salinomycin and Fish-Diseases

The present study was undertaken to investigate the antiparasitic activity of extracellular products of Streptomyces albus. Bioactivity-guided isolation of chloroform extracts affording a compound showing potent activity. The structure of the compound was elucidated as salinomycin (SAL) by EI-MS, 1H NMR and 13C NMR. In vitro test showed that SAL has potent anti-parasitic efficacy against theronts of Ichthyophthirius multifiliis with 10 min, 1, 2, 3 and 4 h (effective concentration) EC50 (95% confidence intervals) of 2.12 (2.22-2.02), 1.93 (1.98-1.88), 1.42 (1.47-1.37), 1.35 (1.41-1.31) and 1.11 (1.21-1.01) mg L-1. In vitro antiparasitic assays revealed that SAL could be 100% effective against I. multifiliis encysted tomonts at a concentration of 8.0 mg L-1. In vivo test demonstrated that the number of I. multifiliis trophonts on Erythroculter ilishaeformis treated with SAL was markedly lower than that of control group at 10 days after exposed to theronts (P < 0.05). In the control group, 80% mortality was observed owing to heavy I. multifiliis infection at 10 days. On the other hand, only 30.0% mortality was recorded in the group treated with 8.0 mg L-1 SAL. The median lethal dose (LD50) of SAL for E. ilishaeformis was 32.9 mg L-1.

Topics: Animals; Antiprotozoal Agents; Ciliophora Infections; Cyprinidae; Fish Diseases; Hymenostomatida; Pyrans; Streptomyces

The potential antiparasitic and immunomodulatory effect of three treatments against myxosporean parasites on the innate immune system of sharpsnout sea bream (Diplodus puntazzo) was investigated. Fish naturally infected with Myxobolus sp. (Bivalvulida/Platysporina), a histozoic parasite mainly affecting the renal interstitial tissue, were treated by oral administration of a combination of salinomycin with amprolium, Origanum essential oil or fumagillin in a small-scale field trial. Various leucocyte functions influenced by myxosporean infection were examined in order to determine treatment effects on leucocyte immunocompetence of treated fish. One month post treatment all drugs caused a significant decrease in prevalence and intensity of infection in comparison to untreated, infected fish. The effect was most prominent in salinomycin with amprolium treated fish, which 1-month post treatment contained either no cysts at all or a few spores free in melanomacrophage centres revealing almost total elimination of the parasite and the antiparasitic action of the treatment. There was no histopathological evidence of drug toxicity. Antiparasitic action was accompanied by a significant enhancement of phagocytic activity demonstrated by ingestion of large numbers of latex beads and the secretion of high levels of reactive nitrogen intermediates by phagocytes in vitro. Complete restoration of the diminished mitogenic responses and serum lysozyme secretion was also detected in salinomycin with amprolium-treated fish compared to untreated, infected fish. These data suggest that salilomycin with amprolium may be a promising treatment for myxosporean infections in intensively cultured warm-water fish, exhibiting action partially via the enhancement of host, innate immune functions and leading to parasite elimination.

Topics: Amprolium; Animals; Antiprotozoal Agents; Cell Proliferation; Cyclohexanes; Eukaryota; Fatty Acids, Unsaturated; Fish Diseases; Histocytochemistry; Kidney Diseases; Leukocytes; Mediterranean Sea; Muramidase; Oils, Volatile; Phagocytosis; Protozoan Infections, Animal; Pyrans; Reactive Nitrogen Species; Sea Bream; Sesquiterpenes

This study tested drugs and therapeutic compounds to determine effective commercial treatment for fishes infected with myxosporeans. Two series of shore-based experiments and 1 field trial were performed. For the shore-based experiments we used Puntazzo puntazzo (ca. 20 g weight) with kidneys infected with Myxobolus sp. Initially, 6 different doses of Fumagillin, 2 doses of Toltrazuril, and 1 dose of Amprolium, ESB3 and Salinomycin were tested. In the second shore-based experiment, infected fish were treated with Origanum essential oils, Toltrazuril with propylene glycol, Amprolium, and a combination of Salinomycin 12% + Amprolium (SA). In the field trial, P. puntazzo (ca. 165 g) infected with the parasite were treated with SA, Origanum essential oils and Fumagillin. In all trials, the drugs were added to the feed and administered according to the selected regimen. Their efficacy was evaluated in terms of mortality (acceptable level was <3%), pathology and prevalence rate of Myxobolus sp. Lesions were observed only in fish treated with Fumagillin and Toltrazuril. Pathology due to treatment with Fumagillin was observed only at doses > 6 mg kg(-1) body wt for 6 wk in the interstitial renal tissue, where slight inflammation arose. The highest dose tested (25 mg kg(-1)) also produced necrosis in the interstitial tissue, degeneration of the epithelial cells of the tubules and a reduction in melanomacrophage centre numbers. The SA combination proved the most effective treatment for Myxobolus sp. infection of P. puntazzo as (1) the therapeutic regimen and commercial product was not toxic and (2) a significant reduction occurred in the prevalence rate.

Topics: Amprolium; Animals; Antiprotozoal Agents; Aquaculture; Dose-Response Relationship, Drug; Fish Diseases; Histological Techniques; Kidney; Origanum; Phytotherapy; Plant Oils; Protozoan Infections, Animal; Pyrans; Sea Bream; Triazines

The chemotherapeutic efficacy of 6 in-feed compounds against Ichthyophthirius multifiliis Fouquet, 1876 was assessed using experimental infections of rainbow trout Oncorhynchus mykiss (Walbaum) fingerlings. Trial doses of 104 ppm amprolium hydrochloride or 65 ppm clopidol fed to fish for 10 d prior to infection significantly reduced the number of trophonts establishing in trout fingerlings by 62.0 and 35.2% respectively. In-feed treatments of infected trout with either 63 or 75 ppm amprolium hydrochloride, 92 ppm clopidol, or 38, 43 or 47 ppm salinomycin sodium for 10 d also significantly reduced the number of surviving trophonts by 77.6 and 32.2% for amprolium, 20.1% for clopidol and 80.2, 71.9 and 93.3% respectively for salinomycin sodium.

Topics: Administration, Oral; Amprolium; Animal Feed; Animals; Antiprotozoal Agents; Ciliophora; Ciliophora Infections; Clopidol; Decoquinate; Dose-Response Relationship, Drug; Fish Diseases; Monensin; Nicarbazin; Oncorhynchus mykiss; Pyrans; Random Allocation; Treatment Outcome

When given orally, quinine or salinomycin cause irreversible damage to the plasmodial developmental stages of Henneguya sp., a gill parasite in the tapir fish Gnathonemus petersii. Naturally infected tapir fish measured 75-169 mm in total length and their total weight ranged over 4.3-11.7 g. The fish bore 7-77 plasmodia in their gill arches. Medicinal food containing either quinine (5 g/1000 g food) or salinomycin (0.075 g/1000 g food) was given once a day to naturally infected fish in a food chain via water fleas ( Daphnia spp) for a period of 3, 6, or 9 days. From the monitored feeding of the tapir fish and weight determinations of the water fleas, it was calculated that gross uptake was 18.5 micro g/kg body weight fish daily for pure salinomycin and was 1.25 mg/kg body weight daily for quinine. After the end of the experiments, the fish were sacrificed and the plasmodia were carefully prepared from the gill arches and processed for transmission electron microscopy. As seen by ultrastructure investigations, for both substances the grade of damage in the parasites correlated positively with the period of application. When quinine was given for a 3-day period, the trophozoite ecto- and endoplasm exerted numerous vacuoles, caused by the drug, and the presporogonous and the pansporoblastic stages were malformed. Following a 6-day period, numerous abortive polar capsules were found in the trophozoite cytoplasm. To a large extent, the limiting membranes of the polaroblasts and valvogenic cells were destroyed. In addition, deep clefts between the polaroblasts, the valvogenic cells and between the two sporoblasts were observed. Following a 9-day treatment, all damage increased and, in addition, generative cells and two-cell stages were no longer detectable. As a first sign for the effects of salinomycin, following a 3-day treatment, a shrinking of the whole plasmodia occurred and the sutures in the pansporoblasts were enlarged. The polar capsules were malformed and the zonar structures of the polar filament were no longer detectable. The sporoplasmosomes were more electron-pale than those of the control samples. After a 9-day treatment, the pansporoblasts were completely destroyed. Under the experimental conditions chosen, both compounds were very well tolerated by the fishes.

Topics: Administration, Oral; Animals; Antiprotozoal Agents; Electric Fish; Eukaryota; Fish Diseases; Gills; Pyrans; Quinine; Spores, Protozoan

Streptococcosis is a major disease of several fish species in Australia, Japan and South Africa. The minimum inhibitory concentration of some ionophores (lasalocid, monensin, narasin and salinomycin) was determined in vitro for an Enterococcus-like species pathogenic for rainbow trout (Oncorhynchus mykiss) in Australia. Forty isolates of the fish pathogen were tested, together with control strains of Staphylococcus aureus ATCC 29213, Enterococcus faecalis ATCC 29212 and Streptococcus bovis ATCC 9809. The minimum inhibitory concentrations (MIC) of erythromycin, the drug of choice for controlling streptococcosis, ranged between 0.1 and 0.8 microgram/ml whereas the MIC values for the ionophores ranged between 0.2 and 1.5 micrograms/ml. Of the ionophores tested, narasin was the most inhibitory (0.2-0.4 microgram/ml), while monensin was the least inhibitory (0.4-1.5 micrograms/ml). Salinomycin was marginally more inhibitory (0.4-0.8 microgram/ml) than lasalocid (0.8 microgram/ml).

Topics: Animals; Anti-Bacterial Agents; Enterococcus; Erythromycin; Fish Diseases; Gram-Positive Bacterial Infections; Ionophores; Lasalocid; Microbial Sensitivity Tests; Monensin; Oncorhynchus mykiss; Pyrans