Dietary Brown Propolis Extract Modulated Nonspecific Immune System and Intestinal Morphology of Pacu Piaractus mesopotamicus

The immunomodulatory and growth promoter effects of brown propolis ethanolic extract (PEE) were determined in pacu. Fish (28.4 +/- 0.4 g) were randomly distributed into 12 polyethylene circular tanks (250 L, 30 fish per tank) and fed for 60 days with a commercial diet (32% crude protein) supplemented with 0.0, 1.5, 3.0 and 4.5% (v/w) of PEE in a totally randomized experimental design (n=3). Fish organic defense cells numbers such as thrombocytes and neutrophils increased (p<0.05) in fish fed 3.0% dietary PEE. Serum lysozyme concentration also increased (p<0.05) in fish fed 1.5 and 3.0% PEE supplementation when compared to unsupplemented fish. Growth parameters were not influenced (p>0.05) by treatments. Moreover, dietary PEE decreased (p<0.05) fish intestinal muscular thickness when compared to control treatment. Intestine villi height also significantly decreased in fish fed 3.0% PEE. Long term dietary PEE at 3.0% supplementation level modulated fish nonspecific immune system and it is a non-toxic substance for pacu.

Automated summary

The study demonstrated that brown propolis ethanolic extract can modulate the immune system, increase white blood cell counts, and enhance lysozyme concentration in pacu fish. Additionally, it had minimal impact on growth parameters but reduced intestinal muscular thickness and villi height.