In neonatal pigs and gestating sows, as reviewed previously in this chapter, carnitine supplementation has in some experiments improved performance. However, in other cases, carnitine supplementation was without benefit. Perhaps as suggested by Galvez et al. (1996), carnitine supplementation should be considered under specific situations. Providing optimum nutrition for young or stressed animals, achieving maximum performance of animals with a high potential for productivity, and feeding diets that are high in fat and proportionally high in plant oils may be goals or conditions for which carnitine supplementation is warranted.
Only the physiologic L-carnitine should be used for fortification of diets. Gross et al. (1998) fed pigs and dogs diets containing supplemental carnitine and reported that plasma- free carnitine in both species increased at the same rate. Oral doses of 100 to 150 mg per kg (45.5 to 68.2 mg per lb) of body weight have been used as supplementation doses.
The National Research Council (NRC, 1998) currently does not include a specific recommendation for carnitine in swine diets.
