The Effect of Dietary Addition of a Synbiotic After Long-Term Starvation on Certain Biochemical Parameters and Liver Structure in Common Carp (Cyprinus Carpio L.)

The prolonged starvation has many effects on the physiological and morphological processes in fish and interferes them with the ability to absorb nutrients and caloric intake. The aim of present study was to investigate the effect of long-term starvation and posterior dietary administration of commercial synbiotic consisting fructoligosaccharide (FOS) which used in combination with Enterococcus, Lactobacillus, Bifidobacterium and Lactococcus spp. for evaluation on some blood biochemical parameters and histological characteristics of common carp liver. Experimental fish after 5 months starvation period were subjected to the following feeding protocols: continuous starvation until 60 day (ST), re-feeding (FS) with dry composed diet (Aqua 1032 Swim) and refeeding with composed diet and synbiotic (FSS) for the following 60 days. Blood samples were used for analysis of the following plasma parameters: total protein, albumin, globulin, urea, creatinine, cholesterol, AST, ALT, glucose and serum for thyroid hormones. Histology analyses were performed on the carp liver samples. During the experimental period, fasting and refeeding were influenced significant on studied biochemical parameters, except glucose and urea. Also, the statistically largest (P <0.001) difference was observed in albumin and cholesterol values after refeeding. Our results reveal the changes in values of biochemical parameters during long-term starvation and refeeding with synbiotic and indicate signs of structural alterations of the liver in common carp.

Effect of short-term fasting on the expression of ACTH (cMC2) receptor in the adrenal glands of chicken (Gallus domesticus)

<b>Domestic hen is a full model in terms of stress and adrenal function. The main hormone produced by the hens’ adrenals is corticosterone, synthesized and secreted by stimulating the HPA axis during stress. Direct activation of adrenal activity is conditioned by ACTH, which binds to the melanocortin receptor cMC2 in adrenals. It stimulates the synthesis and release of corticosterone. One of the factors that stimulate the HPA axis activity is the starvation, to which the hen is very sensitive. The purpose of this study was to determine the ACTH receptor cMC2 expression in the hens’ adrenals during the short-term fasting and after restoring the proper level of nutrition (refeeding). The results of the experiment show that 24-hour of food deprivation is stressful for the hen, as indicated by increased concentrations of corticosterone in the adrenals and in blood plasma. Changes in cMC2R expression and level of corticosterone in the adrenals during fasting and refeeding indicate a rapid increase of HPA axis activity in response to differentiated levels of nutrition. The results of this experiment confirm the direct effect of ACTH on the avian adrenals in corticosterone release.

Innate Immune Response to Fasting and Refeeding in the Zebrafish Kidney

Animals acquire nutrients and energy through feeding to achieve a balance between growth and organismal health. When there is a change in nutrient acquisition, the state of growth changes and may also cause changes in the intrinsic immune system. Compensatory growth (CG), a specific growth phenomenon, involves the question of whether changes in growth can be accompanied by changes in innate immunity. The zebrafish (Danio rerio), a well-known fish model organism, can serve as a suitable model. In this study, the zebrafish underwent 3 weeks of fasting and refeeding for 3 to 7 day periods. It was found that CG could be achieved in zebrafish. Zebrafish susceptibility to Streptococcus agalactiae increased after starvation. In addition, the amount of melano-macrophage centers increased after fasting and the proportion of injured tubules increased after refeeding for 3 and 5 days, respectively. Furthermore, the kidneys of zebrafish suffering from starvation were under oxidative stress, and the activity of several antioxidant enzymes increased after starvation, including catalase, glutathione peroxidases and superoxide dismutase. Innate immune parameters were influenced by starvation. Additionally, the activity of alkaline phosphatase and lysozyme increased after starvation. The mRNA expression of immune-related genes like il-1β was elevated to a different extent after fasting with or without lipopolysaccharides (LPS) challenge. This study showed that the function of the innate immune system in zebrafish could be influenced by nutrition status.

How Far Are We from Prescribing Fasting as Anticancer Medicine?

(1) Background: the present review provides a comprehensive and up-to date overview of the potential exploitation of fasting as an anticancer strategy. The rationale for this concept is that fasting elicits a differential stress response in the setting of unfavorable conditions, empowering the survival of normal cells, while killing cancer cells. (2) Methods: the present narrative review presents the basic aspects of the hormonal, molecular, and cellular response to fasting, focusing on the interrelationship of fasting with oxidative stress. It also presents nonclinical and clinical evidence concerning the implementation of fasting as adjuvant to chemotherapy, highlighting current challenges and future perspectives. (3) Results: there is ample nonclinical evidence indicating that fasting can mitigate the toxicity of chemotherapy and/or increase the efficacy of chemotherapy. The relevant clinical research is encouraging, albeit still in its infancy. The path forward for implementing fasting in oncology is a personalized approach, entailing counteraction of current challenges, including: (i) patient selection; (ii) fasting patterns; (iii) timeline of fasting and refeeding; (iv) validation of biomarkers for assessment of fasting; and (v) establishment of protocols for patients’ monitoring. (4) Conclusion: prescribing fasting as anticancer medicine may not be far away if large randomized clinical trials consolidate its safety and efficacy.

Reducing hepatic PKD activity lowers circulating VLDL cholesterol

Protein kinase D (PKD) is emerging as an important kinase regulating energy balance and glucose metabolism; however, whether hepatic PKD activity can be targeted to regulate these processes is currently unclear. In this study, hepatic PKD activity was reduced using adeno-associated virus vectors to express a dominant-negative (DN) version of PKD1, which impairs the action of all three PKD isoforms. In chow-fed mice, hepatic DN PKD expression increased whole-body glucose oxidation, but had only mild effects on glucose and insulin tolerance and no effects on glucose homeostasis following fasting and refeeding. However, circulating VLDL cholesterol was reduced under these conditions and was associated with hepatic fatty acid accumulation, but not lipids involved in lipoprotein synthesis. The limited effects on glucose homeostasis in DN PKD mice was despite reduced expression of gluconeogenic genes under both fasted and refed conditions, and enhanced pyruvate tolerance. The requirement for PKD for gluconeogenic capacity was supported by in vitro studies in cultured FAO hepatoma cells expressing DN PKD, which produced less glucose under basal conditions. Although these pathways are increased in obesity, the expression of DN PKD in the liver of mice fed a high-fat diet had no impact on glucose tolerance, insulin action, pyruvate tolerance or plasma VLDL. Together, these data suggest that PKD signalling in the liver regulates metabolic pathways involved in substrate redistribution under conditions of normal nutrient availability, but not under conditions of overnutrition such as in obesity.

A Pilot Study on the Effects of Medically Supervised, Water-Only Fasting and Refeeding on Cardiometabolic Risk

The Fasting for Brain and Heart Health Study was a prospective, single-center, observational study examining the effects of medically supervised, water-only fasting followed by an exclusively whole-plant-food refeeding diet on accepted measures of cardiovascular risk and metabolic health. The study enrolled 48 overweight/obese, non-diabetic participants of which 26 completed the full study protocol. The participants fasted according to an established protocol at an independent medical center that reported mean fast and refeed lengths of 17 and 7 days, respectively. The primary endpoint was to describe mean glucose tolerance as indicated by Homeostatic Model Assessment of Insulin Resistance (HOMA-IR) scores at baseline, end-of-fast (EOF), and end-of-refeed (EOR) visits. Secondary endpoints were to describe the effects of fasting and refeeding on accepted markers of cardiovascular risk. Here we show that medically supervised, water-only fasting and/or whole-plant-food refeeding reduced resting systolic blood pressure (SBP), abdominal circumference, low-density lipoprotein (LDL), and high-sensitivity C-reactive protein (hsCRP) after refeeding. An increase in HOMA-IR scores at EOR was also observed.