Phytochemical profiling and anthelmintic potential of extracts of selected tropical plants on parasites of fishes in Epe Lagoon

This research aims to study the anthelmintic properties of selected five (5) tropical plant extracts, ascertained margin of fish host safety in reference with praziquantel, a commonly used chemo-therapeutics. Qualitative and quantitative analysis of Alligator pepper seeds (Aframomum melegueta), Moringa leaves (Moringa oleifera), Neem leaves (Azadirachta indica), Ginger bulbs (Zingiber officinale) and Garlic (Allium sativum) and their potencies in reference to praziquantel against Clarias gariepinus and different classes of helminth parasites were investigated. The results obtained show that the 70% ethanol extract had 80 to 100% presence of the phytochemical content, compared with the 100% aqueous and 100% ethanol extracts with 50 to 80% and 50 to 90%, respectively. Among the five tropical plants, the richest in saponin and flavonoids are alligator pepper and neem with alkaloids, tannin, flavonoid and saponin in ratios 1:1:3:9 and 1:1:4:3 respectively. While, moringa, garlic and ginger are rich in alkaloids with alkaloids, tannin, flavonoid and saponin in ratios, 8:1:10:1, 6:2:1:4 and 6:3:2:1, respectively. Aframomum melegueta and praziquantel showed above 70% potency (at 96 h LC5) against all the classes of parasites; Wenyonia spp (cestode), Procamallanus spp (nematode), Tenuisentis spp (acanthocephalan), and Electrotaenia sp (cestode) as compared to the other plant extracts that showed above 70% potency (at 96 h LC5) only against Electrotaenia spp. Sub-lethal Concentrations (96 h LC5) of praziquantel and Aframomum melegueta on the juvenile fish host (12.36 mg/l and 9.9 mg/l respectively) were found to be 90.9% and 93.5% effective against adult Electrotaenia spp after 8 to 10 min of exposure. These concentrations were 78 to 85.7% and 89.7 to 88.4%, respectively, effective against the other classes of parasites after 18 to 25 min and 15 to 21 min of exposure. These concentrations were tested on the post juvenile of the fish to determine behavioral changes; there were no significant behavioral responses after 24 h of exposure. The effective concentrations indicate the widest margin of safety for the fish host.

Bioaccumulation of Organochlorine Pesticides, Procamallanus sp. (Baylis, 1923) infections, and Microbial Colonization in African Snakehead fish Sampled from Lekki Lagoon, Lagos, Nigeria

The exponential rise in the Nigerian population has necessitated the use of agrochemicals for enhanced agricultural yields to meet the ever-rising demand for food. However, agrochemicals such as organochlorine pesticides (OCPs) have caused several devastating health and ecological challenges. The study was therefore aimed at assessing the bioaccumulation of OCPs and the associated parasitological and microbial susceptibility in P. obscura to determine the possible ecological impacts of the chemical. A total of 106 specimens of Parachanna obscura fish species were sampled between July and November 2019 from Lekki Lagoon in Lagos, Nigeria. Four culture media, namely nutrient agar (NA), MacConkay agar (MCA), eosin methylene blue (EMB), and sabouraud dextrose agar (SDA) were employed in microbial culture. These microbes were subjected to ceftazidime, ceftriaxone, cefuroxime, gentamicin, ofloxacin, augmentin, nitrofurantoin, ciprofloxacin, and erythromycin to test for resistance, susceptibility and intermediate statuses before and after curing. OCPs were tested in the water, sediment, and tissues of P. obscura using gas chromatography flame ionization detector (GC-FID). P. obscura sampled in the lagoon had poor growth exponent which was characterized by negative allometry (slenderness) in the sampled fish. Although the incidence of parasitic infection in the fish was not alarming, the situation might be aggravated if the prevalent anthropogenic activities persist, resulting in immunosuppression. Regulation of anthropogenic activities in the catchment area is recommended to forestall the prognosis of health and environmental hazards associated with the agricultural, industrial, pharmaceutical, and municipal activities around the lagoon. Bacteria that conferred the most resistance to the majority of the antibiotics were Staphylococcus sp., Micrococcus sp. Escherichia coli and Klebsiella sp., testing positive to plasmid profile. They conferred high resistance to the antibiotics before plasmid curing but became highly susceptible post- plasmid curing. This implies that the gene for resistance in the bacteria isolates was plasmid-mediated, that is, they were obtained from the environment. In the event of an outbreak of waterborne diseases such as cholera, typhoid, dysentery, and diarrhea, there may be non-response to treatment among the infected inhabitants. The incidence of antibiotic resistance in bacteria colonies recorded in this study is of great public health concern, given the possibility of the antibiotic-resistant bacteria strains being passed to humans through fish consumption, resulting in increased multi-drug resistance in humans. Regulation of anthropogenic activities around the lagoon is recommended to forestall prognosis of health and environmental hazards associated with OCPs from agricultural, industrial, pharmaceutical, and municipal sources.

Comparative Bioaccumulation of PAH and BTEX in Malapterurus electricus (Siluriformes: Malapteruridae) and its Enteric Parasite, Electrotaenia malopteruri Sampled from Lekki Lagoon, Lagos, Nigeria

Contamination of Lekki lagoon by petrogenic chemicals such as polycyclic aromatic hydrocarbons (PAH) and benzene, toluene, ethylbenzene, and xylene (BTEX) has been widely reported. The study was aimed at investigating the bioaccumulation of PAH and BTEX in Malapterurus electricus collected from Lekki lagoon in Lagos, Nigeria. BTEX was analyzed in the intestine, water, and sediment samples using 8260B Agilent 7890B gas chromatograph coupled to a mass spectrometer (GC-MS). While PAHs were tested in the same media using a gas chromatograph coupled to a flame ionization detector (GC-FID). Histopathological analysis of the fish intestine was conducted using haematoxylin and eosin (H&E) stains. Parasite intensity, antioxidant enzymes, and lipid peroxidation activities were investigated in the fish. The parasitic infection detected in Malapterurus electricus was Electrotaenia malopteruri. The parasite showed weak and no depurative capacities for BTEX and PAH respectively. The decrease in superoxide dismutase (SOD), catalase (CAT), and reduced glutathione (GSH) in conjunction with an increase in Malondialdehyde (MDA) characterized relatively higher susceptibility among the male fish. Varieties of tissue injuries increased with the standard length of the fish groups. Results suggest that lengthier and uninfected M. electricus were more susceptible to PAH in Lekki lagoon than the shorter and infected ones. The study demonstrated a promising tendency of the enteric parasite, E. malopteruri to depurate chlorobenzene, ethylbenzene, o-xylene, m+p-xylene, and 1,4-dichlorobenzene from the intestine of its host fish, M. electricus, while PAHs were poorly mediated by the parasite.

Bioaccumulation of Pyrethroid in Parasite Wenyonia acuminata (Cestoda: Caryophyllaeidae) and Host fish Synodontis clarias (Linnaeus, 1758) from Lekki Lagoon, Lagos Nigeria

This study was aimed at determining the concentration of pyrethroid in the surface water, sediment, Weyonia acuminata and Synodontis clarias fish in Lekki lagoon, Lagos, Nigeria. In-situ physicochemical analysis of the surface water was conducted using a calibrated handheld multi-parameter probe (Horiba Checker Model U-10). Intestinal samples from infected and uninfected fish were analyzed for pyrethroid concentrations, microbial colonization, proteins (PRO), superoxide dismutase (SOD), catalase (CAT), reduced glutathione (GSH), malonaldehyde (MDA) and glutathione peroxidase (GPx). The histopathology of infected and uninfected intestinal tissues were analyzed using Haematoxylin and Eosin (H&E) stains and examined under a binocular light microscope (Model 230485). A total of 39 out of 98 S. clarias fish were infected with cestode parasite, Wenyonia acuminate, amounting to 39% parasite prevalence. Among the tested pyrethroids, Cyfluthrin and Alpha -cypermethrin had significant sorption of 1.62 and 3.27 respectively from the aqueous phase to the bottom sediment of the lagoon. Pyrethroid concentration was in the order of sediment > parasite> water > intestine> liver. The cholesterol, triglycerides, and LDL (low density lipids) in the parasite were higher than in the host fish (p<0.05). On the other hand, the fish hepatic protein, high density lipids (HDL) and glucose were higher than the levels in the parasites (p<0.05). There was a high prevalence of gut microbes (30 - 40%), which include Salmonella sp, Escherichia coli, Pseudomonas sp and Bacillus sp among individuals infected with gut Cestodes, Wenyonia sp compared with uninfected individual which had higher gut Staphylococcus sp., Klebsiella sp., and Proteus sp. (10- 40%). among the congeners of pyrethroids analyzed, Cyfluthrin > Alpha-Cyermethrin had significant sorption on the sediment, however unlike a benthopelagic fish, no pyrethroid was accumulated in the S. clarias from the sediment. The fish however accumulated Alpha-Cypermethrin from the aqueous phase. The parasite on the other hand accumulated Bathroid significantly from the surface water and bottom sediment which may be linked to the higher stress levels observed in the parasite than the host fish. The parasite in turn inflicted histological alterations on the host intestine, marked by moderate inflammation of mucosa, alteration of the villi microstructure, moderate stunting of the villous structure and moderate fibrosis of villous structure. The study demonstrated the efficiency of histopathological and microbial analysis in biomonitoring studies enteric parasites and early detection of pyrethroid toxicity respectively compared to bioaccumulation analysis.

Heavy metals, parasitologic and oxidative stress biomarker investigations in Heterotis niloticus from Lekki Lagoon, Lagos, Nigeria

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Occurrence of parasites in fish could bio accumulate heavy metals by as much as 200 % more than values present in fish tissues.

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Parasitic infection in fish is positively skewed towards male fish.

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Parasitism in fish alters histological structures of vital fish organs.

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Combined effects of parasitism and heavy metal pollution in fish elicits antioxidant response in fish.

Heavy metal toxicity in aquatic life as a result of human activities poses a grave health threat to water quality, aquatic and human life. Parasites may serve as indicators of heavy metal pollution. This research investigated the health status of the fish Heterotis niloticus viz-a-viz quality of the water and sediments in Lekki lagoon, parasitic infection, presence of heavy metals and oxidative stress response in the liver and intestine of the fish. Parasites recovered were also analyzed for the extent of bioaccumulation of heavy metals. The metals in water, sediments, parasites, and fish were analyzed using Atomic Absorption Spectrometry. Heavy metal concentrations in the surface water were generally below regulatory limits of World Health Organization. Sediment had high levels of aluminium (124.78 mg/kg) and iron (327.41 mg/kg); other heavy metals were below regulatory limits. Tenuisentis niloticus, an acanthocephalan, was the only parasite recovered. Seventy (70) out of 100 fish sampled were infected with the parasite. T. niloticus bioaccumulated Cd, Ni, and Pb between 65 to 100 times more than the liver and 12 to 200 times more than the intestine. Other metals bioaccumulated from the host tissues by the parasite had the magnitude between 1 to 12 times as the liver and 1 to 30 times as the intestine. There were significant differences in the activities of antioxidant enzymes between the parasitized and non-parasitized fishes. Fish tissues also showed histological alterations, ranging from mild infiltration of inflammatory cells to moderate inflammation and haemorrhagic lesions. Human activities that introduce stressors into the lagoon should be controlled.

Bioaccumulation of BTEX and PAHs in Heterotis niloticus (Actinopterygii) from the Epe Lagoon, Lagos, Nigeria

Toxicity studies in the aquatic ecosystem have shown that petrol and its product have adverse effects on aquatic biota. They are able to easily absorb these toxic substances into their bodies from sediment, water or even food items that are contaminated, thus impacting the food chain. In this study, water, sediment and fish (Heterotis niloticus) from the Epe Lagoon were investigated for the presence of BTEX (benzene, toluene, ethylbenzene and the three xylene isomers m, o and p-xylenes), and PAHs using GC-MS. Total concentration of BTEX in sediment and water was respectively 32.37 ± 1.07 μg/g, 49.86 ± 7.30 μg/L; while total concentration of BTEX in fish liver and intestine was 33.75 ± 10.09 and 40.16 ± 9.64 μg/g respectively. Benzene, 1,2-Dichlorobenzene and 1,3-Dichlorobenzene components of BTEX were not detected in both sediment and water. Total concentration of PAH in sediment and water was 7.46 ± 1.73 μg/g and 19.33 ± 1.31 μg/L respectively. Total PAHs concentration in liver and fish intestine was 141.23 ± 5.89 and 173.34 ± 4.677 μg/g respectively. Majority of the PAHs congeners were found to be higher than the acceptable limits. Findings from this study shows the need for continuous monitoring of our natural waters as the present situation portends a potential concern for ecological risk.

Biomonitoring, physico-chemical, and biomarker evaluations of abattoir effluent discharges into the Ogun River from Kara Market, Ogun State, Nigeria, using Clarias gariepinus

The discharge of untreated effluents into aquatic ecosystems poses potential adverse effects to aquatic organisms. In this study, the physico-chemical characteristics of abattoir effluent from Kara Cow Market, Ogun State, Nigeria, surface water and sediments from the Ogun River were evaluated. Fish species and macrobenthic fauna diversity in the river were also examined. Acute toxicity and biochemical and histological studies were investigated in Clarias gariepinus exposed to sub-lethal concentrations of the effluent over a period of 28 days. Effluent physico-chemical parameters such as ammonia, conductivity, total dissolved solids, and total suspended solids were higher than set limits. Total polycyclic aromatic hydrocarbons (PAHs) in the effluent and sediment were 6.73 mg/L and 8.07 mg/kg, respectively. Tetracycline (an antibiotic administered to the cows at the market) levels in the effluent and surface water were 0.23 μg/mL and 0.85 μg/mL, respectively. Fish species diversity was lower at the test site compared to the reference site. Chironomus spp. and Tubifex tubifex dominated the benthic assemblage at the test site. There were significant changes (p < 0.05) in the biochemical indices but no histological alterations in exposed C. gariepinus after 28 days. The results demonstrate that the effluent poses potential risks to the aquatic organisms and ecosystem services provided by the river. We recommend that environmental regulatory agencies and stakeholders should establish effluent and solid wastes management systems at the market to prevent environmental and public health epidemics within the framework of the United Nations Sustainable Development Goals 6 (clean water and sanitation) and 14 (life below water). Graphical abstract ᅟ.

Acute toxicity of premium motor spirit to the guppy (Poecilia reticulata, Peters, 1859)

Static bioassays were made to determine acute toxicity of premium motor spirit on poecilia reticulata. Lethal doses of the oil were determined using LC50 software programmes based on Finneys probit statistical method. The 96 LC50 value of the oil for guppy was estimated as 1.69 (1.13-2.43) mg L(-1). The fish exhibited behavioural changes in the form of aggression, rapid gulping of water, increased opercular movement and abnormal swimming movements. The significance of this sublethal effect particularly as a stress indicator of petrol oil contamination was discussed.

Size, sex and seasonal dynamics in the dietary composition of Brycinus nurse (Pisces: Characidae), from Asa reservoir, Ilorin, Nigeria

Specimens of the characid Brycinus nurse (N = 980) were collected in Asa reservoir, Nigeria, from November 1991 to October 1993. The diet was analyzed from stomach contents using the frequency of occurrence, numerical and gravimetric methods. Fish sex affected occurrence, number and weight of food items. The relative importance index (RI) indicates that diet varied seasonally. There was also a noticeable switch from insectivorous habits in small fish (less than 18 cm) to herbivorous feeding habits in larger fish. The ability of the fish to evolve trophic strategies that ensure optimum foraging despite seasonal changes can account for its success in the lake.

The diet of Brycinus nurse (Pisces: Characidae) from Asa reservoir, Ilorin, Nigeria

From November 1991 to October 1993, 980 specimens of the characid Brycinus nurse were collected from Asa reservoir to examine its diet. The diet was analyzed using the frequency of occurrence, numerical and gravimetric methods. Two hundred and sixty nine (27.45%) of the stomachs examined were empty. The fish was an omnivore feeding extensively on a wide array of plant and animal food items. These consisted of 9 families, 10 genera and 10 species. The most extensively consumed plant food item was aquatic plant parts which occurred in 63.88% of the stomachs, and accounted for 6.06% by number and 12.10% by weight while the ephemeropteran, Povilla adusta was the most dominant animal food item, occurring in 50.92% of the stomachs, and accounting for 11.98% by number and 11.86% by weight. Conversely, the least consumed plant food item was Volvox occurring in 4.49% of the stomachs and accounting for 0.18% by number and 0.35% by weight, while the fish Barbus sp. was the least consumed animal food item occurring in 0.51% of the stomachs, accounting for 0.03% by number and 1.62% by weight. New food items not previously recorded such as a watermite. Aspatharia sinuata and Barbus callipterus were found in the stomach contents. The nonspecific feeding regime of the fish and its ability to utilize different food items effectively was what accounted for the prominence and wide distribution of the fish in the lake.