Effect of Different Levels of the Dietary Psidium guajava L. Leaves Meal and Extract on Growth Performance, Feed Utilization, Body Composition, Immune-Related Genes Expression, and Health Status of the Thinlip Grey Mullet (Liza ramada) Fish

Seven isonitrogenous (25.12% crude protein) were formulated to evaluate the effects of using different levels (0, 1, 2, and 4%) of guava (Psidium guajava L.) leaves meal (GLM) and their extracts (GLE) at the same levels as dietary supplements on growth performance, feed utilization, body composition, health status, and immune-related genes expression in the thinlip grey mullet (Liza ramada) fish. The results showed significant differences in growth performance; where, fish fed on 4% GLE recorded the highest values in final body weight (FBW), average daily weight gain (ADG), specific growth rate (SGR), feed conversion ratio (FCR), and protein efficiency ratio (PER), except for protein productive value (PPV), which recorded the highest value on 2% GLE. However, significant differences were noticed in energy utilization. Significant differences were noticed in body composition data between all treatments. The crude protein content in fish was decreased in all treatments compared to the control group. The differences between all biochemical parameters of serum were significant. The highest values of urea, creatinine, ALT, and AST were recorded in the control group when compared with all treatment groups. In terms of total protein, albumin, and globulin, the lowest values were recorded in the control group. Significant differences were observed in both amylase and lipase activities, with all treatments showing higher levels compared to the control group. In terms of both interleukin-1β and hepcidin genes expression, they were significantly decreased by about 99.9 in all treated groups (1, 2, and 4%) compared to the control group (0%). In conclusion, the treatments of fed guava leave meal and their extracts in Liza ramada have positive effect to improve the health status of the fish compared to the control.