Owing to their availability, cost effectiveness and environmental-friendly nature, plant extracts are promising additives for fish farming. This study aims to determine the optimal dosage of fermented herbal extract (FHE)-composed of Morus alba (33.3%), Curcuma xanthorrhiza (33.3%), and Boesenbergia rotunda (33.3%)-for growth enhancement and feed utilisation efficiency of Oreochromis niloticus fingerlings. Fermentation was conducted using probiotics Lactobacillus casei (Yakult®, Tokyo, Japan) and Saccharomyces cereviceae (commercial baker's yeast). The FHE was high in flavonoid and alkaloid, vitamin C, potassium, natrium, lipase and protease. Four doses of FHE treatments, namely treatment A (0 mg/kg of feed); treatment B (100 mg/kg of feed); treatment C (300 mg/kg of feed); treatment D (500 mg/kg of feed) were compared. After subjected to 35 days of culture, tilapias subjected to FHE-coated feed exhibited better weight gain (WG), specific growth rate (SGR), and feed efficiency (FE) compared to control. The best dosage that gave the highest growth and feed efficiency was treatment C (300 mg/kg of feed). Furthermore, the feed efficiencies of FHE-incorporated treatments were positively influenced by the increased in length and density of intestinal villi, number of goblet cells, lymphocytes, as well as nutrient retention to support growth. The results of this study indicate that FHE is a promising functional feed additive to stimulate growth and improve feed efficiency in tilapia farming.
Sea cucumbers have high economic value, and in most forms of trade, their body wall is typically the only part that is harvested and sold. The organs of the sea cucumber, collectively known as the viscera, are frequently discarded, contributing to land and water pollution. However, discarded sea cucumber viscera contain various nutrients that can be used in many applications. Therefore, this review highlights the biological and economic aspects of sea cucumbers, followed by a critical discussion of the nutritional value of their internal organs and possible applications, including as functional feed additives in the aquaculture industry, sources of natural testosterone for application in sex reversal and production of monosex population, of neuroprotective agents against central nervous system disorders and of cosmetic ingredients, especially for skin whitening and anti-ageing products. The review further highlights the valorisation potential of viscera to maximize their economic potential, thus providing an enormous prospect for reusing sea cucumber waste, thereby reducing the negative impact of the sea cucumber fishery sector on the environment.