Dietary inclusion of roselle improves body colouration and survival of the whiteleg shrimp (Litopenaeus vannamei) juveniles challenged against Vibrio harveyi

Abstract

This study was conducted to investigate the use of fresh and heat-treated roselle meals on growth, body colouration, and survival against Vibrio harveyi infection of whiteleg shrimp, Litopenaeus vannamei. Fresh (FR) or heat-treated roselle (HR) meals were added at 10% in isoproteic (38%) and isolipidic (7%) diets. A control diet was prepared without any addition of roselle meal. These diets were fed to shrimp (initial body weight 1.26g±0.02g) in triplicate groups for 8 weeks then challenged with V. harveyi. The growth, feed efficiency, total carotenoid content, and survival of shrimp and total Vibrio spp. counts in the hepatopancreas post-challenge test were estimated. No significant differences were recorded in the growth, survival, and feed utilization of the shrimp fed the roselle-added diets (FR or HR) compared to the control group. A significantly higher total carotenoid concentration was detected in shrimp fed with the FR and HR diets compared to the control (P<0.05). The challenge test with V. harveyi showed that the shrimp specimens fed with FR and HR diets gained higher survival and a lower total number of Vibrio spp. count in the hepatopancreas compared to the control group. The present finding suggests that fresh or heat-treated roselle meals provide a good source of carotenoid and increase the resistance of shrimp against vibriosis without affecting the growth and feed utilization.