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New Concord, OH, United States

Gaikowski M.P.,U.S. Geological Survey | Mushtaq M.,Schering | Cassidy P.,Ricerca Biosciences | Meinertz J.R.,U.S. Geological Survey | And 3 more authors.

Aquaflor®, a 50% feed premix containing the broad spectrum antibacterial agent florfenicol is available globally to control mortality associated with economically significant systemic bacterial diseases of fish. Florfenicol (FFC) is effective in controlling mortality associated with Streptococcus iniae in tilapia Oreochromis sp. when administered in medicated feed at a dose of 15 mg/kg bodyweight (BW)/d for 10 consecutive days. Our objective was to characterize the depletion of the FFC marker residue, florfenicol amine (FFA), from the edible tissue of market-weight Nile tilapia O. niloticus x O. niloticus and hybrid tilapia O. niloticus x O. aureus offered feed medicated with FFC at a nominal dose rate of 15 mg/kg BW/d for 12 days. Near market-weight tilapia were obtained from a commercial tilapia farm, distributed to 2 single pass (one for Nile tilapia and one for hybrid tilapia), flow-through systems and maintained at 27 °C under a 15 h light:9 h dark photoperiod over a 41-d pre-dosing period. During the dosing period, tilapia were offered feed medicated with FFC at a concentration of 1.479 g/kg at 1% BW daily divided in three equal offerings. The initial 10-d dosing period was extended to 12 d because one tank did not consume > 75% of the feed offered during the first two dosing days. The total dose consumed by fish in each of the 2 tanks ranged from 147 to 167 mg/kg. Once during the pre-dose period and on days 1, 2, 4, 7, 14, 21, and 28 of the post-dose period, groups of fish were indiscriminately removed from each tank, measured for weight and length, scaled, filleted, and the skin-on fillets stored at <-70 °C. Frozen fillets were individually homogenized, extracted, and FFA concentration was determined by high-performance liquid chromatography with UV detection. Florfenicol amine is rapidly eliminated from tilapia fillet after withdrawal from medication and depletion followed first-order kinetics with an estimated half-life of 2.32 d. The FFA tolerance limit, calculated as the 99th percentile of the potential residue level at 95% confidence, had depleted to less than the 1 μg/g maximum residue level by 6.14 d after the dosing period. Source

Barrow P.C.,Ricerca Biosciences
Methods in molecular biology (Clifton, N.J.)

A pediatric assessment is now a required component of every New Drug Application in North America or Marketing Authorization Application in Europe, unless a waiver has been granted previously. Nonclinical juvenile toxicity studies are usually required as part of this assessment. The protocols for juvenile toxicity studies are devised in consultation with the FDA or EMEA. It is important to approach the regulatory authority well in advance in order not to delay the marketing authorization of the drug and to confirm the need or not to perform a preclinical evaluation in juvenile animals. The choice of species and the design of juvenile studies are based on a series of complex considerations, including: the therapeutic use of the drug, the age at which children will be treated, the duration of treatment, and potential age- or species-specific differences in pharmacokinetics or toxicity. Source

Reynaud L.,Ricerca Biosciences | Jocteur-Monrozier A.,Ricerca Biosciences
Methods in Molecular Biology

A skeletal examination of fetuses is required in regulatory embryo-fetal development studies. This chapter describes a method of skeletal examination using alizarin staining. All fetuses are removed from the mother by caesarean section before birth. The fetuses are first examined externally. For larger species (rabbit and minipig), an internal examination can be performed on the fresh soft tissues by microdissection. For smaller species, such as the rat and mouse, half of each litter is fixed for internal soft tissue examination. The other half is used for skeletal examination. A rapid examination of the fresh soft tissues is performed before evisceration and fixation. The staining process takes several days. Following staining, all bones are examined from the head to the tail, in ventral and dorsal positions. © 2013 Springer Science+Business Media, LLC. Source

Allais L.,Ricerca Biosciences | Reynaud L.,Ricerca Biosciences
Methods in Molecular Biology

The rabbit is generally the non-rodent species or second species after the rat recommended by the regulatory authorities and is part of the package of regulatory reproductive studies for the detection of potential embryotoxic and/or teratogenic effects of pharmaceuticals, chemicals, food additives, and other compounds, including vaccines (see Chapters 1-7). Its availability, practicality in housing and in mating as well as its large size makes the rabbit the preferred choice as a non-rodent species. The study protocols are essentially similar to those established for the rat (Chapter 9), with some particularities. The study designs are well defined in guidelines and are relatively standardized between testing laboratories across the world. As for the rat, large litter sizes and extensive background data in the rabbit are valuable criteria for an optimal assessment of in utero development of the embryo or fetus and for the detection of potential external or internal fetal malformations. © 2013 Springer Science+Business Media, LLC. Source

Barrow P.C.,CiToxLAB | Reynaud L.,Ricerca Biosciences
Methods in Molecular Biology

The regulatory toxicology report is an unusual document that requires a particular skill to write. The report must be clear, accurate, concise, and focused. A clear and direct writing style is required. The end-users of the report will hope to find the information they seek with as little effort as possible. Few, or none, will read the entire document. The author should aim to appease the user by obliging him to read as little text and turn as few pages as possible. This chapter gives tips and guidance on how to present the experimental data and write the narrative text in the final study report for a teratology study. © 2013 Springer Science+Business Media, LLC. Source

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