Growth Performance, Feed Utilisation, Digestive and Metabolic Enzyme Activity, and Liver Morphohistology in Hybrid Tilapia (Oreochromis mossambicus × Oreochromis niloticus) Juveniles Fed with the Inclusion of Chitosan in Their Diet
Yuniel Méndez‐Martínez, Alan Rodrigo Vera-Veliz, Edilmar Cortés‐Jacinto, Yanis Cruz‐Quintana, Aroldo Botello-León, Pedro Daniel Mendoza-Carranza, Natalia S. Calvo
Abstract
This study aimed to evaluate the growth performance, feed utilisation, digestive and metabolic enzyme activity, and liver histology in juveniles of hybrid red tilapia (Oreochromis mossambicus × Oreochromis niloticus) fed with the inclusion of chitosan in their diet. Six dietary chitosan levels (0 “control’’, 10, 20, 30, 40, and 50 g kg−1) were used to feed juvenile fish (initial weight 7.50 ± 0.20 g) that were cultured for eight weeks in 18 tanks at a density of 15 fish/tank. The growth performance presented significant differences (p ˂ 0.05) for weight gain, specific growth rate, feed conversion ratio, hepatosomatic index, and survival rate. The digestive and metabolic enzyme activities were significantly (p < 0.05) influenced by the levels of chitosan in the administered diet. Histologically, no damage was found in the liver; however, morphometrically, a significant difference (p < 0.05) was found in the hepatocyte area and sinusoid area. Vacuolisation of hepatocytes was found in treatments with 40 and 50 g kg−1 of chitosan in the diet. Treatments with doses of chitosan showed a better response (p < 0.05) compared to the control treatment in most of the different groups of variables analysed. The result of the principal component analysis suggests that a diet containing 40 g kg−1 of chitosan is optimal for tilapia growth performance.