Sushil Kumar Garnayak

Efficacy of two avermectins, doramectin and ivermectin against Argulus siamensis infestation in Indian major carp, Labeo rohita

The efficacy of two avermectins, doramectin and ivermectin via oral and parenteral routes and their prophylactic effects against Argulus siamensis infestation in Indian major carp, Labeo rohita was studied. Doramectin and ivermectin were fed once to L. rohita sub-adults naturally infested with A. siamensis parasites at graded levels of 1000, 750 and 500 μg/kg body weight and 500, 300 and 200 μg/kg body weight, respectively. The mean time of clearance of parasites was 24 ± 0.149 h for 1000 and 24 ± 0.210 h for 750 μg of doramectin/kg body weight fish, however, the dose of 1,000 μg resulted in adverse reactions and mortality in fish. A single dose of 500μg/kg body weight of ivermectin also cleared the infestation in 24 ± 0.258 h. In second experiment, L. rohita naturally infested with A. siamensis were administered with doramectin and ivermectin intramuscularly as single dose of 200, 150 and 100 μg/kg body weight. Both doramectin and ivermectin at 200 μg/kg body weight cleared the infestation in 4 ± 0.149 and 4 ± 0.258 h respectively, however, those resulted in adverse reactions viz., black pigmentation, lethargy and poor appetite in fish. The mean time of clearance of parasites from fish was 6 ± 0.210 and 12 ± 0.314 h for doramectin and ivermectin, respectively, when given at a lower dose of 150 μg/kg body weight. The prophylactic effects of both drugs were also evaluated by challenging naïve rohu with metanaupliar larvae of A. siamensis after feeding the fish single dose of the doramectin and ivermectin at 750 and 500 μg/kg body weight, respectively. The effects of both the drugs were found to last for 17-18 days. The effects of bath treatment with doramectin and ivermectin at different concentrations on adult A. siamensis and metanaupliar larvae of A. siamensis were also evaluated. The results suggested that ivermectin could act more rapidly compared to doramectin. However, detailed studies on the toxicity and pharmacokinetics of doramectin and ivermectin upon their administration to aquatic organisms and the environmental impacts of their usage are required to be undertaken before finally recommending the safe use of these drugs for control of parasitic infections.

Mixed infection of Argulus japonicus and Argulus siamensis (Branchiura, Argulidae) in carps (Pisces, Cyprinidae): loss estimation and a comparative invasive pattern study

The genus Argulus is economically one of the most important taxa of crustacean ectoparasites in freshwater aquaculture systems throughout the world. This study investigates the occurrence and effect of a mixed infestation of two species of Argulus, Argulus japonicus Thiele, 1900 and Argulus siamensis Wilson, 1926, in a carp culture farm in Mandi, Himachal Pradesh, India. In this study the economic loss due to argulosis was estimated to be 67 102.00 INR (US

CHARACTERIZATION OF SERUM IMMUNOGLOBULIN IN CHANNA STRIATA (BLOCH) AND KINETICS OF ITS RESPONSE TO AEROMONAS HYDROPHILA ANTIGEN

1428)/ha per year, taking into account factors like mortality, reduced growth rate, and costs associated with drug application. The parasite population of the farm under study was dominated by A. japonicus, which constituted 93.5% of the population, the rest being A. siamensis. The dominance of A. japonicus can be explained by a comparison of the invasiveness of both species through determination of their off-host survival period, fecundity, and infestation pattern. A. japonicus was found to be better adapted to resist starvation, as the maximum off-host survival period for A. japonicus was 6 days, compared to 4 days in A. siamensis at 28°C. The average clutch size of A. japonicus was experimentally found to be 187 eggs, versus 120 for A. siamensis. An experimental mixed infestation of both species was established on Labeo rohita (Hamilton, 1822) to assess their infestation patterns, which proved A. japonicus to be more virulent than A. siamensis. The wide distribution of A. japonicus in comparison to A. siamensis may thus be attributed to its relatively prolonged off-host survival period, higher fecundity, and stronger virulence.

Purification and Molecular Characterization of IgM in Olive Barb, Puntius Sarana

The immunoglobulin (Ig) from the serum of Channa striata was isolated by gel electroelution and characterized further to understand its nature and subsequent applications in studying the immune response. The purity of the sample was confirmed with the presence of a single band on native gradient PAGE and the molecular weight of ∼897 kDa was determined from the gel. In SDS-PAGE, C. striata Ig was reduced to produce two bands corresponding to H (heavy) (∼72 kDa) and L (light) (∼27 kDa) chain subunits. Polyclonal antiserum against the purified Ig was raised in a rabbit and adsorbed with 10% liver tissue homogenate of C. striata to enhance its specificity. By an indirect ELISA standardized using the adsorbed rabbit antiserum, the normal serum Ig concentration in C. striata was estimated to be 3.48 mg/mL. Further, a kinetic study of specific immunoglobulin response to formalin-killed Aeromonas hydrophila antigen was undertaken using another indirect ELISA, which showed a significant increase in serum immunoglobulin titer from day 2 onwards and reached its peak at day 14. Subsequently, the Ig titer was dropped from day 21 onwards till the completion of the experiment at day 42, although it was at a significantly higher level than the control.

Genetic diversity and species identification of Argulus parasites collected from major aquaculture regions of India using RAPD-PCR

In the present article, immunoglobulin (Ig) of Puntius sarana (a vulnerable medium carp species) was purified by affinity chromatography, characterized, and identified as only IgM type with a native molecular weight of 879 kDa having one heavy (88 kDa) and one light (26 kDa) chain. Further, the developed rabbit antisera against IgM was found to be quite specific to P. sarana IgM and used in ELISA to measure the antibody titer in P. sarana at different time periods, against an antigen (hemocyanin) injection with and without adjuvant. The antibody titer was significantly higher in most of the time periods in both groups, however, the adjuvant-treated group showed higher antibody titer at days 43 and 90, compared to non adjuvant-treated group. Further, the partial IgM sequence was amplified and its expression level was checked during ontogenesis. The IgM transcript was detected from unfertilized egg stage to 4 days post fertilization (dpf) and again reappeared at 21 dpf whereas during infection with Aeromonas hydrophila, significantly marked up-regulation of the gene was observed at 12 hr, 24 hr, and 7 days post-infection time periods indicating the role of IgM during early embryonic time period as well as during bacterial pathogenesis.