Tomato Pomace with Exogenous Enzymes and/or Amino Acids Enhanced Growth Performance, Histological Parameters and Gene Expression for Growth in Nile tilapia Fish (Oreochromis nilotius)

Abstract

This study evaluated the impact of feeding tomato pomace with or without enzymes and amino acids to Nile tilapia for 8 weeks on growth performance, digestive enzymes, histological parameters and some liver gene expression. Five experimental diets were formulated with similar protein content (28%): (1) a control diet without tomato pomace (TP), (2) TP 15%, (3) TP 15% with lysine (1.79%) and methionine (0.94%), (4) TP 15% with gallizyme (0.2%) and (5) TP 15% with lysine, methionine and gallizyme. The results revealed significant improvements in growth performance, especially body gain by 31.05% and 33.03% and FCR by 21.83% and 23.35% in the 4th and 5th groups, respectively, as compared to the 2nd group. Enzymes alone or enzymes with amino acids significantly increased Villi length and goblet cells number in the intestine of tilapia. There was no significant difference in the activities of lipase and amylase and levels of total protein, albumin and globulin in all groups. The relative expression levels of IGF-1 and GH in the liver of tilapia were significantly increased (p<0.05) in the last three groups. Finally, addition of enzymes with or without amino acids to the Nile tilapia diets improved the growth performance parameters and gene expression.