R Adharyan Islamy¹, Veryl Hasan^2,3,4*, Fitri Sil Valen⁵, Ahmad Syazni Kamarudin⁴, Norshida Ismail⁴, Michael Czech⁶, Nurul Murmainnah⁷

¹Aquaculture (Kediri City Kampus), Department of Fisheries and Marine Resources Management, Faculty of Fisheries and Marine Sciences, Brawijaya University, Jl. Pringgodani, Kediri City 64111, East Java, Indonesia

²Department of Aquaculture, Faculty of Fisheries and Marine Science, Airlangga University. Jl. Mulyosari, Surabaya 60113, East Java, Indonesia

³Research Group of Environment and Fisheries Resources Management, Faculty of Fisheries and Marine Science, Airlangga University. Jl. Mulyosari, Surabaya 60113, East Java, Indonesia

⁴School of Animal Science, Aquatic Science and Environment, Universiti Sultan Zainal Abidin, Besut Campus, Besut 22200, Terengganu, Malaysia

⁵Aquaculture Department, Agriculture Fisheries and Biology Faculty, Bangka Belitung University, Gang IV No.1, Balun Ijuk, Merawang District, Bangka Regency, Bangka Belitung Islands 33172, Indonesia

⁶Institute of Hydrobiology and Aquatic Ecosystem Management, BOKU University, Vienna, Austria

⁷Doctoral Program of Agricultural Sciences, Faculty of Agriculture, Brawijaya University, Jl. Veteran, Ketawanggede, Lowokwaru District, Malang City, East Java 65145, Indonesia

 

*Corresponding author’s email: veryl.hasan@fpk.unair.ac.id

Received: 16 January 2026 / Revised: 13 April 2026 / Accepted: 22 April 2026 / Published Online: 09 May 2026

 

Abstract

 

The limited availability and increasing cost of conventional protein sources have encouraged the use of alternative feedstocks, including plant-based materials, for sustainable aquaculture feed production. However, many underutilized plants have low protein content or quality and/or contain high levels of anti-nutritional factors that limit their use in feed. This study aimed to determine the best level of yeast inoculum to use in fermentation of Alternanthera sessilis leaves and to evaluate the effects on nutritional composition, essential amino acid availability, anti-nutritional factors, and functional properties. Fermentation using Rhizopus spp. was carried out at inoculum levels of 0.0, 0.5, 1.0, 1.5, and 2.0% (w/w), followed by analyses of proximate composition, essential amino acid profile, anti-nutritional factors, fermentation efficiency, and antioxidant activity. The results showed that fermentation significantly increased crude protein content, total essential amino acids, particularly lysine and leucine, as well as degree of hydrolysis, soluble protein, and antioxidant activity. At the same time, phytate, tannin, and oxalate contents were markedly reduced. Most nutritional and functional improvements increased with inoculum level and reached a plateau at higher doses. Based on an integrated overall nutritional score, the 1.5% inoculum level provided the best balance between nutritional enhancement, amino acid bioavailability, and functional quality. These findings indicate that fermentation is an effective approach to improve the nutritional value of A. sessilis leaves and supports their potential use as a sustainable plant-based ingredient for aquaculture feed.

 

Keywords: A. sessilis, Anti-nutritional factors, Aquaculture nutrition, Cichlidae, Growth performance, Rhizopus spp., Solid-state fermentation

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