Fish Viscera Silage: Production, Characterization, and Digestibility of Nutrients and Energy for Tambaqui Juveniles

Abstract

Fish viscera can be an important source of protein and energy for aquafeed, and its use contributes to circular aquaculture. The aim of this study was to produce acid and fermented silage from fish viscera to determine their nutritional value and the apparent digestibility coefficient of nutrients and energy for juvenile tambaqui (Colossoma macropomum). An acid silage and three fermented silages with different sources of carbohydrates (molasses, wheat bran, and cassava waste) were produced with 0.25% sorbic acid as an antifungal in the formulation. Silages presented an average of 55% dry matter, 62.9% lipids, and 12% crude protein. Leucine and lysine predominated as essential amino acids in the acid silage and fermented silages. Fish viscera silages presented EPA and DHA content from 5.4 to 17.8 and 1.7 to 8.9 mg.g−1 of lipids, respectively. The apparent digestibility coefficient (ADC) (indirect method) was above 82% for gross energy for all the formulations. The ADCs for protein were similar for the fermented silages, with a maximum 92% level for the fermented wheat bran silage. The bioconversion of fish viscera into silage makes it an energy ingredient for aquafeed that is well digested by tambaqui juveniles.

Comparison of amino acid release between enzymatic hydrolysis and acid autolysis of rainbow trout viscera

“…Regarding the FAA profile ( Table 3 ), the total percentage of Gln and Tyr fell while Glu, Leu and Lys were the most prevalent during the silage, in the case of glutamic acid finishing day 10 at 10.3 ± 0.3 % of the total FAA. The profile was similar to the one reported by Santana et al (2023) [ 31 ], where a 7-day acid silage of tambaqui viscera was carried out. Analysis of variance showed that there was a significant difference between days of silage in terms of the amino acid profile.…”

The Effects of Unconventional Feed Fermentation on Intestinal Oxidative Stress in Animals

“…Livestock and poultry processing by-products refer to the by-products produced during the slaughtering and processing of livestock and poultry, usually including bones, internal organs, fur, blood, and feathers [ 47 , 48 ]. These by-products are rich in nutrients and can be used to make various types of feed, providing comprehensive nutritional support for the animals.…”

Exploring Sustainable Aquafeed Alternatives with a Specific Focus on the Ensilaging Technology of Fish Waste

“…Because small peptides and free amino acids can be absorbed more easily than intact proteins and do not require prior digestion by pancreatic proteases, fish silage may be more digestible than fishmeal, as suggested by several studies [34,35]. Santana et al [35] reported that fish viscera can be converted into both acid and fermented silage, which is a well-digested energy ingredient for aquafeed due to the high fat (around 60%) content in dry matter.…”

“…Because small peptides and free amino acids can be absorbed more easily than intact proteins and do not require prior digestion by pancreatic proteases, fish silage may be more digestible than fishmeal, as suggested by several studies [34,35]. Santana et al [35] reported that fish viscera can be converted into both acid and fermented silage, which is a well-digested energy ingredient for aquafeed due to the high fat (around 60%) content in dry matter. The fermented silages produced with different sources of carbohydrates, such as molasses, wheat bran, and cassava waste, had a high protein content of 12% in terms of dry matter and were rich in essential amino acids, eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA), along with beneficial microorganisms.…”