Immuno-physiological effects of dietary reishi mushroom powder as a source of beta-glucan on Rohu, Labeo rohita challenged with Aeromonas veronii.

Beta-glucans have immense potential to stimulate immune modulation in fish by being injected intramuscularly, supplemented with feed or immersion routes of administration. We studied how supplementing Labeo rohita's diet with reishi mushroom powder containing beta-glucan influenced immunological function. A supplemented diet containing 10% reishi mushroom powder was administered for 120 days. Afterwards, analyses were conducted on different immunological parameters such as antioxidants, respiratory burst, reactive oxygen species (ROS), alternative complement activity, and serum immunoglobulin, which resulted significant increases (p < 0.05; p < 0.01) for the reishi mushroom-fed immune primed L. rohita. Additionally, analyzing various hematological parameters such as erythrocytes and leukocytes count were assessed to elucidate the immunomodulatory effects, indicating positive effects of dietary reishi mushroom powder on overall fish health. Furthermore, the bacterial challenge-test with 1.92 × 104 CFU/ml intramuscular dose of Aeromonas veronii showed enhanced disease-defending system as total serum protein and lysozyme activity levels accelerated significantly (p < 0.01). Nevertheless, reishi mushroom powder contained with beta-glucan ameliorated the stress indicating parameters like acetylcholinesterase (AChE), serum-glutamic pyruvic transaminase (SGPT) and serum-glutamic oxaloacetic transaminase (SGOT) enzyme activities results suggested the fish's physiology was unaffected. Therefore, the results indicated that adding dietary reishi mushroom as a source of beta-glucan could significantly boost the immune responses in Rohu.

Impacts of freshwater mussels on planktonic communities and water quality.

Live Freshwater Mussels (FMs) have remarkable characteristics to support other species and the ecosystem. The objective of the study was to identify the planktonic composition; dye absorbance by living FMs; analyze the water quality indicators; and determine the heavy metals from FMs of different rivers in Bangladesh. In order to assess the planktonic composition, planktons were collected from the experimental ponds and then identified under the microscope. Methyl blue (MB) and methyl red (MR) dye absorbance were assessed using live FMs. After co-cultivating Silver barb (Barbonymus gonionotus) with FMs, water quality indicators (including pH, DO, hardness, total dissolved solids, ammonia, nitrite, and nitrate) were recorded. For determining heavy metals (Cu, Cr, Cd, Pb, Zn), mussels (Lamellidens marginalis) samples were collected from different rivers of Bangladesh. The findings of the study showed that the planktons were significantly (p < 0.01) greater in the 'Fish' group, compared to the 'Mussels' and 'Mussels + Fish' groups. Also, the MB and MR dye absorption were significantly higher (p < 0.01) in mussels, indicating that live FMs can accumulate hazardous dyes. Furthermore, the hardness value in the 'Mussels' and 'Mussels + Fish' groups were significantly (p < 0.01) greater than in the 'Fish' group. In addition, the values of nitrite and nitrate in the 'Fish' group were also significantly (p < 0.05) greater than those in the 'Mussels + Fish' group. The heavy metals content in the mussels of the Buriganga river was significantly (p < 0.05) higher compared to the mussels of the Rupsha and Brahmaputra rivers. This study revealed that the live FMs have the profound potential to consume plankton, absorb hazardous wastewater dyes, and maintain good water quality which may serve as the ecological indicators in freshwater environment.