Rodent Feeding Research Articles

Effect of an Enteral Formula Enriched with ω-3 Fatty Acids, Carnitine, and Vitamin D on Body Weight, Heart Weight, and Blood Biochemical Parameters in a Dahl Rat Heart Failure Model.

Malnutrition is known to worsen the prognosis of chronic heart failure. To gain information that may be helpful in establishing appropriate nutritional interventions for chronic heart failure, the present study was performed to investigate the efficacy of nutritional management with two enteral formulas, EH, with a standard nutritional composition, and ER, fortified with omega-3 fatty acids, vitamin D, and carnitine. Experiments were performed in a Dahl rat heart failure model. After being fed a standard rodent feed (MF) containing 8% NaCl (high salt-MF [HS-MF]) from 6 to 11 weeks of age, rats were assigned to freeze-dried EH or ER diets with an NaCl concentration of 8% (HS-ER or HS-EH) until 18 weeks of age. Serum albumin was significantly higher at 14 and 17 weeks of age in rats fed the HS-ER and HS-EH diets compared with those remaining on the HS-MF diet. Body weight was also significantly higher at 14 and 17 weeks of age in animals fed the HS-ER diet, showing that nutritional deterioration was prevented. Additionally, heart weight was significantly lower at 18 weeks of age in the HS-ER group than that in the HS-MF group, suggesting that cardiac hypertrophy was prevented. This study demonstrated improved nutritional status in a heart failure model in Dahl rats presumably owing to differences in nutritional composition in the diets. Future studies are needed to explore optimal nutritional management with enteral formulas in patients with chronic heart failure.

Regulation of Energy and Glucose Homeostasis by the Nucleus of the Solitary Tract and the Area Postrema.

The central nervous system regulates feeding, weight and glucose homeostasis in rodents and humans, but the site-specific mechanisms remain unclear. The dorsal vagal complex in the brainstem that contains the nucleus of the solitary tract (NTS) and area postrema (AP) emerges as a regulatory center that impacts energy and glucose balance by monitoring hormonal and nutrient changes. However, the specific mechanistic metabolic roles of the NTS and AP remain elusive. This mini-review highlights methods to study their distinct roles and recent findings on their metabolic differences and similarities of growth differentiation factor 15 (GDF15) action and glucose sensing in the NTS and AP. In summary, future research aims to characterize hormonal and glucose sensing mechanisms in the AP and/or NTS carries potential to unveil novel targets that lower weight and glucose levels in obesity and diabetes.

Rodent and broiler feeding studies with maize containing genetically modified event DP-915635-4 show no adverse effects on health or performance

Several regulatory agencies continue to require animal feeding studies to approve new genetically modified crops despite such studies providing little value in the safety assessment. Feeding studies with maize grain containing event DP-915635-4 (DP915635), a new corn rootworm management trait, were conducted to fulfill that requirement. Diets fed to Crl:CD®(SD) rats for 90 days contained up to 50% ground maize grain from DP915635, non-transgenic control, or non-transgenic reference hybrids (P1197, 6158, and 6365). Ross 708 broilers received phase diets containing up to 67% maize grain from each source for 42 days. Growth performance was compared between animals fed DP915635 and control diets; rats were further evaluated for clinical and neurobehavioral measures, ophthalmology, clinical pathology, organ weights, and gross and microscopic pathology, whereas carcass parts and select organ yields were determined for broilers. Reference group inclusion assisted in determining natural variation influence on observed significant differences between DP915635 and control groups. DP915635 maize grain diet consumption did not affect any measure evaluated in either feeding study. Results demonstrated DP-915635-4 maize grain safety and nutritional equivalency when fed in nutritionally adequate diets, adding to the existing literature confirming the lack of significant effects of feeding grain from genetically modified plants.

Stimulation of Naïve Adipose-Derived Stem Cells with Mesenteric Lymph from Chronic Alcohol-Fed Rats Induces IL-33 Release Associated with Cellular Necrosis

Our studies show that chronic alcohol feeding in rodents induced mesenteric lymphatic leakage into surrounding perilymphatic adipose tissue (PLAT) that was associated with increased fat regulatory T cells (fTregs), that were not increased in the circulation, suggesting local expansion of fTregs in PLAT. Increased visceral fTregs are implicated in age-associated insulin resistance. The IL-33 receptor, ST2, has been implicated in fTreg cell development and is critical for their accumulation in PLAT. IL-33 is released upon cell death by visceral adipose tissue stromal or adipose derived stem cells (ADSCs) and acts as an alarmin to signal tissue damage. Whether lymphatic leakage in alcohol-fed animals results in death of ADSCs, release of IL-33, and activation of the IL-33/ST2 signaling pathway leading to PLAT fTreg accumulation has yet to be explored. Here, we tested the hypothesis that stimulation of naïve ADSCs with lymph from chronic alcohol-fed animals would lead to increased IL-33 via cell death. Male Fischer 344 rats were randomized to a Lieber-DeCarli liquid diet containing 36% of calories from alcohol or pair-fed an isocaloric diet for 10 weeks (N=10/group). Mesenteric lymph was collected from anesthetized alcohol- and pair-fed animals via the lymph fistula technique. PLAT ADSCs, isolated from age-matched, naïve, chow-fed rats were cultured until adherent and stimulated with 5% v/v lymph from alcohol- or pair-fed animals for 24 hrs. Supernatant was collected, and IL-33 concentration was measured by commercially available ELISA. Adherent ADSCs were stained with 7-AAD and CytoCalcein fluorescent dyes to assess cell viability using fluorescence microscopy. Viable and necrotic cells were counted using QuPath software. Statistical differences were assessed using one-way ANOVA in GraphPad Prism. Results show a 2.5-fold increase in the concentration of IL-33 in supernatant of ADSCs stimulated with lymph from alcohol-fed animals compared to ADSCs stimulated with lymph from pair-fed animals. In addition, ADSC necrosis was 4-fold greater in wells stimulated with lymph from alcohol-fed animals than in those stimulated with control lymph or vehicle. In contrast, lymph stimulation of ADSCs from control-fed animals did not show a significant increase in IL-33 release as compared to vehicle treated controls. These data indicate presence of mediators that induce IL-33 release in lymph from alcohol-fed animals and support the hypothesized involvement of the IL-33/ST2 pathway in chronic alcohol associated ADSC cell death. Supported by K01AA026640 (FSS), 1F30AA030909-01 (KW), 5T32AA007577-23 (PM). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Feeding and Reproductive Ecology of Rodents: A Review

Feeding and Reproductive Ecology of Rodents: A Review

Dry Heat Sterilization of a Pelleted, Natural Ingredient Rodent Diet.

Sterilization of rodent feed is recommended to eliminate potential murine pathogens and minimize microbial variability between batches. Most research institutions sterilize feed using steam/pressure (autoclave) or irradiation. Both methods have advantages and disadvantages that contribute to their suitability, including cost, maintenance, availability, and alterations to the exposed product. Dry heat sterilization, which has been in use for over 75 y, uses higher temperatures and longer sterilization times than steam autoclave and is most often used for delicate instruments or products that would be damaged by water such as powders or oil-based liquids. Dry heat sterilization in vivaria has been limited to date but is gaining popularity due to lower initial purchase and ongoing operational costs as compared with steam autoclaves. Little published information exists on the effects of dry heat sterilization on animal feed. We evaluated the sterility and chemical alterations of a natural ingredient, pelleted, rodent diet (NIH-31) after exposure to dry heat. Feed sterility was achieved using a dry heat exposure temperature of 160 °C (320 °F) for 4 h. This exposure resulted in a significant loss of heat-labile vitamins and significantly more acrylamide production as compared with the nonsterile, irradiated, and autoclaved feed.

Evaluation of Rodent Diet Stability when Stored in Conditions that Diverge from Guide Parameters.

An essential aspect of animal resource programs is the storage and provision of food for a variety of species. Environmental parameters for feed storage conditions (temperature less than 70 °F; relative humidity less than 50%) are recommended in the Guide for the Care and Use of Laboratory Animals, along with aspects of nutrition such as palatability, vermin-control measures, diet quality, and integrity of feed bags. After receiving a suggestion for improvement for environmental conditions in 2 feed storage locations during an AAALAC accreditation visit, we hypothesized that the packaging of contemporary rodent feed could sustain wider environmental variations in temperature and humidity without adverse impact on integrity and palatability. This study evaluated representative feed storage sites across campus buildings to capture the variation in environmental conditions that are inherent to large and diverse animal care programs. Each test storage location held 2 identical bags of feed (same type, lot, and expiration date) that were stored from June to September of 2021; some aspects of the project were repeated during summer 2022 with a similar rodent feed. Baseline nutrients were analyzed from feed samples collected at time 0 (control) and again after 1 and 3mo of storage. The overall nutritional values measured in feed at the end of the study were not significantly different from control values, regardless of test site and variation in environmental parameters. Retinol (as a measure of Vitamin A) was the only component that decreased significantly; however, final retinol levels were consistently above those necessary for appropriate nutrition for mice. Our animal care program stakeholders were briefed on the outcomes of this study with the intent to verify at future AAALAC site visits that our storage conditions are adequate for maintaining the nutritional quality of packaged rodent feed.

Time-Restricted Feeding and Weight Loss in Obesity: A Mini Review on the Impacts on Skeletal Muscle Mass

Across the globe, obesity is a significant concern for public health, a disease characterized by excessive accumulation of body fat, with a negative impact on health. Time-restricted feeding (TRF), in which food accessibility is restricted to a variable period of 8–10 h, especially in the active phase, inducing a prolonged fasting period, is a strategy with potential effects in preventing obesity. Evidence in preclinical studies demonstrated that TRF attenuates the impacts of metabolic disturbances related to high-fat diet feeding in rodents. Through these discoveries, there has been growing interest in revealing the effects associated with TRF in preventing obesity and its comorbidities, as well as investigating its effects in humans. Although TRF is a promising alternative to reduce the impact of obesity, it is necessary to investigate the results on skeletal muscle tissue. Muscle tissue is important for body energy expenditure; however, caloric restriction can negatively impact protein turnover and induce loss of muscle mass, influencing the basal metabolic rate and weight loss. This mini review examined the scientific literature exploring the effects of time-restricted feeding (TRF) on muscle mass. Although still incipient, the findings related to TRF applied to obese individuals highlight the importance of carrying out dietary control, as well as the consumption and fractionation of proteins, to maintain a balanced protein turnover and, consequently, muscle mass.

A 90-day rodent feeding study with grain for genetically modified maize L4 conferring insect resistance and glyphosate tolerance.

A 90-day rat feeding study was performed to conduct a safety assessment on L4, a multi-gene genetically modified maize, conferring "Bt" insect resistance and glyphosate tolerance. A total of 140 Wistar rats were assigned to seven groups, 10 animals/group/sex, which comprised three genetically modified groups fed diets containing different concentrations of L4, three corresponding non-genetically modified groups fed diets containing different concentrations of zheng58 (parent plants), and a basal diet group fed the standard basal diet for 13 weeks. The fed diets contained L4 and Zheng58 at w/w% percentages of 12.5%, 25.0%, and 50% of the total. Animals were evaluated on some research parameters, including general behaviour, body weight/gain, feed consumption/efficiency, ophthalmology, clinical pathology, organ weights, and histopathology. Throughout the feeding trial, all animals were in good condition. No mortality and no biologically relevant effects or toxicologically significant alterations were observed in the total research parameters of the rats in the genetically modified groups compared with those in the basal diet group or their corresponding non-genetically modified groups. No adverse effects were observed in any of the animals. The results indicated that L4 is as safe and wholesome as conventional, non-genetically modified control maize.

Increases in plasma n-3 tetracosapentaenoic acid and tetracosahexaenoic acid following 12 weeks of EPA, but not DHA, supplementation in women and men

Dietary feeding and stable isotope studies in rodents support that the 24-carbon omega-3 polyunsaturated fatty acids, tetracosapentaenoic acid (24:5n-3, TPAn-3) and tetracosahexaenoic acid (24:6n-3, THA), are immediate precursors to docosahexaenoic acid (DHA, 22:6n-3). In this study, we assessed for the first time, changes in TPAn-3 or THA levels following omega-3 PUFA supplementation in humans, providing insight into human omega-3 PUFA metabolism. In this secondary analysis of a double-blind randomized control trial, women and men (19 – 30 years, n = 10 – 14 per sex, per diet) were supplemented with 3 g/day EPA, DHA, or olive oil control for 12 weeks. Plasma TPAn-3 and THA concentrations were determined by gas chromatography-mass spectrometry to determine changes following supplementation in a sex-specific manner (sex x time). EPA supplementation significantly increased (p < 0.0001) plasma TPAn-3 by 215% (1.3 ± 0.1 – 4.1 ± 0.7, nmol/mL ± SEM) and THA by 112% (1.7 ± 0.2 – 3.6 ± 0.5, nmol/mL ± SEM). Furthermore, women had 111% and 99% higher plasma TPAn-3 and THA in the EPA supplemented group compared to men (p < 0.0001). There were no significant effects of time on plasma TPAn-3 or THA concentrations in the DHA supplemented or olive oil supplemented groups. In conclusion, EPA, but not DHA, supplementation in humans increased plasma TPAn-3 and THA levels, suggesting that THA accumulates prior to conversion to DHA in the n-3 PUFA synthesis pathway. Furthermore, women generally exhibit higher plasma TPAn-3 and THA concentrations compared with men, suggesting that women have a greater ability to accumulate 24-carbon n-3 PUFA in plasma via EPA and DPAn-3 elongation, which may explain the known higher DHA levels in women.Summary: In this secondary analysis of a double-blind randomized control trial, we assessed changes in omega-3 (n-3) tetracosapentaenoic acid (24:5n-3, TPAn-3) and tetracosahexaenoic acid (24:6n-3, THA) plasma levels in women and men (19 – 30 years, n = 10 – 14 per sex, per diet) following 12-weeks of n-3 PUFA supplementation (3 g/day EPA, DHA or olive oil). Women had higher plasma TPAn-3 in all supplementation groups and higher THA levels in the EPA and olive oil groups (p < 0.0001) compared to men. EPA supplementation increased (p < 0.0001) plasma TPAn-3 by 215% (1.3 ± 0.1 – 4.1 ± 0.7, nmol/mL ± SEM) and THA by 112% (1.7 ± 0.2 – 3.6 ± 0.5, nmol/mL ± SEM), but DHA supplementation had no effect. For the first time in humans, we show that plasma TPAn-3 and THA levels are higher in women and increased with EPA, but not DHA supplementation, suggesting an accumulation of THA prior to conversion to DHA in the n-3 PUFA synthesis pathway.

Increased availability of preferred food and decreased foraging costs from degraded grasslands lead to rodent pests in the Qinghai-Tibet Plateau

The increased population density of rodent species during ongoing grassland degradation further deteriorates its conditions. Understanding the effects of grassland degradation on rodent feeding habits is of great value for optimizing grassland management strategies. In this study, lightly degraded (LD), moderately degraded (MD), severely degraded (SD), and reseeded grassland (RG) were selected and their plant resources and soil physical properties were investigated. In addition, the study usedITS2barcode combined with the Illumina MiSeq sequencing method to analyze the food composition and proportion of plateau zokors in different grassland conditions. The results showed that, with grassland degradation, plant biomass decreased, but the relative proportion of forbs increased (LD: 32.05 ± 3.89%; MD: 28.97 ± 2.78%; SD: 49.16 ± 4.67% and RG: 10.93 ± 1.53%). Forbs were the main food of the plateau zokor, accounting for more than 90% of their diet, and the animal had a clear preference forPotentillaspecies; the soil compaction of feeding habits showed a decreasing trend in the 10–25 cm soil layer, suggesting a decreased foraging cost. Nutritional analysis showed that the stomach content of crude protein in zokors feeding on MD grassland was significantly higher than that of animals feeding on the other grassland types. Structural equation modeling showed that soil physical properties and the relative biomass of forbs had significant (P&amp;lt; 0.05) and extremely significant (P&amp;lt; 0.001) impacts on the population density of plateau zokors, with direct impact contribution rates of 0.20 and 0.63. As the severity of grassland degradation increased, although the aboveground and underground biomass of the plants decreased, the proportion of food preferred by the plateau zokor increased, and the corresponding changes in the feeding environment resulted in decreased foraging energy expenditure, thereby increasing the suitability of the degraded grassland for the plateau zokor. Compared with degraded grassland, the food diversity and evenness of zokors increased, the food niche width enlarged, and the proportion of weeds decreased in RG, which increased the difficulty of obtaining food. Reseeding in grassland management is therefore an effective way to control plateau zokors.

The limitations of investigating appetite through circuit manipulations: are we biting off more than we can chew?

Disordered eating can underpin a number of debilitating and prevalent chronic diseases, such as obesity. Broader advances in psychopharmacology and biology havemotivated some neuroscientists to address diet-induced obesity through reductionist, pre-clinical eating investigations on the rodent brain. Specifically, chemogenetic and optogenetic methods developed in the 21st century allow neuroscientists to perform in vivo, region-specific/projection-specific/promoter-specific circuit manipulations and immediately assess the impact of these manipulations on rodent feeding. These studies are able to rigorously conclude whether a specific neuronal population regulates feeding behaviour in the hope of eventually developing a mechanistic neuroanatomical map of appetite regulation. However, an artificially stimulated/inhibited rodent neuronal population that changes feeding behaviour does not necessarily represent a pharmacological target for treating eating disorders in humans. Chemogenetic/optogenetic findings must therefore be triangulated with the array of theories that contribute to our understanding of appetite. The objective of this review is to provide a wide-ranging discussion of the limitations of chemogenetic/optogenetic circuit manipulation experiments in rodents that are used to investigate appetite. Stepping into and outside of medical science epistemologies, this paper draws on philosophy of science, nutrition, addiction biology and neurophilosophy to prompt more integrative, transdisciplinary interpretations of chemogenetic/optogenetic appetite data. Through discussing the various technical and epistemological limitations of these data, we provide both an overview ofchemogenetics and optogenetics accessible to non-neuroscientist obesity researchers, as well as a resource for neuroscientists to expand the number of lenses through which they interpret their circuit manipulation findings.

Cooling-activated dorsomedial hypothalamic BDNF neurons control cold defense in mice.

BDNF and its expressing neurons in the brain critically control feeding and energy expenditure (EE) in both rodents and humans. However, whether BDNF neurons would function in thermoregulation during temperature challenges is unclear. Here, we show that BDNF neurons in the dorsomedial hypothalamus (DMHBDNF ) of mice are activated by afferent cooling signals. These cooling-activated BDNF neurons are mainly GABAergic. Activation of DMHBDNF neurons or the GABAergic subpopulations is sufficient to increase body temperature, EE, and physical activity. Conversely, blocking DMHBDNF neurons substantially impairs cold defense and reduces energy expenditure, physical activity, and UCP1 expression in BAT, which eventually results in bodyweight gain and glucose/insulin intolerance. Therefore, we identify a subset of DMHBDNF neurons as a novel type of cooling-activated neurons to promote cold defense. Thus, we reveal a critical role of BDNF circuitry in thermoregulation, which deepens our understanding of BDNF in controlling energy homeostasis and obesity.

Analysis of localisation of megakaryocytes in the bone marrow of the rat - possible relationship with innervations

Within the bone marrow, megakaryocytes thrive in an environment rich in numerous growth factors that influences their development, maturation, and may play a role in signaling the start of platelet production. Up to now, experiments concerning localisation of various populations of cells in rat bone marrow showed their certain relationship to the blood vessels. There are strikingly few reliable sources of information available in the literature that confirm the relationship between the localisation of these cells in connection to nerve fibers. Therefore the purpose of the present study was to examine if megakaryocytes are located in a defined relation to sensory and sympathetic nerve fibers.&#x0D; The study used immature 6 weeks rats of the Wistar breed of both sexes. The animals were kept under constant lighting conditions (12 hours light-dark cycle) and temperature, and had unrestricted access to water and food (standard laboratory rodent feed).Double immunostaining method was applied with usage of secondary antibodies conjugated with fluorochromes (Cy3 and DTAF) to identify cells. The antibody against CD42d was used to immunolocalise megakaryocytes, while in order to identify the distribution of nerves, antibodies anti-NPY (for detection sympathetic nerve fibers) and anti-PGP 9.5 (sensory nerve fibers) were applied.&#x0D; These findings showed the presence of megakaryocyte and megakaryoblastic cells which were distributed with a close relationship to the blood vessels but some of them were located in parenchyma. It was shown that NPY-positive and PGP 9.5-positive cells were present in the vicinity of blood cells. Furthermore, some megakaryocytes were located near PGP 9.5-labelled cells. The relationship between sympathetic nerve fibers containing neuropeptide Y and megakaryocytes was also detected.

Craniofacial Bone Mineral Density at Muscle Attachment Sites in Mice with Osteogenesis Imperfecta

Osteogenesis imperfecta (OI) is a genetic disease commonly caused by mutations in the COL1A1 or COL1A2 gene affecting the production of type I collagen, a major component of bone that determines the toughness of bone, or its resistance to fracture. Thus, patients with OI present with brittle bones and higher rates of skeletal fractures. Additionally, defects in the collagen framework of developing bones impair their biomineralization, further compromising bone mechanical properties. Previous work in our lab investigated BMD at cranial locations which experience compressive forces during feeding (e.g. joints). Muscles also contribute to cranial growth through tensile forces exerted on bone during contraction, but the relationship between muscle function and bone quality in OI is unclear. The aim of this study is to quantify the BMD in a mouse model of OI, with a focus on skeletal sites associated with cranial musculature. We hypothesize that the mice with OI will have lower BMD in skeletal areas associated with muscle attachment compared to their unaffected littermates.To test our hypothesis, we used the homozygous recessive OI murine (OIM) mouse (B6C3Fe a/a‐Col1a2oim/J), a model for the severe type III OI seen in humans. Adult (16 weeks old) OIM mice (n=11) and wildtype (WT, n=13) littermates were CT scanned, and BMD was measured using the Bruker CTAnalyzer software in 7 regions of interest encompassing muscle attachment sites on the mandible, zygomatic arch, and parietal bone. For each region, BMD values were compared between genotypes by a Kruskal‐Wallis test.OI mice had significantly lower BMD at the coronoid process (p=0.007), parietal bone (p=0.031), and posterior mylohyoid line (p=0.007) compared to WT mice. No significant differences were found in BMD at the gonial angle or zygomatic arch. This suggests a disproportionate weakness of the temporalis and mylohyoid muscles in mice with OI, but not in the masseter muscle. While type I collagen defects impact the structural organization of skeletal muscle, it is possible that masseter muscle function is preserved in OIM mice because of its key roles in rodent feeding and postural control of the jaw. The imbalance between temporalis and masseter muscles may contribute to the prevalence of dental malocclusions in human patients with type III OI.The findings of this study support further exploration of specific muscle groups (e.g. jaw adductors/temporalis, hyoid muscles/mylohyoid) and efforts to improve their functions during feeding, as a way of recovering facial growth and preventing dental malocclusions in OI. A better appreciation of muscle‐bone interactions in the skull and their effect on bone quality can potentially be used to inform oro‐motor therapies to improve feeding function, muscle strength, and facial bone quality for patients with OI.

Once-daily feeding is associated with better health in companion dogs: results from the Dog Aging Project.

A variety of diets have been studied for possible anti-aging effects. In particular, studies of intermittent fasting and time-restricted feeding in laboratory rodents have found evidence of beneficial health outcomes. Companion dogs represent a unique opportunity to study diet in a large mammal that shares human environments. The Dog Aging Project has been collecting data on thousands of companion dogs of all different ages, sizes, and breeds since 2019. We leveraged this diverse cross-sectional dataset to investigate associations between feeding frequency and cognitive function (n = 10,474) as well as nine broad categories of health conditions (n = 24,238). Controlling for sex, age, breed, and other potential confounders, we found that dogs fed once daily rather than more frequently had lower mean scores on a cognitive dysfunction scale, and lower odds of having gastrointestinal, dental, orthopedic, kidney/urinary, and liver/pancreas disorders. Therefore, we find that once-daily feeding is associated with better health in multiple domains. Future research with longitudinal data can provide stronger evidence for a possible causal effect of feeding frequency on health in companion dogs.

Population density, feeding and, reproductive ecology of rodents from Alemsaga Priority State Forest and adjacent farmlands

A study on population density, feeding, and reproductive ecology of rodents from Alemsaga Priority State Forest and the adjacent farmlands was conducted from July 2018-September 2020. Live and snap traps were used for capturing rodents from the study area. The Capture-Mark-Release method was employed to estimate the population size and respective density of rodents. Snap traps were used to capture rodents for body measurement and stomach content analysis. Embryo count was carried out from 64 pregnant females. Data were computed using descriptive statistics and compared with chi-square. Lophuromys simensis, Arvicanthis abyssinicus, Desmomys harringtoni, Mastomys natalensis, Stenocephalemys albipes, Rattus rattus, Arvicanthis dembeensis, Mus musculus, and Acomys cahrinus were recorded from the six habitats. The result indicated that a total of 1140 and 171 individuals were trapped in the study area with live and snap traps, respectively. The average population density of rodents was 47.4 h-1. The highest density was recorded in bushland habitat (75.1 h-l) while the least was in Carissa land (32.2h-l). In terms of species, L. simensis showed the highest density (111.65 h-l) whereas A. cahrinus was the lowest (1.7 ha-1). The overall densities of rodents were 224.82 ha-1 and 162.93 ha-1 during the wet and dry seasons, respectively. The total rodent biomass in the study area was 160,495 g. The number of embryos counted ranged from 4-12 and 2-8 during the wet and dry seasons, respectively. However, there was no statistical significance between the two seasons (χ2 = 0.74, df=1, p&gt; 0.05). Plant matters constituted a higher proportion of stomach contents (64.4%) compared to animal matters (13.2%). Generally, Alemsaga State Forest harbors rodent species with high density and biomass. Proper conservation of the area will contribute to the betterment of species density and biomass.

Rodent scavenging of pig remains potentially increases oviposition sites for primary colonizers.

The feeding of vertebrate scavengers on animal remains has been noted for at least 30years in relation to the creation of postmortem artifacts. However, the subsequent impact on other necrophagous arthropods, which interact with these remains has not been well documented. Herein, we report a rodent (Rattus spp.) feeding event that altered a perimortem wound beneath the jaw of a decomposing swine carcass. Point trauma such as this has been cited as insufficient for insect colonization; however, the resulting enlargement of the wound due to scavenger feeding has the potential to serve as an oviposition site where colonization would typically not be expected otherwise (i.e., in the absence of a wound or the presence of a small wound such as point trauma). In fact, colonization was observed surrounding the site of scavenger alteration. If scavenger artifacts (e.g., postmortem alteration of remains by feeding) are not identified appropriately and recognized for the effects they may have on necrophagous arthropods then associated assessments in forensic investigations could be affected.

Pleiotropic Beneficial Effects of Dietary L-Ascorbic Acid Fortification in Middle-Aged Mice

Background: An enhanced knowledge of the multiple effects of ascorbic acid (AA) in health can broaden our understanding of the impacts of its deficiency. Method: Mice (10-12 month old) were either fed standard rodent feed or AA-fortified diet at 100, 200 and 300 mg/kg of feed, respectively for 8 weeks. On completion of the study, animals were sacrificed, following which haematological, inflammatory/apoptotic marker, oxidative stress markers, and markers of hepatic/renal integrity were assessed. Results: Across the groups, AA fortified diet was associated with an increase in food consumption; however, body weight reduction occurred at the lowest concentration, while weight gain was observed at the higher concentrations. Haematological indices (white cell count, granulocytes, lymphocytes, and red cell count) increased at the highest concentration; while some other red cell parameters decreased. A concentration-dependent improvement in antioxidant status, with the greatest benefit at the highest concentration, was observed. Also, a concentration-dependent modulation of inflammatory markers, lipid peroxidation, lipid profile, and biochemical markers of liver and kidney function was observed. Conclusion: Dietary fortification with AA in middle-aged mice impacted several measurable parameters in a concentration dependent manner. In addition to its antioxidant effects, it was also associated with anti-inflammatory and anti-apoptotic effects.

A 90-Day Subchronic Toxicity Study of Consumption of GH-Transgenic Triploid Carp in Wistar Rats

Genetic modification (GM) offers an alternative strategy to conventional animal breeding. The present study was carried out to investigate the potential health effects of the consumption of growth hormone-transgenic triploid carp (GH-ttc) through a 90-day subchronic rodent feeding study. Wistar rats (n = 10/sex/group) were given formulated diets containing GH-ttc or non-GM carp at an incorporated rate of 2.5%, 5%, or 10% (w/w) for 90 days. An additional control group of rats (n = 10/sex/group) was fed a basic rodent diet. During the 90-day study, clinical observation, ophthalmic examination, body weight, and food intake were evaluated. At the end of the study, rats were killed, and the hematology, serum chemistry, urine test, necropsy, and histopathology were assessed. Compared with the non-GM carp and the basic control groups, no biologically significant differences were observed on clinical signs of toxicity, body weights, food intake, hematology, serum chemistry, urinalysis, organ weight, and histopathology on selected organs for the GH-ttc group. The results of this 90-day subchronic feeding study indicated that, at the dose level used in this study, consumption of GH-ttc showed no subchronic toxicity to Wistar rats.