Chow Pellets Research Articles

Effect of Feeding Enriched Mutton on Blood Lipid-Mineral Parameters and Cardio Vessel Changes in Male Sprague-Dawley Rats

Sixty male Sprague-Dawley rats aged six to seven months were allotted randomly into five groups of 12 animals each to evaluate the effects of mutton with altered fatty acid profiles on blood plasma lipid parameters and aortic intima changes. The five experimental diets were, the oil palm frond (OPF) meat pellet (from sheep fed 80% OPF+20% (% w/w) commercial concentrate), HAF meat pellet (from sheep fed 50% OPF+50% (% w/w) commercial concentrate), COC meat pellet (from sheep fed 100% commercial concentrate), COM meat pellet (prepared using commercially available mutton as its ingredient) and CON (standard rat chow pellet fed as the control group). The feeding trial lasted for 6 weeks. Blood and arterial tissue samples were obtained at two, four and six weeks after the onset of the trial. Results showed that COC increased the rat serum HDL-Cholesterol significantly (P<0.05) compared to CON group at different weeks of sampling. Conversely, CON had the highest triglyceride value among the treatments at 6th week of feeding. The results on arterial lesions were inconclusive. It is concluded that meat-based diets could raise serum HDL- Cholesterols in rats compared to a plant-based standard rat chow diet.

The first of the viscoceuticals? A shear thickening gum induces gastric satiety in rats.

We examined the effect of gavage of 4 ml of a viscous shear-thickening polysaccharide solution (15% w/w) extracted from the fronds of the mamaku tree fern (Cythea medullaris) in reducing appetite and delaying gastric emptying in twenty six Sprague Dawley rats. After two weeks habituation to a pelleted chow, the rats were gavaged on alternate days with either the mamaku extract or with the same volume of deionised water for a total of five times over a period of two weeks. The body mass and food intake of each rat were determined daily and the weights of their stomach contents determined on euthanasia two hours after the final gavage. The rats gavaged with the mamaku gum consumed significantly lower quantities of chow on the day of gavage. The weights of the stomach contents of rats two hours after gavage with mamaku extract were significantly greater than those following gavage with water. The failure of the rats dosed with mamaku to lose body weight likely resulted from the overall adverse effect of gavage on food intake, the limited numbers of doses of the gum and the rebound hyperphagia on days when the rats were not gavaged. Together the results indicate that gavage with mamaku gum delayed gastric emptying with respect to that of rats dosed with water and supressed appetite for 12-24 hours after dosage.

Expression of liver alpha-amylase in obese mouse hepatocytes.

The aim of this study is to demonstrate the relation between the expression of liver alpha-amylase and obesity. Alpha-amylase catalyses the hydrolysis of 1, 4-alpha-glucosidic linkages in polysaccharides and has three main subtypes, including: salivary, pancreatic, and hepatic. Hepatic alpha-amylase is involved in glycogen metabolism, and has a role in obesity and its management. In this study, we aimed to analyze the expression of liver alpha-amylase in overweight and obese mouse. In this study, NMRI male mice were randomly divided into two groups. The sample group (obese) took a high-fat and carbohydrate diet, while the control group (normal) took a laboratory pellet chow for eight weeks. During this period, their weight was measured. After eight weeks, liver hepatocytes were isolated using an enzymatic digestion method. Immunocytochemistry (ICC) and flow cytometry analysis were performed to measure alpha amylase protein expression in mouse liver hepatocyte cells. A significant difference in the body weight was observed between the two groups (p<0.05). The qualitative protein expression of liver alpha-amylase was found to be higher in the obese group in both tests (immunocytochemistry and flow cytometry). Animals from the test group presented higher alpha-amylase expression, which suggests that this hepatic protein may constitute a potential indicator of susceptibility for fat tissue accumulation and obesity. The present data demonstrates an increased expression of liver amylase in obese mice. These results suggest that liver amylase secretion might be useful for predicting susceptibility to obesity induced by consumption of a high-fat and carbohydrate diet.

A test of the reward-value hypothesis.

Rats retain source memory (memory for the origin of information) over a retention interval of at least 1week, whereas their spatial working memory (radial maze locations) decays within approximately 1day. We have argued that different forgetting functions dissociate memory systems. However, the two tasks, in our previous work, used different reward values. The source memory task used multiple pellets of a preferred food flavor (chocolate), whereas the spatial working memory task provided access to a single pellet of standard chow-flavored food at each location. Thus, according to the reward-value hypothesis, enhanced performance in the source memory task stems from enhanced encoding/memory of a preferred reward. We tested the reward-value hypothesis by using a standard 8-arm radial maze task to compare spatial working memory accuracy of rats rewarded with either multiple chocolate or chow pellets at each location using a between-subjects design. The reward-value hypothesis predicts superior accuracy for high-valued rewards. We documented equivalent spatial memory accuracy for high- and low-value rewards. Importantly, a 24-h retention interval produced equivalent spatial working memory accuracy for both flavors. These data are inconsistent with the reward-value hypothesis and suggest that reward value does not explain our earlier findings that source memory survives unusually long retention intervals.

Kolaviron, a biflavonoid of Garcinia kola seed mitigates ischemic/reperfusion injury by modulation of pro-survival and apoptotic signaling pathways.

The study was designed to investigate the ameliorative effect of Kolaviron (KV) on ischemic/reperfusion injury in experimental animal models. Male Wistar rats were randomly divided into two groups: Group 1 received corn oil as a vehicle and rats in Group 2 were administered KV at 200 mg/kg for 4 weeks. The rats were fed with rat standard chow pellet and water administered ad libitum. After 4 weeks of KV administration, hearts were excised and mounted on the working heart perfusion system. Western blot analysis for protein expression was carried out on frozen heart samples. There was significant (P < 0.05) reduction in the activity of catalase, superoxide dismutase, and glutathione peroxidase with concomitant reduction in oxygen radical absorbance capacity in ischemic rat heart of control compared to group pre-treated with KV, respectively. Similarly, intracellular reactive oxygen species and malondialdehyde were significantly elevated in control compared to KV pre-treated rats. KV significantly increased total Akt/protein kinase B (PKB), phosphorylated Akt/PKB at serine 473 and also caused a significant reduction in p38 mitogen-activated protein kinase, Caspase 3, and cleaved poly adenosine diphosphate ribose polymerase. Taken together, KV offered significant cardioprotection via free radical scavenging activity and upregulation of pro-survival pathway.

Incubation of food craving is independent of macronutrient composition.

Cues previously paired with rewarding stimuli induce a time-dependent increase in the motivational craving state (incubation of craving). Whether there is an increase in craving for high-fat (HF) food over time, which may contribute to overeating and obesity, has not been determined. We hypothesized that cues paired with HF pellets would elicit a greater incubation of craving effect than those paired with standard chow (SC) pellets. Rats exposed to cues associated with either HF or SC pellets demonstrated equivalent levels of craving over an abstinence period of 30 days. Diet preference tests between SC pellets and LabDiet revealed that SC pellets were preferred over LabDiet. Rats reared on SC pellets exclusively, did not display incubation of craving for SC pellets, suggesting that prior history with the food plays an important role in cue-induced seeking behavior. Results identified cues previously associated with food undergo a comparable magnitude of incubation of craving. When ingestive behavior was measured after 30 days of abstinence, rats significantly increased their consumption of HF pellets. Our results indicate that food cues gain importance over time, trigger increased approach behaviors, and increased consumption of HF food following abstinence. This may contribute to overeating and the development of obesity.

Moving evidence into practice: cost analysis and assessment of macaques' sustained behavioral engagement with videogames and foraging devices.

Environmental enrichment plans for captive nonhuman primates often include provision of foraging devices. The rationale for using foraging devices is to promote species-typical activity patterns that encourage physical engagement and provide multi-sensory stimulation. However, these devices have been shown to be ineffective at sustaining manipulation over long periods of time, and often produce minimal cognitive engagement. Here we use an evidence-based approach to directly compare the amount of object-directed behavior with a foraging device and a computer-based videogame system. We recorded 11 adult male rhesus monkeys' interactions with a foraging device and two tasks within a joystick videogame cognitive test battery. Both techniques successfully produced high levels of engagement during the initial 20 min of observation. After 1 hr the monkeys manipulated the foraging device significantly less than the joystick, F(2,10) = 43.93, P < 0.0001. Subsequent testing showed that the monkeys engaged in videogame play for the majority of a 5 hr period, provided that they received a 94 mg chow pellet upon successful completion of trials. Using a model approach, we developed previously as a basis for standardized cost:benefit analysis to inform facility decisions, we calculated the comprehensive cost of incorporating a videogame system as an enrichment strategy. The videogame system has a higher initial cost compared to widely-used foraging devices, however, the ongoing labor and supply costs are relatively low. Our findings add to two decades of empirical studies by a number of laboratories that have demonstrated the successful use of videogame-based systems to promote sustained non-social cognitive engagement for macaques. The broader significance of the work lies in the application of a systematic approach to compare and contrast enrichment strategies and encourage evidence-based decision making when choosing an enrichment strategy in a manner that promotes meaningful cognitive enrichment to the animals.

Effect of chronic intake of liquid nutrition on stomach and duodenum morphology

Changes in the quantity and/or quality of food intake have been shown to be associated with morphological and functional alterations of the gastrointestinal system. To examine this, we investigated the effect of chronic liquid nutrition intake (Fresubin) on stomach and duodenum morphology in Wistar rats fed liquid nutrition during different developmental periods. We used four groups of rats: a) control group (CON) fed pelleted chow for 130days; b) liquid nutrition group (LN) fed liquid nutrition for 130days; c) liquid nutrition juvenile group (LNJ) fed liquid nutrition for 70days and then pelleted food for 60days; d) liquid nutrition adult group (LNA) fed pelleted chow for 70days and then liquid nutrition for 60days. We found that LN and LNA rats showed a significant reduction of empty stomach mass compared to CON animals, while stomach and duodenal longitudinal muscle layer thickness did not differ between groups. Villus height was increased only in LNA animals, while villus width was increased in both LN and LNA rats. Crypt depth was reduced in LNJ. However, liquid nutrition intake did not affect villus height/crypt depth ratio, nor number of goblet cells. We found that chronic intake of liquid nutrition affects some morphological parameters of the stomach and duodenum but these changes were not homogenous between experimental groups. Interestingly, transition from liquid nutrition to solid food reversed the alterations of stomach weight as well as villus width induced by intake of liquid nutrition in LNA rats. Our data indicate that morphological and functional changes in the gastrointestinal system induced by qualitative and quantitative changes in food intake are at least partially reversible. Therefore, specific diets may be used potentially as adjuvant treatment for modulating the progression of gastrointestinal diseases by affecting stomach and small intestine morphology.

Evaluation of the Effect of &amp;lt;i&amp;gt;Gurusa&amp;lt;/i&amp;gt;, a Ugandan Cereal-Based Fermented Food on Serum Lipid Profile and Body Weight of Wistar Albino Rats

The effect of Gurusa, a fermented traditional food on lipid profile and body weight was investigated. Thirty male albino rats weighing between 75 - 115 g assigned into five study groups designated A to E (n = 6) were fed 20 g of prepared pellets and tap water given ad libitum. The animals were served graded doses of Gurusa. Group A was served 100% rat chow pellets (made of maize bran); groups B, C and D were given pellets of 75% rat chow and 25% Gurusa, 50% rat chow and 50% Gurusa, 25% rat chow and 75% Gurusa respectively while group E was served 100% Gurusa. The lipid profile showed a dose dependent effect of Gurusa administration as one moves down the groups. Group D had a reverse action of group B and showed significant (P < 0.05) increase in TC, TG and HDL compared to groups A and B but a significant (P < 0.05) decrease in LDL compared to group B. Weight changes in group B produced a significant (P < 0.05) increase in MWI and GR compared to the other groups. There was no significant (P ≥ 0.05) difference in MWI and GR of group D when compared with group A. However group C showed significant (P < 0.05) increase in MWI and GR when compared with group A. Gurusa consumption alters both lipid profile and body weight and its combination with maize bran or other foods rich in dietary fibre, have potential to serve therapeutic purposes in the prevention of atherosclerosis and obesity depending on the intended objective.

PATHOPHYSIOLOGICAL CHANGES IN LIVER TISSUES OF HYPERCALORIE DIET-INDUCED OBESE RATS

ABSTRACTObjectives: Hypercalorie diet intake has been associated with many long-term complications including metabolic syndrome, cardiovascular diseases,and nonalcoholic fatty liver disease.Methods: A total of 12 Wistar rats either sex were used in this study. These animals were randomly divided into two groups as control and obese rats.Group 1 consists of six rats weighing 150-200 g and fed with normal pellet chow. Another six rats were fed hypercalorie/cafeteria diet to induce obesity andincluded in the study after 19 weeks of age. All animals were sacrificed; liver tissues were collected, weighed and sent for the histopathological examination.Results: Weight of liver tissues of was significantly more in obese rats than the control rats. Histopathological examination shows an excessive fatdeposition and sinusoidal congestion in the liver tissues of obese rats.Conclusion: Increase in body weight is associated with the increase in fat deposition in the liver tissues which further develops into inflammationand necrosis of liver cells.Keywords: Wistar rats, Hypercalorie/cafeteria diet, Obese rats, Histopathological examination.

Abolition of lemniscal barrellette patterning in Prrxl1 knockout mice: Effects upon ingestive behavior

Ingestive behaviors in mice are dependent on orosensory cues transmitted via the trigeminal nerve, as confirmed by transection studies. However, these studies cannot differentiate between deficits caused by the loss of the lemniscal pathway vs. the parallel paralemniscal pathway. The paired-like homeodomain protein Prrxl1 is expressed widely in the brain and spinal cord, including the trigeminal system. A knockout of Prrxl1 abolishes somatotopic barrellette patterning in the lemniscal brainstem nucleus, but not in the parallel paralemniscal nucleus. Null animals are significantly smaller than littermates by postnatal day 5, but reach developmental landmarks at appropriate times, and survive to adulthood on liquid diet. A careful analysis of infant and adult ingestive behavior reveals subtle impairments in suckling, increases in time spent feeding and the duration of feeding bouts, feeding during inappropriate times of the day, and difficulties in the mechanics of feeding. During liquid diet feeding, null mice display abnormal behaviors including extensive use of the paws to move food into the mouth, submerging the snout in the diet, changes in licking, and also have difficulty consuming solid chow pellets. We suggest that our Prrxl1−/− animal is a valuable model system for examining the genetic assembly and functional role of trigeminal lemniscal circuits in the normal control of eating in mammals and for understanding feeding abnormalities in humans resulting from the abnormal development of these circuits.

Effect of carbonated drinks on wound healing of oral epithelium

BackgroundCarbonated drinks are the second most consumed non-alcoholic beverages in the world after tea. The effects of these drinks on hard tissues and vital organs of the body have been proved beyond doubt. This study, however, explains the effect of these drinks on wound healing of oral epithelium. MethodsThirty-six male Wistar rats were considered for the study. A circular wound of 3.0mm was created on the buccal mucosa of all animals and they were divided into two groups. Animals in group 1 were fed with chow pellet and water, while those in group 2 were fed with a commercially available carbonated drink instead of water. Six animals from each group were euthanized at 0, 7, and 21 days. Wound site was histologically assessed for differences in thickness and characteristics of the regenerating epithelium between two groups. ResultsThere was a marked difference in the healing pattern between the two groups. Animals in group 1 showed a normal healing pattern at the end of day 21. In the group 2, the regenerated epithelium showed hyperplasia and hyperkeratosis along with acanthosis at the end of the experiment with a subsequent delayed inflammatory reaction at day 21. ConclusionConsumption of carbonated drinks can disrupt oral wound healing. The contents in carbonated drinks have a proinflammatory action on the soft tissue. Results suggest that epithelial changes seen in experimental group 2 could be a result of constant irritation by the acidic and fizzy nature of carbonated drinks.

HISTOLOGICAL EFFECTS OF CARBONATED DRINKS ON ORAL SUBMUCOSAL HEALING IN ALBINO WISTA RATS

Objective: In this study the effects of carbonated drinks on the healing process of oral submucosa of albino wistar rats were evaluated.&#x0D; Design: This study comprised of 24 adult albino wistar rats which were randomly assigned to a experimental group 1 and an experimental group 2. A circular wound of 3.0 mm was created on the buccal mucosa of each albino wistar rat at day 0. Animals in control group were fed with chow pellet and water while those in experimental group were fed with chow pellet and a commercially available carbonated drink instead of water. 6 animals from each group were sacrificed by decapitation under deep anesthesia at day 7 and 21. The tissue dissected from buccal area was serially sectioned and stained with Haematoxylin &amp; Eosin stains. Wound site was histologically assessed for differences in the healing pattern of submucosa; inflammatory cell count and neovascularization between two groups.&#x0D; Results: There was a marked difference in the healing pattern between the two groups. Animals in group-1 showed a normal healing pattern with formation of a fibrous connective tissue at the end of day-21. In the group-2, there is altered healing phenomenon at the end of the experiment with a subsequent delayed inflammatory reaction at day-21&#x0D; Conclusion: These findings suggest that consumption of carbonated drinks can disrupt oral wound healing. The contents in carbonated drinks have a proinflammatory action on the soft tissue.

Ceftriaxone and cefazolin attenuate the cue-primed reinstatement of alcohol-seeking.

Alcohol consumption and the reinstatement of alcohol-seeking rely on glutamate and GABA transmission. Modulating these neurotransmitters may be a viable treatment strategy to prevent alcohol relapse. N-acetylcysteine (NAC) and the antibiotic ceftriaxone (CEF) alter the glial reuptake and release of glutamate while the antibiotic cefazolin (CEFAZ) modulates GABA signaling without affecting glutamate. Here, we used the extinction-reinstatement model of relapse to test the ability of these compounds to attenuate the reinstatement of alcohol-seeking. Male Sprague-Dawley rats were trained to self-administer 20% (v/v) alcohol in the home cage using an intermittent schedule (24 h on, 24 h off) for 12 sessions. Subsequently, animals self-administered alcohol during daily 45-min operant sessions for 26 sessions, followed by extinction training. We tested whether chronic administration of NAC, CEF, or CEFAZ attenuated the cue-primed reinstatement of alcohol-seeking. CEF and CEFAZ attenuated cue-primed reinstatement of alcohol-seeking while NAC had no effect. We subsequently investigated whether CEF and CEFAZ alter the self-administration of sucrose and chow pellets and if CEFAZ attenuates the reinstatement of cocaine-seeking. The operant self-administration of regular chow and sucrose was not altered by either CEF or CEFAZ. CEFAZ had no effect on cocaine reinstatement, a behavior that has been strongly tied to altered glutamate homeostasis in the nucleus accumbens. Thus the ability of CEFAZ to attenuate alcohol reinstatement likely does not involve the glial modulation of glutamate levels. The dampening of GABA transmission may be a common mechanism of action of cefazolin and ceftriaxone.

Exaggerated activity of HPA axis in obese rats fed normocaloric liquid nutrition.

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 (21st day of age) to 150 days. Fresubin was administered throughout the experiment (LN), only in juvenility (from 21st to 90th day of age; LNJ) or only in adulthood (from 90th to 150th 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.

Liquid diet induces memory impairment accompanied by a decreased number of hippocampal neurons in mice

It is suggested that masticatory dysfunction affects the central nervous system; however, the underlying mechanism remains unknown. Brain-derived neurotrophic factor (BDNF) and its receptor, TrkB, are known to play important roles in memory and learning. In this study, we examined the effects of mastication on memory, the expression levels of BDNF and TrkB, and the number of neurons in the hippocampus of mice. Male C57 BL/6J mice (3 weeks old) were randomly divided into the control group (N = 7) fed chow pellets and the experimental group (N = 7) fed a liquid diet, which reduces mastication during eating. At 14 weeks of age, we performed a passive avoidance test and found that memory and learning ability were impaired in the experimental group compared with the control group. After the behavioral experiment, brains were harvested and analyzed morphologically and biochemically. In the hippocampus of the experimental group, the expression levels of BDNF were significantly higher, whereas those of TrkB were lower than those of the control group. In the cerebral cortex, these levels remained unchanged between the two groups. The ratio of phospho-p44/42 ERK/pan ERK, a downstream molecule of BDNF/TrkB signaling, in the experimental group was significantly lower than that of the control group in the cortex and hippocampus. The number of pyramidal neurons in the hippocampus was lower in the experimental group than in the control group. These findings suggest that reduced mastication induced by a liquid diet in early childhood may impair memory and learning ability, accompanied by neuronal loss in the hippocampus.

Meal Duration as a Measure of Orofacial Nociceptive Responses in Rodents

A lengthening in meal duration can be used to measure an increase in orofacial mechanical hyperalgesia having similarities to the guarding behavior of humans with orofacial pain. To measure meal duration unrestrained rats are continuously kept in sound attenuated, computerized feeding modules for days to weeks to record feeding behavior. These sound-attenuated chambers are equipped with chow pellet dispensers. The dispenser has a pellet trough with a photobeam placed at the bottom of the trough and when a rodent removes a pellet from the feeder trough this beam is no longer blocked, signaling the computer to drop another pellet. The computer records the date and time when the pellets were taken from the trough and from this data the experimenter can calculate the meal parameters. When calculating meal parameters a meal was defined based on previous work and was set at 10 min (in other words when the animal does not eat for 10 min that would be the end of the animal's meal) also the minimum meal size was set at 3 pellets. The meal duration, meal number, food intake, meal size and inter-meal interval can then be calculated by the software for any time period that the operator desires. Of the feeding parameters that can be calculated meal duration has been shown to be a continuous noninvasive biological marker of orofacial nociception in male rats and mice and female rats. Meal duration measurements are quantitative, require no training or animal manipulation, require cortical participation, and do not compete with other experimentally induced behaviors. These factors distinguish this assay from other operant or reflex methods for recording orofacial nociception.

Meal Duration as a Measure of Orofacial Nociceptive Responses in Rodents

A lengthening in meal duration can be used to measure an increase in orofacial mechanical hyperalgesia having similarities to the guarding behavior of humans with orofacial pain. To measure meal duration unrestrained rats are continuously kept in sound attenuated, computerized feeding modules for days to weeks to record feeding behavior. These sound-attenuated chambers are equipped with chow pellet dispensers. The dispenser has a pellet trough with a photobeam placed at the bottom of the trough and when a rodent removes a pellet from the feeder trough this beam is no longer blocked, signaling the computer to drop another pellet. The computer records the date and time when the pellets were taken from the trough and from this data the experimenter can calculate the meal parameters. When calculating meal parameters a meal was defined based on previous work and was set at 10 min (in other words when the animal does not eat for 10 min that would be the end of the animal's meal) also the minimum meal size was set at 3 pellets. The meal duration, meal number, food intake, meal size and inter-meal interval can then be calculated by the software for any time period that the operator desires. Of the feeding parameters that can be calculated meal duration has been shown to be a continuous noninvasive biological marker of orofacial nociception in male rats and mice and female rats. Meal duration measurements are quantitative, require no training or animal manipulation, require cortical participation, and do not compete with other experimentally induced behaviors. These factors distinguish this assay from other operant or reflex methods for recording orofacial nociception.

Investigation of Effect of Nutritional Drink on Chemotherapy-Induced Mucosal Injury and Tumor Growth in an Established Animal Model

Chemotherapy-induced mucositis represents a significant burden to quality of life and healthcare costs, and may be improved through enhanced nutritional status. We first determined the safety of two nutritional drinks (plus placebo), and then potential gut protection in tumor-bearing rats in a model of methotrexate-induced mucositis. In study 1, animals were fed one of two test diets (or placebo or control chow pellets) for a total of 60 days and were monitored daily. All diets were found to be safe to administer. In study 2, after seven days of receiving diets, a Dark Agouti Mammary Adenocarcinoma (DAMA) was transplanted subcutaneously. Ten days after starting diets, animals had 2 mg/kg intramuscular methotrexate administered on two consecutive days; after this time, all animals were given soaked chow. Animals were monitored daily for changes in bodyweight, tumor burden and general health. Animals were killed 10, 12 and 16 days after initially starting diets, and tissues were collected at necropsy. In study 1, animals receiving diets had gained 0.8% and 10.8% of their starting bodyweight after 60 days, placebo animals 4.4%, and animals fed on standard chow had gained 15.1%. In study 2, there was no significant influence of test diet on bodyweight, organ weight, tumor burden or biochemical parameters. Only animals treated with MTX exhibited diarrhea, although animals receiving Diet A and Diet C showed a non-significant increase in incidence of diarrhea. Administration of these nutritional drinks did not improve symptoms of mucositis.

Monosodium glutamate (MSG) consumption is associated with urolithiasis and urinary tract obstruction in rats.

BackgroundThe peritoneal injection of monosodium glutamate (MSG) can induce kidney injury in adult rats but the effects of long-term oral intake have not been determined.MethodsWe investigated the kidney histology and function in adult male Wistar rats that were fed ad libitum with a standard rat chow pellet and water with or without the addition of 2 mg/g body weight MSG/day in drinking water (n=10 per group). Both MSG-treated and control animals were sacrificed after 9 months when renal function parameters, blood and urine electrolytes, and tissue histopathology were determined.ResultsMSG-treated rats were more prone to kidney stone formation, as represented by the alkaline urine and significantly higher activity product of calcium phosphate. Accordingly, 3/10 MSG-treated rats developed kidney stones over 9 months versus none of the control animals. Further, 2/10 MSG-treated rats but none (0/10) of the controls manifested hydronephrosis. MSG-treated rats had significantly higher levels of serum creatinine and potassium including urine output volume, urinary excretion sodium and citrate compared to controls. In contrast, MSG-treated rats had significantly lower ammonium and magnesium urinary excretion.ConclusionOral MSG consumption appears to cause alkaline urine and may increase the risks of kidney stones with hydronephrosis in rats. Similar effects in humans must be verified by dedicated studies.