Mucilagem de sisal (Agave sisalana, Perrine) ensilada para alimentação de caprinos e ovinos

Abstract

The Brazilian semiarid is the world's largest producer of sisal (Agave sisalana, Perrine). Although only up to 5% of the plant is used, causing an enormous amount of solid waste that is wasted or underused, which can be an important alternative source of forage for ruminants. However, the lack of knowledge about safe ways of conservation and its real nutritional importance for ruminants are very scarce. Thus, aiming to investigate the effect of additives (ground corn, wheat bran and cotton bran) on losses, microbiological dynamics, fermentative changes and quality of sisal defibration mucilage silages at different storage times, in addition to the effect of silages in the diet of goats and sheep, on nutrient intake and digestibility, ingestive behavior, water consumption, rumen dynamics, nitrogen balance, microbial protein synthesis, ruminal parameters and biochemical profile of blood and urine, two were conducted. experiments, at the Department of Animal Science of the Federal Rural University of Pernambuco. In experiment I, 60 experimental silos were used, distributed in experimental treatments consisting of silages of: sisal shredded mucilage (SilMUDS), MUDS ensiled with ground corn (SilMUDS-MI), MUDS ensiled with wheat bran (SilMUDS-FT), and MUDS ensiled with cottonseed meal (SilMUDS-FA). The silos were opened at 7, 14, 30, 60 and 120 days after ensiling. The additives (ground corn and wheat bran) were efficient in increasing the dry matter content compared to the control treatment, reducing losses due to the lower effluent production (P<0.0001), in addition to providing lower NH3-N production (P<0.0001) and increase the concentration of water-soluble carbohydrates (CSA), resulting in more effective fermentation with a consequent drop in pH (P<0.0001) during the fermentation process of the material. However, cottonseed meal had an opposite effect to the other additives, so that in SilMUDS-FA there was a higher production of N-NH3 (P<0.0001), as well as higher pH values (P<0.0001). In experiment II, four castrated male sheep and four goats with permanent rumen fistulas were used, with initial mean body weights (BW) of 71.05 ± 7.53 kg and 57.41 ± 9.71 kg, respectively. The animals were fed experimental rations composed of tifton 85 grass hay (Cynodon dactylon L.) and the silages in as roughage, concentrated feed (ground corn, soybean meal and wheat bran) and mineral mixture, formulated to be isonitrogenous. The additive silages showed higher consumption of MO (P=0.0383), CT (P=0.0260), CNF (P<0.0001), NDT (P=0.0018), DMS (P<0, 0001), BMD (P<0.0001), and DCT (P<0.0001), it should be noted that animals fed with SilMUDS-MI, due to its better quality, presented a higher observed value of Allantoin (mmol/L) (P=0.0278). The animals fed the control diet showed higher production of Acetic Acid (P=0.0013), whereas those fed the diets containing silages had higher values of Propionic Acid (P=0.0112). In general, the biochemical profile of the blood of goats and sheep were within the ranges proposed for the species. However, the goats presented a clinical picture compatible with nephropathy, presenting urinary flow obstruction by stones, which could be observed with the values of urea (306.25 to 483.639mg/dL) and creatinine (29.99 to 31.759mg/dL) from above the reference range for the species. It is concluded that the use of ground corn and wheat bran in the MUDS ensilage results in silages with a better fermentation pattern and lower losses. The use of SilMUDS added with ground corn or wheat bran in the diet of goats and sheep positively influences the intake and digestibility of dry matter and its constituents, does not interfere with the nitrogen balance, microbial protein synthesis and does not alter the biochemical profile of the blood. However, further studies are suggested in order to assess the possible antinutritional factors contained in sisal mucilage, especially on renal function, in order to safely include sisal mucilage in ruminant feeding, without compromising animal health, concomitantly the maximization of productive variables.