Effect of some Semen Extenders as a Natural Source of Antioxidants on Quality of Frozen Friesian Semen

Abstract

This study was designed to evaluate the possibility of using the optimal level of Moringa oleifera leaf aqueous extract (10, 15 or 20%) with 90, 85 or 80% saline (MOLE) as a semen extender of bull semen in comparing with three extenders, including Tris-egg yolk (TEY) without or with vitamin C at a level of 0.9 mg/ml (TEY+VC), and camel skim milk (CSM). Semen was collected from five Friesian bulls (350-450 kg LBW and 3-4 years old), twice a week for 5 weeks using artificial vagina. After ejaculation, mass motility was evaluated and only those of ≥70% were used in this study. Ejaculates were pooled, divided into 4 replicates and prepared for freezing. Semen was extended in TEY (control), TEY+VC, (CSM) and 15% MOE+85% saline (based on the best results of MOLE level). Semen was diluted, equilibrated at 5oC (4 h) and placed in liquid nitrogen (LN) at -196oC. Frozen semen stored for one month at least was warmed at 37oC for 30 sec. Semen evaluation for percentages of individual motility (IM), live sperm (LS), sperm abnormality (SA), acrosomal damage (AD) and hypo-osmotic swelling test (sperm cells with curled tail, CT) was estimated in diluted, equilibrated and thawed semen, while percentage of head to head agglutination (HHA) was determined in post-thawed semen only. Activity of AST, ALT, LDH and total antioxidant activity were determined in seminal plasma of post-thawed semen. Conception rate (CR) was recorded for Friesian cows inseminated with semen frozen with the four types of extenders. Results showed that percentages of IM, LS, SA, AD and CT in post-diluted and post-equilibrated semen, beside all previous characteristics and percentage of HHA in post-thawed semen showed the best results (P<0.05) in CSM, moderate in 15% MOE and TEY+VC, and the poorest in TEY. Enzyme activities of AST, ALT and LDH in post-thawed seminal plasma were the lowest (P<0.05) in CSM, followed by 15% MOE, while total antioxidants activity was higher (P<0.05) for TEY+VC, CSM and 15% MOE than for TEY, being the highest for 15% MOE. Artificial insemination of estrous synchronized cows with semen extended by different types of extenders indicated that conception rate of cows was significantly (P<0.05) the highest for Friesian cows inseminated with post-thawed semen extended with CSM (87.5%), moderate with both TEY+VC and 15% MOE (75%) and the lowest with TEY(62.5%). Extender containing 15% MOE showed the cheapest cost (4.80 L.E./100 ml) in comparing with CSM (6.45 L.E./100 ml), TEY+VC (13.95 L.E./100 ml), and even the conventional TEY extender (13.85 L.E./100 ml). In conclusion, extender containing 15% Moringa oleifera leaf extract and 85% saline solution could be successfully used, as a source of antibiotics and antioxidants, in extenders of frozen bull semen, being with the cheapest cost as compared to tris-egg yolk or camel skim milk extenders.