Our data indicate that feeding of male Wistar rats with a high carbohydrate normocaloric diet results in a substantial development of obesity. Moreover, exposure of juvenile individuals to obesogenic environment leads, after a certain "latent period", to the development of obesity that may reflect low protein content of used liquid diet or higher resistance of juvenile organism to the obesogenic factors. Finally, based on the data obtained we suggest that Fresubin, with respect to its properties, may serve as a diet for the development of obesity which may exemplify an "obesity model" applicable in small laboratory animals.

No abstract

We have previously described the development of substantial, but reversible obesity in Wistar rats fed with palatable liquid nutrition (Fresubin). In this study, we investigated changes in serum hormone levels, glycemia, fat mass, adipocyte size, and gene expression of adipokines and inflammatory markers in adipose tissue of Wistar rats fed by Fresubin (i) for 5 months, (ii) up to 90 days of age, or (iii) after 90 days of age to characterize metabolic alterations and their reversibility in rats fed with Fresubin. An intra-peritoneal glucose tolerance test was also performed to determine levels of serum leptin, adiponectin, insulin, and C-peptide in 2- and 4-month-old animals. In addition, mesenteric and epididymal adipose tissue weight, adipocyte diameter, and gene expression of pro- and anti-inflammatory adipokines and other markers were determined at the end of the study. Chronic Fresubin intake significantly increased adipocyte diameter, reduced glucose tolerance, and increased serum leptin, adiponectin, insulin, and C-peptide levels. Moreover, gene expression of leptin, adiponectin, CD68, and nuclear factor kappa B was significantly increased in mesenteric adipose tissue of Fresubin fed rats. Monocyte chemotactic protein 1 messenger RNA (mRNA) levels increased in mesenteric adipose tissue only in the group fed Fresubin during the entire experiment. In epididymal adipose tissue, fatty acid binding protein 4 mRNA levels were significantly increased in rats fed by Fresubin during adulthood. In conclusion, chronic Fresubin intake induced complex metabolic alterations in Wistar rats characteristic of metabolic syndrome. However, transition of rats from Fresubin to standard diet reversed these alterations.

Abstract.We determined the effect of chronic liquid nutrition (Fresubin) intake in different developmental stages on the cardiovascular and renal system of male Wistar rats. Body weight, water intake and blood pressure were periodically measured. Selected serum and urine biochemical parameters reflecting metabolic and homeostatic changes after Fresubin intake were investigated as well. Heart and kidney weight, diameter of cardiomyocytes, diameter and length of cardiomyocyte nuclei, wall thickness of thoracic aorta, the diameter and the area of renal corpuscles and serum and urine biochemical parameters were assessed at the end of experiment. We showed that Fresubin intake differently affects the investigated morphological and biochemical parameters in rats and this effect was dependent on the developmental stage when Fresubin was provided. Importantly, we have shown that Fresubin-induced elevation of blood pressure is a reversible phenomenon and it is independent of weight gain and subsequent development of obesity.

Experimental and clinical studies have shown alterations in activity of systems responsible for neuroendocrine stress response in obese individuals. therefore we investigated the effect of palatable normocaloric liquid nutrition (fresubin) on alterations in activity of the hypothalamic-pituitary-adrenal (HPa) axis in male Wistar rats of different developmental stages. control rats (con) received standard pellet chow all the time from weaning (21 st day of age) to 150 days. fresubin was administered throughout the experiment (ln), only in juvenility (from 21 st to 90 th day of age; lnJ) or only in adulthood (from 90 th to 150 th day of age; lna). body weight and energy intake were periodically monitored. adrenal gland and fat tissue weight and plasma corticosterone levels (CORT) was determined after sacrification. Fresubin intake induced obesity in ln and lna rats. in ln and lna rats were observed elevated serum cort levels, but only in LN rats with significant twofold increase compared to LNJ rats. However, the weight of adrenal glands did not differ between ln, lnJ and lna experimental groups. based on our results, we suggest, that obesity induced by fresubin in ln and lna rats is accompanied by increased HPa activity represented by elevated plasma cort levels in these rats.