Seven Angus-cross steers (475 lbs initial
body weight) were used in a 7 × 4 incomplete
Latin square experiment to evaluate the effects
of supplemental L-carnitine on nitrogen balance
and blood metabolites. Steers were fed the
same high-protein, corn-based diet near ad
libitum intake. Treatments were control and
.25, .5, 1.0, 1.5, 2.0, and 3.0 grams/day of
supplemental carnitine. Experimental periods
were 18 days with 13 days for adaptation and
5 days for collection of feces and urine. Blood
was collected at feeding and 3 and 6 hours after
feeding on day 18 of each period. Supplementing
steers with carnitine increased urinary carnitine
excretion and plasma carnitine concentration.
Nitrogen retention (a measure of protein
deposition) was not affected by carnitine
supplementation and averaged 29.3 g/d.
Plasma insulin and glucagon, indicative of energy
status, and cholesterol and triglyceride, representative
of energy storage metabolites, were
not affected by carnitine supplementation.
Plasma glycerol and beta-hydroxybutyrate,
reflective of fat catabolism, increased with
intermediate levels of supplemental carnitine. In
conclusion, carnitine supplementation did not
alter N balance in our experiment, but it did alter
some of the plasma metabolites of steers fed
high-protein, corn-based diets.
