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Ho Chi Minh City, Vietnam

Dinh H.,Research Institute For Aquaculture No2 | Nguyen N.H.,University of The Sunshine Coast

Giant freshwater prawn (GFP) Macrobrachium rosenbergii is unique with males categorized in five different morphotypes (small claw, orange claw, blue claw, old blue claw and no claw males) and females in three reproductive statuses (mature ovary, berried and spawned females). In the present study we examined genetic inheritance of female and male morphotypes, their body weights and genetic associations between morphotypes and body traits. Restricted maximum likelihood fitting a multi-trait animal model was performed on a total of 21,459 body records collected over five generations in a GFP population selected for high growth rate. The estimates of variance components showed that there were substantial differences in additive genetic variance in body weight between male morphotypes. The low and significantly different from one genetic correlations between the expressions of body weight in male morphotypes also suggest that these traits should be treated as genetically different traits in selective breeding programs. By contrast, body weights of female types are essentially the same characters as indicated by the high genetic correlations between homologous trait expressions. In addition to body weight, male morphotypes and female reproductive statuses were treated as traits in themselves and were analysed as binary observations using animal and sire linear mixed models, and logit and probit threshold models. The estimates of heritability back-transformed from the liability scale were in good agreement with those obtained from linear mixed models, ranging from 0.02 to 0.43 for male morphotypes and 0.06 to 0.10 for female types. The genetic correlations among male morphoptypes were generally favourable. Body weight showed negative genetic associations with SM (-0.96), whereas those of body weight with other male morphotypes were positive (0.25 to 0.76). Our results showed that there is existence of heritable (additive genetic) component for male morphotypes, giving prospects for genetic selection to change population structure of GFP. © 2014 Dinh, Nguyen. Source

Nguyen Duy H.,Ghent University | Coman G.J.,CSIRO | Wille M.,Ghent University | Wouters R.,INVE Technologies N.V. | And 5 more authors.

The effect of water exchange, salinity regime, stocking density and diets on growth and survival of domesticated Penaeus monodon juveniles was evaluated in two independent experiments. In the first experiment, 1g-domesticated P. monodon juveniles were stocked at 10 animals per m 2 in 1-m 3 tanks to test two feeding regimes (mono diet of high protein pellets and a combination diet of high protein pellets and a fresh-food combination) and two rearing systems (a sand-based recirculation system with low water exchange; and a sand-based system with high rates of flow-through water). In the second experiment, performance of the animals was assessed when reared under 2 different water salinities and 2 stocking density treatments. Results of the two experiments indicated that the sand-based recirculation system with a water exchange at a rate of 5-10% a day and a combination diet of high protein pellets (55%) and a fresh-food combination consisting of 75% squid, 15% oyster and 10% blood cockle were suitable for the indoor rearing of the grow-out phase of P. monodon. Water salinity of 20-23g.L -1 and low stocking density of 10 animals per m 2 resulted in the best growth of the shrimp. Survival of P. monodon in the grow-out phase was significantly higher (P<0.05) at low salinity of 20-23g.L -1 as compared to high salinity of 32-33g.L -1 irrespective of stocking density. In conclusion, a sand-based recirculation system, high protein pellets and diversified fresh-food items, and water salinity of 20-23g.L -1 are suitable conditions for indoor grow-out phase up to 35g average of the black tiger shrimp P. monodon. © 2012 Elsevier B.V. Source

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