Evaluation of eleven Mexican cultivars of prickly pear cactus trees for possibly utilization as animal fed: in vitro gas production

In production systems of prickly pear fruit and prickly pear cactus, significant amounts of pruned material, which could be used as an ingredient in animal feeding, is generated. The aim of this study was to measure the nutrient content, fermentation kinetics and in vitro digestibility of eleven cultivars of cladodes of prickly pear cactus. The fermentation was measured indirectly using the gas production technique, where 500 mg of DM substrate (prickly pear cactus cultivars) were placed in amber glass flasks of 125 mL with 90 mL of ruminal inoculum under a continuous flow of CO2. Flasks were hermetically wrapped up with a rubber stopper and a metal ring, and were placed in a water bath at 39 C. The fermentation gas pressure was measured using a monometer at 0, 2, 4, 6, 8, 12, 16, 20, 24, 32, 38, 50 and 72 h incubation. Results show that the chemical composition ranged between (g kg-1 DM): 64 and 160 g kg-1 dry matter (DM), 137–293 g kg-1 DM ash, 52–101 g kg-1 DM crude protein, 3–22 g kg-1 DM ether extract, 251–393 neutral detergent fiber and 132–192 acid detergent fiber. The gas volume was different (p\0.05) among cultivars, with the Red Vigor cultivar having the largest volume at 378 mL g-1 DM. The highest volume of gas was produced during the first 24 h in on average 67 % of the total produced. The in vitro DM digestibility displayed values of up to 82 % in the Roja Pelota cultivar. It can be concluded that the cladodes of prickly pear cactus from different cultivars can be used in animal feed for its good rumen fermentation characteristics.

Key words: Fermentation, Gas production, Chemical composition, Prickly pear.

Abstract published in Agroforestry Systems. DOI 10.1007/s10457-016-9947-6.