Vandeputte Marc, Bugeon Jérôme, Bestin Anastasia, Desgranges Alexandre, Allamellou Jean-Michel, Tyran Anne-Sophie, Allal François, Dupont-Nivet Mathilde, Haffray Pierrick
GABI, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, France.
MARBEC, Université de Montpellier, Ifremer, CNRS, IRD, Palavas-les-Flots, France.
Front Genet. 2019 Dec 20;10:1225. doi: 10.3389/fgene.2019.01225. eCollection 2019.
Fillet yield, the proportion of edible fillet relative to body weight, is a major trait to improve in fish sold processed, as it has a direct impact on profitability and can simultaneously decrease the environmental impact of producing a given amount of fillet. However, it is difficult to improve by selective breeding, because it cannot be measured on live breeding candidates, its phenotypic variation is low, and, as a ratio, it is not normally distributed and a same change in fillet yield can be the result of different changes in fillet weight and body weight. Residual headless gutted carcass weight (rHGCW) is heritable and highly genetically correlated to Fillet% in rainbow trout, and can be predicted by the ratio of abdominal wall thickness to depth of the peritoneal cavity (E8/E23), measured on live fish by ultrasound tomography. We selected broodstock based on rHGCW, measured on sibs of the selection candidates, on ultrasound measurements (E8/E23) measured on the selection candidates, or a combination of both. Seven broodstock groups were selected: fish with 15% highest (rHGCW+) or lowest (rHGCW-) EBV for rHGCW, with 15% highest (E8/E23+) or lowest (E8/E23-) EBV for E8/E23, with both rHGCW+ and E8/E23+ (Both+) or rHGCW- and E8/E23- (Both-), or with close to zero EBVs for both traits (Mid). Seven corresponding groups of offspring were produced and reared communally. At harvest size (1.5 kg mean weight), 1,561 trout were slaughtered, measured for the traits of interest, and pedigreed with DNA fingerprinting. Offspring from groups Both+, rHGCW+ and E8/E23+ had a higher EBV for rHGCW than the control group, while down-selected groups had a lower EBV. Looking at the phenotypic mean for Fillet% (correlated response), up-selected fish had more fillet than down-selected fish. The highest difference was between Both+ (69.36%) and Both- (68.20%), a 1.16% units difference in fillet percentage. The change in Fillet% was explained by an opposite change in Viscera%, while Head% remained stable. Selection using sib information on rHGCW was on average more efficient than selection using the candidates' own E8/E23 phenotypes, and downward selection (decreasing Fillet%) was more efficient than upward selection.
鱼片产量，即可食用鱼片重量相对于鱼体重量的比例，是加工销售鱼类需要改进的一个主要性状，因为它直接影响盈利能力，同时还能降低生产一定量鱼片对环境的影响。然而，通过选择性育种来提高鱼片产量却很困难，原因在于无法对活体育种候选鱼进行测量，其表型变异较低，而且作为一个比例，它不呈正态分布，相同的鱼片产量变化可能是鱼片重量和鱼体重量不同变化的结果。无头去脏胴体剩余重量（rHGCW）具有遗传性，并且与虹鳟鱼的鱼片百分比高度遗传相关，可通过超声断层扫描在活鱼上测量的腹壁厚度与腹腔深度之比（E8/E23）来预测。我们根据rHGCW（在候选鱼的同胞上测量）、在候选鱼上测量的超声测量值（E8/E23）或两者的组合来选择亲鱼。选择了七个亲鱼组：rHGCW估计育种值（EBV）最高（rHGCW +）或最低（rHGCW -）的15%的鱼，E8/E23的EBV最高（E8/E23 +）或最低（E8/E23 -）的15%的鱼，rHGCW +和E8/E23 +（两者均 +）或rHGCW -和E8/E23 -（两者均 -），或两个性状的EBV都接近零的鱼（中间组）。产生了七组相应的后代并进行共同饲养。在收获规格（平均体重1.5千克）时，宰杀了1561条鳟鱼，测量了目标性状，并通过DNA指纹图谱确定了谱系。来自两者均 +、rHGCW +和E8/E23 +组的后代的rHGCW的EBV高于对照组，而经过向下选择的组的EBV较低。从鱼片百分比（相关反应）的表型平均值来看，经过向上选择的鱼的鱼片比经过向下选择的鱼更多。两者均 +（69.36%）和两者均 -（68.20%）之间的差异最大，鱼片百分比相差1.16个百分点。鱼片百分比的变化是由内脏百分比的相反变化所解释的，而鱼头百分比保持稳定。使用rHGCW的同胞信息进行选择平均比使用候选鱼自身的E8/E23表型进行选择更有效，并且向下选择（降低鱼片百分比）比向上选择更有效。
