QTL’S
Genetic marker assisted selection is the current “state of the art” technology in rainbow trout breeding. The technique is based on identifying well-defined genome sequences (Quality Trait Loci / QTL’s) in the proximity of the actual gene coding for specific traits. Whenever the particular trait is desired in the offspring, parent fish are selected based on positive findings of the QTL. Since parent fish can be either homozygotic or heterogenic / QTL positive on both or just one chromosome allele, and the QTL requirement can be related to one or both parent fish, intensity of selection differ accordingly. AquaSearch has adapted genetic marker assisted selection in our general breeding programmes and the genetic propagation of most current breeding lines. Hence several important traits are in the process of being fixed in future generations. Please see datasheets on individual breeding lines for details.
In addition to this, AquaSearch is offering to use genetic marker assisted selection in commercial batches. Individual customers might have identified benefits or requirements related to specific traits with an adjacent QTL available, and customized batches can be produced on request. Primarily male contribution is offered, but occasionally also female contribution can be included. Seasonal variation in availability should be anticipated and well advance planning is advised, with a minimum 6-week advance ordering necessary.
Genetic background and breeding lines available with QTL’s
QTL’s available depend on the specific breeding line. Please refer to individual product data sheets and individual QTL’s for linkage.
Also please note that a QTL’s has not been, and will never be, identified for every important trait. Some traits are to complex and controlled by an array of genes, not easily correlated to single genome sequences. These include growth, feed conversion and other key features, and will have to be selected for by traditional optimum contribution breeding (family breeding) or the more comprehensive multi loci genomic selection technology.
QTL RTFS
Genetic background and breeding lines available with RTFS QTL’s
One of the diseases where resistance has been linked to well defined loci is the universally important rainbow trout fry syndrome (RTFS). At least eight different loci on three different chromosomes have been linked to natural resistance against RTFS, making this trait an obvious candidate for marker assisted selection.
AquaSearch has access to the technology necessary for detecting these QTL’s, and selection of parent broodstock for each new generation of brood stock fish is supported by identifying these. Eventually a high degree of natural resistance against RTFS will be integrated in all AquaSearch breeding lines.
Meanwhile, AquaSearch is offering a shortcut to immediate improved natural resistance to RTFS. By identifying neo-males carrying the relevant QTL’s and using these males when fertilizing commercial batches, AquaSearch can offer our customers a unique supplement in the control of a serious fish disease.
The feature is available with most AquaSearch breeding lines, but seasonal variation in availability should be anticipated and well advance planning is advised, with a minimum 6-week advance ordering necessary. Please see datasheets on individual breeding lines for details.
QTL RTFS availability depend on seasonal variations and the specific breeding line. Please refer to individual product data sheets.
QTL RTFS general reproduction application (breeding lines)
- AquaSearch FRESH
- AquaSearch LATE
- AquaSearch CROSS
- AquaSearch CROSS+
QTL RTFS optional add on feature (breeding lines)
- AquaSearch FRESH
- AquaSearch LATE
- AquaSearch CROSS
- AquaSearch CROSS+
QTL Vibrio
Genetic background and breeding lines available with Vibrio QTL’s
One of the diseases where resistance has been linked to well defined loci is however classical vibriosis caused by Vibrio anguillarum. This disease is almost exclusively affecting production in saltwater and less relevant to trout production in freshwater. Although efficient vaccines does exist, protection is not always 100 % and combining various prophylactic and management measure including improved natural resistance does often make sense.
University of Copenhagen together with AquaSearch has identified a QTL highly correlated to improved natural resistance to Vibrio anguillarum. This QTL is now an integrated part of AquaSearch breeding effort in selected breeding lines and offered on request as an add on feature in commercial egg batches.
The later representing a shortcut to immediate improved natural resistance to vibriosisi. By identifying neo-males carrying the relevant QTL’s and using these males when fertilizing commercial batches.
The feature is available with selected AquaSearch breeding lines only and seasonal variation in availability should be anticipated with well advance planning advised. Please see datasheets on individual breeding lines for details.
Genetic background and breeding lines available with RTFS QTL’s
QTL Vibrio availability depend on seasonal variations and the specific breeding line. Please refer to individual product data sheets.
QTL Vibrio general reproduction application (breeding lines)
- AquaSearch CROSS
- AquaSearch CROSS+
QTL Vibrio optional add on feature (breeding lines)
- AquaSearch LATE
- AquaSearch CROSS
- AquaSearch CROSS+
QTL ICH
Genetic background and breeding lines available with ICH QTL’s
One of the diseases where resistance has been linked to two well defined loci, is the universally important parasite Ichthyophthirius multifiliis (white spot disease or ICH). University of Copenhagen in cooperation with AquaSearch has identified two highly significant QTL (on chromosome 16 and 17) correlated with lower infestation level (fewer parasites / fish). Making this trait an obvious candidate for marker assisted selection.
AquaSearch has access to the technology necessary for detecting these QTL’s, and pending the breeding line selection of parent broodstock for each new generation of brood stock fish is supported by identifying these. Eventually a high degree of natural resistance against ICH will be integrated in relevant AquaSearch breeding lines.
Meanwhile, AquaSearch is offering a shortcut to immediate improved natural resistance to ICH. By identifying neo-males carrying the relevant QTL’s. By using these males when fertilizing commercial batches, AquaSearch can offer our customers a unique supplement in the control of a serious fish disease.
The feature is available with most AquaSearch breeding lines, but seasonal variation in availability should be anticipated and well advance planning is advised, with a minimum 6-week advance ordering necessary. Please see datasheets on individual breeding lines for details.
Genetic background and breeding lines available with ICH QTL’s
QTL ICH availability depend on seasonal variations and the specific breeding line. Please refer to individual product data sheets.
QTL ICH general reproduction application (breeding lines)
- AquaSearch FRESH
- AquaSearch LATE
- AquaSearch CROSS
QTL RTFS optional add on feature (breeding lines)
- AquaSearch FRESH
- AquaSearch LATE
- AquaSearch CROSS
- AquaSearch CROSS+
QTL LATE
Genetic background and breeding lines available with LATE QTL’s
One key trait which has been challenging rainbow trout farmers at all times, is age of maturation. For obvious reasons, manipulating this trait by traditional breeding is a time-consuming process. Breeding work related to most AquaSearch breeding lines have had focus on age of maturation (reduced risk of second winter maturing females) since before AquaSearch were founded, and some of our breeding lines are unique in this context, with significantly lower risk of second winter maturation, then any other genetics in the market. To further improve on this trait and decrease the risk on second winter maturation to an absolute minimum, associated QTL’s has been identified and patented.
These highly significant genetic markers allow AquaSearch to breed intensively towards reduced risk of second winter maturation in breeding lines where this trait is a feature, and it allows large trout producers to request the use of males carrying the QTL’s for the production of commercial batches.
In either case trout farmers will be allowed to produce large well pigmented rainbow trout in both fresh and saltwater despite a suboptimal temperature profile where the risk of second winter maturation is better reduced to a minimum, and significant seasonal fluctuations in temperature and oxygen saturation is disqualifying the use of triploid fish.
Breeding lines available with LATE QTL’s
QTL LATE availability depend on seasonal variations and the specific breeding line. Also please refer to individual product data sheets.
QTL LATE general reproduction application (breeding lines)
- AquaSearch LATE
- AquaSearch CROSS
QTL LATE optional add on feature (breeding lines)
- AquaSearch LATE
- AquaSearch CROSS
- AquaSearch CROSS+