Caracterização químico-bromatológica, digestibilidade e produção de gases de variedades de palma forrageira do gênero Opuntia

Abstract

The Brazilian Semiarid region annually undergoes long periods of drought that limit the production and quality of forage resources. Therefore, we have sought food that can be used as the food base of animals during periods of drought, such as forage palm, already widely used, especially in the dry season. The objective of this study was to evaluate the variation of the chemical-bromatological composition, carbohydrate fractions, digestibility and gas production in Opuntia (Opuntia ficus-indica Mill- IPA-20; Opuntia ficus-indica Mill-Gigante; Opuntia stricta Haw - Orelha de elefante mexicana; Opuntia undulata- Orelha-de-elefante Africana; Opuntia atropes Rose - F-08), associated with different phenological phases of the plant. The experiment was conducted in a completely randomized design, in a 5x3 factorial arrangement, five opuntia palm varieties and three phenological phases. Dry matter (DM), organic matter (OM), mineral matter (MM) crude protein (CP), ethereal extract (EE), neutral detergent fiber (NDF), acid detergent fiber (FDA), digested lignin in acid (LDA), and carbohydrate fractions. In the production of in vitro gases, the pressure generated by the fermentation was measured using a pressure transducer with a needle connection (0.06 mm). The readings were measured at times (2, 4, 6, 8, 10, 12, 15, 18, 21, 24, 30, 36, 42 and 48 h) after incubation. The cladodes of the Orelha de elefante mexicana and Orelha de elefante afrifricana varieties showed significantly (P<0.05) the highest values of MM (117.5 g/kg) and DM (111.5 g/kg). The lowest concentrations (P<0.05) of NDF were found in the cladodes of the Orelha de elefante mexicana varieties, with 146.7 g/kg MS at the young phase and 172g/kg MS at the intermediate phase and 310.7 g/kg MS for mature phase. In the Orelha de elefante mexicana and Orelha de elefante africana varieties, cladodes presented higher proportions of pectin in DM (P<0.05). The IPA-20 presented the highest values of total carbohydrates (P<0.05) in all the phenological phases of cladodes (young, 843.6, intermediate, 840.7 and mature, 856.6 g/kg MS). However, for non-fibrous carbohydrates and A+B fractions, the highest values (P<0.05) found in cladodes were found in the Orelha de elefante mexicana variety at all phenological phases (young phases, 819.5; 793.6 and mature, 626.1 g/kg of total carbohydrates). The cladodes of the Orelha de elefente mexicana and Orelha de elefante africana varieties contained the lowest values (P<0.05) of the C fraction. The higher gas volumes and gas production adjusted for the Bicompartmental model were found in cladodes of the cactus of Orelha de elefente adricana at all phenological phases (young = 313.2, intermediate = 325.5 and young 327.9 mL/gMS). In vitro digestibility, MS digestibilities were higher in cladodes of the Orelha de elefante mexicana, Orelha de elefante africana and F-08 clades, with greater evidence of young and intermediate phenotypes. Forage cactus varieties present a difference (P<0.05) in chemical composition, carbohydrate fractionation and volume of gas production, independent of the phenological stage of cladodes. All varieties present high in vitro dry matter digestibility.