Eliminacija kloramfenikola u kalifornijskoj pastrvi

Chloramphenicol muscle residue levels in rainbow trout were determined after oral administration of 84 μg kg−1d−1 of chloramphenicol for four days. Samples were taken one day before treatment and for 43 days after the treatment was over. Chloramphenicol was analysed using an in-house enzyme linked immunoassay (ELISA) validated against the criteria of the Commission Decision 2002/657/EC. Validation parameters confi rmed that the method was appropriate for the detection of chloramphenicol at levels below the minimum required performance limit (MRPL) of 0.3 μg kg−1. The highest chloramphenicol levels were observed on the fi rst day after the treatment had ended (144.3 μg kg−1). Elimination was signifi cant over the fi rst seven days; signifi cant differences were detected between days 1 and 3 (p<0.001), 3 and 5 (p<0.001), and 5 and 7 (p<0.05). Chloramphenicol levels dropped below MRPL to 0.17 μg kg−1 on day 9 after the end of treatment. From day 11 to 43, chloramphenicol residues were detectable in a range from 0.091 μg kg−1 (highest) to 0.011 μg kg−1 (lowest). Our results indicate that trout muscle tissue could be compliant with health requirements for consumption 10 days after withdrawal from chloramphenicol treatment.Određivani su ostaci kloramfenikola u mišićnom tkivu kalifornijske pastrve nakon oralne primjene u dozi od 84 μg kg−1d−1 tijekom 4 dana. Uzorkovanje je provedeno dan prije tretmana te tijekom 43 dana nakon tretmana. Maseni udjeli kloramfenikola određivani su primjenom in-house imunoenzimske metode (ELISA) validirane prema kriterijima Odluke Komisije 2002/657/EC. Dobiveni validacijski parametri pokazuju da je metoda prikladna za određivanje kloramfenikola na nivou manjem od vrijednosti granice najmanje zahtijevane učinkovitosti izvedbe metode (MRPL) od 0,3 μg kg−1. Najviši maseni udjeli kloramfenikola utvrđeni su prvog dana nakon završetka tretmana (144,3 μg kg−1). Statistički značajna eliminacija utvrđena je tijekom sedam dana te je značajno smanjenje određeno između prvog i trećeg (p<0,001), trećeg i petog (p<0,001) te petog i sedmog dana nakon tretmana (p<0,05). Razina kloramfenikola ispod MRPL vrijednosti utvrđena je devetog dana (0,17 μg kg−1) nakon tretmana. U vremenu od 11. do 43. dana nakon tretmana određeni su ostaci kloramfenikola od maksimalno 0,091 μg kg−1 do minimalno 0,011 μg kg−1. Prikazani rezultati pokazuju da se 10 dana nakon završetka tretmana tkivo pastrve može smatrati prikladnim za konzumaciju bez potencijalne štete za zdravlje

Clinical mastitis in ewes; bacteriology, epidemiology and clinical features

<p>Abstract</p> <p>Background</p> <p>Clinical mastitis is an important disease in sheep. The objective of this work was to identify causal bacteria and study certain epidemiological and clinical features of clinical mastitis in ewes kept for meat and wool production.</p> <p>Methods</p> <p>The study included 509 ewes with clinical mastitis from 353 flocks located in 14 of the 19 counties in Norway. Clinical examination and collection of udder secretions were carried out by veterinarians. Pulsed-field gel electrophoresis (PFGE) was performed on 92 <it>Staphylococcus aureus </it>isolates from 64 ewes.</p> <p>Results and conclusion</p> <p><it>S. aureus </it>was recovered from 65.3% of 547 clinically affected mammary glands, coagulase-negative staphylococci from 2.9%, enterobacteria, mainly <it>Escherichia coli</it>, from 7.3%, <it>Streptococcus </it>spp. from 4.6%, <it>Mannheimia haemolytica </it>from 1.8% and various other bacteria from 4.9%, while no bacteria were cultured from 13.2% of the samples. Forty percent of the ewes with unilateral clinical <it>S. aureus </it>mastitis also had a subclinical <it>S. aureus </it>infection in the other mammary gland. Twenty-four of 28 (86%) pairs of <it>S. aureus </it>isolates obtained from clinically and subclinically affected mammary glands of the same ewe were indistinguishable by PFGE. The number of identical pairs was significantly greater than expected, based on the distribution of different <it>S. aureus </it>types within the flocks. One-third of the cases occurred during the first week after lambing, while a second peak was observed in the third week of lactation. Gangrene was present in 8.8% of the clinically affected glands; <it>S. aureus </it>was recovered from 72.9%, <it>Clostridium perfringens </it>from 6.3% and <it>E. coli </it>from 6.3% of the secretions from such glands. This study shows that <it>S. aureus </it>predominates as a cause of clinical ovine mastitis in Norway, also in very severe cases. Results also indicate that <it>S. aureus </it>is frequently spread between udder halves of infected ewes.</p

Prions in Milk from Ewes Incubating Natural Scrapie

Since prion infectivity had never been reported in milk, dairy products originating from transmissible spongiform encephalopathy (TSE)-affected ruminant flocks currently enter unrestricted into the animal and human food chain. However, a recently published study brought the first evidence of the presence of prions in mammary secretions from scrapie-affected ewes. Here we report the detection of consistent levels of infectivity in colostrum and milk from sheep incubating natural scrapie, several months prior to clinical onset. Additionally, abnormal PrP was detected, by immunohistochemistry and PET blot, in lacteal ducts and mammary acini. This PrPSc accumulation was detected only in ewes harbouring mammary ectopic lymphoid follicles that developed consequent to Maedi lentivirus infection. However, bioassay revealed that prion infectivity was present in milk and colostrum, not only from ewes with such lympho-proliferative chronic mastitis, but also from those displaying lesion-free mammary glands. In milk and colostrum, infectivity could be recovered in the cellular, cream, and casein-whey fractions. In our samples, using a Tg 338 mouse model, the highest per ml infectious titre measured was found to be equivalent to that contained in 6 µg of a posterior brain stem from a terminally scrapie-affected ewe. These findings indicate that both colostrum and milk from small ruminants incubating TSE could contribute to the animal TSE transmission process, either directly or through the presence of milk-derived material in animal feedstuffs. It also raises some concern with regard to the risk to humans of TSE exposure associated with milk products from ovine and other TSE-susceptible dairy species

Principles of Mastitis Treatment in Sheep and Goats

This article indicates the principles for treatment of mastitis in ewes/does and explains the reasons why treatment may occasionally fail. It presents the principles for administration of antimicrobial agents at drying off of the animals. Finally, it addresses the risk of antimicrobials present in milk when improper withdrawal periods are used and the issues around testing for inhibitors before putting the milk into in a farm's tank