Dietary glutamine supplementation on growth performance, intestinal morphology, hematic, enzymatic and immunological responses of Nile tilapia juveniles subjected to bacterial challenge

Author(s)

Pedro Luiz Pucci Figueiredo de Carvalho

• Document type: Doctoral Thesis
• Press: Botucatu. 2017-06-21.
• Institution: Universidade Estadual Paulista (Unesp). Faculdade de Medicina Veterinária e Zootecnia. Botucatu
• Defense date: 2017-05-26
• Advisor: Margarida Maria Barros; Wilson Massamitu Furuya

Abstract

Two experiments were conducted to evaluate the effect of glutamine (Gln) supplementation in Nile tilapia diets. Study I: aimed to determine the optimal level of Gln supplementation through productive performance responses, body composition, intestinal morphology and antioxidant capacity. Four hundred Nile tilapia juveniles (4.4 ± 0.1 g) were distributed in 40 aquaria (250 L each), in a recirculating water system. The experimental design utilized was completely randomized with five treatments (0, 0.5, 1.0, 1.5 and 2.0 % Gln) and eight replicates. The fish were hand fed four times a day for 90 days. Glutamine supplementation improved relative weight and length of intestine, as well as villus length and villus:crypt ratio, which could be related to the lower feed conversion ratio found on fish fed Gln-supplemented diets. Final body weight, weight gain and specific growth rate were also positively affected by Gln supplementation. Fish fed Gln diets showed increased gluthatione (GSH) concentrations in the intestine. Study II: the contribution of Gln supplementation in hematological, immunological and biochemical responses was assessed under bacterial challenge by Aeromonas hydrophila. After the feeding trial, 60 fish (244.5 ± 10.2 g) were inoculated intraperitoneally with the pathogen and transferred to the experimental challenge room. After 15 days, hematological, immunological and biochemical parameters were analyzed. The bacterial challenge affected the hematological and immunological parameters. However, Gln supplementation presented limited effect on these parameters, except for lysozyme concentration, which significantly increased on fish fed 1.5% Gln diets. In sum, dietary Gln supplementation promoted intestinal development and function, improved immune response and antioxidant system, as well as the growth performance. The dietary Gln supplementation level was estimated to be 1.40%. (AU)

• FAPESP's process: 14/01973-5 - Dietary supplementation of glutamine on growth performance, intestinal morphology, hematic, enzymatic and immunological responses of the Nile Tilapia subjected to bacterial challenge
• Grantee: Pedro Luiz Pucci Figueiredo de Carvalho
• Support Opportunities: Scholarships in Brazil - Doctorate