Histopathology as a simple and reliable method to detect 17β-oestradiol illegal treatment in male calves

Thymus and meat physicochemical measurements to discriminate calves treated with anabolic and therapeutic doses of dexamethasone

To preserve the Europe consumers' health, the use of glucocorticoids as growth promoters is prohibited in cattle fattening. In 2008, the Italian Ministry of Health associated to the official control a national monitoring plan based on the histological thymus analysis to identify animals illegally treated with corticosteroids. However, since corticosteroids are authorized and widely used for therapeutic purposes, it is necessary to verify whether the thymus histological test and some physicochemical traits in meat are able to discriminate doped calves from dexamethasone therapeutic treated ones. The aims of this study were (i) to establish whether the therapeutic and illicit corticosteroid treatments of calves could be differentiated through histological evaluation of thymus and by physicochemical meat traits; (ii) to identify a restricted number of physicochemical traits that could differentiate dexamethasone treated from untreated calves. Three groups of 15 calves each were included in this study: group dexamethasone therapeutic treatment treated with dexamethasone 21-phosphate disodium salt at a therapeutic dose (2 mg/kg of live weight for three consecutive days); group dexamethasone anabolic treatment orally treated with dexamethasone 21-phosphate disodium salt according to a presumed anabolic protocol (0.4 mg/day per animal for 20 days); group placebo control treated with a placebo served as control. Results demonstrated that groups could be easily discriminated by thymus microscopy as well as by two meat markers, namely, cooking loss and shear firmness or Warner-Bratzler shear force. The combination of thymus microscopic features and meat physicochemical traits could be used as a practical, economic and accurate screening strategy to discriminate between meat from illegally and therapeutically treated calves. This new reliable and simple tool could contribute to identify animals treated with dexamethasone in those countries where glucocorticoids are illegally used as growth promoters. More in general, this system could be included in the framework of official controls, and applied to verify suppliers' reliability by the meat industry.

Semiquantitative immunohistochemical detection of progesterone receptors in male accessory sex glands as a screening assay for anabolic steroid use in bulls

We investigated the immunohistochemical expression of progesterone receptors (PRs) in the prostate and bulbourethral glands of thirty-two 10–14-mo-old Charolais bulls following treatment with a low dosage of estrogens. Animals were divided into 2 groups: 16 animals (group T) were treated for 71 d with a therapeutic dose of trenbolone acetate and estradiol by subcutaneous implant, 16 animals (group C) received no treatment. Urine samples were collected both at the beginning of the trial and 9 times during the study. A semiquantitative analysis of immunohistochemistry (IHC) was performed by counting the number of positive cells in 10 randomly selected high-power fields (hpf). Both groups showed no significant histologic lesions. IHC examination showed positive cells in the epithelium of both glands, with different patterns of distribution between groups. In group C, IHC-positive cells per hpf varied from 0 to 40 in the prostate and from 0 to 32 in the bulbourethral gland. In group T, positive cells varied from 0 to 85 per hpf in the prostate and from 0 to 75 in the bulbourethral gland. The treated group showed significantly higher median numbers of positively stained cells in both organs than the controls (  p < 0.001). Chemical analysis of the urine samples confirmed that the experimental treatment mimics continuous, low-dose administration of anabolic steroids. IHC quantification showed good sensitivity with a high predictive power to correctly classify treated animals and could be used as a preliminary screening test in bulls.

Confirmation of the progesterone receptor as an efficient marker of treatment with 17β-estradiol in veal calves

Under current European Union legislation the use of anabolic steroids in food-producing livestock is banned because of their long-term adverse effects on human health. We examined the expression profile of the immunohistochemical marker progesterone receptor in veal calves' sex accessory glands following experimental administration of anabolic compounds. The aim was to confirm the accuracy of the immunohistochemical approach in the detection of the over-expression of the progesterone receptor induced by the administration of sexual steroids at low levels (17β-estradiol and nandrolone alone or in combination). A total of 217 male veal calves were randomly divided into four groups: group A (104 calves) treated with 17β-estradiol (5 mg/head; 4 weekly injections); group B (20 calves) treated with nandrolone (50 mg/head; 4 weekly injections); group C (20 calves) treated with the association of the two steroids (5 mg estradiol + 50 mg nandrolone; 4 weekly injections); and group K (73 calves) kept as a control. All the sexual accessory glands were collected at the slaughterhouse (15 days after the last administration) and subjected to immunohistochemical staining with anti-progesterone receptor antibody. All the calves treated with 17β-estradiol alone or in association with nandrolone (groups A and C) showed strong positivity, while nandrolone-treated calves and controls (groups B and K) gave negative results to the immunohistochemical investigation. The statistical analysis showed that the progesterone receptor is a significant predictor of 17β-estradiol treatment alone or in association with nandrolone (p < 0.001): the immunohistochemical study resulted in 100% sensitivity (CI = 95%: 97.1-100%) and specificity (CI = 95%: 95.1-100%) for prostate and 99% sensitivity (CI = 95%: 95.6-100%) and 100% specificity (CI = 95%: 95.1-100%) for bulbo-urethral glands. The data confirm that this innovative biological approach offers a reliable tool to enhance the efficacy of the histological test to detect illegal treatments with estrogens alone or in association with androgens.

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.