Growth performance, digestion and metabolism to fish meal replacement by rice protein concentrate in Chinese soft-shelled turtle Pelodiscus sinensis

An 8-week feeding trial was conducted to evaluate growth performance, whole-body composition, metabolism and digestion of Chinese soft-shelled turtle Pelodiscus sinensis fed with fish meal replacement by rice protein concentrate and squid paste supplementation diets. Three isonitrogenous and isoenergetic practical diets were formulated with the inclusion of 60% fishmeal (CT), 42% fish meal +18% rice protein concentrate (RP) and 42% fish meal +18% rice protein concentrate +1% squid paste (feeding attractant) (RPS), respectively. Microcapsule lysine was supplemented in RP and RPS diets to balance the amino acid profile. Turtles (initial weight 30.65 g) were fed thrice (6:00, 12:00 and 18:00) daily to apparent satiation. The results showed that growth performance in RP group showed no significant difference with that in CT group (P > .05). In addition, daily squid paste supplementation significantly improved growth performance, nutrients retention and relative feed intake (P < .05). Significantly increased activities of hepatic alanine aminotransferase as well as intestinal protease, γ-glutamyl transpeptidase, aminopeptidase N and carboxypeptidase A were also observed in RPS group (P < .05). The results suggested that rice protein concentrate could replace 18% dietary fish meal in Pelodiscus sinensis with microcapsule lysine supplementation. Besides, diet with squid paste inclusion could improve feed intake and growth performance of Pelodiscus sinensis.