Quality of semen frozen in medium containing glycerol with different levels: A study of Palu fat-tailed sheep raised in the tropics

Abstract

Abstract Palu Fat-Tailed Sheep (Palu-FTS) is a native animal of Palu with high adaptability to tropical environment, but its population is limited. Therefore, this study aims to determine the semen quality of Palu-FTS, which was frozen using different glycerol levels in a basic medium containing Ringer lactate, egg yolk tris citrate, fructose, and antibiotics. The activities were carried out in two stages, the first stage was to find the best medium for diluting semen using different egg concentrations. Meanwhile, in the second stage, the best medium was used as a diluent to freeze the samples along with successive addition of different glycerol concentrations, namely K1 3%, K2 6%, and K3 9%. Statistical analysis showed that the addition of egg yolks to 9% diluent medium had a significant difference compared to the other treatments of 3% and 6%. The mean percentage analysis of Palu-FTS spermatozoa motility before freezing also revealed that there was a significant difference (P<0.05) between the control and the treatment groups, which indicates that adding 3%, 6%, and 9% egg yolks maintained the sperm motility. However, no difference was observed (P>0.05) between P1, P2, and P3 treatments, but P3 had the highest value of 83b± 0,236 compared to P2 and P1 with 82±0,562 and 79±0,416, respectively. The viability percentage analysis of sperm before the freezing showed that there was a significant difference (P<0.05) between control and treatment P1, P2, and P3, but no difference was observed (P>0.05) between the 3 treatments of 84±0,514, 85±0,234, and 87±0,354, respectively. Statistical analysis of the sperm’s viability percentage also showed that there was a significant difference (P<0.05) between the treatments, but no difference (P>0.05) between P2 and P3. Meanwhile, P2 had the highest motility rate, which indicates that the right concentration of glycerol was used as a cryoprotectant. Based on the results, the addition of glycerol as a cryoprotectant protected spermatozoa during the freezing process, consequently, the supply of superior Palu-FTS was maintained in the tropics.