Effects and detection of Nandrosol and ractopamine administration in veal calves

The present study describes different effects of the selective androgen receptor modulator (SARM) nandrolone phenylpropionate (Nandrosol) and the β-agonist ractopamine administration in veal calves, and it investigates different strategies applied to trace these molecules. Morphological changes of gonads and accessory glands attributed to androgen effects, such as testicular atrophy, seminiferous tubule diameter reduction and hyperplasia of prostate epithelium, were detected, although SARMs are not described to cause these lesions. The gene expression analysis showed an anabolic activity of Nandrosol in Longissimus dorsi muscle, where myosin heavy chain (MYH) was significantly up-regulated. An IGF1 increase was weakly significant only in Vastus lateralis muscle. In conclusion, the anatomo-histopathological observations and the MYH mRNA up-regulation in Longissimus dorsi muscle confirm the androgenic treatment in experimental animals. The biosensor assay was not enough sensitive to detect residues in urines and only the direct chemical analysis of urine samples confirmed both β-agonist and SARM treatment.

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.