movements usually take place in a group of two to four individuals. The fish chose a tank with the water randomly and remained there until the end of the experiment. If individuals become to an empty tank, they, as a rule, leave it and continue to search for water. Thus, the search for a new waterbody is determining the terrestrial migration of climbing perch.

Prevalence of Argulus indicus, histopathology and hematological properties of infected wild fish in Lake Towuti, Indonesia

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.