Quantitative distribution and interaction of Salmonella Zega with host cells in visceral organs of chickens infected orally, intraperitoneally and per cloaca.

Immunohistochemical study of the visceral organs of chickens experimentally infected with Salmonella Zega by three routes was carried out to compare the quantitative distribution and interaction of the organism with host cells. 100 birds comprising of 2 week-old chickens were divided into 4 groups of 25 each. Group A was inoculated orally, group B intraperitoneally, group C were administered per cloaca and D were not inoculated and served as control. All the infected birds were inoculated with 0.2 ml of 1 × 108 cfu of the bacteria. Two birds from each group were sacrificed every 24 h post infection. Samples of visceral organs were collected for immunohistochemistry. The distribution of Salmonella Zega in every organ was taken as Mean ± SD of the number of foci of immunoreactions and Compared using a 2-way ANOVA. The interaction of Salmonella Zega with host cells was determined by taking the percentage of the days post infection in which immunoreactions were detected in host cells in each route of infection. The distribution of the organism was highest in the lung of intraperitoneally infected chickens (83.95 ± 27.89) and lowest in the heart (5.21 ± 3.65) of chickens that were infected per cloaca. The highest percentage of interaction of Salmonella Zega was recorded in the epithelial (100%) and blood (100%) cells in all the routes of infection. There were variations in the distribution of Salmonella Zega in visceral organs of chickens but the level of interactions with host cells were similar even when infected through different routes.

Genotoxic, Histopathological and Oxidative Stress Responses in Catfish, Clarias gariepinus, Exposed to Two Antifouling Paints.

BACKGROUND: Antifouling paints are enriched with biocides and employed in the maritime industry to protect moving and fixed surfaces from fouling activities of sea dwelling invertebrates. There is limited information on their effect on the non-target African catfish, Clarias gariepinus, a commonly consumed fish in Lagos. OBJECTIVES: This study investigated the effects of two commonly used antifouling paints (Berger TBT-free (A/F783 (H)), reddish brown color and Silka Marine lead based paint, pale orange color) on a non-target catfish species, Clarias gariepinus. METHODS: The study involved an initial 96-hour acute toxicity assay followed by chronic toxicity evaluation (using 1/10th and 1/100th 96-hour median lethal concentration (LC50) values) for 28 days to determine the ability of the paints to induce micronucleus and red blood cell abnormalities, and histopathological as well as oxidative stress effects in the catfish.Examined anti-oxidative stress enzyme activities include superoxide dismutase (SOD), catalase (CAT), reduced glutathione (GSH) and glutathione-s-transferase (GST). RESULTS: Acute toxicity evaluation results indicated that the Berger paint was 16.1-times more toxic than Silka paint with 96-hour LC50 values of 0.71 mg/L and 11.49 mg/L, respectively. Results from the biochemical assay indicated significantly higher (P<0.05) levels of a lipid peroxidation product, malondialdehyde, in Silka-exposed catfish compared to the control. All enzymes showed significantly higher activities in Berger paint-exposed catfish compared to the control. There was evidence of micronucleated and binucleated cells in the red blood cells of fish exposed to both paints. Histopathological assessment indicated that the exposed fish gills showed evidence of abnormalities such as curved lamellae epithelial necrosis, epithelial lifting and hyperplasia. The liver samples of the catfish showed evidence of portal inflammation as well as mild to severe steatosis, while the gonads showed varying percentages of follicle degeneration. CONCLUSIONS: The present study combined an array of biomarkers to determine the negative health impacts of two commonly used antifouling paints on non-target catfish inhabiting Lagos Lagoon. Further in situ studies are recommended to determine the current status of the lagoon fish. ETHICS APPROVAL: Ethical approval was obtained from the Department of Zoology, University of Lagos, Post-Graduate Committee. Note that this work commenced before the establishment of the University of Lagos Ethical Committee for the use of animals and humans in scientific studies. The committee does not give retroactive approval but stands by existing approvals before its establishment. However, this study followed the World Medical Association principles on the treatment of animals used in research (https://www.wma.net/policies-post/wma-statement-on-animal-use-in-biomedical-research/), and also American Fisheries Society Guidelines for the Use of Fishes in Research (https://fisheries.org/policy-media/science-guidelines/guidelines-for-the-use-of-fishes-in-research/).