Nigerian Journal of Fisheries and Aquaculture

Digital Platforms and Mobile Technology in Aquaculture Communication Among Fish Farmers in Kogi State, Nigeria

Mundi N. E. — 2024-09-22

The study examined how fish farmers in Kogi State, Nigeria, utilized communication channels. Two hundred fish farmers were chosen using stratified and simple random sampling techniques. One hundred and eighty-seven valid questionnaires were collected and analyzed using descriptive statistics. The findings showed that 77.1% of fish farmers received information on aquacultural innovations through the Train-and-Visit system. Most respondents (63.6%) preferred this system because of its accessibility (56.5%), ease of understanding (24.0%), and cost-effectiveness (6.9%). However, challenges such as irregular visits of extension agents, insufficient training, inconsistent information, and delayed communication were reported. For radio and television, limitations included the lack of direct interaction with extension agents, language barriers, high equipment costs, and network service issues. Additionally, 63.6% of respondents reported the unavailability of printed materials in their localities, while 31.6% were illiterate, and 4.8% faced language barriers in understanding English. The study recommends distributing extension guides in local languages and equipping extension agents with improved communication tools like mobile platforms to better meet the needs of fish farmers.

Changes in Hematological, Serum Biochemical, and Organosomatic Index of Nile Tilapia Oreochromis niloticus (Linnaeus, 1758) Fed Unprocessed and Processed Roselle (Hibiscus sabdariffa) Seed Meal

Yunusa A. — 2024-09-30

The fish used for the experiment were fingerlings of Nile tilapia with a mean weight of 0.60g procured from the Federal Department of Fisheries fish farm in Kaduna. The experiment involved growth trials using five diets comprising unprocessed, boiled, fermented, soaked, and sprouted Hibiscus sabdariffa seed meal-based diet for seven months. Blood samples were collected from the caudal vein of the fish for hematological indices. The results indicated that fermented roselle showed higher (0.99mg/l) hemoglobin erythrocyte (8.95mg/l), and hematocrit (31.50%) levels. The unprocessed roselle-based had the lowest values of 0.74mg/l, 7.4mg/l, and 29.4% for erythrocyte count, hemoglobin, and hematocrit, respectively. Liver and spleen enlargement occurred in the fish fed unprocessed roselle, indicative of hepatocyte necrosis and chronic inflammatory response. Using unprocessed roselle seed meal in the diet of O. niloticus adversely affected its blood parameters and organ health, suggesting potential physiological stress.

Toxicity of the Herbicide 2, 4-D Dimethyl Amine Salt on Behavioral, Growth and Hematology of Clarias gariepinus (Burchell, 1822) Fingerlings

Hamisu Y. — 2024-09-29

The study aimed to determine the toxicological impacts of the herbicide 2, 4-D Dimethyl amine salt on Clarias gariepinus fingerlings. After a series of range finding tests, the fishes were exposed to lethal concentrations of 0.00, 1.34, 1.42, 14.8, 1.54, and 1.60ml/L for 96 hours as well as sub-lethal concentrations of 0.00, 0.069, 0.138 and 0.276ml/L of 2, 4-D Dimethyl amine salt for 8 weeks in a renewal bioassay. The value of 96 hours LC₅₀ was 1.385ml/L. Respiratory disturbance, erratic swimming, loss of equilibrium, lethargy, and sudden fish death were observed in 96hrs of exposed fish, and these varied greatly with differences in concentration of the toxicant, with a trend of significant (p<0.05) increase in mortality with increasing concentrations. The physicochemical parameters obtained before and after the experiment were within tolerable limits. The growth rates were significantly (p<0.05) reduced in fish exposed to sub-lethal concentrations of the herbicide 2, 4-D Dimethyl amine salt. The toxicant led to significant changes (p<0.05) in hematological parameters. Mean red blood cells and packed cell volume reduced with an increase in the concentration of the toxicant, while other parameters, such as white blood cells increased proportionally to the toxicant concentration. The lethal and sub-lethal exposure of Clarias gariepinus fingerlings to 2, 4 D dimethyl amine salt with values of 1.6 ml/L, 0.138ml/L 0.276 ml/L indicate significant changes in hematological parameters of acute, sublethal respectively.

Evaluation of Garlic (Allium sativum) Supplemented Diets on Growth and Hematological Parameters of Heterobranchus longifilis (Valenciennes, 1840)

Ago A. N. — 2024-09-29

Natural feed additives are efficient in reducing the need for antibiotics therefore, nutritionists are using plant-based feed additives such as garlic. This study evaluated the effect of garlic on the growth and hematological parameters of H. longifilis juveniles in a 56-day feed trial. H. longifilis juveniles (57.80±26.7g) were divided into fifteen circular tanks (60 liters capacity) and stocked 10 fish per tank in three replicates. Five experimental diets were formulated, each containing varying amounts of garlic powder: 0.00 (control) 0.01g/kg, 0.015, 0.02, and 0.025g/kg designated as G0, G1, G2, G3, and G4, respectively. Fish were fed 2% body weight twice daily. The results revealed that fish fed 0.015g/kg of garlic gave a significantly (P<0.05) higher mean weight gain of 8.39g±0.84 while fish fed control gave the lowest mean weight gain of 1.3g±0.00. The specific growth rate and mean feed intake followed the same pattern but showed no significant difference (P>0.05). The food conversion ratio was relatively high in the fish fed the control group and lowest in fish fed G2 diet. The Hematological parameters of garlic-supplemented diets showed a general decrease except for Total white blood cells. The Packed cell volume, Hemoglobin, and Total red blood cell values were significantly (P<0.05) higher in the control than in fish fed with garlic-supplemented diets. The Total white blood cells showed a significant (P<0.05) increase in fish fed with a garlic-supplemented diet. This indicates garlic inclusion in the diet of H. longifilis should be minimal and 0.015g/kg is recommended.

Hematological and Biochemical Response of Clarias gariepinus Fed Pyxichephalus Adspersus Meal as Fishmeal Replacement Fortified with Curcuma Longa L. as an Additive

Udeh L.O. — 2024-09-30

Studies on the combination effect of Pyxicephalus adspersus meal as fishmeal replacement and Curcuma longa as an additive on the Clarias gariepinus are scarce. This feeding trial was conducted to ascertain the impact of incorporating various inclusion levels of Pyxicephalus adspersus and Curcuma longa as an additive on specific hematological and biochemical parameters of Clarias gariepinus juveniles. Six iso-nitrogenous and iso-caloric diets of approximately 44% crude protein were compounded at C1 (control) basal diet of 100% fishmeal, T1 (basal diet + Curcuma longa), T2 (basal diet + 25% Pyxicephalus adspersus meal, Curcuma longa), T3 (basal diet + 50% Pyxicephalus adspersus meal, Curcuma longa), T4 (basal diet + 75% Pyxicephalus adspersus meal, Curcuma longa), and T5 (basal diet + 100% Pyxicephalus adspersus meal, Curcuma longa). A total of 180 juveniles of Clarias gariepinus weighing approximately 34.20 g were allotted into twelve rectangular plastic tanks and fed twice daily at 5% body weight for 24 weeks. The results showed that fish fed a 25% Pyxicephalus adspersus meal and a Curcuma longa basal diet had the best weight gain of 265.6 g. Blood samples of the fish were randomly collected to determine the blood indices such as white blood cell, red blood cell, hemoglobin, mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration, and Alanine transaminase, Aspartate transaminase, Alkaline phosphatase using standard methods. Mean corpuscular volume and hematocrit were significantly different (p < 0.05). This research revealed that a combination of Pyxicephalus adspersus and Curcuma longa as an additive altered some blood parameters of Clarias gariepinus without adverse effects.

Molecular Detection and Characterization of Tetracycline-Resistant Genes and their Sensitivity to Synthetic Antibiotics in Bacteria Isolated from Chrysichthys nigrodigitatus in Ogun River, Nigeria

Adekunle T. A. — 2024-09-29

In this study, bacteria were isolated from the skin, gills, and intestines of Chrysichthys nigrodigitatus collected from Ogun River, and their resistance to tetracycline and sensitivity to various synthetic antibiotics were investigated. Samples were cultured on selective media, and bacterial isolates were identified through biochemical and molecular analyses. A total of 45 samples, including skin, gill, and intestine tissues, were microbiologically analyzed. The mean values of body weight, total length, and standard length of the fish samples were 147.99±66.41g, 26.55±5.55cm, and 20.05±4.13cm, respectively. Physical and chemical parameters of the river during the study included a water temperature of 29.0°C, pH of 7.8, dissolved oxygen at 4.9 mg/l, and ammonia at 2.3 µg/dL. The total mean bacterial count was highest in the intestine (1.36 ± 0.27 x 10⁵ CFU/g), followed by the gill (1.06 ± 0.20 x 10⁵ CFU/g) and the skin (0.77 ± 0.21 x 10⁵ CFU/g). Bacterial growth was observed on eosin methylene blue and Salmonella-Shigella Agar. One hundred and thirty-five (135) bacterial isolates were identified, including Escherichia coli (15.3%), Staphylococcus aureus (22.2%), Bacillus spp. (25.2%), Salmonella spp. (22.2%), and Pseudomonas aeruginosa (9.6%). Molecular analysis confirmed the presence of tetracycline resistance genes in some isolates, highlighting the potential public health risk posed by antibiotic-resistant bacteria in aquaculture. The findings suggest better management of antibiotic use in aquaculture to mitigate the development and spread of antibiotic resistance in aquatic environments.

Survey of Gastrointestinal Parasites in Clarias gariepinus (Burchell, 1822) and Coptodon zilli (Gervais, 1848) of Wasai Reservoir, Kano, Nigeria

Haruna A. — 2024-09-29

The study aimed to investigate the prevalence and intensity of parasitic infections in Clarias gariepinus and Coptodon zilli in Wasai Reservoir. The study was conducted from January 2019 to June 2020, spanning 18 months. Standard techniques for parasitology were employed in the study. Fish samples were dissected and examined, and parasites were removed, identified, and counted. The results revealed that out of 477 C. gariepinus examined, 59.03% were infected with 21 intestinal helminths, including Cestodes, Trematodes, and Nematodes. In contrast, 331 (40.97%) were recorded in C. zilli. Prevalence of infection was higher in males 258 (76%) than in females 219 (24%), which did not differ significantly between sex and prevalence rate in C. gariepinus (x² = 0.723, d.f 1 (0.395). Among C. zilli, the prevalence of sex revealed a higher 234 (87.6%) males than in females 97 (22.4%), where the difference was not statistically different in infection rate (x² = 2.001 d.f = 1 (0.98%). Six (6) fish parasite species were isolated, identified, and recorded as Trichodinas spp., Diplosbotrium latum. Chilodenella spp., P. chlaradae., Emeria spp., Cestode larvae, and procammalanus spp. The most prevalent parasites recovered were Chilodenella sp., with a 14.0% number of infections, an intensity of infection of 1.09, and an index of infection of 14.1%. This study showed a considerable health risk to consumers due to parasitic infection. Therefore, periodic parasitological investigations should be carried out to curtail the potential dangers to future generations along the reservoir.

Evaluation of Camel Testes for Masculinisation of the Nile Tilapia (Oreochromis niloticus, Linnaeus, 1758)

Mohammed Z. B. — 2024-09-29

Nile tilapia is among the leading farmed fish species around the world. They are highly prolific; hence, they congest fish ponds. The use of methyltestosterone (MT) to produce sterile, all-male tilapia has been established. The MT is very expensive, not very common, and has been publicly criticised due to its health and environmental implications. The efficacy of camel testes for the masculinisation of Nile Tilapia was investigated to evaluate its potential for the production of all-male Oreochromis niloticus. Various concentrations (0, 25, 50, 75, and 100%) of camel testes per kilogram of feed were incorporated into a 40% crude protein diet and fed to 7-day-old fry for 40 days indoors. At the end of 40 days of feeding with the camel testis-based diet, ninety (90) fish were stocked in a 2 x 2 x 1.2 m net hapa installed in 7 x 5 x 1.2 m polyethylene-lined fish ponds based on their treatments. They were further reared for another 30 days for sex identification. The results show that fry fed with 100% camel testes produced a higher (91.11%) male population, followed by (87.60%) fry treated with a 75% camel-based diet. No significant variation (P>0.05) was observed between the number of males in fish fed a 100% camel-based diet compared to those fed 75%. Camel testes demonstrated greater potential for masculinisation in Oreochromis niloticus.