Tris and Trehalose based modified cryopreservation dilutor in block freezing improves cryo-survivability and functionality of Sahiwal bull semen

Our study aimed to enhance cryoprotection and improve post-thaw sperm quality by using a new freezing protocolthat combines trehalose and glycerol.The semen ejaculate from each bull was collected and split into three aliquots.Split one was the control group (C), in which semen was extended in a tris fructose egg yolk glycerol (TFEG) extender and underwent the conventional freezing protocol.In split two (T1) and split three (T2) groups, the semen was diluted in tris fructose egg yolk extender containing 25% trehalose, with glycerol 5% in both groups. Split two (T1) underwent conventional freezing, whereas split three (T2) underwent aluminium block freezing.After freezing-thawing, the progressive sperm motility,viability, acrosome integrity, sperm velocity and path parameters were significantly ( p ≤ 0.05 ) improved in T2 among groups. Additionally, the degree of oxidative stress was substantially lower in T2 among groups.The present study's findings revealed the promising role of trehalose (25%) and glycerol (5%) in tris-based extender in achieving aluminium block freezing, as it significantly improved the post-thaw sperm survivability, and this method can suitably be used for quality frozen semen production.