Commercial Rat Diet Research Articles

Ameliorative Potentials of Justicia Carnea and Cnidoscolus Aconitifolius on the Fecundity of Chloramphenicol-Induced Lymphoma Rats

Justicia carnea and Cnidoscolus aconitifolius were tested for their capacity to ameliorate the fecundity of chloramphenicol-induced lymphoma in rats. Seventy male Wistar rats weighing an average of 128g were randomly divided into 14 groups of five rats each. Group 1 was provided with commercial rat diet and water on a daily basis. For 28 days, rats in groups 2-14 received 250mg/kg bodyweight chloramphenicol by oral intubation. Group 2 received no therapy and is thus referred to as the negative control group. The remaining groups (3–14) received aqueous leaf extracts of J. carnea (ALEJC) (Groups 3-6), C. aconitifolius (ALECA) (Groups 7–10), or a combination of both extracts (Groups 11–14) at dosages of 500mg/kg, 1000mg/kg, 1500mg/kg, and 2000mg/kg, respectively, for 28 days. After anaesthesia with ether, blood was drawn from the retro-orbital venous plexus to determine the activities of oxidative stress indicators such as superoxide dismutase (SOD), catalase (CAT), malondialdehyde (MDA), and glutathione (GSH). The testes were dissected for histological inspection and the semen were collected for analysis. The results indicated a significant (p0.05) increase in weight across groups, as well as a reduction in sperm volume, viability, and motility in group 2 animals as compared to group 1. SOD and GSH levels increased significantly, but MDA levels increased in a non-significant (p>0.05) manner. The results indicated that the extracts had a beneficial impact on infertility associated with excessive chloramphenicol exposure.

Pomegranate Seed Extract: A Strong Antioxidant against Benign Prostatic Hyperplasia Induced Oxidative Stress in Albino Wistar Rats

Aim: The aim of this study was to assess the antioxidant properties of ethanolic and aqueous extracts of Punica granatum (Pomegranate) seed in testosterone induced benign prostate hyperplastic albino Wistar rats.
 Study design: This study is an interventional study.
 Place and Duration of Study: The experimental aspect of this study was conducted at the animal house, Department of Pharmacology, University of Port Harcourt between April and September, 2019.
 Methodology: Seventy (70) adult albino male wistar rats were used for this study. They were divided into 12 groups of 5 rats each and fed with commercial rat diet and clean drinking water. Aqueous and ethanolic extracts of Punica granatum seed were prepared using the maceration method. Benign Prostate Hyperplasia was induced in rats after they submitted to bilateral orchiectomy by daily injections of testosterone propionate (TP) (4 mg/kg b.wt.sc). Rats were treated with 500 or 1500 mg/kg b.wt. of aqueous or ethanoI extracts of Punica granatum seed, dutasteride or in combination. Administration of extracts was done by gavage. Plasma total oxidant status (TOS), total antioxidant status (TAS), superoxide dismutase (SOD) activity, were analyzed using sandwich ELISA Kits by Shanghai Korain Biotech Co., Ltd, China, while oxidative stress indices (OSI) were calculated. Statistical analysis was done using SPSS version 22.0 of Windows Stat Pac and p values less than 0.05 were considered statistically significant.
 Results: The results showed that the mean TOS, TAS, SOD and OSI for the rats in the normal control group were 1.66±0.2U/ml, 2.71±0.25U/ml, 41.8±2.9pg/ml and 0.62±0.10 respectively. After BPH induction (group 2), the values were 3.25±0.5U/ml,1.17±0.14U/ml, 23.38±2.09 pg/ml and 2.81±0.60pg/ml respectively. There were significant decreases for TOS and OSI, and significant increases for TAS and SOD when the rats where treated with lower and higher doses of both aqueous and ethanolic extracts of Punica granatum and Dutasteride.
 Conclusion: In conclusion, both doses of Punica granatum seed for ethanolic and aqueous extracts individually and in combination and with dutasteride markedly reduced total oxidant status, oxidative stress indices and improved the activities of antioxidant parameters like superoxide dismutase and total antioxidant status.

Assessment of Antioxidant Effects of Aqueous and Ethanolic Extracts of Zingiber officinale Rhizome in Testosterone Induced Benign Prostatic Hyperplasia Rat Model

Aims: To assess the antioxidant effects of the aqueous and ethanolic extracts of Ginger rhizome in testosterone induced prostate hyperplasic male rats.
 Study Design: The study was a cross-sectional study.
 Place and Duration of Study: The experimental aspect of this study was conducted at the animal house, Department of Pharmacology, University of Port Harcourt between April and September, 2019.
 Methodology: Sixty (60) adult albino male wistar rats were used for this study. They were divided into 12 groups of 5 rats each and fed with commercial rat diet and clean drinking water. Aqueous and ethanolic extractions of Ginger rhizome seed were prepared using the maceration method. BPH was induced in rats after they submitted to bilateral orchiectomy by daily injections of testosterone propionate (TP) (4 mg/kg b.wt.sc). Rats were treated with 500 or 1500 mg/kg b.wt. of aqueous or ethanoI extracts of Zingiber officinale (Zo) rhizome, dutasteride or in combination. Administration of extracts was done by gavage. Plasma total oxidant status (TOS), total antioxidant status (TAS), superoxide dismutase (SOD) activity, were analysed using sandwich ELISA Kits by Shanghai Korain Biotech Co., Ltd, China, while oxidative stress indices (OSI) were calculated. Statistical analysis was done using SPSS version 22.0 of Windows Stat Pac and p values <0.05 were considered statistically significant.
 Results: The results showed that exogenous induction of BPH in rats significantly increased (p=0.000) plasma TOS and OSI while TAS and SOD activities were reduced. However, 500 and 1500 mg/kg b.wt. of Zo rhizome administered orally after exogenous induction of BPH had been established for 15 days, significantly decreased (p=0.000) TOS, OSI and significantly improved the activities of antioxidant parameters like SOD and TAS. Non-significantly increased mean TAS and SOD were seen in a combination of both extracts with dutasteride, possibly suggestive of synergistic interaction between the herbs and the drug. Simultaneous administration of aqueous and ethanolic extracts of Zo rhizome with TP for 30 days also showed antioxidant qualities, although the effects were statistically not better than values for treatments done when BPH was established before treatment. Ethanolic extracts of Zo rhizome produced better antioxidant effects compared to the aqueous extracts.
 Conclusion: From the findings, we conclude that Zo rhizome can ameliorate oxidative stress and therefore may be beneficial in the management of benign prostatic hyperplasia.

Effects of Maternal Flaxseed Supplementation on Female Offspring of Diabetic Rats in Serum Concentration of Glucose, Insulin, and Thyroid Hormones.

Objective: This study aimed to evaluate the effect of maternal consumption of flaxseed flour and oil on serum concentrations of glucose, insulin, and thyroid hormones of the adult female offspring of diabetic rats. Methods: Wistar rats were induced to diabetes by a high-fat diet (60%) and streptozotocin (35mg/kg). Rats were mated and once pregnancy was confirmed, were divided into the following groups: Control Group (CG): casein-based diet; High-fat Group (HG): high-fat diet (49%); High-fat Flaxseed Group (HFG): high-fat diet supplemented with 25% flaxseed flour; High-fat Flaxseed Oil group (HOG): high-fat diet, where soya oil was replaced with flaxseed oil. After weaning, female pups (n=6) from each group were separated, received a commercial rat diet and were sacrificed after 180 days. Serum insulin concentrations were determined by ELISA, the levels of triiodothyronine (T3), thyroxine (T4) and thyroid-stimulating hormone (TSH) were determined by chemiluminescence. Results: There was a significant reduction in body weight at weaning in HG (-31%), HFG (-33%) and HOG (44%) compared to CG (p=0.002), which became similar by the end of 180 days. Blood glucose levels were reduced in HFG (-10%, p=0.044) when compared to CG, and there was no significant difference between groups in relation to insulin, T3, T4, and TSH after 180 days. Conclusions: Maternal severe hyperglycemia during pregnancy and lactation resulted in a microsomal offspring. Maternal consumption of flaxseed reduces blood glucose levels in adult offspring without significant effects on insulin levels and thyroid hormones.

The role of HMGB1 in liver inflammation in obese rats

ABSTRACTObesity is a chronic disease that is characterized by increased body fat owing to imbalance between consumed and expended energy. Inflammation generally is accompanied by accumulation of excess lipid in adipose tissue and liver. High mobility group box-1 (HMGB1) participates in the pathogenesis of inflammatory diseases. We investigated the relation of the number of HMGB1 positive cells to body mass index (BMI), liver inflammation and the number of Kupffer cells. We divided 18 female Wistar albino rats into two groups: group 1, untreated control fed normal commercial rat diet and group 2, obese rats fed a special diet containing 40% fat. The plasma concentrations of cholesterol, glucose, superoxide dismutase enzyme (SOD) and catalase activities were measured for all animals. The numbers of hepatocytes, Kupffer cells and HMGB1 positive cells were counted using stereological methods. The mean numbers of Kupffer cells and HMGB1 positive cells were higher for group 2 than for group 1. The concentrations of plasma cholesterol and glucose levels also were higher in group 2. Plasma levels of SOD and catalase were significantly lower in group 2 compared to group 1. The number of HMGB1 cells was related directly to BMI and inflammation. The role of HMGB1 was demonstrated for the liver of the obese group. We demonstrated the relations among HMGB1, BMI, obesity and inflammation.

A subchronic feeding study of dicamba-tolerant soybean with the dmo gene in Sprague–Dawley rats

The dicamba-tolerant soybean MON87708 expresses the dicamba mono-oxygenase (DMO) enzyme that is encoded by the dmo gene. In order to evaluate the safety of this soybean, a 90-day subchronic feeding toxicity study (13 weeks) was conducted on Sprague–Dawley rats. A total of 140 rats were divided into 7 groups (10/sex/group), including a standard commercial diet control group. The genetically modified (GM) soybean MON87708 and the near isogenic non-GM soybean A3525 were respectively processed to unhulled, full-fat, and heat-treated powder, then mixed into the diet at levels of 7.5%, 15%, and 30% (wt/wt) with the main nutrients of the various diets balanced and then fed to 6 groups. The remaining group of rats fed with a commercial rat diet served as blank control. Some isolated parameters indicated statistically significant differences in body weight, feed consumption/utilization, hematology, serum biochemistry, and relative organ weights. These differences were not consistent across gender or test-diet dose, which were attributed to incidental and biological variability. In conclusion, the results demonstrated that the transgenic soybean MON87708 containing DMO was as safe as non-transgenic isogenic counterpart with historical safe use.

Tocotrienol Attenuates Stress-Induced Gastric Lesions via Activation of Prostaglandin and Upregulation of COX-1 mRNA

The present study aims to distinguish the effect of tocotrienol on an important gastric protective factor, prostaglandin E2 (PGE2), in stress-induced gastric injury. Twenty-eight Wistar rats were divided into four groups of seven rats each. Two control groups were fed commercial rat diet, and two treatment groups were fed the same diet but with additional dose of omeprazole (20 mg/kg) or tocotrienol (60 mg/kg). After 28 days, rats from one control group and both treated groups were subjected to water-immersion restraint stress for 3.5 hours once. The rats were then sacrificed, their stomach isolated and gastric juice collected, lesions examined, and gastric PGE2 content and cyclooxygenase (COX) mRNA expression were determined. Both the regimes significantly attenuated the total lesion area in the stomach compared to the control. Gastric acidity, which was increased in stress, was significantly reduced in rats supplemented with omeprazole and tocotrienol. The PGE2 content was also significantly higher in the rats given tocotrienol supplementation compared to the control followed by an increase in COX-1 mRNA expression. We conclude that tocotrienol supplementation protected rat gastric mucosa against stress-induced lesions possibly by reducing gastric acidity and preserving gastric PGE2 by increasing COX-1 mRNA.

Suckling Rat Pups Accumulate Creatine Primarily via de Novo Synthesis Rather Than from Dam Milk ,

During lactation, there may be a higher need for creatine replacement due to the provision of creatine to the milk. Our objectives were to: 1) quantify the creatine concentration in rat milk; 2) determine the origin of milk creatine; 3) determine the activities of the enzymes of creatine synthesis in lactating rats and pups; and 4) quantify the origin of the creatine that accumulates in rat pups. The origin of milk creatine was determined in 4 dams following the administration of 14C-creatine by measuring the isotopic enrichment of creatine in the milk and plasma. The activities of the 2 enzymes involved in creatine synthesis were compared in lactating and virgin females (n = 7). For all experiments, the litter size was standardized to 8 pups. The data indicated that the mammary gland extracts creatine from the circulation rather than synthesizing it. This was confirmed by our failure to find substantial activities of the enzymes of creatine synthesis in mammary glands. The provision of milk creatine requires an additional 35–55% of creatine above the daily requirement by lactating rat dams. However, there was no increased creatine synthesis by these dams; the additional creatine was largely provided by hyperphagia, because creatine is present in commercial rat diet. There was a substantial accumulation of creatine in the growing pups, but only ∼12% was obtained from milk. The great bulk of creatine accretion was via de novo synthesis by the pups, which imposed a substantial metabolic burden on them.

Dietary palm olein oil augments cardiac antioxidant enzymes and protects against isoproterenol-induced myocardial necrosis in rats

Wistar rats, 150-200 g, of either sex, were fed daily with commercial rat diet supplemented with palm olein oil in two doses (5% v/w (n = 16) and 10% v/w (n = 16) of diet) for 30 days. Control rats (n = 16) were fed with normal diet. On the 29(th) and 30(th) days, 8 rats from each group were administred isoproterenol (85 mg/kg, s.c., 24-h interval). On the 31(st) day, all rats were sacrificed and myocardial tissues were studied for thiobarbituric acid reactive substances (TBARS), antioxidant enzymes and light microscopic changes, along with the ferric-reducing ability of plasma (FRAP). A significant rise in myocardial superoxide dismutase (SOD), catalase and glutathione peroxidase (GPx) activity and FRAP level were observed in rats fed with palm olein oil. Isoproterenol caused an increase in myocardial oxidative stress in control rats, as evidenced by an increase in myocardial TBARS level, reduction in FRAP and myocardial SOD, catalase and GPx activity, along with focal necrosis of cardiac muscle fibres on light microscopy. The rise in myocardial TBARS and depletion of SOD and catalase activity following isoproterenol administration were prevented in palm-olein-oil-supplemented diet-fed rats at both doses. Isoproterenol-induced myocardial light-microscopic changes were also prevented in the treated groups. The results suggest that dietary palm olein oil caused augmentation of myocardial antioxidant enzymes and protected against isoproterenol-induced myocardial necrosis and associated oxidative stress.

Zu Larval-, Adultentwicklung und Organisation einer Zucht der Mittelmeer-Feldgrille ( Gryllus bimaculatus de Geer, 1773)

The working routine and detailed experiences of the systematic breeding of the Mediterranean or two-spotted field cricket ( Gryllus bimaculatus) at the Department of Animal Ecology I, University of Bayreuth, are described. The animals are kept under “optimal conditions” at 27 °C and a long day light cycle (16 h light/8 h dark). Eggs are laid in wet peat or sand. Young crickets hatch after 13 days. Larval development in the subfamily Gryllidae consists of eight or nine larval stages and takes about 45–50 days under the conditions employed in Bayreuth's keeping facility. In nature, the number of larval instars and developmental time can fluctuate substantially, depending on temperature and food quality. Before the adult moult, mass is slightly reduced. Body length, length of the antenna and pronotum width advance gradually from moult to moult. Larvae differ from the adults in being wingless and unable to fly. Larvae and adults are fed on a mixture of commercial cat, rabbit and rat diet. Crickets are an excellent source of proteins for many insectivore species. Examples of protein and glycogen contents of different body compartments are given. The protein content rises between day one and two after adult emergence and glycogen stores are also built up during the first days of adult life. Many physiological changes take place in the adult females: the ovary mass rapidly increases from the third day after adult emergence. The mass of muscles exclusively used for flight activity decreases. These events stand in context of dispersal flights before reproduction. The fat body acts as the main compartment for synthesis and storage of highly energetic substrates (lipid and protein), the flight muscles mainly store protein and glycogen.

Mechanism study of chitosan on lipid metabolism in hyperlipidemic rats.

It has been reported that plasma and liver cholesterol concentrations decrease when animals are fed with chitosan, but the mechanism is unclear. Four wk old male SD (Sprague-Dawley) rats were fed a commercial rat diet (cholesterol-free diet, negative control, NC), cholesterol-enriched diet containing 5% of chitosan (CH) or cholesterol-enriched diet containing 5% of cellulose (CE) and 5% of lard for 12 weeks. We would investigated the effects of chitosan on plasma and liver cholesterol levels, liver weight, bile acids concentrations of fecal and hepatic LDL receptor mRNA expression. The results showed that chitosan could decrease levels of total cholesterol (TC), low density lipoprotein cholesterol (LDL-C) in plasma (p<0.05), and TC, total triglyceride (TG) in liver (p<0.05), and increase fecal bile acids excretion (p<0.05), but the levels of TG and HDL-C in plasma was unchanged (p>0.05). In addition, the result of RT-PCR test showed that saturated fat and cholesterol fed could significantly induce the reduction of LDL receptor mRNA levels, while chitosan could increase hepatic LDL receptor mRNA levels. This study suggested that chitosan improve lipid metabolism by regulating TC and LDL-C by upregulating of hepatic LDL receptor mRNA expression, increasing the excretion of fecal bile acids.

Dahl salt-sensitive rats develop hypovitaminosis D and hyperparathyroidism when fed a standard diet

The Dahl salt-sensitive rat (S), a model for salt-sensitive hypertension, excretes protein-bound 25-hydroxyvitamin D (25-OHD) into urine when fed a low salt diet. Urinary 25-OHD increases during high salt intake. We tested the hypothesis that continuous loss of 25-OHD into urine would result in low plasma 25-OHD concentration in mature S rats raised on a standard diet. Dahl S and salt-resistant (R) male rats were raised to maturity (12-month-old) on a commercial rat diet (1% salt) and switched to 0.3% (low) or 2% (high) salt diets 3 weeks before euthanasia. Urine (24 h) was collected at the end of the dietary treatments. Urinary 25-OHD and urinary 25-OHD binding activity of S rats were three times that of R rats, resulting in lower plasma 25-OHD and 24,25-dihydroxyvitamin D concentrations in S rats than in R rats (P < 0.001). Plasma parathyroid hormone concentrations of S rats were twice that of R rats. S rats fed 2% salt had higher plasma 1,25-dihydroxyvitamin D concentrations than those fed 0.3% salt (P = 0.002). S rats excreted more calcium into urine than R rats (P < 0.001) and did not exhibit the expected calciuric response to salt. Proteinuria of the S rats was three times that of the R rats, suggesting kidney damage in the S rats. Low plasma 25-OHD and 24,25-dihydroxyvitamin D and high plasma 1,25-dihydroxyvitamin D and PTH concentrations seen in the mature S rats have also been reported for elderly patients with low-renin (salt-induced) hypertension. An implication of this study is that low vitamin D status may occur with age in salt-sensitive individuals, even when salt intake is normal.

Effects of Calcium Lactate and Chungkukjang on Calcium Status in Rat

Effects of dietary calcium lactate (CaL-A) and Chungkukjang (Korean native fermented soybean) on bone mass, calcium status, body weight, serum glucose and cholesterol levels in young male rats were investigated. Chungkukjang was fermented by mixing 4 types of Bacillus sp., and then dried at 45oC. Calcium lactate was prepared from the ash of black snail. The rats were fed a commercial rat diet for 1 week and then the experimental diets for 4 weeks. Animals were divided into four dietary groups: one calcium-deficient diet (Ca-De) and one of three with calcium supplemented diets (5 g calcium/kg diet) with either calcium phosphate (Ca-P), CaL-A, or CaL-A＋Chungkukjang (CaL-AC). Calcium supplemented diets contained 39 g Ca-P/kg diet and 28 g/kg of calcium lactate in the CaL-A and CaL-AC diets. Body weight gains during the 4 weeks in the Ca-P, CaL-A, CaL-AC and Ca-De groups were 130.45 g, 112.50 g, 143.40 g and 10.20 g, respectively. Feed consumption of the groups from high to low was CaL-AC＞Ca-P＞CaL-A＞Ca-De. The Ca-De group had low femur weights and low serum calcium concentrations, while they were comparatively high in CaLAC, Ca-P and CaL-A groups. The Ca-De groups excreted less calcium in urine than did the other rats, probably due to increased absorption of the mineral in Ca-P, CaL-A and CaL-AC groups. Microscopic observations revealed that there were many regularly spaced holes in the femur of Ca-De group, while there were much smaller regularly spaced holes in Ca-P group. However, no holes in femur were observed in the CaL-A and CaL-AC groups. Bone surfaces were especially smooth and clean in the CaL-AC group. Serum concentrations of glucose and total cholesterol were remarkably lower in the CaL-AC group than in the other supplemented groups. These results suggest that calcium from CaL-A has higher bioavailability than from Ca-P, and dietary Chungkukjang may have a beneficial effect on calcium metabolism.

Effect of dietary palm olein oil on oxidative stress associated with ischemic-reperfusion injury in isolated rat heart

BackgroundPalm olein oil (PO), obtained from refining of palm oil is rich in monounsaturated fatty acid and antioxidant vitamins and is widely used as oil in diet in many parts of the world including India. Palm oil has been reported to have beneficial effects in oxidative stress associated with hypertension and arterial thrombosis. Oxidative stress plays a major role in the etiopathology of myocardial ischemic-reperfusion injury (IRI) which is a common sequel of ischemic heart disease. Antioxidants have potent therapeutic effects on both ischemic heart disease and ischemic-reperfusion injury. Information on the effect of PO on ischemic-reperfusion injury is, however, lacking. In the present study, the effect of dietary palm olein oil on oxidative stress associated with IRI was investigated in an isolated rat heart model. Wistar rats (150–200 gm) of either sex were divided into three different groups (n = 16). Rats were fed with palm olein oil supplemented commercial rat diet, in two different doses [5% v / w (PO 5) and 10% v / w (PO 10) of diet] for 30 days. Control rats (C) were fed with normal diet. After 30 days, half the rats from each group were subjected to in vitro myocardial IRI (20 min of global ischemia, followed by 40 min of reperfusion). Hearts from all the groups were then processed for biochemical and histopathological studies. One way ANOVA followed by Bonferroni test was applied to test for significance and values are expressed as mean ± SE (p < 0.05).ResultsThere was a significant increase in myocardial catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (GPx) activities with no significant change in myocardial thiobarbituric acid reactive substances (TBARS) only in group PO 5 as compared to group C. There was no light microscopic evidence of tissue injury. A significant rise in myocardial TBARS and depletion of myocardial endogenous antioxidants (SOD, CAT and GPx) along with significant myocyte injury was observed in control rats subjected to ischemia-reperfusion (C IR). Hearts from palm olein oil fed rats subjected to ischemia-reperfusion (PO 5 IR and PO 10 IR) were protected from increase in TBARS and depletion of endogenous antioxidants as compared to C IR group. No significant myocyte injury was present in the treated groups.ConclusionsThe present study demonstrated for the first time that dietary palm olein oil protected rat heart from oxidative stress associated with ischemic-reperfusion injury.

Isolated canine and murine intestinal cells exhibit a different pattern of fuel utilization for oxidative metabolism.

The amount and type of dietary fiber influences the end-products of fermentation and thus fuel availability to intestinal tissue. Metabolic fuel usage was studied in intestinal cells isolated from dogs consuming a commercial diet or from rats consuming either a commercial rat diet or dog diet to examine preferential fuel usage, the effect of diet, and species differences. Production of 14CO2 was measured by incubating cells in media containing either D-[U-14C]glucose, [1-14C]n-butyrate, L-[U-14C]glutamine, or [1-14C]propionate with or without competing substrates. The presence of a mixture of 5 mM each of glucose, butyrate, propionate, and acetate and 1 mM glutamine in the media decreased CO2 production from glucose, glutamine, and propionate by canine enterocytes (P < 0.05) and from glutamine and propionate by canine colonocytes (P < 0.05). The presence of glutamine in the media decreased glucose oxidation by murine enterocytes, regardless of the diet. Similarly, glutamine decreased glucose oxidation by murine colonocytes (P < 0.05), but only when the rats had consumed the rat diet. Regardless of diet, murine colonocytes oxidized more butyrate (P < 0.01) than did enterocytes, and murine enterocytes tended (P < 0.07) to oxidize more glucose than did colonocytes. The proportion of propionate in colonic contents was higher in dogs than in rats (P < 0.02), and the proportion of butyrate tended to be higher in contents from rats than in those from dogs (P < 0.08). Colonic and cecal wet weights were decreased (P < 0.05) when rats were fed the commercial dog diet. Preferred utilization of substrates by isolated canine enterocytes and colonocytes differed from that of murine intestinal cells. These differences were only partially overcome by feeding the same diet to each species.

Tea consumption does not affect iron absorption in rats unless tea and iron are consumed together

Phenolic compounds may influence iron absorption by complexing iron in the intestinal lumen or by altering intestinal permeability. We assessed the effects of tea on iron absorption and intestinal permeability in rats in two experiments. In experiment 1, rats maintained on a commercial rat diet were fasted overnight with free access to water and then gavaged with 1.0 ml of 59Fe labeled FeCl 3 (0.1 mM or 1.0 mM) and lactulose (0.5 M) in water or black tea. Iron absorption was estimated from 59Fe retention. Intestinal permeability was evaluated by lactulose excretion in the urine. Iron absorption was lower when given with tea at both iron concentrations but tea did not affect lactulose excretion. In experiment 2, rats maintained on a commercial rat diet were divided into two groups. One group was given black tea as the only source of water for 3 d. The other group was given water. Both groups were fasted overnight with free access to water and then gavaged with 1.0 ml of water or black tea containing 59Fe labeled FeCl 3 (0.1 mM) and lactulose (0.5 M). Iron absorption was not affected by 3 d of tea consumption but was decreased when delivered in tea. Lactulose excretion was not affected by 3 d tea consumption or by delivery in tea. These data suggest that tea affects iron absorption by forming iron complexes in the lumen.

A data-derived safety (uncertainty) factor for the intense sweetener, saccharin.

An increased incidence of bladder cancer is found when male rats are fed high dietary concentrations of sodium saccharin (3% or more) from birth. This toxicity has been used as the basis for the development of a data-derived safety factor. Such an effect would attract an extra factor (10-fold) for nature of toxicity and in the absence of other data would result in a high overall safety factor. However the extensive mechanistic database on sodium saccharin allows an assessment of the potential relevance of the effect for humans. In addition the effect is only seen under specific conditions in rats, i.e. largely with the sodium salt and with a commercial rat diet. The effect is not related to the concentration of saccharin in the rat urine or bladder so that toxicokinetic considerations are simplified. The extensive animal database allows the determination of data-derived factors for inter-species differences in both toxicokinetics and toxicodynamics. Based on this analysis an overall safety factor of 50 (which includes the factor of 10 for severity of effect) would appear appropriate at the present time. This factor, and the ADI which would result from its application, are consistent with the absence of an association between the consumption of artificial sweeteners and bladder cancer in humans.

Possible use of alfalfa (Medicago sativa) as supplement in infant nutrition: Comparison of weight gained by rats fed on alfalfa and a popular weaning diet

AbstractRats (Wistar strain, 3 weeks old, 12 rats per group) were fed either Alfamix (alfalfa nutrient cake and roasted corn 1:4 w) or Weanimix (roasted groundnut:roasted corn, 1:4 w) or stock diet (commercial rat diet) for 4 weeks to compare the ability of Alfamix and Weanimix to support the growth and general well‐being of the rats. Results indicated that rats fed on Alfamix consumed significantly more feed (11.95 g day−1) than those fed on Weanimix (9.47 g day−1). Furthermore the protein efficiency ratio of the Alfamix group (1.41) was significantly higher than that for the Weanimix group (0.96); consequently, the weight gained by the Alfamix group was higher than that by the Weanimix group. There were no significant differences in the haematological indices of the two groups. These results suggest that alfalfa nutrient cake incorporated into weaning diets of children could enhance their nutritional status.

Differential feeding responses evoked in the rat by NPY and NPY 1–27 injected intracerebroventricularly

Neuropeptide Y (NPY) given by the intracerebroventricular (ICV) route in the rat evokes hyperphagic-like feeding. To examine the molecular nature of action of NPY, comparisons were made between the central effects of this peptide and a newly synthesized amino-terminus fragment, NPY 1–27. A single guide tube was implanted stereotaxically to rest just above a lateral cerebral ventricle so that ICV injections in a volume of 10 μl of either CSF control vehicle or peptide could be given in the unrestrained rat. Native NPY or NPY 1–27 was given in doses of 5.0 or 10.0 μg, whereas nondeprotected NPY was infused in a dose of 10.0 μg. The intakes of either regular commercial rat diet or specially prepared chocolate-flavored biscuits as well as water were recorded intermittently for 4.0 h following each ICV infusion. Although a clear-cut dose response with a latency of similar magnitude emerged for both molecules, NPY was found to be nearly twice as potent as NPY 1–27 in inducing spontaneous feeding. A corresponding infusion in the same volume of either nondeprotected NPY or CSF control vehicle was without effect. When chocolate-flavored biscuits were provided to the rat, an ICV infusion of a 10.0 μg dose of NPY enhanced significantly both rate of eating and total cumulative intake of flavored food in comparison to that after a similar infusion of NPY 1–27 or either control solution. These results suggests that native NPY acting centrally affects gustatory and/or olfactory systems to a much greater degree than does NPY 1–27. Consequently, the carboxy terminus amino acids 28–36 appear to be essential in shifting the sensory threshold for food ingested by the rat and thus may govern the overall magnitude of its intake.

Ovariectomy, dietary zinc, and bone metabolism in retired breeder rats

Bone mineral turnover was studied in sham and ovariectomized (ovax) retired breeder rats after 16 wk of dietary treatment. Rats were fed either a commercial rat diet (CRD) containing high calcium and cholecalciferol or egg-white diets (EWD) containing 2 g Ca/kg, 1,25-(OH)2cholecalciferol (5 micrograms/kg), and either 10 or 200 mg zinc/kg. In rats fed EWD, high Zn enhanced femoral Zn deposition and concentration but did not affect serum Ca levels, bone mineral content (BMC), or turnover. Serum Ca levels and BMC were greater in sham rats and there was a gain in femoral Ca and phosphorus compared with the loss of these minerals in ovax rats. In CRD-fed ovax rats, values for these variables were similar to those of CRD-fed shams and there was no bone mineral loss. These data suggest that ovarian function may be a prerequisite for the beneficial effects of diets containing 1,25-(OH)2cholecalciferol and low Ca on bone metabolism.