Comparison of amino acid profiles of feeds and fish as a quick method for selection of feed ingredients: a case study for Colossoma macropomum (Cuvier)

The amino acid profile of Colossoma macropomum was determined. Indispensable amino acid levels were similar to those reported in other fish species. Suitability of local, Costa Rican, ingredients as protein sources for C. macropomum was evaluated based on their protein content and indispensable amino acid profile. It was calculated that, in a standard diet (40% protein. 25% fish meal), blood meal, soya meal, poultry byproducts, meat and bone meal, and meat meal can substitute more than 80% of the fish meal. More than 40% of the fish meal can be substituted by shrimp meal, pigeon pea, cotton meal, peanut oil cake, cow pea, corn gluten and water hyacinth. As differences between amino acid profiles between fish species seem to be small, promising alternative ingredients for C. macropomum might be equally interesting for formulation of feeds for other species. Soya meal is the currently used ingredient with the highest potential to substitute fish meal completely. Further research is needed to determine if the use of alternative ingredients is limited by constraints such as decreased feed digestibility, presence of anti-nutritional factors, additional production and processing costs.     

Feed consumption, growth and protein utilization of Colossoma macropomum (Cuvier) at different dietary fish meal/soya meal ratios

The effect of a gradual substitution of dietary fish meal protein by soya meal protein on growth, feed uptake and protein utilization of 1 g Colossoma macropomum (Cuvier) was studied at two different dietary protein levels. Growth rates of fish fed ad libitum 20 and 45% protein diets fluctuated between 41 and 49, and between 60 and 68 g kg^{-0 8} day^-1, respectively. Fish incorporated between 31 and 47% of the dietary protein in their body. Increased amounts of soya meal in the diet led to decreased feed uptake, higher body protein levels, lower ash levels and increased NPU values. If the low ash contents in the fish fed 100% soya diets are not prejudicial for health and growth of the fish in the long term, soya meal must be considered a superior protein source for C. macropomum. The high growth and the efficient use of the dietary protein indicate the C. macropomum is able to utilize soya protein more efficiently than other fish species.     

Tolerance response of tambaqui Colossoma macropomum (Cuvier) to water pH

Tambaqui Colossoma macropomum (Cuvier) is a fish of primary importance in Amazon aquaculture. It has been described as an acid‐resistant species that moves seasonally between white (muddy) water and black water rivers and enters the extremely dilute acidic areas of flooded jungle to feed during the rainy season. To analyse the pH tolerance of this species, tambaqui were exposed to three water pH levels for 40 days (pH 4.0, 6.0 and 8.0). The water was acidified slowly over 3 h, allowing the fish to acclimate. A similar protocol was used to adjust water pH to 8.0. No mortality was observed during the exposure period. Several haematological parameters were significantly changed in alkaline‐exposed animals, with significant decreases in haematocrit (20%), haemoglobin concentration (8%) and red blood cells (12%). Tambaqui showed severe blood variations when exposed to alkaline pH. Fish final weight, condition factor and specific growth rate (SGR) was inversely proportional to a pH increase, and SGR were higher for fish reared in acidic water. The relative insensitivity of tambaqui to low pH confirms its acid tolerance and is in accordance with its natural occurrence in black water habitats.     

Population dynamics and stock assessment of Colossoma macropomum caught in the Manacapuru Lake system (Amazon Basin,Brazil)

Colossoma macropomum is the second largest scaled fish in the Amazon basin. Reduced harvests in recent decades suggest that populations of this species are already overexploited in some areas. In this study, the population dynamics of C. macropomum was investigated using length and weight data for fish caught in the Manacapuru Lake system, a large ria lake located along the lower reach of the Solimões River. A total of 1270 individuals of C. macropomum with standard lengths varying from 17 to 62 cm and mean length of 31.0 ± 6.7 cm were sampled. Weights varied from 165 to 8195 g, and mean weight was 1148.3 ± 883.8 g. Maximum sustainable yield was estimated at 285.8 g recruit⁻¹, corresponding to a fishing mortality of 0.51 year⁻¹. A scenario analysis based on changes in fishing mortality and age at first capture, two parameters potentially addressed by fishing management strategies, suggested that any improvement in fishing yield depends on increases in age at first capture.     

Feeding trials with herbivorous and omnivorous Amazonian fishes

Fish of three species were fed on diets containing 30% total protein of which 0–95.5% was animal (fish meal) protein. Mylossoma sp. and Semaprochilodus theraponura showed the best growth rates (27 and 43.5% weight gain in 23 days) when only 25% of the protein was of animal origin, and Colossoma macropomum grew best (28.1% weight gain in 23 days) on a diet with no animal protein.Brycon melanopterum, an omnivore, grew well (50.5% weight gain in 29 days) on a diet containing 35% total protein of which 50% was of animal origin.     

Finishing plant diet supplemented with microalgae meal increases the docosahexaenoic acid content in Colossoma macropomum flesh

The need for a sustainable aquaculture is increasing the use of plant ingredients in replacement to fishmeal and fish oil in diets for tambaqui Colossoma macropomum, which is leading to not detectable levels of docosahexaenoic acid (DHA) in its flesh. We evaluated the effect of a finishing plant diet supplemented with 5% of microalgae meal from Schizochytrium sp. (MD) on tambaqui growth, on proximal composition and fatty acid content of its flesh, comparing it to a non‐supplemented diet. One hundred and sixty‐two fish (489.67 g) were distributed into six tanks (2,000 L) and fed the experimental diets for a 90‐day period. Three fish per tank were euthanized for analyses every 15 days. The MD did not affect the growth and proximal composition of fish flesh. The MD increased the DHA content (from 14.81 to 38.60 mg/g of lipids) and the n‐3:n‐6 ratio (from 0.16 to 0.51) in the flesh of fish, beginning on the 15th day and reaching the highest DHA content on the 71st day (39.81 mg/g of lipids). We recommend C. macropomum to be fed with a finishing diet supplemented with microalgae meal for 71 days before slaughter to improve the DHA content and n‐3:n‐6 ratio in the flesh.     

The effect of dietary protein level on growth, protein utilization and body composition of Colossoma macropomum (Cuvier)

Three size groups of Colossoma macropomum were submitted to a 4-week growth trial. Five nearly isocaloric (18.8-21.0 kJ g^?1) diets with protein concentrations ranging between 17 and 64% were administrated at a fixed, near satiation level. Maximum growth was 6.6, 3.6 and 1.9 g protein kg^?0.8 day^?1 for 5, 50 and 125 g fish, respectively. The protein requirement to achieve maximum growth decreased from 28.9 g protein kg^?0.8 day^?1 for 5 g fish to 11.7 g kg^?0.8 day^?1 for 125 g fish. Possibly because of its high growth rate. C. macropomum needs a slightly higher dietary P/E ration (25.4-27.9 mg protein kJ^?1) to obtain maximal growth than most other fishes. The relation between protein ration and protein gain was studied by a quadratic regression model. In fish receiving protein rations equal or below rations resulting in maximal growth, protein ration and protein gain were almost linearly related. The model showed that the portion of the dietary protein which is digested decreases with increasing protein ration. Body protein content increased and body lipid content decreased with feed protein level. Fish fed a 17% protein diet deposited as much as 18% lipid.     

Effects of fisheries zoning and environmental characteristics on population parameters of the tambaqui (Colossoma macropomum) in managed floodplain lakes in the Central Amazon

Fisheries zoning and the influence of biotic and abiotic factors in the spatial distribution of Colossoma macropomum (Cuvier) in the Piagaçu‐Purus Sustainable Development Reserve, Central Amazon, during 2012–2013 were evaluated. The relative abundance and population parameters of the C. macropomum were compared between conservation (no‐take zone) and fishing (open to fishing zone) lakes. The fish were collected by experimental fishing in 2012 and 2013. A total of 296 individuals were captured, most of which were from the conservation lakes (62.8%). Higher proportions of larger adults and individuals were found in the conservation lakes, although no significant difference in the average C. macropomum catch‐per‐unit‐effort was found between the lake categories. Abundance was positively influenced by zooplankton density (r² = 0.53, P < 0.03). Therefore, it is hypothesised that conservation lakes may serve as refugia for juveniles due to the high availability of planktonic food available during the dry season. Although there were environmental differences between the two lake types, the relative success of management models that use no‐take zones in freshwater habitats was highlighted. Finally, the importance of zooplankton as a factor in the distribution of C. macropomum among floodplain lakes was emphasised.     

Feeding,growth, and blood chemistry of the tambaqui (Colossoma macropomum) held under self-feeding and time-restricted automatic feeding conditions

This work evaluated the effects of food frequencies and self-feeding on the behavior, performance, and blood biochemistry of Colossoma macropomum. Juveniles weighing 3.63?±?0.05 g were distributed in 27 aquariums (40 L), with six fish per aquarium, to evaluate nine treatments in three replications in a 12L:12D photoperiod. The treatments were 24-h self-feeding (SF); daytime self-feeding at will (SFD); nighttime self-feeding at will (SFN); and feeding at fixed frequencies of two (2D), four (4D), and six times (6D) daytime and twice (2 N), four (4 N), and six times (6 N) nightly. The treatments were offered in automatic feeders, with fixed frequencies programmed. Extruded commercial feed, with 46% protein, was used. The experimental period was 40 days. In the SF treatment, the animals exhibited 95.7% nocturnal and 4.3% diurnal feeding activity (p?<?0.05). In the treatment SFD and SFN, the animals showed feeding activity throughout the day and night. Final weight, weight gain, and total feed intake were higher for animals at fixed daytime and nighttime frequencies (p?<?0.05). Feed conversion was better for animals in SF, SFD, 4D, SFN, and 4 N (0.89, 0.76, 0.91, 0.85, and 0.88, respectively) (p?<?0.05). Cholesterol and high-density lipoproteins were lower for fish in SF, SFN, 2 N, 4 N, and 6 N (p?<?0.05). SF treatment animals had lower triglyceride content, 154.20 mg dL^?1 (p?<?0.05). Colossoma macropomum has nocturnal food preferences, however, with remarkable plasticity. Juveniles of this species fed four times during the day or night show good performance. Dietary patterns influenced the blood metabolic indicators of this species and the periods studied.

     

Effects of a nanoemulsion with Copaifera officinalis oleoresin against monogenean parasites of Colossoma macropomum: A Neotropical Serrasalmidae

Monogeneans are ectoparasites that may cause losses in production and productivity in the aquaculture of Colossoma macropomum. Chemotherapeutics used in aquaculture usually have major adverse effects on fish; hence, the use of essential oils has been considered advantageous, but these are not soluble in water. Thus, the use of nanostructures to enhance water solubility of compounds and improve bioactivity may be very promising. This study investigated the antiparasitic activity of nanoemulsion prepared with Copaifera officinalis oleoresin (50, 100, 150, 200 and 300 mg/L), against monogenean parasites from the gills of C. macropomum. The particle size distribution and zeta potential suggested that a potentially kinetic stable system was generated. The nanoemulsion from C. officinalis oleoresin achieved high efficacy (100%) at low concentrations (200 and 300 mg/L) after 15 min of exposure. This was the first time that a nanoemulsion was generated from C. officinalis oleoresin using a solvent‐free, non‐heating and low‐energy method. Moreover, this was the first time that an antiparasitic against monogeneans on fish gills, based on nanoemulsion of C. officinalis oleoresin, was tested.     

Nanoemulsions with oleoresin of Copaifera reticulata (Leguminosae) improve anthelmintic efficacy in the control of monogenean parasites when compared to oleoresin without nanoformulation

This study compared the in vitro anthelmintic activity of Copaifera reticulata oleoresin (200, 400, 600, 800 and 1,000 mg/L) and of nanoemulsions prepared with this oleoresin (50, 100, 150, 200 and 250 mg/L) against monogeneans on the gills of Colossoma macropomum. The major compounds present in the oleoresin of C. reticulata were γ-macrocarpene (14.2%), α-bergamotene (13.6%), β-selinene (13.4%) and β-caryophyllene (11.7%). All concentrations of the nanoemulsion and the oleoresin without nanoformulation showed anthelmintic efficacy against monogeneans, and higher concentrations led to more rapid parasite mortality. Structural damages to the tegument of the parasites exposed to C. reticulata oleoresin were observed with scanning electron microscopy. At two hours of exposure, fish showed 100% tolerance to all nanoemulsion concentrations used in the in vitro assays, whereas 100% mortality was shown in the fish exposed to the oleoresin without nanoformulation after one hour. The results of this study suggest that nanoemulsions with oleoresin of C. reticulata have advantages in the control and treatment of monogenean infections in C. macropomum when compared to the oleoresin without nanoformulation. In addition, since nanoemulsions with the C. reticulata oleoresin are safe to control monogeneans, the efficacy of these nanoformulations may be assayed in therapeutic baths to treat C. macropomum infected by monogeneans.     

Modelling growth of Colossoma macropomum (Cuvier): comparison of an empirical and an explanatory model

Accumulated data from growth experiments on the nutrition of Colossoma macropomum (Cuvier) were analysed using an empirical (linear regression) and an explanatory model called the fish growth simulator (FGS). Both methods gave satisfactory results. Differences between predicted and observed values fluctuated less with the FGS. However, the linear regression method is simple and results are easily translated to practical recommendations. The FGS covered a wider range of experimental conditions than the linear regression method. Both linear regression and the FGS stressed the importance of dietary protein in growth of C, macropomum. Dietary protein concentration is the main explaining variable of ad libitum feed uptake, while protein ration is the main variable determining growth. Dietary protein concentration also affects body protein and body lipid content. Protein utilization efficiency data indicate that substitution of fishmeal by soya meal increases dietary protein quality. Although C, macropomum can thrive under less than optimal conditions, a high-quality, high-protein diet is required for maximal growth and optimal feed utilization.     

Albendazole,levamisole and ivermectin are effective against monogeneans of Colossoma macropomum (Pisces: Serrasalmidae)

This study evaluated the efficacy of albendazole, ivermectin, levamisole, mebendazole and praziquantel on monogeneans of Colossoma macropomum, based on in vitro and in vivo assays. In vitro assays indicated that albendazole (500, 100, 1,500 and 2,000 mg/L), ivermectin (200, 250, 300 and 350 mg/L) and levamisole (50, 75, 100 and 125 mg/L) were 100% effective against Anacanthorus spatulatus, Notozothecium janauachensis, Mymarothecium boegeri and Linguadactyloides brinkmanni, while mebendazole (125, 150, 175 and 200 mg/L) and praziquantel (5, 10, 15 and 20 mg/L) were ineffective. Fish mortality in 24 hr therapeutic baths with 500 mg/L of albendazole was 6.6%, but the behaviour of the animals remained unchanged, while 200 mg/L of ivermectin caused lethargy, signs of hypoxia and 100% mortality within 2 hr, and 125 mg/L of levamisole caused no mortality. The efficacy of 500 mg/L of albendazole was 48.6% in the 24 hr baths, while that of 125 mg/L levamisole was 88.2%. Although ivermectin showed in vitro efficacy, the lowest concentration used in baths was highly toxic to fish. Therefore, we recommend the use of 125 mg/L of levamisole to control and treat monogenean infestations on C. macropomum in fish farming.     

Characterization of the fishery in river communities in the low-Solimões/high-Amazon region

Questionnaires were used to collect data from the low-Solimões/high-Amazon region, Brazil, between December 1992 and February 1994. Gillnets, fishing rods and castnets were the preferred gear used. Gillnets were used throughout the year whilst other gears were used only in certain periods of the year. The fish caught tended to supply family needs but a high proportion were sold in regional markets. Curimatã (Prochilodus nigricans), pacu (various Myleinae) and ruelo (young Colossoma macropomum) were the most frequent species caught. Around 50% of the fish caught in these fisheries was consumed fresh, and the remainder was stored under ice or salted. Fish is the most important source of animal protein for this region, with an annual mean consumption rate of 550 g capita^?1 day^?1. The fishery has changed from a subsistence to a commercial scale, which was associated with increasing cattle ranching activities. This may have serious social and economic implications.     

Genetic basis of Colossoma macropomum broodstock: Perspectives for an improvement program

Tambaqui, Colossoma macropomum (CUVIER, 1818), is the most farmed fish in Brazil. Endemic to the Amazonas and Orinoco basins, it is currently raised in all Brazillian regions. The lack of basic genetic information on tambaqui broodstock has been one of the problems of improvement programs in the species. The goal of this study is to provide information on the genetic basis of tambaqui broodstock from six fish farms located in three different regions of Brazil for application in improvement programs. Thus, genetic analyses were conducted using 15 microsatellite loci. We observed that the broodstock of Biofish (NortB), Prosperidade (NortP), and Tajá (NortT) presented loss of genetic variability. However, their genetic diversity values are higher when compared with the broodstock from the AquaBrasil (improved, NortA) project, Brumado (SoutB), and Departamento Nacional de Obras Contra a Seca (DNOCS) (NorthD), respectively. Furthermore, the broodstock of DNOCS needs to be renovated or increased, and the AquaBrasil individuals need to be better evaluated to verify the improvement achieved in the improvement program. Thus, aimed at the improvement of tambaqui production in the fish farms analyzed, we recommend increasing the population size of the broodstock to avoid inbreeding.     

Essential oil of Lippia grata (Verbenaceae) is effective in the control of monogenean infections in Colossoma macropomum gills,a large Serrasalmidae fish from Amazon

This study investigated the efficacy of Lippia grata essential oil (EO) against monogeneans of Colossoma macropomum and effects on the haematology after immersion baths. In the in vitro assays, the efficacy of 100, 250, 350 and 700 mg/L of L. grata EO and two controls were tested, of which one control was with the cultivation tank water and the other was with the tank water and 70% ethyl alcohol. Composition of majority bioactive compounds in the EO was carvacrol (48.12%), p‐cymene (24.39%) and γ‐terpinene (2.49%). Anacanthorus spathulatus, Notozothecium janauachensis, Mymarothecium boegeri and Linguadactyloides brinkmanni obtained of fish gills showed 100% immobilization in the in vitro assays when exposed to 700 and 350 mg/L after 30 min and 2 hr respectively. Fish showed tolerance to 700 mg/L of the EO, which was used in therapeutic in three consecutive baths, which caused lamellar hyperplasia in C. macropomum gills. The 700 mg/L of the EO in the therapeutic baths showed an efficacy of 95.1% against the monogeneans and caused decrease in haemoglobin, whereas control fish showed a reduction in mean corpuscular haemoglobin concentration. Results indicated that 700 mg/L of L. grata EO is a safe and effective concentration to treat C. macropomum infected with monogeneans.     

Dietary available phosphorus requirement for tambaqui,Colossoma macropomum,juveniles based on growth,haematology and bone mineralization

An economical and efficient approach to reduce the impact of P discharge by aquaculture industry is to adjust the P level in fish feeds to the precise nutrient requirement at different growth stages in a digestible nutrient basis. However, P requirement seems to be species specific and affected by several physiological, dietary and environmental factors. Based on the importance of tambaqui (Colossoma macropomum) to Latin American aquaculture, we designed a 63‐day trial to evaluate the effect of available P (AP) levels on growth, nutrient digestibility, haematology and blood biochemical parameters, carcass proximate composition and bone mineralization. Quadruplicate groups of tambaqui juveniles (144 ± 2.0 g) were fed five isonitrogenous (278 g kg^?1 digestible protein) and isocaloric (13.5 Mj DE kg^?1) diets containing graded AP levels (3.0, 5.6, 7.5, 9.1 and 11.0 g kg^?1) following a completely randomized design. Dicalcium phosphate (DCP) was used as the main P source. No mortalities and signs of P deficiency were observed among the dietary treatments. A remarkably high P digestibility was observed in all plant‐based diets with a tendency of decreasing P digestibility with the increase in total P levels. Tambaqui seems to be able to grow well without inorganic P supplementation during the trials; however, this species required 7.0 g AP kg^?1 diet for proper bone mineralization. P supplementation had a limited effect on haematology and blood biochemistry of tambaqui. Ecological implications of natural feeding habit and evolutionary position of this species are further discussed, and new hypothesis are drawn based on our results.     

Eugenol as an efficacious anaesthetic for tambaqui, Colossoma macropomum (Cuvier)

Anaesthetics are important in fish culture to reduce handling stress and mortality. Eugenol is a promising anaesthetic because of its low cost, efficacy, safety margin for fish and lack of toxicity to humans. The goal of this study was to establish a protocol using eugenol as a fish anaesthetic for tambaqui Colossoma macropomum (Cuvier), and provide information for regulating authorities on establishing safety dosage protocols for its use. Juvenile and sub‐adult tambaqui were first individually exposed to doses of 35, 50, 65, 85, 100 or 135 mg L^?1 eugenol for 10 min. A second experiment examined the effect of the duration of exposure to eugenol on the time required for recovery and survival of tambaqui. A eugenol dose of 65 mg L^?1 was adequate to induce fish of both sizes into a surgical anaesthetic state, and recovery time was similar for dosages up to 100 mg L^?1. Exposure to the ideal dose (65 mg L^?1) for up to 30 min did not cause fish mortality. Fish blood glucose values were similar for all the tested eugenol doses as well as with the benzocaine control. The results show that eugenol is an efficient and safe anaesthetic for tambaqui.     

Effects of Carbohydrate‐Rich Alternative Feedstuffs on Growth,Survival, Body Composition,Hematology, and Nonspecific Immune Response of Black Pacu,Colossoma macropomum,and Red Pacu,Piaractus brachypomus

To facilitate economical culture of black pacu, Colossoma macropomum, and red pacu, Piaractus brachypomus, in the Amazon region of South America, we assessed locally available alternative energy sources for practical diets. We tested the effects of control diets (containing wheat products) versus diets with different Amazonian feedstuffs (yucca, Manihot sculenta, plantain, Musa paradisiaca, or pijuayo, Bactris gasipaes) on the performance of the pacus in three feeding trials. Black pacu (22.5 ± 0.03 g; Trial 1) or red pacu (2.56 ± 0.01 g; Trial 2) were fed diets containing 30% wheat bran (control) or cooked or uncooked yucca, plantain, or pijuayo for 12 wk. In Trial 3, larger black pacu (86.9 ± 6.4 g) were grown to market size in 24 wk on similar diets. Weight gain, feed conversion, survival, alternative complement activity, and lysozyme were similar among diets. Hepatosomatic index, liver glycogen, and dry matter were affected by diet in Trials 1 and 2, but effects were not consistent among trials. In Trial 3, protein efficiency ratio was lower in fish fed the diet containing wheat middlings. However, relative to wheat bran or wheat middlings, all feedstuffs tested were effective energy sources for juvenile black pacu and red pacu.     

Effect of 17β‐oestradiol on the sex ratio of tambaqui,Colossoma macropomum

The tambaqui Colossoma macropomum is the most important native fish in Brazilian aquaculture. Females are almost 20% heavier than males and therefore are more profitable. Based on this information, we tested four different concentrations (20, 40, 80, and 120 mg/kg diet) of oestradiol (E₂) offered during 6 weeks to tambaqui larvae and analysed their efficiency in producing female monosex batches of the species. The study was performed in two independent tests, using different genetic backgrounds (broodstocks). All treatments increased the percentage of females in the population, but only the highest E₂ dose was “free” of males in both tests. All treated groups contained intersex individuals (when sex inversion is not complete). Plasmatic E₂ concentration was similar between treated and non‐treated fish 60 days after the treatment in fish treated with 20, 40, and 80 mg E₂/kg diet. However, tambaqui treated with a 120 mg E₂/kg diet showed lower E₂ plasma concentration in comparison with the control group. Last, we chlorinated the water to ensure the environmental integrity of the study. Three days after chlorination, the water was completely free of any oestradiol residue (analysed by high‐performance liquid chromatography).