The aim of this study was to evaluate the physiological, zootechnical, and environmental benefits of the use of growth-promoting virginiamycin in the pirarucu diet. The research was conducted at the Carlos Eduardo Matiazze Fish Center, Federal University of Rondônia. In this study, 96 pirarucu fish were distributed in excavated nursery, divided into two treatment groups, control (0.0 mg kg−1) and treatment (75.0 mg kg−1) of feed with virginiamycin, with 8 replications in a completely randomized design. With virginiamycin being incorporated into commercial feed, for 107 days of cultivation, the fish were slaughtered with an average weight of 9.18 kg. Carcass weight, flesh, residues, and internal organs/guts were evaluated to calculate slaughter yields, Spearman’s correlation, and subsequently regression. For the quantification of micronuclei, a count of 1,000 cells per blade was determined. The means of the results obtained were contrasted by the Student’s t-test (α = 0.05). Virginiamycin did not cause oscillations in the limnological variables of the nursery but could reduce micronucleated erythrocytes. The average yields in carcass, flesh, and waste were 67.43, 53.4, and 43.14%, respectively. Virginiamycin provided strong correlations (ρ2) for better productive yields and lower slaughter residue. The hepatosomatic index indicated a strong relationship between liver weight and fat. Virginiamycin may be recommended for fish farming in pirarucu fattening because it contributes to the productive efficiency and sustainability of the fish farm system.

The aimed of the study was to evaluate the caloric value as a function of the proximal composition and correlate the selling price with the nutritional values ​​of commercial cuts of tambaqui (Colossoma macropomum) and pirarucu (Arapaima gigas) in different weight classes. The sample collections were performed in two processing units located in the state of Rondônia, Brazil. Were 200 tambaquis in five weight classes were studied. And, were 77 pirarucus were studied in seven weight classes. The design was completely randomized, with processing carried out in triplicate. The Kruskal-Wallis test (α=0.05) was used to compare the averages and the Spearman correlation (ρ) between price and nutrients. The commercial cuts with the highest caloric value were the tambaqui filet (145.70 kcal/100g) and the pirarucu filet mignon (119.11 kcal/100g) (p<0.05). And the less caloric commercial cuts were steak of tambaqui (100.47 kcal/100g) and pirarucu loin 102.01 kcal/100g) (p<0.05). It was also observed that the variables caloric value and protein content did not correlate with the price of the kilo of fish for the different commercial cuts, which leads to infer that, possibly, the sensorial, market and cultural factors were responsible for the price variations. Regarding the caloric value according to the composition of the tambaqui, the Class 4 was the most efficient category for production and commercialization. And in the composition of the pirarucu, the Class 4 presented satisfactory values of proteins and lipids and a good percentage of mineral matter.

The aimed of this study was to evaluate the mineral composition in commercial cuts of tambaqui (Colossoma macropomum) and pirarucu (Arapaima gigas). Were compared to the minimum values of daily consumption of minerals recommended by the World Health Organization (WHO). The experimental design was completely randomized, with processing performed in triplicate. Data were submitted to ANOVA. If ANOVA appeared statistically significant (α=0.05), the means were compared by Tukey’s Test. There was a difference (p<0.05) between commercial cuts of the tambaqui for different minerals. Tambaqui ribs and band presented the highest values of total iron 1.08 ± 0.12 mg/100g compared to other commercial cuts. The mineral elements Na+, K+, Ca2+ and Mg2+ expressed the highest values for the tambaqui steak, 301.00 ± 80.58, 457.00 ± 129.33, 36.00 ± 4.36 and 46.90 ± 4.68 mg/100g, respectively. There was a difference (p<0.05) between commercial cuts of the pirarucu for different minerals. The mineral elements Total Iron, Na+, K+ and Ca2+ expressed the highest values for pirarucu loin, 0.80 ± 0.07, 406.00 ± 117.50, 529.30 ± 130.58 and 32.00 ± 5.12 mg/100g, respectively. However, Mg2+ expressed a higher value for pirarucu tail fillet 37.10 ± 4.99 mg/100g. The tambaqui steak and pirarucu loin were the cuts that best met the minimum needs for mineral supply.

This study aimed to determine the mineral composition, fatty acid profile, omegas and lipid quality indexes in the visceral fat residues of tambaqui (C. macropomum). Three pieces of visceral fat were collected from 20 fish weighing 1.10 ± 0.10 kg, which were homogenized and sent for compositional analysis. Minerals were determined by AOAC Official method 969.23 and 968.08. The fatty acids were grouped to calculate the ∑PUFAs/∑SFAs fatty acids ratio and the proportion of polyunsaturated fatty acids ∑PUFAs (n-6/n-3), atherogenicity indixes (AI) were calculated, thrombogenicity (TI), and ratio between hypocholesterolemic and hypercholesterolemic fatty acids (HH). Mineral elements were found, 0.68 ± 0.015 mg/100g of total iron, 159.16 ± 14.32 mg/100g of Na+, 63.90 ± 5.11 mg/100g of K+, 10.28 ± 0. 62 mg/100g of Ca2+and 7.31 ± 0.58 mg/100g of Mg2+. As for fatty acids, 40.10% of SFAs, 38.10% of MUFAs and 21.80% of PUFAs. The calculations indicated significant values of omegas, 3, 6, 7 and n-7. There were ∑PUFAs/∑SFAs ratios of 1.84 and ∑PUFAs(n-6/n-3) of 6.22, with an AI of 0.50 and a TI of 0.93 and HH of 2.16. The 1.0 ± 0.10 kg tambaqui visceral fat residues can be evaluated as having high nutritional value, in addition to being a viable option for oil extraction and inclusion in animal feed.

It is important to know the nutritional composition of the fish, especially the nutritional value of the commercial cuts most consumed by the population. The aimed of this study was to evaluate the chemical composition of commercial tambaqui (Colossoma macropomum) cuts in different classes of body weight. The sample collections were carried out in processing units in two municipalities in the state of Rondônia, Brazil.  The Data on 200 fish were recorded, with weight ranging from 1000 to 4700 g. Five classes of body weight were established, class 1 - below 1.2 kg; class 2 - from 1.21 to 1.8 kg; class 3 - from 1.81 to 2.4 kg; class 4 - from 2.41 to 3.5 kg; class 5 - over 3.5kg. The commercial cuts were lyophilized and intended for chemical analysis. The Kruskal-Wallis test (α=0.05) was used to compare the averages. The composition of commercial cuts was different in weight classes (p<0.05). The filet presented more representative values in mineral matter, crude protein and total lipids and lower humidity for class 4 (from 2.41 to 3.5 kg). The classes 1 and 5 (below 1.2 and over 3.5 kg) were different (p<0.05) in relation to the lipid and moisture content in the commercial filet and rib cuts. The tambaqui steak in class 4 have a higher lipid content compared to the average of the lightest body weight classes, 9.99 vs 4.50%, in addition to having a lower moisture content (p<0.05). The tambaqui band was different (p<0.05) in relation to nutritional components between body weight classes, with class 4 being richer in minerals, crude protein and lipids in dry matter. Therefore, the class 4 was the most efficient (p<0.05) for production and commercialization. Because the tambaquis with body weight between 2.4 to 3.5 kg stood out in relation to the nutritional components in the different commercial cuts.