Efficacy of green tea extract on removal of the ectoparasitic flagellate Ichthyobodo necator from chum salmon, Oncorhynchus keta, and masu salmon, O. masou
AbstractThe efficacy of green tea extract (GTE) on removal of the ectoparasitic flagellate Ichthyobodo necator (Henneguy, 1883) from the fins and skin surface of infected chum salmon, Oncorhynchus keta, and masu salmon, O. masou, fry is reported. Immersion of infected fry (body weight 0.2–0.9？...
AbstractThe efficacy of green tea extract (GTE) on removal of the ectoparasitic flagellate Ichthyobodo necator (Henneguy, 1883) from the fins and skin surface of infected chum salmon, Oncorhynchus keta, and masu salmon, O. masou, fry is reported. Immersion of infected fry (body weight 0.2–0.9？g) in 0.03% GTE for 30–60？min or 0.3–0.9% GTE for 1–5？min resulted in a decrease of 87.6–100% in chum salmon and 86.5–99.6% in masu salmon in the number of parasites on the dorsal and anal fins in comparison to untreated controls (statistically significant, p<0.01). Scanning electron microscopy showed no parasite present on the skin surface of infected chum salmon fry after a 1？min bath in 0.9% GTE. To clarify the contribution of (−)-epigallocatechin gallate (EGCg), which comprises 14% of GTE, to the efficacy, a 60-min bath with 0.0042% EGCg, equivalent to 0.03% GTE, and a 5-min bath with 0.126% EGCg, equivalent to 0.9% GTE, was evaluated; the number of parasites on the fins decreased 78.3% and 83.5%, respectively. Neither the long (0.03% GTE for 60？min) or short bath treatments (0.3% GTE for 15？min, 0.6–0.9% GTE for 5？min, or 2.7% GTE for 3？min) resulted in any mortality in normal (parasite-free) alevin and fry (0.4–0.7？g) of either species, indicating the safety of the treatments. Moreover, seawater challenge tests of chum salmon fry indicated that the treatments had no effect on the seawater adaptability of normal fish and restored seawater adaptability to infected fish by removing the parasite. Large-scale application of the treatments to approximately 900,000 chum salmon fry (0.4–0.6？g) infected with the parasite in two hatcheries showed that baths in 0.03% GTE for 30？min or 0.6% GTE for 2.5？min resulted in statistically significant decreases of 76.2–90.7% or 98.8–99.4%, respectively (p<0.01), in the number of the parasites on the skin surface and fins in comparison to untreated controls. Cumulative mortalities for 48？h after the treatments were 0.08–0.14%. From our results, we conclude that treatment of I. necator-infected salmonids with GTE is safe, efficacious, and applicable to treatment of large numbers of fish in hatcheries, and that one of the efficacious constituents is EGCg.
AbstractThe efficacy of green tea extract (GTE) on removal of the ectoparasitic flagellate Ichthyobodo necator (Henneguy, 1883) from the fins and skin surface of infected chum salmon, Oncorhynchus keta, and masu salmon, O. masou, fry is reported. Immersion of infected fry (body weight 0.2–0.9？g) in 0.03% GTE for 30–60？min or 0.3–0.9% GTE for 1–5？min resulted in a decrease of 87.6–100% in chum salmon and 86.5–99.6% in masu salmon in the number of parasites on the dorsal and anal fins in comparison to untreated controls (statistically significant, p<0.01). Scanning electron microscopy showed no parasite present on the skin surface of infected chum salmon fry after a 1？min bath in 0.9% GTE. To clarify the contribution of (−)-epigallocatechin gallate (EGCg), which comprises 14% of GTE, to the efficacy, a 60-min bath with 0.0042% EGCg, equivalent to 0.03% GTE, and a 5-min bath with 0.126% EGCg, equivalent to 0.9% GTE, was evaluated; the number of parasites on the fins decreased 78.3% and 83.5%, respectively. Neither the long (0.03% GTE for 60？min) or short bath treatments (0.3% GTE for 15？min, 0.6–0.9% GTE for 5？min, or 2.7% GTE for 3？min) resulted in any mortality in normal (parasite-free) alevin and fry (0.4–0.7？g) of either species, indicating the safety of the treatments. Moreover, seawater challenge tests of chum salmon fry indicated that the treatments had no effect on the seawater adaptability of normal fish and restored seawater adaptability to infected fish by removing the parasite. Large-scale application of the treatments to approximately 900,000 chum salmon fry (0.4–0.6？g) infected with the parasite in two hatcheries showed that baths in 0.03% GTE for 30？min or 0.6% GTE for 2.5？min resulted in statistically significant decreases of 76.2–90.7% or 98.8–99.4%, respectively (p<0.01), in the number of the parasites on the skin surface and fins in comparison to untreated controls. Cumulative mortalities for 48？h after the treatments were 0.08–0.14%. From our results, we conclude that treatment of I. necator-infected salmonids with GTE is safe, efficacious, and applicable to treatment of large numbers of fish in hatcheries, and that one of the efficacious constituents is EGCg.
Cell Tissue Res. Pickering 247 259 1987 10.1007/BF00218307 Sacciform cells in the epidermis of the brown trout, Salmo trutta, and the Arctic char, Salverinus alpinus
J. Fish Dis. Robertson 2 481 1979 10.1111/j.1365-2761.1979.tb00409.x Host-parasite interactions between Ichthyobodo necator (Henneguy, 1883) and farmed salmonids
Robertson vol. 2 1 1985 A review of Ichthyobodo necator (Henneguy, 1883) an important and damaging parasite
J. Fish Dis. Robertson 4 113 1981 10.1111/j.1365-2761.1981.tb01116.x Pathogenesis and auto radiographic studies of the epidermis of salmonids infected with Ichthyobodo necator (Henneguy, 1883)
J. Fish Dis. Roubal 10 181 1987 10.1111/j.1365-2761.1987.tb01060.x Ultrastructural aspects of infection by Ichthyobodo necator (Henneguy, 1883) on the skin and gills of the salmonids Salmo salar L. and Salmo gairdneri Richardson
Sci. Rep. Hokkaido Salmon Hatchery Urawa 46 175 1992 Host range and geographical distribution of the ectoparasitic protozoans Ichthyobodo necator, Trichodina truttae and Chilodonella piscicola on hatchery-reared salmonids
Aquaculture Urawa 110 101 1993 10.1016/0044-8486(93)90264-Y Effects of Ichthyobodo necator infections on seawater survival of juvenile chum salmon (Oncorhynchus keta)
AI-Helper
※ AI-Helper는 부적절한 답변을 할 수 있습니다.