Intestinal digestibility of protein of adapted forages and by-products in Brazilian Northeast by three-steps technique

Abstract

It was aimed to estimate the intestinal digestibility (ID) of rumen-undegradable protein (RUDP) of several feeds by a three-steps procedure. The evaluated forages were algaroba (Prosopis juliflora), canafístula (Pithecellobium multiflorum), flor-de-seda (Calotropis procera), jitirana (Ipomea sp.), juazeiro (Ziziphus joazeiro), mata-pasto (Senna obtusifolia), sabiá (Mimosa caesalpiniaefolia Benth), palma gigante (Opuntia ficus indica) and xique-xique (Cereus gounellei), and the agroindustry byproducts were pineapple (Ananas comosus L.), barbados cherry (Malpighia emarginata), cashew (Anacardium occidentale), coconut (Cocos nucifera L.), melon (Cucumis melo), passion fruit (Passiflora eduli), grape (Vitis labrusca) and anatto seeds (Bixa orellana L.). The feeds were incubated in rumen during 16 hours to determine the RUDP, and the residue was submitted to the digestion with pepsin solution during one hour, and pancreatic solution during 24 hours at 38ºC, those residues were analyzed for total nitrogen. The estimative of RUDP forage ranged from 13.37 to 83.6%, and the RUDP by-product ranged from 39.14 to 89.06%. The intestinal digestion of RUDP of the forages ranged from 26.09 to 80.68%, while for by-products varied from 22.26 to 76.82%. The sabiá was the forage that presented the highest intestinal digestibility and digestive rumen-undegradable protein (RUDPd), and the flor-de-seda, the lowest digestibility; while for by-products, melon and cashew presented, respectively, the highest values for DI and RUDP. The coconut presented the lowest values for ID and RUDPd. Although, some formulation systems of diets for ruminant consider that the RUDP present constant ID, the data obtained in this work suggest variation among the different feeds.