Efeitos de enzimas fibrolíticas sobre a degradação in situ da matéria seca e da fibra de forrageiras

Abstract

Resumo: Embora ruminantes aproveitem fibras dos alimentos, a degradação varia de acordo com a composição físico-química. Enzimas fibrolíticas tem sido utilizadas para aumentar a degradação ruminal de fibras, podendo otimizar o aproveitamento dos nutrientes. O objetivo deste estudo foi avaliar o efeito da enzima fibrolítica xilanase e de um blend enzimático contendo xilanase, celulase e glucanase, em alimentos volumosos: feno de alfafa (Medicago sativa), capim-Braquiária (Urochloa ruziziensis syn Brachiaria ruziziensis) cana-de-açúcar (Saccharum officinarum), capim-Mombaça (Megathyrsus maximus syn Panicum maximum cv. Mombaça) e silagem de milho (Zea mays). O delineamento experimental foi inteiramente casualizado com 5 repetições (vacas), para cada tratamento. Os tratamentos consistiram em uma pré-incubação por 12 horas em tampão de McDougall: 1) sem a adição de enzimas (CT); 2) com a adição de 200 mg/kg de matéria seca (MS) de amostra (XI); e com a adição de 200 mg kg -1 de MS de amostra (BL). Após a aplicação dos tratamentos, as amostras dos alimentos foram incubadas no rúmen das vacas, por 96 horas. O capim-Mombaça apresentou maiores degradações da MS e FDN que as demais forrageiras avaliadas. A xilanase tendeu a aumentar a degradação da fibra em detergente ácido (FDA) em relação ao controle. O blend enzimático aumentou a degradabilidade da MS e FDN, em relação ao CT e tendeu a aumentar a degradação da MS e da FDN em relação à XI. A adição do blend enzimático aumenta a degradação da MS e FDN, sendo uma estratégia enzimática recomendada na dieta de ruminantes.Palavras-chave: digestão ruminal, fibra em detergente neutro, incubação , xilanase Abstract: Although ruminants could utilize fiber of feeds, the degradation varies according to it physicochemical composition. Fibrolitic enzymes have been used to increase ruminal degradation of fibers, and can optimize the use of nutrients. The objective of this study was to evaluate the effect of the xylanase fibrolytic enzyme and an enzymatic blend containing xylanase, cellulase and glucanase in roughage: alfalfa hay (Medicago sativa), Brachiaria grass (Urochloa ruziziensis syn Brachiaria ruziziensis) sugarcane (Saccharum officinarum), Mombasa grass (Megathyrsus maximus syn Panicum maximum cv. Mombasa) and corn silage (Zea mays). The experimental design was completely randomized with 5 replicates (cows), for each treatment. Treatments consisted of a pre-incubation for 12 hours in McDougall's buffer: 1) without the addition of enzymes (CT); 2) with the addition of 200 mg xilanase per kg dry matter (DM) of sample (XI); and with the addition of 200 mg of enzymatic blend per kg sample MS (BL). After application of the treatments, the feed samples were incubated in the rumen of cows for 96 hours. Mombasa grass presented higher DM and NDF degradations than the other evaluated forages. The xylanase tended to increase the degradation of the acid detergent fiber (ADF) in relation to the control. The enzymatic blend increased degradation of DM and NDF in relation to the CT and tende...

Nutritional value, fermentation losses and aerobic stability of elephant grass (Pennisetum purpureum Schum.) silage treated with exogenous fibrolytic enzymes

“…For the levels of ADF, a quadratic effect was found, where the level of 4.5% fibrolytic enzymes resulted in the lowest value observed, reaching 449.9 g.kg -1 DM. These results are in line with Antonio et al (2018), who observed increased in situ NDF degradation of Mombasa grass silage (Panicum maximum Jacq. Cv.…”

“…Mombaça) treated with a blend of fibrolytic enzymes (xylanase, cellulase and glucanase). These results are in line with Antonio et al (2018), who observed an increase in in situ NDF degradation of the Mombasa grass silage (Panicum maximum Jacq. Cv.…”

“…This is probably because in the control treatment there were more favorable conditions for gas-producing bacteria, such as enterobacteria and the genus Clostridium (Furtado, Carneiro, Coutinho, Cândido & Silva, 2019). However, these results differ from those reported by Del Valle et al (2018), who observed no significant effect of fibrolytic enzymes on gas losses in silages of sugarcane (Saccharum officinarum L. RB02-5799).…”

Supplementation of yeast culture combined with an enzyme complex in the diet for confined steers

“…When exogenous enzymes are administered, they enter into synergy with bacterial enzymes, thus enhancing their effects ( 31 ). Fibrolytic enzymes promote hydrolysis and greater degradation of polysaccharides present in the food cell wall, which generates greater degradation and consequently greater use of the diet and consequently reduces fecal output ( 32,33,34 ).…”