Effects of nitrate and additional effect of probiotic on methane emissions and dry matter intake in Nellore bulls
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2010
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Este estudo foi realizado para avaliar a potencialidade do nitrato como componente na dieta para reduzir a produção de metano entérico. Estudos prévios acerca de ruminantes e nitrato focavam-se principalmente na toxicidade do nitrito observada aquando da incorporação de nitrato nas dietas.
Os animais receberam diferentes dietas em três diferentes períodos. A recolha de metano foi efectuada durante seis dias em cada animal e em cada período, utilizando a técnica do gás traçador SF6. Dezasseis animais (245 ± 13kg), submetidos a uma dieta neutra durante o primeiro período foram aleatoriamente distribuídos a um tratamento pela produção de metano por kg de matéria seca. No segundo período, a oito animais foi atribuída a dieta com ureia e aos restantes oito animais a dieta contendo nitrato (2,15% base MS). Durante o terceiro período, oito animais receberam uma dieta com nitrato e os outros oito animais, para além da dieta contendo nitrato, receberam 200 ml de probiótico (Megasphaera elsdenii).
No segundo período a produção diária de metano (g/dia) nos animais alimentados com a dieta de nitrato foi 41,6% mais baixo que nos animais que receberam a dieta com ureia (P<0,001). A dieta contendo o nitrato produziu menos metano expresso em g/kg de IMS (P<0,001). A produção de metano (% energia bruta ingerida) foi de 5,6% na dieta de ureia e 3,1% na dieta de nitrato, resultando numa redução de 41,1% com a dieta de nitrato quando comparado com a dieta de ureia (P<0,001). A ingestão de matéria seca não foi diferente entre os tratamentos (P>0,05).
No terceiro período, na dieta de nitrato com probiótico observou-se uma menor produção de metano (P<0.05). No entanto, não houve diferenças significativas entre os tratamentos, em relação às emissões de metano expressas em kg de matéria seca ou energia bruta ingerida (P>0,10). Além disso, não foram encontradas diferenças na ingestão de matéria seca (P=0.13).
Dados obtidos neste estudo mostraram que o nitrato tem uma grande potencialidade para reduzir as emissões de metano.
This study aimed to assess the potential of nitrate as a dietary component to reduce enteric methane productions. The main focus of previous researches with ruminants and nitrate was the toxic effect of nitrite, called methemoglobinemia. The animals were exposed to different diets in three different periods. Six days gas collections were completed for each bull in each of three collection periods using the SF6 tracer gas technique. Sixteen animals (245 ± 13kg), submitted to a neutral diet during the first period, were randomly allocated to a treatment blocked for methane emission per kg of DMI. Eight animals were allocated to a diet with urea and the others eight bulls to a nitrate diet (2.15% DM basis). During the third period, eight bulls received nitrate diet and the other eight bulls, beyond the nitrate diet, were drenched with 200 ml of probiotic (Megasphaera elsdenii). In the second period daily methane production (g/day) was 41.6% lower from bulls fed a nitrate diet than from bulls fed an urea diet (P<0.001). Nitrate diet produced less methane (expressed by g/kg of DMI) than urea diet (P<0.001). Methane production (% GEI) was 5.6% on urea diet and 3.1% on nitrate diet, resulting in a production of less 41.1% with nitrate diet compared with urea diet (P<0.001). The DMI was not different between treatments (P>0.05). In the third period the nitrate diet plus probiotic had a lower daily methane emissions (P<0.05). However there were no significant differences between treatments, when methane emission was expressed per kg DMI or GE intake (P>0.010). Furthermore no differences were found in DMI (P=0.13). Data obtained in this study showed that nitrate as a high potentiality to reduce methane emissions.
This study aimed to assess the potential of nitrate as a dietary component to reduce enteric methane productions. The main focus of previous researches with ruminants and nitrate was the toxic effect of nitrite, called methemoglobinemia. The animals were exposed to different diets in three different periods. Six days gas collections were completed for each bull in each of three collection periods using the SF6 tracer gas technique. Sixteen animals (245 ± 13kg), submitted to a neutral diet during the first period, were randomly allocated to a treatment blocked for methane emission per kg of DMI. Eight animals were allocated to a diet with urea and the others eight bulls to a nitrate diet (2.15% DM basis). During the third period, eight bulls received nitrate diet and the other eight bulls, beyond the nitrate diet, were drenched with 200 ml of probiotic (Megasphaera elsdenii). In the second period daily methane production (g/day) was 41.6% lower from bulls fed a nitrate diet than from bulls fed an urea diet (P<0.001). Nitrate diet produced less methane (expressed by g/kg of DMI) than urea diet (P<0.001). Methane production (% GEI) was 5.6% on urea diet and 3.1% on nitrate diet, resulting in a production of less 41.1% with nitrate diet compared with urea diet (P<0.001). The DMI was not different between treatments (P>0.05). In the third period the nitrate diet plus probiotic had a lower daily methane emissions (P<0.05). However there were no significant differences between treatments, when methane emission was expressed per kg DMI or GE intake (P>0.010). Furthermore no differences were found in DMI (P=0.13). Data obtained in this study showed that nitrate as a high potentiality to reduce methane emissions.
Descrição
Dissertação de Mestrado em Engenharia Zootécnica
Palavras-chave
Bovinos Nelore , Gases de efeito de estufa , Metano , Nitrato , Megasphaera , Nellore cattle , Greenhouse gas , Methane , Nitrate , Megasphaera elsdenii