No abstract

O presente estudo foi conduzido com o objetivo de avaliar as perdas fermentativas, a composição bromatológica e a estabilidade aeróbica de silagens provenientes de diferentes genótipos de milho produzidos com adubação orgânica. Os quatro tratamentos, avaliados em delineamento inteiramente casualizado, foram compostos pelos diferentes genótipos de milho: 1) híbrido simples (HS); e três variedades: 2) IPR114; 3) IPR164; e 4) ZMG01. Sessenta dias após a ensilagem foram quantificadas as perdas fermentativas, os silos foram abertos e amostrados para avaliações bromatológicas e de estabilidade aeróbica. As variedades apresentaram menor (p≤ 0,05) recuperação da matéria seca (MS) ensilada do que HS e a variedade ZMG01 apresentou o menor (p≤ 0,05) valor de pH dentre os genótipos. Os silos produzidos com HS e IPR114 apresentaram maiores teores de MS e menores (p≤ 0,05) concentrações de fibra em detergente neutro do que os silos de IPR164 e ZMG01. A variedade IPR114 reduziu o pH da silagem nas avaliações realizadas 48 e 72 horas, e a temperatura nas avaliações realizadas entre 40 e 64 horas após a exposição aeróbica, em relação aos demais genótipos avaliados. As variedades avaliadas no presente estudo apresentam maiores teores de fibra e menor recuperação da MS, em relação ao HS. Dentre as variedades avaliadas, IPR114 minimiza as perdas fermentativas e produz silagem com menor teor de fibra e maior estabilidade aeróbica, sendo, dentre as variedades estudadas, a variedade mais recomendada para sistemas orgânicos de produção.

Lemongrass essential oil (LEO) has been evaluated as a silage additive to improve silage fermentation and reduce fermentative losses. The present study aimed to evaluate the effects of increasing levels of LEO on whole-plant sorghum silage (WPSS) fermentation profile, fermentation losses, chemical composition, dry matter (DM) and neutral detergent fibre (NDF) in vitro degradation and aerobic stability. Five cultivars and fifty experimental silos were used to evaluate the following LEO levels: 0, 1, 2, 3 and 4 ml kg−1 DM of WPSS. The material was compacted (650 kg m−2) and the silos were sealed, weighed and stored at room temperature for 167 days. The addition of LEO linearly decreased butyric acid content and the ratio between lactic and acetic acids. Intermediate levels of LEO increased NH3-N and reduced lactic and acetic acids content. LEO linearly decreased silage gas losses. However, LEO did not affect total silage losses and DM recovery. Intermediate levels of LEO addition decreased organic matter and crude protein in the WPSS. The addition of LEO did not affect other chemical composition parameters, DM and NDF in vitro degradation, and pH and temperature of the silage after aerobic exposure. Thus, LEO supply in WPSS reduces gas losses, butyric acid concentration, and the ratio between lactic and acetic acids. However, LEO does not improve the chemical composition, in vitro degradation, and aerobic stability of WPSS.

Context Ensiling is commonly used to conserve tropical grasses, but low water-soluble carbohydrates content and high moisture content in the grass impair silage fermentation characteristics. Essential oils may be used as silage additives to decrease fermentative losses and improve the nutritional value of silage, and aerobic stability, and in vitro DM disappearance. Aims The present study aimed to evaluate the effect of including lemongrass essential oil (LEO) on the fermentative characteristics, fermentative losses, chemical composition, in vitro disappearance and aerobic stability of Mombasa grass (Megathyrsus maximum) silage. Methods Mombasa grass was ensiled for 60 days in 32 experimental silos (15-L plastic buckets, 28 cm diameter and 25 cm high), in a randomly blocked design. LEO was included at 0.00, 0.67, 1.33 and 2.00 mL per kg of silage fresh matter. Silos were weighed every 15 days, pH and temperature were measured immediately after the silos were opened, and subsamples of silage were taken to measure the fermentative profile, composition of silage effluent, chemical composition and in vitro degradation of silage. Key results Increasing the amount of LEO in Mombasa grass silage caused a linear reduction in ammonia–nitrogen, ethanol (P < 0.05), acid detergent fibre of silage, gas losses and silage pH after aerobic exposure. There was no impact (P > 0.05) on organic acid concentration, effluent production or DM recovery (P > 0.05). Conclusions (Tilley and Terry 1963) Adding LEO to Mombasa grass silage at up to 2.00 mL per kg fresh material (almost 7.5 mL/kg DM) reduces gas losses, ammonia–nitrogen and acid-detergent fibre concentration, and silage pH after aerobic exposure. However, it is not sufficient to improve DM recovery and in vitro disappearance of silage. Implications Lemongrass essential oil shows a positive effect on Mombasa grass silage fermentation, fibre content and silage parameters after aerobic exposure, providing a useful additive in this silage.