Saurav Kumar

Effect of orally administered azadirachtin on non-specific immune parameters of goldfish Carassius auratus (Linn. 1758) and resistance against Aeromonas hydrophila.

Modulation of the immune responses using active bio-ingredients as a possible prophylaxis measure has been novel prospect for aquaculture. The present study evaluated the effects of azadirachtin EC 25% on non-specific immune responses in goldfish Carassius auratus and resistance against pathogenic bacteria Aeromonas hydrophila. The experimental trial for effects of azadirachtin on immuno-haematoloical parameters in goldfish was conducted by feeding the various levels of azadirachtin as control T(0) (without azadirachtin), T(1) (0.1%), T(2) (0.2%), T(3) (0.4%), T(4) (0.8%) and T(5) (1.6%) for a period of 28 days. Fishes were challenged with A. hydrophila 28 days post feeding and relative percentage survival (%) was recorded over 14 days post infection. Immuno-haematoloical (total erythrocyte count, total leukocyte count, haemoglobin, packed cell volume, NBT activity, phagocytic activity, serum lysozyme activity, myeloperoxidase activity, total immunoglobulin) and serum biochemical parameters (serum glutamate oxaloacetate transaminase (SGOT), serum glutamate pyruvate transaminase (SGPT) and blood glucose) of fishes were examined at 14 and 28 days of feedings. Fish fed with azadirachtin, showed significantly (p < 0.05) enhanced TEC, TLC, Total Ig, total protein, NBT activity, serum lysozyme activity and myeloperoxidase level in different treatment groups in comparison with control group. Similarly, SGOT, SGPT and blood glucose level were found to be significantly (p < 0.05) high but PCV and Hb did not differ significantly (p > 0.05) in the treatment groups compared to control groups. Azadirachtin at the concentration of 4 g kg(-1) showed significantly (p < 0.05) higher relative percentage survival (42.60%) when compared with the control against A. hydrophila infection. This study indicated that azadirachtin EC 25% (4 g kg(-1)) showed higher NBT activity, serum lysozyme, protein profiles, leukocyte counts and resistance against A. hydrophila infection and thus, can be used as a potential immunostimulant in aquaculture.

Effect of dietary supplemented andrographolide on growth, non-specific immune parameters and resistance against Aeromonas hydrophila in Labeo rohita (Hamilton)

The present study evaluated the effect of dietary andrographolide (EC 50%) on growth, non-specific immune parameters and disease resistance against Aeromonas hydrophila infection in Indian major carp, Labeo rohita fingerlings. Fishes were fed with formulated diet containing andrographolide as T0 (0.00%), T1 (0.05%), T2 (0.10%), T3 (0.20%), T4 (0.40%) and T5 (0.80%) for 42 days. Fishes were challenged with A. hydrophila 42 days post feeding and relative percentage survival (RPS) was recorded over 14 days post challenge. Blood and serum samples were collected for nonspecific immune parameters on 14, 28 and 42 days of feeding and growth performance was evaluated at the end of experiment. The results revealed that fishes fed with andrographolide showed significant (p < 0.05) increase in NBT levels, myeloperoxidase activity, phagocytic activity, serum lysozyme activity, and serum antiprotease activity when compared to the control group. The weight gain, specific growth rate, feed conversion ratio and protein efficiency ratio of fishes fed with andrographolide were found to be significantly (p < 0.05) differed compared with control. Dietary andrographolide at the level of 0.10% showed significantly (P < 0.05) higher RPS (74.06%) against A. hydrophila infection than control. The results revealed that andrographolide supplemented diet has a stimulatory effect on non-specific immune parameters along with improved growth performance and increased disease resistance against A. hydrophila infection in L. rohita fingerlings.

Modulation of innate immune responses and induction of oxidative stress biomarkers in Pangasianodon hypophthalmus following an experimental infection with dactylogyrid monogeneans

Abstract Modulation of innate immune activity and oxidative stress response of Pangasianodon hypophthalmus through experimental infection with (Thaparocleidus sp.) dactylogyrid monogenean was studied. A standard cohabitation method was used to infect healthy experimental fish. After 14 days, dactylogyrid (gill monogenean) infested fish were sampled and categorised into three different infected groups namely (T1) low (<10 mean dactylogyrid per gill arch per fish), (T2) moderate (10–49 mean dactylogyrid per gill arch per fish) and (T3) high (>50 mean dactylogyrid per gill arch per fish) along with a control group T0 (un‐infested fish). Serum and tissues (gills and liver) were collected from experimental fish and analyzed for markers of innate immune and oxidative stress, respectively. The results showed that respiratory burst activity, myeloperoxidase level, serum lysozyme, &agr;‐2 macroglobulin and total serum immunoglobulin level were significantly (p < 0.05) elevated in fish with different degrees of parasite infestation compared to the control (un‐infested group). Similarly, cellular oxidative biomarkers superoxide dismutase, catalase, glutathione‐S‐transferase and Na+‐K+‐ATPase activities of gills and liver were significantly (p < 0.05) elevated in dactylogyrid infested fish in comparison to the control. However, significantly decreased level of albumin, albumin to globulin ratio, total serum antiprotease and ceruloplasmin were observed in fish infested with low degree of dactylogyrids, while no significant differences in these parameters were observed between moderately infested and the control groups. The results suggested that varying degree of gill monogenean dactylogyrid infestation not only modulated the innate immune response of P. hypophthalmus by lowering albumin, total serum antiprotease and ceruloplasmin and inducing respiratory burst activity, phagocytic activity, myeloperoxidase, lysozyme, &agr;‐2 macroglobulin and total immunoglobulins, but also the oxidative stress biomarkers. The baseline data obtained in the present study will be valuable in understanding the host‐parasite relationship and the dynamics of innate, oxidative stress responses and susceptibility of P. hypophthalmus to different degrees of parasitosis. HighlightsInnate immune responses in P. hypophthalmus were studied under various degrees of dactylogyrid infection.Moderate and high dactylogyrid loads suppress ceruloplasmin and serum antiprotease activity.Oxidative stress biomarkers in P. hypophthalmus were induced under various degrees of dactylogyrid infection.Higher dactylogyrid load induces GST and Na + ‐K + ‐ATPase activity in gills and liver.

Evaluation of DNA damage and physiological responses in Nile tilapia, Oreochromis niloticus (Linnaeus, 1758) exposed to sub-lethal diclofenac (DCF)

The frequent bioaccumulation of pharmaceuticals in the aquatic ecosystem has raised a concern about their possible ecotoxicological consequences. DNA damage, haematological changes and activities of oxidative stress enzymes in Nile tilapia, Oreochromis niloticus in response to diclofenac (DCF) exposure were investigated for up to 60 days at the concentrations of 0.17, 0.34 and 0.68mgL-1 in the fish liver. Evaluation of genotoxic effects of the drug in the liver, using single-cell gel electrophoresis, showed DNA damage on exposure at the concentrations of 0.34 and 0.68mgL-1 after day 30. Compared with the control, there was a reduction in haemoglobin and red blood cell counts with a significant increase (p<0.05) in white blood cell counts, mean corpuscular volume and mean corpuscular haemoglobin level after day 30 at 0.34 and 0.68mgL-1. The levels of pack cell volume, red cell distribution width and mean corpuscular haemoglobin concentration were not significant (p>0.05) between the exposed group and the control. The indices of hepatic oxidative stress biomarkers, including lipid peroxidation and carbonyl protein, showed elevated level, depicting a positive correlation with both time and concentration. More so, activity of catalase was inhibited while reduced glutathione level decreased in the liver tissue. There was increase in the activities of superoxide dismutase, glutathione peroxidase and glutathione-S-transferase after 30 days at 0.34mgL-1. Further, activity of Na+-K+-ATPase in the tissue was significantly inhibited (p<0.05) at the end of 60 days. Prolonged exposure to diclofenac at sub-lethal concentration can cause both DNA and oxidative damages in O. niloticus, suggesting the use of oxidative stress biomarkers as early warning signals in environmental monitoring of residual pharmaceutical and assessment.

Nanoconjugation of bicistronic DNA vaccine against Edwardsiella tarda using chitosan nanoparticles: Evaluation of its protective efficacy and immune modulatory effects in Labeo rohita vaccinated by different delivery routes

DNA-based immunization has proven to be an effective prophylactic measure to control aquatic animal diseases. In order to improve the efficiency of vaccine against fish pathogen, novel delivery mechanism needs to be adopted. In the present study we nanoconjugated the previously constructed DNA vaccine (pGPD + IFN) with chitosan nanoparticles (CNPs) by complex coacervation process. After construction of the vaccine, an in vivo vaccination trial was conducted in which 2 groups of rohu (L. rohita) fingerlings were vaccinated with CNPs-pGPD + IFN, one group by oral route (incorporated in feed for 14 days) and the other by immersion route (primary and booster immunised), whereas, a third group was intramuscularly (I/M) injected (initial and booster immunised) with naked pGPD + IFN and subsequently challenged with E. tarda (8.7 × 104 CFU/fish) at 35-day post initial vaccination. The protective immune responses were determined in terms of relative percentage survival (RPS), specific antibody production, non-specific immune response, expression kinetics of immune-related genes and pathological manifestation. Evaluation of RPS analysis revealed that CNPs-pGPD + IFN groups recorded highest RPS (81.82% and 72.73% in oral and immersion vaccinated fish group respectively) while the naked pGPD + IFN injected group showed 63.62% RPS when compared with 55% cumulative mortality of control group. In addition, NBT, myeloperoxidase activity, serum lysozyme activity and specific antibody titre in case of CNPs-pGPD + IFN groups showed higher activities during all the time points. Furthermore, CNPs-pGPD + IFN groups showed significant (p < 0.05) upregulation of different immune gene transcripts (IgHC, iNOS, TLR22, NOD1 and IL-1β) in three immunologically important tissues post immunization (both primary and booster dose) as well as after challenge. Thus, from this study, we can conclude that oral or immersion vaccination with CNPs-pGPD + IFN can orchestrate an effective immunisation strategy in organizing a coordinative immune response against E. tarda in L. rohita exhibiting minimum stress to the host with maximum efficacy.

Recent Technologies for Wastewater Treatment: A Brief Review

There is an unprecedented increase in per capita use of, especially water, during the past few decades. In view of the vital significance of water resources, unsustainable use of water resources would cause serious impediment to the growth of economy and standard of living worldwide. Therefore, new approaches for a sustainable utilization of water resources are of utmost importance for a secure future. In recent past, a number of new wastewater treatment technologies have been developed which paved the way for achieving the sustainability through judicious water resource utilization and management. The new wastewater treatment technology, especially the integration of urban water and waste management systems, is a promising approach for the improvement of sustainability of global water resources.

Triclosan toxicity alters behavioral and hematological parameters and vital antioxidant and neurological enzymes in Pangasianodon hypophthalmus (Sauvage, 1878)

Triclosan and its metabolites are detected in a diverse aquatic environment and are major concerns for various aquatic organisms. The present study investigated the impact of acute and sub-lethal exposure of triclosan on behaviour, activities of acetylcholinesterase and selected antioxidant enzymes, haematological and serum gas-electrolyte parameters of Pangasianodon hypophthalmus. The 96 h LC50 of triclosan for P. hypophthalmus was estimated as 1458 μg L-1. Further, sub-lethal triclosan exposure to 1/15th (97 μg L-1), 1/10th (145 μg L-1) and 1/5th (291 μg L-1) of 96 h LC50 concentration for a period of 45 days lead to decrease in total erythrocyte count, haemoglobin content and packed cell volume of blood while total leukocyte count increased significantly (p < 0.05) as compared to control. A concentration-dependent increase in the serum chloride and decrease in partial pressure of oxygen in blood serum was noted on 45th day. An increased activity of catalase and superoxide dismutase in gill and liver tissues and inhibition of acetylcholinesterase activity in brain was observed on 15th, 30th and 45th day of exposure which was dependent on both - concentration of triclosan and duration of exposure. A significant high activity of glutathione-S-transferase in gill and liver tissue was observed in triclosan exposed groups in comparison to control during the experimental period. The study shows that long-term sub-lethal exposure of triclosan to fish can lead to several physiological alterations such as enzymatic scavenging of oxygen radicals and the normal neurological functions mediated by the enzyme acetylcholinesterase. With increasing anthropogenic activity, the study provides a convincing evidence for the necessity of a regulated use and safer disposal of triclosan to the environment.

A prospective of epidemiological intervention in investigation and management of argulosis in aquaculture

Argulus, an obligate macroectoparasite, infests a wide range of fishes causing severe economic loss to aquaculture industry. The application of chemotherapeutants is the most common approach to combat argulosis. But it is very expensive and has a range of negative impacts on the host and environment. An alternative to the extensive use of chemotherapeutics is to restrict Argulus infestation by adopting a range of biosecurity and quarantine measures. However, before adopting these measures it is essential to adequately understand the complex interaction among the host, parasite and environment, in order to identify key factors affecting parasite dynamics and to formulate a possible management strategy. Epidemiology provides key tools to advance our understanding of diseases and allows bringing convergence in controlling the disease. Compared to terrestrial diseases, relatively few epidemiological studies have been conducted to investigate aquatic animal diseases. For Argulus spp., the complex real-world dynamics of transmission, reproduction and the host specificity and the role of these parasites as a vector for various pathogens are very complex to develop an effective epidemiological framework. This review principally focuses on the application of epidemiological concepts, providing insights about the sampling frame, commenting upon the use of simple deterministic susceptible-infected-removed models and examines the determinants of transmission and spread of argulosis. Further, this paper describes the risk factors associated with Argulus infestation and the importance of risk analysis in intervention against its epizootics. Overall, this review is intended to highlight the need for development of a more extensive epidemiological approach to combat argulosis in aquaculture.

In vitro evaluation of natural and synthetic substrate for biofilm formation and their effect on water qualities.

The present study evaluated the natural and synthetic substrate for biofilm formation in in vitro condition and their effect on physico-chemical parameters of water. The four different treatments i.e., control (without substrate), T1 (sugarcane bagasse), T2 (PVC), T3 (coconut husk) and T4 (bamboo strips) as substrates were used for assessment of biofilm formation and heterotrophic bacterial growth. Physico-chemical parameters of water and total platecolonies were estimated at weekly intervals for five weeks. Results of dissolved oxygen, total alkalinity, as well as nutrients like ammonia-nitrogen, nitrate-nitrogen and nitrite-nitrogen showed significant (p