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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

Percentage fertility on the natural logarithmic scale obtained from egg break-out from the batch of eggs incubated (Table 3) versus corresponding egg florfenicol concentration (n = 5) from the separate batch of eggs assayed by HPLC
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Fig3: Percentage fertility on the natural logarithmic scale obtained from egg break-out from the batch of eggs incubated (Table 3) versus corresponding egg florfenicol concentration (n = 5) from the separate batch of eggs assayed by HPLC

Mentions: Post-treatment egg concentration for the 90 mg/kg group was 4.27 ± 0.76 μg/g on day 1 and had declined to 0.85 ± 0.05 μg/g by day 5 post-0 mg/kg treatment (Table 4). The depletion was not linear for all the groups with the 30 and 60 mg/kg group showing an increase in concentration from 24 to 48 h, before starting to decline. When the percentage fertility was plotted against florfenicol egg concentrations, a linear relationship was present with linearity of >85 % (Fig. 3). The best fit equation was defined as y =-0.65× + 4.61, and an LC50 of 1.07 μg/g.Table 4


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

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

Percentage fertility on the natural logarithmic scale obtained from egg break-out from the batch of eggs incubated (Table 3) versus corresponding egg florfenicol concentration (n = 5) from the separate batch of eggs assayed by HPLC
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

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

Fig3: Percentage fertility on the natural logarithmic scale obtained from egg break-out from the batch of eggs incubated (Table 3) versus corresponding egg florfenicol concentration (n = 5) from the separate batch of eggs assayed by HPLC
Mentions: Post-treatment egg concentration for the 90 mg/kg group was 4.27 ± 0.76 μg/g on day 1 and had declined to 0.85 ± 0.05 μg/g by day 5 post-0 mg/kg treatment (Table 4). The depletion was not linear for all the groups with the 30 and 60 mg/kg group showing an increase in concentration from 24 to 48 h, before starting to decline. When the percentage fertility was plotted against florfenicol egg concentrations, a linear relationship was present with linearity of >85 % (Fig. 3). The best fit equation was defined as y =-0.65× + 4.61, and an LC50 of 1.07 μg/g.Table 4

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