Abstract

The present experiment aimed to analyse the advantages of diets containing 0.05%, 0.10% and 0.20% β-glucan on improving the non-specific immunity response, intestinal Vibrio, total aerobic bacteria, growth and ammonia resistance of pompano, Trachinotus ovatus (28.68 ± 0.23 g). After four weeks of diet feeding, the phagocytic index (PI), phagocytic ratio (PR), and serum lysozyme (SL) of pompano increased when adding β-glucan to their diet. The greatest immune response was observed in the pompano fed the feeds containing 0.05% and 0.10% of β-glucan (P≤0.041). Further, on day 28, the total intestinal bacteria were remarkably rose (P≤0.017) in the pompano those were fed 0.05%–0.10% of β-glucan. However, the Vibrio density and the proportion of Vibrio to the aerobic bacteria were considerably higher in pompano fed the basal (P≤0.045). Also, the pompano that offered dietary β-glucan grew faster than the pompano in control. On days 14 and 28, the β-glucan concentration and fish immune response (PR, PI, SL) correlated positively (r≥ 0.379, P≤0.012). Moreover, on day 28, the total intestinal bacteria showed a profound correlation with the β-glucan level (r=0.312, P=0.012). However, the Vibrio to total bacteria ratio increased as the Vibrio count was corresponded negatively to the β-glucan quantity (r= −0.528, P≤ 0.001). On day 28, the β-glucan addition was highly correlated to the phagocytic index (PI) and intestinal Vibrio. The predicted optimum levels of β-glucan to maximise responses of pompano were 0.121% and 0.122% of β-glucan for PI and intestinal Vibrio, respectively. Moreover, under stress ammonia, the pompano that was given β-glucan diets gained better survival rates and lower relative risks than pompano fed the base diet. In conclusion, the 0.05% to 0.10% β-glucan diet could boost the immune activity, improve intestinal microbes, enhance the tolerance capacity to the ammonia of the cultured pompano, T.ovatus.

Full Text
Published version (Free)

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call