**8. Difficulties in broodstock standardization and acquisition of wild or genetic improved fish**

Standardizing a broodstock requires much more than just buying animals from different locations. To address this issue there is a need for a holistic knowledge of the whole process. The technical efficiency of a germplasm bank goes far beyond the knowledge of physicochemical characteristics of semen or a well-performed cryopreservation protocol. The first thing to be defined is the goal of germplasm bank: for restocking or fingerlings production to fish farming. When the goal is to restock environments, the most important aspect is the bank composition by animals that have the greatest possible genetic diversity. We should include here wild animals, even though they do not have a good seminal quality, but that make up the nearest setting of natural environment. On the other hand, when we set up a broodstock for commercial production of fingerlings we should seek animals with a greater genetic standardization, once the results will also have less variation. Thus, to establishment of a commercial broodstock we should analyze the genetic similarity degree of the animals before selecting them.

Insert wild fish in a broodstock whose objective is to produce fingerlings for fish farming can be a terrible mistake. Wild animals can carry parasites and therefore introduce them in the farm broodstock. Another important factor that should be considered is the broodstock domestication. According to Ruzzante [48], domestication is a process of adaptation of organisms in the man-made environment. We had an interesting experience a few years ago, when we use a semen bank from wild *P. mesopotamicus* to produce fingerlings from eighthgeneration captive females. The generated fingerlings were darker and presented a different behavior compared to those animals produced from domesticated parents. It is important to note that this was just an observation and not an experiment.

The formation of a germplasm bank should be conducted with the support of molecular techniques, which are still timidly used in Brazil [49]. Although being observed a high degree of genetic variability in broodstock of native species that have been formed in the country, their future efficiency may be compromised. We can cite as example the *C. macropomum* broodstock from two large farms in northern Brazil, where there was no problem of genetic variability, even with both having the same founder effect [50]. In another example, Jacometo et al. [51] reported that in addition to the high genetic variability in *C. macropomum* broodstock it was also observed a moderate differentiation and low genetic distance within themselves. The broodstock formation in this species occurred in 1972 [52].

The broodstock of *B. orbignyanus* [53] and *P. mesopotamicus* [54] used for restocking showed no genetic variability problems. We emphasize that even not having a compromising genetic variability degree it is important to consider the degree of genetic distance of the animals to be used as semen donors; once by accident the collection of semen from sibling animals can occur, which could be compromising depending on the ultimate goal of the germplasm bank.

This context serves to show how much we should be careful in setting up a germplasm bank from a random broodstock. It must be considered from the selected animals: the purpose of the genebank, age, genetic origin, and location; consanguinity degree, etc. A good application example of these concepts can be found in the article published by Streit et al. [55], in which two germplasm banks were created for use in breeding programs of two Brazilian fish species, *C. macropomum* and *Pseudoplatystoma reticulatum*.

**8. Difficulties in broodstock standardization and acquisition of wild or**

Standardizing a broodstock requires much more than just buying animals from different locations. To address this issue there is a need for a holistic knowledge of the whole process. The technical efficiency of a germplasm bank goes far beyond the knowledge of physicochemical characteristics of semen or a well-performed cryopreservation protocol. The first thing to be defined is the goal of germplasm bank: for restocking or fingerlings production to fish farming. When the goal is to restock environments, the most important aspect is the bank composition by animals that have the greatest possible genetic diversity. We should include here wild animals, even though they do not have a good seminal quality, but that make up the nearest setting of natural environment. On the other hand, when we set up a broodstock for commercial production of fingerlings we should seek animals with a greater genetic standardization, once the results will also have less variation. Thus, to establishment of a commercial broodstock we should analyze the genetic similarity degree of the animals before selecting

Insert wild fish in a broodstock whose objective is to produce fingerlings for fish farming can be a terrible mistake. Wild animals can carry parasites and therefore introduce them in the farm broodstock. Another important factor that should be considered is the broodstock domestication. According to Ruzzante [48], domestication is a process of adaptation of organisms in the man-made environment. We had an interesting experience a few years ago, when we use a semen bank from wild *P. mesopotamicus* to produce fingerlings from eighthgeneration captive females. The generated fingerlings were darker and presented a different behavior compared to those animals produced from domesticated parents. It is important to

The formation of a germplasm bank should be conducted with the support of molecular techniques, which are still timidly used in Brazil [49]. Although being observed a high degree of genetic variability in broodstock of native species that have been formed in the country, their future efficiency may be compromised. We can cite as example the *C. macropomum* broodstock from two large farms in northern Brazil, where there was no problem of genetic variability, even with both having the same founder effect [50]. In another example, Jacometo et al. [51] reported that in addition to the high genetic variability in *C. macropomum* broodstock it was also observed a moderate differentiation and low genetic distance within themselves. The

The broodstock of *B. orbignyanus* [53] and *P. mesopotamicus* [54] used for restocking showed no genetic variability problems. We emphasize that even not having a compromising genetic variability degree it is important to consider the degree of genetic distance of the animals to be used as semen donors; once by accident the collection of semen from sibling animals can occur, which could be compromising depending on the ultimate goal of the germplasm bank.

This context serves to show how much we should be careful in setting up a germplasm bank from a random broodstock. It must be considered from the selected animals: the purpose of

note that this was just an observation and not an experiment.

broodstock formation in this species occurred in 1972 [52].

**genetic improved fish**

64 Cryopreservation in Eukaryotes

them.
