Use of glycerol in fish nutrition: a review

Abstract

Crude glycerol and its purified and synthesized forms derived from biodiesel production are non‐toxic, biodegradable, biocompatible and versatile, and can be converted into various chemicals or products for biological use. Among the possible uses, there is its use in fish feeding, due to the chemical and nutritional composition, for being classified as energetic food and has low cost. The possibility of using glycerol in fish diets has been motivated by increasing maize prices, the excessive amount of glycerol produced and its processing costs for other purposes. Glycerol use in fish diet formulations is feasible, provided that certain factors be evaluated, such as digestibility and inclusion levels. In this context, this review discussed the main aspects that must be taken into account regarding glycerol use in fish diets, such as the characteristics and chemical composition of its categories, their fish metabolism pathways and their influence on fish plasma glucose. Crude glycerol or glycerine displays good potential for use in fish feed, as it contains adequate energy concentrations and can replace part of fish feed maize. However, it is evident that assessments concerning specific physiological phases, such as fish in reproductive phases, as well glycerol stability in water, are required.

Biodiesel‐derived glycerol as a dietary maize replacement for silver catfish ( Rhamdia quelen ) during the fattening phase

“…Ethanol fuel production from maize has led to increasing costs. Thus, replacing maize with a cheaper ingredient can avoid high fish feeding costs (Mauerwerk et al, 2020). However, for crude glycerol to be a viable alternative for industries that produce aquaculture feed, its production must be regulated and its quality standardized, to ensure food safety, animal welfare and aquaculture productivity (Santos et al, 2019).…”

“…Thus, dietary glycerol maize replacement in silver catfish farming during the fattening phase is a safe practice, as no productive performance parameters or animal health are affected. The possibility of replacing dietary maize in omnivorous fish diets, which are very common in Brazil, as well as in other regions worldwide, is vital, first, because maize is used for human consumption, so this would reduce food competition, and second, due to lower fish feeding costs, as replacing maize with a cheaper ingredient is advantageous (Mauerwerk et al, 2020).…”

“…The apparent digestibility values of this ingredient have been investigated for different species, including Nile tilapia (Oreochromis nilotucus) (Gonçalves et al, 2015;Meurer et al, 2012Meurer et al, , 2016Neu et al, 2012), silver catfish, pacu (Balen et al, 2014) and curimbatá (Balen et al, 2017), and the obtained results indicate that glycerol is considered an adequate energy source for these fish species (Mauerwerk et al, 2020).…”

On the Utilization of Dietary Glycerol in Carnivorous Fish—Part II: Insights Into Lipid Metabolism of Rainbow Trout (Oncorhynchus mykiss) and European Seabass (Dicentrarchus labrax)

“…The use of glycerol in fish feed was recently reviewed (Mauerwerk et al, 2021a) but studies and insight into lipid metabolism are scarce and its putative lipogenic potential is yet to be evaluated thoroughly. Early studies with rainbow trout (Oncorhynchus mykiss) reported that glycerol was not an effective precursor for lipogenesis (Menton et al, 1986) but since then evidence has been presented that this may not be the case in other species and/or dosages.…”