Investigating the impact of external application of formalin and potassium permanganate on hematological, immunological, and biochemical profiles in Labeo rohita fingerlings.

The present study aimed to elucidate the suitability of formalin and KMnO4 as therapeutics for fish diseases in Indian major carp, Labeo rohita, while considering their impact on fish stress levels. Acute toxicity tests revealed that the 96-hour LC50 values for formalin and KMnO4 were 66.58 ppm and 2.89 ppm, respectively. Sub-lethal concentrations of formalin (6.65 ppm, 3.32 ppm, and 2.21 ppm) and KMnO4 (0.289 ppm, 0.145 ppm, and 0.096 ppm), along with control groups, were administered to the fish for different exposure periods (24, 48, 72, and 96 hours) and different hematological, biochemical, and immunological parameters were analyzed. The findings demonstrated that formalin exposure resulted in a significant decrease (p < 0.05) in hematological parameters, immunological parameters, and serum protein levels. Conversely, formalin exposure led to significant increases (p < 0.05) in serum glucose, SGOT, SGPT, and ALP levels. In contrast, KMnO4 exposure significantly decreased (p < 0.05) hematological parameters and serum protein levels, while significantly increasing (p < 0.05) immunological parameters. To evaluate curative efficacy, challenge studies were conducted using three sub-lethal concentrations of formalin and KMnO4 against Aeromonas hydrophila (ATCC 7966) infection. Based on the aforementioned results, the recommended doses of formalin and KMnO4 were found to be 6.65 ppm and 0.289 ppm, respectively.

A novel approach in valorization of spent mushroom substrate of Cordyceps militaris as in-feed antibiotics in Labeo rohita against Aeromonas hydrophila infection.

The study was carried out to investigate Cordyceps militaris spent mushroom substrate (CMSMS), a renewable biomass, for its effect on fish as an alternative source of in-feed antibiotics. For meticulous examination, four different iso-nitrogenous and iso-caloric diets were prepared containing CMSMS at 0%, 1%, 2%, and 3%. A total of 360 Labeo rohita fingerlings with an average initial weight and length of 12.6 ± 0.04g and 10 ± 0.1 cm, respectively, were blocked into 4 treatments with 3 replicates, i.e., T1 (control), T2 (10 g/kg), T3 (20 g/kg), and T4 (30 g/kg). The feeding trial was conducted for 60 days with samplings on the 7th, 15th, 30th, and 60th days, and blood samples were collected to determine different immunological (NBT, TIg, lysozyme, and antiprotease activity) and biochemical (glucose, total protein, SGPT) parameters. A challenge study was conducted against Aeromonas hydrophila at the end of the feeding trial. The results showed that CMSMS at 30g/kg showed a better immune response over time with increasing doses. All the biochemical readings fall within normal ranges. Fish fed with CMSMS at 30g/kg (3%) have better survival after being challenged with Aeromonas hydrophila. Therefore, Cordyceps militaris spent mushroom substrate (CMSMS) can be biosafely used as in-feed antibiotics in Labeo rohita and can reduce the concern of by-product disposal from mushroom cultivation.

Identification and analysis of pathogenic bacteria causing outbreaks in Indian major carp aquaculture of Tripura.

OBJECTIVE: The objective of this study was to investigate bacterial disease outbreaks in Indian major carp from aquaculture systems in Tripura, India, and identify the bacterial species associated with those outbreaks. METHODS: A 3-year surveillance was conducted in eight districts of Tripura, during which nine bacterial disease outbreaks were recorded. Fourteen bacterial strains isolated from diseased Indian major carp were selected and identified using phenotypic, molecular (16S ribosomal RNA gene), and phylogenetic analyses. In vitro pathogenicity studies were performed to assess the potential pathogenicity of the isolated bacteria. RESULT: The selected isolated strains were preliminarily identified under the genera Aeromonas (9 isolates), Acinetobacter (1 isolate), Citrobacter (3 isolates), and Pseudomonas (1 isolate). Molecular and phylogenetic analyses confirmed the species of the isolated bacteria, including Aeromonas jandaei (strains COF_AHE09 and COF_AHE61), Aeromonas veronii (strains COF_AHE13, COF_AHE52, COF_AHE55, COF_AHE56, and COF_AHE62), Aeromonas hydrophila (strains COF_AHE51 and COF_AHE58), Acinetobacter pittii (strain COF_AHE14), Citrobacter freundii (strains COF_AHE20, COF_AHE57, and COF_AHE59), and Pseudomonas aeruginosa (strain COF_AHE54). Behavioral and clinical signs observed in the diseased fish, such as lethargy, skin hemorrhaging, ulcers, fin and tail rot, exophthalmia, distended abdomen, scale loss, and skin discoloration, indicated the presence of bacterial septicemia. The in vitro pathogenicity studies highlighted the potential role of these bacteria in disease development, especially under environmental stress. CONCLUSION: This study provides valuable insights into the diversity of bacterial species associated with bacterial disease outbreaks in Indian major carp from aquaculture systems in Tripura. It serves as the first comprehensive investigation of its kind, contributing to our understanding of bacterial infections in Indian major carp.

Visible-Light-Induced Metal- and Photocatalyst-Free Radical Cascade Cyclization of Cinnamamides for Synthesis of Functionalized Dihydroquinolinones.

Visible-light-promoted metal- and photocatalyst-free radical cascade cyclization of cinnamamides with α-oxocarboxylic acids is described for sustainable synthesis of diverse pharmaceutically important dihydroquinolinone scaffolds in one pot under mild conditions. The decarboxylative cascade cyclization proceeded efficiently at room temperature without the need for expensive photocatalysts such as Ir or Ru complexes, which indicates the practicability and environmentally benign nature of this protocol. Preliminary mechanistic studies reveal that the blue LED irradiation efficiently cleaves the I-O bond of the hypervalent iodine reagent PhI(O2CCOAr)2 formed through ligand exchange between iodobenzene diacetate and arylglyoxylic acid to initiate the cascade reaction. The synthetic value of this operationally simple and energy-efficient method is further demonstrated by late-stage functionalization of drug molecules in excellent yields.

Ameliorating effects of dietary mixture of Withania somnifera root extract and vitamin C in Labeo rohita against low pH and waterborne iron stresses.

The present study was conducted to elucidate the possible effect of a combination of Withania somnifera (Ashwagandha) root extract and dietary l-ascorbic acid (vitamin C) on the immune responses and survivability in Labeo rohita fingerlings against low pH and waterborne iron toxicity. Four diets were prepared containing 0% (control), 0.01% (T1), 0.1% (T2) and 1.0% (T3) of a combination of Withania somnifera (Ashwagandha) root extract and dietary l-ascorbic acid (vitamin C) at the rate of 1:1 (w/w). Fishes were fed for 60 days to find out the best dose and duration of feeding by examining different haematological (haemoglobin, haematocrit, total RBC count, total WBC count, MCV, MCH and MCHC), immunological (NBT, lysozyme and total immunoglobulin activity) and biochemical (glucose, total protein, ALP, SGPT and SGOT level) parameters on 7, 15, 30 and 60 days of feeding. The best response was observed in fish fed with diet T3 within 15 days. The result showed a significant (p < 0.05) increase in haemoglobin, haematocrit, total RBC count, total WBC count, NBT, lysozyme activity, total immunoglobulin and total protein whereas a significant (p < 0.05) decrease in glucose, ALP, SGPT and SGOT level compared to control. Challenged study against waterborne iron (6.02 mg l-1) and low pH (4.2-4.5) after feeding the fish for 15 days with diet T3 showed significantly (P < 0.05) higher protection than control. The study concludes that inclusion of 1.0% Withania somnifera (Ashwagandha) root extract and dietary l-ascorbic acid (vitamin C) combination in diet have a stimulatory effect on immune response and reduces the effect of multiple stresses (i.e., low pH and waterborne iron toxicity) in L. rohita fingerlings.

Effect of miconazole nitrate on immunological response and its preventive efficacy in Labeo rohita fingerlings against oomycetes Saprolegnia parasitica.

This study evaluated the effect of sublethal doses of antifungal drug miconazole nitrate (MCZ) on immunological responses and its role as a prophylactic drug against S. parasitica in Labeo rohita fingerlings. Fish were fed with sublethal doses of MCZ, that is, T1-6.30 mgMCZ kgBW-1 , T2-12.61 mgMCZ kgBW-1 and T3-25.22 mgMCZ kgBW-1 , and sampling was done at different time intervals for 240 hr. Immunological parameters viz. lysozyme activity, oxygen radical production and plasma antiprotease activity showed significant enhancement (p < 0.05) in fish fed with T2 and T3 doses. Expression of immune-relevant genes such as TLR-22 and ß2-M showed significantly higher expression at 6 hr and 24 hr of sampling in both liver and head kidney. However, these genes showed a downregulation after 120 hr of sampling in both the tissues. Preventive efficacy study showed that single dose of MCZ provides protection against oomycetes up to the fourth day of infection. Significantly higher mortality was observed in control diet-fed fish as compared to fish fed with MCZ medicated diet. Thus, it can be concluded that the MCZ can act as a potent antifungal agent for preventing oomycetes infection as well as to enhance the immune response.

DNA Barcoding of Freshwater Fishes of Indo-Myanmar Biodiversity Hotspot.

To develop an effective conservation and management strategy, it is required to assess the biodiversity status of an ecosystem, especially when we deal with Indo-Myanmar biodiversity hotspot. Importance of this reaches to an entirely different level as the hotspot represents the area of high endemism which is under continuous threat. Therefore, the need of the present study was conceptualized, dealing with molecular assessment of the fish fauna of Indo-Myanmar region, which covers the Indian states namely, Manipur, Meghalaya, Mizoram, and Nagaland. A total of 363 specimens, representing 109 species were collected and barcoded from the different rivers and their tributaries of the region. The analyses performed in the present study, i.e. Kimura 2-Parameter genetic divergence, Neighbor-Joining, Automated Barcode Gap Discovery and Bayesian Poisson Tree Processes suggest that DNA barcoding is an efficient and reliable tool for species identification. Most of the species were clearly delineated. However, presence of intra-specific and inter-specific genetic distance overlap in few species, revealed the existence of putative cryptic species. A reliable DNA barcode reference library, established in our study provides an adequate knowledge base to the groups of non-taxonomists, researchers, biodiversity managers and policy makers in sketching effective conservation measures for this ecosystem.

Muli bamboo (Melocanna baccifera) leaves ethanolic extract a non-toxic phyto-prophylactic against low pH stress and saprolegniasis in Labeo rohita fingerlings.

Bamboo (Melocanna baccifera) plant plays a significant role in traditional Asian medicine and it can be used as an alternative to various chemo-therapeutics or prophylactic agents used in aquaculture. In the present study, the 1st experiment was done for the preparation of extracts from bamboo leaves by using 90% alcohol as a solvent. In the 2nd experiment, toxicity study was carried on Labeo rohita fingerlings (average length of 10.3 ± 1.5 cm and weight 18.5 ± 1.5 g) using BLAL (Bamboo Leaf Alcoholic) extract and it did not show any mortalities in fish even at the dose of 20 g kg-1 body weight, which can be regarded as virtually non-toxic with minimal effect. The 3rd experiment was conducted to find out the effect of BLAL extract based isocaloric and isonitrogenous feed (doses: control- 0.0%, diet T1-0.01%, diet T2-0.1%, diet T3-1% BLAL extract kg-1 feed) on the haemato-immuno-biochemical parameters of L. rohita fingerlings (average length 15.7 ± 1.5 cm and weight 20.2 ± 1.5 g). Regular sampling was done (on 7th, 15th, 30th and 60th day of feeding) for different haematological, immunological and biochemical parameters. The study revealed that the best response occurred within 7 days of feeding with BLAL extract and long-term feeding have shown immunosuppressive condition in the fish. In the 4th experiment, fish were exposed to multiple stressors like low pH stress, and Saprolegnia parastica infection after feeding with BLAL extract (0.1%) based feed for 7 days. The study showed that the BLAL extract can make fish resistant to single stress however, not able to reduce the fish mortality under multiple stresses (S. parastica infection under low pH). Thus, it can be concluded that the BLAL has the potentiality to be used as a non-toxic phyto-prophylactic which can induce non-specific immune response, reduces the low pH stress responses and increases the resistance against saprolegniasis under neutral pH condition in rohu fingerlings.

Effects of fluconazole based medicated feed on haemato-immunological responses and resistance of Labeo rohita against Saprolegnia parasitica.

Fluconazole (FLZ) is a new azole antifungal drug having no earlier record of its utilization for the treatment of fish diseases. A 55-days experiment was carried out to delineate the role of FLZ based medicated feed on haemato-immunological responses and prevention of fungal infection in Labeo rohita fingerlings. Three hundred and sixty fingerlings were randomly distributed into four experimental groups in triplicates. Four iso-caloric and iso-nitrogenous purified medicated feeds were prepared with 0, 100, 200 and 300 mg FLZ 100 g-1 feed. Haemato-immunological parameters like erythrocyte counts (EC), haemoglobulin (Hb), leucocyte counts (LC), packed cell volume (PCV), mean corpuscular haemoglobin (MCH), mean corpuscular volume (MCV), mean corpuscular haemoglobin concentration (MCHC), nitro-blue tetrazolium (NBT), albumin, globulin, total plasma protein were studied. The present study revealed that the continuous feeding of FLZ based feed for 15-30 days significantly (P < 0.05) increases the erythropoiesis, heme-synthesis, as well as the leucocytosis in rohu. However, all the doses exhibited equal protection from the infectious S. parasitica after 45 days of continuous feeding.

Effects of Water pH on Life History Parameters of a New Bosminid Cladocera: Bosmina (Bosmina) Tripurae (Korinek, Saha and Bhattachaya, 1999) in Laboratory Condition.

The effects of water pH on life history parameters of Bosmina tripurae have been studied to determine the most suitable water pH desired for the maximum growth and development of this newly discovered cladoceran species. The study was carried out under the laboratory condition at 20 ± 2°C. Five pH ranges 5.0 ± 0.2, 6.0 ± 0.2, 7.0 ± 0.2, 8.0 ± 0.2 and 9.0 ± 0.2 with six replicates for each pH consisting of one animal in each Petri dish (80 × 15 mm) were used for the study. 20 mL of respective test medium was maintained with Chlorella sp. (2 × 104 ± 0.03 cells mL-1) in each Petri dish throughout the experiment. Thirty (30) animals were observed daily to investigate different life history parameters like total life span, age at maturity, number of eggs, neonates and egg batches etc. at different condition. From the study it was found that acidic water (pH 5 ± 0.2) is more suitable for the culture of Bosmina tripurae in laboratory condition.

Feeding pyridoxine prevents Saprolegnia parasitica infection in fish Labeo rohita.

A 60-day experiment was carried out to delineate the role of dietary pyridoxine (DP) in Labeo rohita fingerlings in modulating immunity and prevention of fungal infection. Two hundred and seventy fingerlings were randomly distributed into three treatments in triplicates. Three iso-caloric and iso-nitrogenous purified diets were prepared with graded levels of pyridoxine. Three experimental groups were C (0.0% DP), T1 (0.01% DP) and T2 (0.02% DP). The role of dietary pyridoxine in modulating immunity and prevention of fungal infection was assessed by haemato-immunological parameters like erythrocyte counts (EC), leucocyte counts (LC), haemoglobulin (Hb), packed cell volume (PCV), mean corpuscular volume (MCV), mean corpuscular haemoglobin (MCH), mean corpuscular haemoglobin concentration (MCHC), nitro-blue tetrazolium (NBT), phagocytic activity, albumin, globulin, total plasma protein, albumin/globulin and by challenge study with Saprolegnia parasitica, where relative percentage survival (RPS) were recorded. Hb, PCV, MCV, MCH, NBT, total plasma protein, albumin, globulin contents, lysozyme and phagocytic activity was significantly (P < 0.05) higher in DP fed group. Significantly (P < 0.05) higher RPS was recorded from T2 group fed with 0.02% DP for 45 days. Hence, DP has the capacity to stimulate nonspecific immunity and increase resistance to S. parasitica infection in L. rohita fingerlings.

Low pH, dissolved oxygen and high temperature induces Thelohanellus rohita (myxozoan) infestation in tropical fish, Labeo rohita (Hamilton).

In Labeo rohita, myxozoan infection is very common and here occurrence and distribution of myxozoan gill parasites were studied with an objective to evaluate the relationship between myxozoan infections with different abiotic factors. All ponds were infected with myxozoan infection. Sampling of water and fish was done fortnightly and soil sample on monthly basis for about 6 months. L. rohita is infected with the one myxozoan species Thelohanellus rohita. The first, second and third gill arches showed higher distribution of myxozoans than the fourth one. Posterior hemibranch of second gill arch was the most preferred site for parasite attachment. The mean intensity of parasite was significantly higher (p < 0.05) in the size class of 8-9 cm in comparison to the other size classes. There were profound variability in the prevalence, abundance and mean intensity of gill myxosoporeans from three ponds. During the start of the sampling, myxozoans were present in all the ponds but their intensity varied in different ponds. These may be due to the variability in the abiotic factors of individual ponds. Most importantly acidic pH, lower DO and higher temperature promote myxozoan infestation and their propagation. Low soil pH is also seen to enhance their propagation. Our data clearly highlighted that prevalence, intensity and abundance of T. rohita strongly influenced by the above environmental parameters and suggested that its life cycle is probably effected by their change; our hypothesis must be regarded as speculative as long as further detail study is not carried out.

Effects of water borne iron on spawn of Indian major carps (Catla catla (Ham.), Labeo rohita (Ham.) and Cirrhinus mrigala (Ham.)).

Effects of water-borne iron on Indian major carps spawn were evaluated in the present study. Ferrous sulphate was used to prepare different test iron concentrations. Mrigal had the lowest 96 h LC(50) value of 0.30 ± 0.06 mg L(-1) while rohu had the highest value of 0.73 ± 0.06 mg L(-1) of iron. Accumulation of iron in mrigal spawn was highest whereas it was lowest in catla. Abnormal behaviour and reduced growth were observed in chronic toxicity. Application factors were calculated to establish acceptable ranges and safe levels.