An attempt has been made to isolate the pathogenic fungus from water, body tissue of cold water fish. The hemp seed culture was applied to obtain the fungal colonies and bacteria free pure isolate was obtained by repeated subcultures, using SDA (Sabouraud Dextrose Agar) under aseptic condition and allowed to incubate at 18-200C for 48 hours. Fungal infection was more prominent in the ponds of stagnant water than the running water raceways. The inferior water quality of the stagnant fish ponds supports the virulence of the fungus spores. The muscles of the rainbow trout, fins and gills of the carp were susceptible for the infection. Intensity of the infection in cold water fish species increases with the downfall of the water temperature. The pathogenic fungi in the present study was identified as Saprolegnia parasitica, Saprolegnia diclina and S. ferax with cotton like appearance, elongated zoosporangia and pear shaped primary sporangium.&nbsp;

Isolation of pathogenic fungi from the major cultivated coldwater fish species and their environment in the kumaon region of Uttrakhand

Background: Lepidocephalichthys thermalis is a small indigenous freshwater loach belonging to the family cobitidae and categorized as least concern by the IUCN. L. thermalis holds substantial potential for aquaculture diversification in India because of its ecological adaptability and suitability for captive culture. To identify the most suitable production system, this experiment was performed to assess systems&rsquo; influence on fatty acid composition, digestive enzyme, antioxidant activity and cortisol levels in L. thermalis. 
 
Methods: Over 12 weeks, a controlled evaluation assessed how different production systems including fibre-reinforced plastic (FRP) tanks, raceway tanks, bio floc tanks, cement tanks and lined ponds, which affected fatty acid composition, digestive performance, antioxidant activity and cortisol level in L. thermalis fed a formulated diet. 
 
Result: Elevated concentrations of key fatty acids (&micro;g g-1&nbsp;crude lipid), including alpha-linolenic acid (14.42&plusmn;0.02), eicosapentaenoic acid (14.10&plusmn;0.02), docosahexaenoic acid (20.04&plusmn;0.02), linoleic acid (67.63&plusmn;0.02) and arachidonic acid (6.01&plusmn;0.02), were recorded alongside enhanced digestive enzyme activities (U mg-1&nbsp;protein), comprising protease (59.12&plusmn;0.010), lipase (6.42&plusmn;0.010) and amylase (1.72&plusmn;0.010) in lined pond groups. Concurrently, elevated antioxidant responses (U mg-1&nbsp;protein), including glutathione peroxidase (5.4&plusmn;0.03), catalase (5.9&plusmn;0.01) and superoxide dismutase (5.8&plusmn;0.01), coupled with reduced cortisol concentration (3.240&plusmn;0.02 &micro;g dL-1), collectively indicate a low-stress physiological state in growth of L. thermalis reared under the lined pond groups. Overall, the findings indicate that the lined pond system markedly improve flesh quality in L. thermalis, as evidenced by enhanced fatty acid composition, elevated digestive and antioxidant enzyme activities and reduced cortisol concentrations, reflecting improved physiological performance and stress resilience. 
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Influence of Different Production Systems on Fatty Acid Profiling, Digestive Efficiency, Antioxidant Capacity and Cortisol Hormone Regulation in Lepidocephalichthys thermalis