Background: Formalin is a highly toxic chemical that causes tissue damage. Formalin is metabolized by the liver and erythrocytes and excreted via the urinary and digestive tracts. This passage may propose toxicity in these systems. Thus, the current study was conducted to examine serological, and histological changes in the kidney and liver of formalin-vapor-exposed quails (FVEQs) (Coturnix coturnix) to promote awareness of formalin toxicity in the farms of Japanese quails. Methods: The study included the recruitment of 16 adult quails divided into four equal groups; control group (no formalin exposure), FVEQ1 group (exposed to formalin for 10 days), FVEQ2 (exposed to formalin for 20 days), and FVEQ3 (exposed to formalin for 30 days). All FVEQs were exposed to formalin vapor twice daily (morning and evening, 2hrs/each). Each group was reared in a separate airtight chamber during the experiment time (10, 20, or 30 days). blood samples for renal and liver, IgG levels, and histopathological features were examined. Results: The findings showed significant (p<0.05) increases in the levels of blood creatinine, urea, and uric acid in the FVEQ groups. Liver enzymes, ALP, ALT, and AST revealed significant (p<0.05) increases in the FVEQ groups. FVEQ1 group recorded significantly (p<0.05) the highest IgG level after 10 days of formalin exposure, which significantly (p<0.05) decreased after 10 days without formalin exposure, and immunity was slightly restored. The histopathological characteristics of the kidney were increases in the thickness of renal corpuscles, glomeruli, and the Henle loop of the medullary cone. For the liver, the findings showed increases in the parenchymal aggregation of lymphoid cells. There were amyloid depositions in hepatocyte spaces, which were squeezed and atrophied, creating intercellular gaps and reducing cell compactness. Conclusion: The inhalation of formalin vapor may damage the kidney and liver tissues and eventually their functioning in formalin-exposed quails.

The adrenal glands are endocrine glands that produce a diversity of hormones comprising of adrenaline, the aldosterone and cortisol. The present study aimed at investigation of the histomorphometric features of chromaffin cells. There were two types of chromaffin cells. In squirrel, the first type was columnar in shape and brownish in color contained spherical nucleus located at the base of cells, which represented the epinephrine secreting cells, and the second type was polygonal in shape and light brownish in color contained spherical nucleus located in the center of cells, which represented the norepinephrine secreting cells. The adrenal medulla of hamster consists almost entirely of columnar or polyhedral chromaffin cells forming clusters and anastomosing cords separated by sinusoids, giving a strong reaction with methylene eosin stain more than that seen in squirrel. The statistical analysis showed that the means diameter of epinephrine cells and norepinephrine cells in the right adrenal gland in squirrel were lesser than those of hamster significantly at P<0.05, but in the left adrenal gland in squirrel the means were greater than those of hamster significantly at P<0.05. In conclusion, the present findings showed the reaction of chromaffin cells of hamster with methylene –eosin stain to be stronger than with hematoxylin-eosin stain, while the opposite was true in case of the squirrel

Given the physiological significance and the need for further physiological and morphological knowledge of the adrenal glands, the objectives of the current study were to compare morphometric data between the right and left adrenals of male squirrels and hamsters. The study was conducted on five squirrel males and five hamster males. The glands in both animals were removed and fixed in neutral formalin solution. It was found that the squirrel contains two brown-colored right and left adrenal glands connected anteriorly and medially to each cranial pole of the kidney, and the right adrenal gland had a longitudinal shape, while the left gland had an oval shape. Hamsters had two pairs of brown adrenal glands located anteriorly attached to each kidney's cranial pole. The right adrenal gland was round in shape, while the left was oval. The statistical results showed a significant difference between the left and right suitable adrenal glands in both animals, as well as a significant difference between the squirrel gland and the hamster gland, where it was found that the right and left squirrel glands are larger more significant, heavier, longer and thicker than the adrenal gland in hamsters after the following measures were adopted: weight, length, thickness, width, and size.