Status Of Guinea Pigs Research Articles

Comparative efficacy of zinc supplementation from different sources on nutrient digestibility, hemato-biochemistry and anti-oxidant activity in guinea pigs

Abstract Nanominerals are recently advocated for replacing their organic and inorganic counterparts. To examine their comparative efficacy, a study was designed to investigate the effect of supplementation of zinc through different sources and forms on apparent digestibility of nutrients, body weight gain, blood hemato-biochemistry, anti-oxidant activity, and serum mineral status in guinea pigs ( Cavia porcellus ). Groups (T 1 , control (inorganic zinc; ZnSO 4 ); T 2 , organic Zn (Zn methionine), commercial zinc nanoparticle (T 3 ), two zinc nanoparticles prepared in our laboratory (T 4 , T 5 ), were formed with six guinea pigs in each group (289 ± 3.5 g body weight) in a randomized block design. They were supplemented with 20 mg Zn per kg feed on dry matter basis for 90 days. At the end of the experiment, blood samples were collected from each animal through cardiac puncture and analyzed for hemato-biochemistry, oxidants/anti-oxidants, thyroid hormones and serum minerals. The results showed that intake and digestibility of nutrients were not affected by source of supplementation. Oxidants/anti-oxidants, thyroid hormones, hemato-biochemistry and serum minerals were also not affected by source of supplementation. However, the growth rate was higher (P = 0.031) in commercial nano-Zn supplemented groups (T 3 ) than in the other groups. Thus, supplementation of 20 ppm commercial Zn nanoparticles had a positive effect on growth rate of guinea pigs. But supplementation of Zn increased erythrocytic SOD activity and serum zinc level, irrespective of the source of Zn. As evidenced in our study spanning 90 days of trial, zinc nanoparticles can be safely supplemented up to 20 ppm level in the diet of guinea pigs.

Blood biochemistry, thyroid hormones, and oxidant/antioxidant status of guinea pigs challenged with sodium arsenite or arsenic trioxide.

The present experiment aimed to compare the two most commonly used compounds of arsenic (sodium arsenite and arsenic trioxide) for their effect on blood metabolites, thyroid hormones, and oxidant/antioxidant status in guinea pigs. Twenty-one adult guinea pigs were randomly divided into three equal groups. Animals in group T1 (control) were fed a basal diet, whereas 50 ppm arsenic was added in the basal diet either as sodium arsenite (T2) or arsenic trioxide (T3) and fed for 11 weeks. Serum aspartate aminotransferase and alanine aminotransferase activities were significantly increased along with a decrease in blood hemoglobin level in both the arsenic-administered groups. The level of erythrocytic antioxidants (catalase, superoxide dismutase, reduced glutathione, glutathione-S-transferase, and glutathione reductase) was decreased and lipid peroxidation was elevated upon arsenic exposure. Serum thyroid hormone levels were reduced and arsenic levels in tissues increased in both the arsenic-exposed groups, irrespective of the arsenic compound. Thus, sodium arsenite and arsenic trioxide exerted similar adverse effects on blood metabolic profile, antioxidant status, and thyroid hormones in guinea pigs.

High dietary fat and cholesterol exacerbates chronic vitamin C deficiency in guinea pigs

Vitamin C deficiency - or hypovitaminosis C defined as a plasma concentration below 23μm - is estimated to affect hundreds of millions of people in the Western world, in particular subpopulations of low socio-economic status that tend to eat diets of poor nutritional value. Recent studies by us have shown that vitamin C deficiency may result in impaired brain development. Thus, the aim of the present study was to investigate if a poor diet high in fat and cholesterol affects the vitamin C status of guinea pigs kept on either sufficient or deficient levels of dietary ascorbate (Asc) for up to 6 months with particular emphasis on the brain. The present results show that a high-fat and cholesterol diet significantly decreased the vitamin C concentrations in the brain, irrespective of the vitamin C status of the animal (P<0·001). The brain Asc oxidation ratio only depended on vitamin C status (P<0·0001) and not on the dietary lipid content. In plasma, the levels of Asc significantly decreased when vitamin C in the diet was low or when the fat/cholesterol content was high (P<0·0001 for both). The Asc oxidation ratio increased both with low vitamin C and with high fat and cholesterol content (P<0·0001 for both). We show here for the first time that vitamin C homoeostasis of brain is affected by a diet rich in fat and cholesterol. The present findings suggest that this type of diet increases the turnover of Asc; hence, individuals consuming high-lipid diets may be at increased risk of vitamin C deficiency.

Expression of interferon‐γ and tumour necrosis factor‐α messenger RNA does not correlate with protection in guinea pigs challenged with virulent Mycobacterium tuberculosis by the respiratory route

Cytokine messenger RNA (mRNA) expression was investigated in the spleen and lung digest cells of bacillus Calmette-Guérin (BCG)-vaccinated and non-vaccinated guinea pigs following low-dose, pulmonary exposure to virulent Mycobacterium tuberculosis. After purified protein derivative (PPD) stimulation, the levels of lung cell interferon-gamma (IFN-gamma), tumour necrosis factor-alpha (TNF-alpha) and spleen cell interleukin-12 (IL-12) p40 mRNAs were significantly increased in the non-vaccinated M. tuberculosis-infected guinea pigs compared to the BCG-vaccinated guinea pigs. In contrast, the expression of anti-inflammatory transforming growth factor-beta and IL-10 mRNAs was significantly enhanced in the spleens of BCG-vaccinated animals. Despite the presence of protective cytokine mRNA expression, the non-vaccinated guinea pigs had significantly higher lung and spleen bacterial burdens. In contrast, BCG-vaccinated guinea pigs controlled the bacterial multiplication in their lungs and spleens, indicating that both protective as well as anti-inflammatory cytokine responses are associated with a reduction in bacteria. In addition, lung digest cells from non-vaccinated guinea pigs contained a significantly higher percentage of neutrophils, CD3(+) and CD8(+) T cells, while the percentage of macrophages was increased in the BCG-vaccinated animals. Total and purified lung digest T cells co-cultured with lung macrophages (LMøs) proliferated poorly after PPD stimulation in both non-vaccinated and BCG-vaccinated animals while robust proliferation to PPD was observed when T cells were co-cultured with peritoneal macrophages (PMøs). Macrophages within the lung compartment appear to regulate the response of T cells irrespective of the vaccination status in guinea pigs. Taken together, our results suggest that type I cytokine mRNA expression is not associated with vaccine-induced protection in the low-dose guinea pig model of tuberculosis.

Non-invasive measurement of adrenocortical and gonadal activity in male and female guinea pigs (Cavia aperea f. porcellus)

Taking blood samples is a common method in biomedical and biological research using guinea pigs. However, most blood sampling techniques are complicated and highly invasive and may therefore not be appropriate for certain research topics concerning stress and reproduction. Thus, a non-invasive method to measure steroid hormones is critically needed. The aim of this study was the biological validation of corresponding enzyme immunoassays for the measurement of fecal cortisol, progesterone, estrogen, and testosterone metabolites in guinea pigs. We examined the effect of subcutaneous injections of ACTH or saline on fecal cortisol metabolites to investigate the suitability of fecal samples to monitor adrenocortical activity. Furthermore, we investigated whether fecal sex steroid metabolites accurately reflected endocrine changes observed in plasma samples during female estrous cycles and male puberty, respectively. In addition, we compared fecal testosterone metabolites of intact males, castrated males, and females to investigate the reliability of fecal samples in discriminating gonadal status of males. Concentrations of fecal cortisol metabolites were significantly increased following ACTH challenge, indicating that adrenocortical activity can be monitored via fecal samples. Secondly, in females, plasma and fecal gonadal steroids were significantly correlated in most subjects. The assay for testosterone metabolites, on the other hand, could not clearly discriminate between test groups. From these findings we conclude that fecal samples can be used for the non-invasive assessment of adrenocortical and female reproductive status in guinea pigs. Testosterone metabolism seems to be more complex and further investigations are needed to establish a more suitable assay.

Vitamin C and vitamin E status in guinea pig tissues following estrogen administration

Previous studies reported lower tissue vitamin C levels in rats following estrogen administration. This study examined the effects of two weeks of daily estrogen administration (40 μg β-estradiol 3-benzoate per kg BW) on tissue vitamin C status in male and female guinea pigs, who unlike rats, require dietary vitamin C. Estrogen administration resulted in significant vitamin C loss in heart and liver from both genders and in plantaris muscle from male guinea pigs. However, estrogen administration did not affect vitamin C status in female plantaris or male lung, while resulting in significantly elevated vitamin C level in female lung. Tissue vitamin E status was unaffected by estrogen administration in either gender. Estrogen administration induced GSH loss in some tissues, indicating increased metabolic or oxidative stress and lowered growth rates and nutrient intakes particularly in male guinea pigs. However, tissue glycogen levels were not always affected by estrogen administration. Hence while, the effects of estrogen administration on tissue vitamin C status may in part be due to its effect on metabolism and nutrient intake, these factors cannot fully account for all the effects on tissue vitamin C status seen in this study. It is possible that estrogen administration has other tissue specific effects on vitamin C metabolism in guinea pigs

Low zinc status in guinea pigs and chicks has no effect on reassembly rate of brain microtubules

Zinc deficiency in guinea pigs and chicks results in peripheral neuropathy. Slowed reassembly of brain microtubules in zinc deficient rats has been reported, and such a defect might explain the neuropathy. To investigate this possibility, growing guinea pigs, chicks, and rats were fed a low zinc diet ad libitum (− Zn:AL), a control diet restricted (+ Zn:RF) to the intake of the − Zn:AL group, and the control diet ad libitum (+ Zn:AL). When the − Zn:AL guinea pigs and chicks exhibited neuropathy, at approximately 7 wk and 3 wk, respectively, a supernatant fraction of the brain was prepared and microtubule reassembly rates determined. Tubulin concentration and its sulfhydryl content were determined, as was the zinc content of the supernatant fraction. Similar measurements were made on rat brains taken after 3 wk, although the rats did not exhibit neurological signs. The reassembly rates of tubulin from the deficient guinea pigs and chicks were not decreased. That of the − Zn:AL rats was significantly less than that of the + Zn:AL group, but was not different from the + Zn:RF group. The tubulin sulfhydryl concentration was higher in deficient guinea pigs than in controls. There was no correlation between supernatant zinc concentration and the rate of reassembly. Because low zinc status had no effect in the guinea pig and chick, species susceptible to zinc deficiency neuropathy, it was concluded that the observed neuropathy is not the result of deranged properties of tubulin.

Regulation of blood acid base status in guinea pigs exposed to hypercapnia

1. 1. Arterial blood acid-base status of unanesthetized, unrestrained guinea pigs was studied during 6 hr of exposure to 4, 8, 10 and 14.5% CO 2. 2. 2. During exposure to 4% CO 2, blood pH was kept within the range of control values, despite significant increase of 5–8 mmHg in PaCO 2. 3. 3. Most of the changes in blood acid-base status occurred during the first 30–60 min of exposure to CO 2. and only minor changes were observed during the remaining exposure period (up to 6 hr). 4. 4. In-vivo CO 2 titration curves were not linear over the CO 2 range studied here. The slope of the in-vivo H +/PaCO 2 line became much more steep at PaCO 2 values higher than 65–75 mmHg. 5. 5. The apparent whole body buffer value ( β = − ΔHCO 3 −/ ΔpH), being 42.6 slykes after 1 hr for the 4–10% CO 2 range, changed to −18.1 slykes when calculated for 1 hr at the 10–14.5% CO 2 range. 6. 6. It is concluded that guinea pigs can regulate their blood pH better than rats, rabbits, dogs and men when exposed for short periods to CO 2 levels up to 10%. 7. 7. When exposed to higher levels (14.5%) of CO 2, they show a very limited capability for regulating their blood pH—much less than rats, rabbits and dogs.

Effect of Selenium Deficiency on Liver and Blood Glutathione Peroxidase Activity in Guinea Pigs

Male weanling guinea pigs were fed selenium-deficient and control diets for 10 weeks and the activity of glutathione peroxidase was studied in liver 105,000 × g supernatant and in blood using both 0.25 mm H2O2 and 1.5 mm cumene hydroperoxide as substrates. In control liver supernatant, the activity measured with H2O2 was about 20% of that measured with cumene hydroperoxide, indicating that only a small fraction of the total glutathione peroxidase present was selenium-dependent glutathione peroxidase (Se GSH-Px). Se GSH-Px decreased to 20% of control Se GSH-Px in livers of animals fed the selenium-deficient diet, but because it was such a small fraction of the total glutathione peroxidase activity, selenium deficiency did not affect total glutathione peroxidase activity in liver supernatant. In contrast to the liver results, blood glutathione peroxidase activities were higher when H2O2 was used as substrate than when cumene hydroperoxide was used. Gel filtration experiments suggested that this was due to interference with the assay by guinea pig hemoglobin which apparently caused oxidation of NADPH in the assay system. This oxidation was greater when H2O2 was used as substrate than when cumene hydroperoxide was employed. The presence of Se GSH-Px in red blood cells and its decrease in selenium deficiency were demonstrated by the gel filtration experiments. These results indicate that selenium is required by the guinea pig and that a biochemical deficiency state can be induced by dietary means. They also demonstrate the difficulties encountered in assessing selenium status in guinea pigs by measurement of glutathione peroxidase activity. Similar difficulties may be expected in other species.selenium glutathione peroxidase guinea pig

Reductions in aggression and dominance status in guinea pigs following bilateral lesions in the basolateral amygdala or lateral septum

Two studies assessing the effects of limbic lesions on aggression and dominance status in the guinea pig were performed. In Experiment 1 the dominant animal in each of 13 groups (dyads or triads) was selected to receive a bilateral lesion in the basolateral nuclei of the amygdala, while its sham or unoperated peers served as controls. In 6 animals the lesions were in the target area and all of these animals fell in their dominance hierarchies, most to the bottom. The other 7 animals suffered damage to areas proximal to, but not in, the amygdala, and they maintained their dominance status throughout the post-operative observation period. In Experiment 2 the dominant animal in each of 9 triads was selected to receive a bilateral lesion in the lateral septum, while its sham or unoperated peers served as controls. In 5 animals the lesions were in the lateral septum and all of these animals lost their alpha dominance status. One animal died post-operatively; in the remaining 3 animals the lesions were dorsal to the target area and these 3 animals maintained their dominance status throughout. Both types of lesions led to reductions of aggression and dominance status, for apparently different reasons. The reduction following the amygdaloid lesions appears to be a result of the animals' inability to adequately defend themselves, while the reduction following the septal lesions appears to stem from an increase in hyperreactivity. No recovery of function was observed in the amygdaloid animals; however, the septal animals displayed evidence of recovery from the effects of their lesions.

Stress response in chronic hypercapnia.

ARTICLESStress response in chronic hypercapniaKE Schaefer, N McCabe, and J WithersKE Schaefer, N McCabe, and J WithersPublished Online:01 Mar 1968https://doi.org/10.1152/ajplegacy.1968.214.3.543MoreSectionsPDF (1 MB)Download PDF ToolsExport citationAdd to favoritesGet permissionsTrack citations ShareShare onFacebookTwitterLinkedInWeChat Previous Back to Top Next Download PDF FiguresReferencesRelatedInformation Cited ByHypercapnia Regulates Gene Expression and Tissue Function20 November 2020 | Frontiers in Physiology, Vol. 11Dodecandisäure [MAK Value Documentation in German language, 2008]31 January 2012Toxicity of Carbon Dioxide: A Review19 July 2011 | Chemical Research in Toxicology, Vol. 24, No. 12Regulation of gene expression by carbon dioxide18 February 2011 | The Journal of Physiology, Vol. 589, No. 4Environmental Stress, Erythrocyte Dysfunctions, Inflammation, and the Metabolic Syndrome: Adaptations to CO 2 Increases?Journal of the CardioMetabolic Syndrome, Vol. 3, No. 1Long-term effects of the perinatal environment on respiratory controlRyan W. Bavis, and Gordon S. Mitchell1 April 2008 | Journal of Applied Physiology, Vol. 104, No. 4Gas Exchange in Acid‐Base Disturbances1 January 2011Carbon Dioxide NarcosisRegulation of blood acid base status in guinea pigs exposed to hypercapniaComparative Biochemistry and Physiology Part A: Physiology, Vol. 75, No. 1Energetics of mice in stable and unstable social conditions: Evidence of an air-borne factor affecting metabolismAnimal Behaviour, Vol. 28, No. 1Blood-gas properties and function in the fossorial mole rat under normal and hypoxic-hypercapnic atmospheric conditionsRespiration Physiology, Vol. 30, No. 1-2Metabolic Responses of a Fossorial Rodent (Spalax ehrenbergi) to Simulated Burrow ConditionsPhysiological Zoology, Vol. 50, No. 1Metabolic Aspects of Adaptation to Carbon DioxideVariations d’Activité de la Cortico surrénale et de l’Appareil hypothalamo-hypophysaire chez le Rat maintenu en Hypercapnie de longue DuréeBeiträge zur Pathologie, Vol. 149, No. 4The effects of chronic hypercapnia on blood phosphofructokinase activity and the adenine nucleotide systemRespiration Physiology, Vol. 16, No. 2Methemoglobin formation and red cell metabolism in guinea pigs during chronic hypercapniaRespiration Physiology, Vol. 13, No. 3RATE OF ACCLIMATIZATION TO CHRONIC HYPERCAPNIA IN MANCOMPARISON OF PHYSIOLOGICAL RESPONSES OF NORMAL MAN TO EXERCISE IN AIR AND IN ACUTE AND CHRONIC HYPERCAPNIADisplacement of oxygen dissociation curves and red cell cation exchange in chronic hypercapniaRespiration Physiology, Vol. 10, No. 3 More from this issue > Volume 214Issue 3March 1968Pages 543-548 Copyright & PermissionsCopyright © 1968 by American Physiological Societyhttps://doi.org/10.1152/ajplegacy.1968.214.3.543PubMed5638987History Published online 1 March 1968 Published in print 1 March 1968 Metrics