The inclusion of algae Gracilaria domingensis in the diet of mullet juveniles (Mugil liza) improves the immune response

ABSTRACT

Five isonitrogenous and isolipidic diets were prepared with different inclusion levels of Gracilaria domingensis (GD; 0%, 5%, 10%, 15%, and 20%) with the objective to test its effects on growth and mullet immune system. The experimental diets were fed to juvenile mullet (Mugil liza, 0.42 ± 0.03g) for 60 days. The growth and expression of anti-CD3 and anti-CD4 primary antibodies for T lymphocytes were evaluated. Fish growth and feed conversion ratio decreased insignificantly by increasing GD levels up to 10% level, after which fish growth was significantly retarded. On the other hand, no significant difference was observed in granulocytes, lymphocytes, and monocytes values due to GD supplementation. Mullet fed with GD-enriched diets had a higher expression of anti-CD3 and anti-CD4 antibodies than those fed the control diet. It is concluded that a 5% inclusion level of G. domingensis in the diet increases immune competence without compromising fish growth.

KEYWORDS:

• Growth
• immune system
• lymphocyte
• macroalgae
• mullet
• Mugil liza

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the Conselho Nacional de Desenvolvimento Científico e Tecnológico (Bolsa de Produtividade, process number 404075/2016-9, process number 408921/2013-7) and Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (Ciências do Mar).