Cinética ruminal de espécies forrageiras nativas da caatinga

Abstract

This study aimed at evaluating the kinetics of in situ ruminal degradation of the dry matter (DM), crude protein (CP) and neutral detergent fiber (NDF) of five local forage species from the semi-arid region of Paraiba (Brazil): “Orelha de Onca” (Macroptilium Martii Benth), “Amor de Vaqueiro” (Desmodium canum), “Feijao Bravo” (Capparis Flexuosa), “Manicoba” (Manihot Epruinosa) and “Imburana de Cambao” (Camniphora leptophloes). Four two-year-old male sheep, castrated, belonging to the breed Santa Ines, with an average weight of 40 kg, previously rumen-fistulated, were distributed in an entirely randomized statistical design, with subdivided portion. The animals were housed in individual stalls and fed ad libitum with diets containing hays of the studied forages and a mineral supplementation. The foods were ground, put into nylon bags and incubated during 0, 6, 12, 24, 48 and 96 hours. Chemical-bromatological analyses of the forages were carried out to determine in situ ruminal degradation. The solubility of DM was larger for “Feijao Bravo” hay. For the potentially degradable fraction of DM, "Manicoba" hay presented the highest average value. Compared to the other forages, "Manicoba" and “Feijao Bravo” hays showed the lowest percentage of the undegradable fraction (P <0,01), but the highest PD and ED (2-5%/h) of DM (P <0,01). “Feijao Bravo” hay presented the highest rates of PD and ED (2-5%/h) of CP. Among the forages examined, "Manicoba" and “Feijao Bravo” hays presented the best potential for feeding. The degradability in the DM, CP and NDF indicated the best potential of use for “Feijao Bravo” and "Manicoba", since the nutritional quality and efficiency of utilization in the rumen was higher for these forages.