Male Guinea Pigs Research Articles

Formulasi Hair Tonic Ekstrak Etanol Kulit Buah Pepaya (Carica Papaya L.) dan Uji Efektivitas Pertumbuhan Rambut pada Marmut Jantan (Cavia porcellus)

Hair for humans has an important role, in addition to protecting the skin from adverse environments, hair also plays an important role in a person's appearance. Losing a lot of hair due to hair loss can cause a lack of self-confidence, disappointment, and frustration, so it must be addressed immediately so as not to worsen the condition that can cause baldness. This study aims to determine whether there is a content of secondary metabolite compounds in fresh herbal medicine, herbal medicine powder and ethanol extract of papaya fruit skin; ethanol extract of papaya fruit skin (Carica papaya L.) can be formulated in the form of hair tonic preparations; whether the difference in concentration of ethanol extract of papaya fruit skin (Carica papaya L.) provides different activities in triggering hair growth in guinea pigs. This research method uses a quantitative approach and is experimental with independent variables, namely papaya fruit skin, herbal medicine, and ethanol extract of papaya fruit skin with concentrations of 10%, 20%, 30%. Research stages: phytochemical screening of fresh papaya fruit peel, powdered simplicia and ethanol extract, hair tonic formulation containing ethanol extract of papaya fruit peel 10%, 20% and 30%, hair tonic evaluation includes: organoleptic, viscosity, stability, pH, irritation, and preference test. And hair growth activity test on male guinea pigs. The results showed that the ethanol extract of papaya fruit peel contains alkaloids, flavonoids, saponins, steroids, and glycosides, can be formulated into hair tonic (EEKP) that meets physical quality requirements. Hair tonic EEKP 30% is the best because it has high hair growth activity, which is an average of 16.375 mm where this EEKP 30% hair tonic has almost the same hair growth activity as the positive control, which is an average of 16.782 mm.

Changes in choroidal thickness and blood flow in response to form deprivation-induced myopia and repeated low-level red-light therapy in Guinea pigs.

To evaluate ocular refractive development, choroidal thickness (ChT) and changes in choroidal blood flow in form-deprived myopia (FDM) Guinea pigs treated with repeated low-level red-light (RLRL) therapy. Twenty-eight 3-week-old male tricolour Guinea pigs were randomised into three groups: normal controls (NC, n = 10), form-deprived (FD, n = 10) and red light treated with form-deprivation (RLFD, n = 8). Interocular refraction and axial length (AL) changes were monitored. Optical coherence tomography angiography (OCTA) measured choroidal thickness, vessel area density, vessel skeleton density and blood flow signal intensity (flux) in the choriocapillaris and medium-large vessel layers. The experimental intervention lasted 3 weeks. At week 3, the FD group had higher myopia and longer axial length than the NC group (all p < 0.001). The RLFD group had higher hyperopia and shorter axial length than the FD group (all p < 0.001). At week 1, the NC group had a thicker choroidal thickness than the FD group (p < 0.05). At weeks 2 and 3, the RLFD group had a thicker choroidal thickness than the FD group (p = 0.002, p < 0.001, respectively). Additionally, the NC group had higher vessel area density, vessel skeleton density and flux in the choriocapillaris layer than the FD group at the three follow-up time points (all p < 0.05). At week 3, the vessel skeleton density and flux were higher in the RLFD group than in the FD group (all p < 0.05). Correlation analysis results showed that weekly changes in refraction and choroidal thickness were negatively correlated with changes in axial length (all p < 0.05). Choroidal thickness changes were positively correlated with alterations in the vessel area density, vessel skeleton density and flux in the choriocapillaris layer, as well as vessel skeleton density and flux changes in the medium-large vessel layers (all p < 0.05). Repeated low-level red-light (RLRL) therapy retards FDM progression in Guinea pigs, potentially through increased choroidal blood flow in the choriocapillaris layer.

Toxicological evaluation of combination products containing imidacloprid, moxidectin and pyriproxyfen

The purpose of the research is to investigate subacute cutaneous toxicity in rats, allergenic properties in guinea pigs and tolerance of increased doses of drugs based on imidacloprid, moxidectin and pyriproxyfen by dogs and cats of different age groups.Materials and methods. Toxicological studies (subacute cutaneous toxicity, study of allergenic properties) were conducted in the vivarium of the All-Russian Research Institute of Plant Protection, a branch of the Federal Scientific Center for Experimental Veterinary Medicine of the Russian Academy of Sciences, on male rats and guinea pigs. Experiments on the tolerance of drugs by target animal species (dogs, cats) were conducted in the Podolsk department of the All-Russian Research Institute of Plant Protection. The choice of doses, frequency and methods of administration of the studied drugs were determined in accordance with the Guidelines for Experimental (Preclinical) Study of New Pharmacological Substances. All doses were calculated for the drug taking into account the density (1.08 g/cm3).Results and discussion. When studying the acute cutaneous toxicity of the drug on rats, LD50 exceeded the maximum possible dose of 10 000 mg/kg (hazard class 4 according to GOST 12.1.007-76). In a subacute experiment on rats, it was established that doses of 1000 and 500 mg/kg are ineffective (safe), the threshold and toxic doses could not be established. These drugs, when treating animals 8 times with an interval of 3 days in a three- and five-fold increase in the maximum therapeutic dose during the experimental period, did not have a negative effect on the general condition of the animals, their physiological status and behavior; no statistically significant changes in the morphological and biochemical parameters of the blood, physicochemical parameters of urine were noted in animals from the experimental groups compared to the control. However, in one adult dog from the second experimental group, which was used a five-fold increase in the maximum therapeutic dose of the drug, depression was noted on the 20th day of the experiment. The physiological state of the animal returned to normal within 24 hours voluntarily without the use of symptomatic therapy.

Food Preference and Demand in a Ramp Task in Guinea Pigs (Cavia porcellus)

Guinea pigs (Cavia porcellus) are popular pets and used as laboratory animals, however, their dietary preferences are under-studied. It is important for guinea pig owners and carers to increase the opportunity for good animal welfare by providing personalized and enriching dietary options. Thus, this study aimed to assess the use of paired-stimulus and multiple-stimulus-without-replacement preference assessments to determine the food preferences of seven male guinea pigs and test the validity of the methods by testing the demand for the most- and least preferred foods as reinforcers for climbing an elevated ramp. Generally, the preference assessments identified the same foods as the most preferred for each guinea pig, but not the least preferred foods. Guinea pigs climbed up to the steepest angle for both most and least preferred foods, but a non-linear least squares regression and demand analysis indicated faster climbing and inelastic demand for most preferred foods compared to slower climbing and elastic demand for least preferred foods. Both preference assessment methods were valid in identifying a preferred food, however, the multiple-stimulus-without-replacement assessment was more efficient to conduct. High-preference foods such as parsley and dandelion are recommended as future training reinforcers for guinea pigs and as foods to consider using as enrichment in captive guinea pig systems to encourage good welfare.

Pulmonary surfactant and prostaglandin E2 in airway smooth muscle relaxation of human and male guinea pigs.

Pulmonary surfactant serves as a barrier to respiratory epithelium but can also regulate airway smooth muscle (ASM) tone. Surfactant (SF) relaxes contracted ASM, similar to β2-agonists, anticholinergics, nitric oxide, and prostanoids. The exact mechanism of surfactant relaxation and whether surfactant relaxes hyperresponsive ASM remains unknown. Based on previous research, relaxation requires an intact epithelium and prostanoid synthesis. We sought to examine the mechanisms by which surfactant causes ASM relaxation. Organ bath measurements of isometric tension of ASM of guinea pigs in response to exogenous surfactant revealed that surfactant reduces tension of healthy and hyperresponsive tracheal tissue. The relaxant effect of surfactant was reduced if prostanoid synthesis was inhibited and/or if prostaglandin E2-related EP2 receptors were antagonized. Atomic force microscopy revealed that human ASM cells stiffen during contraction and soften during relaxation. Surfactant softened ASM cells, similarly to the known bronchodilator prostaglandin E2 (PGE2) and the cell softening was abolished when EP4 receptors for PGE2 were antagonized. Elevated levels of PGE2 were found in cultures of normal human bronchial epithelial cells exposed to pulmonary surfactant. We conclude that prostaglandin E2 and its EP2 and EP4 receptors are likely involved in the relaxant effect of pulmonary surfactant in airways.

Evaluación comparativa de un suplemento alimenticio artesanal y cuatro balanceados comerciales sobre la eficiencia productiva de cuyes parrilleros

The aim of this study was to evaluate the productive performance of growing guinea pigs, fed with green alfalfa forage and an artisanal supplement widely spread in the Mantaro Valley, Peru, made from wheat byproduct, whole yellow corn and soy cake in the base ratio of 3:2:1, compared to four commercial feeds, in terms of weight gain (BWG), feed conversion (FC), carcass yield (CY), and economic merit. In total, 60 male and female red-line guinea pigs, 18 ± 3 days old and weighing 318 ± 35 g, were used. They were distributed in five metal cages with four levels each. A randomized Complete Block Design was used considering sex as a block. The effect achieved by the artisanal supplement on BWG, FC and CY were similar to that achieved by two commercial products, but superior to the other two; however, it showed a better economic return in terms of unit profit margin and relative profitability due to the lower food cost recorded. It is concluded that the artisanal formulation is appropriate to be used in the fattening of guinea pigs due to its easy preparation and effectiveness in achieving an adequate productive response and greater economic remuneration.

Metabolic rate and saliva cortisol concentrations in socially housed adolescent guinea pigs

An individual’s energetic demands and hence metabolic rate can strongly change during adolescence, a phase characterized by profound morphological, physiological, and endocrine changes. Glucocorticoid hormones (e.g. cortisol) are released in response to hypothalamic–pituitary–adrenal–axis activity, modulate several metabolic processes, and can also be linked to increased metabolic rate. In domestic guinea pigs (Cavia aperea f. porcellus) housed in same-sex groups, cortisol concentrations increase during adolescence in males but remain stable in females, which was suggested to be related to different energetic demands by age. We therefore measured metabolic rate through oxygen (O2) consumption over 2.5 h in male and female guinea pigs housed in same-sex groups during adolescence at ages of 60, 120, and 180 days, which was paralleled by analyses of saliva cortisol concentrations before and after the measurement. The statistical analyses involved whole body metabolic rate (ml O2/h), body mass-corrected metabolic rate (ml O2/h/kg), and body mass-independent metabolic rate (ml O2/h statistically corrected for body mass). We found increasing cortisol concentrations with age in males only, but none of the three metabolic rate analyses revealed a sex difference by age. On the individual level, repeatability across ages was found in metabolic rate as well as in body mass and cortisol concentrations after the measurement, but not in “basal” cortisol concentrations. Our results suggest no sex-specific changes in metabolic rate and hence equal energetic demands in male and female guinea pigs during adolescence. Moreover, metabolic rate clearly represents a highly stable physiological trait already early in a guinea pig’s life irrespective of rather fluctuating cortisol concentrations.

Removal of the infrapatellar fat pad and associated synovium benefits female guinea pigs in the Dunkin Hartley model of idiopathic osteoarthritis.

Several tissues contribute to the onset and advancement of knee osteoarthritis (OA). One tissue type that is worthy of closer evaluation, particularly in the context of sex, is the infrapatellar fat pad (IFP). We previously demonstrated that removal of the IFP had short-term beneficial effects for a cohort of male Dunkin-Hartley guinea pigs. The present project was designed to elucidate the influence of IFP removal in females of this OA-prone strain. It was hypothesized that resection of the IFP would reduce the development of OA in knees of a rodent model predisposed to the disease. Female guinea pigs (n=16) were acquired at an age of 2.5 months. Surgical removal of the IFP and associated synovium complex (IFP/SC) was executed at 3 months of age. One knee had the IFP/SC resected; a comparable sham surgery was performed on the contralateral knee. All animals were subjected to voluntary enclosure monitoring and dynamic weight-bearing, as well as compulsory treadmill-based gait analysis monthly; baseline data was collected prior to surgery. Guinea pigs were euthanized at 7 months. Knees from eight animals were evaluated via histology, mRNA expression, and immunohistochemistry (IHC); knees from the remaining eight animals were allocated to microcomputed tomography (microCT), biomechanical analyses (whole joint testing and indentation relaxation testing), and atomic absorption spectroscopy (AAS). Fibrous connective tissue (FCT) replaced the IFP/SC. Mobility/gait data indicated that unilateral IFP/SC removal did not affect bilateral hindlimb movement. MicroCT demonstrated that osteophytes were not a significant feature of OA in this sex; however, trabecular thickness (TbTh) in medial femorae decreased in knees containing the FCT. Histopathology scores were predominantly influenced by changes in the lateral tibia, which demonstrated that histologic signs of OA were increased in knees containing the native IFP/SC versus those with the FCT. Similarly, indentation testing demonstrated higher instantaneous and equilibrium moduli in the lateral tibial articular cartilage of control knees with native IFPs. AAS of multiple tissue types associated with the knee revealed that zinc was the major trace element influenced by removal of the IFP/SC. Our data suggest that the IFP/SC is a significant component driving knee OA in female guinea pigs and that resection of this tissue prior to disease has short-term benefits. Specifically, the formation of the FCT in place of the native tissue resulted in decreased cartilage-related OA changes, as demonstrated by reduced Osteoarthritis Research Society International (OARSI) histology scores, as well as changes in transcript, protein, and cartilage indentation analyses. Importantly, this model provides evidence that sex needs to be considered when investigating responses and associated mechanisms seen with this intervention.

The effects of pearl oyster shell-derived bone grafts on TNF-alfa levels: An in vivo study in Cavia porcellus

Abstract Objective: This study aims to assess the effect of bone graft materials derived from pearl oyster shells on the tumor necrosis factor-alpha (TNF-α) level. Methods: This research utilized a bone graft containing hydroxyapatite Pinctada maxima (HPM) powder obtained from pearl oyster shells. Material testing was conducted on 30 male guinea pigs aged 8-10 weeks, divided into three groups: the negative control group, the group treated solely with HPM, and the group treated with HPM combined with platelet-rich fibrin (PRF). Each treatment group was observed for 7 and 14 days. The results were analyzed using One-way ANOVA with a significance level of p&lt;0.05. Results: The findings demonstrated a decrease in the average TNF-α levels across all groups. On observation days 7 and 14, the HPM group exhibited a significant difference compared to the negative control group, indicating reduced TNF-α levels. However, no significant difference was observed when comparing the HPM group with the HPM and PRF groups. Conclusions: Bone grafts derived from pearl oyster shells possess high levels of hydroxyapatite, and the addition of PRF into the bone graft effectively reduces TNF-α.

The entrainment of action potential duration and contraction amplitude by recapitulation of respiratory sinus arrhythmia in isolated cardiac myocytes

Abstract Introduction Respiratory sinus arrhythmia (RSA) is the oscillation of heart rate in phase with ventilation and represents the high frequency component of heart rate variability. RSA is prevalent in the young and the endurance-trained and its loss is considered a prognostic indicator for sudden cardiac death. The recapitulation of RSA improves cardiac function in animal models of heart failure1,2. However, the precise mechanisms by which RSA affects cardiac function are unknown. Hypothesis: We examined the hypothesis that the recapitulation of RSA in isolated ventricular myocytes affects the stimulus interval-dependence of action potential duration (APD) and sarcomere shortening through mechanisms involving sarcoplasmic reticulum (SR) Ca2+ release. Methods Hearts were excised from adult male guinea pigs under general anaesthesia (140 mg/kg bodyweight euthatal, i.p.) and left ventricular myocytes isolated. Isolated myocytes were superfused with Tyrode’s solution for perforated patch whole-cell current clamp recording and action potentials and sarcomere length measured simultaneously. Sample sizes are presented as n/N (cell/animal number) and nested hierarchical analysis applied using a generalized linear mixed model (P&amp;lt;0.05). Results Pacing at a basic cycle length (CL, 350 ms) induced APD, Ca2+ transient amplitude (CaT) and sarcomere shortening alternans. The recapitulation of RSA through oscillatory pacing (OP), in which CL was set to 20% below and 20% above the corresponding basic CL in a 2-short, 2-long stimulus train, reduced the incidence of alternans. Furthermore, OP entrained APD, CaT and sarcomere shortening and this entrainment persisted in voltage clamp experiments with fixed APD. Using a three-step protocol to examine the dependence of APD and sarcomere shortening on both preceding (CLn-1) and anteceding (CLn-2) stimulus intervals, both APD and sarcomere shortening were found to depend directly on the preceding cycle length (CLn-1, P&amp;lt;0.001). In contrast, sarcomere shortening depended inversely on the anteceding CL (CLn-2, P&amp;lt;0.001; n/N = 24/4). Following treatment of the cells with caffeine (50 µM) to sensitise ryanodine receptors, the dependence of APD and sarcomere shortening on CLn-1 was markedly suppressed, and the inverse dependence of sarcomere shortening on CLn-2 was lost (P&amp;lt;0.001, n/N = 6/3). The effects of OP are akin to post-extrasystolic potentiation3 and mathematical simulation4 supports the involvement of changes in the sarcoplasmic reticulum Ca2+ content. Conclusion These data are consistent with an obligatory role for the SR in the entrainment of APD, CaT and sarcomere shortening and the suppression of alternans by the recapitulation of RSA. We hypothesise that recapitulation of RSA would be protective against ventricular tachyarrhythmia and further work is required to test this.

Antifungal activity of aminopyrrolnitrin against Trichophyton verrucosum in a guinea pig model of dermatophytosis.

Dermatophytosis is a common and major public health concern worldwide. Despite the increasing availability of antifungal drugs, relapses and untreated cases of dermatophyte infections are reported. Therefore, novel antifungal agents are required. Aminopyrrolnitrin (APRN) shows promise for dermatophytosis treatment because of its antifungal activity. This study aimed to assess the antifungal properties of APRN against Trichophyton verrucosum (T. verrucosum), in both laboratory settings and a guinea pig model. The minimum inhibitory concentrations (MICs) of APRN and enilconazole against T. verrucosum were determined according to the CLSI M38 method. The skins of 16 male guinea pigs were infected with 1.0 × 108 conidia of T. verrucosum and the animals were grouped into sets of four: negative control group (NC) received normal saline; positive control group (PC) received 2 μg/mL of enilconazole; and APRN4 and APRN8 received 4 and 8 μg/mL of APRN, respectively. Clinical, mycological and histological efficacies were measured after 10 days. The MIC90 of APRN and enilconazole against T. verrucosum was 4 and 2 μg/mL, respectively. The clinical scores of PC, APRN4, and APRN8 were significantly lower than those of NC. Clinical and mycological efficacies were higher for APRN8, APRN4 and PC. No fungi were observed in the skin tissues of APRN4 and APRN8, while fungi were observed in 50% of the PC. APRN showed antifungal activity against T. verrucosum invitro and invivo and is a potential candidate for the treatment of dermatophytosis.

Testosterone Enhances KV Currents and Airway Smooth Muscle Relaxation Induced by ATP and UTP through P2Y4 Receptors and Adenylyl Cyclase Pathway.

Numerous studies suggest the involvement of adenosine-5'-triphosphate (ATP) and similar nucleotides in the pathophysiology of asthma. Androgens, such as testosterone (TES), are proposed to alleviate asthma symptoms in young men. ATP and uridine-5'-triphosphate (UTP) relax the airway smooth muscle (ASM) via purinergic P2Y2 and P2Y4 receptors and K+ channel opening. We previously demonstrated that TES increased the expression of voltage-dependent K+ (KV) channels in ASM. This study investigates how TES may potentiate ASM relaxation induced by ATP and UTP. Tracheal tissues treated with or without TES (control group) from young male guinea pigs were used. In organ baths, tracheas exposed to TES (40 nM for 48 h) showed enhanced ATP- and UTP-evoked relaxation. Tetraethylammonium, a K+ channel blocker, annulled this effect. Patch-clamp experiments in tracheal myocytes showed that TES also increased ATP- and UTP-induced K+ currents, and this effect was abolished with flutamide (an androgen receptor antagonist). KV channels were involved in this phenomenon, which was demonstrated by inhibition with 4-aminopyridine. RB2 (an antagonist of almost all P2Y receptors except for P2Y2), as well as N-ethylmaleimide and SQ 22,536 (inhibitors of G proteins and adenylyl cyclase, respectively), attenuated the enhancement of the K+ currents induced by TES. Immunofluorescence and immunohistochemistry studies revealed that TES did not modify the expression of P2Y4 receptors or COX-1 and COX-2, while we have demonstrated that this androgen augmented the expression of KV1.2 and KV1.5 channels in ASM. Thus, TES leads to the upregulation of P2Y4 signaling and KV channels in guinea pig ASM, enhancing ATP and UTP relaxation responses, which likely limits the severity of bronchospasm in young males.

Brimonidine as a possible treatment for myopia

BackgroundMyopia is becoming a huge burden on the world’s public health systems. The purpose of this study was to explore the effect of brimonidine in the treatment of form-deprivation myopia (FDM) and the relationship between intraocular pressure (IOP) and myopia development.MethodsMonocular form deprivation myopia (FDM) was induced in three-week-old pigmented male guinea pigs. They were treated with 3 different methods of brimonidine administration (eye drops, and subconjunctival or intravitreal injections). Four different concentrations of brimonidine were tested for each method (2µg/µL, 4µg/µL, 20µg/µL, and 40µg/µL). All treatments continued for a period of 21 days. Tonometry, retinoscopy, and A-scan ultrasonography were used to monitor intraocular pressure, refractive error and axial length (AL), respectively.ResultsTreatment with subconjunctival brimonidine at 40µg/µL, and intravitreal brimonidine at 2µg/µL and 4µg/µL, inhibited the development of FDM. The myopic refraction, excessive axial length, and elevation of IOP were significantly decreased. Brimonidine in eye drops was ineffective.ConclusionBrimonidine at appropriate doses significantly reduced the development of FD myopia in guinea pigs. The IOP may change with FD myopia.

The Nutritional Value of Biowaste Bovine Slaughterhouse Meals for Monogastric Species Feeding: The Guinea Pig as an Animal Model.

Biowaste from slaughterhouses can be recovered to benefit food security and reduce contamination potential. More than 3 billion heads of livestock are consumed worldwide, which will increase by 17% by 2028, generating more biowaste, increasing infectious agents, and causing economic losses due to circular economy principles not being applied. This work evaluated the nutritional quality of four types of biowaste from bovine slaughter which were transformed into a meal for guinea pigs (rumen content (RCM), ears (EaM), blood (BM), and cheeks (CM)) according to their chemical composition, digestible components, energy contribution, and voluntary consumption. For the animal model, adult male guinea pigs were arranged in metabolic cages for feces collection without urinary contamination. Nine guinea pigs were used in each digestibility test. First, a direct digestibility test was conducted using a meal of barley as a reference diet (RD), the indigestibility coefficient of which allowed for the estimation of the digestibility of biowaste meals through indirect calculations; for this, diets composed of 80% of the RD and 20% of the corresponding biowaste meals were evaluated. The difference method was suitable for determining the digestibility of beef biowaste using the indigestibility coefficients of the reference diet to calculate the digestibility of ingredients which could not be offered as 100% of the meal but were incorporated as 20%. The digestible protein and metabolizable energy contents of RCM, EaM, BM, and CM were 10.2% and 2853 kcal/kg, 44.5% and 3325 kcal/kg, 70.7% and 2583 kcal/kg, and 80.8% and 3386 kcal/kg, respectively. The CM and BM feeds had the highest contributions of digestible protein due to their higher nitrogen content, and the CM and EaM feeds had the highest ME contents due to their higher fat contents. The biowaste meal consumption in descending order was CM > RCM > EaM > BM, which were consumed without problems. These results are indicative that these components can be part of guinea pigs' diets, and it is recommended to continue studies into guinea pig growth and fattening diets with different levels of these biowaste meals.

Efecto de la biofertilización en la biomasa de alfalfa y engorde de cuyes

En la sierra peruana, la producción de alfalfa y el engorde de cuyes enfrentan problemas que impactan la economía de los criadores. Un estudio en el Caserío de Coñaica (Panao, Pachitea, Huánuco) se llevó a cabo para evaluar el impacto de la biofertilización en la biomasa de alfalfa y el engorde de cuyes. Se implementaron dos diseños experimentales: DBCA para medir la biomasa de alfalfa y DCA para estudiar el engorde de cuyes destetados (machos y hembras). Los tres tratamientos evaluados fueron: aplicación de microorganismos eficaces (EM) al follaje (T1), EM al suelo (T2) y un grupo de control sin EM, con dosis del 10% cada 15 días. La alfalfa biofertilizada se utilizó como alimento para los cuyes machos y hembras durante nueve semanas. Se distinguió que el tratamiento de EM al follaje incrementó significativamente la biomasa de la alfalfa y afectó favorablemente al engorde de los cuyes, aunque solo se evidenció una mejora significativa en la conversión alimenticia de los cuyes machos. Estos resultados indican que las aplicaciones de EM al follaje con una dosis del 10% cada 15 días promueven una mayor productividad en la alfalfa y benefician el proceso de engorde de los cuyes.

Analysis and 3D Imaging of Morphometric - Mineral Structure Changes in Skulls of Male and Female Guinea Pigs During and After Developmental Period

Analysis and 3D Imaging of Morphometric - Mineral Structure Changes in Skulls of Male and Female Guinea Pigs During and After Developmental Period

Administration of 12.5% Strawberry Ethanol Extract Cream Reduced Tyrosinase Enzyme and Melanin Amount in Male Guinea Pig Skin Exposed to UVB with More Potential for Protection than Treatment

Administration of 12.5% Strawberry Ethanol Extract Cream Reduced Tyrosinase Enzyme and Melanin Amount in Male Guinea Pig Skin Exposed to UVB with More Potential for Protection than Treatment

Establishing New Isosexual Pairs in Adult Male Guinea Pigs (Cavia porcellus) to Facilitate Social Housing.

Guinea pigs (Cavia porcellus) are a commonly used species in biomedical research. As social creatures, compatible guinea pigs should be housed together unless scientific objectives or veterinary care require otherwise. Extensive literature suggests that adult male guinea pigs are highly aggressive in the presence of females, but data are lacking regarding the compatibility of cohoused adult males in the absence of females. Most studies that use adult males do not report housing densities. We used serial wound scoring and observations of behavior to determine whether unfamiliar adult male guinea pigs will develop stable, prosocial isosexual pairs. Wound scoring was performed before and 24 h after pairing. Serial behavioral observations assessed affiliative and agonistic behaviors at 0.5, 2, 24, and 48 h after pairing. Wound scoring and behavioral observations continued weekly for 1 mo and monthly thereafter. Wound scores were significantly higher at 24 h after pairing as compared with baseline and all other time points. Wounding was rare after week 2, indicating reduced aggression. Furthermore, affiliative behaviors significantly increased over time while agonistic behaviors were rare. Together, these data suggest that unfamiliar adult male guinea pigs establish stable prosocial pairs after an acclimation period. As was done in the present study, providing ample space, separate shelters for each animal, and the absence of female guinea pigs will likely facilitate successful pairing. We recommend consideration of a social housing program for adult male guinea pigs to provide companionship and enrich their housing environment.

CURVA DE CRECIMIENTO DE CUYES MACHOS (Cavia porcellus) DE LA RAZA PERÚ MEDIANTE MODELOS NO LINEALES EN COLOMBIA

&lt;p&gt;&lt;strong&gt;Background&lt;/strong&gt;: Animal growth modeling is a tool that enables the acquisition of parameters to evaluate animal performance and predict outcomes for decision-making. &lt;strong&gt;Objective:&lt;/strong&gt; To describe the growth of male guinea pigs of the Peruvian breed using the non-linear Brody, Gompertz, Logistic, and Von Bertalanffy models. &lt;strong&gt;Methodology&lt;/strong&gt;: Twelve male guinea pigs with an initial weight of 393 ± 55 g were housed in metabolic cages with &lt;em&gt;ad libitum&lt;/em&gt; feeding of a complete pellet diet. They were weighed every seven days for 13 weeks until reaching 1197 ± 84 g. Criteria used to assess the model's fitting ability included the Akaike Information Criterion (AIC), Bayesian Information Criterion (BIC), coefficient of determination (R&lt;sup&gt;2&lt;/sup&gt;), concordance correlation coefficient (CCC), and mean squared prediction error (CMEP). &lt;strong&gt;Results:&lt;/strong&gt; The Logistic model consistently predicted maturity weight (1421g), initial weight (187g), age (65 days), and weight (711g) at the growth curve inflection point. Gompertz and Von Bertalanffy's models tended to overestimate adult weight (A) and exhibited the lowest maturity index (k). Among Gompertz, Logistic, and Von Bertalanffy models, AIC, BIC, R&lt;sup&gt;2&lt;/sup&gt;, CCC, and CMEP fitting criteria showed no significant differences (p &amp;gt; 0.05). &lt;strong&gt;Implications:&lt;/strong&gt; The Brody model was the only one with biologically inconsistent parameters. &lt;strong&gt;Conclusion&lt;/strong&gt;: Considering the biological significance of parameters and residual analysis, the Logistic model is more suitable for describing the growth curve of male guinea pigs of the Peruvian breed.&lt;strong&gt;&lt;em&gt;&lt;/em&gt;&lt;/strong&gt;&lt;/p&gt;

Mice, rats, and guinea pigs differ in FMOs expression and tissue concentration of TMAO, a gut bacteria-derived biomarker of cardiovascular and metabolic diseases.

Increased plasma trimethylamine oxide (TMAO) is observed in cardiovascular and metabolic diseases, originating from the gut microbiota product, trimethylamine (TMA), via flavin-containing monooxygenases (FMOs)-dependent oxidation. Numerous studies have investigated the association between plasma TMAO and various pathologies, yet limited knowledge exists regarding tissue concentrations of TMAO, TMAO precursors, and interspecies variability. Chromatography coupled with mass spectrometry was employed to evaluate tissue concentrations of TMAO and its precursors in adult male mice, rats, and guinea pigs. FMO mRNA and protein levels were assessed through PCR and Western blot, respectively. Plasma TMAO levels were similar among the studied species. However, significant differences in tissue concentrations of TMAO were observed between mice, rats, and guinea pigs. The rat renal medulla exhibited the highest TMAO concentration, while the lowest was found in the mouse liver. Mice demonstrated significantly higher plasma TMA concentrations compared to rats and guinea pigs, with the highest TMA concentration found in the mouse renal medulla and the lowest in the rat lungs. FMO5 exhibited the highest expression in mouse liver, while FMO3 was highly expressed in rats. Guinea pigs displayed low expression of FMOs in this tissue. Despite similar plasma TMAO levels, mice, rats, and guinea pigs exhibited significant differences in tissue concentrations of TMA, TMAO, and FMO expression. These interspecies variations should be considered in the design and interpretation of experimental studies. Furthermore, these findings may suggest a diverse importance of the TMAO pathway in the physiology of the evaluated species.