ABSTRACT. Reducing livestock negative environmental impacts get great interest in last years. So, present study was carried out to determine the effect of adding different levels of mixture of thyme and celery versus salinomycin on ruminal fermentation, gas production, dry, organic matter and fiber degradation. Four experimental treatments were used by in-vitro batch culture technique, as follow: 60% CFM, 40% clover hay (control), control diet + 2.5 gm thyme + 2.5 gm celery kg-1 DM (T1), control diet + 5 gm thyme + 5 gm celery kg-1 DM (T2), control diet + 10 gm thyme + 10 gm celery kg-1 DM (T3), control diet + 0.4 gm Salinomycin kg-1 DM (T4). Ruminal pH value was significantly increased (p < 0.05) with T4 compared with other treatments. While, the T4 recorded the lowest value (p < 0.05) for microbial protein, short chain fatty acids concentrations (SCFA), total gas production, dry matter and organic matter degradability (DMd and OMd) compared with other treatments. Fiber fraction degradability (NDFd and ADFd) appeared no significant variance (p > 0.05) between control and other treatments except for T1 that recorded the lowest value (p < 0.05). It is concluded that mixture of thyme plus celery could be alternate for ionophores in the ruminant diets to enhance ruminal fermentation, reducing gas production without any negative effect on nutrients degradability.

RESUMO. Este estudo teve como objetivo avaliar as folhas de palmeiras sozinhas ou suplementadas com enzimas fibrolíticas, como uma alternativa de degradação da fibra na digestibilidade de nutrientes de ruminantes e produção de gás. Os tratamentos foram: Feno (Trifolium alexandrinum), folhas de palmeiras, e folhas de palmeiras com adição de enzimas fibrolíticas (as enzimas foram misturadas com a folha com taxa de 4g kg-1 matéria seca (MS). Os resultados mostraram uma redução da produção de gás (p < 0.05), nitrogênio amoniacal (NH3-N), MS e matéria orgânica (MO) na digestibilidade das folhas da palmeira comparadas com o feno. Enquanto a suplementação de folhas com as enzimas fibrolíticas, aumentou a digestibilidade DM e OM comparado com as folhas de palmeira, que não teve diferenças com o feno (p < 0.05). Também, suplementando as folhas de palmeiras com as enzimas fibrolíticas reduziram em (p < 0.05) a produção de gás comparado com os outros tratamentos. Pode ser concluído que a adição das enzimas fibrolíticas aumenta a utilização da folha da palmeira como uma alternativa de forragem a qual não possui efeitos negativos na digestibilidade de nutrientes e reduz a produção de gás, a qual melhora os aspectos dos meios da alimentação de animais ruminantes.

ABSTRACT. This study was carried out to evaluate using palm fronds only or supplemented with fibrolytic enzymes as alternative roughage on the ruminal nutrients digestibility and gas production. Treatments were: clover hay (Trifolium alexandrinum), palm fronds only and palm fronds plus fibrolytic enzymes (enzymes were mixed with palm fronds in rate of 4 g kg-1 of dry matter (DM). The results showed a reduction (p < 0.05) in gas production, ammoniac nitrogen (NH3-N, DM and organic matter (OM) digestibility in palm fronds compared with clover hay. While supplementing palm fronds with fibrolytic enzymes improved DM and OM digestibility compared with palm fronds only without (p < 0.05) differences with clover hay. Also, supplementing palm fronds with fibrolytic enzymes reduced (p < 0.05) gas production compared with other treatments. It could be concluded that adding fibrolytic enzymes improved the utilization of palm fronds as alternative roughage without negative effect on nutrients digestibility and reduced gas production which improve the environmental aspects of feeding ruminant animals.