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Florfenicol induces early embryonic death in eggs collected from treated hens.

Al-Shahrani S, Naidoo V - BMC Vet. Res. (2015)

Bottom Line: Treatment of only the cockerels had no effect on egg hatchability, while treatment of only the hens at doses of 60 and 90 mg/kg resulted in decreased hatchability of 0 % in comparison to 70 % of the control as early 24 h after treatment.In all cases, decreased hatchability was associated with embryonic death at 5 days of development.The toxic effects of florfenicol were completely reversible with comparable hatchability being present by day 4 post-treatment withdrawal.

View Article: PubMed Central - PubMed

Affiliation: Department of Paraclinical Sciences, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort, 0110, South Africa. SMShahrane@sfda.gov.sa.

ABSTRACT

Background: Florfenicol, a commonly used veterinary antibiotic, was reported to have caused a severe drop in egg hatchability following its off-label use on a broiler breeder farm in South Africa. According to the pharmacovigilance report, hatchability dropped by 80 % for up to a week following a five day course at 10 mg/kg (both males and females treated metaphylactically) to manage an Escherichia coli infection. While mammalian toxicity studies indicate the potential for early embryonic death in utero or testicular damage, no literature is available on the avian toxicity of florfenicol. For this study we investigated the effects of florfenicol at various doses from 10 to 90 mg/kg on the egg hatchability in a breeder flock we kept and established under controlled conditions, with the same cockerels and hens being exposed in a phased manner.

Results: Following five days of oral exposure, no toxic signs were evident in any of the cockerels or hens treated at doses up to 90 mg/kg. Treatment of only the cockerels had no effect on egg hatchability, while treatment of only the hens at doses of 60 and 90 mg/kg resulted in decreased hatchability of 0 % in comparison to 70 % of the control as early 24 h after treatment. In all cases, decreased hatchability was associated with embryonic death at 5 days of development. The toxic effects of florfenicol were completely reversible with comparable hatchability being present by day 4 post-treatment withdrawal. Toxicity correlated with total egg florfenicol concentrations with an LC50 of 1.07 μg/g.

Conclusion: Florfenicol appears to be toxic to the developing chick embryo at around day 5 of incubation, in the absence of related toxicity in the hen or cockerel.

No MeSH data available.


Related in: MedlinePlus

Chromatogram for the 10 μg/ml sample, with the thiamphenicol internal standard
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Fig1: Chromatogram for the 10 μg/ml sample, with the thiamphenicol internal standard

Mentions: In phase 3, eggs collected on days 1 to 5 after treatment withdrawal were randomly collected from each group for quantification of their florfenicol concentrations using a modified method of Varma [3]. Eggs were cracked, shells discarded and the yolk/albumin homogenised. Two grams of egg homogenate in natural proportions were mixed with 100 μl of 10 μg/ml thiamphenicol (internal standard) and 9 ml ethyl acetate, vortexed and subsequently centrifuged at 2000 × g for 15 min. The resulting supernatant was decanted into a new tube, dried off for 30 min at 60 °C under a stream of nitrogen, prior to being mixed with 2 ml high pure water (MilliQ) and 2 ml hexane and re-centrifuged at 2000 × g for 15 min. For final extraction the supernatant was subjected to solid phase extraction (Varian BondElut C18) on cartridges primed with 4 ml methanol, followed by 4 ml MilliQ50 water. After the sample loading, a second wash was performed using 2 ml MilliQ50 water after which the cartridge was allowed to dry under vacuum for 5 min. Final elution was with 3 ml methanol under vacuum for 5 min. The eluent was dried under a stream of nitrogen for 30 min at 60 °C, prior to being reconstituted in 500ul of 30 % acetonitrile in reverse osmosis water (mobile phase) of which 100 μl was injected onto the column [Phenomenex guard cartridges (AJO-4287) and LG reverse phase, Luna 5μaC18 (2); 100A; 150 × 4.6 mm] under isocratic flow of 1 ml/min. Detection was via diode array on a Beckman HPLC at 223 nm (Fig. 1).Fig. 1


Florfenicol induces early embryonic death in eggs collected from treated hens.

Al-Shahrani S, Naidoo V - BMC Vet. Res. (2015)

Chromatogram for the 10 μg/ml sample, with the thiamphenicol internal standard
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4538914&req=5

Fig1: Chromatogram for the 10 μg/ml sample, with the thiamphenicol internal standard
Mentions: In phase 3, eggs collected on days 1 to 5 after treatment withdrawal were randomly collected from each group for quantification of their florfenicol concentrations using a modified method of Varma [3]. Eggs were cracked, shells discarded and the yolk/albumin homogenised. Two grams of egg homogenate in natural proportions were mixed with 100 μl of 10 μg/ml thiamphenicol (internal standard) and 9 ml ethyl acetate, vortexed and subsequently centrifuged at 2000 × g for 15 min. The resulting supernatant was decanted into a new tube, dried off for 30 min at 60 °C under a stream of nitrogen, prior to being mixed with 2 ml high pure water (MilliQ) and 2 ml hexane and re-centrifuged at 2000 × g for 15 min. For final extraction the supernatant was subjected to solid phase extraction (Varian BondElut C18) on cartridges primed with 4 ml methanol, followed by 4 ml MilliQ50 water. After the sample loading, a second wash was performed using 2 ml MilliQ50 water after which the cartridge was allowed to dry under vacuum for 5 min. Final elution was with 3 ml methanol under vacuum for 5 min. The eluent was dried under a stream of nitrogen for 30 min at 60 °C, prior to being reconstituted in 500ul of 30 % acetonitrile in reverse osmosis water (mobile phase) of which 100 μl was injected onto the column [Phenomenex guard cartridges (AJO-4287) and LG reverse phase, Luna 5μaC18 (2); 100A; 150 × 4.6 mm] under isocratic flow of 1 ml/min. Detection was via diode array on a Beckman HPLC at 223 nm (Fig. 1).Fig. 1

Bottom Line: Treatment of only the cockerels had no effect on egg hatchability, while treatment of only the hens at doses of 60 and 90 mg/kg resulted in decreased hatchability of 0 % in comparison to 70 % of the control as early 24 h after treatment.In all cases, decreased hatchability was associated with embryonic death at 5 days of development.The toxic effects of florfenicol were completely reversible with comparable hatchability being present by day 4 post-treatment withdrawal.

View Article: PubMed Central - PubMed

Affiliation: Department of Paraclinical Sciences, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort, 0110, South Africa. SMShahrane@sfda.gov.sa.

ABSTRACT

Background: Florfenicol, a commonly used veterinary antibiotic, was reported to have caused a severe drop in egg hatchability following its off-label use on a broiler breeder farm in South Africa. According to the pharmacovigilance report, hatchability dropped by 80 % for up to a week following a five day course at 10 mg/kg (both males and females treated metaphylactically) to manage an Escherichia coli infection. While mammalian toxicity studies indicate the potential for early embryonic death in utero or testicular damage, no literature is available on the avian toxicity of florfenicol. For this study we investigated the effects of florfenicol at various doses from 10 to 90 mg/kg on the egg hatchability in a breeder flock we kept and established under controlled conditions, with the same cockerels and hens being exposed in a phased manner.

Results: Following five days of oral exposure, no toxic signs were evident in any of the cockerels or hens treated at doses up to 90 mg/kg. Treatment of only the cockerels had no effect on egg hatchability, while treatment of only the hens at doses of 60 and 90 mg/kg resulted in decreased hatchability of 0 % in comparison to 70 % of the control as early 24 h after treatment. In all cases, decreased hatchability was associated with embryonic death at 5 days of development. The toxic effects of florfenicol were completely reversible with comparable hatchability being present by day 4 post-treatment withdrawal. Toxicity correlated with total egg florfenicol concentrations with an LC50 of 1.07 μg/g.

Conclusion: Florfenicol appears to be toxic to the developing chick embryo at around day 5 of incubation, in the absence of related toxicity in the hen or cockerel.

No MeSH data available.


Related in: MedlinePlus