Effect of partial or total replacement of fish meal with Procambarus clarkii by-product meal in Oreochromis niloticus diets

The present study aimed to evaluate the effect of partial or total replacement of fish meal (FM) with Procambarus clarkii by-product meal (PBM) on O. niloticus growth performance, feed utilization and health. Five isonitrogenous (30% protein) experimental diets were formulated and applied to O. niloticus with initial body weight 10.94 g for four months in ceramic ponds. The control group contained 0% of PBM, while D2, D3, D4 and D5 contained 25, 50, 75 and 100% replacement of FM with PBM, respectively. The present study revealed that the protein content of PBM was 33.13% and its amino acids profile fulfilled the requirements of O. niloticus. All analyzed heavy metals of PBM, except arsenic and iron, were in the permissible limits for O. niloticus. Moreover, the growth performance and feed utilization parameters of fish of all treated groups were significantly different than those of the control one, but the best results were recorded in fish fed diets D2 and D3, followed by fish fed diets D3 and D4. Moreover, the histological investigation revealed that the liver showed alterations only in fish fed diet D5, and the kidneys showed alterations in fish fed diets D4 and D5, however, the gills showed alterations in all treated groups.