Type 2 diabetes mellitus with pancreatic β cell dysfunction in 3 horses confirmed with minimal model analysis

Reasons for performing study: Type 2 diabetes mellitus (T2DM) is diagnosed rarely in equine practice although it may be under‐recognised. A greater awareness of the condition and therapeutic considerations would be to the benefit of such cases presenting in practice. More investigation into the pharmacological management of these cases is needed. Objectives: Three cases of diabetes mellitus were investigated using a specific test for insulin sensitivity and pancreatic β cell function in order to define accurately and characterise the existence of T2DM in all 3 subjects. Methods: The insulin‐modified frequently sampled i.v. glucose tolerance test was performed in each case and the data so obtained were subject to minimal model analysis of insulin‐glucose dynamics. Cases were then monitored following treatment using a combination of dietary modification, metformin, glibenclamide and pergolide. Results: Marked insulin resistance was identified in each case and, furthermore, severe pancreatic β cell dysfunction was present therefore classifying each case as end stage T2DM. Treatment was nevertheless associated with restoration of normoglycaemia in all cases. Conclusions: T2DM in horses may be more common than generally considered. In some cases individuals may respond to therapy aimed at restoring insulin sensitivity and pancreatic function. Drugs used in other species for the treatment of T2DM have not yet been adequately tested in horses. Potential relevance: T2DM should be considered as an important differential diagnosis in mature to elderly horses and ponies suffering from weight loss, polydipsia and polyuria. Clinicians should be encouraged to offer treatment and management advice when such cases are encountered.     

α- and β-adrenoceptors in the sheep urinary bladder

A study was undertaken to determine the presence and distribution of alpha- and beta-adrenoceptors in the sheep bladder body and base. In the bladder body, noradrenaline and isoproterenol induced relaxation which was significantly inhibited by propranolol, pafenolol and butoxamine. In the presence of propranolol (10(-5) M), noradrenaline induced a small contraction, as well as phenylephrine, but B-HT 920 failed to cause any effect on the bladder body. In the bladder base, noradrenaline caused a contraction that was significantly inhibited by prazosin but not by yohimbine. Phenylephrine also induced a contractile response in this structure which was inhibited by prazosin. Isoproterenol caused a relaxation that was significantly inhibited by propranolol and pafenolol but not by butoxamine. Relaxation was mediated by both beta 1 and beta 2-adrenoceptors in the detrusor muscle and by beta 1-adrenoceptors in the bladder base. Alpha 1-adrenoceptors contributed to maintain the detrusor tone and contract the bladder base.     

Effects of β‐carotene‐enriched dry carrots on β‐carotene status and colostral immunoglobulin in β‐carotene‐deficient Japanese Black cows

Data from 18 β‐carotene‐deficient Japanese Black cows were collected to clarify the effects of feeding β‐carotene‐enriched dry carrots on β‐carotene status and colostral immunoglobulin (Ig) in cows. Cows were assigned to control or carrot groups from 3 weeks before the expected calving date to parturition, and supplemental β‐carotene from dry carrots was 138 mg/day in the carrot group. Plasma β‐carotene concentrations in the control and carrot groups at parturition were 95 and 120 μg/dL, and feeding dry carrots slightly improved plasma β‐carotene at parturition. Feeding dry carrots increased colostral IgA concentrations in cows and tended to increase colostral IgG₁, but colostral IgM, IgG₂, β‐carotene and vitamin A were not affected by the treatment. Feeding dry carrots had no effects on plasma IgG₁, IgA and IgM concentrations in cows, but plasma IgG₁ concentrations decreased rapidly from 3 weeks before the expected calving date to parturition. These results indicate that feeding β‐carotene‐enriched dry carrots is effective to enhance colostral IgA and IgG₁ concentrations in β‐carotene‐deficient cows.     

Dietary supplementation of β‐hydroxy‐β‐methylbutyrate in animals – a review

The leucine metabolite β‐hydroxy‐β‐methylbutyrate (HMB) has been studied by many researchers over the last two decades. In particular, the utility of HMB supplementation in animals has been shown in numerous studies, which have demonstrated enhanced body weight gain and carcass yield in slaughter animals; positive immunostimulatory effect; decreased mortality; attenuation of sarcopenia in elderly animals; and potential use in pathological conditions such as glucocorticoid‐induced muscle loss. The aim of this study was to summarize the body of research on HMB supplementation in animals and to examine possible mechanisms of HMB action. Furthermore, while the safety of HMB supplementation in animals is well documented, studies demonstrating efficacy are less clear. The possible reasons for differences in these findings will also be examined.     

The Relationship Among Vitamin C, β‐carotene,Vitamin A,Progesterone and Oestradiol 17‐β Concentrations in Plasma and Cyst Fluid of Holstein Cows with Ovarian Cyst

The aims of this study were to determine the concentrations of the progesterone, oestradiol‐17‐β, vitamin A, C and β‐carotene in plasma and cyst fluid and to relate these values with cystic diameter and membrane thickness of Holstein cattle with ovarian luteal cyst. 1650 Holstein cows were examined for the presence of the ovarian cyst and luteal and follicular cystic ovaries were obtained following slaughtering in personal slaughterhouse in Konya‐Turkey. 15 Luteal and 15 follicular cystic ovaries were distinguished by rectal palpation and by post mortem ultrasonographic examination. Plasma and cyst fluid, hormone and vitamin analyses were carried out by EIA method and spectrophotometric measurement respectively. Although there was no relationship between β‐carotene and vitamin A in plasma and cyst fluid of both cyst type and hormone concentrations, the vitamin C concentration of cyst fluid was found significantly higher in luteal cyst than in follicular cyst. Moreover, there is a positive correlation among values of the vitamin C concentrations of cyst fluid and cystic membrane thickness, plasma and the cyst fluid progesterone concentrations, but there is a negative correlation among the vitamin C concentrations of cystic fluid and oestradiol 17β levels of plasma and cyst fluid. In conclusion, vitamin C concentration of cyst fluid supported ultrasonographic and endocrinologic findings. Also, it can be postulated that vitamin C is probably effective on progesterone synthesis in the luteal tissue of cyst.     

Effect of β‐carotene on health status and performance of sows and their litters

A total of 48 sows were allocated to four groups (12 sows per group) at the 99th day of pregnancy and were treated throughout two consecutive breeding cycles, as follows: (a) control group: no treatment; (b) group BC1: 400 mg β‐carotene/sow/day via feed from 7 days prior to the expected farrowing, until the 30th day postservice; (c) group BC2: 400 mg β‐carotene/sow/day via feed from 7 days before weaning up to service, followed by 200 mg β‐carotene until the 30th day postservice; and (d) group BC inj: four intramuscular (i.m.) injections of 200 mg β‐carotene/sow (on the 100th day of pregnancy, on the day of farrowing, on the day of weaning and on the first day of oestrus). Serum β‐carotene equivalents, vitamin A and IgG concentrations were determined in sows at several times of the breeding cycle. Moreover, serum IgG concentrations were determined in piglets on the second day of lactation and at weaning. Data relating to sow reproductive parameters and litter parameters were also recorded. It was shown that concentrations of serum β‐carotene equivalents were elevated only in the BC inj group during lactation and at service, while serum vitamin A concentrations were also elevated in the BC inj group only at oestrus. There was no effect of β‐carotene on the oestrus intensity score, the weaning‐to‐oestrus interval, the number of returns to oestrus per sow and the farrowing‐to‐farrowing interval. The number of piglets born alive was greater in the BC inj group compared with the controls, while the litter size at weaning was greater in the groups BC1, BC2 and BC inj compared with the control group (p < 0.05). Supplementation of β‐carotene did not appear to influence the serum IgG concentration in sows and piglets.     

Effects of supplemental β‐carotene on colostral immunoglobulin and plasma β‐carotene and immunoglobulin in Japanese Black cows

Data from 26 Japanese Black cows were collected to clarify the effects of supplemental β‐carotene on colostral immunoglobulin (Ig) and plasma β‐carotene and Ig in the cows. Cows were assigned to control or β‐carotene groups from 21 days before the expected calving date to 60 days after parturition. Supplemental β‐carotene was provided at 500 mg/day in the β‐carotene group. Supplemental β‐carotene drastically increased plasma β‐carotene concentrations in the cows from parturition to 60 days after parturition, and plasma β‐carotene concentrations in the control and β‐carotene groups at parturition were 202 and 452 μg/dl, respectively. Supplemental β‐carotene had no effects on plasma IgG₁, IgA or IgM concentrations at parturition. Supplemental β‐carotene increased colostral IgG₁ concentrations in the cows, but colostral β‐carotene, IgA and IgM concentrations were not affected by supplemental β‐carotene. These results indicate that supplemental β‐carotene is effective to enhance colostral IgG₁ concentrations and plasma β‐carotene concentrations in Japanese Black cows.     

Retinol, β-carotene and β-tocopherol concentrations in mare and foal plasma and in colostrum

Fat-soluble vitamins transfer poorly across the diffuse epitheliochorial placenta of the mare, so the neonatal foal is dependent on its supply via colostrum. Concentrations of retinol (RT), β-carotene (BC), and β-tocopherol (AT) were assayed in samples of plasma, colostrum and milk from nine mares of mixed light breeding and their foals at parturition and days 1, 2, and 4 postpartum. Samples were analyzed simultaneously for RT, BC, and AT using a new, less time-consuming reverse phase high-pressure liquid chromatography (HPLC) method. Feeds were analyzed, and mean daily intakes calculated. Mare plasma RT increased from day 1 to day 4 (P = .033), and plasma AT declined linearly from day 0 to day 4 (P = .006). Colostrum concentrations of all vitamins increased from parturition to day 1, and then declined rapidly over the 4 days. Foal plasma BC increased from parturition to day 4 (P = .080), and plasma AT increased from parturition to day 2 (P < .001), and 4 (P = .060). These observations suggest that three times the current recommendation of vitamin A is sufficient for pregnant mares, in keeping with previous studies of growth, pregnancy, and lactation. In contrast, the linear decrease in mare plasma AT suggests that 1.2 times the current recommendation of vitamin E may be less than optimal for pregnant mares.

Introduction

The diffuse epitheliochorial placenta of the mare does not allow fat-soluble vitamins to cross with ease to the fetus,[1] so their status in the neonatal foal is dependent on colostrum. This first milk contains these vitamins, which are necessary for many functions.Vitamin A is required for vision, reproduction, growth, development, and maintenance of epithelial cells, and osteoclast activity in bone formation. In addition, vitamin A deficiencies reduce resistance to disease, can cause neurological degeneration, and congenital defects.[2] Vitamin E, an antioxidant, prevents lipid peroxidation and cell membrane damage. Its deficiency in horses has been associated with a form of muscular dystrophy and impaired immune function. [3]Studies on the mare and foal have described blood concentrations of one or two of these vitamins,[4, 5 and 6] but only one involved all three. [7] In that study, vitamin concentrations were assayed in mare blood and milk, but only once in foal blood at parturition, so data during the periparturant period is incomplete.The objectives of this enumerative study were to determine concentrations of RT, BC, AT in plasma and colostrum, to evaluate colostral transfer of these vitamins, to assess the adequacy of vitamin intakes of mares, and to develop a time-saving single-run HPLC method.

Materials and methods

Animals

Nine healthy aged multiparous mares of mixed light breeding (13.6 ± 1.5 years, 592 ± 20 kg body mass) and their foals were sampled. The institutional animal care and use committee approved the protocol. Mares were kept on meager late-winter mixed grass pasture, with free access to round bale orchard and fescue grass hay, water, and trace mineral/vitamin salt. They were fed 2 kg of concentrate twice daily at 7:00 and 3:00 . The diet met or exceeded current recommendations for pregnant mares at 11 months gestation for energy.[8] Samples of hay and concentrate were submitted for partial proximate analysis to the Virginia Tech Forage Testing Laboratory where standard AOAC [9] methods are used ( Table 1). Samples of feeds were also taken for analysis of RT, BC, and AT ( Table 2).     

Expression of VEGFR and PDGFR‐α/‐β in 187 canine nasal carcinomas

Radiotherapy represents the standard of care for intranasal carcinomas. Responses to tyrosine kinase inhibitors (TKIs) have been reported but data on expression of target receptor tyrosine kinases (rTKs) is limited. This study characterizes the expression of vascular endothelial growth factor receptor (VEGFR), platelet‐derived growth factor receptor (PDGFR)‐α and PDGFR‐β in canine intranasal carcinomas. Histological samples from 187 dogs were retrieved. Immunohistochemistry was performed using commercially available antibodies. Expression of rTKs was classified into weak, moderate or intense and additionally recorded as cytoplasmic, membranous, cytoplasmic‐membranous, nuclear or stromal. VEGFR was expressed in 158 dogs with predominantly moderate expression (36.9%) and a cytoplasmic‐membranous expression pattern (70.9%). PDGFR‐α was detected in 133 with predominantly weak expression (57.9%) and cytoplasmic pattern (87.9%). PDGFR‐β was identified in 74 patients with a predominantly moderate expression (17.6%) and cytoplasmic expression pattern (63.5%). Co‐expression of rTKs was common. These results confirm expression of VEGFR, PDGFR‐α and PDGFR‐β in canine intranasal carcinomas and support the utility of TKIs.     

β‐hydroxy‐β‐methyl butyrate promotes leucine metabolism and improves muscle fibre composition in growing pigs

The aim of this study was to investigate the effects of excess leucine (Leu) vs. its metabolites α‐ketoisocaproate (KIC) and β‐hydroxy‐β‐methyl butyrate (HMB) on Leu metabolism, muscle fibre composition and muscle growth in growing pigs. Thirty‐two pigs with a similar initial weight (9.55 ± 0.19 kg) were fed 1 of 4 diets for 45 days: basal diet, basal diet + 1.25% L‐Leu, basal diet + 1.25% KIC‐Ca, basal diet + 0.62% HMB‐Ca. Results indicated that relative to the basal diet and HMB groups, Leu and KIC groups exhibited increased Leu concentrations and decreased concentrations of isoleucine, valine and EAAs in selected muscle (p < 0.05) and had lower mRNA levels of MyHC I and higher expression of MyHC IIx/IIb (p < 0.05), and there was no significant difference between the basal and HMB‐supplemented groups. Moreover, the mRNA expression levels of AMPKα and UCP3 were higher but the myostatin mRNA levels were lower in the soleus muscle of the HMB group than those from other groups (p < 0.05). These findings demonstrated that doubling dietary Leu content exerted growth‐depressing effects in growing pigs; dietary KIC supplementation induced muscular branched‐chain amino acid imbalance and promoted muscle toward a more glycolytic phenotype; while dietary HMB supplementation promoted the generation of more oxidative muscle types and increased muscle growth specially in oxidative skeletal muscle, and these effects of HMB might be associated with the AMPKα‐Sirt1‐PGC‐1α axis and mitochondrial biogenesis.     

Genetic Characterization of Antibiotic Resistance in Enteropathogenic Escherichia coli Carrying Extended‐Spectrum β‐Lactamases Recovered from Diarrhoeic Rabbits

A total of 52 Escherichia coli strains isolated from diarrhoeic rabbits were investigated for their enteropathogenic E. coli (EPEC) pathotype by PCR amplification of eae and bfp virulence genes. A total of 22 EPEC isolates were identified, serotyped and studied for antibiotic resistance and screened for the detection of extended‐spectrum β‐lactamases (ESBLs). The EPEC isolates belonged to three serogroups (O26, O92 and O103). The most common serogroup (O103:K‐:H2) was observed among 17 EPEC strains, the O92:K‐serogroup in three isolates (the antibiotic sensitive ones) and the remaining O26:K‐serogroup in two isolates (the ESBLs isolates). Resistances to ampicillin and tetracycline were the most frequent and detected followed by resistance to nalidixic acid, streptomycin, trimethoprim–sulphamethoxazole, cefoxitin, gentamicin and ciprofloxacin. All the isolates were sensitive for amikacin, ceftazidime, aztreonam, imipenem, chloramphenicol, tobramycin and amoxicillin + clavulanic acid. Two isolates recovered from two adult animals showed an intermediate susceptibility to cefotaxime, and a positive screening test for ESBL was demonstrated in both. The bla_TEM gene was demonstrated in the majority of ampicillin‐resistant isolates. The aac(3)‐II or aac(3)‐IV genes were detected in the four gentamicin‐resistant isolates. In addition, the aadA gene was detected in 60% of streptomycin‐resistant isolates. The tet(A) or tet(B) genes were identified in all tetracycline‐resistant isolates. A total of nine EPEC isolates showed the phenotype SXT‐resistant, and the sul1 and/or sul2 and/or sul3 genes were detected in all of them. Our findings showed that the molecular detection by the eae and bfp genes by PCR followed by serotyping is useful for monitoring trends in EPEC infections of rabbits allowing the identification of their possible reservoirs. The detection of genes involved in the resistance to antibiotics of different families in a relatively high proportion of faecal E. coli isolates of rabbits is of great interest and could be considered a serious public health problem.     

Effects of maternal treatment with β‐hydroxy‐β‐metylbutyrate and 2‐oxoglutaric acid on femur development in offspring of minks of the standard dark brown type

The aim of the study was to evaluate the effect of the diet, mother type and sex of the offspring on the mechanical and geometric parameters of long bones as well as bone tissue density in minks. Primiparous and multiparous dams were supplemented with β‐hydroxy β‐methylbutyrate (a metabolite of leucine, at the daily dosage of 0.02 g/kg of body weight) and/or 2‐oxoglutaric acid (a precursor of glutamine, at the daily dosage of 0.4 g/kg of body weight) during gestation. The diet did not influence bone tissue density and the length of the humerus. An increase in the length of the femur was noted in male offspring delivered by multiparous dams. The diet resulted in an increase in the weight of the humerus in males from multiparous dams and a decrease in offspring from primiparous dams. Heavier femora were noted in male offspring delivered by both types of dams. The maximum elastic strength of the humerus was higher in the offspring delivered by multiparous than primiparous dams, irrespective of the offspring sex. The diet resulted in reduction in the ultimate strength of the femur in the male offspring delivered by primiparous dams. Only females born by multiparous dams, irrespective of the diet, showed a significant increase in the cross‐sectional area of the humerus, while a significant decline was noted in males delivered by multiparous dams and in all the offspring delivered by primiparous dams. An increase in the cross‐sectional area of the femur was noted in the offspring delivered by multiparous dams, while reduction was observed in the offspring delivered by primiparous dams. These results have shown for the first time that the presence of β‐hydroxy‐β‐methylbutyrate or 2‐oxoglutaric acid in the diet of pregnant primiparous or multiparous dams unambiguously affects the geometry and mechanical properties of offspring's long bones.     

Epidemiological features and association with crib‐biting in horses with neurological disease associated with temporohyoid osteoarthropathy (1991–2008)

A retrospective study of 43 cases of temporohyoid osteoarthropathy was performed to evaluate the epidemiological features and a possible association with crib‐biting. Data collected from records included case details, what diagnostics were utilised, whether medical or surgical treatment was administered, and outcome. Owners were contacted via telephone and asked whether the horse had displayed crib‐biting behaviour. Forty‐three horses were diagnosed with neurological disease associated with temporohyoid osteoarthropathy, 62.8% of which were Quarter Horse‐types. Median age at presentation was 10 years and median duration of neurological signs prior to presentation was 3 days. Skull radiographs and guttural pouch endoscopy were used to definitively diagnose temporohyoid osteoarthropathy in 72% of the cases. Of 43 horses, 21 received medical treatment and 15 surgical treatment, with an overall survival rate of 55.8%. Crib‐biting was observed in 31.3% of cases and there was a significant association between being afflicted with THO and likelihood of possessing the behaviour. Horses with neurological disease associated with THO were 8 times more likely to be crib‐biters compared to the general population.     

Effects of selective α2‐adrenergic receptor agonists on electrical field‐stimulated contractions of isolated bronchi in horses

We investigated the effects of different selective α₂‐adrenergic receptor (AR ) agonists (detomidine, medetomidine, xylazine, and brimonidine) on the contractions of horse‐isolated bronchi induced by electrical field stimulation (EFS ) and by carbachol. No effects were observed on the contraction induced by carbachol, while α₂‐AR agonists reduced EFS ‐evoked contractions in a concentration‐related fashion. The rank order of potency (pD ₂) was brimonidine (7.40 ± 0.20) >medetomidine (7.09 ± 0.24) >detomidine (6.13 ± 0.55) >xylazine (4.59 ± 0.16). The maximal effects (E_max) were ?56.3% ± 6.3%, ?40.4% ± 6.9%, ?48.6% ± 9.9%, and ?72.7% ± 12.7% for brimonidine, medetomidine, detomidine, and xylazine, respectively. Adrenergic block by guanethidine enhanced the potency (8.10 ± 0.05, 7.30 ± 0.15, 6.83 ± 0.41, and 5.40 ± 0.22) and the efficacy (?95.2% ± 0.7%, ?45.2% ± 11.7%, ?58.5% ± 9.8%, and ?97.9% ± 0.6%) of brimonidine, medetomidine, detomidine, and xylazine, respectively. Selective α₂‐AR antagonist, atipamezole, competitively antagonized the inhibition of EFS ‐evoked contractions induced by all agonists except xylazine. These results suggest the existence of presynaptic α₂‐AR s on cholinergic neurons, negatively regulating the release of acetylcholine in horse bronchial muscle, and that α₂‐AR agonists may be beneficial against vagally mediated bronchoconstriction.