ABSTRACT
OBJECTIVE: To obtain information on the toxicity of lufenuron on the reproduction ability and the growth and development of offspring in female and male rats through two-generation reproduction toxicity study. METHODS: The specific pathogen free healthy SD rats were randomly divided into control group and low-, medium-and high-dose lufenuron groups, with 60 rats in each group, half females and half males. Rats in the low-, medium-and high-dose lufenuron groups were respectively fed with lufenuron at the dose of 5.0, 20.0 and 80.0 mg/(kg body weight·day) for 8 weeks before mating. The control group was fed with standard foot. The reproductive index, brain and reproductive organ coefficients and pathological changes were observed in P and F1 parents. The birth and growth indexes of the offspring were measured. RESULTS: i) P generation: from the 14 th day, the female rats in the medium-dose group had lower body weight than that of the female control group(P<0.05); from the 35 th day, the body weight was lower than that of the female low-dose group(P<0.05). From the 14 th day, the female rats in the high-dose group had lower body weight than that of the other three female groups(P<0.05). From the 14 th day, the male rats in the medium-and high-dose groups had lower body weight than that of the male control group and low-dose group(P<0.05). The body weight of pregnant rats in the parental high-dose group was lower than that of the control group, low-dose group, and medium-dose group at day 0, 7, 14, 19 of the pregnancy duration(P<0.05). The body weight of pregnant rats in the parental medium-dose group was lower than that of the low-dose group on day 0 of the pregnancy duration, and lower than that of the control and low-dose groups on day 7 and 14(P<0.05). The conception rate, the new-borne survival rates and the feeding survival rate of female rats in the high-dose group was lower than that of the other three female groups(P<0.008). The new-borne feeding survival rate of female rats in the medium-dose group was lower than that of the control group and low-dose group(P<0.008). The organ coefficients of brain in female rats in the medium-and high-dose groups were higher than that of the female control group and low-dose group(P<0.05). The organ coefficients of brain and testis in male rats in the medium-and high-dose groups were higher than that of the control group and low-dose group(P<0.05). The organ coefficient of epididymis in male rats in the high dose group was lower than that of the other three male groups(P<0.05). ii) F1 generation: the body weight of female rats in the low-and medium-dose group was higher than that of the female control group on the 42 th day(P<0.05). The body weight of male rats in the low-dose group was higher than that of the male control group on the 42 th, 49 th, and 56 th days(P<0.05). The body weight of male rats in the medium-dose group was higher than that of the male control group on the 14 th, 21 th, 42 th, 49 th, and 56 th days(P<0.05). The new-borne survival rate in the low-dose group was lower than that of the control group(P<0.017). The body weight of new-borne rats in the high-dose group on day 4 of birth was lower than that in the other three female groups(P<0.05). iii) F2 generation: the body weight of male rats in the male medium-dose group was lower than that in the control group on day 21 of birth(P<0.05). CONCLUSION: The reproductive and developmental toxicity of lufenuron is found in rats in the medium-and high-dose groups. Toxicities including low body weight, conception rate, new-borne survival rate and feeding survival rate are found in P generation; low body weight and feeding survival rate are found in F1 generation; low body weight is found in male F2 generation. The no-observed-adverse-effects levels of lufenuron in two-generation reproductive study are 5.87 mg/(kg·d) for females and 5.09 mg/(kg·d) for males in SD rats.
ABSTRACT
The effect of the chitin synthesis inhibitor lufenuron on the various developmental stages of red flour beetle Tribolium castaneum was determined by exposing them to different sub-lethal concentrations (LC10, LC20 and LC40) of lufenuron through diet for 24 hrs. There was a dose dependent effect on the larval weight, time taken for pupation, and adult emergence, percentage pupation and percentage adult emergence. When two day old larvae were fed on sublethal concentrations through diet a small proportion of pupal –adult intermediates were observed at LC20 and LC40. Adults emerging from the larvae fed on diet containing LC10, LC20 and LC40 of lufenuron did not show any variation in the fecundity and hatchability of eggs from that of control. The fecundity of adults fed with sub-lethal concentration of lufenuron (obtained against two day old larvae through diet) was not affected, however, percentage hatching and survival was affected. Interestingly there was a reversal of the effect within ten days of treatment with respect to percentage hatching and survival. When eggs were exposed to treated diet hatching was not affected. The present data suggest that lufenuron even at sub-lethal concentrations has a very good larvicidal and ovicidal activity in T. castaneum.
ABSTRACT
Due to discrepancies regarding the effectiveness of lufenuron in treating dermato-phytosis caused by Microsporum canis the effect of this drug was checked in 46 cats (30 with cutaneous lesions and 16 asymptomatic carriers) treated in the Veterinary Hospital of the Federal Rural University of Rio de Janeiro, Brazil. The diagnosis was based on Wood's lamp examination and fungal cultures. Biopsies were only performed in symptomatic animals. The animals were treated with lufenuron (120mg/kg every 21 days), for 4 times. The drug was efficient in 29 of the 30 affected felines and as well as in all of the asymptomatic carriers. The cat that did not respond, had received several dexameta-zone doses prior to the treatment with lufenuron. The drug was given to one animal during the first stages of pregnancy and no abnormalities or neonatal disorders were found in any of the kittens. None of the treated animals showed side effects. Twenty days after the last administration of lufenuron, 45 of the studied animals (98 percent) had negative fungal culture. The cost of treating dermatophytosis with lufenuron is a little higher than with ketoconazole, but the drug has some advantages regarding its practicability and security.The correct drug prescription and animal's medication as well as environmental decontamination are very important for the success of the treatment.
Em função de controvérsias sobre a eficácia do lufenuron no tratamento da dermatofitose causada por Microsporum canis, o efeito da droga foi avaliado em 46 gatos (30 com lesões cutâneas e 16 portadores assintomáticos) atendidos no Hospital Veterinário da Universidade Federal Rural do Rio de Janeiro, Brasil. O diagnóstico foi estabelecido através da lâmpada de Wood, da cultura fúngica e, adicionalmente, na maioria dos animais sintomáticos, pela avaliação histopatológica da pele. Os animais foram tratados com 120mg/kg de lufenuron, a cada 21 dias (quatro doses); a droga mostrou-se eficaz no tratamento de 29 dos 30 felinos que apresentaram a forma clínica da dermatofitose, bem como no de todos os animais assintomáticos. O único felino que não teve cura clínica completa havia recebido várias doses de dexametasona antes do inicio do tratamento. Em um animal gestante, foram utilizadas duas doses do lufenuron e não foi observada qualquer alteração clínica e morfológica nos filhotes. Nenhum dos animais tratados teve qualquer reação adversa ao medicamento. Vinte dias após o último tratamento, o exame micológico resultou negativo em 45 dos felinos estudados (98 por cento). Embora o lufenuron tenha o custo um pouco mais elevado do que o do cetoconazol, é uma droga que apresenta praticidade e margem de segurança bem maiores. Vale ressaltar que o sucesso do tratamento está diretamente relacionado à correta utilização da droga, assim como a perfeita higienização do ambiente e dos utensílios dos animais.