Effects of Ortho-Phosphate on Growth Performance, Welfare and Product Quality of Juvenile African Catfish (Clarias gariepinus)

Fishes

Michael Oster¹  Sebastian M. Strauch²  Berit Wasenitz²  Harry W. Palm²  Judith Bahr²  Adrian A. Bischoff²  Björn Baßmann² 

[1] Leibniz Institute for Farm Animal Biology (FBN), Wilhelm-Stahl-Allee 2, 18196 Dummerstorf, Germany;Professorship Aquaculture and Sea-Ranching, Faculty of Agricultural and Environmental Sciences, University of Rostock, Justus-von-Liebig-Weg 6, 18059 Rostock, Germany;

关键词: African catfish (Clarias gariepinus);    growth;    feed efficiency;    elevated phosphate concentrations;    welfare;   

DOI  :  10.3390/fishes4010003

来源: DOAJ

【 摘 要 】

Ortho-phosphate inside recirculation aquaculture systems is limited as a consequence of precipitation and regular water exchange rates. To improve plant growth in coupled aquaponics, phosphate fertilizer addition to hydroponics can increase PO₄³⁻-P concentrations inside the process water. We investigated the effects of four PO₄³⁻-P concentrations (<10 (P0), 40, 80, 120 mg L⁻¹) in rearing water on growth performance, feed efficiency, and welfare traits of juvenile African catfish (Clarias gariepinus Burchell, 1822). By trend, optimum specific growth rate of 2.66% d⁻¹ and feed conversion ratio of 0.71 were observed at 40 and 80 mg L⁻¹ PO₄³⁻-P. Higher PO₄³⁻-P significantly affected skin coloration, swimming activity and external injuries, with the palest and inactive fish combined with most external injuries in the P120 group. Mineral and protein contents in the fish remained unaffected, while fat content inside the fillets enriched with increasing PO₄³⁻-P. Inorganic P in blood plasma increased significantly, while phosphate concentrations inside the fillet remained unchanged. We suggest that PO₄³⁻-P concentrations of 40 to 80 mg L⁻¹ do not reduce the performance of African catfish aquaculture, while increased values of 120 mg L⁻¹ affect fish welfare. This allows limited addition of PO₄³⁻-P fertilizer in coupled aquaponics with African catfish to support plant growth.

【 授权许可】

Unknown