Dietary L-Carnitine Improves Nitrogen Utilization in Growing Pigs Fed Low Energy, Fat-Containing Diets

Abstract

Growing pigs (n = 25; 17.8 +/- 0.1 kg) were used to study the effects of L-carnitine and protein intake on nitrogen (N) balance and body composition. Fat-supplemented (40 g soy oil/kg diet), corn-soybean meal basal diets containing low or high protein (136 or 180 g/diet) were formulated so that protein accretion would be limited by metabolizable energy (ME). Each basal diet was supplemented with 0 or 500 mg/kg L-carnitine and fed to pigs for 10 d in a nutrient balance trial. Final body composition was compared with weight and age-matched pigs measured on d 0 to calculate nutrient accretion rates. High protein feeding increased (P < 0.01) average daily gain (ADG) by 34%, as well as nitrogen digestibility (4.4%), retention (5.2%), urinary excretion (29%) and crude protein (CP) accretion (33%). Total-body carnitine accretion rate was 4.5 fold greater and total body carnitine concentration was almost 100% greater than in unsupplemented controls (P < 0.01). Irrespective of protein level, carnitine increased ADG (by 7.3%, P < 0.10) and CP accretion rate (9%, P < 0.10). Congruently, carnitine supplementation improved the efficiency of nitrogen retention (P < 0. 05) and reduced urinary nitrogen excretion (14%, P < 0.10). Carcass fat content also was reduced in carnitine-supplemented pigs (P < 0. 10). Collectively, these data support the hypothesis that carnitine can improve the efficiency of nitrogen utilization in 20-kg pigs fed energy-limited, fat-containing diets. We conclude that endogenous carnitine biosynthesis may be adequate to maintain sufficient tissue levels during growth, but that supplemental dietary carnitine (at 500 mg/kg) may be retained sufficiently so as to alter nutrient partitioning and thus body composition of 20-kg pigs.

Reproductive Performance of Sows Supplemented with Dietary L-carnitine over Three Reproductive Cycles

“…It could be that increased concentrations of carnitine in plasma and tissues of piglets improves the utilization of nutrients. A recent study in pigs with 20 kg body weight showed that dietary L-carnitine improves the nitrogen retention (Heo et al, 2000). Further studies, however, are needed to ascertain whether such suggestions come true.…”

Effects of L-carnitine and iron diet supplementations on growth performance, carcass characteristics and blood metabolites in fattening pigs

“…In piglets and growing pigs, L-carnitine supplementation led to a reduction in body fat and an increase in body protein (Heo et al 2000, Owen et al 2001a, 2001b. This effect is due to an enhanced rate of β-oxidation of long-chain fatty acids.…”

Ontogeny and kinetics of carnitine palmitoyltransferase in liver and skeletal muscle of the domestic felid ()

“…De novo synthesis is inadequate in human neonates, resulting in low plasma carnitine concentrations in premature infants [10]. Therefore, dietary carnitine supplementation is advocated for infants and, similarly, may be beneficial for domestic livestock species [11][12][13]. Studies examining systemic carnitine distribution have shown that concentrations vary widely depending on age [14], tissue [15], physiological status [16], species [17] and dietary carnitine content [18].…”