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Moving beyond standards: how improving early life feeding strategies can boost finfish aquaculture Alessandro Moretti, INVE Aquaculture
Seabass and seabream farming are the cornerstone of Mediterranean aquaculture. Fry production of these two species has been steadily increasing over the past few decades and currently represents more than 90 percent of all fry produced in the Mediterranean. While this has been driven by well-established larviculture and weaning protocols, there is still room for improvement. Developing more efficient protocols that optimize the use of live food creates a window of opportunity that can enhance the quantity and quality of the produced fry while simultaneously reducing operational costs. Moreover, hatchery protocols can also be manipulated to positively modulate the robustness and growth response of future fish. As reported in the following sections, even the smallest breakthroughs in fish larviculture and nursery rearing protocols can excel performance at the farm gate, which is the ultimate goal of fry production.
Larval rearing protocols The use of specific products to balance the nutritional and microbiological profile of live feeds is paramount to safeguard a premium larval performance and maximize stress resistance. A scientific trial was performed with seabream larvae cultured using an optimized rearing protocol with newly developed enrichment for rotifers and Artemia, live feed conditioners, probiotics, and optimized dry feed protocol, and compared with conspecific larvae raised with standard commercial products. While similar survival was recorded at the end of weaning, the biomass achieved using the optimized
rearing protocol was significantly higher (Fig. 1). Survival after salinity stress tests was also notably higher when larvae were raised using the optimized rearing protocol (Fig. 1). It is also noteworthy that deformity levels were notably reduced in larvae reading using the optimized protocol: 2.3 percent, 1.0 percent, and 4.0 percent average operculum, tail, and severe deformities, respectively, were recorded in the optimized rearing protocol, which contrasts with the 9.3 percent, 6.5 percent, and 15.8 percent average deformities, respectively, observed in larvae reared in the control experimental treatment.
Figure 1. Survival (%) and biomass (g) at the end of weaning (left) and survival performance after the stress test (right) in seabream larvae raised using FRY 2.0 protocols and ingredients versus conspecifics raised with standard commercial products. The stress test was performed at 59 ppt for 33-day post-hatching (dph) larvae and at 69 ppt for 51-dph larvae.
Hatcheryfeed Vol 7 Issue 3 2019