Tetracycline Residues in Bovine Muscle and Liver Samples from Sicily (Southern Italy) by LC-MS/MS Method: A Six-Year Study.

Gaetano Cammilleri,Gianluigi Lo Dico,Giuseppe Giangrosso,Antonello Cicero,Vita Giaccone,Vincenzo Giordano,Andrea Pulvirenti,Massimo Vinciguerra,Stefano Vullo,Nicola Cicero,Antonio Vella,Vincenzo Ferrantelli,Andrea Macaluso

doi:10.3390/molecules24040695

Abstract

We examined a total of 369 bovine liver and muscle samples for the detection of oxytetracycline (OTC), tetracycline (TC), chlortetracycline (CTC), and doxycycline (DOX) residues by implementation and validation of a LC-MS/MS method. The method showed good recovery values between 86% and 92% at three levels of concentrations. The linearity tests revealed r2 > 0.996 for all the tetracyclines examined. Furthermore, the Youden test revealed that the method was robust. Only 14.4% of the samples showed OTC and TC residues in a concentration range of 10.4–40.2 µg kg−1. No CTC and DOX residues were found in all the samples analyzed. Liver samples showed the highest average values (31.5 ± 20.6 and 21.8 ± 18.9 for OTC and TC, respectively). The results showed a low incidence of TCs in all the samples examined, in comparison with other studies reported in the literature. A significant decrease in TC residues frequency was found from 2013 (p < 0.05). This work reports for the first time epidemiological data on the presence of TC residues in liver and muscle samples of cattle farmed in Sicily (Southern Italy). The very low incidence of TC residues indicates a continuous improvement in farming techniques in Southern Italy, which is essential to ensure consumers’ protection.

Highlights

Antibiotics are widely used substances in animal farming
Very little is known about the accumulation of these substances in bovine muscle and liver samples farmed in Southern Italy
We examined for the first time in the literature the presence of four tetracyclines residues in muscle and liver samples of cattle raised in Sicily (Southern Italy) by an LC-MS/MS method in order to obtain a six year study on the occurrence of these substances in Southern Italy farms

Summary

Introduction

Antibiotics are widely used substances in animal farming. Among the antibiotics, tetracycline is the most used antimicrobial substances for the prevention of bacterial disease of farmed animals, followed by macrolide, lincosamides, penicillins, and sulphonamides [1,2]. Tetracyclines are one of the cheapest classes of antibiotics available, and their cost in real terms is declining due to improved manufacturing technology [3]. Some tetracyclines such as chlortetracycline, oxytetracycline, Molecules 2019, 24, 695; doi:10.3390/molecules24040695 www.mdpi.com/journal/molecules. The mechanism of action of tetracyclines is bacteriostatic and consists of the inhibition of bacterial protein synthesis. They are able to chelate some divalent cations (Ca2+ ), causing indirectly the inhibition of numerous bacterial enzymatic systems [4]

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Discussion

Conclusion