Impact of a High-Protein Diet Associated with Probiotics on Lipid Profile, Oxidative Stress, and Mitochondrial Activity in Adipose and Muscle Tissues of Wistar Rats.

BACKGROUND/OBJECTIVES: High-protein (HP) diets may influence body composition, lipid metabolism, oxidative stress, and mitochondrial function, but their interaction with probiotics remains unclear. This study evaluated the effects of HP feeding, alone or combined with Lactobacillus acidophilus and Bifidobacterium lactis, on metabolic, redox, mitochondrial, and plasma amino acid parameters in Wistar rats. METHODS: Thirty-two male Wistar rats were allocated to standard diet (SD), SD plus probiotics, HP diet, or HP plus probiotics for 10 weeks. Body weight gain, food and energy intake, visceral adiposity, plasma biochemical profile, adipose tissue histology, oxidative stress markers, mitochondrial electron transport chain activity, and plasma amino acids were assessed. RESULTS: Food and energy intake did not differ among groups. HP-fed animals showed lower weight gain, reduced visceral fat, and lower total cholesterol and triglycerides. Probiotics modulated selected redox-related outcomes, including methylglyoxal and sulfhydryl levels, with tissue-specific responses. Complex I activity increased in adipose tissue and skeletal muscle, and plasma amino acid profiles were altered, particularly glutamate, leucine, aspartate, alanine, and methionine. CONCLUSIONS: HP feeding, with or without probiotics, modulated metabolic, redox, mitochondrial, and amino acid-related parameters in Wistar rats. These findings suggest that HP diets and probiotics may influence cardiometabolic adaptations, although tissue-specific responses and mechanisms require further investigation.