Inoculação de silagem de capim-elefante com microrganismos do trato digestório de bovinos

Abstract

Elephant grass is used in the production of silage to supply animals when food is scarce, but it is susceptible to deterioration by undesirable microorganisms during fermentation. The objective of the work was to evaluate the inoculation of Lactobacillus plantarum and of the fungal species Aspergillus terreus and Trichoderma longibrachiatum from the bovine digestive tract in the ensiling of elephant grass (Pennisetum purpureum cv. Cameroon). Two experiments were carried out. In the first, two concentrations of L. plantarum in the silage of prewilted elephant grass and fermented in Falcon tube were evaluated. In the second experiment it was evaluated the inoculation of the fungi A. terreus, T. longibrachiatum and the mix of both fungi in the concentrations of 105 colony forming units per gram (CFU / g) on the aerobic stability and bromatological and microbiological composition of the fermented silage in PVC mini-silks. The different inoculations and ways of preserving forage showed different results. The inoculation of L. plantarum did not influence the losses of dry matter and effluent, the pH and the microbiological community of the silage fermented in Falcon tube, however it reduced the population of enterobacteria and caused the absence of non-fermenting lactose bacteria. On the other hand, it was verified that the inoculation of A. terreus and T. longibrachiatum positively affected the levels of neutral detergent fiber and non-fibrous carbohydrates, the aerobic stability of the silage and the community of microorganisms at the time of opening and after 10 days aerobic exposure of silage. The MIX silage was the most stable after aerobic exposure, but the control silage, A. terreus and T. longibrachiatum showed lower losses of dry matter (P <0.05). The treatments did not affect the levels of mineral matter, crude protein and ether layer (P > 0.05). Despite this, the silage inoculated with MIX presented a higher concentration of fibers and a lower content of non-fibrous carbohydrates than that inoculated with T. longibrachiatum. Only the final pH of the MIX silage assumed a value above 4.2 considered for good fermentation. There was an effect of the type of inoculation in the population of Diplococcus in the opening of silage and rods, Lactobacillus and total lactic acid bacteria after 10 days of aerobic exposure. In conclusion, the inclusion of A. terreus alone or in a mixture with T. longibrachiatum improves the aerobic stability of the silage, but increases the neutral detergent fiber content and reduces the non-fibrous carbohydrate content.