Advances in avian semen cryopreservation

Semen cryopreservation in domestic birds has been studied extensively in the past fifty years. However, efficient methods to freeze semen of chicken of different breeds have emerged only in the last decade of the 20 century. Methods using cryoprotectants Glycerol, Dimethyl Acetamide and Dimethyl sulfoxide, slow or rapid freezing-thawing procedures, pellets or ampoules or straws packaging have been developed. Other methods have been studied in turkeys, guinea fowl, ducks, geese and some wild species. They are often less successful than chicken freezing methods with wide intra-species variability. Reliable predictors of suitability of semen for cryopreservation are also needed to improve freezing methods and to optimize the management of frozen semen. The quality of whole fresh semen measured by classical morphologic, metabolic and mobility tests is an indicator. More specialized tests such as membrane fluidity of fresh spermatozoa are indicative of the freezability of the gametes. The main use of semen cryopreservation in birds is the ex situ management of genetic resources in the context of decreasing in avian genetic biodiversity. This is achieved through germplasm cryobanks. There are three main national avian germplasm cryobank programs in 2006, operating in North America, The Netherlands and France respectively. They mainly include semen and blood samples issued from Public Research Lines, indigenous breeds and individual specific genotypes. The future need for semen cryopreservation programs will focus mainly on three objectives 1) improvement of predictors of suitability of males for semen freezing, 2) emergence of standardized methods of semen freezing in species other than chicken and 3) increasing development of avian cryobanks. __________________________________________________________________________________