Toxicity of promethazine hydrochloride (Phenergan) to Clarias gariepinus fingerlings

The acute toxicity of promethazine hydrochloride (phenergan) to Clarias gariepinus fingerlings was conducted using static bioassay under laboratory conditions. The 96h LC50 was determined as 172.5 mg/1. Mean mortality was 5, 10, 20, 50, 100% in the concentration of 69, 103.5, 138.0, 172.5 and 207 mg/1 respectively, while there was no mortality in the control treatment. There were significant differences (P<0.05) on the effect of concentration, the higher the mortality of C. gariepinus fingerlings while toxicity of phenergan increased with duration of exposure. C. gariepinus showed increased hyperactivities, cell deformation, lesions and necrosis during the period of exposure. The physicochemical parameters also showed a slight increase as the concentration increased

Fisheries and aquaculture development in Nigeria: an appraisal

Nigeria has a coastline of 853km and over 14 million hectares of inland waters and thus owns significant fisheries. The contribution of fisheries to the Nigerian economy is significant in terms of supply of high quality dietary protein, income generation, creation of employment and enhanced inflow of foreign exchange earnings through shrimp export. However, due over-exploitation of the natural resources, by-catch and discard problem, inadequate infrastructure and social amenities development, inadequate supply of fish feed, fish seeds and slow adoption of new technology and management strategies etc. The domestic fish production (0.55 million tons) has fallen short of the demand (1.5million metric tons). Aquaculture development is the solution to the unpredictable production through capture or artisanal/industrial fisheries

Acute toxicity of industrial effluents from Agbara environs of Ologe Lagoon on early life stages of African catfish Clarias gariepinus

The acute toxic effect of industrial effluents from Agbara Industrial environs of Ologe lagoon was investigated in a static renewable lethal bioassay using fingerlings and Juveniles of African catfish (Clarias gariepinus). Twenty (20) pieces of the fingerlings were stocked per tank and each treatment was in triplicate. Physico-chemical parameters: temperature, pH, Dissolved Oxygen, DO and conductivity in treatment tanks were monitored for 96 hours. Behavioural responses were studied; mortality data recorded, and histopathological analysis was also done. Except for dissolved oxygen, other physico-chemical parameters monitored did not show significant differences (p>0.05). The lethal bioassay showed that as the concentration of effluent increased, more mortality was recorded; but as the time of exposure increased, mortality reduced. The LC50 obtained at all the different time intervals for C. gariepinus fingerlings in 24,48, 72 and 96 hrs were: 69.45,46.39, 40.81 and 34.03(%). While in juveniles, the values were: 64.52,49.21, 32.50, and 19.63(%) respectively. Abnormal behaviour was observed; they showed repeated darting movement within an hour of introduction, darkening in the eye and on the skin, haemorrhage in the gills, spiral swimming and death. Histopathological examination of the gills and liver of the fishes showed lesions which increased progressively with increasing level of toxicants. Observed changes in the gills were mainly: epithelial lifting, swollen lamellae, necrosis and mass degeneration, fatty and vacuolar degeneration, loss of lamellae and marked disorganization in gill structure and arrangement. In the liver, there were vacoulation, portal congestions, pancreatic necrosis, fatty degeneration and severe disruption of the hepatic cord. Fishes in the control treatments showed no visible lesions throughout the experiments. This information confirms that histopathological alterations are good biomarkers for toxic impact assessment of industrial effluent on fish. Therefore, an indiscriminate discharge of this effluent to surrounding water should be discouraged

Fertilization, hatchability, survival and larval biometry in interspecific and intergeneric hybrids of Clariid catfishes

Interspecific and intergeneric hybridization studies were carried out in H. longifilis, C. gariepinus and C. anguillaris under controlled hatchery conditions to estimate their aquaculture potential in terms of fertilizability, hatchability and survival. Fertilization rate in all the nine genetic crosses ranges from 60-87.5%, the fertilization rates of the parentals being significantly higher(P<0.05) with highest value of 87.5% obtained in C. gariepinus. The intergeneric hybrids had the lowest rate of fertilization. Hatchability ranges between 75- 88.1 %, with the parental C. anguillaris being slightly significantly higher than the other genetic combinations. C. anguillaris x H. longifilis I had the lowest hatchability and there was no significant difference (P<0.05) in percent hatching among the the interspecific hybrids. The survival of all the nine genetic crosses from hatching up to the end of the two weeks indoor rearing period ranges between 78-89%, which wasn't significantly different among the interspecific and intergeneric hybrids. C. anguillaris and C. gariepinus had the highest percent survival which was significantly different from all the other mating combinations. The intergeneric hybrid larval had significantly greater (P<0.05) length in comparison to the interspecific hybrids. H. longifilis and the hybrids produced from its eggs had greater body weight than that of C. gariepinus and C. anguillari

Haematological profile of blood of African catfish (Clarias gariepinus, Burchell 1822) fed sunflower and sesame meal based diets

The effect of substituting soybean meal with raw sunflower and sesame seed meal was evaluated using haematological indices of Clarias gariepinus fed the diets containing sunflower and sesame seed meal. Seven isonitrogeneous and isocaloric diets containing sunflower and sesame seed meal replacing soybean meal at a rate of 15, 30 and 45% were prepared. A diet without replacement of soybean meal served as control. The result of fish fed test diets showed significant (P0.05) in the fish fed control diet and test diets with respect to MCH, MCHC, ESr, Neutrophil, Monocytes, Eusinophils and Lymphocytes. Hence it can be concluded that the haemotological parameter of Clarias gariepinus is not significantly (P>0.05) changed with increase dietary inclusion of raw sunflower and sesame seed meal

Potentials of some medicinal plants as fertility enhancing agents in fish

The potentials of some medicinal plants that enhance fertility in animals were highlighted. Though, these medicinal plants can be used for other purposes but this paper focused on the fertility potential of the plants on animals. Some of the plants such as date palm (Phoenix dactylifera), wild yam (Discorea villosa) and Focus capensis had been discovered to enhance fertility in rats, monkey and poultry. Therefore if these medicinal plants could work on rats and poultry for fertility enhancement, the plants could as well be tried on fish so as to enhance the fecundity and sperm production in female and male brooders which will eventually lead to increase in fish seeds production. However, research is on going on the use of some medicinal plants to enhance fecundity and sperm production in male and female brooders in order to increase fingerlings production which would subsequently lead to increase in fish production

Apparent nutrient digesibility coefficient of sunflower and sesame seed meal in Clarias gariepinus (Burchell 1822) fingerlings

The apparent digestibility coefficient of raw sunflower (Helianthus annus). and sesame (Sesamum indicum) seedmeal by Clariid catfish (Clarias gariepinus) fingerlings was evaluated at 15,30 and 45% levels of replacement respectively using soybean meal based diets as control diet. There was significant difference (p0.05) in apparent lipid and fibre digestibilities of fish fed control diet and test diets RSF15 and RSM1

Toxicity of African locust bean effluent on Oreochromis niloticus

The effects of 96 h sub-lethal concentrations of African locust bean effluent on Oreochromis niloticus were studied using plastic buckets. Packed cell volume (PCY) and histological study of gills and liver were the tissue chemistry parameters investigated. The control buckets contained no effluent. Results revealed increase in ESR (Erythrocyte Sedimentation Rate) decrease in haemoglobin, red blood cell and PCY Yalue of the fish exposed to all sub-lethal concentrations. Damage to liver and gills were noticed in some of the sub-lethal concentrations of all the effluent. Normal situation was observed in all the examined tissues of fish from the control buckets. The African locust bean effluent is toxic on O. niloticus and the lethal concentrations of African locust bean effluent deducted from the 96 hours acute toxicity effect ranged from 3ml

Toxicity of Gramoxone super(R) and detergent to nile tilapia (Oreochromis niloticus) L. fingerlings

Acute toxicity tests on the effects of Gramoxone and detergent (both applied as a single dose) to nile tilapia, Oreochromis niloticus, fingerlings (mean weight 2.7~c1 g) were conducted using static bioassay. The 96-h LC sub(50) of Gramoxone and detergent applied were 0.08ml/l and 0.004 g/l, respectively. The fingerlings showed increased hyperactivities exemplified by erratic movement, loss of reflex, and hyperventilation during the period of exposure. These effects increased with increasing concentrations of Gramoxone or detergent throughout the duration of exposure. Tilapia fingerlings of the same size showed different levels of tolerance to the same concentration of both pollutant

Food composition and digestive enzymes in the gut of the African electric catfish Malapterurus electricus (Gmelin 1789) (Malapteruridae)

Analyses of stomach contents of 330 Malapterurus electricus (standard length, 10.1-30.5 cm) in Mahin Lagoon (southwestern Nigeria) established it as a bottom feeder. There was a preponderance of insects accounting for >80% occurrence and >25% of total volume in stomachs of specimens, suggesting a stenophagous predatory habit. Qualitative and quantitative assays of digestive enzymes in the different regions of the gut (oesophagus, stomach, duodenum, ileum, rectum) were investigated. Carbohydrases (amylase, maltase), chitinase, proteases (pepsin, chymotrypsin, trypsin) and lipases were detected in different gut regions with different activity. The pattern of distribution and relative activity of the enzymes correlated with the predatory die