Effects of dietary supplementation of l-carnitine on the reproductive performance of sows in production stocks

Recent studies have shown that l-carnitine supplementation of sows during pregnancy and lactation increases their reproductive performance, but the optimum supplementation level has not yet been determined. In this study we investigated the effects of supplementation of 25 and 50 mg l-carnitine/kg on traits of reproductive performance of sows in production stocks. A trial with 2118 sows was conducted which were assigned to three groups, fed either control diets with low native l-carnitine concentrations or the same diets supplemented with 25 or 50 mg of l-carnitine/kg during pregnancy and lactation. Sows supplemented with 25 or 50 mg l-carnitine/kg diet had more piglets born alive than control sows (P < 0.05); piglets and litters of sows supplemented with 25 or 50 mg l-carnitine/kg were also heavier at birth and on day 21 than those of control sows (P < 0.05). Sows supplemented with 50 mg l-carnitine/kg diet and those supplemented with 25 mg l-carnitine/kg did not differ in the number of piglets born alive or piglet and litter weights at birth. On day 21, however, weights of piglets and litters were higher in sows supplemented with 50 mg l-carnitine/kg diet than in sows supplemented with 25 mg l-carnitine/kg diet (P < 0.05). In conclusion, this study shows that even a supplementation level of 25 mg l-carnitine/kg diet has beneficial effects on the reproductive performance of sows. Supplementation at 50 mg l-carnitine/kg diet is, however, superior with respect to weight development of litters during the suckling period.