Abstract
L-carnitine accelerates energy production in mitochondrial transport and oxidation of long-chain fatty acids. Pigs decrease sperm production activity in summer due to lower nutrition intake caused by lessened appetite in a high-temperature environment. A deterioration in semen is a serious problem especially in boars. It is presumed that L-carnitine supplementation may improve the characteristics of deteriorated semen. The present experiment compared the characteristics of semen obtained from boars in a non-treated control group and an L-carnitine supplemented experimental group, supplemented during the summer season. Semen collection was carried out twice in early and late September. Eight Duroc breed boars, 21 to 29 months old, were used. Commercial feed was given to the control group and feed supplemented with 50ppm L-carnitine to the experimental group. L-carnitine supplementation was conducted for two months from early August to late September ; semen volume, motile sperm, concentration of sperm, number of sperm, and abnormal sperm were determined at each semen collection. At the start of supplementation, motile sperm in control and experimental group were as 88.8±3% and 86.2±6%, respectively. In early September, while motile sperm was 52.5±13% in the control group, the experimental group showed a higher value (P<0.10), 86.7±3%, than that in the control group. In late September, no significant difference was found, but a tendency for higher values was maintained in the experimental group. The rate of abnormal sperm in the experimental group tended to be lower than that in the control group (P<0.10) in early September. While a significant difference was not found in other characteristics, the experimental group showed favorable sperm production values. These results suggest that the supplementation of L-carnitine maintained the normal characteristics of semen due to an increase in the reduced activity of the entire body in high-temperature environment.
