EFFECTS OF NATURAL ULTRAVIOLET RADIATION ON 25-HYDROXYVITAMIN D3 CONCENTRATIONS IN FEMALE GUINEA PIGS (CAVIA PORCELLUS)

Vertebrates have 2 methods of acquiring vitamin D: through the diet and/or secondary to exposure to ultraviolet B (UVB) radiation. Although some species (e.g., dogs) can only acquire vitamin D through their diet, many others also utilize UVB radiation to generate vitamin D. Prior to their extirpation, guinea pigs were naturally exposed to varying levels of sunlight (UVB) in their native habitat; however, in captivity we do not routinely recommend UVB radiation for these animals. Recently, it has been shown that captive guinea pigs can synthesize 25-hydroxyvitamin D (25-OHD₃) after exposure to UVB lightbulbs. However, it is not known how natural sunlight impacts 25-OHD₃ concentrations in this species. The purpose of this study was to determine whether 25-OHD₃ concentrations in female guinea pigs exposed to natural sunlight would increase as a result of UVB exposure. Eight adult female guinea pigs were used for this study. The animals were held indoors during winter months and then placed outside in the spring when temperatures were appropriate. Blood samples were collected before the animals were placed outdoors (baseline) and 30 days after being exposed to natural sunlight. There was a significant difference in 25-OHD₃ concentrations over time (P = 0.006) and values collected after the guinea pigs were housed outdoors were 1.8 times higher than baseline. This study confirmed that female guinea pigs can increase 25-OHD₃ concentrations after exposure to natural sunlight. This suggests that these animals have conserved this pathway despite domestication, and supplementation should be considered to optimize captive guinea pig habitats.     

Effects of Ultraviolet Radiation on Serum 25-Hydroxyvitamin D Concentrations in Captive Chinchillas (Chinchilla laniger)

Vitamin D is an important hormone in vertebrates, and most animals acquire this hormone through their diet and/or exposure to ultraviolet B (UVB) radiation. To date, no study has determined how chinchillas (Chinchilla laniger) acquire vitamin D. The objective of this study was to determine whether exposure to UVB radiation had an effect on serum 25-hydroxyvitamin D levels in captive chinchillas. Overall, 10 juvenile chinchillas were used for this scientific investigation. Baseline blood samples were collected from the animals while under isoflurane anesthesia to determine their serum 25-hydroxyvitamin D concentrations. The chinchillas were then randomly assigned to 2 treatment groups: Group A, 12 hours of UVB exposure per day and Group B, no UVB exposure. At the end of the study (Day 16), a second blood sample was collected from each animal while again under isoflurane anesthesia to measure serum 25-hydroxyvitamin D concentrations. Mean ± standard deviation serum 25-hydroxyvitamin D concentrations differed significantly (P = 0.048) between juvenile chinchillas provided supplemental UVB radiation (189.0 ± 102.7 nmol/L) and those not provided supplemental UVB radiation (87.8 ± 34.4 nmol/L). This study found that exposing juvenile chinchillas to UVB radiation significantly increased their circulating serum 25-hydroxyvitamin D levels. Because vitamin D is an essential hormone in vertebrates, these findings suggest that the provision of UVB radiation to captive chinchillas may be important. Further research to elucidate the importance of 25-hydroxyvitamin D and UVB radiation in captive chinchillas is required.     

Impacts of UVB provision and dietary calcium content on serum vitamin D3, growth rates,skeletal structure and coloration in captive oriental fire‐bellied toads (Bombina orientalis)

Many amphibian species are dependent on ex situ conservation interventions for their long‐term persistence. However, projects have been jeopardised by husbandry issues involving poor calcium metabolism and nutritional metabolic bone disease (NMBD). Healthy calcium metabolism requires appropriate dietary calcium content and access to vitamin D₃. In many animals, vitamin D₃ can be photobiosynthesised in skin exposed to UVB radiation, as well as extracted from the diet, but the extent of vitamin D₃ photobiosynthesis in amphibians is poorly known. Additionally, prey insects for captive amphibians are deficient in calcium and calcium content must be artificially increased, but the effects of different levels of augmentation and their interaction with UVB exposure are also little understood. We fed captive fire‐bellied toads (Bombina orientalis) with crickets augmented to contain 5% and 10% calcium and housed them with and without UVB exposure. Despite additional dietary vitamin D₃ supplementation, we found that toads exposed to UVB radiation exhibited significantly higher serum vitamin D₃ levels, indicating that this species may partly rely on photobiosynthesis sources of vitamin D₃. These data are the first to show a direct link between UVB exposure and serum vitamin D₃ in an amphibian. We found significant positive effects of UVB exposure and 10% dietary calcium content on skeletal structure, as well as complex interactions between treatments. We also found UVB radiation exposure resulted in more rapid natural coloration acquisition. Together, this indicates that standard calcium plus vitamin D₃ supplementation methods may not fully substitute for UVB exposure and for increased feeder insect calcium content. This may have implications for the success of ex situ amphibian conservation, as well as for the welfare of captive amphibians in general. Our data lend support for the provision of UVB radiation for captive, basking amphibians.     

UV‐light and dietary vitamin D and their effects on ionized calcium and 25‐OH‐D plasma concentrations in captive gentoo penguins (Pygoscelis papua)

In this study, the effect of ultraviolet (UV) light and dietary vitamin D on calcium metabolism in permanently indoor‐housed gentoo penguins (Pygoscelis papua ) was investigated. The study consisted of three periods, each completed with blood samples to analyse plasma concentrations of 25‐OH‐D, 1,25‐(OH)₂‐D, ionized (iCa) and total calcium (tCa). During the first study period (D), animals were housed under routine conditions without UV‐light and fed a diet of different fish species, supplemented with 1,000 IU vitamin D per animal and day. The following study period (Baseline) of 28‐day duration consisted of the same diet without any vitamin D supplementation and without UV‐light. During the study period (UVB) artificial UV‐light was added for 3 weeks. The vitamin D content of fish was measured by high‐performance liquid chromatography. It varied between fish species and between facilities, ranging from no measurable content in capelin (Mallotus villosus ) to 7,340 IU vitamin D/kg original matter (OM) in herring (Clupea spp). The average dietary vitamin D content was 311 IU/kg OM at facility 1 and 6,325 IU/kg OM at facility 2, resulting in a vitamin D intake per animal and day without supplementation of 130 IU (25.5 IU/kg body weight BW) and 2,454 IU (438.2 IU/kg BW) respectively. The supplementation of vitamin D elevated significantly the plasma concentrations of 25‐OH‐D by an intraindividual difference of 15 (range ?2 to 59) nmol/L and tCa by 0.1 (0.0–0.3) mmol/L only at facility 2. The exposure to UV‐light raised the blood concentrations of tCa at facility 2 by 0.15 (0.1–0.2) mmol/L, and of iCa and tCa for females at facility 1 by 0.23 (0.13–0.41) mmol/L and 1.8 (1.1–2.5) mmol/L respectively. No significant influence of the study periods (D) and (UVB) was found for the concentrations of 1,25‐(OH)₂‐D at both facilities.     

Thyroid hormones and metabolic rate during induction of Vitamin B12 deficiency in goats

Vitamin B₁₂ deficiency was induced in 15 small East African goats by feeding cobalt deficient ^{Chloris guyana} hay (containing 0.02 mg of Co/kg dry matter) over a 25week experimental period. Cobalt was supplemented as an oral drench to supply 0.3 g of Co/goat/week to 15 treated goats. At intervals of 3–4 weeks, serum concentrations of Vitamin B₁₂ total thyroxine (TT₄), free tetra-iodothyronine (FT₄) and free tri-iodothyronine (FT₃) were determined by radioimmunoassay, while the rate of resting metabolism was determined by measuring the goats' rate of oxygen consumption.

Serum Vitamin B₁₂ concentration was significantly higher (p<0.01) in cobalt-treated (289.6 ± 40.76 pg/ml) than in control (142.8 ± 28.27 pg/ml) goats. The mean serum TT₄ concentration was signifieantly (p<0.01) higher in control (59.0 ± 1.70 nmol/l) than in cobalt-treated (51.6 ± 2.45 nmol/l) goats. However, the levels of FT₄, FT₃ and the rate of resting metabolism were unaffected by the goats' cobalt status. Furthermore, the goats did not lose weight or become anaemic.     

DIETARY VITAMIN D3 INFLUENCE ON SERUM 25-HYDROXY VITAMIN D CONCENTRATIONS IN CAPTIVE SUGAR GLIDERS (PETAURUS BREVICEPS)

A pilot study was performed to investigate the impact of dietary vitamin D on circulating 25-hydroxyvitamin D (25[OH]D) metabolite concentrations in sugar gliders (Petaurus breviceps). The study with diets containing 0, 0.2 (low), or 0.4 (moderate) International Units vitamin D₃ per gram of dry matter and fed to adults at 2 locations. Serum 25[OH]D concentrations did not differ between animals fed produce only (no added vitamin D–either D₂ or D₃) for 3 weeks (8.83 ± 0.98 nmol/L), n?=?6, or low dietary levels (7.86 ± 3.80 nmol/L), n?=?7, continuously for multiple years. Conversely, animals consuming diets containing moderate vitamin D₃ levels displayed increased circulating concentrations (15.00 ± 3.59), n?=?8, after 3 weeks. Despite the response to diets supplemented with vitamin D, overall metabolite levels were low and may indicate minimal metabolic dependence on this nutrient in sugar gliders, similar to processes documented in other hindgut fermenters.     

Effect of biotin supplementation on the vLa4 of thoroughbred horses

Thoroughbred horses in racing condition were supplemented twice daily with 25 mg biotin (biotin group), while control horses received an equivalent amount of maltodextrose as a placebo (placebo group). Changes of v_fLa4 (running speed necessary for producing a lactate concentration of 4 mmol/l in the blood) were determined with an incremental step test within three days and after two, three and four months after the beginning of supplementation. The mean v_fLa4 of both the biotin and the placebo groups (5 horses each) did not change significantly within three days of supplementation, but the mean plasma biotin concentration increased in the biotin group from 1.3±0.4 to 47±22 nmol/l (p<0.01), while remaining below 3 nmol/1 in the placebo group. There was no significantly different development of the v_fLa4 between groups over four months of supplementation. But, while the mean v_fLa4 of Thoroughbreds supplemented with biotin over this period of time did not show any changes, the v_fLa4 of the placebo group horses showed a tendency to decrease. In the biotin group, the mean plasma biotin levels varied between 38 and 64 nmol/l over the four months, while the biotin concentration of the placebo group never exceeded 3 nmol/1.     

Effects of 25‐hydroxycholecalciferol supplementation in maternal diets on milk quality and serum bone status markers of sows and bone quality of piglets

Twenty primiparous sows were allocated to two treatments to evaluate the effects of maternal 25‐hydroxycholecalciferol (25OHD₃) supplementation during gestation and lactation on milk quality and serum bone status markers of sows and bone quality of piglets. Immediately after mating, sows were randomly allotted to one of two diets supplemented with 50 µg/kg 25OHD₃ or basal diets without 25OHD₃. Blood and milk samples were obtained. At birth and weaning, 10 piglets from each treatment were killed for bone quality analysis. 25OHD₃‐fed sows provided one more piglet at farrowing and 1.17 more piglets at weaning than sows fed basal diets. The contents of solids not‐fat, protein, fat or lactose were increased in milk from days 7 and 14 of lactation in 25OHD₃‐supplemented sows and 25OHD₃ concentrations in milk were increased by dietary 25OHD₃ supplementation. Dietary 25OHD₃ supplementation increased serum alkaline phosphatase activity but had no effect on serum tartrate‐resistant acid phosphatase activity of sows. Maternal 25OHD₃ supplementation improved bone strength, density and ash content of newborn piglets rather than those of weaning piglets. In conclusion, 25OHD₃ supplementation in maternal diets improved reproductive performance, milk quality and bone status of sows as well as bone quality of newborn piglets.     

Combined GnRH and PGF2α Application in Cows with Endometritis Puerperalis Treated with Antibiotics

The investigations were carried out on a total of 70 cows with puerperal endometritis. In addition to intrauterine antibiotic treatment, 30 experimental animals were administered 20 μg GnRH analogue, buserelin, between days 10 and 12 post‐partum followed by 500 μg PGF_2α analogue, cloprostenol, 10 days later. Forty control cows were treated only with intrauterine antibiotics. Blood samples for progesterone determination were collected from the tail vein twice weekly until day 70 post‐partum. The first rise in progesterone level above 3.18 nmol/l occurred significantly earlier in the experimental than in control cows (21.6 ± 9.2 versus 27.8 ± 12.3 days; p ≤ 0.05). The duration of the first cycle post‐partum was 15.0 ± 4.3 days in experimental and 19.7 ± 7.3 days in control animals (p ≤ 0.05). However, no significant differences were observed in the occurrence of first oestrus post‐partum. The involution of the uterus was improved after hormone treatment. At day 42 post‐partum, completion of uterine involution was found in 93.3% of hormone‐treated cows and in 82.5% of those treated with antibiotic only (p ≤ 0.05). Clinical recovery was 96.6% in the experimental and 82.5% in the control group (p ≤ 0.05). First service pregnancy rate was significantly better in hormone‐treated than control cows (51.7 versus 36.4%; p ≤ 0.05). Total pregnancy rate and insemination index values were not significantly improved following GnRH and PGF_2α treatment. The average service period was 89.8 ± 21.2 days in cows after hormone treatment, and 112.6 ± 24.5 days in control cows. The difference was statistically significant (p ≤ 0.05). These results indicate, that the sequential GnRH and PGF_2α application in cows with puerperal endometritis positively affected ovarian function and uterine involution, resulting in improved fertility performance.     

Effects of ultraviolet radiation on plasma 25-hydroxyvitamin D3 concentrations in corn snakes (Elaphe guttata)

OBJECTIVE: To determine whether corn snakes exposed to UVB radiation have increased plasma 25-hydroxyvitamin D3 concentrations, compared with control snakes. ANIMALS: 12 corn snakes (Elaphe guttata). PROCEDURES: After an acclimation period in individual enclosures, a blood sample was collected from each snake for assessment of plasma 25-hydroxyvitamin D3 concentration. Six snakes were provided with no supplemental lighting, and 6 snakes were exposed to light from 2 full-spectrum coil bulbs. By use of a radiometer-photometer, the UVA and UVB radiation generated by the bulbs were measured in each light-treated enclosure at 3 positions at the basking surface and at 2.54 cm (1 inch) below each bulb surface; the arithmetic mean values for the 3 positions at the basking surface and each individual bulb surface were calculated immediately after the start of the study and at weekly intervals thereafter. At the end of the study (day 28), another blood sample was collected from each snake to determine plasma 25-hydroxyvitamin D3 concentration. RESULTS: Mean +/- SD plasma concentration of 25-hydroxyvitamin D3 in snakes that were provided with supplemental lighting (196 +/- 16.73 nmol/L) differed significantly from the value in control snakes (57.17 +/- 15.28 nmol/L). Mean exposure to UVA or UVB did not alter during the 4-week study period, although the amount of UVA recorded near the bulb surfaces did change significantly. CLINICAL RELEVANCE: These findings have provided important insight into the appropriate UV radiation requirements for corn snakes. Further investigation will be needed before exact husbandry requirements can be determined.     

Effect of grazing pasture with a low selenium content on the concentrations of triiodothyronine and thyroxine in serum,and GSH-Px activity in erythrocytes in cows in Chile

AIM: To determine the effect of grazing pasture that had a low selenium (Se) concentration on serum concentrations of tri iodothyronine (T₃) and thyroxine (T₄), and erythrocyte glutathione peroxidase (GSH-Px) activity in dairy cows.

METHODS: Forty pregnant Friesian cows were grazed on pasture that contained 0.03–0.04 ppm Se on a dry matter (DM) basis. Two months before parturition, 20 cows were randomly selected and treated with 1 mg Se/kg bodyweight subcutaneously, as barium selenate (Group Se-S). The other group (Se-D) was not supplemented. Blood samples were taken before supplementation (-60 days) and 30, 60, 90, 180 and 270 days after parturition, for determination of concentrations of T₃ and T₄ in serum, and GSH-Px activity in erythrocytes.

RESULTS: Erythrocyte GSH-Px activity in the Se-D group was >60 U/g haemoglobin (Hb) throughout the experiment. Supplementation increased (p>0.05) activities to >130 U/g Hb throughout lactation. Mean serum concentrations of T₄ in Se-D and Se-S cows increased from 23.7 (SEM 0.7) and 23.4 (SEM 0.8) nmol/L, respectively, in the prepartum period to 69.6 (SEM 0.1) and 67.6 (SEM 0.2) nmol/L, respectively, at 180 days of lactation (p>0.01), and no effect of Se supplementation was evident. Serum concentrations of T₃ in Se-D cows decreased (p>0.05) from 1.6 (SEM 0.1) nmol/L prepartum to 1.0 (SEM 0.2) nmol/L at the beginning of lactation, and remained lower (p>0.05) than those in the Se-S cows which did not decrease after calving and ranged from 1.9 (SEM 0.1) to 2.4 (SEM 0.2) nmol/L throughout lactation.

CONCLUSIONS: Serum T₃ concentrations decreased during early lactation in unsupplemented cows grazing pastures low in Se (0.03–0.04 ppm) and both serum T₃ and erythrocyte GSH-Px activities were consistently lower throughout lactation compared with Se-supplemented cows. Se supplementation had no effect on serum T₄ concentrations.     

A comparison of UVb compact lamps in enabling cutaneous vitamin D synthesis in growing bearded dragons

The effect of exposure to different UVb compact lamps on the vitamin D status of growing bearded dragons (Pogona vitticeps) was studied. Forty‐two newly hatched bearded dragons (<24 h old) were allocated to six treatment groups (n = 7 per group). Five groups were exposed to different UVb compact lamps for two hours per day, with a control group not exposed to UVb radiation. At 120 days of age, blood samples were obtained and concentrations of 25(OH)D₃, Ca, P and uric acid were determined. In addition, plasma 25(OH)D₃ concentration was determined in free‐living adult bearded dragons to provide a reference level. Only one treatment resulted in elevated levels of 25(OH)D₃ compared to the control group (41.0 ± 12.85 vs. 2.0 ± 0.0 nmol/L). All UVb‐exposed groups had low 25(OH)D₃ plasma levels compared to earlier studies on captive bearded dragons as well as in comparison with the free‐living adult bearded dragons (409 ± 56 nmol/L). Spectral analysis indicated that all treatment lamps emitted UVb wavelengths effective for some cutaneous vitamin D synthesis. None of these lamps, under this regime, appeared to have provided a sufficient UVb dose to enable synthesis of plasma 25(OH)D₃ levels similar to those of free‐living bearded dragons in their native habitat.     

Twenty-four-hour Profiles of Serum Prolactin and Luteinizing Hormone in Anoestrous Crossbred Bitches

The dynamics of prolactin (PRL) and luteinizing hormone (LH) secretion in the anoestrous bitch is poorly known. Therefore, the objective of this study was to characterize the 24 h profiles of serum PRL and LH in crossbred anoestrous bitches and to assess whether a relationship exists between the secretory patterns of these two hormones. Serum PRL and LH concentrations were measured in 10 healthy anoestrous crossbred bitches at 145 min intervals for 24 h. During the experiment the animals received continuous artificial illumination and remained undisturbed except at the time of blood sampling. Serum PRL was measured by a homologous enzyme‐linked immunosorbent assay, whereas LH and progesterone (P₄) were determined by radioimmunoassay. The anoestrous state of the bitches was assessed by vaginal cytology, vaginoscopy and physical examination. Two groups of animals were identified according to their PRL levels: a high PRL group (n=3, mean ± SEM 12.3 ± 2.7 ng/ml) and a low PRL group (n=7, mean ± SEM: 2.5 ± 0.9 ng/ml). In the low PRL group, the PRL profiles were flat and did not show any significant circadian pattern. Nevertheless, occasional single‐point peaks were detected in some of the bitches. In the high PRL group the individual PRL profiles were variable. To detect the presence of a circadian change of PRL concentrations, two different sets of time windows (TW) of sampling were studied. The first set was: day [TW1A, samples 1–5 (0900–1840 h)] and night [TW1B, samples 6–10 (2105–0645 h)]. The second set was chosen after visual inspection of the average PRL profiles for both (high and low) groups: [TW2A, samples 3–7 (1350–2330 h) and TW2B, samples 1–2 and 8–10 (0155–1125 h)]. PRL concentrations were not significantly different between day and night. In the high PRL group, but not in the low PRL group, average serum PRL was significantly (p < 0.01) higher in TW2A than TW2B. In both groups serum LH levels were more homogeneous than PRL levels. Neither TW showed circadian changes in LH patterns of secretion (TW1A versus TW1B, p < 0.69; TW2A versus TW2B, p < 0.88). On the other hand, bitches in the high PRL group showed significantly (p < 0.01) lower serum LH levels than those in the low PRL group of animals. Serum PRL concentrations presented a significant inverse correlation with LH concentrations (r=?0.21, p < 0.03) and a significant positive correlation with P₄ concentrations across the study (0.92, p < 0.01). It is concluded that in anoestrous crossbred bitches serum PRL is highly variable and inversely related to LH. No circadian rhythm of PRL secretion appears to exist in most anoestrous bitches.     

Comparison between blood serum and salivary cortisol concentrations in horses using an adrenocorticotropic hormone challenge

Reasons for performing study: In horses, serum cortisol concentration is considered to provide an indirect measurement of stress. However, it includes both free and bound fractions. The sampling method is also invasive and often stressful. This is not the case for salivary cortisol, which is collected using a more welfare‐friendly method and represents a part of the free cortisol fraction, which is the biologically active form. Objectives: To compare salivary and serum cortisol assays in horses, in a wide range of concentrations, using an adrenocorticotropic hormone (ACTH) stimulation test, in order to validate salivary cortisol for stress assessment in horse. Methods: In 5 horses, blood samples were drawn using an i.v. catheter. Saliva samples were taken using swabs. Cortisol was assayed by radioimmunoassay. All data were treated with a regression method, which pools and analyses data from multiple subjects for linear analysis. Results: Mean ± s.d. cortisol concentrations measured at rest were 188.81 ± 51.46 nmol/l in serum and 1.19 ± 0.54 nmol/l in saliva. They started increasing immediately after ACTH injection and peaks were reached after 96 ± 16.7 min in serum (356.98 ± 55.29 nmol/l) and after 124 ± 8.9 min in saliva (21.79 ± 7.74 nmol/l, P<0.05). Discharge percentages were also different (225% in serum and 2150% in saliva, P<0.05). Correlation between serum and salivary cortisol concentrations showed an adjusted r²= 0.80 (P<0.001). The strong link between serum and salivary cortisol concentrations was also estimated by a regression analysis. Conclusions: The reliability of both RIAs and regression found between serum and salivary cortisol concentrations permits the validation of saliva‐sampling as a noninvasive technique for cortisol level assessment in horses.     

Gentamicin pharmacokinetics in newborn and 42-day-old male piglets

The pharmacokinetics of gentamicin was investigated in six newborn male piglets, aged from 4 to 12 h at the time of administration of the drug, and six 42-day-old castrated male piglets, that had been weaned for 2 weeks following a single intravenous bolus of 5 mg/kg. Gentamicin was measured in serum and in urine by a fluorescence polarization immunoassay. The serum concentrationtime data were best described by a three-compartment open model. A rapid initial distribution phase (± phase) was observed in every animal. The serum β half-life (t_1/2β) was significantly longer in the newborn piglets (mean ± SEM) (5.19 ± 0.30 h) than in the older group (3.50 ± 0.23 h) (P < 0.05). Mean residence time was similarly longer in younger piglets (6.62 ± 0.57 h) than in older animals (2.86 ± 0.11 h) (P < 0.05). The steady-state volume of distribution (V_ills was significantly larger for younger pigs (0.785 ± 0.036 L/kg) than in elder pigs (0.474 ± 0.029 L/kg) (P < 0.05). Urinary γ half-life (t_1/27u) was 72.66 ± 10.78 h in the newborn piglets and 69.20 ± 14.77 h in the 42-day-old animals. A urinary δ phase was observed in three of the 42-day-old piglets and gave a mean (t_1/2δu of 232.01 ± 14.55 h. Percentages of urinary recovery of the administered dose after 144 h were 94.18 ± 1.01 and 94.04 ± 1.12 in the newborn and 42-day-old animals, respectively. Serum gentamicin clearance was significantly lower in younger animals (0.121 ± 0.007 L/h±kg) than in the 42-day-old group (0.166 ± 0.010 L/h·kg). It is suggested that in the newborn piglets, the increase of V_d(ss) could be explained by a higher proportion of extracellular water while the lower clearance could be attributed to a reduced glomerular filtration capacity. Gentamicin dosage requirement in the newborn piglets would therefore have to be adjusted, in order to take into consideration the observed differences in the mean values of these latter pharmacokinetic parameters.     

Effects of 25‐hydroxy‐cholecalciferol on the development of osteochondrosis in swine

The principal objective of this experiment was to evaluate the effect of 25‐hydroxy‐cholecalciferol (25‐OH‐D₃) on the development of osteochondrosis in 6‐ to 110‐kg castrated male pigs. The growth rate and serum calcium and inorganic phosphate levels neither increased nor decreased in response to supplementation of 25‐OH‐D₃. However, supplemental 25‐OH‐D₃ significantly increased serum levels of 25‐OH‐D₃ and 1α,25‐hydroxy‐cholecalciferol without any influence on bone mineral density. The 25‐OH‐D₃‐treated group had significant (P < 0.05) reduced incidence of osteochondrotic lesions compared to the control group as evidenced by macroscopically examining the articular cartilage of the distal humerus (32.4% vs. 59.3%) and distal femur (47.1% vs. 87.5%). Likewise, supplemental 25‐OH‐D₃ significantly reduced osteochondrotic lesions over the control when histologically examining humerus (20.6% vs. 43.8%) and femur (52.9% vs. 87.5%). The results of this experiment suggested that 25‐OH‐D₃ supplementation in pig diets had a tendency to promote normal endochondral ossification, inhibit osteochondrosis progression and possibly regenerate destroyed cartilage tissue.     

Estrus induction in anestrous mixed-breed goats using the “female-to-female effect”

A trial was conducted during the anestrous period in female goats to determine: (a) whether estrus can be induced in anestrous goats by administration of equine chorionic gonadotropic hormone (eCG) and PGF_2α under pen conditions and (b) whether these sexually active female goats can elicit sexual arousal in sexually inactive bucks. One hundred and fifteen pluriparous, nonlactating mixed-breed female goats were randomly assigned to one of four treatment groups: (1) administration of a single dose of 240 IU of eCG, 50 μg PGF_2α i.m., and 25 mg progesterone (P₄) (eCG; n?=?30); (2) administration of P₄ and exposure to female goats treated with eCG–PGF_2α (P₄; n?=?39); (3) administration of 0.5 ml saline and P₄ (Sal; n?=?23); and (4) P₄ plus exposure to female goats treated with saline (Con; n?=?23). After hormone administration, all goats were put together with adult sexually inactive bucks for 15 days. The percentage of goats in estrus during these 15 days was similar in eCG-treated animals and untreated animals exposed to the eCG animals (97 and 95 %). Pregnancy rate was also similar (63 vs. 64 %) between these two groups. eCG-treated goats exhibited estrus earlier (P?<?0.05) than the treated goats in contact with the eCG goats. Furthermore, eCG-treated goats had larger litters (1.9?±?0.2 vs. 1.6?±?0.1, P?<?0.05) than the untreated goats in contact with the eCG goats. These results show that fertile estrus can be induced in anestrous female goats by exposing them to female goats induced to estrus with eCG. This female–female interaction triggers the stimulation cycle leading to the sexual arousal of bucks.     

Free-range system and supplementation of 25-hydroxicholecalciferol increases the performance and serum vitamin levels in mixed-parity sows

Improvements in sow productivity have raised questions regarding dietary vitamin D recommendations. The present study aimed to evaluate the effects of the housing system with access to sunlight exposure and supplementation of 25-hydroxicholecalciferol on performance and serum levels of 25(OH)D₃ in sows during gestation and lactation. Sows were distributed in an experimental design with two housing systems: gestation crates or gestation free-range system with external area for sunlight exposure; and two diets: 0 or 50 μg of 25-hydroxicholecalciferol kg⁻¹. The use of 25-hydroxicholecalciferol tended (P = 0.052) to improve total born and influenced (P = 0.046) on number of born alive. Litter weight at birth was also increased (P = 0.01) by 25-hydroxicholecalciferol supplementation; 25-hydroxicholecalciferol supplementation and housing system (free-range with sunlight exposure) tended to increase weaning weight (P = 0.07) and litter daily gain (P = 0.051) during lactation. Exposure to sunlight and 25-hydroxicholecalciferol supplementation increased 25(OH)D₃ serum levels when compared with control treatment during gestation (136.95 vs. 113.92 ng mL⁻¹; P = 0.035) and lactation (120.29 vs. 88.93 ng mL⁻¹; P = 0.026). In conclusion, the association of 25-hydroxicholecalciferol supplementation with exposure to sunlight during gestation improved significantly 25(OH)D₃ serum levels and consequently performance traits in gestation and lactation.     

Effect of supplementation with corn oil on postpartum ovarian activity,pregnancy rate,and serum concentration of progesterone and lipid metabolites in F<Subscript>1</Subscript> (<Emphasis Type="Italic">Bos taurus</Emphasis> × <Emphasis Type="Italic">Bos indicus</Emphasis>) cows

The aim was to evaluate the effect of corn oil supplementation during postpartum anoestrus on ovarian activity, pregnancy rate, progesterone (P₄), and lipid metabolites (cholesterol, CHO; low and high density lipoproteins; LDL and HDL, respectively) concentrations in blood of F₁ (Bos taurus × Bos indicus) grazing cows. Cows were randomly assigned to an experimental group, fed with a supplement containing 4% corn oil on dry matter basis (OG, n = 11), and a control group with the same supplement without corn oil (CG, n = 12). Both supplements contained equivalent amounts of crude protein and metabolizable energy and were fed for 34 days continuously. All cows were induced to estrous 12 days after beginning of supplementation by using a synthetic progestagen and artificially inseminated 56 h after retiring the implants. Pregnancy diagnosis was performed by transrectal palpation 45 days after insemination, evaluating simultaneously ovarian activity. P₄ and lipid metabolites (CHO, HDL, LDL) concentrations were determined in blood samples collected at 3-day intervals, from the beginning of corn oil supplementation and up to 10 days after artificial insemination. Ovarian activity was affected by treatment (p < 0.05), finding ovarian structures in 72.7% of OG cows and in 50% of CG cows. Concentration of P₄ and CHO was higher for OG with respect to CG (2.52 ± 0.65 vs 1.88 ± 0.62 ng/ml and 117.79 ± 11.57 vs 85.71 ± 12.11 mg/dl, respectively), whereas pregnancy rate and blood concentrations of HDL and LDL were not affected by treatment (p > 0.05). Addition of corn oil to the supplement stimulated ovarian activity and increased serum concentrations of progesterone and cholesterol in grazing B. taurus × B. indicus cows with low body condition score showing postpartum anoestrus.     

Effect of diet on serum 25-hydroxyvitamin D concentration in the short-beaked echidna (Tachyglossus aculeatus)

Background Elevated concentrations of 25‐hydroxyvitamin D (25(OH)‐D) were diagnosed in captive short‐beaked echidnas (Tachyglossus aculeatus) from three different zoological facilities within Australia. Results The mean serum 25(OH)‐D concentration in the wild echidnas was 24.7 nmol/L and was significantly higher in captive echidnas from all three facilities: Facility 1, mean 335.5 nmol/L (P < 0.001); Facility 2, mean 187.2 nmol/L (P = 0.003); Facility 3, mean 194 nmol/L (P = 0.005). Animals did not appear to have clinical manifestations of vitamin D toxicosis. The increased serum 25(OH)‐D concentration was attributed to excessive dietary intake and a reduction in the amount of vitamin D₃ in the diet of echidnas from Facility 1 resulted in a marked decrease in the serum 25(OH)‐D concentrations (mean 33 nmol/L). The reduction in serum 25(OH)‐D concentration was statistically significant (P = 0.002) and the resulting concentrations were similar to those of wild echidnas (P = 0.212). Conclusion It is not known what effect an elevated serum 25(OH)‐D concentration has on echidnas.