Safety evaluation of four faba bean extracts used as dietary supplements in grass carp culture based on hematological indices, hepatopancreatic function and nutritional condition

Lingling Ma; Gen Kaneko; Jun Xie; Guangjun Wang; Zhifei Li; Jingjing Tian; Kai Zhang; Yun Xia; Wangbao Gong; Haihang Li; Ermeng Yu

doi:10.7717/peerj.9516

Safety evaluation of four faba bean extracts used as dietary supplements in grass carp culture based on hematological indices, hepatopancreatic function and nutritional condition

PeerJ. 2020 Jul 7:8:e9516. doi: 10.7717/peerj.9516. eCollection 2020.

Authors

Lingling Ma^#^{1

2}, Gen Kaneko^#³, Jun Xie¹, Guangjun Wang¹, Zhifei Li¹, Jingjing Tian¹, Kai Zhang¹, Yun Xia¹, Wangbao Gong¹, Haihang Li⁴, Ermeng Yu¹

Affiliations

¹ Key Laboratory of Tropical & Subtropical Fishery Resource Application & Cultivation, Pearl River Fisheries Research Institute of CAFS, Guangzhou, China.
² National Demonstration Center for Experimental Fisheries Science Education, Shanghai Ocean University, Shanghai, China.
³ School of Arts & Sciences, University of Houston-Victoria, Victoria, TX, USA.
⁴ Guangdong Provincial Key Lab for Plant Development, School of Life Sciences, South China Normal University, Guangzhou, China.

^# Contributed equally.

Abstract

Faba bean (Vicia faba, FB) is known to improve the texture of fish meat but retards growth possibly by inducing hemolysis, hepatopancreas damage, and metabolic disorder. In this study, we used ultrasonic processing to isolate four FB extracts (water extract, alcohol extract, proteins and residues) and examined their beneficial and detrimental effects. These extracts were separately mixed with commercial feed and fed to grass carp (Ctenopharyngodon idellus) using whole FB and commercial feed as controls. After fish were fed one of the six experimental diets for 50 d and 100 d, we evaluated the growth and hematological parameters, activities of metabolic enzymes, hepatopancreatic histology and oxidative response, and lipid metabolism. Results showed that both whole FB and FB residues caused growth retardation and hepatopancreas damage (P < 0.05), whereas growth performance was improved in the FB water and alcohol extract groups compared to the whole FB group. Although the FB water extract negatively affected the number and morphological parameters of red blood cells (P < 0.05), the hematological damage was less pronounced than that of the whole FB group. Excessive hepatopancreatic fat accumulation was found in the whole FB, FB alcohol extract and FB residues groups. Moreover, serious hepatopancreas damages were observed in the FB residues group. These results suggest that the beneficial and detrimental components of FB were successfully separated in the four extracts, and the FB water extract would be the best choice for grass carp culture in terms of growth performance and health. The safety evaluation of the four FB extracts would facilitate further application of FB in aquatic feed.

Keywords: Ctenopharyngodon idellus; Extracts; Hepatopancreas; Metabolism enzymes; Safety evaluation; Vicia faba.

Grants and funding

This study was funded by the Modern Agro-industry Technology Research System (No. CARS-45-21). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.