Effects of 25(OH)D3 supplementation during late gestation on the serum biochemistry and reproductive performance of aged sows and newborn piglets

The purpose of this study was to investigate the effects of diet type (normal or low Ca and P diets) and 25(OH)D₃ supplementation (with or with not 2000 IU/kg 25(OH)D₃) during late gestation on the serum biochemistry and reproductive performance of aged sows and newborn piglets. A total of 40 sows, which are at their 7th parity, were divided into four groups: control group (standard diet), low Ca group, 25(OH)D₃ group and low Ca plus 25(OH)D₃ group respectively (10 in each group). The blood of sows on day 100 and 114 of gestation and newborn piglets was collected for serum biochemical analyses. Results showed that the reproductive performance of sows was not influenced by diet type or 25(OH)D₃ supplementation (p > 0.05). And the addition of 25(OH)D₃ to diet low Ca group caused that the content of serum TG in sows on day 100 of gestation was not different from that of the control group (p > 0.05). The addition of 25(OH)D₃ significantly decreases the content of serum TG in sows on day 114 of gestation (p < 0.05). The addition of 25(OH)D₃ significantly increased the content of serum UREA and CREA in newborn piglets (p < 0.05). Overall, feeding 2000 IU/kg 25(OH)D₃ to aged sows at late gestation had no effects on reproductive performance, but partly contributed to keeping serum TG balance in sows and may indicate increased pressure on kidneys in newborn piglets.     

Serum 25‐hydroxyvitamin D concentrations in dogs – correlation with health and cancer risk

25‐hydroxyvitamin D (25(OH)D) is important in bone health as well as many diseases including cancer. Supplementation may increase responsiveness of cancer cells to chemotherapy. Serum 25(OH)D, intact parathyroid hormone (iPTH) and canine C‐reactive protein (c‐CRP) were measured in healthy dogs and dogs with haemoabdomen. Regression analysis determined optimal 25(OH)D concentrations. In healthy dogs (n = 282), mean iPTH concentrations correlated inversely (r² = 0.88, P < 0.001) to 25(OH)D concentrations. Variation in both iPTH and c‐CRP plateaued at 25(OH)D concentrations of 100–120 ng mL^?1. Haemoabdomen dogs (n = 63, 43 malignant and 20 benign) had 25(OH)D concentrations ranging from 19.4 to >150 ng mL^?1. Relative risk of cancer increased with decreasing 25(OH)D concentrations [RR = 3.9 for 25(OH)D below 40 ng mL^?1 (P = 0.0001)]. Serum 25(OH)D concentrations in dogs vary widely, and are influenced by dietary VitD content. Serum vitD measurement can identify dogs for which supplementation may improve health and response to cancer therapy.     

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.     

The effect of dietary vitamin D supplementation on sodium-dependent phosphate uptake and expression of NaPi-IIb in the small intestine of weanling pigs

Two experiments were conducted to investigate the effects of 1,25(OH)₂D₃ to stimulate Na⁺-dependent phosphate uptake in Caco-2 cells, and the effects of dietary vitamin D supplementation to vitamin D-deficient nursery pigs on Na⁺-dependent nutrient uptake and mRNA expression of NaPi-IIb cotransporter and calbindin D9k in the jejunum. In Exp. 1, 250,000 Caco-2 cells were seeded on Costar 12 mm Snapwell inserts with a 0.40 µm polycarbonate filter and a seeding density of 0.25 × 10⁶ and studied at 15 d postconfluence. Cells were treated with 10 nM of either 1,25(OH)₂D₃ or vehicle for 48 h and then mounted in modified Ussing chambers for transepithelial measurements. In Exp. 2, pigs (n = 32) were removed from sows at 3 d of age, placed on a vitamin D-deficient milk replacer diet and housed in a room devoid of sunlight and UV light in the range of 280 to 300 nm. On day 28, serum 25(OH)D₃ concentrations were measured to verify low vitamin D status. Pigs (BW 10.10 ± 0.38 kg) were then individually housed day 28 postweaning and allotted to 1 of 2 dietary treatments. Dietary treatments consisted of corn-soybean-based diets with vitamin D supplementations of 0 or 1,500 IU/kg diet for 12 d. Blood samples were taken from the brachiocephalic vein on the initial (day 0) and final day (day 10, 11, or 12) of the study for analysis of serum 25(OH)D₃, P, and Ca. Pigs were euthanized and jejunal segments were harvested and used in modified Ussing chambers and for RNA isolation and subsequent quantitative RT-PCR analysis. In Exp. 1, treating Caco-2 cells with 10 nM 1,25(OH)₂D₃ resulted in a 52% increase (P < 0.005) in Na⁺-dependent phosphate uptake compared with cells treated with a vehicle. In Exp. 2, Na⁺-dependent phosphate and glucose transport did not differ (P > 0.10) among treatment groups. Additionally, NaPi-IIb and calbindin D9k mRNA expression were not different (P > 0.10) between treatment groups. No differences (P > 0.10) were detected in final serum P or 25(OH)D₃ concentrations between treatments. However, serum Ca linearly increased (P < 0.05) as the concentration of supplemental vitamin D increased in the diet. Overall, while 1,25(OH)₂D₃ stimulated Na⁺-dependent phosphate uptake in Caco-2 cells, supplementing diets with 1,500 IU/kg vitamin D₃ from cholecalciferol did not increase jejunal Na⁺-dependent phosphate uptake or NaPi-IIb mRNA expression over that of pigs fed diets with no supplemental cholecalciferol.     

Effects of 25‐hydroxycholecalciferol with two D3 vitamin levels on production and immunity parameters in broiler chickens

This study was performed in Ross 308 chickens aged 1–21 days and aimed to evaluate whether the addition of 25‐hydroxycholecalciferol (25(OH)D₃) to broiler chicken diets affects their growth performance and immunity. A completely random 2 × 2 factorial arrangement was used with two levels of vitamin D₃ and the absence or presence of 25(OH)D₃, corresponding to four treatments based on sorghum + soya bean diets: (i) 200 IU of vitamin D₃/kg of feed (Diet 1) (NRC, 1994 ), (ii) Diet 1 + 69 μg of 25(OH)D₃/kg of feed (Diet 2), (iii) 5,000 IU of vitamin D₃/kg of feed (Diet 3) and (iv) Diet 3 + 69 μg of 25(OH)D₃/kg of feed (Diet 4). Each treatment was conducted with six replicates of 10 chickens each. Water and feed was supplied ad libitum. The results showed significantly increased growth and tibia ash (p < .05) in the birds fed 5,000, IU of vitamin D₃/kg + 25(OH)D₃. Additionally, the cellular immune response increased significantly (p < .05) in both treatments with added 25(OH)D_3. Based on the results obtained under the current test conditions, the addition of 25(OH)D₃ at a rate of 69 μg/kg to diets containing vitamin D₃ improved the cellular immune response and mineral deposition in the bones of broilers aged 1–21 days. Because these parameters are very important in modern poultry farming, these results indicate that supplementation with 25(OH)D₃ should improve broiler production.     

Effect of maternal canthaxanthin and 25‐hydroxycholecalciferol supplementation on the performance of ducklings under two different vitamin regimens

This study investigated the effects of maternal canthaxanthin (CX, 6 mg/kg) and 25‐hydroxycholecalciferol (25‐OH‐D₃, 0.069 mg/kg) supplementation on the performance of Cherry Valley ducklings under two different vitamin regimens. A total of 780 duck breeder females and 156 males were randomly allotted to two diets with or without the addition of the mixture of CX and 25‐OH‐D₃ (CX+25‐OH‐D₃) for 32 weeks. Ducklings (males and females separately) hatched from eggs laid at 24 weeks of the duck breeder trial were fed with a NRC vitamin regimen, and ducklings (males and females separately) hatched from eggs laid at 32 weeks of the duck breeder trial were fed with a HIGH vitamin regimen (had higher levels of all vitamins except biotin than NRC vitamin regimen), for 14 days. The results showed that, maternal CX+25‐OH‐D₃ supplementation increased the shank pigmentation for 7‐days post hatch in ducklings under a NRC vitamin regimen, and for 14‐days post hatch in ducklings under a HIGH vitamin regimen. Growth performance, antioxidant status and serum phosphorus of ducklings under a NRC vitamin regimen were increased by maternal CX+25‐OH‐D₃ supplementation; however, these positive effects were not observed in ducklings under a HIGH vitamin regimen. Males revealed increased growth performance in ducklings under both NRC and HIGH vitamin regimens. Sexual differences in shank pigmentation, antioxidant status, tibia strength and serum phosphorus were not consistent as they were dependent on maternal CX+25‐OH‐D₃ status or dietary vitamin regimens. Data suggest that maternal CX+25‐OH‐D₃ supplementation is important for starter ducklings under a NRC vitamin regimen, but not HIGH vitamin regimen.     

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 25‐hydroxycholecalciferol supplementation in maternal diets on reproductive performance and the expression of genes that regulate lactation in sows

One hundred Yorkshire × Landrace sows were randomly assigned to one of two dietary treatments (diet ND: 6,000 IU vitamin D₃/d feed; diet 25‐D: 200 μg/day 25OHD₃ feed). The experiment began on d 90 of gestation and continued until weaning on day 21 of lactation. In sows that received 25OHD₃, the growth rate of the piglets before weaning was significantly accelerated (0.266 kg/day, p < .05). Sow serum was collected after weaning, and those in the 25OHD₃ group were found to have significantly higher serum calcium (CA) and phosphorus (PI) levels (p < .05). Interestingly, the oestrus cycle of sows fed 25OHD₃ was significantly shortened (p < .05), the oestrus time was concentrated on the fifth day after weaning, and the piglets were born with a higher degree of uniformity (p < .05). Colostrum was collected on the day of delivery, and the colostrum of sows fed 25OHD₃ contained higher milk fat content than the control group (p < .05). 25OHD₃ supplementation increased the mRNA and protein expression of INSIG1 and SREBP1, which regulate milk fat synthesis, in the mammary gland of lactating sows (p < .05). In conclusion, 25OHD₃ supplementation in maternal diets improved reproductive performance, milk fat content and the mRNA and protein levels of genes regulating milk fat synthesis in lactating sows.     

Effects of different gestation housing types on reproductive performance of sows

This study evaluated the effects of different gestation housing types on reproductive performance of sows. A total of 60 sows (218 ± 24 kg body weight) with mixed parity were used. During gestation, 28 sows were housed in groups with electronic sow feeders (space allowance = 1.26 m²/sow) and 32 sows were housed in individual stalls (space allowance = 1.20 m²/sow). Sows from both housing types were moved to farrowing crates on day 109 of gestation and stayed until weaning (18 days post‐farrowing). Typical corn‐soybean meal diets were provided to sows during gestation and lactation. Measurements were reproductive performance of sows at farrowing as well as performance of sows and their litter during lactation. Similar total numbers of piglets born at farrowing were observed for sows gestated in both housing types. However, group‐housed gestation sows had more mummies (0.321 vs. 0.064; P < 0.05) and stillbirths (0.893 vs. 0.469; P = 0.073) at farrowing than individual‐housed gestation sows. Consequently, individual‐housing type had higher percentage of piglets born alive (95.5 vs. 90.4%; P < 0.05) than the group‐housing type. Therefore, improved reproductive performance of sows from individual gestating housing was confirmed in this study.     

Effect of dietary supplementation of β-1,3–1,6-glucan on reproductive performance and immunity of New Zealand White does and their pups

The study was conducted to investigate the effects of dietary β-1,3–1,6-glucan supplementation on the reproductive performance and immunity of New Zealand White breeding does and their pups. Thirty pregnant multiparous New Zealand White does were randomly assigned to three dietary treatments; 0 (control), 0.064% β-1,3–1,6-glucan or 0.128% β-1,3–1,6-glucan dietary supplementation from day 14 of gestation to day 28 of lactation. The 0.128% dietary β-1,3–1,6-glucan supplementation caused reduced (P < 0.05) feed intake from day 14 to day 28 of gestation. The swelling response 24 and 48 h after injection of phytohemoagglutinin-P showed that does fed with 0.064% dietary β-1,3–1,6-glucan had lower (P < 0.05) swelling response than the control group. Serum IgG and IgM concentrations of does were significantly higher during pregnancy than during lactation. Compared to the controls, does fed with 0.128% β-1,3–1,6-glucan had reduced serum IgM concentrations at day 21 of gestation and day 3 of lactation. They had significantly reduced serum IgG at day 28 of gestation but increased serum IgG at day 3 of lactation. Serum IgM and IgG concentrations in supplemented does were higher (P < 0.05) than controls at day 28 of lactation. Both CD4⁺ and CD8⁺ T lymphocyte subsets were lowest at day 28 of gestation. There were no treatment effects on the three types of lymphocytes. Subsets of CD4⁺ in the weanling pups were higher (P < 0.05) for the 0.064% β-1,3–1,6-glucan supplementation group than the other two groups. In conclusion, dietary supplementation of β-1,3–1,6-glucan reduced feed intake during the first 14 days but had no adverse effects on the reproductive performance and body weight of does. Dietary supplementation with 0.064% β-1,3–1,6-glucan significantly inhibited delayed-type immune reaction of Th1 and significantly reduced serum IgG concentration of does at the late gestation stage but increased serum IgM and IgG concentrations at the late lactation stage.     

Dietary supplementation of Bacillus subtilis PB6 improves sow reproductive performance and reduces piglet birth intervals

We investigated the effects of dietary supplementation with Bacillus subtilis PB6 (B. subtilis PB6) during late gestation and lactation on sow reproductive performance, antioxidant indices, and gut microbiota. A total of 32 healthy Landrace × Yorkshire sows on d 90 of gestation were randomly assigned to 2 groups, with 16 replicates per group, receiving basal diet (CON) or the basal diet + 0.2% B. subtilis PB6, containing 4.0 × 10⁸ CFU/kg of feed (BS). The litter sizes (total born) and numbers of piglets born alive were larger in the BS group (P < 0.01), whereas the weights of piglets born alive and the piglet birth intervals were lower in the BS group (P < 0.05). Although the litter weights and piglet bodyweights (after cross-fostering) were lower after BS treatment (P < 0.05), the litter sizes, litter weights, lactation survival rate, and litter weight gains at weaning were higher in BS group (P < 0.05). The concentrations of malondialdehyde (MDA) in the sow sera at parturition were lower in the BS group (P < 0.01). The serum total antioxidant capacity (T-AOC) at parturition and the serum catalase (CAT) concentrations on d 21 of lactation were higher in the BS group (P < 0.05). Dietary supplementation with B. subtilis PB6 (P < 0.05) reduced the serum endotoxin concentrations in the sows and the serum cortisol concentrations of the piglets at d 14 of lactation. The α-diversity indices of microbial were higher in the CON group (P < 0.05). At the phylum level, B. subtilis PB6 supplementation increased the relative abundances of Gemmatimonadete and Acidobacteria (both P < 0.01) and reduced those of Proteobacteria, and Actinobacteria (both P < 0.05). At the genus level, B. subtilis PB6 supplementation increased the relative abundance of Ruminococcaceae_UCG-013 cc (P < 0.05) and reduced that of Streptococcus (P < 0.05). This study demonstrated that adding 4.0 × 10⁸ CFU/kg B. subtilis PB6 to sows’ feed during late gestation and lactation could shorten piglet birth intervals, enhance the growth performance of suckling piglets, and improve the gut health of sows during late gestation.     

Effect of maternal organic selenium supplementation during pregnancy on sow reproductive performance and long-term effect on their progeny

Selenium (Se) is an essential trace element for animals and exists in nature in both inorganic and organic forms. Although organic Se is more bioavailable than inorganic Se, there are inconsistent reports on the effect of organic Se on the reproductive performance of sows. This study was conducted to investigate the effect of maternal organic Se (2-hydroxy-4-methylselenobutanoic [HMSeBA]) supplementation on reproductive performance and antioxidant capacity of sows, and the long-term effect on the growth performance and antioxidant capacity of their offspring with or without lipopolysaccharide (LPS) challenge. The experimental design used in this study was a completely randomized design; 45 Landrace × Yorkshire sows were randomly allocated to receive one of the following three diets during gestation: control diet (Control, basal diet, n = 15), sodium selenite (Na₂SeO₃)-supplemented diet (Na₂SeO₃, basal diet + 0.3 mg Se/kg Na₂SeO₃, n = 15), and HMSeBA-supplemented diet (HMSeBA, basal diet + 0.3 mg Se/kg HMSeBA, n = 15). On day 21 of age, male offspring from each group were injected with LPS or saline (n = 6). As compared with the control group, maternal HMSeBA supplementation increased the number of total born piglets, while decreased birth weight (P < 0.05). In the first week of lactation, maternal HMSeBA supplementation increased litter weight gain compared with the Na₂SeO₃ group (P < 0.05) and increased the average daily gain of piglets compared with the control group and Na₂SeO₃ group (P < 0.05). Meanwhile, maternal HMSeBA supplementation decreased piglet birth interval as compared with the control group and Na₂SeO₃ group (P < 0.05). Besides, plasma glutathione peroxidase (GSH-Px) activity was higher in the HMSeBA group on farrowing 0 min and 90 min, while malondialdehyde (MDA) concentration was lower on farrowing 0, 90, and 135 min than those in the control group (P < 0.05). In addition, maternal HMSeBA supplementation increased the concentration of selenoprotein P (SELENOP) in colostrum compared with the control group (P < 0.05). Further study revealed that the LPS-challenged HMSeBA group had higher GSH-Px and total antioxidant capacity and lower MDA in weaning piglets compared with the LPS-challenged control group (P < 0.05). Taken together, maternal HMSeBA supplementation increased the number of total born piglets, shortened the duration of farrowing, improved the antioxidant capacities of sows and their offspring, and improved the growth performance of suckling pigs at the first week of lactation. Thus, HMSeBA supplementation during gestation has the potentiality to produce more kilogram of meat.     

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.     

The effect of 25‐hydroxyvitamin D3 and phytase inclusion on pig performance,bone parameters and pork quality in finisher pigs

The objective of this study was to investigate the effects of supplementing both phytase and 25‐hydroxyvitamin D₃ (25‐OH ‐D?) on pig performance, nutrient digestibility, carcass characteristics, bone parameters and pork quality in finisher pigs. The experimental design was a 2 × 2 factorial comprising of four dietary treatments. One hundred and twenty pigs (60 male, 60 female) were blocked according to live weight and sex and allocated to the following dietary treatments: low P (4.81 g/kg) diet (basal) (T1); low P diet + phytase (T2); low P diet + 25‐OH ‐D? (T3) and low P diet + phytase + 25‐OH ‐D? (T4). Pigs supplemented with phytase had a lower average daily feed intake (ADFI ) (2.45 kg vs. 2.59 kg; p  < 0.05) and lower feed conversion ratio (FCR ) (2.74 kg/kg vs. 2.85 kg/kg; p  <  0.05) compared to pigs offered the nonphytase diets. Pigs offered phytase diets had a higher (p  <  0.05) coefficient of apparent total tract digestibility (CATTD ) of ash, phosphorous (P) and calcium (Ca) compared with pigs offered the nonphytase supplemented diets. Pigs offered the 25‐OH ‐D₃ diets had a higher CATTD of N and ash. Pigs offered the phytase diets had increased (p  <  0.05) bone DM , ash, Ca, P and density compared to the nonphytase diets. There was a significant interaction (p  <  0.05) between phytase and 25‐OH ‐D₃ on cook loss. Pigs offered 25‐OH ‐D₃ had increased cook loss over the basal diet; however, there was no effect on cook loss when phytase and 25‐OH ‐D₃ were offered in combination compared to the phytase only diet. Pigs offered 25‐OH ‐D₃ exhibited higher (p  <  0.05) Warner Bratzler shear force values and lower (p  <  0.05) pork lightness (L *) surface colorimeter values. In conclusion, there was no benefit to offering a combination of phytase and 25‐OH ‐D₃ on pig performance, bone parameters or pork quality.     

EVALUATING THE CLINICAL AND PHYSIOLOGICAL EFFECTS OF LONG-TERM ULTRAVIOLET B RADIATION ON RABBITS (ORYCTOLAGUS CUNICULUS)

Vitamin D is an essential hormone in vertebrates. Most animals acquire this hormone through their diet and/or exposure to ultraviolet B (UVB) radiation. The objectives for this research were to evaluate the clinical and physiologic effects of artificial UVB light supplementation on rabbits (Oryctolagus cuniculus) and to evaluate the long-term safety of artificial UVB light supplementation over a 6-month period. Twelve New Zealand white rabbits were randomly assigned to one of two treatment groups: Group A was exposed to 12 hours of artificial UVB radiation daily and Group B received ambient fluorescent light with no UVB supplementation for 12 hours daily. All animals were offered the same diet and housed under the same conditions. Blood samples were collected every 3 weeks over 6 months to measure blood chemistry values, parathyroid hormone, ionized calcium, and serum 25-hydroxyvitamin D₃ (25-OHD₃) levels. Serial ophthalmologic examinations were performed at the beginning of the study and every 2 months thereafter. At the end of the study the animals were euthanized and necropsied. Mean ± SD serum 25-OHD₃ concentrations differed significantly (P = 0.003) between animals provided supplemental UVB radiation (83.12 ± 22.44 nmol/L) and those not provided UVB radiation (39.33 ± 26.07 nmol/L). There were no apparent negative clinical or pathologic side effects noted between the groups. This study found that exposing rabbits to UVB radiation long term significantly increased their circulating serum 25-OHD₃ levels, which was sustainable over time.     

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.     

Steroid hormone profile of Markhoz does (Iranian Angora) throughout estrous cycle and gestation period

The present study aims were to determine the profiles of changes in progesterone (P4) and 17-β-estradiol (E2) in the peripheral blood of Markhoz goat (Iranian Angora) during estrous cycle, gestation, and parturition throughout natural breeding season. Gestation length averaged 145.3 ± 0.8 days, and the litter size was 1.1 ± 0.1. Birth weight ranged 2.4–2.8 and 1.5–2.5 kg in male and female kids, respectively. The mean estrous cycle lengths were 20.3 ± 0.4 and 20.9 ± 0.4 days for PGF_2α-induced and natural cycles, respectively. Blood sampling was carried out daily during estrous cycle and weekly during gestation till parturition. E2 attained higher level (24.7 ± 2.15 pg mL⁻¹) at estrus phase and dropped down to the lower level (18.80 ± 1.16 pg mL⁻¹) within 3 to 4 days post-estrus. Concomitantly, P4 started to increase from the mean basal value of 0.5 ± 0.03 ng mL⁻¹ on day 0 to 6.88 ± 0.95 ng mL⁻¹ on day 6 of estrous cycle and reached the peak value of 12.8 ± 0.61 ng mL⁻¹ on day 12. From day 15, a decline was observed in P4 values till the end of the cycle. P4 remained at lower concentrations for 20–50 days of gestation, then increased and reached to its maximum level (13.51 ± 0.279 ng mL⁻¹) in week 15 and returned again to its basal values within 1–2 weeks before parturition. The results will be discussed in terms of the usage of steroid hormone profile in several assisted reproductive technologies.     

Undegraded intake protein supplementation: II. Effects on plasma hormone and metabolite concentrations in periparturient beef cows fed low-quality hay during gestation and lactation

Hereford x Angus cows (n = 36; initial wt 568+/-59 kg) were used to evaluate the effects of undegradable intake protein (UIP) supplementation on plasma hormone and metabolite concentrations. Treatments were control (unsupplemented) or one of three protein supplements. Supplements were fed at 1.3 kg DM/d and included UIP at low, medium, or high levels (53, 223, or 412 g UIP/kg supplement DM, respectively). Supplements were formulated to be isocaloric (1.77 Mcal NEm/kg) and to contain equal amounts of degradable intake protein (DIP; 211 g DIP/kg supplement DM). Prairie hay (5.8% CP) was offered for ad libitum consumption. Jugular blood samples were collected daily from each cow during six 7-d collection periods (corresponding to mo 7, 8, and 9 of gestation and to mo 1, 2, and 3 of lactation). Plasma glucose concentrations were similar between control and supplemented cows during mo 2 and 3 of lactation; however, the low UIP treatment group had consistently higher plasma glucose (P< or =.02) than cows fed medium or high UIP supplements during gestation and the last month of lactation. During gestation, cows fed the high UIP supplement had higher (P< or =.08) plasma glucose than cows fed the medium UIP supplement. During gestation, plasma insulin concentration was increased (P = .01) by supplementation; insulin also increased (P<.01; mo 8 and 9) as supplemental UIP increased. During lactation, plasma insulin was greater (P = .01) in supplemented than in control cows. During mo 2 and 3 of lactation, insulin was lower (P< or =.04) in cows fed low UIP supplement compared with cows fed medium or high UIP supplements. Growth hormone concentration was higher (P< or =.03) in control cows than in supplemented cows in all periods measured except mo 7 of gestation. Plasma nonesterified fatty acid concentrations were higher (P< or =.03) in control cows than in supplemented cows in all periods measured except the 1st mo of lactation. These data are interpreted to suggest that protein supplementation and level of UIP can alter plasma concentrations of hormones and metabolites in gestating and lactating beef cows consuming low-quality hay.     

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.     

Cardiopulmonary effects of combined xylazine-guaiphenesin-ketamine infusion and extradural (inter-coccygeal lidocaine) anaesthesia in calves

Objective To investigate the cardiopulmonary effects of a xylazine–guaiphenesin–ketamine infusion combined with inter‐coccygeal extradural (lidocaine) anaesthesia in calves. Study design Prospective study. Animals Five Holstein Friesian calves (one steer, four heifers) aged 6 weeks weighing 65.2 ± 2.7 kg. Materials and methods Calves were anaesthetized with isoflurane in oxygen for instrumentation. At least 12 hours later, xylazine (0.2 mg kg^?1 IM) was given. After 15 minutes, an infusion of xylazine hydrochloride (0.1 mg mL^?1), guaiphenesin (50 mg mL^?1) and ketamine (1 mg mL^?1) (X–G–K) was infused at a rate of 1.1 mL kg^?1 hour^?1 IV. Oxygen (4 L minute^?1) was delivered by nasotracheal tube 30 minutes later. Inter‐coccygeal (Co₁–Co₂) extradural anaesthesia (lidocaine 2%, 0.18 mL kg^?1) was administered 30 minutes later. Cardiopulmonary variables were obtained in the unsedated standing calves 10 minutes after xylazine, 15 and 30 minutes after X–G–K without O₂, 15 and 30 minutes after X–G–K with O₂ and 5, 15, 30, 45 and 60 minutes after extradural anaesthesia. Data were analysed using a repeated measurement analysis of variance including an autoregressive covariance structure of order 1 (correlations at different time intervals). Results Xylazine caused significant (p < 0.05) decreases in heart rate (HR), cardiac output (Qt) and index (CI), stroke volume and stroke index, mean, systolic and diastolic arterial blood pressure (MAP, SAP, DAP), left (LVWSI) and right ventricular stroke work index (RVWSI), mean, systolic and diastolic pulmonary arterial pressure (MPAP, SPAP, DPAP), arterial pH, arterial oxygen tension (P_aO₂), arterial base excess, arterial HCO₃^? concentration, arterial saturation, packed cell volume, arterial and venous oxygen content (C_aO₂, C_vO₂), O₂ consumption and O₂ delivery (V?O₂, ?O₂). Increases in systemic vascular resistance (SVR) and pulmonary vascular resistance (PVR) were observed. During X–G–K infusion without O₂, HR, Qt and CI increased gradually while SVR, PVR and MAP decreased. Left ventricular stroke work index and P_aO₂ remained constant, while O₂ supplementation improved P_aO₂. Coccygeal extradural anaesthesia had little effect on cardiopulmonary variables. Respiratory rate (f) and P_aCO₂ significantly increased over the experiment. Conclusions and clinical relevance Xylazine caused adverse cardiopulmonary effects in calves. Improvement occurred during xylazine–guiaphenesin–ketamine infusion. Cardiac index and arterial blood pressure remained below baseline values while sustained increases in respiration rate and P_aCO₂ were observed. Inter‐coccygeal extradural anaesthesia had only minor effects. Oxygen supplementation proved advantageous during guiaphenesin, ketamine and xylazine infusion in healthy calves in combination with coccygeal extradural anaesthesia induced persistent cardiopulmonary depression.