Journal of Fisheries (University of Rajshahi)
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Bacteria and fungi analyses of fish diets with grasshopper and cockroach meals: the potential replacement of fishmeal in fish diets
Get PDFThe need to further ascertain the quality of fishmeal with biological indicators has poised this study to determine the biological characterisation of formulated diets with supplemented insect protein (variegated grasshopper and American cockroach). The diets (A–F) were prepared with local ingredients (A, 100% grasshopper meal; B, 100% fishmeal; C, 1:1 grasshopper:fishmeal; D, 1:1 cockroach:fishmeal; E, 100% cockroach meal; F, commercial diet). Samples of prepared diets ready to be stored for use were subjected to bacteria and fungi test. Diet F recorded the highest (4.60±1.10×102 cfu g–1) total viable bacteria count. The highest (3.00±0.05×102 cfu g–1) fungi count was recorded in diet A. Six probiotics bacteria were isolated from the diets. Lactobacillus delbrueckii subsp. bulgaricus was only isolated in grasshopper containing diets; as Pediococcus pentosaceus, Bifidobacterium longum, Mycobacterium marinum, Bacillus subtilisand, Lactococcocus lactis were only isolated in diets F, E, D, A and B respectively. Two pathogenic bacteria isolated were Streptoccoci pyogenes and Staphylococcus aureus. Aspergillus flavus and Penicillum sp. are the two species of fungi isolated from diet A, and diets C and E respectively. The diets with insect proteins were rich in probiotic bacteria than other diets may be considered to replace fishmeal in fish diet
Pathology of systemic multiple bacterial infections and peritonitis in hatchery-produced African catfish Clarias gariepinus (Burchell, 1822) larvae
Get PDFDiseases are the major problems that have a significant impact on African catfish Clarias gariepinus seed production. This study reports the necropsy, microscopy, bacteriology and histopathology of diseased catfish larvae that experienced mass mortalities (>80%). The gill filaments of diseased larvae revealed no ectoparasites. The intestines had no parasitic association. About 35 – 40% of the dead larvae had ruptured abdomen. The affected larvae had abdominal haemorrhages and disintegrated intestine with marked degenerative and inflammatory changes, which indicated peritonitis. Bacteria including Aeromonas veronii, Edwardsiella tarda and Pseudomonas putida were isolated from the haemorrhagic exudates of diseased catfish larvae. Histopathology demonstrated dense melanomacrophage aggregates in the spleen. The intestine had extensive degeneration, basophilic margination and disintegration of the mucosal layer. The kidney section suggested a suppurative infection with necrosis of haematopoietic tissue, inflammation of the epithelial tissue, vacuolar degenerations and hypoplastic haematopoietic tissue. Aeromonas veronii and E. tarda immersion challenge at 5×106 cells mL–1 yielded no mortalities under laboratory conditions. Nevertheless, the hatchery management measures and the laboratory analyses supported peritonitis with systemic multiple bacterial infections in the observed large-scale motilities of excessively fed larvae
Data-limited stock assessment of red mullet (Mullus barbatus) from the Iskenderun Bay, the north-eastern Mediterranean Sea
Get PDFStock size and status of red mullet Mullus barbatus were assessed via virtual population analysis and yield prediction analysis using on-board observed length-frequency catch data from the north-eastern Mediterranean Sea. The von Bertalanffy growth parameters obtained were L∞ = 35.4 cm, k = 0.42, t0 = 0.64, tanc = 0.59 and Φ′ = 2.72. Trawl-type selectivity ogive was calculated as 1.57 years corresponding to 17.1 cm TL. The virtual population analysis of M. barbatus indicated that the minimum and maximum fishing mortalities were 0.01 yr–1 and 11.1 yr–1 for the mid-length groups for 8.5 cm and 21.5 cm respectively. The estimated lowest mean biomass and yield were 3.541 t and 31 t at length 8.5, and the highest mean biomass and yield were 13.880 t at length 22.5 cm and 46.086 t at length 21.5 cm respectively. Biological reference points were FMSY = 5.85, F0.5 = 2.3, EMSY = 0.89, E0.5 = 0.77. The values for the current fishing mortality coefficient (Fcur) and the current exploitation rate (Ecur) calculated were 5.3 and 0.89 respectively. The present biological reference points indicate that the stock of M. barbatus in the investigated area is overexploited status and needs urgent management considerations
Molecular characterisation and genetic analysis of aerolysin and haemolysin in Aeromonas hydrophila isolated from diseased Labeo rohita by polymerase chain reaction
Get PDFThe present study investigates pathogenicity of local Aeromonas hydrophila strains by molecular characterisation of two virulence factor genes: aerolysin (aerA) and haemolysin (Ahh1) using polymerase chain reaction (PCR) technique. Phenotypically identified presumptive Aeromonas isolates recovered from diseased Labeo rohita were genetically analysed using type-specific primers by amplifying 309 bp and 130 bp conserved regions of aerolysin and haemolysin genes respectively. The partial nucleotide sequences of aerA and Ahh1 were determined from representative strains in which aerA was confirmed in 75% isolates, whereas Ahh1 was confirmed in 50% isolates. The nucleotide blast results of the representative strains revealed close homology of 95% (aerolysin) and 97% (haemolysin) with published sequences
Effect of emodin on growth performance, antioxidant status, intestinal morphology and heat shock protein gene expressions of freshwater prawn (Macrobrachium rosenbergii)
Get PDFThe purpose of this study was to assess the effect of emodin on biochemical variables, antioxidant activity, heat shock protein gene expression and prawn intestinal morphology (Macrobrachium rosenbergii). Three feeds containing 0 mg kg–1 (T1, control group), 25 mg kg–1 (T2) and 50 mg kg–1 (T3) of emodin were formulated and fed for eight weeks. Alanine aminotransferase, total cholesterol and triglyceride contents were significantly lowered although glucose tended to increase following the emodin remedy. Superoxide dismutase variables in haemolymph were dramatically upgraded, whilst malondialdehyde and superoxide anion situations were significantly lowered when compared to control. Emodin supplementation had no influence on glutathione peroxidase contents. Emodin remedy dropped the expression of HSP60 and HSP90 genes in comparison to the control. In T2, the intestinal epithelial cells were complete, well-organised and tightly affixed to the basement membrane, in discrepancy to the slightly disunited basement membrane in the control group. The emodin-treated prawn individuals had a thicker and full intestinal morphology than the control groups. Supplementation with emodin at dosages of 25 mg kg–1 improved growth performance, blood biochemical, antioxidant capacity and immune gene expression
Prevalence of fish lice, Argulus (Crustacea: Branchiura) in freshwater and two ornamental fishes of Iran
Get PDFFarming and trading of aquarium fish has been considered a popular pastime in the world. Most of Iran's aquarium fish are imported from Asian countries including Indonesia, Malaysia, Thailand and Vietnam. Fish lice (Argulus) is known as one of the most important and common ectoparasites in ornamental fish. Reports indicate that these parasites have been observed in ornamental fish imported to Iran (e.g goldfish Carassius auratus and koi carp Cyprinus carpio). Today, due to mismanagement of some ornamental fish breeding centres in Iran, aquarium fish species such as goldfish may have escaped into the natural waters which increase the risk of transmitting pathogens to native fish. The present work was performed to investigate the outbreak of an ectoparasite Argulus in two ornamental fish of Iran and also to evaluate the possibility of transmission of Argulus to inland freshwater fishes of Iran
Abundance study of fish species from Hel River of Kokrajhar, Assam, India
Get PDFHel River is an important river of Kokrajhar district of Assam, India, which is a great source of freshwater fish. Considering the availability of indigenous fish species in Hel River and consumption of these species by the local people, the prime objective of this study was to study the fishes in the river. The relative abundance of fishes along with the species richness and species evenness were calculated based on fish samplings from August 2014 to July 2015. A total of 1313 individuals belonging to 25 species were recorded, dominated by family Cyprinidae with nine species. The highest relative abundance was recorded for Barilius bendelisis (15.31%) followed by Garra gotyla (14.09%) and Barilius barna (13.78%). This study may serve as an important baseline for sustainable management of Hel River
Some aspects of the reproductive biology of Labeo victorianus (Boulenger, 1901) from Kuja-Migori River basin, Kenya
Get PDFLabeo victorianus is an endemic species to Lake Victoria basin and also a species threatened with extinction status. This study investigated reproductive biology of L. victorianus from Kuja- Migori River basin, Kenya with a view to determining the length weight relationship (LWR), condition factor, fecundity, egg diameter gonado-somatic index (GSI), length at 50% maturity (LM50) and sex ratio. Sampling was done by electrofishing from January 2018 to June 2019. The LWR showed a negative allometric pattern (p < 0.05). The mean condition factor for combined sexes was 1.02. Fecundity ranged from 47842 – 101902 eggs (mean ± SD: 83663 ± 2605 eggs) and correlated highly with body size (r2 = 0.9137). Egg diameter ranged from 0.5 – 0.7 mm. Mean GSI was 6.3 ± 1.6 and 2.8 ± 0.45 for females and males respectively. The LM50 was estimated at 18 cm total length (TL) and 20 cm TL for males and females respectively. Sex ratio did not differ from the expected 1:1. This species has a high fecundity with small sized eggs and males attain sexual maturity earlier than females. The findings of this study provide useful information towards sustainable conservation of L. victorianus in the Lake Victoria basin
Record of zipper loach Paracanthocobitis botia (Hamilton 1822), an ornamental fish from Paschim Medinipur, West Bengal, India
Get PDFParacanthocobitis botia (Hamilton 1822) is an indigenous ornamental fish belongs to family Nemachilidae, mainly reported from north-eastern part of West Bengal. During the present survey of indigenous ornamental fish diversity in Paschim Medinipur district, P. botia has been recorded from Kangsabati River Basin (22°23¢55.0²N 87°20¢33.9²E and 22°24¢31.3²N 87°17¢54.3²E) of Midnapore, as well as Paschim Medinipur district, West Bengal. The specimens have been identified on the basis of morphometric and meristic analyses. Present study reports the extension of distribution of the species up to South-Western part of Bengal
Morphometric, meristic and genetic characteristics of Atlantic bonito (Sarda sarda) in the Black Sea
Get PDFThe Atlantic bonito (Sarda sarda) is a commercially important and popular species in the world as well as in Turkish fisheries sector. In this study, the morphologic and meristic features and genetic characteristics of Atlantic bonito in the Black Sea were examined. We found that most of the morphometric measurements in females were greater than males. Besides, 10 haplotypes were found for COI gene region, 3 haplotypes for 16s gene region and 4 haplotypes for the rhodopsin gene region. Genetic closure was determined in Tirebolu population for the first time