Effect of long term dietar y supplementatio n of Lippia citriodora extract on semen quality traits in brown hare (Lepus europaeus)

There is an internationally growing interest concerning application of natural extract sources in animal production area in order to improve the husbandry welfare and the performance. The aim of the present study was to evaluate the effect of dietary supplementation with a natural extract of Lippia citriodora, containing verbascoside as main component, on some quality traits of semen of hare, monitoring also the welfare status of animals. Hares were randomly divided into four groups of 3 animals each, homogeneous by age and body weight, and fed ad libitum and free access to water until the end of the trial. Animals were fed for 240 days a commercial diet assigned to four dietary treatments: control diet (CON) and the diet supplemented with 1 g.kg-1 of natural extract (low natural extract – LNE) or 1.5 g kg-1 of natural extract (medium natural extract – MNE) or 2 g.kg-1 of natural extract (high natural extract – HNE). All hares were subjected to the following experimental measurements: weekly relief of feed intake, body weight and blood samples at 0 and at 240 day of trial, and semen collection at 180, 210 and 240 days of trial. The body weight of the hares and their feed intake were not affected by the experimental treatment. At the end of the trial, sperm volume, pH and sperm concentration values were not effected by Lippia citriodora extract treatment, and the mean values recorded were 0.543 ml, 7.4 and 263.25 106 per ejaculate, respectively. The dietary treatment negatively affected (P < 0.05) the sperm motility values in LNE, MNE and HNE groups. In conclusion, the results of the present work underline a possible negative effect of the Lippia citriodora extract on the semen quality characteristics, besides the improvement in welfare status of the treated hares, reflected in a better lipid profile and an improved plasma oxidative markers.