Effect of Levels of Sodium DL-malate Supplementation on Ruminal Fermentation Efficiency of Concentrates Containing High Levels of Cassava Chip in Dairy Steers |
S. Khampa, M. Wanapat*, C. Wachirapakorn, N. Nontaso, M.A. Wattiaux, P. Rowlison |
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Correspondence:
M. Wanapat, |
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Abstract |
Four rumen-fistulated dairy steers were randomly assigned according to a 4횞4 Latin square design to investigate effects of supplementation levels of sodium dl-malate in concentrates on rumen ecology, ruminal fermentation, nitrogen balance, feed intake and digestibility of nutrients and ruminal microbial protein synthesis. The dietary treatments were cassava concentrate-based, containing sodium dl-malate supplementation at 0, 9, 18 and 27 g/hd/d with urea-treated rice straw (UTS) fed ad libitum. The experiment was conducted for four periods, each period lasting 21 days. Ruminal pH increased with incremental addition of malate (p<0.05). Additionally, molar proportions of propionate were higher in supplemented groups and was highest at 18 g/hd/d of malate supplement (p<0.05). Microbial protein synthesis tended to be higher in dairy steers receiving sodium dl-malate supplements and also was the highest at 18 g/hd/d. Variable bacterial populations, such as amylolytic, proteolytic and cellulolytic species were increased (p<0.05). Furthermore, protozoal populations were decreased significantly (p<0.05), while fungal zoospores were dramatically increased in dairy steers receiving sodium dl-malate supplement (p<0.05). These results suggested that supplementation of concentrate containing a high level of cassava chip at 18 g/hd/d with UTS in dairy steers could improve rumen fermentation efficiency and rumen microbial protein synthesis. |
Keywords:
Sodium DL-malate; Rumen Fermentation; Microbial Protein Synthesis; Urea-treated Rice Straw; Dairy Steers; Ruminant |
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