Effects of a single intraperitoneal administration of cadmium on femoral bone structure in male rats

Background

Exposure to cadmium (Cd) is considered a risk factor for various bone diseases in humans and experimental animals. This study investigated the acute effects of Cd on femoral bone structure of adult male rats after a single intraperitoneal administration.

Methods

Ten 4-month-old male Wistar rats were injected intraperitoneally with a single dose of 2 mg CdCl₂/kg body weight and killed 36 h after the Cd had been injected. Ten 4-month-old males served as a control group. Differences in body weight, femoral weight, femoral length and histological structure of the femur were evaluated between the two groups of rats. The unpaired Student''s t-test was used for establishment of statistical significance.

Results

A single intraperitoneal administration of Cd had no significant effect on the body weight, femoral weight or femoral length. On the other hand, histological changes were significant. Rats exposed to Cd had significantly higher values of area, perimeter, maximum and minimum diameters of the primary osteons'' vascular canals and Haversian canals. In contrast, a significant decrease in all variables of the secondary osteons was observed in these rats.

Conclusions

The results indicate that, as expected, a single intraperitoneal administration of 2 mg CdCl₂/kg body weight had no impact on macroscopic structure of rat''s femora; however, it affected the size of vascular canals of primary osteons, Haversian canals, and secondary osteons.     

Sex-related variation in compact bone microstructure of the femoral diaphysis in juvenile rabbits

Background

While gross morphological changes in the skeleton between males and females are well know, differences between sexes in the histomorphology are less known. It is important to have knowledge on the bone structure of rabbits, as this is a widely used species in biomedical research. A study was performed to evaluate the association between sex and the compact bone morphology of the femoral diaphysis in juvenile rabbits.

Methods

Seventeen clinically healthy 2–3 month-old rabbits (9 females, 8 males) were included in the study. The rabbits were euthanized and the right femur was sampled for analysis. 70–80 microns thick bone sections of the femoral diaphysis were prepared using standard histological equipment. The qualitative histological characteristics were determined according to internationally accepted classification systems while the quantitative parameters were assessed using the software Scion Image. Areas, perimeters, minimum and maximum diameters of primary osteons'' vascular canals, Haversian canals and secondary osteons were measured. Additionally, blood plasma concentrations of progesterone, corticosterone, IGF-I, testosterone and estradiol were analyzed.

Results

Qualitative histological characteristics were similar for both sexes. However, variations of certain quantitative histological characteristics were identified. Measured parameters of the primary osteons'' vascular canals were higher in males than for females. On the other hand, females had significant higher values of secondary osteons parameters. Differences in Haversian canals parameters were only significant for minimum diameter.

Conclusion

The study demonstrated that quantitative histological characteristics of compact bone tissue of the femoral diaphysis in juvenile rabbits were sex dependent. The variations may be associated with different growth and modeling of the femur through influence by sex-specific steroids, mechanical loads, genetic factors and a multitude of other sources. The results can be applied in experimental studies focusing on comparison of the skeletal biology of the sexes.     

Structural changes in femoral bone tissue of rats after subchronic peroral exposure to selenium

Background

The role of selenium (Se) on bone microarchitecture is still poorly understood. The present study aims to investigate the macroscopic and microscopic structures of femoral bone tissue in adult male rats after subchronic peroral administration of Se.

Methods

Twenty one-month-old male Wistar rats were randomly divided into two experimental groups. In the first group (Se group) young males were exposed to 5 mg Na₂SeO₃/L in drinking water, for 90 days. Ten one-month-old males without Se administration served as a control group. At the end of the experiment, macroscopic and microscopic structures of the femurs were analysed using analytical scales, sliding instrument, and polarized light microscopy.

Results

The body weight, femoral length and cortical bone thickness were significantly decreased in Se group rats. These rats also displayed different microstructure in the middle part of the femur, both in medial and lateral views, where vascular canals expanded into the central area of the bone while, in control rats, these canals occurred only near the endosteal surfaces. Additionally, a smaller number of primary and secondary osteons was identified in Se group rats. Histomorphometric analyses revealed significant increases for area, perimeter, maximum and minimum diameters of primary osteons’ vascular canals but significant reductions for all measured variables of Haversian canals and secondary osteons.

Conclusions

Se negatively affected the macroscopic and microscopic structures of femoral bone tissue in adult male rats. The results contribute to the knowledge on damaging impact of Se on bone.     

Changes in compact bone microstructure of rats subchronically exposed to cadmium

Background

Chronic exposure to cadmium (Cd), even at low concentrations, has an adverse impact on the skeletal system. Histologically, primary and secondary osteons as basic structural elements of compact bone can also be affected by several toxicants leading to changes in bone vascularization and mechanical properties of the bone. The current study was designed to investigate the effect of subchronic peroral exposure to Cd on femoral bone structure including histomorphometry of the osteons in adult male rats.In our study, 20 one-month-old male Wistar rats were randomly divided into two experimental groups. In the first group, young males received a drinking water containing 30 mg of CdCl₂/L, for 90 days. Ten one-month-old males without Cd intoxication served as a control group. After 90 days of daily peroral exposure, body weight, femoral weight, femoral length, cortical bone thickness and histological structure of the femora were analysed.

Results

We found that subchronic peroral application of Cd had no significant effect on body weight, femoral length and cortical bone thickness in adult rats. On the other hand, femoral weight was significantly increased (P < 0.05) in Cd-intoxicated rats. These rats also displayed different microstructure in the middle part of the compact bone where vascular canals expanded into central area of substantia compacta and supplied primary and secondary osteons. Additionally, a few resorption lacunae which are connected with an early stage of osteoporosis were identified in these individuals. Histomorphometrical evaluations showed that all variables (area, perimeter, maximum and minimum diameter) of the primary osteons’ vascular canals, Haversian canals and secondary osteons were significantly decreased (P < 0.05) in the Cd group rats. This fact points to alterations in bone vascularization.

Conclusions

Subchronic peroral exposure to Cd significantly influences femoral weight and histological structure of compact bone in adult male rats. It induces an early stage of osteoporosis and causes reduced bone vascularization. Histomorphometrical changes of primary and secondary osteons allow for the conclusion that the bone mechanical properties could be weakened in the Cd group rats. The current study significantly expands the knowledge on damaging action of Cd on the bone.     

Sex-related variations in bone microstructure of rabbits intramuscularly exposed to patulin

Background

Patulin, a toxic mold metabolite, has been found as natural contaminant of processed fruits, most notably apples, apple juices and other apple-based products. A number of adverse health effects in humans and animals are associated with patulin intoxication. The current study was performed to analyse possible toxic effects of patulin on femoral bone microstructure in adult rabbits in detail. Fourteen clinically healthy four-month-old rabbits of both sexes (6 males and 8 females) were included in the study. Animals from the experimental groups (group E♂, n = 3; group E♀, n = 4) were injected intramuscularly with patulin at dose 10 μg/kg body weight two times a week for 28 days. The dose of patulin was estimated based on the maximum permitted level of patulin for apple products intended for infants and young children. Three males and four females without patulin administration served as controls (groups C♂ and C♀). Cortical bone thickness and qualitative and quantitative histological characteristics of compact bone tissue were investigated.

Results

Intramuscular applications of patulin significantly increased the thickness of cortical bone in both sexes of rabbits. In patulin-exposed males, an absence of primary vascular longitudinal bone tissue near the endosteal border was observed, which could be associated with intensive bone remodeling. Femoral diaphyses of females displayed a lower number of secondary osteons in the middle part of the substantia compacta, and occurrence of the osteons near the periosteum. This could indicate alterations in bone turnover. Histomorphometrical evaluations showed significantly increased sizes of the primary osteons’ vascular canals (P < 0.05) in males exposed to patulin possibly due to mycotoxin-induced increased levels of testosterone.

Conclusions

This study demonstrates significant impact of intramuscular application of patulin on bone microstructure in adult rabbits. Moreover, we have found that the effects of patulin on qualitative and quantitative histological characteristics of compact bone are sex-dependent.     

Intra-arterial delivery of triolein emulsion increases vascular permeability in skeletal muscles of rabbits

Background

To test the hypothesis that triolein emulsion will increase vascular permeability of skeletal muscle.

Methods

Triolein emulsion was infused into the superficial femoral artery in rabbits (triolein group, n = 12). As a control, saline was infused (saline group, n = 18). Pre- and post-contrast T1-weighted MR images were obtained two hours after infusion. The MR images were qualitatively and quantitatively evaluated by assessing the contrast enhancement of the ipsilateral muscles. Histologic examination was performed in all rabbits.

Results

The ipsilateral muscles of the rabbits in the triolein group showed contrast enhancement, as opposed to in the ipsilateral muscles of the rabbits in the saline group. The contrast enhancement of the lesions was statistically significant (p < 0.001). Histologic findings showed that most examination areas of the triolein and saline groups had a normal appearance.

Conclusion

Rabbit thigh muscle revealed significantly increased vascular permeability with triolein emulsion; this was clearly demonstrated on the postcontrast MR images.     

Modular hybrid total hip arthroplasty. Experimental study in dogs

Background

This prospective experimental study evaluated the surgical procedure and results of modular hybrid total hip arthroplasty in dogs.

Methods

Ten skeletally mature healthy mongrel dogs with weights varying between 19 and 27 kg were used. Cemented modular femoral stems and uncemented porous-coated acetabular cups were employed. Clinical and radiographic evaluations were performed before surgery and at 30, 60, 90, 120, 180 and 360 days post-operation.

Results

Excellent weight bearing was noticed in the operated limb in seven dogs. Dislocation followed by loosening of the prosthesis was noticed in two dogs, which were therefore properly treated with a femoral head osteotomy. Femoral fracture occurred in one dog, which was promptly treated with full implant removal and femoral osteosynthesis.

Conclusions

The canine modular hybrid total hip arthroplasty provided excellent functionality of the operated limb.     

Treatment of rabbit cheyletiellosis with selamectin or ivermectin: a retrospective case study

Background

A retrospective study of rabbits treated against cheyletiellosis was performed to evaluate the efficacy and safety of selamectin or ivermectin in clinical practice.

Methods

Medical records from 53 rabbits with microscopically confirmed Cheyletiella infestation were collected from two small animal clinics. The rabbits were divided into three groups, based on treatment protocols. Group 1 included 11 rabbits treated with ivermectin injections at 200–476 μg kg^-1 subcutaneously 2–3 times, with a mean interval of 11 days. In Group 2, 27 rabbits were treated with a combination of subcutaneous ivermectin injections (range 618–2185 μgkg^-1) and oral ivermectin (range 616–2732 μgkg^-1) administered by the owners, 3–6 times at 10 days interval. The last group (Group 3) included 15 rabbits treated with selamectin spot-on applications of 6.2–20,0 mgkg^-1, 1–3 times with an interval of 2–4 weeks. Follow-up time was 4 months–4.5 years.

Results

Rabbits in remission were 9/11 (81,8%), 14/27 (51,9%) and 12/15 (80,8%) in groups 1, 2 and 3, respectively.

Conclusion

All treatment protocols seemed to be sufficiently effective and safe for practice use. Though very high doses were used in Group 2 (ivermectin injections followed by oral administration), the protocol seemed less efficacious compared to ivermectin injections (Group 1) and selamectin spot on (Group 3), respectively, although not statistically significant. Controlled prospective studies including larger groups are needed to further evaluate efficacy of the treatment protocols.     

Simultaneous subchronic exposure to selenium and diazinon as possible risk factor for osteoporosis in adult male rats

Background

Osteoporosis and its main health outcome, fragility fractures, are large and escalating health problems. Skeletal damage may be the critical result of low-level prolonged exposure to several xenobiotics in the general population, but the mechanisms of their adverse effects are not clearly understood. The current study was aimed to investigate the possible ability of simultaneous subchronic peroral administration of selenium (Se) and diazinon (DZN) to induce changes in bone of adult male rats.In our study, twenty 1-month-old male Wistar rats were randomly divided into two experimental groups. In the first group, young males were exposed to 5 mg Na₂SeO₃/L and 40 mg of DZN/L in drinking water, for 90 days. Ten 1-month-old males without Se and DZN intoxication served as a control group. At the end of the experiment, macroscopic and microscopic structures of the femurs were analysed using analytical scales, sliding instrument, and polarized light microscopy.

Results

The body weight, femoral length and cortical bone thickness were significantly decreased in rats simultaneously exposed to Se and DZN (P < 0.05). These rats also displayed different microstructure in the middle part of the compact bone where vascular canals expanded into central area of substantia compacta. The canals occurred only near endosteal surfaces in rats from the control group. Additionally, a smaller number of primary and secondary osteons, as well as a few resorption lacunae were observed near endosteal surfaces in rats simultaneously administered to Se and DZN. The resorption lacunae as typical structures of bone resorption manifestation are connected with an early stage of osteoporosis. Histomorphometric analysis revealed that area, perimeter, maximum and minimum diameters of primary osteons’ vascular canals were significantly increased (P < 0.05) in the Se-DZN-exposed rats. On the other hand, all measured variables of Haversian canals and secondary osteons were considerable reduced (P < 0.05) in these rats.

Conclusions

Simultaneous subchronic peroral exposure to Se and DZN induces changes in macroscopic and microscopic structures of the femurs in adult male rats, and also it can be considered as possible risk factor for osteoporosis. The current study contributes to the knowledge on damaging impact of several xenobiotics on the bone.     

Further investigation of risk elements content in the bones of wild rodents from a polluted area in Slovakia

Background

Wild rodents are suitable for monitoring environmental pollution and exposure risk assessment for people living in contaminated areas. The content of selected risk elements in the femora of bank vole (Myodes glareolus), yellow-necked mouse (Apodemus flavicollis) and wood mouse (Apodemus sylvaticus) was estimated from the Kolíňany area of Slovakia, which is characterized by a high degree of environmental pollution. The rodents were trapped in February 2011 using standard theriological methods. All animals (n = 32) were adult males in good physical condition. The concentrations of Fe, Cu, Zn and Ni in their bones were determined by atomic absorption spectrophotometry.

Results

The highest concentrations of Fe and Cu were detected in the bones of yellow-necked mouse. Significant differences were observed for the content of Fe between A. flavicollis and M. glareolus (P < 0.05). The highest levels of Zn and Ni were found in the femora of wood mouse; however, significant differences were not detected between the rodents. Moreover, the concentrations of Cu, Zn and Ni were significantly higher in the bones of all three species (P < 0.05) in comparison with the values obtained in the same animal species at the same site in February 2007.

Conclusions

Our results demonstrate an increased accumulation of Cu, Zn and Ni in the femora of M. glareolus, A. flavicollis and A. sylvaticus from the Kolíňany area and thus indicate towards ongoing contamination of this locality.     

Effects of a multi-enzyme complex on growth performance,nutrient utilization and bone mineralization of meat duck

Background

Previous studies with broiler have shown dietary supplementation with multi-enzyme complex containing non-starch polysaccharides (NSP) degrading enzymes and phytase is efficient in releasing phosphorus (P), calcium (Ca), energy and amino acids from corn-soybean meal diets or corn-sorghum diets, hence compensating considerable levels of nutrients in formulation. Notwithstanding, such potentials have not been well defined in duck nutrition. Giving China being the largest duck producing country, we conducted this study to establish adequate specifications of major nutrients along with multi-enzyme complex to meat duck from day-old to slaughter, focusing on performance, utilization of nutrients and bone mineralization. Five dietary treatments were: Positive control (PC,T1 ): the nutrients concentration of diet for 1 to 14 d of age were apparent metabolizable energy(AME) 2,800 kcal/kg, crude protein (CP)19.39%, Ca 0.85%, available phosphorus (avP) 0.42%; for 15 to 35 d of age these parameters were AME 2,900 kcal/kg, CP 16.47%,Ca 0.76%,avP 0.38%; Negative control 1(NC1,T2), the AME and digestible amino acids (DAA) were reduced by 70 kcal/kg and 2.0%, avP and Ca by 1.0 g/kg from PC diet; Negative control 2( NC2,T4), the down-spec from PC diet was AME 100 kcal/kg, DAA 2.5%, avP 1.5 g/kg and Ca 1.2 g/kg; The enzyme complex was added at the same dosage (200 mL/ 1,000 kg) on NC1 (T3) and NC2 (T5) diets.

Results

Comparing with the ducks fed on T1, T3 and T5 diets, the birds fed on NC2 diet showed the lowest (P < 0.05) body weight ( d 14 and 35), feed intake (d 35), tibia ash, Ca and P contents (d 14 and 35), and the utilization of nutrients (P < 0.05). The supplementation with the enzyme complex to the NC diets restored growth rate, utilization of nutrients and bone mineralization to the level of the PC diet, and increased AME by 60 kcal/kg and 117 kcal/kg, respectively for the NC1 and NC2 diets.

Conclusion

These results suggest that down-spec AME by 100 kcal/kg, DAA by 2.5%, avP by 1.5 g/kg and Ca by 1.2 g/kg caused detrimental effects on duck performance compared with those fed on the PC diet, and these performance losses can be compensated by the addition of the multiple-enzyme complex.     

Repeated post-exercise administration with a mixture of leucine and glucose alters the plasma amino acid profile in Standardbred trotters

Background

The branched chain amino acid leucine is a potent stimulator of insulin secretion. Used in combination with glucose it can increase the insulin response and the post exercise re-synthesis of glycogen in man. Decreased plasma amino acid concentrations have been reported after intravenous or per oral administration of leucine in man as well as after a single per oral dose in horses. In man, a negative correlation between the insulin response and the concentrations of isoleucine, valine and methionine have been shown but results from horses are lacking. This study aims to determine the effect of repeated per oral administration with a mixture of glucose and leucine on the free amino acid profile and the insulin response in horses after glycogen-depleting exercise.

Methods

In a crossover design, after a glycogen depleting exercise, twelve Standardbred trotters received either repeated oral boluses of glucose, 1 g/kg body weight (BW) at 0, 2 and 4 h with addition of leucine 0.1 g/kg BW at 0 and 4 h (GLU+LEU), or repeated boluses of water at 0, 2 and 4 h (CON). Blood samples for analysis of glucose, insulin and amino acid concentrations were collected prior to exercise and over a 6 h post-exercise period. A mixed model approach was used for the statistical analyses.

Results

Plasma leucine, isoleucine, valine, tyrosine and phenylalanine concentrations increased after exercise. Post-exercise serum glucose and plasma insulin response were significantly higher in the GLU+LEU treatment compared to the CON treatment. Plasma leucine concentrations increased after supplementation. During the post-exercise period isoleucine, valine and methionine concentrations decreased in both treatments but were significantly lower in the GLU+LEU treatment. There was no correlation between the insulin response and the response in plasma leucine, isoleucine, valine and methionine.

Conclusions

Repeated post-exercise administration with a mixture of leucine and glucose caused a marked insulin response and altered the plasma amino acid profile in horses in a similar manner as described in man. However, the decreases seen in plasma amino acids in horses seem to be related more to an effect of leucine and not to the insulin response as seen in man.     

Effect of sedation with detomidine and butorphanol on pulmonary gas exchange in the horse

Background

Sedation with α₂-agonists in the horse is reported to be accompanied by impairment of arterial oxygenation. The present study was undertaken to investigate pulmonary gas exchange using the Multiple Inert Gas Elimination Technique (MIGET), during sedation with the α₂-agonist detomidine alone and in combination with the opioid butorphanol.

Methods

Seven Standardbred trotter horses aged 3–7 years and weighing 380–520 kg, were studied. The protocol consisted of three consecutive measurements; in the unsedated horse, after intravenous administration of detomidine (0.02 mg/kg) and after subsequent butorphanol administration (0.025 mg/kg). Pulmonary function and haemodynamic effects were investigated. The distribution of ventilation-perfusion ratios (V_A/Q) was estimated with MIGET.

Results

During detomidine sedation, arterial oxygen tension (PaO₂) decreased (12.8 ± 0.7 to 10.8 ± 1.2 kPa) and arterial carbon dioxide tension (PaCO₂) increased (5.9 ± 0.3 to 6.1 ± 0.2 kPa) compared to measurements in the unsedated horse. Mismatch between ventilation and perfusion in the lungs was evident, but no increase in intrapulmonary shunt could be detected. Respiratory rate and minute ventilation did not change. Heart rate and cardiac output decreased, while pulmonary and systemic blood pressure and vascular resistance increased. Addition of butorphanol resulted in a significant decrease in ventilation and increase in PaCO₂. Alveolar-arterial oxygen content difference P(A-a)O₂ remained impaired after butorphanol administration, the V_A/Q distribution improved as the decreased ventilation and persistent low blood flow was well matched. Also after subsequent butorphanol no increase in intrapulmonary shunt was evident.

Conclusion

The results of the present study suggest that both pulmonary and cardiovascular factors contribute to the impaired pulmonary gas exchange during detomidine and butorphanol sedation in the horse.     

Fixed-time artificial insemination in beef cattle

Background

The study was designed to test the effect of fixed-time artificial insemination (fixed-AI) after the slightly modified Ovsynch protocol on the pregnancy rate in beef cattle in Finnish field conditions. The modification was aimed to optimize the number of offsprings per AI dose.

Methods

Ninety Charolais cows and heifers were entered into the program an average of 1.8 times. Thus, 164 animal cases were included. Animals were administered 10-12 μg of buserelin. Seven days later animals without a corpus luteum (CL) were rejected (20.7%) while the remaining 130 cases with a CL were administered prostaglandin F_2α, followed 48 h later with a second injection of buserelin (8-10 μg). Fixed-AI was performed 16-20 hours after the last injection.

Results

The pregnancy rate was 51.5% (67/130). The pregnancy rate after a short interval (50-70 d) from calving to entering the program was significantly higher than that after a long interval (>70 d).

Conclusion

This protocol seems to give acceptable pregnancy results in beef herds and its effect on saving labour is notable.     

Yellow-necked mice (Apodemus flavicollis) and bank voles (Myodes glareolus) as zoomonitors of environmental contamination at a polluted area in Slovakia

Background

Free-living wild rodents are often used as zoomonitors of environmental contamination. In the present study, accumulation of cadmium (Cd), copper (Cu), iron (Fe), and zinc (Zn) in critical organs of yellow-necked mice (Apodemus flavicollis) and bank voles (Myodes glareolus) trapped in a polluted area in Nováky, Slovakia was investigated.

Methods

Yellow-necked mice (n = 8) and bank voles (n = 10) were collected using standard theriological methods for wood ecosystems. All animals were adult males in good physical condition. The concentrations of Cd, Cu, Fe, and Zn in the liver, kidney, and bone were determined by atomic absorption spectrophotometry.

Results

The highest concentrations of Cd and Zn were found in the bone of both species while Cu and Fe accumulated mainly in kidney or liver. Significant higher concentrations of Cd and Cu were detected in the liver of bank voles than in yellow-necked mice. Similar significant higher levels of Cd and Zn were found in the bone of bank voles. In contrast, significant higher concentrations of Cu and Fe were present in the kidney of yellow-necked mice.

Conclusions

In the yellow-necked mouse and bank vole, bone seems to accumulate Cd and Zn following prolonged exposure. On the contrary, kidney and liver store Cu and Fe after a long-term environmental exposure. In the present study, bank voles seemed to be more heavy metal loaded zoomonitors than yellow-necked mice.     

Association between average daily gain,faecal dry matter content and concentration of Lawsonia intracellularis in faeces

Background

The objective of this study was to investigate the association between average daily gain and the number of Lawsonia intracellularis bacteria in faeces of growing pigs with different levels of diarrhoea.

Methods

A longitudinal field study (n = 150 pigs) was performed in a Danish herd from day 29 to 47 post weaning. Every third day all pigs were weighed, subjected to a clinical examination and faecal samples were obtained. Faecal samples were subjected to dry matter determination and absolute quantification by PCR for L. intracellularis and porcine circovirus type 2 (PCV2). Association between average daily gain, faecal dry matter content, numbers of L. intracellularis bacteria and PCV2 genome copies in faeces was investigated in a multilevel mixed-effects linear model.

Results

Increasing numbers of L. intracellularis log₁₀ bacteria/g faeces were significantly associated with decreasing average daily gain (P < 0.001). The association was decreasing with increasing faecal dry matter content (P < 0.01). The number of PCV2 log₁₀ copies/g faeces was not significantly associated with average daily gain of the pigs (P > 0.5).

Conclusion

The results suggest a potential application of a PCR quantifying L. intracellularis in growing pigs. Faecal dry matter content must be taken into consideration in interpretation of such test results.     

Effects of dietary phytoestrogens on plasma testosterone and triiodothyronine (T3) levels in male goat kids

Background

Exposure to xenoestrogens in humans and animals has gained increasing attention due to the effects of these compounds on reproduction. The present study was undertaken to investigate the influence of low-dose dietary phytoestrogen exposure, i.e. a mixture of genistein, daidzein, biochanin A and formononetin, on the establishment of testosterone production during puberty in male goat kids.

Methods

Goat kids at the age of 3 months received either a standard diet or a diet supplemented with phytoestrogens (3 - 4 mg/kg/day) for ~3 months. Plasma testosterone and total and free triiodothyronine (T₃) concentrations were determined weekly. Testicular levels of testosterone and cAMP were measured at the end of the experiment. Repeated measurement analysis of variance using the MIXED procedure on the generated averages, according to the Statistical Analysis System program package (Release 6.12, 1996, SAS Institute Inc., Cary, NC, USA) was carried out.

Results

No significant difference in plasma testosterone concentration between the groups was detected during the first 7 weeks. However, at the age of 5 months (i.e. October 1, week 8) phytoestrogen-treated animals showed significantly higher testosterone concentrations than control animals (37.5 nmol/l vs 19.1 nmol/l). This elevation was preceded by a rise in plasma total T₃ that occurred on September 17 (week 6). A slightly higher concentration of free T₃ was detected in the phytoestrogen group at the same time point, but it was not until October 8 and 15 (week 9 and 10) that a significant difference was found between the groups. At the termination of the experiment, testicular cAMP levels were significantly lower in goats fed a phytoestrogen-supplemented diet. Phytoestrogen-fed animals also had lower plasma and testicular testosterone concentrations, but these differences were not statistically significant.

Conclusion

Our findings suggest that phytoestrogens can stimulate testosterone synthesis during puberty in male goats by increasing the secretion of T₃; a hormone known to stimulate Leydig cell steroidogenesis. It is possible that feedback signalling underlies the tendency towards decreased steroid production at the end of the experiment.     

The effects of repeated intravenous iohexol administration on renal function in healthy beagles – a preliminary report

Background

Contrast induced nephrotoxicity (CIN) is a well described syndrome in humans undergoing contrast medium examinations. To date CIN has received minimal attention in the veterinary literature despite increasing use of contrast medium examinations in computed tomographic studies.

Methods

This prospective study evaluated the effect of 1290 mg/kg iohexol given intravenously to 5 normal beagle dogs in a divided dose at an interval of 6–8 weeks. Renal function was evaluated by means of scintigraphically determined glomerular filtration rate (GFR) and a variety of laboratory assays.

Results

Only GFR showed a significant decrease (17%) after the second injection but not to a clinically or pathologically significant level.

Conclusions

No clinically significant effect of repeated contrast medium administration was determined in this limited study. However in dogs with reduced renal function the risk of CIN is likely to increase dramatically post contrast administration.     

Estimation of endogenous protein and amino acid ileal losses in weaned piglets by regression analysis using diets with graded levels of casein

Background

Many studies have investigated endogenous loss of proteins and amino acids (AAs) at the ileal level in growing pigs. However, only a few studies have researched this subject in piglets. Knowledge regarding AA ileal digestibility in piglets would be helpful during the formulation of diets for weaning piglets, rather than just using coefficients obtained in growing pigs. Therefore, in this study, we sought to estimate endogenous protein and AA ileal losses in piglets. Furthermore, apparent and true ileal digestibility (AID and TID) of protein and AAs from casein were measured.

Results

The average flow of protein was 20.8 g/kg of dry matter intake (DMI). Basal protein loss, as estimated by regression, was 16.9 g/kg DMI. Glutamic acid, arginine, and aspartic acid (2.2, 1.4, and 1.2 g/kg DMI, respectively) were the AAs for which greater losses were seen. The AID of protein and AAs increased as the protein level in the diet increased. A higher increment in AID was observed between diets with 80 and160 g CP/kg of feed; this finding was mainly attributable to increases in glycine and arginine (46.1% and 18%, respectively). The TID of protein was 97.8, and the TID of AAs varied from 93.9 for histidine to 100.2 for phenylalanine.

Conclusions

The basal endogenous protein loss in piglets was 16.9 g/kg DMI. Endogenous protein was rich in glutamic acid, aspartic acid, and arginine, which represented 32.7% of endogenous protein loss in weaning piglets. The TID of casein was high and varied from 93.0 for histidine to 100.2 for phenylalanine.     

Magnetic resonance imaging anatomy of the rabbit brain at 3?T

Background

Rabbits are widely accepted as an animal model in neuroscience research. They also represent very popular pet animals, and, in selected clinical cases with neurological signs, magnetic resonance imaging (MRI) may be indicated for imaging the rabbit brain. Literature on the normal MRI anatomy of the rabbit brain and associated structures as well as related reference values is sparse. Therefore, it was the purpose of this study to generate an MRI atlas of the normal rabbit brain including the pituitary gland, the cranial nerves and major vessels by the use of a 3 T magnet.

Results

Based on transverse, dorsal and sagittal T2-weighted (T2w) and pre- and post-contrast 3D T1-weighted (T1w) sequences, 60 intracranial structures were identified and labeled. Typical features of a lissencephalic brain type were described. In the 5 investigated rabbits, on T1w images a crescent-shaped hyperintense area caudodorsally in the pituitary gland most likely corresponded to a part of the neurohypophysis. The optic, trigeminal, and in part, the facial, vestibulocochlear and trochlear nerves were identified. Mild contrast enhancement of the trigeminal nerve was present in all rabbits. Absolute and relative size of the pituitary gland, midline area of the cranial and caudal cranial fossa and height of the tel- and diencephalon, 3rd and 4th ventricles were also determined.

Conclusions

These data established normal MRI appearance and measurements of the rabbit brain. Results provide reference for research studies in rabbits and, in rare instances, clinical cases in veterinary medicine.

Electronic supplementary material

The online version of this article (doi:10.1186/s13028-015-0139-6) contains supplementary material, which is available to authorized users.