CHEMICAL COMPOSITION AND PROPORTION OF PRECURSORS OF RUMENIC AND VACCENIC ACIDS IN ALTERNATIVE FORAGES FOR THE FEEDING OF RUMINANTS IN ARID ECOSYSTEMS

Abstract

The nutrimental value was determined of alfalfa hay (AH), two genotypes of cowpea [IT90K-277-2 (CG18) and Sesenteño (CG25)], a clone of Taiwan grass (TG), a local cultivar of prickly pear cactus in two presentations, green cladodes of 15 days of age or ";nopalitos"; (TN) and mature cladodes of 60 days of age (MN) and germinated seeds of maize (GM) of the genotype ASGROW 7573. The content of dry matter (DM), crude protein (CP), total lipids (TL), ash (A), crude fiber (CF) and gross energy (GE), as well as the concentration of linoleic acid (LA), α-linolenic acid (ALA), polyunsaturated fatty acids (PUFA) and n-3 fatty acid. Results reveal that CG25 and CG18 showed the highest content of CP. With respect to the concentration of TN, the genotype CG25 showed the highest amount followed by CG18 and AH. In turn, GM and TN showed the highest concentrations of LA; whereas the two genotypes of cowpea (CG18 and CG25) and TG, had the highest levels of ALA. The forages that obtained the highest concentrations of n-3 fatty acids were the two genotypes of cowpea (CG18 and CG25) and TG. These forages along with TN showed the highest concentration of PUFA. The green forages cowpea (CG25 y CG18), as well as taiwan grass, had the highest content of α-linolenic acid. Germinated seeds of maize showed the highest content of linolenic acid, followed by green cladodes. Both polyunsaturated fatty acids (ALA and LA) are precursors of rumenic acid and vaccenic acid in ruminants. Therefore, the use of these green forages in the feeding of ruminants is an alternative that could modify the proportions of the fatty acids of milk and meat for the purpose of increasing the PUFA, specifically, rumenic acid, as well as vaccenic acid.