The effect of exogenous phytase supplementation on nutrient digestibility, ruminal fermentation and phosphorous bioavailability in Rambouillet sheep

Laura Haydee Vallejo, German Buendía, Mona Mmy Elghandour, Daniel Menezes-Blackburn, Ralf Greiner, Abdelfattah Zm Salem

Research output: Contribution to journalArticlepeer-review


BACKGROUND: The effect of phytase supplementation with respect to a high sorghum grain diet on sheep voluntary feed intake, apparent nutrient digestibility, ruminal fermentation, phosphorus (P) excretion and blood serum P concentration was evaluated.

RESULTS: Phytase supplementation significantly decreased fecal P excretion (P = 0.003), resulting in a 26% decrease in relation to the phytase free diet. Dry matter intake, nutrient digestibility, ruminal butyrate and serum P were not (P > 0.10) affected by the phytase level. Neutral detergent digestibility showed a tendency to increase linearly (P = 0.10) with increasing phytase levels. Ruminal pH was lower for phytase supplemented sheep, with a significant decrease (P = 0.007) at 9 h post feeding, whereas ruminal ammonia-N at 3 h post feeding was lower (P = 0.004) for the phytase treatment groups, resulting in a decreasing linear response (P = 0.001) with an increasing phytase dose. Duodenal pH was significantly reduced at 6 h post feeding. Propionate tended (P = 0.051) to be increased linearly as the phytase supplementation level increased.

CONCLUSION: Exogenous phytase supplementation of high sorghum grain diets significantly decreased fecal P excretion in Rambouillet rams. Phytase supplementation appears to affect neutral detergent fiber digestibility, duodenal and ruminal pH, ammonia and propionate. © 2018 Society of Chemical Industry.

Original languageEnglish
Pages (from-to)5089-5094
Number of pages6
JournalJournal of the Science of Food and Agriculture
Issue number13
Publication statusPublished - Oct 2018


  • 6-Phytase/administration & dosage
  • Ammonia/metabolism
  • Animal Feed/analysis
  • Animals
  • Biological Availability
  • Dietary Fiber/metabolism
  • Dietary Supplements/analysis
  • Feces/chemistry
  • Fermentation
  • Phosphorus/blood
  • Rumen/metabolism
  • Sheep/metabolism
  • Sorghum/metabolism

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