Submitted to: Journal of Reproduction and Fertility
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 30, 1995
Publication Date: N/A
Interpretive Summary: Almost all commercial turkeys are produced using artificial insemination. When semen is inseminated fresh or within six hours of collection, fertility of eggs is high. However, when sperm is stored at refrigeration temperatures for 24 hours or longer, a progressive decline in fertility over the course of egg production is observed. This limits the efficiency of artificial insemination programs. The objective of this study was to determine if the decline in fertility after 24 hour storage is a result of fewer sperm surviving selection and storage in the hen's sperm storage tubules. Hens were inseminated weekly with either fresh semen or semen stored 24 hours and eggs were evaluated using a bioassay which determined the number of sperm embedded in the outer layer of the egg. The number of sperm in the outer layer of the eggs was approximately eighty percent higher for hens inseminated with fresh versus stored semen throughout the study. These findings document that sperm stored in the refrigerator for 24 hours before insemination have a reduced ability to be stored in the hens reproductive tract. These results will benefit scientists studying ways to improve semen preservation procedures to increase the efficiency of artificial insemination in turkeys.
Technical Abstract: A progressive decline in fertility over the course of egg production may be observed when turkey hens are inseminated weekly with semen stored 24 h. The objective of this study was to determine if this decline is a result of fewer sperm surviving in vivo selection and storage in the hen's sperm storage tubules (SST). Hens were inseminated weekly over the first 11 wk of egg production with either fresh semen or semen stored 24 h. A total o 301 eggs was evaluated by determining the density distribution of sperm embedded in the outer perivitelline layer (PL). For the 11 weeks of egg production, fertility of hens inseminated with fresh semen was >94%. Conversely, the percent fertility of eggs from hens inseminated with stored semen in weeks 1-3 was > 94% but thereafter averaged 86%. The mean number of sperm in the PL was higher (P< .001) by week when hens were inseminated with fresh (17.4ñ0.7 sperm/5.5 mm2 ) versus stored semen (3.5ñ1.7 sperm/5.5 5mm2) throughout the study and over all weeks combined (P<.001). It is concluded that as a result of storage for 24 h, fewer sperm are stored in the SST and consequently, fewer sperm are present at the site of fertilization, thus contributing to the depressed fertility.