clove and Fish-Diseases

Rhodomyrtustomentosa is a Thai medicinal plant that has been attracting attention for its remarkable antibacterial properties against Gram-positive pathogenic bacteria. The purpose of this study was to evaluate the antibacterial properties of R. tomentosa leaf extract against Streptococcus agalactiae and Streptococcus iniae isolated from infected tilapia.. The anti-streptococcal activity of R. tomentosa was determined using broth microdilution assays.. The extract demonstrated strong antibacterial activity against the fish pathogens, with minimum inhibitory concentrations (MICs) ranging from 7.8‒62.5 µg ml-1. It was found to possess a dose-dependent bacteriostatic effect on this organism. Scanning electron microscopy revealed irregular and long chains of swollen cells, as well as corkscrew shapes andincomplete separation of cell division of S. agalactiae cells following the treatment at sub-MIC. Moreover, S. agalactiae cells pre-treated with the extract became more sensitive to oxidative stress induced by H2O2 than the untreated cells. Based on the mortality of Nile tilapia after intraperitoneal infection of S. agalactiae at median lethal dose (LD50), the pre-treated cells caused a significant (P<0.01) reduction in mortality of S. agalactiae-infected Nile tilapia.. The results suggested that R. tomentosa could be further developed as a simple and effective agent for the treatment of streptococcosis in Nile tilapia.

Topics: Animals; Anti-Bacterial Agents; Cichlids; Drug Synergism; Fish Diseases; Hydrogen Peroxide; Microbial Sensitivity Tests; Microscopy, Electron, Scanning; Myrtaceae; Oxidative Stress; Plant Extracts; Plant Leaves; Streptococcal Infections; Streptococcus agalactiae; Streptococcus iniae

Camu camu, Myrciaria dubia, is an Amazon plant that presents high levels of vitamin C in its composition. Several studies in animals and humans have demonstrated their efficiency in the prevention and treatment of various diseases. However, there are no reports of its properties in fish. The aim of this study was to evaluate the effect of the oral administration of the extract of this plant in the immune parameters in Nile tilapia, Oreochromis niloticus. 400 Nile tilapia (80 ± 5 g) were randomly distributed into 20 tanks with 1500 L capacity each (20 fish/tank). After a week of adaptation to environmental conditions, it was provided a diet for 5 weeks, using different levels of inclusion of camu camu extract: 0, 50, 100, 250, and 500 mg/kg of feed. Each treatment consisted of four replicates. It was obtained 40.5 mg of vitamin C/g of camu camu pulp powder by high-performance liquid chromatography. At the end of the trial period, fish were inoculated with Aeromonas hydrophila in the swim bladder. Samples were taken after 6; 24 and 48 h of the challenge. Results revealed that fish supplemented with this herb showed significant increase (P < 0.05) in white blood cells counts in blood and exudate, burst respiratory activity, lysozyme activity, serum bactericidal activity, direct agglutination, and melanomacrophage centers count. Red blood cells count, hemoglobin, hematocrit, and biochemical profile of fish supplemented with the herb presented no statistical differences compared to control group (P > 0.05). No histopathological lesions were observed in intestine, kidney, spleen, and gills. It can be concluded that the addition of Myrciaria dubia in tilapia feed improves the immune response and the growth after 5 weeks, especially, at a dose of 500 mg/kg.

Topics: Aeromonas hydrophila; Animal Feed; Animals; Cichlids; Diet; Dietary Supplements; Dose-Response Relationship, Drug; Fish Diseases; Gram-Negative Bacterial Infections; Immunity, Innate; Myrtaceae; Plant Extracts; Random Allocation

Topics: Anguilla; Animals; Cestoda; Cestode Infections; Commerce; Fish Diseases; Madagascar; Nematoda; Nematode Infections

Greeniedeets buccaneer n. gen., n. sp. (Hyponeoidae, Siphonostomatoida, Copepoda) infects the olfactory sac of a gulper shark, Centrophorus sp. (Centrophoridae, Squaliformes) off Madagascar. The adult female of Greeniedeets buccaneer n. gen., n. sp. is most easily distinguished from other hyponeoids (Hyponeoidae) by its possession of a genital complex that is horseshoe shaped in dorsal view. An amended family diagnosis for Hyponeoidae and diagnostic key to hyponeoids based on adult females are provided.

Topics: Animals; Copepoda; Female; Fish Diseases; Madagascar; Nasal Cavity; Parasitic Diseases, Animal; Sharks