Semen Cryopreservation for Ex Situ Management of Genetic Diversity in Chicken: Creation of the French Avian Cryobank

Abstract

The need for semen preservation in domestic birds is a result of the reduction in genetic variability of domestic bird livestock and of the increasing risk of line extinction for health and safety reasons. Cryopreservation of embryos and primordial germ cells (PGC) is not routinely feasible in birds. The project therefore involved semen frozen in optimal safety and traceable conditions. Whole blood samples were also frozen to provide samples of analyses of genomes and health status. The feasibility of using ex situ conservation, i.e., collecting biological material to be stored outside the usual production area of the species (ex situ genetic stock), to preserve and manage rare breeds was tested with 4 subfertile populations: 3 rare experimental lines used for research into energy metabolism (R+), growth (Y33), and immunity (B4/B4), reared under known health status and the oldest endangered patrimonial French breed, the Gauloise dorée with an unknown health status. A general infrastructure was set up for the health screening and remediation of diseases, collection and storage of frozen cells and 2 sites were created for the storage of frozen samples. The screening and remediation of diseases of the Gauloise dorée, which was contaminated with various Salmonella and Mycoplasma strains, was achieved by successive treatment of parents, incubated eggs and young chicks with Baytril followed by Tiamulin. For each line, 474 to 994 semen straws have been frozen, thawed, and the semen evaluated. Insemination of frozen-thawed semen into females of the same genetic origin or of an egg-type commercial breed produced chicks in every case. For the most subfertile lines, insemination with egg-type females significantly increased the reproductive success. In conclusion, we report on the benefits of a semen and blood cryobanking complex for the management of endangered lines and strains of domestic birds. Current stocks made possible the restoration of more than 96% of the initial genome. This project also provided technical solutions to resolve some of the health problems frequently encountered for gene preservation in poultry.

A century of poultry genetics

“…Such an inventory will participate in a general approach to document genetic resources in poultry, but also aims at stimulating collaborations regarding the conservation and characterisation of rare or extreme genotypes. Some efforts of cryobanking have been undertaken but require further investment by public institutions (Blesbois et al, 2007).…”

Specific features of in vivo and in vitro sperm storage in birds

“…It is also of major interest for the preservation of endangered breeds as it greatly facilitates the development of international programmes to assess genetic biodiversity. Recent advances in cryopreservation technology for poultry semen have resulted in the emergence of cryobanking, which is now being developed in an increasing number of countries (see Blackburn, 2006;Woelders et al, 2006;Blesbois, 2007;Blesbois et al, 2007).…”

Processos de incubação artificial associados à aplicação de diferentes métodos reprodutivos em matrizes semipesadas

“…Além destes, vários são os fatores ambientais que atuam sobre a fisiologia reprodutiva das aves, tais como temperatura, clima, disponibilidade de alimento e interações sociais (LESKA & DUSZA, 2007). Inserida neste contexto, a biotecnologia é uma da ferramenta importante no processo reprodutivo das aves, visando o desenvolvimento de técnicas ligadas principalmente à inseminação artificial e à criopreservação de sêmen (RUTZ et al, 2007), sendo que a conservação da variabilidade genética em espécies de animais domésticos é um desafio para a produção sustentável de recursos alimentares para os humanos e para o manejo animal (BLESBOIS et al, 2007) As aves submetidas à inseminação artificial não apresentaram diferença significa (P>0,05) na taxa de fertilidade em relação às aves submetidas à monta natural e nem entre os fatores analisados e na interação entre estes. A proposta primordial da inseminação artificial aplicada a aves preza que todas as aves recebam o sêmen, enquanto as aves submetidas à monta natural nem sempre possuem a comprovação que todas realizaram a cópula.…”