| In the present study, the feeding rate and growth rate of turbot at different temperature and growth performance at different low-temperature were conducted in family of 2012 and 2013 which were built of Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences. The effects of different temperatures to feeding rate and growth rate were analyzed. The genetic parameters of growth trait and the influence of different time to: heritability were analyzed in normal and low temperature. The specific results were as follows:1.700 normal and uniform size turbots of 160 dph of 10 families (70 individuals of each family) were selected in the feeding rate test.7 experimental groups with each group had 10 individuals from one same family were cultured in 8,9,10,10.5,11,11.5 and 12℃ condition separately. The results showed that there was no feeding behavior and keep stationary at the bottom under 8℃. At 12℃, all individuals were floating feed and energetic. The results showed that with the temperature rise, the feeding rate will accelerate.2. The 7 groups’turbots of 210 dph were cultured under conditions of 4,6,8,9,10,11, 12℃, and the experimental period lasted 40 days. The mortality was calculated at 4℃ and 6℃ while the growth rates were analyzed under 8,9,10,11,12℃. The results showed that the mortality is 10%at 4℃ and 2%at 6℃, which indicated that different low-temperatures had different effect to survival. The different growth rates were found at 8～12℃ and the growth rate were accelerated with the temperature increase. The results suggested that temperature was important ecological factor affect the growth of turbot.3. There were 536 individuals of 210 dph from 25 full- and half-sib families involved in this study. During the entire 90-day period of low-temperature(10.5～12℃), the individuals’ body weight (BW) and body length (BL) were measured consecutively every 18 days. The growth performance was described as SGR (specific growth rate). The SGRs of family ranged from 0.75±0.11 to 1.05±0.14 and the difference among families was significant(P<0.01). The results indicated that the families have different abilities of growth under the low-temperature. The SGR of individual ranged from 0.50 to 1.31 and the variation coefficient in each family is 0.06-0.16. This indicated that there was no significant difference in one family in growth rate.4. The objectives of this research were to assess the heritability of growth traits under low temperature conditions(10.5～12℃) in turbot (Scophthalmus maximus L.) and to analyze the correlation between body weight and body length. The design of the experiment was above. The heritability of BW and BL and the correlation between the two factors were estimated based on an individual animal model and the derivative-free restricted maximum likelihood (DFREML) method. These results showed that the heritability of BW and BL estimated under low-temperatures were 0.32±0.04 and 0.47±0.06 respectively. The BW had a medium heritability(0.2～0.4) and the BL had a high heritability(>0.45), which suggested that selection for increased weight and length was feasible. Moreover, there was potential for mass selection on growth. The genetic and phenotypic correlations between BW and BL were 0.95±0.01 and 0.91±0.01(P< 0.01) respectively, A significant correlation between BW and BL showed that indirect selection for BW could be effectively implemented in the selective breeding programs.5. The objectives of this present research were to assess the growth performance and heritability of growth traits within different duration under low-temperature(10.5～12℃) conditions in 536 turbots from 25 full-and half-sib families. During the entire 90-day period, the individuals’ body weight and body length were measured at 18/54/90 days separately. In the General Animal Model by the derivative-free restricted maximum likelihood (DFREML) method, the BW or BL of 18 days was as the covariate to estimate the heritability of BW and BL after 54 days and 90 days in low-temperature ambient and analyze the impact on growth of different time under low-temperature. These results showed that the (SGR) of 18-54 days and 55～90 days were 0.440±0.129,0.548±0.150(P < 0.01), respectively. The specific growth rate of turbot improved significantly with the time and the family growth performance were different from each other (the difference was significant(P<0.01) by the One-way ANOVA test) under the low-temperature. The results indicated that the turbot could adapt to low-temperature and the researcher could prolong the growth time under the low-temperature environment to cultivate the cold-resistance turbot. In addition, the heritability of BW at 54 days and 90 days were 0.440±0.129, 0.548±0.150(P<0.01) respectively; BL were 0.301±0.108,0.494±0.142(P<0.01) used the t-test), respectively. The heritability of BW and BL at 90 days was significantly higher than the heritability at 54 days. The additive genetic effect could weaken the impact of the common environmental effects with the time under low-temperature and improve the ability of inherited the fine character to filial generation.6.79 families include 33 full-sib families and 18 half-sib family groups were established in 2013.39 families (18 full-sib families and 8 half-sib family groups) with each family had 100 individuals of 220 dph were selected in the experiment in mid-August. The fishes were divided into two groups and one group was raised under normal temperature (15.0±0.5℃) while the other was raised under low temperature (9.0±0.5℃). The data of BL and BW were collected after the 60 days experiment. In the WOMBAT software, an individual animal model was used to estimate the heritability and correlation of BL and BW. The results showed that the heritability of BW and BL of normothermia*-group were 0.32±0.11,0.45±0.20, respectively. The former is a medium heritability(0.2-0.4) and the latter is a high heritability(>0.45). The heritability of BW and BL of hypothermia group were 0.26±0.12,0.38±0.18, respectively, both belongs to moderate heritability. The results showed that the breeding of turbot under normal temperature condition was superior to the low temperature environment. The BL were better than BW in breeding under normal or low temperature conditions. The genetic and phenotypic correlation of BW and BL of normothermia group were 0.94±0.05(P<0.05),0.87±0.01(P <0.01), respectively. The hypothermia group were 0.94±0.07(P< 0.05),0.88±0.01(P< 0.01), respectively. This showed the BW and BL were consistent in the turbot breeding at normal or low temperature conditions.In this study, the growth performance and heritability of turbot under low-temperature were obtained and guide to cultivate cold-resistant turbot. Researchers could select the rapid-growth family under low temperature conditions and extend the time of low-temperature to cultivate new varieties combining with hybridization. The new varieties could adapt to the low temperature in winter of culture areas in China and it will take great economic gains in the fish farmer. |
PDF Full Text Request