Indução e transferência de resistência a intoxicação por Palicourea marcgravii (Rubiaceae) em ovinos

• Autor(a) principal: Carneiro, Faber Monteiro
• Data de Publicação: 2013
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da UFMT
• Texto Completo: http://ri.ufmt.br/handle/1/1136
• topic: Palicourea marcgravii; Intoxicação por planta; Monofluoracetato de sódio; Ovinos; Morte-súbita; CNPQ::CIENCIAS AGRARIAS::MEDICINA VETERINARIA; Palicourea marcgravi; Intoxication by plant; Sodium monofluoroacetate; Ovine; Sudden death

Palicourea marcgravii contains sodium monofluoroacetate (MF) and is the main plant associated with the “sudden death” in cattle in Brazil. The toxic dosage of fresh leaves for bovine and ovine is of 0.6g/kg. Studies have demonstrated the existence of ruminal microorganisms, in soil and in plants, capable of degrading the MF. The aim of this study is to verify if ovine become resistant to the consumption of P. marcgravii after repeated administration of non-toxic doses and if this resistance can be transferred to susceptible ovine by transfaunation of ruminal contents. The induction of resistance was performed by supplying daily doses of 0.03 g/kg of dried and crushed leaves of P. marcgravii for 20 days to a group of sheep (G1). After the induction period, the ovine were challenged with four different doses of P. marcgravii at intervals of 15 days each: 0.06 g / kg for 10 days, 0.12 g / kg for 5 days 0.2 g / kg for 3 days and single dose of 0.6 g / kg. After the first G1 challenge, each 24 hours, 100ml of the ruminal liquid was collected from the ovine of G1, by esophageal catheter and immediately transferred to the other ovine group (G2) which was submitted to same challenges like G1. The criteria for evaluation of resistance were heart rate, intensity of symptoms and clinical outcome compared with Control Groups (GC-3 dose of 0.12 g / kg for 5 days, GC4 dose of 0.2 g / kg for 3 days and for GC5 single dose of 0.6 g / kg). The G1 and G2 groups showed mostly discrete clinical signs while the control groups were moderate and severe. In the challenge of 0,12g/kg the GC-3 showed cardiac frequency average of 176±59, while G1 and G2 showed 134±41 and 140±41, respectively. In the challenge of 0,2g/kg the cardiac frequency of GC-4 was 176±56 over G1 with 167±46 and G2 with 155±52. In the last challenge all the ovine from GC-5 had cardiac frequency average of de 199±136 and died, while in G1 the cardiac frequency showed was 169±49 and in the G2 161±57 and all survived. The challenge with a single dose of 0.6 g / kg caused the death of three sheep in the control group. However the 5 sheep from the transfauned group and the two sheep which remaining from resistant group did not die. The present study showed that resistance to poisoning by P. marcgravii can be stimulated by repeated dose of a non-toxic plant. This resistance can be transferred by transfaunation of rumen contents of sheep resistant to non-resistant sheep. These methods indicate that the poisoning resistance of P. marcgravii occurs possibly due to the existence of mixed ruminal bacteria that degrades monofluoroacetato.