Journal of Fisheries (University of Rajshahi)
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Antibacterial effects of mangrove ethanolic leaf extract against zoonotic fish pathogen Salmonella arizonae
Get PDFThe emergence of multiple drug-resistant pathogens, affecting aquaculture and public health, has put the spotlight on alternative medicine research. This study was conducted to evaluate the In vitro and In vivo antibacterial activity of mangrove ethanolic leaf extract (MLEE) against Salmonella arizonae isolated from Carassius auratus. In vitro, antimicrobial activity of 10 mangrove species and 13 commercial antibiotics were determined using the agar diffusion method. MLEE with the highest antimicrobial activity were subjected to qualitative phytochemical tests and bioassay experiments. In vivo antibacterial activity of MLEE was assessed using C. auratus intraperitoneally injected with S. arizonae. Results showed that Sonneratia alba has the highest antimicrobial activity against S. arizonae followed by Avicennia marina, A. officinalis, Sonneratia ovata, Rhizophora mucronata, Excoecaria agallocha, and Bruguiera cylindrica. However, bacterial isolate was resistant to A. rhumpiana, Scyphiphora hydrophyllacea, and Laguncularia racemosa. Interestingly, S. alba has comparable antimicrobial activity with amoxicillin, trimethoprim, novobiocin, and cefixime. The activity of S. alba could be attributed to the presence of flavonoids, saponin, sterols, tannin, and terpenoids. Moreover, S. alba has reduced and delayed the onset of goldfish mortality infected with S. arizonae. Based on these findings, the S. alba MLEE, is a potential antimicrobial resource against S. arizonae
A brief review of the geographic ranges and ecological effects of three major invasive cyprinid species in Iran
Get PDFThe present study aimed to investigate the distribution status and ecological effects of the introduction of three major invasive fish species viz. Hemiculter leucisculus, Carassius auratus and Pseudorasbora parva in Iran. This review provides useful information about non-native species for readers. This research can play an important role to protecting aquatic ecosystems in Iran and other parts of the world
Gonadal histology of the tiger barb Puntius tetrazona (Cyprinidae)
Get PDFThe ornamental fish industry constitutes a big portion of the economy in many countries of the world. Thousands of attractive fish species are traded annually. The tiger barb Puntius tetrazona is one of the most charming freshwater aquarium species worldwide. The present paper aimed at expanding the knowledge of the reproductive biology of this tropical fish. The ovary and the testis tissues of the tiger barb were embedded in paraffin following routine histological processes, stained with hematoxylin and eosin and Mallory’s trichrome techniques, and investigated by light microscopy. Histological examinations confirmed asynchronous-type ovaries resembling four different developmental stages including primary growth, cortical alveolar, vitellogenic and maturation. In the testis, primary spermatogonia, secondary spermatogonia, primary spermatocytes, secondary spermatocytes, spermatids and spermatozoa were identified. All oogenetic and spermatogenetic phases and mature germ cells occurred simultaneously in the tiger barb. This feature allows this tropical fish to breed rapidly and helps expanding its global trades
Microbiological assessment of Nile tilapia Oreochromis niloticus collected from different super shops and local market in Dhaka, Bangladesh
Get PDFThe present study was conducted to detect the bacterial contamination of Nile tilapia Oreochromis niloticus collected from super shops and local market of Bangladesh. The sample specimens were collected from three super shops in Dhaka city viz. Agora, Shwapno and Prince Bazar and one local market (Savar Bazar). Samples were analysed to determine some pathogenic bacterial genera through the isolation and enumeration from different organs. The isolates were identified as Escherichia coli, Salmonella spp., Shigella spp. and Vibrio spp. by conventional culture method, biochemical tests and PCR assay. Total Viable Bacterial Counts (TVBC) were also determined. Fishes were found to be contaminated within a range between 6×104 to 1.6×106 cfu g–1. The load of E. coli and Shigella spp. were higher than that of Salmonella spp. and Vibrio spp. in all the studied samples. The study concludes that more precautions are required for personnel hygiene during fish processing and handling in order to prevent assemblage of pathogenic bacteria in super shops as well as local fish markets of Bangladesh
Development and quality evaluation of small rock oyster sauce from Saccostrea spp.
Get PDFSmall rock oyster (Saccostrea spp.) are abundant in the Province of Samar and presently there is no oyster sauce produced from this species available in the Philippine markets. Hence, this study aimed to produce small rock oyster sauce at different concentrations (i.e. 70, 80 and 90%; treatments 1–3) and investigated their microbial and sensorial qualities. Based on the result of the overall acceptability of sensory evaluation, treatment 1 containing 70% of small rock oyster extract showed no significant difference with the control commercial oyster sauce suggesting that the treatment 1 is the most acceptable product. There is no microbiological standard limit for fermented fishery products in the Philippines. The total plate counts of the treatments ranged from 3.64 to 4.62 log CFU ml–1. Halophilic bacteria were present in all treatments, ranging from 3.49 – 4.67 log CFU ml–1. Also, lactic acid bacteria were detected in all treatments, ranged from 1.75 – 3.07 CFU ml–1. This study concludes that the small rock oyster sauce produced locally can compete with the available commercial oyster sauces in the market
Are haematological and biochemical properties of freshwater spotted snakehead Channa punctata (Bloch, 1793) season and sex dependent?
Get PDFFreshwater murrel, Channa punctata commonly known as “spotted snakehead” is a popular fish because of its taste and price. Haematological and biochemical profile of fish helps in understanding the fish health and play an important role in fisheries management. The present work was carried out to determine season (summer, monsoon and winter) and sex dependent variations in the blood profile of C. punctata. Haematological [red blood cell counts (RBC), packed cell volume (PCV) and haemoglobin (Hb)] and serum biochemical parameters [blood glucose, total protein, cholesterol, triglyceride (Tg), low density lipoprotein (LDL), very low density lipoprotein (VLDL), high density lipoprotein (HDL), serum calcium levels] of C. punctata were analysed which varied significantly with seasons (p < 0.05). The level of glucose, total protein, Tg, VLDL, RBC, Hb and PCV was low during monsoon season because of the growth and development of gonads compared to the summer and winter season. The level of cholesterol and LDL was high during monsoon. However, haematological and biochemical parameters were not sex dependent. The seasonal haematological and biochemical variations in the fish were mainly due to the physiological acclimatisation of the fish to variations in the environmental condition and feeding regime
Socio-economic status of fisherwomen community in coastal Vizianagaram district of Andhra Pradesh, India
Get PDFThe socio-economics of six fisherwomen co-operative societies in coastal Vizianagaram district of Andhra Pradesh were studied through field surveys by interviewing a total of 185 respondents. Respondents were mostly middle aged (31 – 56 years; 61.6%) living in nuclear families (64.9%). Majority of the fisherwomen were found illiterate (88.1%). A greater proportion (84.9%) of fisherwomen involved in fish marketing as a primary occupation followed by salting and curing (9.73%) and pickling of fishes (5.4%). More than half (56.2%) of the respondents earned > Rs. 25,000 (USD$ 1 = Rs. 75) every month. The study revealed that the socio-economic condition of the fisherwomen in the study area is poor, with a high percentage of the illiteracy. Necessary steps should be taken by the Governments organizations, NGOs and respective stakeholders to improve the literacy level as well as livelihood status
The olfactory organ in the Gangetic catfish Ailia coila (Hamilton, 1822): structural and functional aspects
Get PDFA study of the olfactory organ, with marked observation on cellular morphology of neuroepithelium was carried out in riverine catfish Ailia coila (Hamilton, 1822) using light and scanning electron microscopy. The elongated olfactory rosette within olfactory chamber was made up of 16 ± 2 leaf lets, the lamellae which connected laterally on the longitudinal central axis. The lamella consisted of two layers of epithelium enclosing the central core which contained connective tissue stroma along with blood vessels and nerve fibres. The epithelial lining displayed unequal compactness, was comprised of sensory receptor cells, undifferentiated basal cells, secretory mucous cells and two types of supporting cells differentiated as ciliated columnar or nonciliated oval type. Olfactory cells were identified by their staining emphasis, architecture, surface feature and distribution pattern in the mucosa. The surface of sensory epithelium was embossed with structurally distinct ciliated, microvillous and rod receptor cells for procuring olfactory stimuli from aquatic surroundings. The structural composition of the olfactory organ was dissertated with chemosensory system of the fish involved
Relationship between cortisol and glucose as physiological stress indicators during growth season in juvenile Siberian sturgeon Acipenser baerii
Get PDFThe relationship between cortisol and glucose was studied in two-year old farmed Siberian sturgeon Acipenser baerii with a body weight of 340±30 g (mean ± SD) and total length of 45±1 cm from August to November 2017. Thirty-six individuals were randomly selected and stocked in some 3×300 L fiberglass tanks. Blood samples were collected monthly from the tagged fish. The mean cortisol in August, September, October and November were 4.7±0.9, 23.5±3.0, 6.3±0.9 and 7.4±0.9 ng mL–1 respectively whereas glucose concentrations were 44.6±0.4, 27.3±0.6, 49.2±0.7 and 48.5±0.7 mg dL–1 respectively indicating a significant increase in cortisol and decrease in glucose in September, may be due to the exposure to prolonged high temperature (26–28.5°C). Although it was expected to happen naturally due to hyperglycemia of cortisol but no such phenomena was detected. Our results suggest that the consumption of glucose for maintenance of homeostasis and physiological status is a mechanism against the non-optimal thermal regime. This mechanism consumes glucose at a rate higher than that produced by cortisol, causing significant decrease of plasma glucose. In general, there was a reverse relationship between cortisol and glucose concentration during the experiment in Siberian sturgeons
Effects of different background colors on adult spawning, egg hatchability, and larval survival of zebrafish (Danio rerio)
Get PDFBackground color has significant effects on the reproductive and survival performance of fish species. While zebrafish (Danio rerio) is a popular species in laboratory and recreational aquaculture, very little has been known about its background color preference. Thus, this study evaluated the effects of different colors of aquaria on the spawning, hatching, and survival of this species. The study found that zebrafish do not have color preference for spawning. Though red and black backgrounds are statistically comparable, these colors showed significantly higher (P < 0.05) hatching and survival rates than other colors used in this study. Furthermore, performance of red was higher than black but it was not statistically significant. This study reveals that, among all colors evaluated, red is the most suitable for hatching of zebrafish eggs and survival of its larvae whereas, yellow and transparent should be avoided