Potencial de silagens a base de palma forrageira em dietas para ovinos no semiárido nordestino

Abstract

The objective of this study was to evaluate the nutritional value of silage composed of forage palm (Opuntia stricta Haw) associated with gliricidia (Gliricidia sepium), buffel grass (Cenchrus ciliaris) and porcupine (Manihot esculenta), as well as exclusively for forage palm (Opuntia stricta Haw) and corn silage (control treatment), through chemical and bromatological composition, fractionation of carbohydrates and nitrogen compounds, degradation parameters (DDM), digestibility (IVDDM) and in vitro gas production, as well as the consumption of dry matter and nutrients, water intake, dry matter and nutrient digestibility coefficients, performance parameters and nitrogen balance of lambs fed the different silages. The treatments were composed of palm silage associated with forages adapted to the semi - arid 60:40 ratio represented by palm and gliricidia silage, palm and buffel grass, palm and porcupine based on natural matter, as well as forage palm silage and silage of corn. After the 60 days period, the samples were collected in four replicates per treatment for analysis aiming to evaluate their nutritional values in the laboratory. In addition, the samples were tested using 40 mestizo Santa Inês sheep, male, uncastrated, with a mean age of six months and initial weight of 20.90 ± 0.27 kg, confined in individual stalls provided with feeder, drinker and salt shaker for 21 days, with 15 for adaptation of the animals to the bays, the diets and the water offers and 5 days for samples and data collection. The experimental design was the completely randomized (DIC) with five treatments and eight replicates. The highest values (P <0.05) in fraction A (soluble protein and non-protein nitrogen) were observed in the palm and maize silages. Although in most silages the highest fractionation content was found from the sum of B1 + B2 fractions (proteins with rapid and intermediate degradation in the rumen), with emphasis (P <0.05) on buffel grass palm silage. Palm and gliricidia silages and palm and porcine silages indicated higher available content in fraction B3 (proteins slowly degraded in the rumen). The potentially degradable fiber contained in fraction B2 presented higher levels in the silages composed of palm and gliricidia and corn. The carbohydrate types directly influence dry matter utilization, IVDDM and DDM in the palm and palm and buffelgrass silages were the highest and lowest respectively (P <0.05). The fermentation of the CHOt generated higher volumes of total gases (Vt1) and gases found from the bicompartmental logistic model (Vt2), in the palm and maize silages, however palm and gliricid silages and palm and porcine silages showed higher values than the palm silage and buffel grass in the two parameters. Experimentation in the lambs presented higher intakes (P <0.05) of DM with silages composed of palm and gliricid, and palm and buffel grass. PB consumption was higher in diets composed of palm silage and gliricidia and palm with pork. There was a difference (P <0.05) in drinking water intake, with lower values for diets with compound silages and for forage palm exclusive silage. In the dry matter and protein digestibility coefficient, it presented positive results for palm and gliricidia composed silages, palm and buffel grass silages. There was no difference (P> 0.05) for the parameters of mean total gain and mean daily gain. The nitrogen balance was higher (P <0.05) in the diets with palm silage and gliricidia. The results obtained in this study showed that silages based on forage palm have potential for use, with nutritional value and feeding of lambs in feedlot.