Nutrient evaluation and in vitro digestibility of prickly pear cactus (Opuntia strepthacanta) and agave flowers (agave spp.) using Cellulase for goats

Due to diverse climate characteristics in Mexico there are large arid and semiarid areas, especially in the Northern part of the country, thus the production of forage and grain for livestock is complicated. Prickly pear cactus has been used for a long time as an emergency fodder like agave flowers in times of drought and winter. Prickly pear cactus and agave plants contain large amounts of water, carbohydrates and fiber, but a limited protein content, therefore addition of protein ingredients, and enzymes such as cellulase may increase the nutritional values and digestibility. Therefore the objectives of this study were to determine the nutritional quality and in vitro digestibility of prickly pear cactus and agave flowers diets treated with cellulase enzyme. Prickly pear cactus and agave flowers were collected and chemical analyzes were performed. The in vitro digestibility of these materials were done at different incubation times 0, 3, 6, 12, 24, 48, and 72 h. In vitro digestibility of dry matter, was analyzed with a completely randomized model with a 4×7 factorial arrangement, with four treatments at different incubation times, where treatments consisted of the same amounts of cactus and agave, t1=cactus+urea, t2=agave+urea, t3=cactus+cellulose and t4=agave+cellulase. The results of the nutrient analysis indicated higher ash, crude fiber, ADF and NDF contents for prickly pear cactus than for agave flowers, while agave flowers showed higher dry matter and protein contents than prickly pear cactus. The higher digestibility (P<0.05) was found for t4 diets (74.28%), followed by t1 (67.56%) and t3 (67.18%) which were not different between them, and the lower for t2 (63.15%) which was different to all treatments. In vitro digestibility was greater for treatments with the enzyme. Therefore it is recommended that the cellulose enzyme be used in diets with agave as it showed a more effective degradation. Animal performance data should be further collected to corroborate the in vitro results.