Effect of dietary L-carnitine on growth performance and body composition in nursery and growing-finishing pigs.

Abstract

Two experiments were conducted to determine the effect of dietary L-carnitine on growth performance and carcass composition of nursery and growing-finishing pigs. In Exp. 1,216 weanling pigs (initially 4.9 kg and 19 to 23 d of age) were used in a 35-d growth trial. Pigs were blocked by weight in a randomized complete block design (six pigs per pen and six pens per treatment). Four barrows and four gilts were used to determine initial carcass composition. L-Carnitine replaced ground corn in the control diets to provide 250, 500, 750, 1,000, or 1,250 ppm. On d 35, three barrows and three gilts per treatment (one pig/block) were killed to provide carcass compositions. L-Carnitine had no effect (P > 0.10) on growth, percentages of carcass CP and lipid, or daily protein accretion. However, daily lipid accretion tended to decrease and then return to values similar to those for control pigs (quadratic P < 0.10) with increasing dietary L-carnitine. In Exp. 2, 96 crossbred pigs (initially 34.0 kg BW) were used to investigate the effect of increasing dietary L-carnitine in growing-finishing pigs. Pigs (48 barrows and 48 gilts) were blocked by weight and sex in a randomized complete block design (two pigs/pen and eight pens/treatment). Dietary L-carnitine replaced cornstarch in the control diet to provide 25, 50, 75, 100, and 125 ppm in grower (34 to 56.7 kg; 1.0% lysine) and finisher (56.7 to 103 kg; 0.80% lysine) diets. At 103 kg, one pig/pen was slaughtered, and standard carcass measurements were obtained. Dietary L-carnitine did not influence growth performance (P > 0.10). However, increasing dietary carnitine decreased average and tenth-rib back-fat (quadratic, P < 0.10 and 0.05), and increased percentage lean and daily CP accretion rate (quadratic, P < 0.05). Break point analysis projected the optimal dosage to be between 49 and 64 ppm of L-carnitine for these carcass traits. It is concluded that dietary carnitine fed during the nursery or growing-finishing phase had no effect on growth performance; however, feeding 49 to 64 ppm of L-carnitine during the growing-finishing phase increased CP accretion and decreased tenth-rib backfat.

Effects of dietary additions of modified tall oil, chromium nicotinate, and L-carnitine on growth performance, carcass characteristics, and bacon characteristics of growing-finishing pigs

“…These authors concluded that the inability of added fat to elicit a growth response was not altered by supplemented L-carnitine. Previous studies (Owen et al , 2001bSmith et al 1994) had observed reductions in backfat thickness and(or) increased percentage lean of pigs with additions of 50 to 125 ppm of added L-carnitine, contrary to our findings. Since initial carnitine status was not determined in the present study it is unknown if this contributed to the contrasting carcass results.…”

“…Delany et al (1999) observed an increase in serum insulin with 1% supplemented CLA. The lack of growth response to supplemental L-carnitine agrees with the earlier data of Owen et al (1994Owen et al ( , 2001b and Smith et al (1994). These authors concluded that the inability of added fat to elicit a growth response was not altered by supplemented L-carnitine.…”

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

“…This effect is due to an enhanced rate of β-oxidation of long-chain fatty acids. On the other hand, Owen et al (2001aOwen et al ( , 2001b failed to detect an effect of supplementing 50 or 125 ppm L-carnitine on growth performance of growing pigs. In other studies it was shown that pigs fed a diet supplemented with 50 ppm L-carnitine had a higher daily gain, better feed conversion, better carcass meatiness and thinner backfat (Rekiel and Zackiewicz 2004).…”

“…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.…”

“…In the studies on the effect of L-carnitine on the growth rate, feed conversion and the quality of pig carcasses, no clear results have been found (Owen et al 2001a, 2001b, Rekiel and Zackiewicz 2004, Han and Thacker 2006. L-carnitine has a role in the metabolism of lipids, carbohydrates and some amino acids and thus can modify the concentration of metabolites in blood (Grela et al 2005).…”