RESUMO -Objetivou-se nesta pesquisa avaliar os efeitos de dois níveis de fibra em detergente neutro (FDN) da dieta (25 e 35%), provenientes de duas proporções de volumoso/concentrado (50:50 e 60:40), sobre a digestibilidade dos nutrientes, o pH fecal e os parâmetros sangüíneos de lactato, glicose, uréia, creatinina e fosfatase alcalina, visando estabelecer os níveis mínimos e seguros de fibra em dietas para eqüinos. Utilizaram-se cinco eqüinos sem raça definida, com 6 a 8 anos de idade e peso médio de 300 kg, alojados em gaiolas próprias para estudos de metabolismo. Os animais foram distribuídos em delineamento de quadrado latino 5 × 5, composto de cinco tratamentos (dois níveis de FDN, 25 e 35%, duas relações volumoso:concentrado, 50:50 e 60:40, e uma dieta controle, com relação 50:50 volumoso:concentrado) e cinco períodos. Cada período experimental teve duração de 15 dias (10 de adaptação e 5 de coleta de fezes e sangue e determinação do pH fecal). Os níveis de FDN utilizados neste experimento (25 e 35%) reduziram a digestibilidade dos componentes fibrosos (fração parede celular) da dieta, entretanto, não influenciaram os níveis sangüíneos de lactato, glicose, uréia, creatinina e fosfatase alcalina e o pH fecal. A dieta com 25%de FDN promoveu alteração no teor plasmático de fibrinogênio, portanto, pode aumentar a predisposição dos animais a quadros de laminite e cólica. Palavras-chave: digestibilidade, glicose, lactatoNeutral detergent fiber levels in diet of equines ABSTRACT -The objective of this research was to evaluate the effects of two levels of neutral detergent fiber (NDF) of the diet (25 and 35%) from two forage to concentrate (50:50 and 60:40) ratio on nutrient digestibility, fecal pH and blood parameters as lactate, glucose, urea, creatinine, fibrinogen and alkaline phosphatase, to establish minimum and safe levels of fiber in equines diets. Five horses without defined race, with 6 to 8 years old and average 300 kg BW, were housing in metabolism cages. The animals were distributed to 5 × 5 Latin square design, composed of five diets (two levels of NDF, 25 and 35%, two forage to concentrate ratio, 50:50 and 60:40, and a control diet, with 50:50 forage to concentrate ratio, and five periods.Each period lasted 15 days (10 of adaptation and 5 for collection of feces and blood and pH fecal determination). Neutral detergent fiber levels (25 and 35%) reduced the fiber components digestibility (cell wall fraction) of the diet, however, did not influence the levels of blood parameters as lactate, glucose, urea, creatinine and alkaline phosphatase and fecal pH. Diet with 25% of NDF promoted change in fibrinogen plasma level, therefore, may increase the susceptibility of animals to colic and laminitis problems.Key Words: digestibility, glucose, lactate IntroduçãoOs eqüinos apresentam anatomia e fisiologia digestiva adaptada para se alimentarem exclusivamente de forragens (herbívoros). Qualquer programa de alimentação que negligencie os níveis de fibra na dieta pode ter conseqüên-cias indesejáveis sobre a fisio...

-The objective of this study was to develop an economically optimal plan for pasture production and supplementary feeding of horses. The plan was based on the optimization of a multiperiodic linear programming model with the objective of minimizing overall feeding costs, subject to the nutritional constraints of each horse category. The model encompasses a period of one year, from January to December, divided in bimonthly periods. Technical coefficients varied among periods based on local information regarding productivity of the forage crops, taking into account the local climatic conditions and seasonality of production. Literature data on feed nutritional value (crude protein and digestible energy), dry matter intake and nutritional requirements of the horses were also used as technical coefficients. Optimization results allow concluding that it is possible to reduce significantly the feeding costs in the horse production system by decreasing supplementation and substituting the commercial concentrate by the oat grain produced in the local.Key Words: linear programming, modeling, ration balancing Planejamento otimizado da alimentação em um sistema de produção de equinos em pastejo RESUMO -Objetivou-se planejar e otimizar economicamente a produção de forragem e a alimentação de equinos, visando reduzir os custos de um sistema de produção de equinos em pastejo. O planejamento foi desenvolvido a partir da otimização de um modelo de programação linear multiperiódico com o objetivo de reduzir as despesas com alimentação, sujeita às restrições de exigência nutricional de cada categoria. O modelo contemplou o período de um ano, de janeiro a dezembro, dividido em bimestres. Os coeficientes técnicos variaram entre períodos com base em informações locais sobre a produtividade dos cultivos forrageiros e valores nutricionais dos alimentos (proteína bruta e energia digestível) sugeridos na literatura, considerando as condições climáticas e a sazonalidade de produção, observados na Coudelaria. De acordo com os resultados, é possível reduzir os custos no sistema de produção de forragem e na alimentação de equinos, bem como substituir o uso de concentrado comercial por aveia produzida no local.Palavras-chave: balanceamento de dieta, modelagem, programação linear Revista Brasileira de Zootecnia

This research was carried out to evaluate the effect of mycotoxins on the performance of horses through physiological parameters, and hematology and serum biochemistry analyses. The essay lasted 40 days, with 12 days for adaptation and 28 days of experimentation. In the experimental stage, the horses were distributed in a completely randomized design, with three treatments with four animals each. The treatments used were 0 (control), 50 ppb and 100 ppb of Aflatoxin B1 (AFB1) added to a concentrate in a basal diet. The basal diet contained mycotoxins from feedstuffs naturally contaminated. The exercise test was performed over the 21th day of the experimental stage. The exercise consisted in an interval training test with a warm-up of 17 mins at a trot followed by three gallops of 450m/min. The heart rate was monitored between the gallops. Before the exercise test and immediately after the third gallop, the physiological and blood parameters were evaluated, and continued up to 48 hours after the exercise. The results of the physiological, hematological and biochemical parameters were submitted to analysis of variance (ANOVA) and compared by the Tukey test at 5% of significance. The presence of AFB1 in the diet influenced the alkaline phosphatase activity, which presented higher values in horses fed diet with inclusion of 100 ppb AFB1, suggesting a hepatotoxic activity associated with the others mycotoxins naturally present in the feedstuffs.

The aim of this research was to evaluate the effect of mycotoxins on the digestion of nutrients and on the hematological profile of horses. Twelve horses were used in a completely randomized design, with three treatments and four replicates. Aliquots of 50 or 100 µg kg-1 of aflatoxin B1 (AFB1) were added to a basal diet naturally containing mycotoxins. The basal diet did not contain AFB1. The 40-day evaluation included a 12-day adaptation period and a 28-day experimental period. A digestion test was carried out at the end of the experimental period, using the partial stool collection method, using LIPE® as an indicator. Blood samples were collected once a week during 4 weeks of the essay for hematological and biochemical evaluations. The amounts of mycotoxins added did not influence the intake and digestibility of the nutrients (P>0.05). The aflatoxins in the diet influenced the white blood cell count, especially mature neutrophils and the creatine kinase and alkaline phosphatase (P <0.05), which had higher activity in horses fed diets with greater toxicity.