Type II diabetes mellitus (T2DM) is a multifactorial disease involving complex genetic and environmental interactions. No single animal model has so far mirrored all the characteristics or complications of diabetes in humans. Since this disease represents a chronic nutritional insult based on a diet bearing a high glycemic load, the ideal model should recapitulate the underlying dietary issues. Most rodent models have three shortcomings: (1) they are genetically or chemically modified to produce diabetes; (2) unlike humans, most require high-fat feeding; (3) and they take too long to develop diabetes. By contrast, Nile rats develop diabetes rapidly (8–10 weeks) with high-carbohydrate (hiCHO) diets, similar to humans, and are protected by high fat (with low glycemic load) intake. This review describes diabetes progression in the Nile rat, including various aspects of breeding, feeding, and handling for best experimental outcomes. The diabetes is characterized by a striking genetic permissiveness influencing hyperphagia and hyperinsulinemia; random blood glucose is the best index of disease progression; and kidney failure with chronic morbidity and death are outcomes, all of which mimic uncontrolled T2DM in humans. Non-alcoholic fatty liver disease (NAFLD), also described in diabetic humans, results from hepatic triglyceride and cholesterol accumulation associated with rising blood glucose. Protection is afforded by low glycemic load diets rich in certain fibers or polyphenols. Accordingly, the Nile rat provides a unique opportunity to identify the nutritional factors and underlying genetic and molecular mechanisms that characterize human T2DM.

Palm fruit juice (PFJ) containing oil palm phenolics is obtained as a by-product from oil palm (Elaeis guineensis) fruit milling. It contains shikimic acid, soluble fibre and various phenolic acids including p-hydroxybenzoic acid and three caffeoylshikimic acid isomers. PFJ has also demonstrated beneficial health properties in various biological models. Increasing concentrations of PFJ and different PFJ fractions were used to assess growth dynamics and possible anti-ageing properties in fruit flies (Drosophila melanogaster) genotype w. Microarray gene expression analysis was performed on whole fruit fly larvae and their fat bodies, after the larvae were fed a control Standard Brandeis Diet (SBD) with or without PFJ. Transcripts from Affymetrix GeneChips were utilised to identify the possible mechanisms involved, with genes having fold changes > |1.30| and p < 0.05 considered differentially expressed. PFJ dose-dependently delayed larval growth and pupation, but not percent eclosion from pupae. Eclosed male fruit flies fed PFJ or its fractions during the larval stage tended to have 20-40% improved survival ratings over controls when allowed to age on the control diet (SBD). Microarray analysis of whole fruit fly larvae revealed that 127 genes were up-regulated, while 67 were down-regulated by PFJ. Functional analysis revealed transport and metabolic processes were up-regulated, while development and morphogenesis processes, including the nutrient-sensing Tor gene, were down-regulated by PFJ, whereas microarray analysis of larval fat bodies found 161 genes were up-regulated, while 84 genes were down-regulated. Genes involved in defence response and determination of adult lifespan, including those encoding various heat shock proteins and the antioxidant enzyme Sod2, were up-regulated, while cell cycle and growth genes were down-regulated. Thus, PFJ supplementation lengthened the growth stages in fruit fly larvae that was reflected in extended ageing of adult flies, suggesting that larval expression of hormetic stress response genes was linked to subsequent ageing and longevity.