Detection of health hazard insecticide dichlorodiphenyltrichloroethane (DDT) in some common marine dry fish samples from Bangladesh

Objectives: The general purpose of this study is to detection and determination of the concentration level of dichlorodiphenyltrichloroethane (DDT) in some commercially available marine dry fishes and to investigate the contamination status of dichlorodiphenyltrichloroethane (DDT) of these dry fishes. Methods: Samples were collected from six largest dry fish markets (three from Chittagong district and three from Cox’s Bazar district) and four types of dry fishes were taken in this study are Ribbon fish (Lepturacanthus savala), Sin Croaker (Johnius dussumieri), Bombay duck (Harpodon nehereus) and Shrimp (mixed species). Total numbers of samples were 24 that were analyzed in the laboratory. Results: The results of the study show that the mean concentrations of dichlorodiphenyltrichloroethane (DDT) in the samples of Ribbon fish, Bombay duck and Sin croaker were ranged between 130.85 - 153.47ppb, 125.21 - 181.4ppb and 119.86 – 208.65ppb respectively. The mean concentrations of dichlorodiphenyltrichloroethane (DDT) were found at a lower amount in shrimp sp. than the other. Conclusions: This result indicates that the concentration of dichlorodiphenyltrichloroethane (DDT) in dry fish samples from Bangladesh are higher and may causes chronic disease and potential long-term risk for human health.

Beneficial roles of nutrients as immunostimulants in aquaculture:A review

Protein deficiency is a major difficulty for human needs in the past few decades,while different types of aquatic species are rich in high quality protein.Therefore,aquaculture is considered as the main developing food production sector globally.Bacterial infections are the main problem for aquaculture,and their outbreaks have a great impact on productivity,and previously indiscriminate use of antibiotics to control them.However,the emergence of multidrug-resistant pathogens might lead to sudden infectious disease outbreaks resulting in serious economic loss.Immunostimulants application is an effective technique to protect and enhance the immune system of aquatic animals and therefore improve aquaculture production.Nutrient immunostimulants such as essential fatty acids,amino acids,vitamins,and minerals are the most important responsibility to improve aquaculture production,as well as the cost of this method,which is effective,non-toxic,and environment friendly.These nutrient immunostimulants are supportive to increase the immune system,antioxidant,anti-inflammatory,and infection resistance of aquatic animals.In addition,nutritional feed additives improved feed palatability and the excellence of aquatic products and also enhance gut functions.Some information is available on nutrient immunostimulants in aquaculture applications,and this review provides information on different kinds of nutritional administration used in aquaculture to enhance positive impacts on aquatic animals’health as well as feed quality development.This review will provide theoretical references for the application of nutrient immunostimulants in aquatic feeds.

Carnobacteria in fish

Carnobacterium is a genus of Gram-positive bacteria,within family Carnobacteriaceae,and they are catalase-and oxidase-negative,non-sporing bacteria with properties such as CO_(2)and L(+)-lactic acid production from glucose,but they are not able to grow on acetate agar.They are ubiquitous lactic acid bacteria and have been isolated from both cold and temperate environments,and they are identified as components of the microbiota in the gastrointestinal(GI)tract of salmonids and several other fish species of which Carnobacterium(piscicola)maltaromaticum,Carnobacterium mobile,Carnobacterium divergens,Carnobacterium alterfunitum,and Carnobacterium inhibens are reported.During the last two decades several studies have revealed that carnobacteria can act as probiotics to promote health benefits of fish,as well as they in ex vivo studies to some extent can out-compete pathogens.In addition to beneficial effects,information is available that some carnobacteria species causing fish disease.The aim of the present review is to present an updated overview of Carnobacterium in fish,with focus on their presence in the GI tract,their use as probiotic supplement and general information on pathogenic carnobacteria.

Effects of green tea-and amla extracts on quality and melanosis of Indian white prawn(Fenneropenaeus indicus,Milne Edwards,1837)during chilled storage

Effect of ethanol extracts of green tea(Camellia sinensis L.)and amla(Phyllanthus emblica Linn)were investigated on quality and melanosis of chilled stored Indian white prawn(Fenneropenaeus indicus)during 28 days.Extracts were subjected to antioxidant assays viz.1,1-diphenyl-2-picryl hydrazyl radical reducing power methods(DPPH),total antioxidant capacity(TAC),total phenolic content(TPC)and ferric reducing antioxidant power(FRAP)to evaluate antioxidant potentiality and fourier-transform infrared spectroscopy(FT-IR)to identify organic constituents.Polyphenol oxidase(PPO)inhibition was assessed to check the efficacy of the extracts as anti-melanogenic agents.Biochemical(total volatile nitrogen,free fatty acid and peroxide values),bacteriological(aerobic counts),melanosis inhibition and sensory quality of chilled stored shrimp were addressed to investigate the efficacy of extracts as preservative and anti-melanogenic remedy.Free reducing power of green tea-and amla extracts were in a range of 28.72-65.67%and 17.38-66.95%,respectively.Phenolic content level was almost same for green tea and amla extract(2.46±0.002 and 2.51±0.036 mg GAE/gram).Total antioxidant capacity of green tea(210.33±4.63 mg EqAsc/g)was slightly higher than that of amla extracts(145.56±1.98 mg EqAsc/g).FRAP value revealed that green tea(477.49±3.25 mgE Fe(II)/g)had more ferric reducing power than amla(324.39±5.85 mgE Fe(II)/g).FT-IR analysis revealed the presence of essential organic bioactive compounds,which play an important role in reducing lipid oxidation and quality loss,and both extracts possess an encouraging PPO inhibition ability.Treatment by green tea-and amla extracts on chilled stored shrimp showed promising effects on biochemical and microbiological parameters followed by melanosis inhibition and enhanced sensory attributes.Treated Indian white prawn with green tea-and amla extract revealed significantly(P<0.05)lower value of biochemical indices and microbial load during chilled storage compared to untreated sample.

Probiotics in shellfish aquaculture

The shellfish aquaculture industry has dramatically developed during the last two decades.However,this de-velopment has,in some cases,resulted in environmental degradation,emergence of diseases and low pro-ductivity.The need for improving disease resistance,growth performance,feed efficiency,and safe aquatic production for human consumption has stimulated development and applications of probiotics in aquaculture.Probiotics used in shellfish aquaculture include genera of Lactobacillus,Enterococcus,Bacillus,Aeromonas,Alteromonas,Arthrobacter,Bifidobacterium,Clostridium,Parnibaillus,Phaeobacter,Pseudoalteromonas,Pseudomonas,Rhodosporidium,Roseobacter,Streptomyces and Vibrio.The beneficial effects of these probiotics include improved growth performance,enzymatic contribution to nutrition,inhibition of adherence and colo-nization of pathogenic bacteria in the digestive tract,modulation of the gut microbiota,and increase haema-tological parameters and immune response.The present review addressed insight into the application of probiotics in shellfish aquaculture,methods of administration,mode of actions,and their enhancing effects,and discuss research gaps and issues that merit further investigations.

Endosymbiotic pathogen-inhibitory gut bacteria in three Indian Major Carps under polyculture system: A step toward making a probiotics consortium

The gastrointestinal(GI)microbiome in fish plays significant roles in health and disease resistance.This investigation was accomplished to enumerate,characterize and identify the potential probiotic bacteria from three Indian Major Carps(IMCs),viz.,rohu(Labeo rohita),catla(Catla catla)and mrigal(Cirrhinus mrigala)using culture dependent methods.Altogether,105 pathogen-inhibitory bacteria(out of 1216 isolates)were detected from three IMCs by double layer assay.16S rRNA partial gene sequence analyses and BLAST search in the NCBI GenBank unveiled that 94.29%of the pathogen inhibitory bacteria were bacilli(99 strains)and Bacillus licheniformis by far the most common(28%).The primarily selected 27 pathogen-inhibitory strains(cumulative inhibition score≥13)produced extracellular enzymes,while 15 of them produced all the six exo-enzymes studied(amylase,protease,lipase,cellulase,phytase and xylanase).Gut stability of the strains became apparent by their ability to grow in fish mucus and tolerance to diluted bile-juice.Finally,14 strains were noticed asγ-hemolytic and susceptible to the commonly used antibiotics.Further,intra-peritoneal injection withγ-hemolytic strains did not induce any pathological signs or mortalities in fish,and thus were considered as safe.These 14γ-hemolytic isolates were represented by the genus Bacillus(13)and Stenotrophomonas(1),which might form probiotic consortia for prospective use in carp culture.