Francisco de Matos Dantas's research while affiliated with Universidade do Estado do Amazonas and other places

The production of silage using fish viscera can be carried out with straightforward methods and permits the exploitation of nutrients that are usually discarded. This process fosters the concept of circular aquaculture. The aim of this study was to evaluate the inclusion of increasing levels of fish viscera silage (VS) on the physical quality of the feed pellets and their effects on their growth performance, health parameters and on economic indices when the experimental extruded feed was offered to tambaqui. A fermented fish VS produced in-house was included in increasing levels on a wet-basis in the formulation of five experimental diets (VS 0%, VS 5%; VS 10%; VS 15% and VS 20%). Juvenile tambaqui (~22.6 g) were stocked in fibreglass tanks of 700 L (n = 4; 21 fish per tank) with a recirculation system and the five experimental diets were attributed in a completely randomized design. The fish were fed with the experimental diets (to apparent satiation) for 13 weeks. At the end of the trial, no significant differences were observed for production performance. Fish fed with the highest inclusion level of VS presented the highest concentration of plasma cholesterol, but this was still within acceptable values for this species. The inclusion of fish VS in diets for juvenile tambaqui reduced the activity of the plasma ALT enzyme, confirming normal liver function. Extruded feed containing fish VS had a production cost of US$ 0.95 per kg, which does not significantly impact the economic indices. Up to 20% of fish VS can be included in the extruded feed formulation for juvenile tambaqui without impairing growth performance or affecting health parameters. K E Y W O R D S feed extrusion, fermented fish silage, fish by-products, fish hydrolysis, fish viscera J Anim Physiol Anim Nutr. 2024;1-13. wileyonlinelibrary.com/journal/jpn | 1

Simple Summary This study focused on developing feed based on locally sourced ingredients for tambaqui farming in the Amazon. We tested diet formulations with varying levels (0% to 100%) of defatted black soldier fly larvae meal as a replacement for traditional fish meal, combined with cassava by-products (tuber residues, peel, and leaves). A traditional diet was used as the control. Neither diet rejection nor mortality were observed. Fish fed all the experimental diets presented similar feed conversion and protein efficiency rates. However, these results were worse than those observed in the fish fed a traditional diet. There were no significant differences in the overall body composition of the fish, but those fed cassava by-products developed yellow-colored fillets due to the carotenoids in the cassava leaves. The black soldier fly larvae meal and cassava by-products are a viable way to support sustainable aquaculture in the Amazon; however, we recommend further research to optimize the diet formulation, particularly a reduction in the proportion of cassava leaves, in order to improve digestibility and minimize the impact on fillet color. Abstract The aim of this study was to produce feed based on locally sourced ingredients for tambaqui farming in Amazon. Diets were formulated with increasing levels (0, 25, 50, 75 and 100%) of defatted black soldier fly larvae meal (BSFL) as a replacement for fish meal (FM), and cassava by-products in the same proportion (tuber residues, peel and leaves). A conventional diet (CO) was used as the control. Juvenile tambaqui (24.61 ± 1.14 g) were housed in 24 tanks in a recirculation aquaculture system. Neither diet rejection nor mortality were observed. Fish fed cassava by-products showed similar feed conversion rates (FCR 1.76); however, these values were worse than those observed in fish fed the CO (FCR 1.33). No differences were observed in the whole-body composition of the fish. The fillets of fish fed cassava by-products had a yellow color due the carotenoids present in the leaves. Dietary BSFL and cassava by-products can contribute to the sustainability of Amazonian aquaculture. Further studies with a lower proportion of cassava leaves in the diet formulation are recommended so as to ensure enhanced diet digestibility and less impact on the color of the fillets.

The pirarucu (Arapaima gigas) is a fast-growing Amazonian species of high commercial value. The present study aimed to determine the dietary crude protein (CP) level to promote maximum zootechnical performance for pirarucu fingerlings and as their resistance to Aeromonas hydrophila, as well as evaluate their hematological parameters. Pirarucu fingerlings (2.4 ± 0.08 g, 6.8 ± 0.52 cm) were distributed in 18 tanks (140 L, 40 fish per tank, n = 3) and fed six experimental diets consisting of increasing levels of CP: 300, 400, 450, 500, 550 and 650 g kg-1 in a completely randomized design. Data were submitted to one-way ANOVA (p < 0.05) and the ideal CP level for weight gain was determined using polynomial regression analysis. The dietary CP levels were evaluated using a quadratic polynomial regression and the level of 595 g kg-1 was determined for the best weight gain. The hematocrit of fish fed 300 g kg-1 was higher than in the other groups. No mortalities were observed after the 15-day bacterial challenge; however, number of pirarucu with bacterial damage on the pirarucu caudal fin was higher in the group that was fed the diet with 300 g kg-1. A dietary protein level of 618 g kg-1 is therefore recommended for providing maximum weight gain and immunological resistance in pirarucu fingerlings weighing 2.4-112.5 g.

The production of silage preserves fish viscera using simple techniques and allow the reutilization of nutrients that are usually discarded; thus, promoting circular aquaculture. The aim of this study was to evaluate the inclusion of increasing levels of fish viscera silage on the physical quality of the feed pellets, and the growth performance, health parameters, and economic analysis when tambaqui ( Colossoma macropomum ) were offered the experimental diets. A fermented fish viscera silage (5% yogurt; 15% molasses; 0.25% antioxidant) was included in the formulation at graded levels in a wet-basis (VS 0%, VS 5%; VS 10%; VS 15%, and VS 20%). Tambaqui (initial weight ~ 22.6 g) were stocked in a recirculation system and fed the experiment diets to apparent satiation for 13 week. At the end of the feeding trial, fish presented ~ 500% growth for all experimental groups. Average feed efficiency was 0.78, protein efficiency rate 2.28%, and relative growth rate 1.79%.day − 1 . Fish fed with the highest level of inclusion of viscera silage showed high concentrations of plasma cholesterol but with acceptable values for this species. The inclusion of fish viscera silage in diets for juveniles of tambaqui reduced the activity of the ALT enzyme, confirming normal liver function. Diets with fish viscera silage had a production cost of US$ 0.95 per kg, without significantly impacting on the economic indices. Up to 20% of fish viscera silage can be included in the extruded feed formulation to juveniles of tambaqui, without impairing growth performance and health parameters.

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.

The present study evaluated the effects of commercial guarana ( Paullinia cupana ) powder as a growth-promoter and natural antioxidant supplement in aquafeeds. In Experiment 1, fish were fed with graded levels of guarana powder (0, 1.25, 2.5, 5 and 10 g/kg) during 60 days. Growth, hemato-immunological and biochemical performance were evaluated in healthy fish and in fish after infection by Aeromonas jandaei . In Experiment 2, the supplemented feed was stored for 90 days, in which tests were carried out regarding the quantity of phenolic compounds and the inhibition of lipid peroxidation. As a result of Experiment 1, fish fed guarana-supplemented diets and infected by A . jandaei presented better parameters of leukocyte respiratory activity, total proteins, globulin, albumin, alanine aminotransferase (ALT), leukocytes, lymphocytes, neutrophils, monocytes and thrombocytes. As a result of Experiment 2, levels of phenolic compounds were not altered (p > 0.05) by the guarana-supplemented diets. An increase in the concentration of malondialdehyde (MDA) and a lower oxygen radical absorbance capacity (ORAC) was observed in the fish fed diets with the highest level of guarana supplementation. As conclusion, guarana did not impair productivity and revealed a possible cytoprotective and hepatoprotective effect in fish infected by A . jandaei . Therefore, guarana seems to be an interesting additive to be included at levels of up to 1% in special feeds to be used prior to stressful situations in aquaculture. Additionally, guarana had no protective effect against lipid peroxidation and showed a pro-oxidant effect in diets with higher supplementation levels.

Black soldier fly (BSF, Hermetia illucens) meal is a prominent ingredient to keep up with the increasing demand of protein sources for aquafeeds. This study evaluated the digestibility of defatted BSF larvae meal (DBSFL) by indirect method, growth performance, haematological parameters, and carcass composition of tambaqui (Colossoma macropomum) fed diets containing DBSFL. The apparent digestibility coefficient of protein from DBSFL was 84.2%, corresponding to 42.9% of digestible protein. For the feeding trial, juvenile tambaqui (3.25 ± 0.01 g) were randomly distributed in 18 experimental units (100 L; n = 3; 27 fish/tank) in a recirculation system. Fish were fed to apparent satiation for 60 days with isoproteic and isocaloric diets containing 0%, 6%, 12%, 18%, 24% or 30% of DBSFL meal. At the end of feeding trial, fish length and weight were recorded; blood samples were drawn from caudal vein of three fish per tank, and three fish from each replicate were euthanized for analysis of carcass proximate composition. The inclusion of up to 30% DBSFL meal did not impair tambaqui growth performance and fish body composition. The blood cholesterol level of the fish fed diet with 30% DBSFL inclusion was higher, but within the limits recorded for that species. DBSFL meal seems to be an interesting and safe protein source for tambaqui farming. The use of this ingredient as protein source can encourage the circular economy by promoting environmental sustainability.

The green water technique uses microalgae in the water of indoor larviculture, providing a darker environment to favor fish growth, welfare and health. We evaluated growth performance and locomotor activity after light exposure of pirarucu (Arapaima gigas) larvae reared in green or clear water. During one test, pirarucu larvae (3.6 ± 0.3 cm; 0.36 ± 0.1 g) were reared in 50-L circular tanks (n = 3 per treatment, 50 larvae per tank) in a static system containing green water [microalgae (w3algae; Bernaqua® 10 g m-3) added] or clear water (control). Fish weaning was achieved by co-feeding with Artemia nauplii and microdiets for seven days until full microdiet substitution. Larvae were biometrically evaluated on days 10, 17 and 24 to assess growth performance. In a second test, the locomotor activity of the larvae was analyzed before and after light exposure (1400 ± 60 lx) for 48 h according to an ethogram. After 24 days, the larvae reared in the green water were significantly heavier than those from the clear water, and displayed significantly fewer circular swimming movements. Body cortisol increased in both groups after light exposure. The microalgae provided an additional food source for larvae, with positive impact on growth until day 17 of larviculture. Green water can be a strategy to achieve better results in pirarucu larviculture, especially during and up to 10 days after the co-feeding period.

The aim of this study was to evaluate the survival and growth of Arapaima gigas larvae reared in slightly salinized water. Pirarucu larvae (183.1 ± 41.2 mg and 3.4 ± 0.3 cm) were stocked in PVC tanks (20 L; n = 4; 40 larvae per tank) in a static system. A. gigas larvae were reared in increasing levels of salinized water (0, 1, 2, 3 and 4‰) for a period of 15 days. Fish were fed six times a day with Artemia nauplii (2,900 nauplii per larvae per meal in the beginning). The salinized water increased by at least four times the Artemia nauplii lifespan, which prolonged the time of live food supply to Arapaima larvae. Pirarucu larvae kept in freshwater presented the lowest values in weight gain, final weight and survival. Larvae reared in water with 4‰ of salinized water showed the highest final weight. Slightly salinized water enhances the growth and survival of A. gigas larvae and it can be a simple practice with low cost that can be applied in the routine of pirarucu larviculture.