Kause Antti, Quinton Cheryl D, Ruohonen Kari, Koskela Juha
MTT Agrifood Research Finland, Biotechnology and Food Research, Biometrical Genetics, Jokioinen, Finland.
Br J Nutr. 2009 May;101(10):1444-51. doi: 10.1017/S0007114508091265. Epub 2008 Oct 1.
Animals may have target levels for lipid and protein stores which they try to maintain by feedback mechanisms. Thus, variation in initial body composition may be related to subsequent feed utilisation, for animals to maintain body composition in homeostasis. We assessed whether such relationships are genetically determined within a farmed population of European whitefish (Coregonus lavaretus) grown either on fishmeal or soyabean-meal diets. Soyabean meal is an increasingly-used ingredient in aquaculture feeds. Fish from thirty-five paternal families were analysed for initial body lipid and protein content, and for subsequent daily weight gain, daily feed intake, feed efficiency and their lipid and protein components. The results showed that none of the correlations of initial body lipid percentage with subsequent growth and feed utilisation were statistically significant. In contrast, low initial protein percentage was related to increased subsequent weight gain, protein gain and protein retention efficiency. This led to reversed ranking of families during growth for body protein percentage. Thus, mechanisms maintaining stable body lipid percentage across the population were weak, whereas the mechanisms stabilising body protein percentage were strong and successful. This explains the observations that cascades of lipid deposition occur during fish growth, leading to high amounts of phenotypic and genetic variation for percentage body lipid. In contrast, protein percentage remains phenotypically and genetically more invariable, reducing the potential for selective breeding. The soyabean-meal diet, in turn, induced only weak genotype x diet interactions, aiding in the genetic improvement of farmed fish to adapt to future feeds.
动物可能有脂质和蛋白质储备的目标水平，它们试图通过反馈机制来维持。因此，初始身体组成的差异可能与随后的饲料利用有关，以便动物将身体组成维持在稳态。我们评估了在以鱼粉或豆粕为食的养殖欧洲白鲑（Coregonus lavaretus）群体中，这种关系是否由基因决定。豆粕是水产养殖饲料中越来越常用的成分。对来自35个父系家族的鱼进行了初始身体脂质和蛋白质含量分析，以及随后的日增重、日采食量、饲料效率及其脂质和蛋白质成分分析。结果表明，初始身体脂质百分比与随后的生长和饲料利用之间的相关性均无统计学意义。相比之下，初始蛋白质百分比低与随后体重增加、蛋白质增加和蛋白质保留效率提高有关。这导致在生长过程中各家族身体蛋白质百分比的排名颠倒。因此，在整个群体中维持稳定身体脂质百分比的机制较弱，而稳定身体蛋白质百分比的机制则强大且成功。这就解释了在鱼类生长过程中会出现脂质沉积级联反应的现象，导致身体脂质百分比出现大量表型和遗传变异。相比之下，蛋白质百分比在表型和遗传上保持更稳定，降低了选择性育种的潜力。反过来，豆粕日粮仅诱导出较弱的基因型×日粮相互作用，有助于养殖鱼类的遗传改良以适应未来的饲料。
