Inclusão de diferentes materiais genéticos de Cana-de-açúcar (Saccharum officinarum) na alimentação de equinos

Abstract

The aim of this project was to evaluate genetic materials of sugar cane as only roughage source in horse nutrition. The trials were performed at Universidade Federal Rural do Rio de Janeiro (UFRRJ), Campus Seropédica. Eight Mangalarga Marchador adult gelding horses with average age of 6,5 years were used. A 4x4 duplicate and simultaneous latin square analysis were used. The treatments were sugar cane genetic materials: RB867515, RB058046, RB098022 and RB969017. Each experimental period would have 26 days, totalizing 104 days of trial. However, at the end of the adaptation period of sugar cane intake as exclusive roughage four animals had colic. Thus, the study was changed. In the first chapter, the feces physicochemical characteristics and its application to prevent colic cases were evaluated. The evaluations were realized as follows: 1° - after elephant grass; adaptation; 2° - after 30% sugar cane consumption; 3° - after 60% sugar cane consumption; 4° - after of 100% sugar cane consumption. The following variables were evaluated: length, width, height, weight, volume, density, dry matter, pH, structure and color of the feces. Decrease in pH and fecal ball size, thus increase of DM due to enhance of sugar cane diet inclusion were observed. These alterations were due the high content of non-fibrous carbohydrates (NFC) and lignin in its composition. Intake over 1,41%BW of sugar cane as exclusive roughage were observed in animals that developed colic. The second chapter, the aim was to evaluate the sugar cane genetic materials nutritive value through a semiautomatic in vitro gas production technique. Three animals were used as fecal inoculum donors. A randomized block arrangement with repeated measures on split-plot design was used. The treatments were the genetic materials RB867515, RB058046, RB098022, RB969017, coast-cross hay and elephant grass. The subplot was the incubation time of 24 and 48 hours. The dry matter degradation (DMD), cumulative gas production (CGP) and pH in 24 and 48 hours were evaluated. The CGP was adjusted by a bicompartmental mathematic model with the following parameters: Maximum volume of gas production from soluble nutrients (Vf1); fermentation rate of soluble nutrients (C1); Lag phase (L); Maximum volume of gas production from non-soluble nutrients (Vf2); fermentation rate of non-soluble nutrients (C2). High values of DMD, CGP for sugar cane in comparison of the feed coast-cross hay and elephant grass were observed. Low values of sugar cane pH were observed. No significant differences in the sugar cane genetic materials of model parameters were observed. Moreover, sugar cane presented superior vf1 and vf2 values compared to coast-cross hay and elephant grass. In general, the sugar cane is a food with high concentration NFC which stimulate DM consumption. However, the high lignin content makes it contraindicate as exclusive roughage for horse diet