Exploring the potential of Nile perch fish processing wastes for animal feed

Abstract

Nile perch fish is of a high socioeconomic importance and very popular on the international market for its numerous nutritional benefits (Asnake, 2018). There are seventeen Nile Perch fish processing along the Lake Victoria basin in Uganda with ten factories currently processing Nile perch fish for mainly export of fish fillets, fish maw, fats and skins. These factories produce over 38% of the total fish process as fish waste which includes the skin, bones, viscera, fat, scales, and wastewater. The viscera are mainly dumped on the ground or landfills which possess a serious negative impact on the environment, ecosystems and general human and animal health. This study aimed at finding the most appropriate and environmentally friendly way of converting Nile perch fish wastes (Viscera) into animal feeds. The approaches carried out involved using formic acid and molasses in a 2 x 3 factorial experimental design. The degree of protein hydrolysis and the nutritional composition of the fish silage were investigated. It was then found that adding 2% formic acid to minced Nile perch viscera and storing them for 5 days and then adding 15% rice bran to the resulting liquid silage provided the best alternative out of the those carried out to obtain animal feeds from Nile perch fish viscera. This study demonstrated that all Nile perch viscera obtained through processing could be sustainably converted into animal feeds. This could provide an effective and efficient way of managing Nile perch viscera which would ultimately protect the environment from pollution, provision of economic opportunities, improved livestock production and increase in trade, thereby promoting sustainable development and ultimately contributing to the bioeconomy concept. Bioeconomy is an economy that uses renewable biological resources such as plants and animals and converts them into food, feed, food raw materials, and energy (McCormick and Kautto, 2013) This is seen as an opportunity for the sustainable use of biological resources, which can help address sustainable development issues such as climate change and environmental degradation (Hausknost et al., 2017). However, additional experimental studies should be carried out to optimize the process of producing fish silage, determine the palatability of the animal feed silage, and the effect on the production efficiency and productivity of the animals that feed on the silage obtained from the Nile perch fish viscera.