Dietary immunostimulants reduced infectivity of Diplostomum spp. eye fluke in common carp, Cyprinus carpio L

Juvenile common carp Cyprinus carpio L. (5.52 +/- 1.66 cm, TL) were fed on four diets containing either betaglucan (MacroGard, 1 g kg -1), nucleotides (Optimun, 0.2 g kg - 1), chitosan (deacetylated chitin >= 75% shrimp shells, 10 g kg -1) or a basal control diet for 35 days to test whether these so-called immunostimulants could affect eye fluke Diplostomum spp. infection success. The immunostimulants diets reduced the number of eye fluke infecting the eyes of C. carpio, with significantly higher infections in the control diet (4.78 +/- 1.27) compared with the chitosan (2.08 +/- 0.87), nucleotide (2.98 +/- 1.01), and beta-glucan (1.41 +/- 0.79) diets. To our knowledge, this is the first study to provide evidence that beta-glucan, nucleotides, and chitosan diets can aid against a Diplostomum infection and provides valuable preliminary knowledge on the use of immunostimulants to ameliorate parasitic infections.

Automated summary

This study demonstrates the effectiveness of beta-glucan, nucleotides, and chitosan in combating Diplostomum infection in juvenile common carp, providing valuable insight into the use of immunostimulants to alleviate parasitic infections.