Functional feed additives improve feed utilization in low fishmeal diets

South Korean researchers tested seven different functional additives in a low fishmeal diet in olive flounder and found that yeast extract nucleotides, gamma-aminobutyric acid and son-sang stone could have beneficial effects on growth and feed utilization performance.

April 9, 2020

South Korean researchers tested seven different functional additives in a low fishmeal diet in olive flounder (Paralichthys olivaceus). Encapsulated sodium butyrate (ESB), gamma-aminobutyric acid (GAB), selenium-yeast (SeY), yeast extract nucleotides (YEN), yucca meal (YUM), song-gang stone (SGS) and protease (PRT) were evaluated in an eight-week feeding trial. Eight experimental diets were fed to 5.26 ± 0.17 g (mean ± SD) juvenile olive flounder in triplicates. A low-FM basal diet without feed additives was considered as control (CON); seven other diets were prepared by adding 4 g ESB, 158 mg GAB, 2 g SeY, 4 g YEN, 1.5 g YUM, 4 g SGS, and 175 mg PRT per kg of basal diet.

Weight gain, specific growth rate, feed efficiency and protein efficiency ratios of fish fed diets with yeast extract nucleotides, gamma-aminobutyric acid, and song-sang stone were significantly higher than fish fed on the control diet. Superoxide dismutase activity of fish fed YEN and myeloperoxidase (MPO) and nitroblue tetrazolium (NBT) of fish fed YEN, GAB, SGS, ESB, and YUM were significantly higher than those of fish fed CON diet

Whereas, there were no significant differences in non-specific immune responses among fish fed YEN, GAB, SGS, ESB, and YUM and diets. Heat shock protein 70 gene expression of fish fed YEN and SeY was significantly higher than fish fed the control diet.

Intestinal villi length of fish fed YEN, GAB, SGS, and ESB was significantly higher than those fed CON. Also, intestinal trypsin activity of fish fed YEN, GAB, SGS, ESB, and PRT was significantly higher than those fed CON diet.

After seven days of challenge tests, fish fed diets YEN, GAB, SGS, PRT, and YUM had higher cumulative survival than those fed on the control diet.

Researchers conclude that yeast extract nucleotides, gamma-aminobutyric acid and son-sang stone could have beneficial effects on growth and feed utilization performance, MPO and NBT activity, intestinal villi length, intestinal trypsin activity, and cumulative survival of olive flounder fed low-fishmeal diets.

Check out the study here.