Social Status and Plasma-Testosterone-Titers in Male Guinea Pigs (Cavia aperes f. porcellus)

The relationship between social status and testosterone (T) titers was studied in male guinea pigs living in a) either one group of 12 males and 12 females for 14–20 months in a 7.86 m² enclosure or in b) five groups of 3 males and 2 females for four months in 3.00 m² enclosures. As described in the literature the social structure of the large group was mainly characterized by long-term male-female associations and spatial preferences whereas in the small groups the linear rank-order between the males was the most obvious element. In all groups the rank-position was positively correlated with the amount of courtship bouts displayed. Fighting occurred only in the large group and in one small group where a challenge to the alpha-position took place. Here the highest ranking males showed highest T-titers in their groups. In those four groups where no fighting occurred rank-position and amount of courtship behaviour displayed was uncorrelated to plasma-T-titers. Our findings suggest that endogenous levels of T only reflect the highest ranking males' social status when their social position is challenged. When dominance relations are resolved and stabilized a male's rank-position and its amount of courtship behaviour displayed appear independent of plasma-T-levels in guinea pigs.     

Cryptosporidium wrairi sp. n. from the Guinea Pig Cavia porcellus, with an Emendation of the Genus

SYNOPSIS. Cryptosporidium wrairi sp. n. is described from the laboratory guinea pig Cavia porcellus. The life cycle is given insofar as it is known. Two schizogonous generations are described; the 1st with 8 merozoites, the 2nd with 4 merozoites. The latter generation was previously referred to as the sporulated oocyst, but evidence is presented to show that it is a schizont. Micro- and macrogametogony are also described. No oocysts were found. Cross-transmission to mice, chickens, turkeys and rabbits was unsuccessful. The generic character of oocysts with 4 naked sporozoites is discarded and the presence of endogenous stages in the striated border of epithelial cells is used as the emended generic character. A listing of valid and non-valid species is given.     

Blood coagulation studies in guineapigs (Cavia porcellus)

Blood coagulation studies were performed on 45 healthy, adult guinea pigs. Additionally thrombelastograms of 30 animals were recorded. Guineapigs revealed short partial thromboplastin times and euglobulin lysis times, but long prothrombin times and thrombin times. Fibrinogen values were within the range of human normal values. Biphasic ADP-induced aggregation of platelets, as occurs in man, was found in 29% of the animals. Short r (reaction time until the beginning of clot formation) and k times (time from the beginning of clot formation until an amplitude of 20 mm) of their thrombelastograms indicate, that whole blood clotting is enhanced in guineapigs. Higher maximum amplitudes in this species suggest a stronger clot stability than in man.     

Genetic diversity and population structure of the Guinea pig (Cavia porcellus, Rodentia, Caviidae) in Colombia

The aim was to establish the genetic diversity and population structure of three guinea pig lines, from seven production zones located in Nari?o, southwest Colombia. A total of 384 individuals were genotyped with six microsatellite markers. The measurement of intrapopulation diversity revealed allelic richness ranging from 3.0 to 6.56, and observed heterozygosity (Ho) from 0.33 to 0.60, with a deficit in heterozygous individuals. Although statistically significant (p < 0.05), genetic differentiation between population pairs was found to be low. Genetic distance, as well as clustering of guinea-pig lines and populations, coincided with the historical and geographical distribution of the populations. Likewise, high genetic identity between improved and native lines was established. An analysis of group probabilistic assignment revealed that each line should not be considered as a genetically homogeneous group. The findings corroborate the absorption of native genetic material into the improved line introduced into Colombia from Peru. It is necessary to establish conservation programs for native-line individuals in Nari?o, and control genealogical and production records in order to reduce the inbreeding values in the populations.     

Immunoglobulin genomics in the guinea pig (Cavia porcellus)

In science, the guinea pig is known as one of the gold standards for modeling human disease. It is especially important as a molecular and cellular biology model for studying the human immune system, as its immunological genes are more similar to human genes than are those of mice. The utility of the guinea pig as a model organism can be further enhanced by further characterization of the genes encoding components of the immune system. Here, we report the genomic organization of the guinea pig immunoglobulin (Ig) heavy and light chain genes. The guinea pig IgH locus is located in genomic scaffolds 54 and 75, and spans approximately 6,480 kb. 507 V(H) segments (94 potentially functional genes and 413 pseudogenes), 41 D(H) segments, six J(H) segments, four constant region genes (μ, γ, ε, and α), and one reverse δ remnant fragment were identified within the two scaffolds. Many V(H) pseudogenes were found within the guinea pig, and likely constituted a potential donor pool for gene conversion during evolution. The Igκ locus mapped to a 4,029 kb region of scaffold 37 and 24 is composed of 349 V(κ) (111 potentially functional genes and 238 pseudogenes), three J(κ) and one C(κ) genes. The Igλ locus spans 1,642 kb in scaffold 4 and consists of 142 V(λ) (58 potentially functional genes and 84 pseudogenes) and 11 J(λ) -C(λ) clusters. Phylogenetic analysis suggested the guinea pig's large germline V(H) gene segments appear to form limited gene families. Therefore, this species may generate antibody diversity via a gene conversion-like mechanism associated with its pseudogene reserves.     

Evaluating the Clinical and Physiological Effects of Long Term Ultraviolet B Radiation on Guinea Pigs (Cavia porcellus)

Vitamin D is an important hormone in vertebrates. Most animals acquire this hormone through their diet, secondary to exposure to ultraviolet B (UVB) radiation, or a combination thereof. The objectives for this research were to evaluate the clinical and physiologic effects of artificial UVB light supplementation on guinea pigs (Cavia porcellus) and to evaluate the long-term safety of artificial UVB light supplementation over the course of six months. Twelve juvenile acromelanic Hartley guinea pigs were randomly assigned to one of two treatment groups: Group A was exposed to 12 hours of artificial UVB radiation daily and Group B received only ambient fluorescent light for 12 hours daily. Animals in both groups were offered the same diet and housed under the same conditions. Blood samples were collected every three weeks to measure blood chemistry values, parathyroid hormone, ionized calcium, and serum 25-hydroxyvitamin D₃ (25-OHD₃) levels. Serial ophthalmologic examinations, computed tomography scans, and dual energy x-ray absorptiometry scans were performed during the course of the study. At the end of the study the animals were euthanized and necropsied. Mean ± SD serum 25-OHD₃ concentrations differed significantly in the guinea pigs (p<0.0001) between the UVB supplementation group (101.49±21.81 nmol/L) and the control group (36.33±24.42 nmol/L). An increased corneal thickness in both eyes was also found in the UVB supplementation compared to the control group (right eye [OD]: p<0.0001; left eye [OS]: p<0.0001). There were no apparent negative clinical or pathologic side effects noted between the groups. This study found that exposing guinea pigs to UVB radiation long term significantly increased their circulating serum 25-OHD₃ levels, and that this increase was sustainable over time. Providing guinea pigs exposure to UVB may be an important husbandry consideration that is not currently recommended.     

利用染色体涂染方法建立人和白眉长臂猿(Hylobates hoolock)的比较染色体图谱

除人Y染色体外,本文采用生物素标记的人全部整条染色体特异探针与白眉长臂猿(Hylobates hoolock)有丝分裂中期分裂相进行染色体原位杂交即染色体涂染法以研究人和白眉长臂猿染色体之间的同源性。在白眉长臂猿18对常染色体上检测出了与人22对常染色体同源的59对染色体片段,确定了人和白眉长臂猿之间的精度较高的染色体连锁群。结果表明:自人与白眉长臂猿的祖先分歧以来,大量的染色体间重排(至少发生了39次易位)和染色体内的重排导致了二者核型的差异。根据杂交结果绘制了首份人和白眉长臂猿比较染色体图谱,并结合已有的人和白掌长臂猿(Hylobates lar)(2n=44)和合趾长臂猿(Hylobates syndactylus)(2n=50)的比较染色体图谱对长臂猿属的染色体进化作了初步的探讨。     

Control of the estrous cycle in guinea-pig (Cavia porcellus)

The aim of this work was to look for a simple method to obtain synchronized ovulation in guinea pigs under farming conditions while respecting animal welfare. The luteolytic activity of three different prostaglandins F2alpha (PGF2α) analogs (D-cloprostenol, D,L-cloprostenol and luprostiol) and a daily treatment with oral progestagen (altrenogest) was tested successively at different stages of the estrous cycle on the same group of females during a period of 8 mo. The estrous cycle length was not modified by the administration of PGF2α analogs, whatever the stage of the estrous cycle when the treatment was initiated. Our results led us to reject the use of PGF2α analog to induce practical synchronization of the estrus in this species. In females (n = 29), given 15 days with altrenogest (0.1 mL po once a day), ovulation occurred 4.43 ± 0.13 days after the end of the treatment. Altrenogest treatment was followed by mating. No negative impacts of the treatment on the pregnancy rates, delivery rates and litter sizes were observed. This standard method of guinea-pig estrus synchronization is less stressful for the animals compared to techniques using progesterone tubing.     

Urethral catheterization of the male guinea pig (Cavia porcellus)

Urethral catheterization of the male guinea pig has potential diagnostic, therapeutic, and research applications. Urethral catheter placement requires an understanding of the unique anatomy of the lower urinary tract in order to avoid iatrogenic injury to the urethra and to ensure successful catheterization.     

Urethral catheterization in the female guinea pig (Cavia porcellus)

Urethral catheterization of the female guinea pig has potential diagnostic, therapeutic and research applications. Urethral catheter placement in the female guinea pig is relatively easy to carry out and has fewer potential complications than does catheter placement in male guinea pigs.     

A comparative study of hepatic and epidermal histidase in the guinea-pig (Cavia porcellus)

Histidine ammonia lyase was purified to homogeneity from guinea-pig liver and epidermis. Both enzymes had similar molecular weights, subunit composition and pH optima. Km values for the two were similar at pH 9.2 but different at pH 7.0. Both enzymes were stimulated by low thiol concentrations and inhibited at higher concentrations, but to different extents. Antibody to the hepatic enzyme showed complete identity against hepatic enzyme but incomplete identity against epidermal enzyme.     

Comparison of fibre digestion and digesta retention time between nutrias (Myocaster coypus) and guinea-pigs (Cavia porcellus)

• 1.1. Digestibilities of feed, and transit and retention time of fluid and particle digesta marker measured in nutrias (Myocaster coypus) and guinea-pigs (Cavia porcellus) fed on a diet containing 50% alfalfa.
• 2.2. The digestibility of fibre was higher in the nutria, along with the longer retention time of digesta.
• 3.3. The liquid and particle marker were similarly excreted, suggesting no separation mechanism in the gastrointestinal tract of both the animals.
• 4.4. The apparent digestibility of protein in the nutria was superior to the guinea-pig and other small hindgut fermenters, suggesting that the contribution of coprophagy on protein nutrition of nutrias is significant.

     

Olfactory Individual Recognition of Mothers by Young Guinea-Pigs (Cavia porcellus)

In mammals, olfactory cues play a major role in individual recognition and urine is one source of potentially individual‐specific olfactory cues. We studied how soon young of the extremely precocial domestic guinea‐pig (Cavia porcellus) establish specific preferences for maternal urine smell by offering 5–30‐d‐old young a simultaneous choice between a urine sample of the mother and urine from an unfamiliar unrelated lactating female. Young showed increasing preference for the smell of maternal urine from day 5 of life onwards. On day 10 of life, they discriminated between maternal urine and that of other lactating females when these were unfamiliar and related, unfamiliar and unrelated or familiar unrelated, but not when the urine of the other female came from a familiar and related lactating animal. The last result is based on fewer litters and, therefore has to be considered as preliminary. As our results are based on spontaneous preferences for just one source of olfactory cues, discrimination of live animals is likely to be even better than demonstrated here. Learning or phenotype matching of individual specific cues enable these precocial young to form a specific bond with their mother soon after birth.     

True pregnancy toxemia (preeclampsia) in the guinea pig (Cavia porcellus)

In this study, normal nonpregnant, normal full-term pregnant, fasting ketotic and spontaneous pregnancy toxemic guinea pigs were compared to define the mechanism of this disease. In addition to conventional clinical, laboratory and pathologic studies, arterial blood pressure (thoracic and abdominal aortic) measurements and angiography were used. The results showed that in spontaneous cases of pregnancy toxemia, there is an aortic compression just caudal to the renal arteries. This compression reduced the aortic diameter by 22% of prerenal level as compared to 10% for fasting ketotic and normal pregnant guinea pigs. The aortic compression also resulted in a 30% postcompression reduction in blood pressure. No pressure differences were seen in the other groups. The postulated etiology for true toxemia of pregnancy in guinea pigs is, therefore, similar to that of man where aortic compression produces uterine ischemia and the resultant syndrome.     

The behavioral endocrinology of domestication: A comparison between the domestic guinea pig (Cavia aperea f. porcellus) and its wild ancestor, the cavy (Cavia aperea)

In this study spontaneous behavior and endocrine parameters were compared between the domestic guinea pig (Cavia aperea f. porcellus) and its wild ancestor, the cavy (Cavia aperea), to elucidate the process of domestication in this species. In 120 h of observation time the behavior of five groups of wild and seven groups of domestic guinea pigs, each consisting of one adult male and two adult females, was analyzed quantitatively. To assess the activities of the pituitary-adrenocortical (PAC), the pituitary-gonadal (PG), and the sympathetic-adrenomedullary (SAM) systems, serum cortisol, testosterone, epinephrine, and norepinephrine concentrations, as well as adrenal tyrosine hydroxylase activities, were determined in males of both forms. The following significant differences between wild cavies and domestic guinea pigs were found: the domesticated animals displayed less aggressive but more sociopositive and more male courtship behavior than their wild ancestors. In addition, they were distinctly less attentive to their physical environment than the wild cavies. The basal activity of the SAM system, as well as the reactivity of the SAM and the PAC systems, was distinctly reduced in the domesticated animals. In contrast, the basal activity of the PAC system did not differ between both forms. The activity of the PG system was significantly higher in males of the domestic guinea pig than in male wild cavies. Thus, in guinea pigs the process of domestication has led to typical behavioral traits-reduced aggressiveness, increased social tolerance-which have also been found in comparisons between wild and domestic forms of other species. The decreased reactivity of the organism's stress axes can be regarded as a physiological mechanism which helps domesticated animals to adjust to man-made housing conditions.     

Age-related changes in haematology and serum chemistry of Weiser-Maples guineapigs (Cavia porcellus)

Age-related changes in haematology and serum chemistry values were examined in male and female Weiser-Maples guineapigs (Cavia porcellus). Haematological changes that significantly (P<0.01) correlated with ageing were increased white blood cell and neutrophil counts in both sexes, decreased lymphocyte counts in both sexes, decreased reticulocyte and platelet counts in males, and decreased basophil counts in females. For serum chemistry, increases in total protein, triglycerides, blood urea nitrogen and creatinine were seen in both sexes, along with increases in total cholesterol in males and sodium in females. Decreased alkaline phosphatase in both sexes and decreased chloride in males were significantly (P<0.01) associated with age. These age-related changes are compared with the published literature.