Sperm cryopreservation reduces offspring growth

Abstract

Sperm cryopreservation is routinely used in reproductive medicine, livestock production and wildlife management. Its effect on offspring performance is often assumed to be negligible, but this still remains to be confirmed in well-controlled within-subject experiments. We use a vertebrate model that allows us to experimentally separate parental and environmental effects to test whether sperm cryopreservation influences offspring phenotype under stress and non-stress conditions, and whether such effects are male-specific. Wild brown trout ( Salmo trutta ) were stripped for their gametes, and a portion of each male's milt was cryopreserved. Then, 960 eggs were simultaneously fertilized with either non-cryopreserved or frozen-thawed semen and raised singly in the presence or absence of a pathogen. We found no significant effects of cryopreservation on fertilization rates, and no effects on growth, survival nor pathogen resistance during the embryo stage. However, fertilization by cryopreserved sperm led to significantly reduced larval growth after hatching. Males varied in genetic quality as determined from offspring performance, but effects of cryopreservation on larval growth were not male-specific. We conclude that cryopreservation causes a reduction in offspring growth that is easily overlooked because it only manifests itself at later developmental stages, when many other factors affect growth and survival too.

Conservation Biology and Reproduction in a Time of Developmental Plasticity

“…To some extent, these results with amphibian spermatozoa mirror those found by Nusbaumer and colleagues [ 102 ] in an experiment in which semen from wild-caught brown trout ( Salmo trutta ) was frozen using a method [ 103 ] that produced fertilization rates comparable to those of non-cryopreserved spermatozoa. Cryopreservation did not reduce fertilization rates or affect embryo viability, but did reduce larval growth by about 4%.…”

“…In their 2014 study, Nusbaumer et al [ 102 ] included an interesting extra treatment in their experiment to evaluate the morphology of juvenile brown trout obtained using cryopreserved spermatozoa. Individual embryos derived from the cryopreserved spermatozoa were either exposed to a pathogenic bacterial suspension ( Aeromonas salmonicida ), or only sham exposed as a control treatment.…”

Paternal-effect genes revealed through semen cryopreservation inPerca fluviatilis

“…It has been demonstrated in rainbow trout that sperm cryopreservation did not affect fertilization rates 28 , and no effects on development and survival during the embryo stage. However, fertilization of eggs using cryopreserved sperm led to significantly reduced larval growth after hatching 24 . This is in contrast to our study, where after using cryopreserved semen for fertilization of eggs it resulted in increased WBW of the larvae compared to larvae obtained with fresh semen at the end of our experiment.…”

Evolutionary consequences of environmental effects on gamete performance

“…For example, it is well known that cryopreservation causes both lethal and sublethal damage to sperm (including DNA fragmentation, oxidative stress and reduced mitochondrial function) with functional consequences for sperm and offspring [114]. A recent study in the brown trout Salmo trutta showed that the processes involved in cryopreservation have negative effects on offspring growth even after just one generation [115]. Cryopreservation may also induce epigenetic changes in sperm, with early indications suggesting that patterns of DNA methylation and histone modification are impacted and may be transmitted over several generations [116].…”