Jen-Hong Chu, Kuan-Ju Liu, Tsung-Meng Wu
This study was designed and implemented to investigate the effects of dietary supplementation of pitaya (Hylocereus polyrhizus) fermentation waste (PFW) on the growth performance and lipid peroxidation of Pinnate batfish, Platax pinnatus. A total of 150 fish (average 1.03 g) were randomly assigned to fifteen fibreglass tanks. Five isonitrogenous (40% crude protein), isolipidic (9% crude lipid) and isoenergetic (280 kcal/100 g) diets were formulated to contain 0 (PFW0), 3 (PFW3), 6 (PFW6), 9 (PFW9) and 18 (PFW18) grams PFW per100 g diet. After an 8-week feeding trial, the weight gain (WG) and specific growth rate (SGR) of fish fed the PFW9 diet were significantly higher (p < 0.05) than the fish fed other treatment diets. There was no significant difference in WG and SGR of fish fed the PFW3, PFW6 and PFW18 diets. The superoxide anion (O2−) production ratio and hepatic superoxide dismutase (SOD) activity of the fish fed the PFW9 diet were the highest (p < 0.05), whereas no significance differences in SOD activity were found among the fish fed PFW0, PFW3, PFW6 and PFW18. The value of thiobarbituric acid reactive substances (TBARS) of fish fed the PFW9 diet was significantly lower (p < 0.05) than those fed PFW0, PFW3 and PFW6 diets. The hepatosomatic index (HSI), liver glycogen and glucose-6-phosphate dehydrogenase activities were higher when PFW supplementation was increased.
The data generated by this study showed that the PFW9 supplementation resulted in the best growth performance and antioxidative status. Based on the second regression on the WG, the optimal PFW supplementation rate for Pinnate batfish was estimated to be 10.8 g/100 g.