August 2016
Experimental Pond
FISHBOOST Results: genetic background of winter survival in carp
First results on estimation of genetic parameters from WP2
Winter survival in common carp
Common carp is one of the most cultured freshwater fish species worldwide with production over 4,000,000 tons in 2014 of which European production was around 145,000 tons. It is one of the six fish species targeted within FISHBOOST. Common carp use energetic reserves (fat, glycogen, protein) during winter to maintain their body functions, and thus, these reserves are essential for winter survival.
Currently, there are up to 50% losses due to a suboptimal winter survival, with significant economic effects to producers. Understanding the genetic background of carp energetic reserves management and its effect on winter survival is essential for boosting of the carp sector because first wintering is a significant bottleneck for common carp production. Within FISHBOOST, we have been estimating genetic parameters of body reserves which might affect winter survival in one-year old common carp to assess the potential for selection responses. This is one of the goals of Work Package 2 (WP2) on production efficiency.
Boosting selective breeding in common carp
Until now, common carp in Europe has not been bred using systematic selection programmes and FISHBOOST aims to change this situation. To do that, data on genetic parameter estimates in different traits is essential. Amur mirror carp, a newly produced strain of carp from the Czech Republic, was used for the research experiments. This strain is suitable for crossbreeding with other carp breeds to produce commercial hybrids, because it has high performance in e.g. resistance to KHV.
However, no data are available for its suitability for a selection programme. The first results on estimating genetic parameters in one-year old common carp before and after wintering are now available (WP2). This information is expected to help us in understanding the genetic background of carp energetic reserves management and its effect on winter survival.
Until now, common carp in Europe has not been bred using systematic selection programmes and FISHBOOST aims to change this situation. To do that, data on genetic parameter estimates in different traits is essential. Amur mirror carp, a newly produced strain of carp from the Czech Republic, was used for the research experiments. This strain is suitable for crossbreeding with other carp breeds to produce commercial hybrids, because it has high performance in e.g. resistance to KHV.
However, no data are available for its suitability for a selection programme. The first results on estimating genetic parameters in one-year old common carp before and after wintering are now available (WP2). This information is expected to help us in understanding the genetic background of carp energetic reserves management and its effect on winter survival.
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Experimental design
The experimental stock was established by artificial spawning of broodstock fish of Amur mirror carp using a series of 4 factorial crosses between 5 females and 10 males. The experimental progeny was reared until semi intensive pond management conditions until autumn pond harvesting, when 1000 fish were individually weighed, measured and sacrificed for obtaining the important tissues (muscle, hepatopancreas and viscera) for further analysis. The rest of the fish were reared during the winter period. The same procedure was repeated with 1000 fish in the spring after the winter period. Progeny and their parents were genotyped for assignment to a single parental pair because that is necessary for the estimation of genetic parameters. First analyses were done for body weight (BW), body length (BL), Fulton’s condition coefficient (FC=BW/BL3), muscle fat content (MF), muscle dry matter (MDM), hepatosomatic index (HSI=100x(hepatopancreas weight/BW)) and visceral index (VSI=100x(viscera weight/BW)). |
 Weighing of Fish
Results
Before wintering, low to medium heritabilities (0.13 – 0.35) for the examined traits were observed (see Table below). In the spring period, the heritabilities for most traits were even higher (0.34 – 0.58). Moreover, heritabilities and correlations between traits had different patterns between autumn and spring. The genetic background of energetic reserve management seems to be quite complicated, for a deeper understanding of this complex process we need more data which FISHBOOST partners are collecting. However, preliminary results indicate that important production efficiency traits such as body weight (BW), muscle fat content (MF) and visceral fat (VSI) can be significantly changed in Amur mirror carp by selection. These results verified previous observations done on other carp breeds and under different conditions. So, we may draw a general conclusion that carp has a similar potential for boosting its performance as shown in salmon or rainbow trout when applying a systematic selection programme. The effectivity and applicability of a selection programme in carp culture and management conditions will be investigated. |
Table: Average values (mean±S.D.) and estimated heritabilities (h2±S.E.) for autumn (n= 924) and spring period (n= 932) of analysed traits in 1 year common carp
BW: body weight (g), BL: body length (mm), FC: Fulton’s condition factor, MF: muscle fat content (mg/g), MDM: muscle dry matter (%), HSI: hepatosomatic index (%), VSI: visceral index (%)
BW: body weight (g), BL: body length (mm), FC: Fulton’s condition factor, MF: muscle fat content (mg/g), MDM: muscle dry matter (%), HSI: hepatosomatic index (%), VSI: visceral index (%)
