Nile Rat as a model for Type-II Diabetes Mellitus Development in Humans: assessing the impact of hiFiber from commercial chows [Rabbit and Chinchilla chow] vs hiCHO semipurified diets with or without carrot fiber
Creators: name: Jang, In Won
Publisher: name: Brandeis University
Year: 2021
Subjects: Arvicanthis niloticus
Fiber
Nile Rat
nutrition
T2DM
Diabetes

description: Type-II Diabetes Mellitus has been a growing concern for the world for the past several decades and continues to be on the rise. Despite research efforts, there have been questions on
description: how impactful genetics can be in determining susceptibility to the metabolic syndrome, and how the macronutrient makeup of a diet, particularly in the displacement of carbohydrates, will affect T2DM development as well. A paper published by a molecular genetics lab from the University of California in Santa Barbara convincingly showed that rabbit chow, a high fiber diet, could protect Nile rat pups from diabetes throughout their lives even if the diet was fed only to the mothers during pregnancy. This paper raised the question; what exactly does rabbit chow do to the Nile rat to prevent this diabetes? Nile rat breeders were fed either commercial rabbit chow or mouse chow in order to produce pups that continued to be fed either of those chows so a comparison could be made on growth rate and the development of diabetes as measured by RBG, caloric intake, and organ weights at necropsy. After six weeks on either diet the pups were weighed and RBGs collected in order to assign the pups as either resistant or susceptible to diabetes. After 3 more weeks on their original diet, with additional assessment of diabetes, pups were then crossed over from rabbit chow or mouse chow to semi-purified diets containing high carb [hiCHO] as Diet 133 [0% fiber] or 133 + fiber [Diet 230, 4.5% fiber]. At this point the pups were continued for another 4 weeks to determine whether the initial rabbit chow upbringing exerted any protection against diabetes development during the 4-week second trial to 13wks of age. The results revealed that rabbit chow reduced the growth rate of pups (about 40%) in concert with their much lower RBG (40-50%). Furthermore, the rabbit chow history proved to be protective against the addition of high carb (CHO) semi-purified Diet 133 exposure, whereas pups raised on mouse chow continued to have higher RBG and diabetes whether or not they were transferred onto Diet 133 or Diet 230. In addition, at necropsy, we found that rabbit chow-fed Nile rats presented a normal liver and an enlarged cecum, indicating that the microbiome of these rats was affected. These rabbit chow rats also presented with much lower amounts of adipose tissue. Surprisingly, caloric intake measured in young adults fed the 5 different diets, found all the chow diets about equal and 15% less than the semipurified diets. [p&lt;0.05]. These data indicate that rabbit chow [22% fiber] was associated with reduced growth and less diabetes than similar pups raised on mouse chow [3% fiber] or Diet 133. [0% fiber]. After the dietary crossover at 9 weeks of age, Diet 230 [4.5% fiber], a hiCHO diet with fiber, was intermediate in nature, relative to RBG and diabetes, whereas rabbit chow protected against any increase in RBG and diabetes. Therefore, the inclusion of dietary fiber, in this case, in the form of rabbit chow early in development, was extremely important for the Nile rats’ metabolic health, including protection against T2DM. Although both the semipurified diets resulted in greater caloric intake than the chow diets in the young adults tested, the mouse chow diet with high diabetes did not result in high calorie intake. Furthermore, despite the diets with the highest fiber content [18-22%] decreasing caloric intake to support slower growth, it was not a consistent story for the mouse chow. More research is needed for caloric intake in young growing rats to pursue these points.