Pour on application of growth promoters in veal calves: analytical and histological results

Development and Application of a Screening Method of Absolute Quantitative PCR To Detect the Abuse of Sex Steroid Hormone Administration in Male Bovines

A methodology for the absolute quantification of regucalcin gene through quantitative PCR was set up to confirm that the decrease of regucalcin gene expression in the testis is an effective biomarker for tracing sex steroid hormone treatment in bovine husbandry. On the basis of TaqMan technology, an external standard curve was generated. Using in vivo experiments, a ROC curve was developed to calculate the criterion value, specificity, and sensitivity for this potential biomarker. Then, regucalcin gene expression was assessed in veal calves and beef intended for human consumption. In 11 of 54 calves and in 5 of 70 beef cattle the regucalcin gene was expressed under their respective cutoff. Additionally, a mild decrease of regucalcin protein expression was revealed by immunohistochemistry in subjects tested positive via qPCR. These preliminary results suggest that this transcriptomics test may be employed as a novel diagnostic screening tool, improving significantly the overall efficacy of food control.

Multicystic degeneration of the Cowper's gland in a Large White boar

The present report describes a case of multicystic degeneration of the Cowper's gland in a 1.3-year-old purebred Large White intact boar with reduced fertility in Switzerland. Based on the case history, a general physical examination, an andrological investigation and a transrectal ultrasonography combined with a subsequent thorough pathological examination including histology a multicystic degeneration of the Cowper's gland were diagnosed. The case indicates that cystic degeneration of the bulbourethral gland should be contemplated in the differential diagnoses of andrological disorders even though it has not been described in pigs so far. While selecting breeding boars, a morphological check of the bulbourethral gland can be performed, since degeneration of the gland would potentially have an impact on future fertility.

Regucalcin Expression as a Diagnostic Tool for the Illicit Use of Steroids in Veal Calves

It has been previously demonstrated that sex steroid hormone treatment down-regulates regucalcin gene expression in the accessory sex glands and testis of prepubertal and adult male bovines. The aim of this study was to investigate whether low doses of sex steroid hormones combined with other drugs significantly affect regucalcin gene expression in the accessory sex glands and testis of veal calves. The regucalcin expression was down-regulated in the bulbo-urethral glands of estrogen-treated calves, whereas it was up-regulated in the prostate of estrogen-treated calves. Only the testis of androgen-treated calves showed a down-regulation of the regucalcin expression. Thus, the administration of sex steroid hormones, even in low doses and combined with other molecules, could affect regucalcin expression in target organs. Particularly, the specific response in the testis suggests regucalcin expression in this organ as a first molecular biomarker of illicit androgen administration in bovine husbandry.

Set-up of a multivariate approach based on serum biomarkers as an alternative strategy for the screening evaluation of the potential abuse of growth promoters in veal calves

A chemometric class modelling strategy (unequal dispersed classes - UNEQ) was applied for the first time as a possible screening method to monitor the abuse of growth promoters in veal calves. Five serum biomarkers, known to reflect the exposure to classes of compounds illegally used as growth promoters, were determined from 50 untreated animals in order to design a model of controls, representing veal calves reared under good, safe and highly standardised breeding conditions. The class modelling was applied to 421 commercially bred veal calves to separate them into 'compliant' and 'non-compliant' with respect to the modelled controls. Part of the non-compliant animals underwent further histological and chemical examinations to confirm the presence of either alterations in target tissues or traces of illegal substances commonly administered for growth-promoting purposes. Overall, the congruence between the histological or chemical methods and the UNEQ non-compliant outcomes was approximately 58%, likely underestimated due to the blindness nature of this examination. Further research is needed to confirm the validity of the UNEQ model in terms of sensitivity in recognising untreated animals as compliant to the controls, and specificity in revealing deviations from ideal breeding conditions, for example due to the abuse of growth promoters.

Application of absolute qPCR as a screening method to detect illicit 17β-oestradiol administration in male cattle

It has been previously demonstrated that the progesterone receptor gene is up-regulated in the sex accessory glands of pre-pubertal and adult male bovines after 17β-oestradiol treatment. In the present study, a qualitative screening method was optimised to detect 17β-oestradiol treatment using absolute quantification by qPCR of the progesterone receptor gene to determine the amount of gene expression in bulbo-urethral glands. An external standard curve was generated and developed with TaqMan® technology. Based on two in vivo experiments, the decision limit CCα, sensitivity and specificity of this screening method were established. Trial 1 consisted of 32 Friesian veal calves divided into two groups: group A (n = 12), consisting of animals treated with four doses of 17β-oestradiol (5 mg week(-1) per animal); and group B (n = 20), consisting of control animals. Trial 2 was performed on 26 Charolaise beef cattle that either received five doses of 17β-oestradiol (group C; 20 mg week(-1) per animal; n = 6) or remained untreated (group D; n = 20). Further, progesterone receptor gene expression was evaluated in beef and veal calves for human consumption. A specific CCα on 20 Piedmontese control beef cattle was calculated to include these animals in a field investigation. Five out of 190 beef cattle and 26 out of 177 calves tested expressed the progesterone receptor gene above their respective CCα and they were classified as being suspected of 17β-oestradiol treatment. Additionally, 58% of veal calves that tested suspect via qPCR exhibited histological lesions of the bulbo-urethral gland tissue, which are typical of oestrogen administration and are consistent with hyperplasia and metaplasia of the glandular epithelium.

Pathology of the testicle and sex accessory glands following the administration of boldenone and boldione as growth promoters in veal calves

Boldenone and its precursor Boldione are illegally used for anabolic purposes in humans, horses and cattle. To develop more effective policies and programs to maximize food security, Italian Public Health Services investigate all indicators capable of assisting the recognition of treated animals, and prioritize research and the formulation of action strategies for the promotion of healthy eating. Thus, an experimental administration of boldenone and boldione at anabolic dosages in veal calves was carried out to evaluate the changes in target organs by qualitative and semi-quantitative morphological analysis. The lesions resembled the effects already observed after the administration of androgen hormones to cattle. Main findings were represented by prostate hypersecretion, increased rate of apoptotic cells and decreased rate of Ki67 positive cells in the germ cell line of treated animals, particularly in boldione group and finally some new features like hypertrophy of the prostate urothelial cells.

Influence of 17beta-oestradiol, nortestosterone and dexamethasone on the adaptive immune response in veal calves

In veal calf production androgens, estrogens and glucocorticoids are used to stimulate growth. However, sexhormones and glucocorticoids also influence the function of the immune system. From studies in humans and mice, androgens are known as immunosuppressive, while estrogens stimulate the production of antibodies and glucocorticoids also enhance the T-helper 2 response. To investigate whether the adaptive immune system is influenced by hormone administration, calves were treated with a hormone cocktail containing androgens, estrogens and glucocorticoids and vaccinated against Mycobacterium avium spp. paratuberculosis. The activity of the adaptive immune system was measured by using an antigen specific elispot assay (ES), lymphocyte stimulation test (LST) and an enzyme-linked immuno sorbent assay (ELISA). The results showed that the hormone treatment did not lead to significant differences in the function of the adaptive immune system between the hormone treated and the not hormone treated group while growth was stimulated in the hormone treated group.

Reference Histology of Veal Calf Genital and Endocrine Tissues ? An Update for Screening on Hormonal Growth Promoters

An animal experiment has been performed with 42 veal calves, 21 males and 21 females, which were fed and housed according to European regulations for veal calves. The animals were kept in six groups of seven animals and fed milk replacer supplemented with three different levels of lactulose (0%, 1% and 3%) and some roughage. At the start of the experiment the animals were 1-3 weeks of age and they were slaughtered at 26 weeks. From male animals prostate, bulbo-urethal gland and testes were sampled, from female animals Bartholin's gland, uterus, cervix and ovaries were sampled. From all animals thyroid, thymus, adrenals, liver and kidneys were sampled. Histological investigation of the prostates and bulbo-urethral glands showed normal histology. This means that dilated tubules, strong secretion, increased mucinous glandular tissue and severe hyperplasia and squamous metaplasia, as is regularly observed in practice in the Netherlands, were not present in these animals. None of these prostates would be judged as positive in the screening for hormones as is performed by the Dutch Food and Consumer Product Safety Authority (VWA). The female calves also showed normal histology of Bartholin's gland except for three animals that appeared to be in oestrus and showed some metaplasie of the ducts but with a normal gland to duct ratio. These animals would be judged as suspect. The liver and kidney showed minor alterations due to slight infections during the experimental period. This experiment showed that it is possible to raise veal calves according to the practice without getting positive histology in the prostate or Bartholin's gland.

Effects of phyto-oestrogens on veal calf prostate histology

In veal calf production plant-based proteins are frequently included in milk replacer fed to the animals. Since soy products, which are mostly used, are known for their high levels of phyto-oestrogens, the effects of these feeds on the veal calf prostate were examined. Goal was to determine whether these compounds could interfere with histological screening for oestrogenic growth promoters. In a feeding experiment, four groups of veal calves fed plant-based protein-supplemented milk replacer (PBM), containing 5% soy concentrate, 5% soy isolate, 5% wheat gluten and 2% potato protein, for 4 weeks were compared to animals fed dairy-based control feed (DBM); animals treated with estradiol benzoate, diethylstilbestrol and ethinylestradiol served as positive controls. Daidzein and genistein levels measured in feed and urine showed high levels of genistein and daidzein in the soy isolate and soy concentrate supplemented feeds. Genistein and daidzein were also found in the urine of the animals that were fed these feeds. Haematoxylin-eosin-stained prostate sections of PBM-fed animals showed slight hyperplasia and some dilated tubules as compared to the DBM-fed group, but no metaplasia, which is used for screening for oestrogenic hormones. The positive controls showed extensive squamous metaplasia. Immunohistochemical staining for cytokeratin 5 (using RCK 103 monoclonal antibody) in basal cells showed a normal staining pattern of basal cells in the DBM-fed calves and extensive basal cell proliferation and squamous metaplasia in the oestrogen-treated positive control animals. PBM-fed calves showed no increase of basal cell staining but showed elongations of the basal cells in most animals, sometimes resulting in circular figures. It is concluded that the feeds examined in this study did not interfere with histological screening for oestrogens in male veal calves.

Expression analysis of androgen-responsive genes in the prostate of veal calves treated with anabolic hormones

In order to identify indirect molecular biomarkers of anabolic treatments in veal calves, an animal experiment was performed using two combinations of growth promoters (consisting of boldenone undecylenate and estradiol benzoate, and of testosterone enantate and estradiol benzoate). We selected a set of 12 genes that are known to be androgen responsive in other mammalian species. The expression profile of this set of genes was analysed on prostate samples of veal calves using a real-time RT-PCR approach. For each selected gene the corresponding bovine sequence was obtained and a gene specific real-time assay was optimised and validated. The amplification was shown to be highly specific, linear and efficient. High reproducibility (<1%) and low-test variability (<2.5%) were also been achieved. Messenger RNA levels were quantified in prostate samples, non-parametric analysis of variance showed significant up-regulation of three genes (MAF, ESR1 and AR) and significant down-regulation of four genes (HMGCS1, HPGD, DBI, and LIM) in treated samples when compared with untreated controls. To assess the possibility of identifying hormone-treated animals by molecular means we performed a discriminant analysis that was effective in classifying treated and non-treated samples with an accuracy of 93%. Our results indicate that identification of treatment with steroid hormones in veal calves by means of gene expression analysis is a feasible approach and could be improved increasing both the number of genes and the number of controls analysed.

Effects of Low-dose Dexamethasone on Thymus Morphology and Immunological Parameters in Veal Calves

Glucocorticoids are often illegally used in association with anabolic steroids as growth promoters in veal calves and beef production. An experimental administration of dexamethasone was carried out in veal calves in order to assess the role of low doses of exogenous glucocorticoids on induction of thymus atrophy and on the immune response. Three groups of five veal calves each were included in this study: group D was administered 0.4 mg/day of dexamethasone-21-phosphate per os for 25 days; group V was administered 2 mg of dexamethasone-21-isonicotinate i.m. at days 14 and 21, and group K served as control. At slaughter, the weight of the thymus was severely reduced in group D and in group V, compared with control animals. Lesions included severe lymphoid depletion and hyperplasia of adipose tissue. In situ evaluation of apoptosis in thymus, showed a reduction of the percentage of positive nuclear areas of animals belonging to group V in comparison with control animals. An overall decrease of lymphocyte proliferative response was detected after treatment with short acting dexamethasone, while antibody response was not affected by treatments.