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The effects of Saccharomyces cerevisiae-based products on the ruminal environment and performance of sheep submitted to dietary changes.

C. Brauner




The effects of Saccharomyces cerevisiae-based products on the ruminal environment and performance of sheep submitted to dietary changes.
L. Tavares, M. Ara�jo, J. Noschang, J. Halfen, A. Schmidt, A. Matos, M. Oll�, A. Barbosa, J. Feij�, C. Brauner*, M. Corr�a, E. Schmitt, F. Del Pino, V. Rabassa. N�cleo de Pesquisa, Ensino e Extens�o em Pecu�ria (NUPEEC), Universidade Federal de Pelotas Pelotas, RS, Brazil.

The increase in the use of energy foods in ruminant can trigger important metabolic disturbances, making the use of additives an effective strategy in modulating the ruminal environment with performance optimization. The aim of the study was to evaluate the effects of Saccharomyces cerevisiae in maintaining ruminal pH, performance and metabolism in sheep submitted to changes in the diet starch concentration. For this purpose, 20 adult female sheep were used in a confined system and randomized assigned to 1 of 3 treatments: no yeast (Control; n = 6), yeast culture (YC; n = 7) and hydrolyzed yeast (HY; n = 7) supplemented with 5g/sheep/day. The groups were submitted to 4 experimental periods of 5 d, varying the composition of the diet in 40 and 60% wheat bran and the remainder composed of roughage based on corn silage. The diet in periods 1 and 3 was composed by 40% of wheat bran and periods 2 and 4 by 60% of wheat bran on DM basis. Feed offered was adjusted to achieve 3% of BW. Blood, ruminal fluid and BW were evaluated at the end of each period and the DMI was recorded daily. Ruminal fluid was analyzed to determine the physical parameters, ruminal pH, bacterial activity through the methylene blue test and evaluation of the motility of the protozoa under an optical microscope immediately after collection. Data were analyzed using NCSS software and the averages were analyzed using the mixed models method. Although rumen pH was not affected (P > 0.05) by treatment, protozoan motility was more efficient in supplemented animals (P < 0.05). The DMI was not affected, however, there was a trend to increase the daily gain (kg/d) in YC group in comparison with control in the third period (0.47 vs. 0.11 � 0.26 kg) (P = 0.10). The HY showed an increase in total proteins (P < 0.01) in the last 2 periods in comparison with others, indicating a greater supply of available protein and a better adaptation to dietary changes, even with higher concentration of starch. The aspartate aminotransferase enzyme, an important indicator of liver damage, was greater (P < 0.01) in HY fed animals in the second period in comparison with control, which was maintained in the following period (97.7 vs. 80.1 � 6.6 U/L). Yeast supplementation seems to be a potential tool when diet changes are necessary, partially by improving the performance of confined sheep.

Keywords: yeast culture, ruminal modulation, starch.

Biography: Bachelor in Veterinary by Universidade Federal de Pelotas (2004), Masters degree in Animal Science (2007) and PhD in Animal Science by Universidade Federal de Pelotas (2011). Beef Cattle Specialist by the American Registry of Professional Animal Scientists (2010). Part of my doctorate was at University of Wyoming when I was a Researcher Scholar (2009-2010). My research foci are in ruminant nutrition, animal reproduction and metabolism of cattle and sheep. The research lines are in association with the Research group of NUPEEC (Center for Research, Education and Extension in Livestock) at Universidade Federal de Pelotas - Brazil