Article

Impact of pelleted diets with different mineral compositions on the crown size of mandibular cheek teeth and mandibular relative density in degus (Octodon degus)

Authors:
  • Jekl & Hauptman Veterinary Clinic , Brno, Czech Republic & University of Veterinary Sciences Brno Department of Pharmacology and Pharmacy Faculty of Veterinary Medicine
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Abstract

The impact of pelleted diets with different mineral compositions on the crown size of the mandibular cheek teeth, as well as the mandibular bone and cheek teeth density, in degus (Octodon degus) was investigated. A total of 28 animals were randomly divided into four groups and fed different calcium or phosphorous dietary content, in the presence or absence of UV light, for 14 months. Dental radiographs and CT images of the head were taken, and the crown size of premolar and molar teeth was recorded. Apical and coronal crown elongation of all cheek teeth and significantly smaller relative cheek teeth and mandibular densities were recorded in degus fed a high-phosphorus diet with an improper calcium:phosphorus ratio. A diet with a calcium:phosphorus ratio of 1:1 was also responsible for the rapid development of dental disease with subsequent severe health impairment.

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... The use of degus (Octodon degus, Octodontidae, Rodentia), hystricomorphic medium-sized diurnal rodents, as a laboratory subject has grown over the last few decades due to their unique biological features, especially in the research of anatomy and physiology, aging, diabetes mellitus, vision, behavior, and social interactions (13)(14)(15)(16). Studies published in privately kept degus have shown a very high incidence of spontaneous dental disease, which was characterized by apical and coronal clinical crown elongation, tooth sharp spike formation, and orthodontic tooth movement within the jaw (17). Experimental studies in degus showed that chronic high dietary phosphorus intake with adequate calcium and vitamin D intake had deteriorative effects on degus dentition and cause enamel hypoplasia and mandibular osteoporosis (18,19). ...
... Dental radiographs of the left mandible confirmed, in particular, a reserve crown elongation of all teeth in both the coronal and apical directions. Significant elongation of the mandibular incisors, 4th premolar, and all molar teeth were recorded in group B (17). ...
... As the 4th premolar and molar teeth in degus erupt continuously, the effect of mineral metabolism can affect the teeth in any age. The previous articles showed that teeth of a degu, a hystricomorph rodent with continuously erupting incisors, premolar teeth, and molar teeth, under a high-phosphorus diet elongated coronally and apically had impaired enamel and dentin apposition, and these degus had also decalcified jaws (17)(18)(19)21). The present study showed that degus chronically fed by a high-phosphorus diet had significantly thinner ventral mandibular cortical thickness when compared with degus fed by normal diet. ...
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Article
Adverse effects of high dietary phosphorus on bone health have been observed in both animal and human studies. The aim of the investigation was to examine chronic effect of high phosphorus diet on the apical mandibular cortical thickness and volume in a hystricomorph rodent (Octodon degus) using micro-computed tomography. Male degus were randomly divided into two groups fed by different mineral content from the age of 12 weeks till the age of 17 months. The micro-CT scanning, and wall thickness analysis was applied on region of the mandible exactly under the apices of the 4th premolar tooth, first and second molar tooth in 2 animals from each group. General overview and mapping of the ventral mandibular bone thickness revealed pronounced bony mandibular protrusions in all the animals fed a high-phosphorus diet with obvious bone thinning apically to the 4th premolar and first and second molar teeth apices. Mandibular bone volume and thickness located apically to the premolar and molars were statistically significantly smaller/thinner in group fed by high phosphorus diet. The thinnest bone measured 0.004 mm, where the 4th premolar tooth almost perforated mandibular cortex. The influence of different environmental, infectious, or metabolic factors on the growing tooth, alveolar bone formation, and bone pathologies must be done experimentally on growing animals. In contrast, degus have continuously growing dentition, and the effect of any of the above listed factors can be studied in this animal model at any age and for longer time periods.
... In contrast, pet rabbits frequently consume a diet consisting largely of concentrate foods (monocomponent nuggets or mixed mueslis) with no or limited roughage intake (Harcourt-Brown 1996, Mullan & Main 2006, Schepers et al. 2009, PDSA 2011. Whilst inadequate or incorrect diet is widely expected to cause dental disease, several theories describing the possible aetiopathogeneses have been proposed including a lack of attrition (Crossley 2003, Crossley 2005) and calcium/phosphorus imbalance (Harcourt-Brown 1996, Jekl et al. 2011a,b, Gumpenberger et al. 2012. ...
... A previous study suggested that selective feeding of muesli components led to a low calcium diet and subsequent metabolic bone disease that leads to dental disease (Harcourt-Brown 1996). Dental disease has also been induced in degus that were fed a diet with normal calcium content through the feeding of a high phosphorus diet (Jekl et al. 2011a,b, Gumpenberger et al. 2012). However, whilst selective feeding did occur in the MO and MH groups [as reported in ], the amounts of calcium and phosphorus consumed (Table 3) were within the guidelines of 0·4-1% for calcium (Kamphues 1991, Harcourt-Brown 1996, Norris et al. 2001, Lowe 2010) and 0·3-0·7% for phosphorus (Mateos and De Blas 2010) and reversed calcium: phosphorus ratios were not present. ...
... The current study adds support to the hypothesis that low intake of forage, but not calcium and phosphorus imbalance, is implicated in the development of dental disease. However, the presence of multiple nutritional factors that contribute to the development of dental disease either alone or in contribution with other factors is also possible (Crossley 2005, Jekl et al. 2011a, Müller et al. 2014. The presence of cheek tooth elongation and curvature in rabbits in both the groups fed muesli indicates that muesli-based diets are not suitable for pet rabbits whether or not they are given with hay. ...
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To assess the impact of four rabbit diets (hay only; extruded diet with hay; muesli with hay; muesli only) on length and curvature of cheek teeth and eruption and attrition rates of incisors. Thirty-two Dutch rabbits, randomly divided into four diet groups, had length and saggital plane curvature of the first cheek teeth measured radiographically at 1, 9 and 17 months. Eruption/attrition of the left upper incisor was directly measured at weeks 30, 32 and 35. Eruption rates matched attrition rates in all groups, but were higher in the hay only group than in both groups fed muesli. By month 9, a greater degree of tooth curvature was present in rabbits fed muesli only than in those fed hay only and extruded diet with hay. After 17 months, rabbits fed muesli only and muesli with hay had longer lower first cheek teeth and larger interdental spaces between the first two molars than rabbits fed extruded diet and hay and hay only. Three rabbits fed muesli only developed evidence of dental disease. Presence of increased tooth length, curvature and interdental spaces indicated early dental pathology in rabbits fed muesli. Muesli diets cannot be recommended for pet rabbits. © 2015 British Small Animal Veterinary Association.
... experimentally (Jekl et al. 2011a,c, Gumpenberger et al. 2012. Degus in these studies were fed high-phosphorus diets with dietary calcium to phosphorus ratio 1:1 for 14 months. ...
... Southard et al. (2000) showed that in experimental osteoporotic female rabbits, mandibular bone mineral density decreases in relation to spinal density. On the basis of experimental studies in rodents (Jekl et al. 2011a) early and mild, and occasionally, even more severe changes may be detectable only by advanced imaging methods and/or histopathological bone examination rather than by radiography. ...
... The relationship between systemic disease/systemic stress and oral bone loss/germinative tooth tissue pathology is a complex problem. Deterioration of tooth quality and abnormalities in tooth eruption (irregular hyperplasia of dentin arrangement, enamel loss, horizontal ridges on incisors, etc.) are present because of pathological changes of tooth germinative tissue or periodontal attachment (Fig 4), which could be caused by metabolic bone disease (Harcourt-Brown 2009, Jekl et al. 2011a, trauma, inflammation, vascular damage or ageing changes (Wiggs & Lobprise 1997b). In degus, metabolic bone disease, apart from alveolar bone changes (osteoporosis), causes significant changes in dentin and enamel with subsequent dental disease development and/or general dental disease aggravation (Jekl et al. 2011c). ...
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Dental disease is considered as one of the, if not, the most common disorders seen in pet rabbits. This article provides a review of the scientific literature and an overview of the peculiarities of calcium homeostasis in the rabbit in an attempt to draw together current thinking on the cause of dental disease. A complete understanding of the aetiology and pathophysiology of rabbit dental disease is necessary for the veterinary practitioner to establish a proper therapeutic plan, prognosis and ultimately prevention of this common cause of morbidity and mortality in pet rabbits.
... Degus (Octodon degus, Octodontidae, Rodentia) are diurnal social rodents, which are commonly used in a research of nutrition, diabetes, brain and behavior [25,26]. Recent studies showed that degus had a very high incidence of spontaneous dental disease, which is characterized by apical and coronal elongation of all teeth with subsequent development of incisor, premolar and molar malocclusion [27,28]. The experimental study in degus showed that high phosphorus diet with adequate calcium and vitamin D intake had deteriorative effects on degus dentition and cause mandibular osteoporosis [27]. ...
... Recent studies showed that degus had a very high incidence of spontaneous dental disease, which is characterized by apical and coronal elongation of all teeth with subsequent development of incisor, premolar and molar malocclusion [27,28]. The experimental study in degus showed that high phosphorus diet with adequate calcium and vitamin D intake had deteriorative effects on degus dentition and cause mandibular osteoporosis [27]. ...
... The results of Shah et al. [47] and Kemi et al. [21] revealed that increase in bone resorption is also seen in cases of chronic consumption of a diet in which there is either a suboptimal concentration of calcium or adverse Ca:P ratio when the calcium level is adequate. Similar results were recorded by Jekl et al. [27], where significantly lower mandibular bone and teeth densities were recorded in the same degus fed by high phosphorus diet and improper Ca:P ratio when comparing with control groups. Bone and dentin are mineralized tissues that closely resemble each other in composition and mechanism of formation [48,49]. ...
... Some authors have raised questions regarding a possible link between dental disease and a lack of UVB exposure in pet rabbits 8,67 and degus. 68,69 Neither of these studies concluded there was a causative link, [67][68][69][70] and this question is still under debate. ...
... Some authors have raised questions regarding a possible link between dental disease and a lack of UVB exposure in pet rabbits 8,67 and degus. 68,69 Neither of these studies concluded there was a causative link, [67][68][69][70] and this question is still under debate. ...
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Many animals under human care are kept indoors to prevent infectious diseases vectored by wildlife, facilitate environment control, or due to the lifestyle of their owners. However, ultraviolet radiation has documented effects on animal vision, vitamin synthesis, immunity, behavior, psychogenic disorders and on their environment. Ultraviolet-emitting lights are commercially available and the documentation of their effect on indoor-housed animals is increasing. This article reviews published information about ultraviolet effects in vertebrate animals from veterinary and ethological perspectives, and techniques used to assess ultraviolet exposure across animal taxa.
... Dental disease is one of the most common diseases in guinea pigs and degus. 15,[60][61][62] These strictly herbivorous rodents have complete hypsodont aradicular/elodont dentition. Most animals with dental disease are presented for weight loss, reduced food intake or anorexia, and drooling. ...
... Degus are also commonly presented for dyspnea associated with elodontoma formation or due to cheek teeth elongation in the nasal cavity. 20,60 Pathophysiology of the dental disease is associated with less abrasive properties of the diet, alteration of the chewing pattern, reduction of the chewing duration, and mineral dietary imbalances. It was found that guinea pig teeth can adapt to the diet with different abrasiveness and that the rate of eruption and attrition changes. ...
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The number of exotic companion pet rodents seen in veterinary practices is growing very rapidly. According to the American Veterinary Medical Association's surveys, more than 2,093,000 pet rodents were kept in US households in 2007 and in 2012 it was more than 2,349,000 animals. This article summarizes the most important evidence-based knowledge in exotic pet rodents (diagnostics of the hyperadrenocorticism in guinea pigs, pituitary tumors in rats, urolithiasis in guinea pigs, use of itopride as prokinetics, use of deslorelin acetate in rodents, cause of dental disease, and prevention of mammary gland tumors in rats).
... 5 CT imaging revealed a higher sensitivity and accuracy for diagnosis of dental disease in rabbits than radiography 27 and can be used for quantitative measurement of bone mineral density. 10 When CT is not easy accessible or too expensive, conventional radiography appears to be a good method to diagnose apical elongation but cannot predict the extent of bone resorption for the animal. ...
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Article
Degus (Octodon degus) are prone to develop dental disease with deleterious health effects. The two studies reported here aimed to determine the prevalence of dental disorders in degus and to identify and evaluate diagnostic tools for determination of prognosis of these disorders. In study A, health data from 225 degus at AAP, Rescue Center for Exotic Animals in the Netherlands, were collated and the prevalence of dental disorders and differences in sex and age at clinical onset of symptoms associated with dental disorders were described. The prevalence was 34.7 per cent and higher (P<0.01) in males than in females. The occurrence of cheek teeth malocclusion was highly positively (P<0.0001) correlated to mortality. In study B, 36 skulls were examined by macroscopic evaluation, radiography and histology. Additionally, the calcium:phosphorus (Ca:P) of mandibular bone in degus with and without dental disorders were determined. There was no significant (P=0.10) difference in Ca:P between the two groups. Quantifying mandibular apical cheek teeth elongation via macroscopic evaluation was highly correlated (P<0.01) to the results obtained via radiography. Examination for apical elongation by palpation and diagnostic imaging should be included in routine health monitoring of degus. Apical elongation appeared to develop before coronal elongation and when cheek teeth malocclusion occurred, prognosis for recovery of dental disease was poor.
... In degus, a resulting Ca:P dietary imbalance by feeding a high phosphorus and normal calcium (1:1) diet has been shown to induce dental disease of all teeth (incisor depigmentation, enamel hypoplasia, disruption in dentin and cementum formation, and apical and coronal cheek teeth elongation) within 6 months, in addition to significantly reduction in mandibular bone density. 11 Tooth elongation affecting the reserve and/or the clinical crown is the cause for most clinical signs and symptoms associated with dental disease in chinchillas and degus. Apical cheek tooth elongation can result in pain associated with apical tooth pressure onto the nerve endings, growth through the periosteum, and intrusive pressure of the tooth to the germinal tissue associated with ischemia. ...
Dental disease is among the most common causes for chinchillas and degus to present to veterinarians. Most animals with dental disease present with weight loss, reduced food intake/anorexia, and drooling. Degus commonly present with dyspnea. Dental disease has been primarily referred to as elongation and malocclusion of the cheek teeth. Periodontal disease, caries, and tooth resorption are common diseases in chinchillas, but are missed frequently during routine intraoral examination, even performed under general anesthesia. A diagnostic evaluation, including endoscopy-guided intraoral examination and diagnostic imaging of the skull, is necessary to detect oral disorders and to perform the appropriate therapy.
... Hereditary malocclusion has been reported in rabbits 17 and in guinea pigs, 18 but no clinical cases of congenital dental abnormalities are reported in degus. Dental disease is reported to be associated with the abrasiveness of dietary material, and/or with mineral imbalances, which have been confirmed in degus, 19 rabbits, 20 and guinea pigs. 21 In this case, the cause of dental disease could have been associated with dietary mineral imbalance as a hypocalcemia and improper plasma calcium to phosphorus ratio was detected. ...
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An adult 2-year-old 173 g intact male degu (Octodon degus) was presented to the authors’ clinic with a 2-week history of reduced food intake, weight loss, epiphora, and dyspnea. Physical examination revealed lethargy, cachexia, bilateral serous ocular discharge, dehydration, inspiratory dyspnea, and severe dental disease. Diagnostic investigation showed extensive apical elongation of premolars causing partial nasal cavity obstruction by masses of increased opacity, and loss of conchal detail. The animal was euthanized due to general poor condition and the severity of disease. Postmortem micro computed tomography showed marked reserve crown elongation of all premolars and molars. All cheek teeth were abnormally curved and had widened interdental spaces. The apex of the maxillary left premolar nearly penetrated the left nasal bone. Both maxillary premolars penetrated into the nasal cavity and caused complete left and partial right nasal cavity obstruction. Apices of all premolars were dysplastic.
... Dietary mineral imbalances, or lack of exposure to UVB, may lead to metabolic bone disease, which may impair occlusion due to osteodystrophy of the supporting bone and dental tissue malformation (Harcourt‐Brown, '95). Experimentally , minerally imbalanced diets led to cheek tooth elongation and enamel hypoplasia in degus (Octodon degus) (Jekl et al., 2011a,b). The other major dietary factor considered responsible for dental abnormalities are easily digestible (i.e., low‐fiber) diets that limit the absolute food intake, because energetic requirements are met by small amounts of such diets, leading to insufficient chewing activity and hence insufficient attrition (Wolf and Kamphues, &apos;96; Crossley, 2003; Meredith, 2007; Harkness et al., 2010; Lord, 2011). ...
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Chapter
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The effect of diet quality on basal metabolic rate (BMR) over time was studied in female Octodon degus. Degus fed on a low-quality diet maintained a constant BMR over time, while those fed on a high-quality diet showed all increased BMR after 30 days. After 120 days of dietary acclimation, individuals fed on a high-quality diet exhibited comparatively higher BMRs. Thus, we hypothesize that when environmental food quality is high, degus are able to increase their BMR quickly, allowing high rates of biosynthesis.
Article
Five captive adult female degus (Octodon degus) were offered leaves and twigs to eat from three woody (Adesmia bedwellii,Porlieria chilensisandProustia pungens) and two suffruticose (Baccharis paniculataandChenopodium petiolase) shrubs that provide cover in their natural habitat. The degus discriminated among the plant species, consuming lower amounts ofP. chilensis. Daily body mass losses of degus were significantly higher when they were fed uponP. pungensandP. chilensis. The nutritional value of plants, concomitant with degu nutritional requirements, may explain changes in shrub cover previously found to follow removal of degus from experimental plots.
Article
The effect of diet quality on basal metabolic rate (BMR) over time was studied in female Octodon degus. Degus fed on a low-quality diet maintained a constant BMR over time, while those fed on a high-quality diet showed an increased BMR after 30 days. After 120 days of dietary acclimation, individuals fed on a high-quality diet exhibited comparatively higher BMRs. Thus, we hypothesize that when environmental food quality is high, degus are able to increase their BMR quickly, allowing high rates of biosynthesis.
Article
Dental disease is one of the most common reasons for pet rabbits to need veterinary treatment. The continual eruption and growth of the teeth predispose rabbits to dental problems. Any abnormality in the shape, position, or structure of the teeth interferes with normal wear and can lead to malocclusion and crowns that are no longer functional, and may grow into surrounding soft tissue causing pain and eating or grooming difficulties. Root elongation is a feature of dental disease in rabbits and can lead to a number of clinical problems such as epiphora, dacrocystitis, or abscesses. Repeated examination of rabbits with dental problems alongside skull radiography and visual examination of prepared skulls from affected cases has shown that the majority of rabbits with dental problems are suffering from progressive changes in the shape, structure, and position of the teeth. The nature of the abnormal dental changes suggests that underlying metabolic bone disease is a possible cause. This progressive syndrome of acquired dental disease can be staged. This article describes the clinical and pathological features of each stage of progressive syndrome of acquired dental disease and provides recommendations for the treatment of cheek teeth malocclusion.
Article
Degus are commonly used as laboratory animals; however, over the past few years, they have become increasingly popular as pets. Objectives: The aim of this article was to present disease prevalence in 300 pet degus divided in two age groups (under and above two years). Medical records of degus (Octodon degus), which were presented to the author's clinic in the period from January 2007 to December 2009, were reviewed. The most common diseases in degus were (1) acquired dental disease (60·0%) with significantly higher prevalence in older animals (P<0.001), (2) skin alopecia due to fur chewing (13·33%) and (3) lens cataracts (13·33%). Other common disorders included traumatic injuries to soft tissues (bite wounds and tail slip), traumatic fractures and dietary diarrhoea. Reproductive disorders were most commonly associated with dystocia and pathological changes in the post-natal period. Only 38 degus in a total of 300 animals were healthy. This is the first study to describe the disease prevalence in two age groups of pet degus. The majority of diseases were caused by improper diet, self-mutilation and improper handling; as such client education is necessary to avoid such a high disease prevalence.
Article
Renal dysplasia is a hereditary disease characterized by abnormal differentiation of renal tissue. The ultrasonographic appearance of dysplastic canine kidneys has been reported in the late stage of the disease where inflammatory and degenerative changes are already present and the dogs are in chronic renal failure. In this study, we describe the ultrasonographic appearance of the kidneys of five related Cairn Terriers affected with renal dysplasia before the onset of clinical or laboratory evidence of renal failure. Common findings included poor corticomedullary definition and multifocal hyperechoic speckles in the renal medulla, or a diffusely hyperechoic medulla. Severity of ultrasonographic changes was related to the severity of histopathologic findings. The ability to detect dysplastic changes before clinical signs develop makes ultrasound a potentially useful screening method for canine renal dysplasia.
Article
Animal models of atherosclerosis are essential to elucidate disease mechanisms and develop new therapies. Each model features advantages and disadvantages in exemplifying the pathophysiology of human atherosclerosis. Diet-induced development of atherosclerosis in Octodon degus (degu) was examined to demonstrate the potential of the degu as a model of human atherosclerosis. Degus were fed for 16 weeks with either normal chow or chow containing 0.25% cholesterol and 6% palm oil to induce atherosclerosis. The lipid compositions of plasma lipoproteins and aortas were determined. Locations of aortic lesions were mapped by imaging of fluorescently stained aortic lesions. Lesion morphology in the brachiocephalic artery was detected by histological staining. Total plasma cholesterol in chow-fed degus was distributed approximately 60% in HDL, 30% in LDL and less than 10% in VLDL. Cholesterol-fed degus exhibited 4- to 5-fold increases in total plasma cholesterol, principally in the VLDL and LDL fractions. Cholesteryl ester transfer protein activity of similar magnitude to that in human plasma was detected in chow-fed degu plasma. Cholesterol-fed degus developed cholesteryl ester-rich atherosclerotic lesions throughout the aorta. Histological examination of lesions in the brachiocephalic artery showed well-formed, foam cell-rich lesions populated with inflammatory cells. It is also noteworthy that all the degus in this study exhibited hyperglycemia. These results demonstrate that degus have a human-like lipoprotein metabolism and develop extensive atherosclerosis with cholesterol feeding in the presence of hyperglycemia. These features, combined with the manageable size and handling characteristics, point to the potential of the degu as a useful model for atherosclerosis research.
Article
Octodon degus (degu), a biparental species with precocious offspring is a potential model for the study of social attachment and related affective disorders such as depression. This study investigates the nature of the social bond between young degus and their mothers with a special emphasis on infant-mother recognition. We tested young degus in a potentiation paradigm to determine if social contact, particularly with the mother, can modulate an infant's vocal response to isolation. One week later, animals were presented with a choice between their mother and an unfamiliar female or a sample of familiar and unfamiliar nesting materials. Subsequently, the ability of whole litters to discriminate between their mother and unfamiliar females was tested. We observed that infant degus alter their isolation response after brief social contact. Degu infants readily distinguish between familiar and unfamiliar nesting materials but fail to differentiate between their mother and unfamiliar females in an identical setting. Nevertheless, entire litters show a preference for their mothers when tested similarly in a group, demonstrating a perhaps socially facilitated ability to recognize the biological mother at an early age.
Octodon degus are herbivorous rodents that are adapted anatomically and behaviorally to utilize a fibrous diet with moderate-to-low levels of nonstructural carbohydrate. Captive degus should consume foods containing nutrients comparable to those consumed by free-ranging animals. The species is highly social, demonstrating a broad array of communication methods that make them appealing as a companion animal species. Controlled research studies with degus have produced a wealth of information that facilitates the care of this species in captivity.
Article
6 litters of Octodon degus were studied from birth to 10 days of age. Newly-born degus (mean weight 14.6 g) had open eyes, upper and lower pigment, fur, and teeth. Within 3-4 hours of birth they were able to walk supporting their full weight, right themselves rapidly, sit upright on their haunches, or rear upright with support, and vocalize. By the 1st or 2nd day, the young animals displayed functional grooming (face washing, hind-paw scratching, rapid head-shake). Solid food was ingested from day 6, although newborns chewed wood chips and 3-day olds gnawed dried faeces. Young degus were tested daily in an open field apparatus and showed increased activity and exploration, with repeated testing while decreasing distress vocalization after the 4th or 5th day. Degus are proposed for the study of developmental topics since their degree of development at birth allows for immediate testing. The degus studied here seem to be more fully developed at birth than those studied in Britain.
Article
The purpose of this research was to study the effect of corticosteroid-induced osteoporosis on orthodontic tooth movement and relapse. Sixteen 3-month-old New Zealand white rabbits were divided into four equal groups, two treatment and two control. All treatment rabbits were administered daily injections of 15 mg/kg cortisone acetate for 4 days before and during the experimental period. An orthodontic appliance delivering a mesial force of 4 ounces was placed on the maxillary left first molar of all animals. For all groups, measurements of active tooth movement were made after 4, 7, 11, and 14 days. For two of the groups, appliances were removed on day 14, and additional measurements of relapse were made through day 21. With the use of radiodensitometric readings of the humerus bone and histology of the maxilla, osteoporosis was demonstrated in the treatment animals. Mean incremental and cumulative active tooth movement was three to four times greater (p < 0.0001) in the treatment rabbits than in the controls. The treatment group in which relapse was measured demonstrated 100% relapse on day 18, whereas the control group relapsed at a much lesser rate through day 21 and never achieved 100% relapse. Histologic findings appeared to support tooth movement results. In conclusion, the results of this study indicate that rabbits subjected to corticosteroid-induced osteoporosis undergo significantly more rapid orthodontic tooth movement and subsequent relapse than control animals.
Article
To investigate the mechanism of bone changes in hypervitaminosis D3, we compared contact radiographs, microangiograms by injection of Chinese ink, and corresponding histopathologic macrosections of 66 rabbits that received different doses of vitamin D3. In early stages, radiographs showed subperiosteal bone resorption and porotic cortical bone. The corresponding microangiograms showed proliferating vessels in the periosteum and cortical bone with associated dilatation of the Haversian and Volkmann's canals. When metastatic calcification fills these intracortical caverns or the intertrabecular spaces in the metaphysis and physis, the bone shows a diffuse increased density on radiographs. A dense band in the metaphysis reflects a thickening of calcified chondromatrix due to a hypotrophy of the distal metaphyseal capillaries. Six to 12 weeks after vitamin D3 withdrawal, radiographs showed further increased density of the cortical bone, due to newly formed bone and metastatic calcification. Alternating bands of increased and decreased density in the metaphysis and physis reflect the reinvasion of normal vasculature between growth cartilage and calcified chondromatrix, with normalization of endochondral ossification.
Article
This study explores the effects of a calcium-deficient diet on patterns of bone remodeling, and examines regional differences in the amount of bone lost. Skeletally mature female rabbits (n = 6) were fed a calcium-deficient diet (0.10% Ca2+ and 0.50% P) for 14 weeks. A separate group of rabbits (n = 4) were fed a maintenance diet (1.2% Ca2+ and 0.45% P). Bone mineral content, serum calcium, and serum phosphorus were measured each week during the experimental period. Following sacrifice, the L3 vertebra, femoral head, proximal tibial metaphysis, and tibial midshaft were analyzed histomorphometrically. Rabbits had 20% less vertebral bone after only 14 weeks of a calcium-deficient diet. As in human postmenopausal osteoporosis, bone loss in calcium-deficient rabbits occurs in the trabecular bone of the lumbar spine before that in the trabecular bone of the lower extremity. Calcium-deficient diets alone do not lead to increased osteoid volume or thickness. Because bone loss is relatively rapid and because the pattern of loss is similar in some respects to that found in humans, adult rabbits may provide an attractive model of calcium deficiency osteoporosis in a skeletally mature mammal in which remodeling is predominant over modeling.
Article
Vitamin D-depleted rats 4-weeks old were divided into three groups and given daily for 5 weeks cholecalciferol (0.25 microgram) or 1,25(OH)2D3 (0.075 microgram). The third group received no treatment with vitamin D sterols. A fourth control group was fed a diet containing vitamin D. The animals were killed after 5 weeks, plasma was prepared for calcium analysis, and incisors and molars were taken for histology. Growth was monitored throughout. Plasma calcium, body weight and the physical condition of the 1,25(OH)2D3-treated animals indicated that they were toxemic. The pulp-dentine complex of their incisors showed premature aging of fibroblasts and odontoblasts, disturbances in the dentinal matrix and osteodentine formation. That of molars was not affected. There was hypercementosis and bone-like tissue formation in the periodontal-ligament which in the incisors was considerably enlarged; some molars were ankylosed. The pulp-dentine complex of the incisors and molars of the rats in the remaining three groups appeared normal except for zones of hypomineralization in incisors of the third group. The supporting tissues of the teeth of the rats in the other three groups were within normal limits. Thus toxic doses of 1,25(OH)2D3 affected the dental tissues of both developing and mature teeth.
Article
Poor calcification of the teeth and the bones of the skull predisposes pet rabbits to dental disease. This study is a preliminary investigation into the dietary habits of pet rabbits. Owners were questioned about the feeding preferences of their pets. Manufacturers of rabbit foods were asked about the calcium, phosphorus and vitamin D content of their foods and how they had decided upon the formulation of their rations. Samples of rabbit food were analysed for calcium and phosphorus. Rabbits were found to be selective feeders. Rabbit food from pet shops consists of a mixed ration, of which the most commonly rejected ingredients were pellets and whole grain. The food manufacturers reported that calcium, phosphorus and vitamin D supplements are incorporated into the pellets. Food analyses demonstrated that rejection of the pellets and whole grain from the food can reduce a rabbit's calcium intake to below the minimum dietary requirement. The rabbit's unusual calcium metabolism is discussed. Calcium deficiency may cause osteomalacia but dietary excess may cause urolithiasis. Vitamin D deficiency may also exacerbate calcium deficiency. Recommendations are made for preventing calcium deficiency and dental disease in rabbits.
Differences in feeding rates and digestive efficiency of alternative experimental diets differing in cellulose or fiber and a secondary metabolite (the hydrolyzable tannin, tannic acid [TA]) were assessed with the herbivorous burrowing caviomorph rodent Octodon degus (degu). Degus live in open scrub subjected to summer droughts. The in vitro activity of the digestive enzyme sucrase was not significantly different between treatments with high and low TA. Analysis of the whole organism allowed us to conclude that in vitro analyses of enzymatic digestive activity and plant defenses cannot be used to explain and fully understand the physiological and behavioral effects of plant defenses on mammalian herbivores. We observed no body mass reduction due to effects of dietary treatments. O. degus seemed to compensate for nutritionally poor food by increasing gut content volume. We conclude that fiber and secondary compounds may influence feeding and digestive strategies and vice versa.
Article
The order Rodentia is vast, encompassing a large number of species with significant anatomical variations developed during natural adaptation to differing habitats. Many veterinarians have little knowledge of the anatomy of species other than the commoner domestic large herbivores and small carnivores. Clinicians require a basic knowledge of the relevant anatomy of species they are likely to be asked to treat. This article provides sufficient working knowledge of the oral and dental anatomy of those rodents commonly kept as pets to enable veterinarians to interpret clinical and radiographic findings when investigating suspected dental disease.
Article
To study the effect of increased occlusal vertical dimension on the fibre phenotypes of the superficial masseter muscle, the composition of myosin heavy-chains (MHC), myosin light-chains (MLC) and tropomyosin was investigated by sodium dodecyl sulphate-polyacrylamide gel electrophoresis and two-dimensional gel electrophoresis in conjunction with densitometric analysis in normal (control) and bite-opened (5.7 mm increase in the vertical dimension for 1 week) guinea-pigs. The superficial masseter contained two fast-type MHC isoforms, II-1 and II-2, in both the bite-opened and control groups; their relative content (mean±SD, n = 7) was 47.8±2.9% and 52.2±2.9%, in the bite-opened and 44.4±3.0% and 55.6±3.0% in control preparations, indicating no significant (p>0.05) changes in MHC composition in association with the bite opening. On the other hand, significant differences in MLC and tropomyosin composition were found between the two preparations. Although the MLC consisted of three components, LC1f, LC2f and LC3f, in both preparations, their relative content (mean±SD, n=7) was 37.1±2.4%, 49.6±1.6% and 13.2±3.2%, respectively, in the bite-opened and 28.1±3.1%, 50.9±1.6% and 21.0±3.5% in the control preparations, indicating that the bite opening induced a significant (p < 0.0001) increase in the relative content of LC1f at the expense of that of LC3f. Although the tropomyosin consisted of two components, TM-α and TMβ-, in both preparations, their relative content (mean±SD, n = 7) was 91.8%±1.9% and 8.2±1.9%, respectively, in the bite-opened and 95.9±0.7% and 4.±0.7% in the control preparations, showing a significant (p < 0.001) increase in the relative content of TM-β in relation to the bite opening. These results indicate that in guinea-pigs an increase in occlusal vertical dimension for 1 week changes the composition of MLC and tropomyosin, with no significant change in MHC, in the masseter muscle. These changes might be required to meet altered functional demands.
Article
This study, using 132 female rats, was designed to investigate whether oestrogen loss facilitates alveolar bone alterations induced by traumatic occlusion. Rats were ovariectomized (OVX) or underwent sham-operation (Sham). Seven days after surgery, half of the rats in each group were subjected to experimental traumatic occlusion (trauma), and the other half were left untreated. Thus, there were four groups: OVX+trauma, Sham+trauma, OVX, and Sham. Rats in each group were killed 1, 3, 5, 7, or 10 days after the introduction of occlusal trauma. The resected mandibles were processed without decalcification, and histomorphometric measurements were performed in the alveolar bone adjacent to the periodontal ligament of the first molar. The statistical assessment of the time- and group-specific differences by analysis of variance revealed significant differences between the OVX+trauma and Sham+trauma groups in the resorption parameters, but not in the formation parameters. The results show that the alveolar bone dynamics induced by traumatic occlusion are enhanced by oestrogen deficiency.
Article
Dental abnormalities are common in chinchillas, although knowledge of the lesions responsible for the clinical signs is incomplete. Animals bred in the UK were examined to gain further knowledge of dental disease in this chinchilla population. Dental abnormalities, particularly those related to tooth elongation, were detected on careful external examination of 35 per cent of apparently healthy chinchillas. Incisor abnormalities were seen on clinical examination in 55 per cent of chinchillas presented because of clinical illness. In all but one case, this occurred secondarily to crown elongation of the cheek teeth or to the absence of opposing teeth, rather than being a primary skeletal problem. Clinical signs commonly attributed to malocclusion, such as ventral mandibular swelling, weight loss, dysphagia, altered chewing pattern and changed food preferences, were not specific to malocclusion, being seen associated with coronal spike formation, root elongation and advanced periodontal lesions. Caries and resorptive lesions rarely caused clinical signs in this population, but were identified during 37 per cent of postmortem examinations. Congenital absence of teeth, skeletal malocclusion and pathological loss of teeth all resulted in significant clinical signs, but were rare. It is concluded that provision of a diet with physical properties more closely matching that of wild chinchillas should improve the dental health of captive animals.
Article
Orthodontic tooth movement and bone remodeling activity are dependent on systemic factors such as nutritional factors, metabolic bone diseases, age, and use of drugs. Therefore, a comprehensive review of the effects of these factors on orthodontic tooth movement is attempted in this article. Systemic hormones such as estrogen, androgen, and calcitonin are associated with an increase in bone mineral content, bone mass, and a decrease in the rate of bone resorption. Consequently, they could delay orthodontic tooth movement. On the contrary, thyroid hormones and corticosteroids might be involved in a more rapid orthodontic tooth movement during orthodontic therapy and have a less stable orthodontic result. Drugs such as bisphosphonates, vitamin D metabolites, and fluorides can probably cause a reduction of tooth movement after the orthodontic force is applied. Nonsteroidal anti-inflammatory drugs have also been shown to reduce bone resorption. Long-term administration of these drugs may therefore delay the necessary bone response to respective tooth-borne pressure and should not be administered for long periods of time to patients undergoing orthodontic tooth movement. Attention has also been focused on the effects of prostaglandins and leukotrienes in orthodontic tooth movement. It seems that they might have future clinical applications that could result in enhanced tooth movement. The use of the above drugs should be considered by every dentist in evaluating the treatment time and in planning treatment when tooth movement is attempted.
Article
Chinchillas are herbivorous rodents with teeth that all grow continuously. In captivity, they are commonly affected by dental disease. As the range of dental disease occurring in wild chinchillas is unknown, the dentition of museum specimens originally obtained from the wild was assessed and compared with specimens prepared from captive-bred animals. Skulls from wild-caught chinchillas showed minimal evidence of dental disease and the teeth were all short, cheek-tooth lengths averaging 5.9 mm. Cheek-tooth lengths in zoo specimens (average 6.6 mm), clinically normal (average 7.4 mm) and captive-bred animals with dental disease (average 10 mm) were significantly elongated by comparison (P<0.0001). Captive-bred specimens showed a wide range of tooth-related lesions. These results suggest that some aspect of captivity is responsible for the development of dental disease in chinchillas. It is suggested that the diet (its physical form and composition) is the main aetiological factor, and that provision of a diet closely matching that of wild chinchillas should significantly reduce the incidence of dental disease in captive animals.
Article
Rickets is a metabolic bone disorder characterized by osteopenic changes resulting from the failure of calcification of the osteoid matrix and absent mineralization of hypertrophic cartilage cells at the epiphyseal growth plates in growing primates, herbivores, swine, carnivores, and birds. The causes of rickets include inadequate dietary provision of calcium, phosphorus, and vitamin D. Osteomalacia in reptiles, simian bone disease in nonhuman primates, and osteodystrophia fibrosa (secondary hyperparathyroidism) or "bran disease" in herbivores are caused by a diet that has a much higher content of phosphorus than calcium, combined with inadequate exposure to direct sunlight. Medullary bone consists of interconnected spicules of bone resembling embryonic bone and is established in relation to the shell formation cycle of laying birds. Hypertrophic osteodystrophy develops in large-breed growing dogs, chickens, and guinea pigs and is possibly caused by vitamin C deficiency. Tibial dyschondroplasia is a defect in endochondral ossification characterized by a widened proximal tibial physis that is not penetrated by metaphyseal vascular sprouts, commonly found in growing broiler chickens, turkeys, and exotic birds.
Article
This contribution is meant to obtain basic data for feeding chinchillas (ingestion behaviour, feed and water intake) kept as companion animals. The chinchillas ingested more than 70% of their total feed intake during the dark phase (highest level of activity between 9:00 pm and 7:00 am). Daily amounts of feed intake varied between 2.5 (fresh grass) or 2.6 (hay) and 5.5 (pelleted complete diet) g of dry matter per 100 g of body weight. An offered mixed feed based on native components led to a selection of individual ingredients (high palatability: carob, beet pulp, sunflower seeds). The chinchillas' daily water intake varied between 30 (mixed feed in briquette form) and 40 ml (alfalfa cubes) and amounted on average between 1.5 and 3 ml/g of dry matter. Compared with rabbits or guinea-pigs, the chinchillas generally showed noticeable differences (rhythm of feed intake, palatability of individual ingredients, capacity for digestion, etc.) which must be considered in order to optimize the nutrition of this species.
Article
Hyperparathyroidism (HPT) occurs at an early age and has a high disability rate. Unfortunately, confirmed diagnosis in most patients is done at a very late stage, when the patients have shown typical symptoms and signs, and when treatment does not produce any desirable effect. It has become urgent to find a method that would detect early bone diseases in HPT to obtain time for the ideal treatment. This study evaluated the accuracy of high field magnetic resonance imaging (MRI) combined with spiral computed tomography (SCT) scan in detecting early bone diseases in HPT, through imaging techniques and histopathological examinations on an animal model of HPT. Eighty adult rabbits were randomly divided into two groups with forty in each. The control group was fed normal diet (Ca:P = 1:0.7); the experimental group was fed high phosphate diet (Ca:P = 1:7) for 3, 4, 5, or 6-month intervals to establish the animal model of HPT. The staging and imaging findings of the early bone diseases in HPT were determined by high field MRI and SCT scan at the 3rd, 4th, 5th and 6th month. Each rabbit was sacrificed after high field MRI and SCT scan, and the parathyroid and bones were removed for pathological examination to evaluate the accuracy of imaging diagnosis. Parathyroid histopathological studies revealed hyperplasia, osteoporosis and early cortical bone resorption. The bone diseases in HPT displayed different levels of low signal intensity on T(1)WI and low to intermediate signal intensity on T(2)WI in bone of stage 0, I, II or III, but showed correspondingly absent, probable, osteoporotic and subperiosteal cortical resorption on SCT scan. High field MRI combined with SCT scan not only detects early bone diseases in HPT, but also indicates staging, and might be a reliable method of studying early bone diseases in HPT.
Article
Eight normal dogs with no evidence of renal disease, weighing between 8 and 25 kg were imaged using contrast harmonic ultrasound after injection of a microbubble contrast medium. All dogs received three separate bolus injections of 0.05 ml of commercial contrast medium (Definity). Time/mean pixel value (MPV) curves were generated for selected regions in the cortex and medulla of the left kidney in each dog. Upslope, downslope, baseline, peak intensity, and time to peak were calculated for each zone. For a bolus injection, within the renal cortex (averaging all subjects) the upslope was 7.4 +/- 1.5 MPV/s, downslope was -0.4 +/- .2 MPV/s, baseline was 66.8 +/- 9.3 MPV, peak was 103.6 +/- 8.2 MPV, time to peak (from injection) was 12.8 +/- 5.3 s and from time of contrast medium reaching the kidney was 5.1 +/- 2.0 s. Within the renal medulla (averaging all subjects), upslope was 2.8 +/- 1.7 MPV/s, downslope was -0.3 +/- .2 MPV/s, baseline was 39.3 +/- 6.0 MPV, peak was 65.2 +/- 14.3 MPV, time to peak from injection was 20.9 +/- 6.4 s and from time of contrast reaching the kidney was 11.6 +/- 4.1 s. These baseline data may prove useful in the evaluation of dogs with diffuse disease or vascular compromise.
Article
Between 2002 and 2005 210 rabbits, 257 guinea pigs and 123 chinchillas were examined; oral disease was diagnosed in 38.1 per cent of the rabbits, 23.4 per cent of the guinea pigs and 32.5 per cent of the chinchillas. In the rabbits, the maxillary right P3, mandibular right P3, P4 and M1 and mandibular left P3, P4, and M1 were the teeth most frequently affected; in the guinea pigs, the mandibular right P4 and both the mandibular left incisor and P4 were most often affected; and in the chinchillas the maxillary right P4 and M1 and maxillary left P4 were most often affected. The incisors and first mandibular cheek teeth of the guinea pigs were significantly more often affected than those in the chinchillas or rabbits. Bilateral lesions of the maxillary cheek teeth were significantly more common in the chinchillas. The highest incidence of gingival hyperplasia was recorded in the rabbits. The incidence of gingival erosions and gingivitis were significantly higher in the chinchillas.
Abdomen. In Atlas der bildgebenden Diagnostik bei Heimtieren
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Radiographic signs of renal disease in rabbits
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Evaluation of a laryngoscope and a rigid endoscope for the examination of the oral cavity of small mammals Characterization of mandibular bone in a mouse model of chronic kidney disease
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Bone remodeling in hypervitaminosis D3. Radiologic-microangiographic-pathologic correlations.
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Anfragen aus der tierärztlichen Fütterungsberatung zu kleinen Nagern
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