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Nitrogen digestion and urea recycling in H okkaido native horses fed hay‐based diets
Author(s) -
Obitsu Taketo,
Hata Hiroshi,
Taniguchi Kohzo
Publication year - 2015
Publication title -
animal science journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.606
H-Index - 38
eISSN - 1740-0929
pISSN - 1344-3941
DOI - 10.1111/asj.12256
Subject(s) - urea , hay , digestion (alchemy) , ileum , soybean meal , dry matter , zoology , chemistry , feces , rumen , nitrogen balance , food science , fermentation , biology , biochemistry , nitrogen , microbiology and biotechnology , chromatography , raw material , organic chemistry
Nitrogen ( N ) digestion and urea‐ N metabolism in H okkaido native horses fed roughage‐based diets containing different types and levels of protein sources were studied. Horses (173 ± 4.8 kg) fitted with an ileum cannula were fed four diets consisting of 100% timothy hay ( TH ), 88% TH and 12% soybean meal ( SBM ), 79% TH and 21% SBM , and 51% TH and 49% alfalfa hay at 2.2% of body weight. Dietary protein content varied from 5% to 15% of dry matter. Apparent N digestibilities in the pre‐cecum and total tract for the TH diet were lower than those for other diets. However, the proportion of post‐ileum N digestion to N intake was not affected by the diets. Urea‐ N production was linearly related to N intake, but gut urea‐ N entry was not affected by the diets. The proportion of gut urea‐ N entry to urea‐ N production tended to be higher for the TH diet (57%) than the two SBM diets (39%). Anabolic use of urea‐ N entering the gut was not affected by the diets (20–36% of gut urea‐ N entry). These results indicate that urea‐ N recycling provides additional N sources for microbial fermentation in the hindgut of H okkaido native horses fed low‐quality roughages.