The role of pH on the survival of rumen protozoa in steers

Abstract

-In order to study the effect of pH on defaunation in the rumen, four rumen fistulated steers were fed a basal roughage diet for a 4-week adaptation period followed by 17 weeks of feeding with three diets and two feeding levels of high concentrate diet. Rumen outflow fluid rate was evaluated in both ration levels. Rumen protozoa population was monitored weekly and when animals became defaunated, protozoa were reinoculated with rumen contents from one of the faunated steers.At every two weeks, during all the experimental period, rumen pH was measured in all animals at 0, 4, 8 and 12 h after feeding.It was observed an individual animal influence on the establishment and maintenance of the rumen ciliate protozoa population.In all sampling times, mean rumen pH values were higher in faunated steers than in the defaunated ones. No differences were observed in rumen outflow fluid rates between the two ration levels. Extended periods of low rumen pH are probably more detrimental to the survival of ciliate protozoa in the rumen than other factors.Key Words: cattle, ciliate protozoa, rumen microorganism, ruminal fauna Importância do pH na sobrevivência de protozoários no rúmen de bovinos RESUMO -Com o objetivo de estudar efeito do pH sobre a defaunação no rúmen, quatro novilhos fistulados no rúmen foram alimentados com uma dieta basal com volumoso por um período de quatro semanas, seguido de 17 semanas com três dietas e dois níveis de alimentação com dieta rica em concentrado. A taxa de passagem do líquido ruminal foi avaliada em ambos os níveis de ração. A população de protozoários do rúmen foi monitorada semanalmente e, quando os animais se tornavam defaunados, protozoários eram reinoculados com conteúdo ruminal de um dos bovinos faunados. A cada duas semanas, durante todo o período experimental, o pH ruminal foi medido em todos os animais às 0, 4, 8 e 12 horas após a alimentação. Foi observada influência individual do animal sobre o estabelecimento e a manutenção da população de protozoários ciliados no rúmen. Em todos os tempos de amostragem, as médias de valores de pH ruminal nos animais faunados foram maiores que nos animais defaunados. Não foram observadas diferenças no rúmen na taxa de passagem do líquido ruminal entre os dois níveis de ração.Longos períodos de baixo pH no rúmen provavelmente são mais prejudiciais para a sobrevivência dos protozoários ciliados no rúmen que outros fatores.Palavras-chave: bovinos, fauna ruminal, protozoários ciliados, microrganismos rúmen Revista Brasileira de Zootecnia

A study on gastrointestinal tract characteristics of ram lambs at the same weights from six Turkish sheep breeds

“…The pH of the rumen content was higher (P <0.001) in TM and AK lambs compared with KY and MK lambs, while the caecum content pH of KV lambs was higher (P = 0.020) than those of KY and MK lambs. Rumen content pH typically ranged from 6.5 to 6.8, and most rumen microbes can only thrive in this type of environment (Franzolin & Dehority, 2010;. The pH values in the contents of all segments of the GIT obtained in the present study were within the values obtained by other researchers feeding high-energy diets.…”

Role of diverse fermentative factors towards microbial community shift in ruminants

“…Degradation of diets by rumen microbes can be said to be regimented due to their preference for different feed structures and substrates. Similarly, individual variation of animals plays an important role in deciding the rumen microbiome of ruminants even when fed similar diets (Franzolin and Dehority ; Kala et al . ), a condition that could probably be attributed to genetic difference.…”

“…Furthermore, when rumen microbes are assessed by culture-based techniques, it is often assumed that all the important microbes are discovered, and this frequent in some developing countries due to the lack of appropriate molecular equipment. However, molecular-based evaluation gives a more holistic approach in describing various functional groups of microbes and differences in the microbial diversity of complex ecosystems (Roesch et al 2007;Franzolin and Dehority 2010) and this gives us the opportunity to assess how microbes are largely influenced under different feeding and environmental conditions. Several reports used in this review have demonstrated that microbes in the gut change based on the diet they consume, but to the best of our knowledge, none has been able to summarize in addition to diet, the influence of pH on shift in microbial diversity and animal health.…”

Use of Jerusalem artichoke tops silage to replace corn silage in sheep diet

“…No significant effect of the dietary substituting JATS levels for CS on the total enumeration and generic composition of ruminal protozoa could be explained by the normal and similar rumen pH, which has an important contribution to the rumen protozoa population (Franzolin and Dehority, 2010). Additionally, it has been reported that the ruminal proportions of individual VFA, such as acetic and butyric acids, are associated with protozoa counts (Babayemi et al, 2004;Carberry et al, 2012).…”