Effects of supplementary protein source, autoclaving diets, and gender on biochemical blood parameters, oxidative stress markers, and caecal fermentation in rats.

Abstract

BACKGROUND: The study aimed to assess the effects of supplementary protein source, thermal processing of diets, and gender on the health status of rats over a six-month-long feeding trial. The experiment was performed on 216 adult Crl:W (Han) Wistar rats, 108 males and 108 females, divided into nine groups fed a commercial SSNIFF (SN) diet or cereal-based diets containing soybean meal (SBM), or sodium caseinate (NaC) as a supplementary protein sources. The diets were non-autoclaved (T0), autoclaved at 121 °C for 20 min (T1), or autoclaved at 134 °C for 10 min (T2). RESULTS: Males displayed higher levels of amylase, phosphorus, glucose, and uric acid and lower levels of albumin, bilirubin, and iron in the blood than females. Males also experienced greater oxidative stress. In contrast, female rats had higher concentrations of short-chain fatty acids (SCFA) in the caecal digesta. Rats fed SBM and NaC diets had similar blood biochemical parameters, though NaC groups had higher cholesterol, triglycerides, and alanine aminotransferase levels. Oxidative stress markers were lower in rats fed SBM and NaC diets, which also aligned with increased SCFA concentrations in ceacal digesta in those animals. Autoclaved diets reduced feed intake and body weight gain and increased isoacids concentrations. CONCLUSION: The SBM diet appeared more beneficial than NaC diet due to an improvement in prooxidants-antioxidants balance and caecal fermentation. Feeding autoclaved diets reduced feed intake and body weight gain but had no negative impact on blood parameters and weights of internal organs. Autoclaving according to the T1 program can be recommended for laboratory animal breeding. Numerous interactions indicate a need for further studies to elucidate the mechanisms underlying different response of males and females to a diet. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12917-025-05266-x.