Pet rat & mouse (companion Rodentia) — diet & nutrition — representative studies (Europe PMC)

Evidence: Pet rat and mouse (Rattus norvegicus) nutrition

Source: Europe PMC (Europe PubMed Central) REST search — first-hand peer-reviewed abstract records, pulled 2026-08-01. Queries covered nutrient requirements, diet formulation, supplementation and deficiency for Rattus norvegicus. The cluster returns 12 representative nutrition studies with abstracts below. Abstract text is verbatim from source; each study is traceable by PMID.

Studies

• PMID 42169097 (2026, Genes and environment : the official journal of the Japanese Environmental Mutagen Society) — A PUFA-rich diet increases endogenous genotoxic stress and mitochondrial DNA damage in mice.. Abstract (opening): <h4>Background</h4>Substitution of dietary saturated fat with seed oils highly enriched in n-6 polyunsaturated fatty acids (PUFAs) has been advocated as healthy strategy to offset elevated cholesterol levels. However, both n-6 as well as n-3 PUFAs, considered essential because vertebrates lack the enzymatic apparatus for their de novo synthesis, are the main source of endogenous DNA damage during the aging process due to their high oxidizability. The membrane pacemaker theory of aging is an extension to the oxidative theory of aging and postulates that higher PUFA content in membrane lipids determines the lifespan of different species.<h4>Objective</h4>We have examined whether a saturated fat-rich diet lacking the essential fatty acids versus a PUFA-rich diet differentially affects lipid profiles and membrane fatty-acid composition, as well as markers of oxidative protein and DNA damage and mitochondrial DNA (mtDNA) integrity in vivo.<h4>Methods</h4>Three-week-old male C57BL/6J mice were fed isocaloric, high-fat diets containing either coconut oil (SFA-rich) or soybean oil (PUFA-rich) for 12 weeks. Plasma and liver lipids were measured, and the fatty acid composition was analyzed in liver and erythrocyte membranes. Endogenous DNA damage was assessed using 1,N⁶-etheno-2'-deoxyadenosine (εdA) detection in blood and liver. mtDNA damage and lipid peroxidation derived protein adducts from liver were also examined.<h4>Results</h4>Mice were maintained on a SFA-rich diet for 12 weeks without exhibiting any symptoms of essential fatty acid deficiency (EFAD) as described in historical literature despite the massive synthesis of compensatory n-9 PUFAs. Furthermore, EFAD mice showed reduced levels of endogenous εdA and mtDNA damage as well as protein adducts originating from the primary n-6 PUFA lipid peroxidation product, 4-hydroxy-2-nonenal. However, some other lipid peroxidation-derived protein adducts, such as malondialdehyde and, surprisingly, 4-hydroxy-2-hexenal, were elevated on a SFA-rich diet.<h4>Conclusions</h4>A PUFA-rich diet, relative to the SFA-rich diet, is associated with increased lipid-peroxidation linked adducts and a greater degree of mtDNA damage in vivo, in parallel with membrane enrichment in n-6 PUFA. These findings provide clear evidence of the biological effects of a PUFA-rich diet on endogenous genotoxic stress. *[CC BY — Open Access, verbatim with attribution.]*

Source: https://pubmed.ncbi.nlm.nih.gov/42169097/

• PMID 42278058 (2026, Animals : an open access journal from MDPI) — Influence of &lt;i&gt;Tenebrio molitor&lt;/i&gt; Meal Inclusion (25-45%) on Clinical and Behavioral Responses in Laboratory Rat Feeding Trial.. Abstract (opening): Although <i>Tenebrio molitor</i> is increasingly explored as a feed ingredient, uncertainty remains regarding the effects of high dietary inclusion levels in model animals. Therefore, this study evaluated physiological and behavioral responses to graded inclusion levels of <i>T. molitor</i> meal (25-45%) in the diets of adult female Wistar rats. The assessed outcomes comprised (i) clinical parameters, (ii) food and water intake, (iii) hematology and serum biochemistry, and (iv) behavior. Across the insect-fed groups, no unintended weight loss or excessive gain was observed; instead, animals modulated their feed intake in a manner consistent with maintaining a relatively stable growth trajectory, without signs of hyperphagia suggestive of nutrient deficiency or anorexia indicative of adverse effects under study conditions. Diet acceptance remained high throughout the experiment, with no feed refusal or behavioral evidence of aversion that might be expected in response to poor palatability or discomfort. Heart rates and respiratory rates remained age-appropriate, showing typical temporal variability. Significant between-group differences were observed in RDW, Retic (%), NEU (%, K/μL), EOS, PLT, and PCT (<i>p</i> < 0.05), while serum analyses revealed significant differences in AST, total bilirubin, creatinine, phosphorus, and BUN (<i>p</i> < 0.05). A moderate negative correlation between individual feed intake and body weight was additionally identified in selected groups. The results of behavioral testing reveal that the dietary inclusion of <i>T. molitor</i> meal at levels up to 45% did not reduce spontaneous activity or elicit anxiety-like responses, and exploratory behavior appeared to be preserved. Overall, the present findings indicate that the gradual incorporation of <i>T. molitor</i> meal at high inclusion levels supported normal growth, physiological function, and behavior in rats under the conditions studied. *[CC BY — Open Access, verbatim with attribution.]*

Source: https://pubmed.ncbi.nlm.nih.gov/42278058/

• PMID 41961055 (2026, Veterinary medicine and science) — Dietary Moringa oleifera Leaves Enhance Biochemical Parameters Resulting in Increase in Egg Production of Layers.. Abstract (opening): <h4>Background</h4>Moringa oleifera leaf meal (MOLM) supplementation is being investigated in the poultry industry for its nutritional and medicinal properties. However, its effects on birds' performance, particularly egg production, are scarce.<h4>Objectives</h4>This study was conducted to investigate the effect of different levels of MOLM on biochemical parameters and egg production of egg-type chickens from day-old to 55 weeks of age.<h4>Methods</h4>A total of 450 day-old chicks were assigned to three dietary treatments of basal diet supplemented with 0%, 1% and 3% MOLM, with 5 replicates of 30 birds each. Data on egg production were collected up to 55 weeks of age. Blood samples were collected from 15 birds per treatment via the jugular vein at 5, 15, 25, 35, 45, and 55 weeks of age for biochemical parameter analysis.<h4>Results</h4>The results showed that feed intake was reduced in birds fed 1% and 3% of M. oleifera. Higher (p < 0.05) egg weights and lower triglyceride were recorded in the birds fed 3% of MOLM during the rearing period. However, plasma calcium, triglyceride level, and egg production were higher (p < 0.05) in birds fed 1% M. oleifera in the diet. Birds in the control group had lower (p < 0.05) average total cholesterol and higher (p < 0.05) feed conversion ratio than those of the other treatments.<h4>Conclusions</h4>To conclude, the incorporation of 1% M. oleifera leaves in layer-type diet for a long period resulted in an increase in blood calcium, triglyceride, and egg production, whereas 3% inclusion significantly increased egg weight but decreased triglyceride level. *[CC BY — Open Access, verbatim with attribution.]*

Source: https://pubmed.ncbi.nlm.nih.gov/41961055/

• PMID 42278008 (2026, Animals : an open access journal from MDPI) — Advantages of Increasing Histidine to Lysine Ratios on Growth Performance, Blood Parameters and Histidine-Containing Dipeptides for Weaning Piglets.. Abstract (opening): A total of 192 weaned piglets (Topigs TN70), 26 days of age, with an initial body weight of 7.2 ± 0.5 kg, were used to determine the standardized ileal digestible (SID) histidine (His) to lysine (Lys) ratio required to maximize growth performance. Six dietary treatments with graded SID His to Lys ratios ranging from 0.2 to 0.38 were generated with the supplementation of L-His to a grain-based basal diet deficient in His. At the end of the trial (day 41 post weaning), 72 male piglets were euthanized for the analysis of histidine-containing dipeptides, particularly carnosine, in the <i>M. longissimus dorsi</i>. In addition, blood samples were collected from 72 piglets to determine plasma urea-nitrogen and hematological parameters. Piglets fed low dietary His (SID His to Lys < 0.27) exhibited hemoglobin concentrations below the reference value, indicating anemia. Muscle carnosine content increased linearly with increasing dietary His and did not reach a plateau within the tested range. Based on growth performance responses, the SID His to Lys ratio required to achieve maximum growth performance in fast-growing piglets is 0.34. These findings emphasize the importance of supervising the SID His to Lys ratio, particularly in practical piglet feed formulations. *[CC BY — Open Access, verbatim with attribution.]*

Source: https://pubmed.ncbi.nlm.nih.gov/42278008/

• PMID 42514390 (2026, Nutrients) — *[Paraphrased derived summary — non-Open-Access source.]* In mice, maternal iron deficiency caused truncal hair loss, smaller size, and abnormal follicles in pups, reversible by postnatal iron repletion. Iron-deficient skin showed reduced Wnt/β-catenin signaling, raised oxidative stress, and activated caspase-3/NF-κB/TGF-β, all reversed by iron; deferoxamine-treated human dermal papilla cells showed the same ROS-mediated Wnt suppression, which N-acetylcysteine blocked. The authors conclude ROS-driven Wnt/β-catenin disruption underlies iron-deficiency hair loss. (Borderline: a mouse mechanistic study on iron and hair growth, loosely relevant to rodent nutrition.)

Source: https://pubmed.ncbi.nlm.nih.gov/42514390/

• PMID 42313570 (2026, Comprehensive reviews in food science and food safety) — Probiotics and Their Functional Role in Mitigating Antinutrient Effects In Vivo-A Systematic Review and Meta-Analysis.. Abstract (opening): Antinutrients like phytic acid and oxalates reduce mineral bioavailability by forming insoluble complexes with iron, zinc, and calcium. Probiotic supplementation may counteract these effects through enzymatic activity (e.g., phytase, oxalate decarboxylase) and microbiota modulation. This PRISMA-based meta-analysis evaluated 27 in vivo studies (chickens, mice, rats) published between 2005 and 2025. Controlled trials assessing probiotic effects on mineral absorption under antinutrient-rich diets were analyzed using random effects models, expressed as standardized mean differences (SMD) with 95% confidence intervals (CI). Probiotic supplementation may enhance selected markers of mineral bioavailability across animal models (broiler, mouse, and rats), although the certainty of evidence was low and between-study heterogeneity was substantial. In broiler chickens, probiotics increased hepatic iron (SMD = 2.05; CI: 0.91-3.20) and liver ferritin levels (SMD = 2.85; CI: 0.90-4.80). In rat models of hyperoxaluria, probiotics reduced renal calcium oxalate deposition (SMD = 0.77; p = 0.0001), though the impact on urinary oxalate levels was not significant (SMD = 0.20). In mouse models, the interventions demonstrated improved gut microbiota diversity without significant alterations in total body weight (SMD = 0.02). Based on low-certainty evidence from heterogeneous animal studies, probiotic supplementation may improve selected mineral-bioavailability outcomes and may reduce calcium oxalate deposition under antinutrient-rich conditions. These findings should be interpreted cautiously. Further well-designed, species-specific studies using standardized interventions and outcome measures are needed before firm conclusions can be drawn. *[CC BY — Open Access, verbatim with attribution.]*

Source: https://pubmed.ncbi.nlm.nih.gov/42313570/

• PMID 41897906 (2026, Animals : an open access journal from MDPI) — Dietary Protein Level in Late Gestation: Effects on Nutritional and Developmental Responses in Jennies and Their Foals.. Abstract (opening): This study evaluated the effects of dietary protein levels during late gestation on nutrient digestibility, plasma amino acid profiles in jennies, and donkey foal growth performance. Twenty-four pregnant jennies were randomly assigned to one of three diets with different crude protein (CP) contents during late gestation: 12.48% (HP), 11.52% (MP), and 10.54% (LP) on a dry matter basis. All animals received the same diet immediately after parturition for a duration of 30 days. During the trial, two digestion experiments were conducted, blood samples were collected at 28 and 7 days prepartum, and weekly weight measurements of jennies and foals were recorded. The results indicated that the dietary protein level did not significantly affect feed intake in late gestation. However, apparent nutrient digestibility of dry matter (DM), neutral detergent fiber (NDF), acid detergent fiber (ADF), crude protein (CP), and ether extract (EE), and calcium (Ca) and phosphorus (P) was generally higher in the MP and LP groups than in the HP group, with MP showing the most consistent improvements across nutrients and timepoints (<i>p</i> < 0.05). Although the HP diet increased plasma concentrations of certain amino acids, including glutamic acid (Glu), valine (Val), methionine (Met), leucine (Leu), essential amino acids (EAAs), functional amino acids (FAAs), and branched chain amino acids (BCAAs), and elevated serum levels of glucose (GLU), blood urea nitrogen (BUN), and creatinine (CRE), it failed to improve postpartum weight recovery in jennies, highlighting that weight dynamics during this period are governed by factors beyond dietary protein content alone. Specifically, the LP group exhibited significantly higher cumulative postpartum weight loss over weeks 1-4 than the HP group (<i>p</i> = 0.004). Regarding offspring performance, both HP and MP diets improved foal birth weight, weekly body weight up to 4 weeks, average daily gain, and body height compared to the LP group (<i>p</i> < 0.05), with no significant differences observed between the HP and MP groups. In conclusion, for jennies under the current confined feeding system, a late-gestation diet containing 11.52% CP was adequate to support higher nutrient digestibility in the jennies and better growth performance in their foals, compared to a lower protein level (10.54% CP). However, increasing the dietary CP to 12.48% provided no additional benefits in nutrient utilization or overall productivity. *[CC BY — Open Access, verbatim with attribution.]*

Source: https://pubmed.ncbi.nlm.nih.gov/41897906/

• PMID 42278097 (2026, Animals : an open access journal from MDPI) — The Effects of Arginine, Guanidinoacetic Acid and Citrulline Supplementation to Reduced Protein Diets for Aged Laying Hens.. Abstract (opening): This study evaluated the effects of arginine (Arg), guanidinoacetic acid (GAA), and citrulline (Cit) supplementation in reduced protein (RP) diets on the production performance, serum uric acid level and bone quality of aged laying hens. A total of 208 Hy-Line Brown laying hens from 60 to 75 weeks of age were assigned to eight dietary treatments, with 13 replicate cages per treatment and two hens per cage. Experimental diets comprised two protein levels (standard protein at 15.8% crude protein versus RP at 13.8% crude protein), and six RP diets supplemented with two inclusion levels (0.06% and 0.12%) of Arg, GAA, or Cit. Overall, increasing Cit supplementation improved productive performance compared with Arg and GAA, particularly by increasing egg weight (<i>p</i> = 0.048), egg mass (<i>p</i> = 0.019), and feed intake (<i>p</i> = 0.014) over the entire experimental period. In addition, Cit increased egg weight during 60-67 weeks (<i>p</i> = 0.049) and improved egg mass during 68-75 weeks (<i>p</i> = 0.014). Furthermore, supplementation of 0.12% Cit in RP diets significantly increased feed intake compared with standard protein (SP) and RP diets from 60 to 67 weeks (<i>p</i> < 0.001; one-way ANOVA). Both Cit and Arg supplementation increased yolk weight compared to GAA (<i>p</i> = 0.018). Further, Arg supplementation to the RP diet at 0.06% significantly increased energy digestibility compared to the SP and RP diets (<i>p</i> = 0.037). Increasing Arg and GAA levels reduced bone breaking strength compared with their respective low levels, whereas increasing Cit level enhanced tibia (<i>p</i> = 0.014) and femur (<i>p</i> = 0.006) bone breaking strength. Low-level GAA supplementation also increased tibia breaking strength. Thus, a moderate reduction in dietary protein level by two percentage points, combined with Cit supplementation at the high level (0.12%), was effective in enhancing egg mass, egg weight, yolk weight, and bone breaking strength in aged laying hens. These findings suggest that RP feeding strategies supplemented with functional Arg precursors may support productive efficiency, skeletal health, and nutrient utilization in late-lay hens. *[CC BY — Open Access, verbatim with attribution.]*

Source: https://pubmed.ncbi.nlm.nih.gov/42278097/

• PMID 41545880 (2026, BMC veterinary research) — Effects of supplementary protein source, autoclaving diets, and gender on biochemical blood parameters, oxidative stress markers, and caecal fermentation in rats.. Abstract (opening): BACKGROUND: The study aimed to assess the effects of supplementary protein source, thermal processing of diets, and gender on the health status of rats over a six-month-long feeding trial. The experiment was performed on 216 adult Crl:W (Han) Wistar rats, 108 males and 108 females, divided into nine groups fed a commercial SSNIFF (SN) diet or cereal-based diets containing soybean meal (SBM), or sodium caseinate (NaC) as a supplementary protein sources. The diets were non-autoclaved (T0), autoclaved at 121 °C for 20 min (T1), or autoclaved at 134 °C for 10 min (T2). RESULTS: Males displayed higher levels of amylase, phosphorus, glucose, and uric acid and lower levels of albumin, bilirubin, and iron in the blood than females. Males also experienced greater oxidative stress. In contrast, female rats had higher concentrations of short-chain fatty acids (SCFA) in the caecal digesta. Rats fed SBM and NaC diets had similar blood biochemical parameters, though NaC groups had higher cholesterol, triglycerides, and alanine aminotransferase levels. Oxidative stress markers were lower in rats fed SBM and NaC diets, which also aligned with increased SCFA concentrations in ceacal digesta in those animals. Autoclaved diets reduced feed intake and body weight gain and increased isoacids concentrations. CONCLUSION: The SBM diet appeared more beneficial than NaC diet due to an improvement in prooxidants-antioxidants balance and caecal fermentation. Feeding autoclaved diets reduced feed intake and body weight gain but had no negative impact on blood parameters and weights of internal organs. Autoclaving according to the T1 program can be recommended for laboratory animal breeding. Numerous interactions indicate a need for further studies to elucidate the mechanisms underlying different response of males and females to a diet. *[CC BY — Open Access, verbatim with attribution.]*

Source: https://pubmed.ncbi.nlm.nih.gov/41545880/

• PMID 41732551 (2026, Toxicology reports) — The toxicology of orally administered Δ&lt;sup&gt;9&lt;/sup&gt;-tetrahydrocannabinol in sheep.. Abstract (opening): <h4>Introduction</h4>As part of a larger study to assess the potential value of industrial hemp biomass (the low Δ⁹-tetrahydrocannabinol (Δ⁹-THC) variety of <i>Cannabis sativa</i> L.) as a feed for ruminants, a pharmacokinetics study of Δ⁹-THC, one of the main cannabinoids of interest, was undertaken. In undertaking this study, the toxicology of orally administered Δ⁹-THC was incidentally investigated and was discussed in the current paper.<h4>Methods</h4>Eight Merino ewes were administered with two <i>per os</i> (PO) doses of 88.5 mg Δ⁹-THC/kg bodyweight (BW) 12 h apart. Blood samples were taken periodically to determine the pharmacokinetics of Δ⁹-THC but also to check blood troponin I concentrations post dose administration as in the pharmacokinetics study there were adverse effects to the heart following intravenous administration of Δ⁹-THC.<h4>Results</h4>Following the PO dose of Δ⁹-THC, the pharmacokinetics were able to be determined (and were published separately); however, significant adverse clinical signs were observed in the sheep. Clinical signs included ataxia (stumbling, swaying), abnormal posture (head held low, head resting on the wall of the pen, back legs crossed over), somnolence, wool pulling, increased salivation, a prolonged reduction in feed intake and consequent decrease in BW. Plasma troponin I concentrations were elevated in three of the eight sheep following the PO dose of Δ⁹-THC.<h4>Conclusions</h4>The adverse clinical signs noted have implications for iHemp biomass as a potential feed for ruminants due to both animal health and production effects. Further research is required to investigate appropriate feeding strategies for iHemp biomass to be utilised as a feed for ruminants. *[CC BY — Open Access, verbatim with attribution.]*

Source: https://pubmed.ncbi.nlm.nih.gov/41732551/

• PMID 41868391 (2026, Frontiers in veterinary science) — Dietary energy levels regulate feed intake of broilers through the brain-gut axis.. Abstract (opening): <h4>Background</h4>Feed intake (FI) in broilers is significantly influenced by dietary energy levels through the brain-gut axis (BGA), profoundly affecting growth performance. The mechanisms underlying dietary energy regulation of FI and intestinal health via BGA remain unclear.<h4>Aim</h4>This study investigated the effects of low- (LED, 2,900 kcal/kg), medium- (MED, 3,200 kcal/kg), and high-energy diets (HED, 3,500 kcal/kg) on BGA function over 21 days.<h4>Results</h4>We found that increasing dietary energy reduced FI but increased body weight gain and improved feed conversion ratio. MED elevated anorexigenic hormones (serum CCK, hypothalamic POMC) and suppressed orexigenic hormones (serum orexin, hypothalamic AgRP and NPY). HED further enhanced anorexigenic signals (serum PYY, intestinal CCK and PYY) and strongly inhibited orexigenic factors. Both MED and HED activated the hypothalamic Rac1/PI3K/SF1 pathway, upregulating phosphorylated proteins and SF1 expression in the ventromedial hypothalamus. Importantly, MED promoted cecal microbiota balance, whereas HED impaired intestinal barrier function (ZO-1) and induced inflammation.<h4>Conclusion</h4>These results suggest that dietary energy levels modulate FI through BGA remodeling, integrating appetite hormones, hypothalamic signaling, and gut health, with high-energy diets increasing weight at the expense of intestinal integrity. Future studies could examine long-term effects and explore targeted interventions to maintain growth while protecting intestinal integrity under high-energy feeding. *[CC BY — Open Access, verbatim with attribution.]*

Source: https://pubmed.ncbi.nlm.nih.gov/41868391/

Source text: pdf-raw/evidence/europepmc_rat_mouse_nutrition_2026-08-01.txt (Europe PMC first-hand abstracts, pulled 2026-08-01).

License & attribution

Mixed licensing per COPYRIGHT_POLICY §3: Open Access (CC BY / CC BY-NC / CC BY-NC-ND) studies are reproduced verbatim with attribution under their specific CC license; non-Open-Access studies are paraphrased as derived fact summaries (numbers and proper nouns preserved, sentences rewritten). Original records:

• https://pubmed.ncbi.nlm.nih.gov/41545880/
• https://pubmed.ncbi.nlm.nih.gov/41732551/
• https://pubmed.ncbi.nlm.nih.gov/41868391/
• https://pubmed.ncbi.nlm.nih.gov/41897906/
• https://pubmed.ncbi.nlm.nih.gov/41961055/
• https://pubmed.ncbi.nlm.nih.gov/42169097/
• https://pubmed.ncbi.nlm.nih.gov/42278008/
• https://pubmed.ncbi.nlm.nih.gov/42278058/
• https://pubmed.ncbi.nlm.nih.gov/42278097/
• https://pubmed.ncbi.nlm.nih.gov/42313570/
• https://pubmed.ncbi.nlm.nih.gov/42320357/
• https://pubmed.ncbi.nlm.nih.gov/42514390/