Resumo O presente estudo foi realizado na microrregião de Ilhéus-Itabuna, Bahia. Os objetivos deste estudo foram determinar a soroprevalência de anticorpos contra Sarcocystis neurona em equinos da microrregião Ilhéus-Itabuna (BA) e identificar possíveis fatores associados à infecção. A presença de esporocistos/oocistos de Sarcocystis spp. também foi pesquisada em Didelphis spp. Foram coletadas 669 amostras de soro de equinos em 56 propriedades localizadas em 12 municípios da região. Foi utilizada a reação de imunofluorescência indireta (RIFI), utilizando-se lâminas confeccionadas com merozoítos de Sarcocystis neurona (cepa SN138) e ponto de corte na diluição de 1:80. A ocorrência de anticorpos anti- S. neurona, nos equinos amostrados, foi de 7,92%. As finalidades dos animais - comércio e trabalho - apresentaram-se significativas (p<0.05), sendo que a finalidade trabalho (21,6%) foi considerada fator de risco, enquanto a finalidade comércio (3,6%) foi considerada fator de proteção. Foram capturados 25 Didelphis spp., para pesquisa de esporocistos/oocistos em amostras de fezes e raspado de mucosa intestinal. Todos os Didelphis spp. foram negativos para a presença de Sarcocystis spp., mesmo assim essa circunstância não alterou o fato da ocorrência de S. neurona ter sido observada em cavalos criados na mesorregião do sul da Bahia.

Abstract The aims of this study were to determine the seroprevalence of Sarcocystis neurona antibodies in equines in the Ilhéus-Itabuna microregion (BA), and identify possible factors associated with infection. The presence of sporocysts/oocysts of Sarcocystis spp. was also verified in Didelphis spp. A total of 669 serum samples were collected from equines in 56 properties located in 12 municipalities in the region. Indirect fluorescent antibody test was performed with slides containing merozoites of the S. neurona, using a cut-off titer of 1:80. Occurrence of 7.92% of anti-S. neurona antibodies was observed in the sampled equines. The purposes trade and work were significantly associated with the presence of antibodies (p<0.05), and being used for the purpose of work (21.6%) was considered a risk factor, while being used for the purpose of trade (3.6%) was a protective factor. A total of 25 Didelphis spp. was captured for research on sporocysts/oocysts in stool samples and intestinal scrapings, being all negative. Didelphis spp. were all negative for the presence of Sarcocystis spp. and this circumstance does not change the fact that seroprevalence of S. neurona has been observed in horses raised in the southern Bahia.

The objectives of this experiment were to estimate the endogenous excretion of purine derivatives (PD), the intake and digestibility of nutrients, the urinary excretion of PD from the intake of total digestible nutrients (TDN) and digestible organic matter (DOM) in Nellore heifers. Eight heifers, 267±17 kg body weight (BW), were assigned to two 4 × 4 latin squares. The planned treatments were four dry matter intake (DMI) levels: 10, 14, 18 and 22 g/kg BW. The diet contained 70% corn silage and 30% concentrate. The endogenous losses were obtained by regression between excretion of PD (mmol/BW0.75) and DMI (g/BW0.75). When PD excretion (mmol/d) was related to the intake of DOM and TDN (kg/d), the following equations were obtained: ŶPD= 32.98 + 21.94*DOM and ŶPD= 32.47 + 20.40*TDN, respectively. The excretion of PD (mmol/d) was a function of DMI (kg/d): ŶPD = 0.605 + 0.014 x (r² = 0.46), and 0.60 mmol/BW0.75 was the endogenous fraction of PD. The endogenous losses of PD and nitrogen compounds obtained when the animals were fasted for 5 d, with free access to water, were 0.332 mmol/BW0.75 and 0.384 gN/BW0.75, respectively. The net protein requirement for maintenance was estimated at 2.4 g/BW0.75. Creatinine excretion is not affected by feed restriction.