A Korean raw fish dish from olive flounder.

In recent years, the application of GroPro Aqua in aquatic products has attracted more and more attention including the interest of researchers. Recently, the latest research results on GroPro Aqua were included in the SCI journal 'Aquaculture' with an impact factor of 3.02 on April 6, 2020. This study tested the application of seven functional additives in low meal diet of olive flounder. GroPro Aqua is called yeast extract nucleotides (YEN) in this paper. The results showed that YEN (GroPro Aqua), GAB (gamma-aminobutyric acid) and SGS (song-gang stone) could be the most effective functional additives in the low fish meal diet of olive flounder.

Olive flounder is the most cultured fish in Korea, which has high economic value in the whole East Asia. As a cold, warm, benthic and carnivorous fish, the commercial diet of olive flounder usually includes 50-70% fish meal. In addition, there are higher requirements for protein demand and quality in feed for olive flounder. It has been reported that using plant protein instead of fish meal can reduce the growth and feed utilization of olive flounder. The purpose of this study was to evaluate the effects of seven additives in low fish meal diet on the growth and immune performance of olive flounder. In this study, the initial weight of olive flounder was 5.26 ± 0.17g, the dosage of fish meal in the control group (low fish meal group) was 45.5% (Table 1), and the dosage of GroPro Aqua was 4kg/T by replacing the same amount of flour.

Brief introduction of research results:

Improves production performance

Under the same feeding amount, GroPro Aqua can significantly improve the weight gain rate, specific growth rate, feed and protein efficiency of olive flounder. GroPro Aqua is YEN in Table 4.

Improve intestinal structure and function

GroPro Aqua is rich in nucleic acids, which can promote the growth and increase the length of intestinal microvilli, and increase the absorption surface area of nutrients. At the same time, GroPro Aqua can improve the trypsin activity and the ability of protein digestion and absorption. GroPro Aqua is E in Fig. 1 and is YEN in Table 8, Table 9.

Enhance immunity and disease resistance

The β-glucan and nucleic acid contained in GroPro Aqua can improve the non-specific immunity of fish and regulate the expression level of Hsp70.

In terms of non-specific immune related indexes, GroPro Aqua significantly improved the indexes of SOD enzyme, myeloperoxidase activity and neutrophil bactericidal function. GroPro Aqua is YEN in Table 7.

HSP-70 gene is related to stress resistance. When subjected to certain environmental stress, HSP-70 is induced to express, participate in stress protection, and improve the tolerance to environmental stress or injury. GroPro Aqua is YEN in Fig. 2.

GroPro Aqua improved the cumulative survival rate after challenged with Edwardsiella tarda, and enhanced the resistance to disease. GroPro Aqua is YEN in Fig. 3.