Antioxidant Activity of Coated Probiotic Lactobacillus casei on Chromium(VI) Induced Oxidative Stress in Rats

Protective effects of non-encapsulated and microencapsulated Lactobacillus delbrueckii subsp. bulgaricus in rainbow trout (Oncorhynchus mykiss) exposed to lead (Pb) via diet

The present study was designed to investigate the effects of dietary non-encapsulated and microencapsulated Lactobacillus delbrueckii subsp. bulgaricus on growth performance, intestinal enzymatic activities, antioxidant capacity and hepato-biochemical parameters of rainbow trout before or after exposure to lead via diet. Fingerling fish (16 ± 4 g) were divided into four groups: negative control (NC), positive control (PC), probiotic (PR) and encapsulated probiotic (EN-PR). During the pre-exposure period (days 0-45), fish in the NC and PC groups received the basal diet, whereas fish in the PR and EN-PR groups were fed with basal diet containing 108 CFU g−1 feed of non-encapsulated and microencapsulated probiotic, respectively. During the exposure period (days 46-66), the fish in the probiotic and PC groups were co-treated with 500 μg g−1 feed of lead nitrate. Blood, liver and gut samples were taken at days 0, 45, 52, 59 and 66. The results revealed that growth performance and intestinal enzymatic activities were significantly (p< 0.05) improved in the probiotic groups compared to the NC group (day 45). Dietary exposure to lead resulted in the highest levels of liver aspartate aminotransferase (AST), liver alkaline phosphatase (ALP) and serum malondialdehyde (MDA), and the lowest activities of serum superoxide dismutase (SOD) and catalase (CAT) in the PC group (day 66). The levels of liver ALP were significantly (p< 0.05) lower in the probiotic groups compared to the NC and PC groups prior to and after exposure to dietary lead. Serum levels of total protein, albumin, SOD, CAT and glutathione (GSH) were significantly increased in fish fed with both non-encapsulated and microencapsulated probiotics (p< 0.05). However, microencapsulated probiotic showed the greatest potential for alleviation of the disturbed activities of intestinal and hepatic enzymes, and improvement of serum biochemical and antioxidant parameters. Our findings suggest that L. delbrueckii subsp. bulgaricus, particularly in the microencapsulated form, can be used as a potential probiotic to protect rainbow trout from dietborne lead toxicity.

Strain-Specific Quantification of Native Probiotic Bacillus spp. and Their Effect on Liver Function and Gut Microflora of Experimental Rats

Safety and efficacy was investigated for two candidate probiotic B. flexus MCC2427 and B. licheniformis MCC2512 via in vivo studies on albino Wistar rats. In acute toxicity assay, rats were fed with single dose of 10¹⁰ cfu mL^-1 of probiotics. The follow-up studies for next 14 days did not reveal any toxicity-related criteria indicating the non-toxicity nature of probiotics. In 90-day repeated dosage studies, the cultures were administered in three doses (10⁶, 10⁷, 10⁸ cfu mL^-1). Results showed no overt toxic effect and no drastic treatment-related changes pertaining to histopathology of vital organs. DNA fingerprinting indicated the lack of bacterial translocation. Superoxide dismutase and catalase activity indicated their antioxidant potential. Reduced serum cholesterol with improved HDL-cholesterol specified the cholesterol-reducing ability of the cultures, which was also apparent with increased excretion of cholic acid in feces. Both probiotic cultures positively altered the gut microbial environment, retained lactic acid bacterial effect, and simultaneously reduced pathogenic strains. A sensitive and rapid tool was developed using strain-specific qPCR primers, which facilitated appropriate estimation of test culture in feces. The data strongly advocate the safety of tested probiotics at levels used in the study.