Effect of cultured white soft cheese on the histopathological changes in the kidneys and liver of albino rats

Abstract

Three different types of lactic acid bacteria (Lactobacillus helveticus, Lactobacillus rhamnosus and Streptococcus thermophilus S₃₈₅₅) were used to manufacture white soft cheese. The resultant white soft cheeses were pickled for 28 days at refrigerator temperatures and were fed to the experimental rats. The chemical and microbiological analyses of white soft cheese were conducted at different storage periods (fresh, 7 days, 14 days, 21 days, and 28 days). The pH values and protein content of white soft cheese gradually decreased during the storage peroid. Conversely, the moisture content, titratable acidity, and fat/DM % of white soft cheese were found to increase with of the increase in pickling periods of up to 28 days. Microbiologically, the total viable count of bacteria in the control samples was lower than that in the other treatments. Furthermore, the treatments containing the L. helveticus and L. rhamnosus strains had the highest lactoacilli counts whereas the treatment containing the S. thermophilus strain had the highest streptococci counts. Twenty-five male Albino rats were used for experiemntal technique. Rats were fed with 70% basal diet with addition of 30% white soft cheese. Several pathological findings were present in all experimental groups apart from the control rats, and the kidney samples exhibited renal vascular congestion especially in the cortical area. The changes of the glomeruli comprise atrophy, distortion, hypocellularity of the glomerular tuft, and focal lymphoid cell reactions. The renal tubular epithelium showed a series of degenerative changes ranging up to necrosis. The liver samples showed variable hepatic injury in the form of thickening in the Glisson capsule, as well as dissociation and disorganization of hepatic cords. Hepatocellular vacuolar degeneration, presence of focal areas of nodular hyperplasia, the hyperplastic cells mixed with lymphocytic infiltration, congestion in the portal vein, periportal fibrosis and edema with the presence of newly formed nonfunctional bile ductulus. Based on the histopathology scores, the severity of renal and hepatic changes was significantly increased (P ≤ 0.05) in all of the experimental groups compared with the control group. Generally, the chemical composition, microbiological analysis and vital organs were significantly affected by using cultured white soft cheese.