Short-Term Storage of Semen of Rainbow Trout: Interactions of Time, Antibiotic, and Activator

Abstract

This study was designed to examine the main effects and interactions of time, presence of antibiotics, and type of sperm activators on the fertilization capacity (eyeing rate) of refrigerated semen of rainbow trout, Oncorhynchus mykiss. The semen samples were stored in the presence or absence of 250 IU ml⁻¹ penicillin and 250 μg ml⁻¹ streptomycin sulfate. Freshwater and a saline solution were used as sperm activators. The semen samples were stored at 2–3°C and fertilized after 0, 6, 8, 12, 19, and 25 days of storage. Fertilizing capacities of semen samples stored in the presence of antibiotics (63.8 ± 5.6%) were significantly (p < 0.05) higher than those stored in the absence of antibiotics (46.2 ± 6.7%). Also, the fertilizing capacities of stored semen samples activated using saline solution (70.7 ± 5.7%) had significantly (p < 0.05) higher values than those activated using freshwater (39.3 ± 5.9%). Semen samples stored in the absence of antibiotics completely lost fertilizing capacity within 19 days of storage. After 25 days of storage in the presence of antibiotics, induction of fertilization using freshwater and saline solution resulted in 0% and 79.8 ± 1.7% fertility, respectively.

Keywords:

• Oncorhynchus mykiss
• activator
• antibiotic
• semen
• storage

Acknowledgments

We would like to thank the manager (Mr. A. Pasha) and staff of KSRC for providing fish and practical help during stripping and incubation. Our appreciation is extended to Dr. A. Kheyrandish for English improvement to the text.