ANTI-AGEING EFFECTS OF DIETARY BEE PRODUCTS AND CALORIE RESTRICTION ON SEMEN PRODUCTION AND OXIDATIVE DAMAGE IN OLDER BROILER BREEDER MALES

This study was conducted to investigate the effects of calorie restriction and dietary bee products (apilarnil plus royal jelly) supplementation on reproductive and oxidative responses and to determine the possibilities that these treatments may be used in retarding the reproductive ageing of broiler breeder males. At 52 weeks of age, broiler breeder males were assigned to four treatment groups. The control group was fed on restricted feed as recommended by the breeder company throughout the study; the ad libitum group was fed ad libitum for a four-week period; the bee products group was fed similar to the control group except that their diet was supplemented with apilarnil and royal jelly for a four-week period and in the last group calorie restriction (45 % of standard diet) was applied for a four-week period. After a four-week adaptation period, the experiment was continued for 18 weeks. The results obtained in the present study have demonstrated that the percentage of dead sperm was the most affected semen characteristic by reproductive ageing. Long-term moderate feed restriction could not prevent age-related declines in sperm production. Dietary bee products supplementation or calorie restriction for a fourweek period positively affected the semen characteristics, and these beneficial effects could be maintained to some extend up until 72 weeks of age. Calorie restriction enhanced antioxidant defence for the first four-week period; however, this beneficial effect could not be sustained until the end of the experiment.Key words: broiler breeder males; ageing; semen characteristics; oxidative stress; bee products; calorie restrictionVPLIV ČEBELJIH PRIDELKOV IN OMEJEVANJA KALORIJ NA PROIZVODNJO SEMENA IN OKSIDATIVNI STRES PRI STAREJŠIH SAMCIH PLEMENSKIH BROJLERJEVAbstrakt: Študija je bila izvedena z namenom raziskovanja učinkov omejevanja kalorij in dodajanja prehranskih čebeljih pridelkov (apilarnil in matični mleček) na reprodukcijske in oksidativne odzive ter ugotoviti možnosti uporabe prehranskih dodatkov za zaviranje reproduktivnega staranja samcev plemenskih brojlerjev. Pri starosti 52 tednov so bili samci plemenskih brojlerjev razporejeni v štiri skupine. Kontrolna skupina je bila ves čas študije krmljena z restrikcijsko krmo po priporočilih podjetja, ki se ukvarja z gojenjem plemenskih broilerjev; skupina ad libitum je bila štiri tedne hranjena ad libitum; skupina, pri kateri so bili dodani čebelji pridelki je bila krmljena podobno kot kontrolna skupina, le da je bila njihova prehrana štiri tedne dopolnjevana z apilarnilom in matičnim mlečkom, zadnja skupina pa je štiri tedne dobivala kalorično omejeno hrano (45 % običajne prehrane). Po štiritedenskem prilagoditvenem obdobju se je poskus nadaljeval še 18 tednov. Rezultati, pridobljeni v tej študiji, so pokazali, da je bila najbolj prizadeta značilnost staranja povišan odstotek mrtvih semenčic v ejakulatu. Dolgoročna zmerna omejitev krme ni preprečila starostnega zmanjšanja proizvodnje smenčic. Dodatek prehranskih čebeljih pridelkov ali omejevanje kalorij v obdobju štirih tednov je pozitivno vplival na značilnosti semena. Ti blagodejni učinki so se ohranili vse do starosti do 72 tednov. Omejitev kalorij je okrepila tudi antioksidativno obrambo v prvih štirih tednih raziskave; vendar pa se je ta ugodni učinek kasneje izgubil.Ključne besede:samci plemenskih brojlerjev; staranje; značilnosti semena; oksidativni stres; čebelji proizvodi; omejitev kalorij