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The effect of replacing nonstructural carbohydrates with soybean oil on the digestibility of fibre in trotting horses
Author(s) -
Jansen W. L.,
Kuilen J.,
Geelen S. N. J.,
Beynen A. C.
Publication year - 2000
Publication title -
equine veterinary journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.82
H-Index - 87
eISSN - 2042-3306
pISSN - 0425-1644
DOI - 10.2746/042516400777612008
Subject(s) - hay , starch , dry matter , food science , horse , chemistry , zoology , rumen , soybean oil , fermentation , biology , paleontology
Summary The hypothesis tested was that the intake of extra fat at the expense of an isoenergetic amount of nonstructural carbohydrates reduces fibre utilisation in horses. In a crossovertrial with feeding periods of 42 days each, 6 mature trotting horses (age 4–12 years, bodyweight 340–476 kg) were given either a control or test diet. The test concentrate was formulated to contain 37% of net energy in the form of soybean oil. The control concentrate contained an isoenergetic amount of corn starch plus glucose. The concentrates were fed in combination with the same amount of hay so that the control and test diet contained 25.13 and 86.66 g crude fat/kg dry matter, respectively. Apart from the amounts of fat and nonstructural carbohydrates, the 2 diets were identical. The test diet reduced the apparent total tract digestibilities of crude fibre, neutral and acid detergent fibre by 8.0 (P = 0.007), 6.2 (P = 0.022) and 8.3 (P = 0.0005) percentage units, respectively. It is suggested that a high fat intake by horses may increase the amount of fat entering the large intestine to levels that depress fermentation by cellulolytic bacteria. The observed interaction between fat content of the diet and fibre utilisation may have consequences for practical horse feeding in that calculating the energy content of test diets on the basis of feedstuff tables leads to overestimating the amount of energy provided by the high‐fibre ingredients of the diets.