SEMEN QUALITY, TESTOSTERONE LEVEL, SOME ENZYMES ACTIVITIES AND FERTILITY OF MALE APRI RABBITS TREATED WITH DIFFERENT LEVELS OF OLIVE LEAF EXTRACT

The present study was designed to investigate the efficacy of different dietary levels of ethanolic olive leaf extract (OLE), as a source of natural antioxidants, on quality and production of semen, some enzymes activities and testosterone concentration in blood serum and some seminal plasma characteristics of APRI rabbit bucks. A total of 24 mature rabbit bucks of APRI line (3-3.4 kg live body weight and 9-12 months of age) were divided into four similar groups, 6 bucks in each. Bucks in the 1^st group were fed a reference diet (17.75% CP and 2500 DE Kcal/Kg diet) without any supplements (G1, control). While, those in the 2^nd (G2), 3^rd (G3) and 4^th (G4) treatment groups were fed the same diet supplemented with olive leaf extract at levels of 0.5, 1 and 1.5 ml/kg diet, respectively. Bucks were fed ad libitum on the experimental diets for a period of 17 wk (8 wk as a treatment period and 9 wk as main semen collection period. Semen was evaluated physically, chemically and by transmission electron microscope (TEM). Results showed that all levels of dietary OLE supplementation increased (P<0.05) total semen volume in G2, G3 and G4 as compared to G1, being the highest in G4. Sperm characteristics, including percentages of progressive motility, livability, abnormality and cell concentration of spermatozoa improved (P<0.05) in G3 and G4 as compared to G2 and G1. Examination of sperm cells in all groups by TEM cleared enhancing the abnormalities in cell membrane and acrosome, axoneme as well as chromatin of spermatozoa in G4 as compared to other groups. Bucks in G4 showed the lowest (P<0.05) peroxidase and fructose testes in seminal plasma as compared to other groups. Activity of LDH in seminal plasma was higher (P<0.05) in all treatment groups than in control one, being the highest in G4 and the lowest in G1.  Activity of AST and ALT and testosterone concentration in blood serum were not affected by OLE treatment. Activity of ALP in G4 and LDH activity in G3 and G4 increased (P<0.05) as compared to other groups. Kindling rate and reproductive index were improved (P<0.05) in rabbit does mated by bucks of G3 and G4 as compared to that of G2 and G1, being the highest in G4) 81.67 ، %6.5 .( In conclusion, supplementation of the diet with olive leaf extract, in particular at a level of 1.5 ml/kg, as a natural antioxidants source, is essential for improving reproductive performance and consequently semen quality and fertility of breeding rabbit bucks (natural or artificial mating) without adversely effects on healthy status.