Short communication: Functional assessment of citral dietary supplementation on growth performance, intestinal parameters, and specific activity of the digestive enzymes of Sardinella brasiliensis reared in RAS

Abstract

Abstract This study evaluated the effects of dietary supplementation with citral on growth performance and intestinal parameters, and specific activity of the digestive enzymes of the Brazilian sardine Sardinella brasiliensis. The experiment was structured with two hundred and forty juvenile S. brasiliensis that were randomly distributed in a recirculating aquaculture system (RAS) composed of 12 circular tanks of 150 L (n = 20 per tank). A diet without citral addition (control) and three diets containing different levels of citral inclusion (0.5, 1.0 and 2.0 mL kg feed–1) were used in the fish feeding management during 20 days. After the period of dietary supplementation, the growth performance indexes of the fish were verified. Portions of the stomach and midgut were collected for analysis of digestive enzymes, as well as portions of the midgut for histological analysis. A significant positive relationship was found between citral supplementation and fish survival. In the specific activity of digestive enzymes, dietary citral supplementation at 2.0 mL kg feed–1 increased lipase and amylase activity. Citral supplementation positively influenced the number of villi and intestinal crypt depth. Furthermore, the inclusion of citral at 0.5 mL kg feed–1 increased the intestine diameter of the fish. However, the specific growth rate, weight gain and feed conversion were impaired with inclusions of citral at 0.5 and 1.0 mL kg feed–1. The results of the experiment suggest that the addition of citral as an additive in the diet of S. brasiliensis improved the survival of fish reared in RAS.