Solid storage supplemented with serine of rooster semen enhances higher sperm quality and fertility potential during storage at 5?C for up to 120 h

Information on prolonging the storage duration of cold semen with acceptable fertility in roosters is limited. This study aimed to determine the efficiency of solid storage with the addition of various concentrations of serine to the Thai native rooster (Pradu Hang Dum) semen extender on semen quality and fertility potential during storage at 5 degrees C for up to 120 h. Pooled semen was diluted with a base extender and a gelatin extender con-taining 0, 2, 4, and 6 mM serine, then stored at 5 degrees C for 120 h. In Experiment 1, the semen quality and malondialde-hyde (MDA) concentrations were assessed at 0, 24, 72, and 120 h after storage. In Experiment 2, fertility potential in terms of fertility and hatchability rates was determined using the most effective solid-storage semen from Experi-ment 1. Sperm quality decreased with increasing storage time (P < 0.05). The lowest semen quality was observed in the control group since T24 of storage compared with the other groups (P < 0.05). Progressive motility, viability, and mitochondrial function were higher (P < 0.05) in the extender supplemented with gelatin and serine groups than those in the gelatin alone group at T72 and T120. In the extender supplemented with gelatin and serine groups, the highest semen quality was observed in the gelatin with 4 mM serine groups. The differences among extenders sup-plemented with serine were insignificant (P > 0.05), and the lowest MDA was observed in the gelatin with 4 mM serine groups. The fertility and hatchability rates in gela-tin with 4 mM serine at T24 were comparable to those in fresh semen (83.87 and 86.12% vs. 86.66 and 88.3%; P > 0.05). Those of T72 were significantly better than those of the control at the same hour of storage (64.08 and 71.61% vs. 52.38 and 64.48%), while those of T120 were not differ-ent among groups. In summary, a semen extender as a solid medium supplemented with 4 mM serine successfully preserved the rooster semen for a long duration up to 72 h of storage time.