Investigating the Effects of Modifications to Dietary Protein Sources Using Ammonium Hydroxide Enhancement in a Mouse Model for Diet-Induced Obesity

The mechanisms by which dietary protein sources, and red meat in particular, help maintain metabolic health, especially during aging and disease, is undervalued. Furthermore, little is known about the sex-based physiological responses to different dietary protein sources. The current diet-induced obesity epidemic is critically taxing human health due to the co-morbidities associated with hyperlipidemia. Dietary interventions that are affordable and promote adherence are critical to identify. The potential health benefits, and long-term health impacts of directed dietary protein modification have yet to be explored. Ammonium Hydroxide Enhancement (AHE) of red meat products is a USDA approved process insuring food safety for consumers. In this study, AHE of dietary protein sources (DPS) in a high-fat diet context was investigated to determine potential metabolic health benefits and impacts to health with again. To that end, C3H/HeJ (C3H/HeJ) were established as a model for chronic dietinduced obesity to provide a nuanced approach to observing obesity as a chronic disease state. The potential of AHE to dietary protein to attenuate the effects of chronic DIO was also explored at the physiological and molecular level. It was found that AHE of a protein DPS can modulate longevity and mass composition in a sex- and DPS-dependent manner. Moreover, it was demonstrated that DPS has a strong influence on modulation to signaling in canonical pathways in the liver transcriptome. This modulation can be further influenced by the addition of AHE, and that sex is a key contributor to metabolic outcomes. Metabolite profiles were primarily modified over time by a high-fat (HF) beef diet with AHE (HFBN) in males. Interestingly, more subtle changes were observed in females as the result of a HF casein diet with AHE (HFCN). Levels of liver proteins were also impacted by AHE and DPS. In females, the main changes were observed in CYP3A4 expression as the result of the HFBN diet. In males, HFBN served to increase GS levels compared with other diets. Our results taken together, demonstrate a beneficial role of AHE in mitigating High-Fat Diet-induced, metabolism-associated liver dysfunction in a sex-dependent manner and in aging.