| Rainbow trout (Onchorynchus mykiss) is one of the most important economicfish introduced in our country，and is enjoyed by the majority of consumersbecause of its characteristics of delicious and nutritious meat. In addition, rainbowtrout is suitable for artificial intensive farming and the area for aquatic breedinghas expanded each year. However, due to the diversity of rainbow trouthybridization forms and the indistinction of the genetic background of parents, it isdifficult to obtain superior strains of genetic stability, and thus cannot meet theneeds of large scale production. Therefore, cultivating of fine strains of rainbowtrout with growing fast, large individual, strong resistance and good meat is aninevitable requirement for the sustainable development of rainbow trout farming.while, using statistical analysis method to identify the different families is also akind of auxiliary method of breeding. This article mainly uses of joint allometryscaling model to compare the differences between different strains of rainbowtrout, and is designed to provide a quick and easy method of parental identificationand selection. Genetic models for jointly analyzing multiple allometries areconstructed as well to provide a theoretical basis for allometric genetic parameterestimation and guiding to synchronously improve morphological traits and bodyweights in Rainbow trout and other aquatic animals.1、At four-years old, body weight and20morphological traits were observedin148individuals collected from5rainbow trout strains. A joint static allometrymodel was used to simultaneously estimate allometry scalings of multiple body shapes to body weight, longitudinal sizes to body length, vertical sizes to bodyheight and transversal sizes to body width. Multiple comparisons of partialallometry scalings at the same trait between different rainbow trait strains wereconducted with Newman-Keuls test after the best joint static allometry scalingmodel was established by stepwise regression analysis. The results showed thateach strain of rainbow trout performed significantly different partial allometryscalings. Multiple morphological traits to body weight, total length or body heighthad the maximum value of allometry scaling. Non-significant allometricassociations were found between head length and body weight, head width andbody weight, eyes interal and body weight, mouth length and body weight, caudalpeduncle length and body weight, anal fin depth and body weight as well as analfin base length and body weight among five strains for rainbow trout. In addition,all strains showed significant allometry scalings for dorsal snout distance to bodylength and caudal peduncle depth to body depth. By comparing the allometryscalings among different strains for rainbow trouts and analyze theirmorphological variation characteristics, an effective theoretical method wasproposed to identify morphological feature of strains for rainbow trout and otheraquatic animal.2、Random regression models are adopt to genetically analysis allometryscalings of morphological traits to body weights in Rainbow trout, Oncorhynchusmykiss. In this study, experimental groups including the first generation of hybrid（F1）and the second generation of hybrid group（F2）.By using stepwise regression analysis, phenotypic joint static/ontogenetic allometry scaling model isoptimized to choose the significant partial allometry scalings of multiple partialbody sizes to entire body size. The two random regression models are constructedto genetically analyze multiple static/ontogenetic allometries. One embeds the bestjoint static allometry model into fixed and additive genetic effects of simpleanimal model. Another considers not only the fixed and additive genetic effects onbest joint ontogenetic allometry model but also the time-dependence of permanentenvironmental effects in the repeated records animal model. Genetic parameterestimation of multiple allometries can be implemented with restricted maximumlikelihood for random regression model. Results indicate that body length has thelargest significant allometric associations with body weight, the order in geneticvariances for allometry scalings is likely consistent with that in phenotypic partialallmetry exponents. The largest genetic correlation for allometry scalings is-0.8675between body width and dorsal fin base length, followed by-0.6194between body length and body depth, and the minimum one is-0.0217. Additivegenetic variance for ontogenetic allometry of body length to weight is estimated as0.2929. |
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