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The present study depicts the disease incidences in the aqua farms of Moyna, West Bengal, India, during 2018-2020 and aqua-drugs used by farmers to combat diseases. A total of 132 fish disease incidences were reported, among which parasitic diseases were the most common (53.03%) followed by bacterial diseases (27.27%), diseases due to poor nutrition and environmental fluctuations (10.61%), and fungal diseases (9.09%), respectively. Out of the 53.03% parasitic disease incidences reported, Argulus (22.86%), Dactylogyrus (17.14%), Gyrodactylus (10.00%), Myxospores (10.00%), Lernaea (8.57%), Ichthyophthirius (5.71%) and Trichodina (4.29%) were the major disease-causing parasites. Among bacteria, Pseudomonas spp. and Aeromonas spp. were the most dominant genera encountered in diseased fish. Labeo catla was the most susceptible fish species followed by Labeo rohita, and Cirrhinus mrigala. Seasonal influence in disease occurrence was noticed. Monsoon and winter were favorable seasons for disease outbreaks. The influence of water quality parameters like hardness, pH, ammonia, total dissolved solids of water, and total organic carbon of sediment had a significant correlation with parasite abundance. Farmers of Moyna were observed to use a wide range of chemicals and aqua-drugs to control diseases and related problems. The majority of the fish farms of Moyna were found using feed additives and supplements (32.00%) followed by sanitizers and disinfectants (24.00%), probiotics (17.00%), anti-parasitic drugs (11.00%), antibiotics (8.00%), and other chemicals (20.00%). Lime (calcium carbonate) and zeolite along with sodium chloride, potassium permanganate, formalin, and calcium hypochlorite were extensively used as disinfectants in Moyna. Farmers being unaware of the adverse consequences of using chemicals and aqua-medicines are fully dependent on private aquaculture consultants for time-to-time advice, which may have augmented their indiscriminate use. Initiative for implementation of better management practices by creating awareness among farmers and adopting strict aquaculture policy guidelines might improve the scenario. [ABSTRACT FROM AUTHOR]

Microfluidic biochips have recently emerged with significant promise and versatility in automating a variety of biochemical protocols on a tiny chip. Sample preparation, which involves the mixing of fluids with a specified target ratio in the minuscule scale, is an essential component of these protocols. Algorithms that optimize on-chip sample-preparation cost and time are closely intertwined with the underlying mixing model, mixing sequence, and fluidic architecture. Although numerous mixing models have been studied in the literature, their impact on the dynamics of mixing steps is hitherto not fully understood. In this article, we show that various mixing models can be envisaged in the light of prime factorization of integers thus establishing a connection among mixing algorithms, chip architectures, and performance. This insight has led to the development of the proposed factorization-based dilution algorithm (FacDA) considering a generalized mixing model suitable for micro-electrode-dot-array (MEDA) biochips. It further leads to target volume oriented dilution algorithm (TVODA) to cater to user’s demand for an output with a given volume. We formulate the optimization problem on the fabric of the satisfiability modulo theory (SMT) while determining mixing sequences. Simulation results on a large number of test-cases reveal that FacDA and TVODA outperform the state-of-the-art dilution algorithms for MEDA biochips with respect to reactant cost, mixing time, and waste production. [ABSTRACT FROM AUTHOR]

The Indian butter catfish, Ompok bimaculatus (Bloch, 1794), is a high-value catfish that has gained immense consumer preference in South-East Asia. However, information on the nutritional requirements of this species is scanty. Hence, an experiment was conducted to evaluate the effects of varying dietary lipid levels on growth, body composition, and activities of digestive and metabolic enzymes in larvae. Three isonitrogenous (40% crude protein) diets were formulated by supplementing fish and vegetable oil (1:1) at 4.5% (D1), 7% (D2), and 9.5% (D3) levels (containing crude lipid 5.7%, 8.0%, and 10.45%, respectively in diets D1-D3) to a fish meal- and oilcake-based formulated diet. Experimental diets were fed to butter catfish larvae (0.15 ± 0.01 g) in triplicate groups for a period of 42 days. Proximate compositions of the experimental diets, as well as fish carcass, were analyzed using standard procedures (AOAC 2005). Digestive and metabolic enzyme activities were analyzed at the completion of the experiment by standard methodology. Butter catfish larvae fed the diet D2 (8% crude lipid) resulted in the best performance in terms of weight gain (final weight 1.40 ± 0.07 g), net weight gain (1.31 ± 0.06 g), specific growth rate (5.50 ± 0.05% · day-1), and protein efficiency ratio (2.39 ± 0.17). The highest lipid deposition (2.90 ± 0.12%) in the carcass was also recorded in fish reared on diet D2. The final weight, net weight gain, protein efficiency ratio, and specific growth rate were significantly (P < 0.05) higher in D2 having 8% lipid. Moisture and lipid contents of the whole body were significantly (P < 0.05) higher in larvae fed diet D2. Amylase activity in fish significantly (P < 0.05) decreased with increasing dietary lipid levels. The maximum alkaline protease, pepsin, and lipase activities were noticed in the larvae fed diet D2. Progressive decrease in liver glucose-6-phosphate dehydrogenase activities and significant increase (P < 0.05) in the activities of neoglucogenic enzymes (glucose-6-phosphatase and fructose-1,6-bis phosphatase) were noticed with an increase in dietary lipid levels. Significantly lower (P < 0.05) activities of LDH, ALT, and AST were recorded in the group fed diet D2. Results of the study indicated that 8% crude lipid in the diet could assure optimum growth and survival of butter catfish larvae during early development. An appraisal on growth, body composition, and digestive as well as metabolic function in the butter catfish larvae recorded in the study might provide some important information to consider application of formulated diets for the larviculture of Ompok bimaculatus. [ABSTRACT FROM AUTHOR]