Dellacqua Zachary, Di Biagio Claudia, Costa Corrado, Pousão-Ferreira Pedro, Ribeiro Laura, Barata Marisa, Gavaia Paulo J, Mattei Francesco, Fabris Andrea, Izquierdo Marisol, Boglione Clara
Department of Biology, University of Rome 'Tor Vergata', 00133 Rome, Italy.
Ecoaqua Institute, University of Las Palmas de Gran Canaria, 35214 Telde, Gran Canaria, Spain.
Animals (Basel). 2023 Feb 5;13(4):557. doi: 10.3390/ani13040557.
Gilthead seabream () production is a highly valued aquaculture industry in Europe. The presence of skeletal deformities in farmed gilthead seabream represents a major bottleneck for the industry leading to economic losses, negative impacts on the consumers' perception of aquaculture, and animal welfare issues for the fish. Although past work has primarily focused on the hatchery phase to reduce the incidence of skeletal anomalies, this work targets the successive pre-ongrowing phase in which more severe anomalies affecting the external shape often arise. This work aimed to test the effects of: (i) larger and smaller tank volumes, stocked at the same density; and (ii) higher and lower stocking densities maintained in the same water volume, on the skeleton of gilthead seabream fingerlings reared for 63 days at a pilot scale. Experimental rearing was conducted with gilthead seabream juveniles (6.7 ± 2.5 g), which were selected as 'non-deformed' based on external inspection, stocked at three different densities (Low Density (LD): 5 kg/m; Medium Density (MD): 10 kg/m; High Density (HD): 20 kg/m) in both 500 L and 1000 L tanks. Gilthead seabream were sampled for growth performance and radiographed to assess the skeletal elements at the beginning and end of the experimental trial. Results revealed that (i) LD fish were significantly longer than HD fish, although there were no differences in final weights, regardless of the water volume; (ii) an increase in the prevalence of seabream exhibiting cranial and vertebral axis anomalies was found to be associated with increased density. These results suggest that farmers can significantly reduce the presence of some cranial and axis anomalies affecting pre-ongrown gilthead seabream by reducing the stocking density.
金头鲷（）养殖是欧洲备受重视的水产养殖业。养殖的金头鲷出现骨骼畸形是该行业的一个主要瓶颈，会导致经济损失、对消费者对水产养殖的认知产生负面影响以及鱼类的动物福利问题。尽管过去的工作主要集中在孵化阶段以降低骨骼异常的发生率，但这项工作针对的是后续的育幼前期阶段，在此阶段经常会出现影响外形的更严重异常。这项工作旨在测试：（i）相同密度下较大和较小的养殖水箱体积；以及（ii）相同水量下较高和较低的放养密度，对在中试规模养殖约63天的金头鲷幼鱼骨骼的影响。实验养殖使用金头鲷幼鱼（约6.7±⒉5克），这些幼鱼经外部检查被选为“无畸形”，分别以三种不同密度（低密度（LD）：5千克/立方米；中密度（MD）：10千克/立方米；高密度（HD）：20千克/立方米）放养在500升和1000升的水箱中。在实验开始和结束时对金头鲷进行采样以评估生长性能，并进行X光摄影以评估骨骼元素。结果显示：（i）无论水量如何，低密度组的鱼比高密度组的鱼显著更长，尽管最终体重没有差异；（ii）发现出现颅骨和脊椎轴异常的金头鲷患病率增加与密度增加有关。这些结果表明，养殖户可以通过降低放养密度显著减少影响育幼前期金头鲷的一些颅骨和轴异常的出现。
