文摘
A 60-day feeding study was performed to evaluate the role of dietary commercial wood charcoal (CWC) in fish growth performance, body composition and water quality of fingerlings red tilapias (Oreochromis mossambicus × Oreochromis niloticus). Four levels of charcoal (10, 20, 30 and 40 g kg−1) were added to the control diet (0 g kg−1 CWC) and fed to red tilapias (initial weight of 1.20 ± 0.04 g). At the end of the feeding trial, the fish weight gain, specific growth rate, feed conversion ratio, protein efficiency ratio and energy retention of the fish groups fed 30 and 40 g kg−1 (CWC) in diet were significantly (P < 0.05) higher comparing with all other tested fish groups. Moreover, some proximate composition such as crude protein and nitrogen retention efficiency g kg−1 of the fish groups fed on 30 and 40 g kg−1 CWC diets showed higher values (P < 0.05) than those of other tested fish groups (0, 10 and 20 g kg−1 CWC). Apparent digestibility coefficients of protein and dry matter were improved (P < 0.05) in CWC-tested fish groups compared to the control fish group. These data were powered by the data of the water quality that showed significant (P < 0.05) enhancement in both dissolved oxygen and ammonia concentrations by the increment in dietary charcoal levels. The above-mentioned parameters' data suggested that 30 g kg−1 dietary CWC can be considered as a suitable level to maintain normal growth of red tilapia juveniles as well as to enhance water quality of the rearing area.
