Ameiurus Research Articles

COST - BENEFIT ANALYSIS OF AFRICAN MUD CATFISH (CLARIAS GARIEPINUS, BURCHELL, 1822) FRY FED DIETARY BETAINE HYDROCHLORIDE BASED DIET

This study was carried out at the Aquatic Bio - Resources Unit, National Biotechnology Development Agency, Katsina, Katsina State. One of the objectives was to evaluate the cost - benefit of Clarias gariepinus fry fed dietary betaine hydrochloride based diet. Betaine hydrochloride was incorporated in the form of a feed additive at T0 (0.0g/100g,), T1 (0.25g/100g), T2 (0.5g/100g), T3 (0.75g/100g) and T4 (1.0g/100g) inclusion levels, respectively into 0.2 – 0.5mm size Coppens fish feeds containing 49% crude protein. Diet without betaine hydrochloride served as the control (T0), in triplicates. Diets were fed to fry (n = 1,500. 0.26±0.0g) for 28 days in 15 plastic hatchery tanks (n = 100). Fry were fed at a fixed feeding rate of 10% body weight 6 times daily between the hours of 07:00 and 23:00 at regular interval. Cost - benefit analysis was calculated for each of the diets. Mean net profit value (₦19.05), benefit cost ratio value (2.74) were better along treatments with the least incidence of cost value (₦1.67) in fry fed diet T2, while the mean net profit value of ₦11.30 was least in fry fed the control diet (T0), benefit cost ratio value (1.65) was least from both the fry fed diet T1 and diet T3, while the highest (poor) incidence of cost value of ₦2.37 was recorded from both fry fed diets T3 and T4 respectively. This study indicated that the incorporation of dietary betaine hydrochloride into C. gariepinus fry feed containing 0.5g/100g level was a profitable venture for African mud catfish breeders, considering the highest profit index value (4.37).

EFFECT OF GUTTING AND SALTING ON THE ORGANOLEPTIC QUALITIES AND PROXIMATE COMPOSITION OF SMOKED-GUTTED AND UNGUTTED, SALTED AND UNSALTED CATFISH (CLARIAS GARIEPINUS)

The effect of gutting and salting on the organoleptic qualities and proximate composition of smoked- gutted and ungutted, salted and unsalted catfish was studied. Live catfish fish of 8kg were procured from Doma Dam for the experiment. The fish sample was divided into four equal parts comprising of 2Kg each giving 4 samples. The experiment was conducted in a 2 by 2 by 2 factorial design comprising of 2-gutted and ungutted, 2-salted and unsalted and 2- catfish respectively. The fish samples were prepared separately for smoking as thus; sample 1 (gutted unsalted), sample 2 (ungutted- salted), sample 3 (gutted-unsalted) and sample 4 (ungutted - unsalted) respectively. At the initial and final stage of the experiment, each fish sample was nutritionally assessed in the laboratory so as to determine change in nutritional composition using the method of AOAC (2000). Organoleptic parameters which included texture, taste, flavour, odour and appearance were assessed from the initial stage and later fortnightly to eight weeks of storage using a 10-point hedonic scale ranging from A (Excellent) = 10; B (Good) = 8; C (Fair) = 6; D (Unsatisfactory) = 4 and E (Unacceptable) = 2 was adopted for each quality parameter. Ten judges were used for the fortnight organoleptic assessment. Results of organoleptic assessment revealed that catfish gutted-unsalted had highest mean value of 8.920.15 in texture, catfish gutted salted had highest mean value of 8.480.22 and 8.280.25 in odour and flavour respectively. Catfish ungutted-salted had highest mean value of 9.401.64 in appearance while catfish ungutted-unsalted had highest mean value of 8.920.21 in taste. The proximate composition of smoked catfish ranged each from (moisture), 3.5 14.0% (Ash), 10.0- 15.0% (crude protein), 36.0 45.9% (ether extract) 5.0 15.0% (crude fibre) 1.9 3.50% and (Nitrogen Free Extract) 8.50-30.0% respectively.

Plasma Electrolytes Response in Mud Catfish, Clarias gariepinus (Burchell 1822) exposed to Different Regimes of Salinity and pH

Introduction: Aquatic organisms, especially fish, are highly sensitive to environmental changes that can profoundly affect their physiological processes essential for survival. Physico-chemical factors such as salinity and pH exert significant influences on osmoregulation and ion balance, which are critical for maintaining cellular homeostasis in fish. Aims: This study aims to explore how varying levels of salinity and pH affect plasma electrolyte concentrations in Clarias gariepinus, focusing on potassium (K+), sodium (Na+), chloride (Cl−), and bicarbonate (HCO3−) ions. The objective is to understand the physiological responses of C. gariepinus to these environmental factors and their potential as biomarkers for assessing aquatic ecosystem health. Materials and Methods: Juvenile C. gariepinus was exposed to different salinity levels (4 ‰, 6 ‰, 8 ‰) and pH levels (4, 6, 8) over 21 days. Plasma electrolyte concentrations were measured using an SFRI ISE 6000 Electrolyte Analyser. Statistical analysis included ANOVA and DMRT to identify significant differences (p < 0.05) among experimental groups. Results: The study found significant variations in K+, Cl−, Na+, and HCO3- concentrations in C. gariepinus across different salinity and pH conditions. K+ levels decreased with increasing salinity, indicating stress-induced responses, while pH variations had less pronounced effects on K+ regulation. Cl− concentrations increased with higher salinity levels, suggesting adaptive osmoregulatory strategies. Na+ levels showed significant fluctuations across salinity and pH conditions, whereas HCO3− levels responded uniquely to changes in these parameters, demonstrating adaptive mechanisms in acid-base balance. Conclusion: This research underscores the adaptive responses of C. gariepinus to fluctuations in salinity and pH, highlighting their ability to maintain plasma electrolyte balance under varying environmental conditions. These findings contribute to understanding the ecophysiological adaptations of C. gariepinus and suggest the potential utility of plasma electrolytes as biomarkers for assessing the health of aquatic ecosystems.

Acute Toxicity and Genotoxic Responses in African Mud Catfish, Clarias gariepinus, Exposed to Biocides and Aqueous Ammonia

Acute Toxicity and Genotoxic Responses in African Mud Catfish, Clarias gariepinus, Exposed to Biocides and Aqueous Ammonia

Histopathological investigation of some facial cosmetic products mixture exposed to fingerlings of mud catfish <i>(Clarias gariepinus</i>)

Cosmetics are one of the major pollutants in the aquatic ecosystem due to the quantum of production to meet the astronomical demand of users that eventually becomes harmful to organisms. Changes in physic-chemical parameters such as potential of hydrogen (pH), Electrical conductivity (EC), Temperature (T oC) Dissolved oxygen (DO) were investigated at the beginning and after 96 hours of cosmetic exposure. This study also investigated the effects of four facial cosmetic products (Powder, foundation, concealer, and primer) histopathologically in fingerlings of Clarias gariepinus (gills) exposed to binary, trinary, and quaternary mixtures in o laboratory bioassays for 48 hours and 96 hours. The results of pH, T C, EC and DO ranged from 6.21 - 6.64, o 25.40 - 26.70 oC, 0.04 - 0.14 mS/cm, and 10.00 -12.00 mg/l respectively. The joint action toxicity evaluation of the binary, trinary, and quaternary mixtures of the cosmetics prepared based on an equitoxic ratio against the test organism was in concordance with the model of synergism. Results showed the prevalence of severe lamellar necrosis in the gills of C. gariepinus which was observed across all combinations except in the combinations of Powder + Primer as well as Powder + Foundation + Concealer + Primer. Moderate lamellar necrosis and hypertrophied epithelium were observed in fish exposed to a mixture of Powder + Foundation + Concealer. The results obtained in this study suggested that the presence of facial cosmetics in the aquatic ecosystem could be dangerous to fish and subsequently human health via biomagnification. Therefore, there is an urgent need for environmental regulators to enforce safety standards for the emission of these selected cosmetics wastes into the waterways to prevent damage to aquatic organisms and public health issues.

Inferring the allometric growth coefficient of juvenile African mud catfish, <i>Clarias gariepinus</i> (Burchell, 1822), using Bayesian and Frequentist regression models

Statistics is essential in biological and ecological scientific research. However, the default Frequentist statistics based on p-value and null hypothesis testing is often misused and misinterpreted, hence causing reproducible crises. The p-value concept deserved further examination because it has been irretrievably lost. Therefore, there is dire need for reform in the default Frequentist statistics as practiced by researchers because of the perils of p-values. Bayesian statistics, using the tools of Bayes Factors and posterior distributions derived from priors and likelihood function; rooted in Bayes’ Theorem is one of the suggested alternatives. Frequentist (least square) and Bayesian (specifying uniform Jeffreys-Zellner-Siow prior, r-scale =0.35) regression models, a standard statistical protocol in fisheries were applied to determine the allometric growth coefficient based on length (mm) and weight (g) measurements of juvenile African mud catfish, Clarias gariepinus from Epe Lagoon. The growth coefficient, b=3.20, 95% Confidence Interval [3.07, 3.34], t(96)=47.55, p<0.001 was significant with 96% explanatory power (R2=0.96).While Bayesian method, with 96% explanatory power (R2=0.96), also estimated, b=3.20, (with Credible Interval between 3.06 and 3.32). The Bayes Factor (>100) suggested the data is more plausible under the alternative model than the null model, but p-value cannot quantify evidence in support of alternative hypothesis, since p-value can only reject or fail to reject a null hypothesis. These findings suggested that juvenile C. gariepinus thrived in Epe Lagoon. Therefore, Bayesian inference is a robust substitute for Frequentist regression model in fisheries.

Monorchidism observed in a two-year-old male broodstock of Heterobranchus longifilis, Red mud catfish: a case report

Ten mature male broodstocks of Heterobranchus longifilis, Red mud catfish were purchased from a reputable farm, Arewa in Zaria for the research. A two-year-old mature male broodstock weighing 0.5kg among the ten mature male broodstocks was discovered to be a monorchid. This was observed when the broodstock was euthanized and a mid-ventral line incision of about 2-3 cm long was made using scalpel blade in order to explore its abdominal cavity for testicular exteriorization. Upon abdominal exploration, only the right testis was present but the right testis was completely absent without remnant. The left testis present was observed to be twisted in the middle along its vertical axis. The morphometric and milt parameters of the right testis present were determined as: testicular length (4.2 cm), testicular weight (1.05 g), milt volume (0.12ml), sperm motility (75%) and sperm concentration (377 x 106/ ml). Keywords: Broodstocks, Exteriorization, Monorchidism, Morphometric and Testis

Acceptability of Korean Fish Cake Made from Patin Fish

Catfish is one of the many fish species cultivated in Indonesia so that the number increases rapidly every year, but this is not in line with the diversity of processed catfish products. One way to increase the diversity of processed catfish is by diversifying the product into Korean fish cake. This study aims to develop a formula and determine the acceptability of Korean fish cake made from catfish. This research was conducted by experimental method. Based on the results of the recipe analysis, the starting recipe was produced which was then tested 3 times. From the QDA test conducted by 3 expert panelists, the best sample was chosen, namely KFCIP 3 with a composition of catfish 29.9%, squid 29.9%, shrimp 14.9%, wheat flour 3.7%, potato starch 5, 3%, garlic 3.2%, onion 4.3%, egg white, 4.3%, salt 1.9%, sugar 2.2% and white pepper 0.4%. Furthermore, organoleptic tests were carried out to determine the acceptability of 30 untrained panelists. From the results of the research and analysis carried out, it shows that the composition of taste, aroma, color, texture has acceptance with the "very favorable" category. Overall, Korean catfish fish cake has an acceptance category of "very liked". This research also produced a Korean fish cake formulation made from catfish which was positively received by consumers.

Effects of different latency periods on fingerlings production using Clarias gariepinus (African mud catfish)

The research was carried out in the Fish Hatchery of the Department of Fisheries, Teaching and Research Farm, Modibbo Adama University. Clarias gariepinus belongs to the family Clariidae. The latency period had been demonstrated to affect fingerling production in C. gariepinus. Fifteen (15) gravid broodstock females weighing 367 to 1000 g and males of 800 to 1200 g were used at different latency periods of 9, 11, 13, 15 and 17 hours designated D1, D2, D3, D4 and D5. Three replicates of the female broodstock were injected with 0.5 ml Ovaprim for each latency period. The number of 1 g of eggs from each treatment was D1 (847), D2 (705), D3 (847), D4 (692) and D5 (847). Percentage fertilization was highest in 11, 13 and 15 hours latency periods (99.19%, 97.66% and 99.33%) respectively; and were significantly different (p<0.05). Percentage hatchability was highest in 13 hours latency period 63.73% and the least was in 17 hours latency period (1.99%). Unhatched eggs were higher in a latency period of 17 hours (5612). Number of hatchlings was highest in latency period of 13 hours. The highest percentage survival was in a latency period of 11 hours. Any attempt to improve fingerling production in C. gariepinus should consider the effect of the latency period in relation to weight. After three weeks of indoor incubation, a latency period of 15 hours showed better weight gain than others. The best latency period achieved in this study was 11 hours.

Glycogen in retinal horizontal cells of the African mud catfish Clarias gariepinus (Burchell, 1822) and its physiological significance

This paper reports on glycogen store in the retinal horizontal cells (HC) of the African mud catfish Clarias gariepinus, as seen by histochemical reaction with periodic acid Schiff (PAS) and transmission electron microscopy in light- as well as dark-adapted state. Glycogen is abundant in the large somata and less in their axons, characterised ultrastructurally by many microtubules and extensive gap junctions interconnecting them. There was no apparent difference in glycogen content in HC somata between light- and dark adaptation, but the axons clearly showed absence of glycogen in dark condition. The HC somata (presynaptic) make synapses with dendrites in the outer plexiform layer. Müller cell inner processes, which contain more densely packed glycogen, invest the HC. Other cells of the inner nuclear layer do not show any appreciable content of glycogen. Rods, but not cones, contain abundant glycogen in their inner segments and synaptic terminals. It is likely that glycogen is used as energy substrate in hypoxia for this species that dwell muddy aquatic environment with low oxygen content. They appear to have high energy demand, and a high glycogen content in HC could act as a ready source to fulfil physiological processes, like microtubule-based transport of cargo from the large somata to axons and the maintenance of electrical activities across the gap junctions between the axonal processes. It is also likely that they can supplement glucose to the neighbouring inner nuclear layer neurons, which are clearly devoid of glycogen.

The Effect of Using Catfish and Cork Fish on the Quality of Fish Fingers

The needs of today's society are the availability of food that is ready to cook and ready to eat. One type of food innovation is frozen food such as fish finger.Fish finger is a processed fish product made from pieces (fish fillets) or fish meat or surimi which are then given spices, coated with batter flour (a mixture of several flours that function as coating materials and adhesives) and breadcrumbs (bread flour) as an outer layer which is then fried half-baked and frozen.This study aims to analyze the effect of using catfish and cork fish on the quality of the shape, color, texture, aroma and taste of fish finger. This type of research is a pure experiment (true experiment), using a completely randomized design (RAL) with 3 repetitions. The research was conducted in the Catering Workshop of the Department of Family Welfare Science, Faculty of Tourism. This research was conducted in January 2023 with three repetitions. The type of data used is primary data sourced directly from 3 expert panelists in the organoleptic test. Based on the results of the organoleptic test, it shows that there is no significant difference in the quality of fish fingers using catfish (X1) and cork fish (X2). The best overall score is the quality of uniform shape (X2) 3. The quality of the beam shape (X2) 3.22. Golden yellow color quality (X2) 3.89. Fragrant aroma quality (X2) 3.78. The quality of chewy texture (X2) is 3.44. Savory taste quality (X2) 3.44. Based on the data obtained, it can be observed that the quality of cork fish fingers is better than catfish fish fingers.

Epidemiology and economic impact of disease-related losses on commercial catfish farms: A seven-year case study from Alabama, USA

The objectives of this study were to determine statewide production losses caused by diseases, identify the most incident catfish diseases affecting Alabama (AL) farm-raised catfish production in freshwater ponds and their annual pattern, and determine disease-related economic impacts. The Alabama Fish Farming Center (AFFC) conducted seven annual retrospective questionnaire surveys of AL catfish farmers since 2015 to assess the epidemiological situation of farm-raised catfish fish diseases and their economic impacts. Across the study (2015–2021), the annual number of survey respondents ranged from 64 to 74, with a total of 482 respondents. The yearly survey response rate ranged from 95.6 to 100% (mean: 98.2%). The annual survey coverage area ranged from 6410 to 7006 ha/year. About 97% of survey coverage area reported fish losses caused by a disease. Fish diseases resulted in the loss of 9 million fish/year (2.9 million kg/year; 436.7 kg/ha/year). Bacterial diseases resulted in >83% of catfish disease losses (>5 times losses to non-bacterial causes). The most incident statewide catfish disease was hypervirulent Aeromonas hydrophila (225 kg/ha/year), followed by columnaris (140 kg/ha/year), followed by Edwardsiella (52 kg/ha/year). The temporal epidemiological analysis results indicate that annual trends of proliferative gill disease and Bolbophorus disease were correlated with prolonged precipitation periods and total quantity of rainfall, respectively. Economic losses caused by fish losses to bacterial diseases, non-bacterial diseases, production losses due to reduced feeding during outbreaks, and expenditures associated with catfish diseases were responsible for 54.5%, 10.8%, 22.0%, and 12.7% of total direct economic impacts attributed to AL farm-raised catfish industry, respectively. Total disease-related financial losses in west AL were 11.1 million USD/year (1651 USD/ha/year), representing about 9.5% of food-size catfish sales in AL. The present study provides the first extensive assessment of epidemiology and health economics of farm-raised catfish disease in the freshwater pond environment for a substantial duration. More studies focusing on disease losses at the county- and farm-level would provide useful information regarding the spatial epidemiology of diseases and their underlying risk factors.

EFFECTS OF TWO BIO-PRESERVATIVES ON KEEPING QUALITY OF AFRICAN MUD CATFISH, CLARIAS GARIEPINUS

The study evaluated the effects of two commonly used household bio-preservatives, Sodium chloride and Ascorbic acid on the proximate and microbial compositions of smoked African mud catfish, Clariasgariepinus during a six weeks’ storage period. Fresh fish samples weighing 450-500g each obtained from the fish farm of the Department of Animal and Environmental Biology, Adekunle Ajasin University, Akungba-Akoko, Nigeria were degutted and cleaned with water. A group of fresh fish sample was soaked in a mixture of 25% NaCl and 1% ascorbic acid for 1hour and 30min and then prepared for smoking while another untreated batch served as the control. The samples were smoked dried in the smoking kiln at 80oC for 12hrs, cooled and packed in open and air tight containers in the laboratory for six weeks. The samples were then analysed for pH, proximate and microbial compositions at zero, two, four and six weeks respectively following standard procedures. There were significant differences (p≤0.05) between the treated and untreated groups. Pre-treatment of fish samples with a mixture of 25% NaCl and 1% ascorbic acid prior to smoking enhanced the keeping quality and stability of fish during storage.

Effectiveness of particle size of selected plant materials as protectants of stored Clarias gariepinus against Dermestes maculatus infestation

The focus of this study was to determine the efficacy of the different particle sizes of the powder of three plant materials, African Nut-meg (Monodora myristica), Black pepper (Piper guineense) and dry bud of Cloves (Eugenia aromatica) in the control of Dermestes maculatus infestation on stored dried African mud catfish, Clarias gariepinus. Each plant material was pulverized, sieved into 0.5 mm and 0.4 mm particle-sizes, rubbed at 5 g of powder onto the body of 55 g dried fish and placed in Kilner jar in triplicates. The weight loss, adult / larvae emergence and adult mortality of treated fish were determined. The results showed that 0.4 mm particle size of the powder of P. guineense and E. aromatica prevented the infestation of D. maculatus as demonstrated by low fish weight loss, low level of adult / larvae emergence and high mean value of adult insect mortality. Higher number of larvae emergence and weight losses were recorded in the fish exposed to 0.5 mm of each plant powder and 0.4 mm of M. myristica. The study revealed that stored catfish could be treated with smooth particle sizes of Piper guineense and Eugenia aromatica, and can significantly serve as protectants of smoked C. gariepinus against Dermestes maculatus infestation.

Acute and sub-lethal toxicity in African mud catfish (Clarias gariepinus, Burchell, 1822) exposed to some pesticides

Pesticides from agricultural run-off pose a severe threat to non-target organisms, such as fishes. This study was carried out to evaluate acute toxicity and histological and genotoxic effects (erythrocytic nuclear abnormalities) of lethal and sub-lethal concentrations of three commonly used pesticides: Atrazine, Butachlor and Glyphosate on the African mud catfish (Clarias gariepinus). Fishes were exposed to the pesticides for 96h periods to determine their LC50 and the sub-lethal effect at various concentrations (1/10th, 1/100th , 1/1000th 96h LC50) over 28 days. The 96h LC50 values were 7.63mg/l, 0.7mg/l and 15.97mg/l for atrazine, butachlor and glyphosate, respectively. Histological sections of the liver of C. gariepinus exposed to the three pesticides showed mild vascular congestion but no necrosis in the tissue. There was a significant (p<0.5) dose-dependent increase in micronuclei and nuclear abnormalities in the erythrocytes of exposed C. gariepinus compared to the control by 28 days. The study confirmed that C. gariepinus are at risk of adverse effects from exposure to pesticides. Discharge of agricultural run-off around water bodies should be prevented or prohibited to avoid adverse effects on aquatic life.

Ammonia reduction by different thickness coral shard filter in cultivation of Catfish (Pangasius sp)

Catfish (Pangasius sp.) is a consumption fish that is quite popular and has a selling value. Fish have tolerance standards for water quantity and quality, so water as a living medium should be managed in aquaculture. One of the water quality parameters that affect the survival of cultured fish is ammonia (NH₃). Ammonia at high concentrations can adversely affect fish, such as reducing the ability of the blood to carry oxygen, damage to body tissues, fish susceptible to disease, inhibiting growth and death. This research aimed to determine the thickness of the coral shard filter, which effectively reduces ammonia (NH₃) in catfish culture. This research was conducted at the Dry Fisheries Laboratory, Faculty of Animal Husbandry, Fisheries and Marine Science, University of Nusa Cendana. The research started from February 2022 - April 2022. The implementation of this research used a Completely Randomized Design (CRD) with 4 treatments and 3 replications, namely: without coral shards filter (A), treatment using a coral shard filter with a thickness of 5 cm (B), coral shard filter with a thickness of 10 cm (C) and coral shard filter with a thickness of 15 cm (D). Results show that filter coral shards treatment with 5 cm thickness can reduce the concentration of ammonia in the cultivation of fish catfish from a score beginning research of 0.02 mg/L to 0.018 mg/L in the end research.

Efficacy Assessment of Brewery Wastewater Treatment Practice using Physico-chemical Characterization and Toxicity Markers in African Mud Catfish (Clarias gariepinus Burchell, 1822) and African Brackish Water Shrimp (Palaemonetes africanus Balss, 1916)

Industrial activities and urbanization in developing countries have gradually led to the deterioration of the environment in recent years. Large quantities of wastewater effluent are inadequately treated or untreated before discharge into receiving waterbodies, resulting in environmental health concerns. Thus, this study investigated the efficacy of a brewery wastewater treatment system in Lagos by assessing the physicochemical characteristics, acute toxicity, and oxidative stress induction capabilities of the influent (untreated) and effluent (treated) on African mud catfish, Clarias, gariepinus and brackish water Shrimp, Palaemonetes africanus. The test organisms were acutely and sub-lethally exposed to predetermined concentrations of treated and untreated brewery wastewater. Results from the physicochemical assessment of the respective wastewater indicated that the treatment process was relatively effective in improving acidity levels (80.0% reduction), suspended solids (88.0% reduction), total nitrogen concentration (77.0% reduction), chemical oxygen demand (24.05% reduction), and biological oxygen demand (30.0% reduction), while nickel and cobalt concentrations reduced by 50%. Also, there was improvement of dissolved oxygen by about 250%. The 96 h LC50 value of the Catfishes and shrimps exposed to treated wastewater were 12.926 ml/L and 1.095 ml/L respectively compared to and 10.371 mg/L and 0.061 mg/L for the untreated wastewater, indicating an improvement factor of 1.23 and 17.95 for both species, correspondingly. Inhibition of the levels of activities of anti-oxidative enzymes (Reduced glutathione GSH, Superoxide dismutase SOD, and Catalase CAT) and increased lipid peroxidation damage (Malondialdehyde MDA) were recorded in all treatments for both test species, relative to the unexposed control groups. The enzymes however did not show significant trend with respect to the wastewater treatment status. Overall, it can be concluded that the wastewater treatment improved the effluent quality and such a process should be encouraged and enforced to ensure sustainable use of our water bodies.

Expression of immune-related gene from African mud catfish Clarias gariepinus reared in bioflocs systems after Aeromonas hydrophilia infection

The influence of various carbon sources as bioflocs on relative immunological gene expression, haematology, growth, and microbial community in Clarias gariepinus juvenile culture is investigated in this study. The bioflocs groups (four) were created by daily supplementation with four carbon sources (cassava peel, tapioca, wheat offal, and brewery waste) with a carbon-nitrogen ratio of 20 and the control without carbon addition. The juvenile Clarias gariepinus (8.16 ± 0.2 g) was stocked into each bioflocs system and reared for 72 days. The results revealed that the water quality parameter and survival rate differed significantly across the treatments. The microbial community revealed that there were differences in bacterial intensity and diversity among the various culture systems. The haematological parameters between the treatments showed a significant difference p<0.05 in the challenged test. qRT-PCR was used to assess immune-related gene expression, and four immune genes (IL-10, TNF-α, TGF-β, IL-1β) were shown to be increased. As a result, the bioflocs system can be considered to boost innate immunity and immune-related gene expression. Overall, this research found that using bioflocs technology can help with immunostimulation, and that the effect is independent of the organic carbon utilised to keep the fish alive.

Bacteria associated with smoked catfish sold at Bida Modern market, Northcentral Nigeria

In Nigeria, Fish serves as the affordable source of animal protein, where most individuals consume smoke fish as a food delicacy. This study was carried out to identify and ascertain the bacteria contamination of smoked catfish sold at Bida modern market in Northcentral Nigeria. A total of Fifty (50) samples of smoked Catfish were purchased from fish traders in the market. The fish samples were analyzed using standard bacteria techniques and procedures. The result shows mean bacterial loads of 184 colonies with a population of 1.84 × 106 Cfu/g. A total of seven (7) species of bacteria were isolated from the sample. The bacteria species consist of four (4) gram-positive bacteria and three (3) gram-negative bacteria. The bacteria isolate encountered in this study were Staphylococcus aureus, Staphylococcus epidermidis, Bacillus sp., Micrococcus sp., Escherichia coli, Salmonella sp. and Proteus mirabilis. The study revealed that smoked catfish sold in Bida modern market are contaminated by different groups of bacteria, which could be due to the unhygienic nature of the market and the fish handlers. The presence and abundance of this groups of bacteria in smoked catfish fish could result into food poisoning, which is a matter of public health concern.

Length-Weight Relationship and Condition Factor of African Mud Catfish (Clarias gariepinus (Burchell 1822) and Tilapia (Oreochromis nilotica Linnaeus 1758) in Orashi River of Ogba/Egbema/Ndoni Lga of Rivers State, Nigeria

Length-weight relationship and condition factor are important in fishery assessment studies since it provide information about the growth of the fish, its general wellbeing and fitness in aquatic habitat. LWRs for 2 fish species –Clarias gariepinus (Burchell 1822) and Oreochromis nilotica (Linnaeus 1758) collected from Orashi River were established and their growth condition was evaluated. The study was carried out from September 2019 to August 2020. The biometric measurement (length/weight) shows that the weight of the fish increased in proportion to its length as indicated by the slope (b) of the relationship. The mean value shows strong relationship because coefficient of determination (R2) is >0.5 and range from 0.795-0.985. Higher values of both length and weight were recorded for Catfish over Tilapia. The results indicated that almost all the fish sampled exhibited a positive allometric growth and trended to grow bigger. All relationship were statistically significant (p=0.05). The mean Fulton’s condition factor (K) of the fish range from Catfish (1.24-1.80) and Tilapia (1.5-3.7) in the 5 stations sampled. The result showed that Tilapia had a high mean range and therefore was in better conditions than the Catfish. This gives information on the food supply, timing and duration of breeding cycle. The indices may also be used in the general assessment of the “well being” of a fish [1]. Multiple comparison tests using Turkey Kramer showed that the condition factor of Catfish from Okwuzi (station 1) was significantly different from that of Ndoni and Omoku but Ebocha and Obrikom was not significantly different from each other. With regards to seasonal variation, dry season recorded higher values than rainy season.