The Peacock eel, Macrognathus aculeatus is a near threatened highly valuable small indigenous species in Bangladesh. It is not only toothsome nutritive table fish but also notable aquarium species but still rely on natural stock. Keeping in mind the paucity of information on the biology which is crucial to develop artificial propagation and culture technique of this species, the present research was performed as an attempt to contribute to the information on the taxonomy and other biological aspects of M. aculeatus. Total 50 samples were collected from Khulna region during April to May 2014 to assay. The taxonomical study revealed that the total length, standard length, head length, eye diameter, pre and post orbital length; length of dorsal, anal and caudal fin; length of upper and lower jaw; body depth and width, distance between dorsal fin to caudal fin ranged from 17.00-21.00, 15.00-19.00, 0. The mean values of hepatosomatic and alimentosomatic indices persuaded greater liver activity and feeding intensity in M. aculeatus. Moreover, stomach content depicted that the diet of peacock eel composed of small fish species, small prawn, prawn larvae, earthworm, water strider, insects pupae, Metaphire posthuma, Caenorhabditis, sand and mud for instance, which in brief expressed that M. aculeatus is omnivorous in its feeding habits. Indeed, this preliminary research outcome would be utile for the species identification, seed production, developing culture technologies as well as biodiversity conservation of this near threatened fish species.

The research was aimed to determine the present status of probiotics (Lactobacillus spp.) and pathogenic bacteria (Vibrio spp.) of culture pond as well as to determine whether the isolated probiotic Lactobacillus spp. can act as a controlling agent on experimentally pathogenic Vibrio spp. infected Penaeus monodon. In In-vitro test of gills and intestinal tracts, the potential antagonistic activity of Lactobacillus spp. toward Vibrio spp. was gradually observed at 4th hour of probiotic treatment. At 12th hour the viable count of Vibrio spp. was drastically reduced in gill from 2.33×105 to 1.03×103 (CFUg-1) and in intestinal tract 2.35×105 to 6.43×102 (CFUg-1). While, in In-vivo test, in case of muscle, gills and intestinal tract antagonistic activity of Lactobacillus spp. toward Vibrio spp. was noticed after 9 hours, 21 hours and 27 hours respectably of probiotic injected shrimps. However, only the result of in-vitro challenge test revealed that, Lactobacillus spp. significantly reduced the Vibrio spp. viable count of the gills of the selected samples (P=0.037). The investigation showed antagonistic effect of probiotic (Lactobacillus spp.) on experimentally Vibrio spp. infected shrimp. Asian J. Med. Biol. Res. June 2020, 6(2): 311-315

The experiment was conducted to assess and compare the effect of micronutrient enrich commercial inorganic fertilizer and macronutrient enrich traditional inorganic fertilizer on plankton abundance in the manmade earthen ponds of Khulna University pond complex II for a period of three months from August to October 2017. There were three treatments each with three replications. Macro fertilizers (Urea 2.45 g m-1 week-1, TSP 2.45 g m-1 week-1 and molasses–yeast mixture 3.09 g m-1 week-1) were applied in treatment-1 (T1) while commercial inorganic fertilizer (4.5 g m-1 week-1) was applied in treatment-2 (T2) while no fertilizer was applied in treatment-3 (T3). Four different classes of phytoplankton namely Chlorophyceae, Cyanophyceae, Bacillariophyceae, and Euglenophycaea were found in this experiment in which Chlorophyceae (5304.25±223.78 cells L-1) was the dominant class in respect of abundance and number of genera. Additionally, four classes of zooplankton such as Copepoda, Cladocera, Rotifera, Ostracoda were observed in which Copepoda (1559.84±70.48 cells L-1) was the most dominant class in treatment T2 than other treatments. Mean abundance of different phytoplanktons were 8864.77±52.78, 11489.04±295.76, 5983.04±272.88 (cells L-1) in T1, T2 and T3 and mean abundance of zooplankton under treatments T1, T2 and T3 were 3997.65±126.78, 4621.64±45.67, 3017.66 ±137.67 (cells L-1) respectively. The results indicated that mean abundance of phytoplankton and zooplankton were significantly higher (P<0.05) in treatment T2 compared to other treatments. The total mean abundance of plankton was observed significantly higher (P<0.05) in treatment T2 than other treatments. Therefore, it is concluded that micro nutrient rich commercial inorganic fertilizer Bluemix was more effective on the primary production in polyculture ponds as well as increase the production of fish than traditional inorganic fertilizer.

The objectives of this investigation were to seek out the residue level of nitrofurans and chloramphenicol in cultured tilapia muscle in south west region of Bangladesh. Ninety samples were collected randomly from various fish farm of different Upazillas of Khulna, Satkhira and Bagerhat districts during August-December, 2017, where each district was contained 30 samples. Antibiotic residues level present in the animal muscles were detected using ELISA in the Quality Control Laboratory of the Department of Fisheries, Khulna, Bangladesh. To collect information about the status of feed type questionnaire interviews were performed during sample collection from the respective farmers. The overall results revealed that nitrofuran metabolites and CAP residue existed in all the samples within the MRL (Maximum Residue Level) with the exception of 3.33%, 6.66% and 3.33% samples of Khulna, Bagerhat and Satkhira district respectively. Antibiotic residue data showed all nitrofuran metabolites like SEM, AOZ, AMOZ, AHD and CAP were present in all samples in which SEM was highest in Shatkhira district and lowest in Khulna district. In case of AHD, highest residue was found in Khulna and lowest was Satkhira district. Additionally, AOZ was highest in Khulna district and lowest in Bagerhat district and AMOZ was highest in Bagerhat district and lowest Satkhira district. CAP was found highest in Satkhira district while that was lowest in Bagerhat district. The results of the also revealed that contamination of nitrofuran metabolites and chloramphenicol were more in tilapia farms where home-made feed was used compared to commercial feed. Asian Australas. J. Biosci. Biotechnol. 2019, 4 (2), 102-108

A six month’s experiment was carried out in earthen ponds to evaluate the effect of micro and macro nutrients on the growth performance of Prawn (Macrobrachium rosenbergii), Rohu (Labeo rohita) and Mola (Amblypharyngodon mola) in a polyculture system during July to December 2017. The trial was conducted into two different treatments and one control each with three replications. In treatment-1, macronutrients enrich fertilizers like urea, TSP and molasses-yeast mixture were applied at the rate of 2.45, 2.45, and 3.09 (g m-2 week-1), whereas in treatment-2 micronutrients composition mixer applied at the rate of 4.50 g m-2 week-1 while no micro and macronutrients were applied in control. The mean value of all water quality parameters showed no significant differences among control and two treatments when One-way ANOVA was performed except hardness. The average final mean individual weights of prawn, rohu and mola in control, treatment-1 and treatment-2 were 22.10, 24.35, and 24.70 g; 141.10, 190.60 and 182.20 g; 3.36, 3.67 and 3.73 g, respectively. The survival rates of various species namely prawn, rohu and mola in control, treatment-1 and treatment-2 were 73.33, 89.58 and 86.25%; 78.00, 74.00 and 74.00%; 10.67, 15.33 and 15.33%, respectively. There was no significant difference in the survival rates of prawn, rohu and mola among control and treatments. Production after six months of culture was 351.8, 461.5 and 445.3 kg ha-1 in control, treatment-1 and treatment-2, respectively which were significantly different at 5% level of significance. Int. J. Agril. Res. Innov. & Tech. 8 (2): 47-53, December, 2018