Apple Pomace as a Novel Aid for Western Diet-Induced Nonalcoholic Fatty Liver Disease in Young Female Sprague Dawley Rats

Abstract

Apple pomace is a "waste" byproduct of apple processing that causes environmental pollution and is costly to dispose of. Yet, apple pomace is rich in dietary fibers and antioxidants. Analysis of apple pomace's nutritional profile indicates suitability as a potential dietary treatment for nonalcoholic fatty liver disease (NAFLD) and the more severe non-alcoholic steatohepatitis (NASH). NAFLD is the most prevalent liver disease in the world with prevalence and severity expected to increase in both adults and children. Currently, there is no approved drug treatment for NAFLD and therefore, dietary intervention is the primary treatment. The study objectives were to determine the effect of apple pomace consumption on diet-induced NAFLD, NASH and renal and bone health using a rodent model. Growing (aged 22-29 d) female Sprague-Dawley rats (n=8/group) were fed ad libitum diets consisting of AIN-93G, AIN-93G with 10% apple pomace substitution (AIN/AP), Western diet (45% fat, 34% sucrose), or Western diet with 10% apple pomace substitution (Western/AP) for 8 weeks. Results showed Western diet consumption increased (p<0.0001) gonadal adipose weight independent of body weight differences. Rats consuming Western diet showed histological evidence of hepatic fat infiltration and inflammation characterizing NAFLD and progression to NASH. Fatty acid analysis by gas chromatography showed increase (p<0.05) hepatic palmitic, palmitoleic, and oleic acid content in rats consuming Western diet was attenuated by apple pomace. Gonadal adipose tissue fatty acid analysis showed rats consuming a Western diet to have significantly reduced palmitic, stearic, and oleic acid compared to all diet groups. These results suggest saturated and monounsaturated fatty acids from the adipose tissue are being transported to the liver, resulting in increased hepatic fat deposition. Additionally, hepatic gene expression by real time-quantitative polymerase chain I would like to thank my parents for continually supporting and encouraging me over the course of my schooling. Without your guidance and patience, I would surely not be the person, student, or scholar I am today. Thank you for all that you have done to prepare and support me over the course of my doctoral studies, before, and all you will do after. I love you both. I would also like to thank my girlfriend, Rebekah Honce, soon to be PhD. You have been the best girlfriend, support system, stress reliever, editor, therapist, and friend since we began dating. You have helped me grow as a person and as a scientist and I will forever be grateful you are a part of my life. I love my Bek. Thank you to Janet Tou for accepting me into your lab, keeping me focused, allowing me to pursue my interests, and helping me to shape my future. I am very lucky to have enrolled in your course during the course of my Master's, and even more to have been your student the past three years. Thank you to my committee for the aid in methods and analysis, being available for questions and conversations, and for conversations...