Accurately measuring the phenotype at the individual level is critical to the success of selective breeding programs. Feed efficiency is a key sustainability trait and is typically approached through feed conversion ratio (FCR). This requires measurements of body weight gain (BWG) and feed intake (FI), the latter being technically challenging in fish. We assessed two of the principal methods for measuring feed intake in fish over consecutive days: (1) group rearing 10 fish per group and video recording the meals and (2) rearing fish individually on a restricted ration. Juvenile Nile tilapia (Oreochromis niloticus) from the Genetically Improved Farmed Tilapia (GIFT) strain and the Cirad strain were entered into the study (128 GIFT and 109 Cirad). The GIFT strain were reared over three consecutive periods of 7 days each under different feeding, recording, and rearing scenarios (i) in groups fed an optimal ration (g100) or (ii) fed a 50% restricted ration (g50) both with video records of all meals and (iii) reared in isolation and fed a 50% restrictive ration. The Cirad strain were tested similarly but only for scenarios (i) and (iii). All fish were fed twice daily with a calculated ration. Correlations showed the same trends for the GIFT and the Cirad strains. For the GIFT strain, correlations were positive and significant for BWG and FI measured in scenarios (i) and (ii), 0.49 and 0.63, respectively, and FI measured in scenarios (i) and (iii) (0.50) but not for BWG measured in scenarios (i) and (iii) (0.29, NS). The phenotypic correlation estimated for FCR between scenarios (i) and (ii) with fish fed an optimal or a 50% restricted ration was low and not significant (0.22). Feed Conversion Ratio for GIFT fish reared in groups or in isolation and fed with a restricted ration [scenarios (ii) and (iii)] were not significantly correlated either. Social interactions between fish, potentially impacting their efficiency, may explain the results. Therefore, selective breeding programs seeking to improve feed efficiency will need to carefully plan the feeding rate and the rearing system used to estimate FCR in order to optimize selection for the targeted production system.

在个体水平上准确测量表型对于选择育种计划的成功至关重要。饲料效率是关键的可持续性特征，通常通过饲料转化率（FCR）实现。这需要测量体重增加（BWG）和饲料摄入量（FI），后者在鱼类中在技术上具有挑战性。我们评估了连续两天来测量鱼饲料摄入量的两种主要方法：（1）组每组饲养10条鱼并录制视频记录进餐，（2）以有限的比例单独饲养鱼。少年尼罗罗非鱼（尼罗罗非鱼）从遗传改良养殖罗非鱼（GIFT）菌株和Cirad菌株中选出（128 GIFT和109 Cirad）。GIFT菌株在不同的饲喂，记录和饲养方案下连续7天连续三个时段饲养（i）饲喂最佳配比（g100）的组或（ii）饲喂50％限制配比（g50）的两个视频所有膳食的记录，以及（iii）单独饲养并饲喂50％限制性饲料。对Cirad菌株进行了类似的测试，但仅适用于方案（i）和（iii）。每天给所有鱼饲喂两次，配给量定额。GIFT和Cirad菌株的相关性显示出相同的趋势。对于GIFT应变，在情景（i）和（ii）中测得的BWG和FI分别为0.49和0.63，并且在情景（i）和（iii）中测得的FI呈正相关且显着（0。50），但不适用于方案（i）和（iii）（0.29，NS）中测得的BWG。在情景（i）和（ii）中，饲喂最佳比例或限制比例为50％的鱼的FCR的表型相关性较低且不显着（0.22）。分组饲养或单独饲养并限制饲喂的GIFT鱼的饲料转化率[方案（ii）和（iii）]也没有显着相关性。鱼之间的社会互动可能会影响其效率，这可能解释了结果。因此，寻求提高饲料效率的选择性育种计划将需要仔细计划饲喂速率和用于估算FCR的饲养系统，以优化目标生产系统的选择。在情景（i）和（ii）中，饲喂最佳配比或限制配比为50％的鱼的FCR的表型相关性较低且不显着（0.22）。分组饲养或单独饲养并限制饲喂的GIFT鱼的饲料转化率[方案（ii）和（iii）]也没有显着相关性。鱼之间的社会互动可能会影响其效率，这可能解释了结果。因此，寻求提高饲料效率的选择性育种计划将需要仔细计划饲喂速率和用于估算FCR的饲养系统，以优化目标生产系统的选择。在情景（i）和（ii）中，饲喂最佳比例或限制比例为50％的鱼的FCR的表型相关性较低且不显着（0.22）。分组饲养或单独饲养并限制饲喂的GIFT鱼的饲料转化率[方案（ii）和（iii）]也没有显着相关性。鱼之间的社会互动可能会影响其效率，这可能解释了结果。因此，寻求提高饲料效率的选择性育种计划将需要仔细计划饲喂速率和用于估算FCR的饲养系统，以优化目标生产系统的选择。分组饲养或单独饲养并限制饲喂的GIFT鱼的饲料转化率[方案（ii）和（iii）]也没有显着相关性。鱼之间的社会互动可能会影响其效率，这可能解释了结果。因此，寻求提高饲料效率的选择性育种计划将需要仔细计划饲喂速率和用于估算FCR的饲养系统，以优化目标生产系统的选择。分组饲养或单独饲养并限制饲喂的GIFT鱼的饲料转化率[方案（ii）和（iii）]也没有显着相关性。鱼之间的社会互动可能会影响其效率，这可能解释了结果。因此，寻求提高饲料效率的选择性育种计划将需要仔细计划饲喂速率和用于估算FCR的饲养系统，以优化目标生产系统的选择。