Effect of feeding level on feed losses and feed utilization of soya and fish meal diets in Colossoma macropomum (Cuvier)

Juvenile, 1-g Colossoma macropomum (Cuvier) were fed two different diets: one with fish meal and another with soya meal as the main dietary protein source. Both diets were provided at ad libitum feeding level, and at two restricted feeding levels of ～ 80% and 60% of the ad libitum level. The experiment was performed in 30 aquaria, each stocked with 12 fish. For each treatment (two diets X three feeding levels), there were five replicates. Fish were fed three times daily at 0900, 1300 and 1700 h. At sampling days (days 14, 29, 44) in each aquarium in one of these feedings, chromic-oxide-marked feed was used. Shortly after the last meal, fish were weighed and four fish were taken from each aquarium for determination of the chromic oxide content in their digestive tract. Fish fed the fish meal diet attained a higher weight but had a lower body protein content. At the ad libitum feeding level, feed intake of the fish meal diet was higher, but feed and protein utilization efficiency were lower than with the soya diet. However, statistical analysis of the data of both the ad libitum and the two restricted feeding levels revealed that the reduced voluntary feed intake of the soya diet was the cause of its better utilization with ad libitum feeding. There is no evidence that soya protein is more freely available than fish meal protein. The chromic oxide data showed that 15 min after feeding, all of the feed (99.8%) could be traced back in fish fed the lowest feeding level, while at the ad libitum feeding level the recovery was only 72%. These data confirmed the hypothesis that at high feeding levels, considerable amounts of feed remain uneaten. Feed losses were not significantly different between the two diets. The chromic oxide recovery data of the 0900 h and 1300 h feedings showed that the feed passage rate in the digestive tract was similar for the three different feeding levels. Due to the high feed losses at high feeding levels, the relation between feed ration and feed utilization is determined mainly by the percentage of feed losses at the different feed rations.     

Growth performance of Colossoma macropomum(Cuvier) juveniles at different feed rations

Abstract Growth performance, feed utilization and changes in body composition of Colossoma macropomum (Cuvier) juveniles — in the weight range 2 to 200g — fed an artificial high protein diet, have been analysed against feed ration and fish weight. A polynomic equation is developed which permits prediction of growth and radon parameters in this weight range. The results are compared with the values of other cultured common freshwater fish species. Colossoma macropomum must be considered a very fast grower with good feed utilization.     

Growth and body composition of juvenile Colossoma macropomum Cuvier 1818 (Characoidei) feeding on artificial diets

Juvenile Colossoma macropomum were fed for 56 days with six pelleted feeds which contained fish meal and blood meal as sources of animal protein in varying proportions. Blood meal can be incorporated in a diet together with fish meal but it was inadequate as the only source of animal protein for young C. macropomum. Growth rates from 1.1 to 2.5% dry weight/day were proportional to dietary crude protein levels (25–37%) while dry matter content of whole fish bodies (35-26%) was inversely proportional to growth rate. Body composition on a dry matter basis shows highest protein (53%) and lowest fat level (26%) for the fastest growing fish.     

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.     

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.     

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.     

Effect of dietary lipid level on protein utilization and the size and proximate composition of body compartments of Colossoma macropomum (Cuvier)

Juvenile Colossoma macropomum were fed ad libitum diets containing either 30% or 40% protein, while the dietary lipid level varied between 5% and 20%. Growth and protein utilization efficiency increased with the dietary lipid level. However, the economic feasibility of the addition of extra dietary lipid to C. macropomum diets is questionable, as for every extra gram of protein deposition it was necessary to replace 20–25 g of dietary carbohydrates by lipids. Moreover, increased dietary lipid levels resulted in increased lipid deposition. In C. macropomum, feed uptake was regulated by the dietary protein level and unaffected by the dietary lipid level. Dissection of the body into head, viscera and trunk revealed that 45–48% of the body lipids were stored in the trunk, independent of diet composition. A positive relation between dietary and body protein level was confirmed in this experiment. However, the dissection of the body revealed that the body protein concentrations in head + viscera and trunk are not changed significantly by the dietary protein level. The higher protein contents offish fed higher-protein diets are due to an increase in the relative weight of the trunk (muscle) to the total body weight.     

Impact of pond management on tambaqui, Colossoma macropomum (Cuvier), production during growth-out phase

This study evaluated the impact of pond management on tambaqui, Colossoma macropomum (Cuvier), rearing during the growout phase. Juvenile tambaqui were stocked in ponds with three different management regimes: (1) natural ponds (Nat); (2) limed ponds (Lim); and (3) limed and bimonthly fertilized ponds (LimFer). The experiment lasted 210 days and the growth parameters were evaluated monthly. Water quality and effluent measurements were performed every 15 days and at the end of the experiment yield parameters were obtained. There was no difference in weight and length among treatments. Stomach contents and zooplankton availability were not influenced by pond management, but the rearing period had an influence on them. Food conversion rate (FCR) was better in fish from the Lim treatment than in fish from the Nat treatment. The pH, hardness and alkalinity values were significantly higher in the Lim and LimFer ponds, where the liming procedure was performed. The effluent analysis showed a more potentially impacting effluent in the LimFer treatment, where phosphorus and orthophosphate concentrations showed values significantly higher than those in Lim and Nat ponds. The results show that the Lim treatment is the best approach, as in this treatment fish achieve market size, better FCR, yield and have a reduced environmental impact.     

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.     

Observations on induced breeding of the Amazonian fish tambaqui, Colossoma macropomum (Cuvier) using CPE and HCG treatments

Trials on induced breeding of the native Amazonian fish tambaqui, Colossoma macropomum (Cuvier), using CPE and HCG treatments, were carried out during 1992-93 at the Fish Culture Station in Natal, Brazil. Final maturation, ovulation and spermiation of tambaqui broodstock, reared in earthen ponds, were induced by injecting heteroplastic carp pituitary gland extracts (CPE) and human chorionic gonadotrophin (HCG) separately. The female spawners received double injections and the males received a single dose. Females were tranquillized using quinaldine and their genital openings were sutured before the resolving injection was administered. Latent period between the resolving injection and ovulation varied from 6 to 11 h according to the prevailing water temperature. Milt was obtained by extrusion. Stripping and dry fertilization of the eggs produced viable larvae. Relative fecundity was estimated at 140 000 eggs kg^-1. Mean fertilization and hatching rates varied from 50% to 70% and from 60% to 80%, respectively.     

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.     

Population dynamics of tambaqui, Colossoma macropomum Cuvier, in the Lower Amazon, Brazil

Fishery statistics and length data series for Colossoma macropomum Cuvier obtained during 1992 and 1993 in the Lower Amazon, Brazil were used to describe the fishery and to estimate growth and mortality rates. Mean population parameters were L _∞ = 119.85 cm (total length), W _∞ = 33.4 kg, K = 0.228 year^–1, C = 0.505, Winter Point = July, M = 0.445 year^–1, F = 0.94 year^–1 and L_c = 28.29 cm. Yield-per-recruit analysis showed that an excessive fishing effort and principally a very low length at first capture lead to an increase in overfishing in the region. Corrective measures are recommended.     

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.     

Growth, digestive enzyme activities and hepatic glycogen levels in juvenile Colossoma macropomum Cuvier from South America during feeding, starvation and refeeding

Abstract. Feeding trials with juvenile Colossoma macropomum Cuvier (approximately 40g) were carried out to study their protein requirements and their efficiency in metabolizing vegetable protein. Two groups of diets were used. In one group, the crude protein consisted exclusively of fish protein concentrate. In the second group the protein consisted of a mixture (55:45) of vegetable and animal protein without fish meal. In each group 30 and 50% protein levels were used. The highest weight increase (1·64%/day) and the lowest feeding rate were obtained with the 50% protein fish meal free diet. During the trial all fish accumulated visceral fat while body protein content decreased and dry matter increased. There was a high correlation between liver weight and liver glycogen. The highest amounts of liver glycogen were induced by diets containing fish meal and/or low protein content. In contrast lo visceral fat deposits, accumulated liver glycogen was of less significance for surviving starvation periods. The activity of digestive enzymes depends on both stomach and gut fullness. Trypsin activity, contrary to pepsin, was correlated with diet protein content, a-amylase activity was not correlated with diet composition.     

Digestible protein requirements and muscle growth in juvenile tambaqui (Colossoma macropomum)

Several investigations have been carried out to improve the productivity of tambaqui, an economically important fish species in Brazil and other Latin American countries. This study determined the digestible protein (DP) requirements in juvenile tambaqui by assessing their productive performance and nutritional efficiency. It also evaluated the effects of different dietary DP levels on the morphology and cellularity of skeletal fast muscle fibres. The 1750 tambaqui tested (6.53 ± 0.43 g body weight, 7.58 ± 0.18 cm length) were randomly distributed into 35 tanks. Fish were fed one of the seven isocaloric diets, which contained 140, 170, 200, 230, 260, 290 or 320 g/kg DP. The DP requirement, calculated by segmented (broken line) regression of weight gain data, was 290 g/kg. An increase in diet DP to 290 g/kg significantly improved final weight, weight gain, feed intake, specific growth rate and crude protein gain, and changed fibre diameter in deep muscle. Muscle fibres were randomly distributed into a mosaic pattern, characterized by fibres with different diameters. Treatments with 290 and 320 g/kg DP increased the frequency of large‐diameter fibres (>50 µm), indicating hypertrophic growth of skeletal muscle during the juvenile phase, which occurred in conjunction with hyperplasia.     

Genetic parameters for loin eye area and other body traits of an important Neotropical aquaculture species,Colossoma macropomum (Cuvier, 1818)

Estimating components of variance and genetic parameters of economically relevant traits is the first step towards planning a breeding program for aquaculture species. This study estimated the (co)variance components for growth rate and other body traits and then determined a multiple regression equation to assess the loin eye area (LEA) from morphometric traits of the Neotropical aquaculture species Colossoma macropomum. Estimation of variance components was performed using derivative‐free restricted maximum likelihood estimation using the MTDFREML package. Six predictive variables were tested to estimate the coefficient of regression equation and to select the most suitable model for predicting LEA. The estimated genetic parameter for body weight showed moderate‐to‐high heritability estimates of 0.26 (0.01) and 0.49 (0.01) at 221 and 623 days respectively. The genetic correlation (r_g) estimates between body size measurements were positive and ranged from low to high at both ages. The heritability for LEA in this assessment was 0.39 (0.03). The genetic and phenotypic correlations between LEA and the other body measurements ranged from 0.16 to 0.94 and 0.75 and 0.90 respectively. The outcomes of this study can contribute to the development of a genetics‐based breeding program that will improve (tambaqui) productivity and carcass quality.     

Effects of aflatoxin B 1 on performance and health of tambaqui fingerlings ( Colossoma macropomum )

The detection of mycotoxins in feeds and their ingredients in aquaculture gained prominence due to losses caused in production and animal health, mainly the occurrence of aflatoxin (AFB1). The aim of this study was to evaluate the effects of AFB1 on the performance of tambaqui fingerlings (Colossoma macropomum). Four hundred tambaqui were used. Four different treatments were evaluated: treatment T1, considered as the control treatment (CT) with 3.84 μg kg−1; treatment T2, treatment T3 and treatment T4 with 500, 1000 and 2000 μg kg−1 of AFB1, respectively. The AFB1 of the samples (muscle, liver and kidney) was detected by high-pressure liquid chromatography. Four fingerlings from each treatment for histological analysis were examined. Moreover, the performance parameters (weight gain, feed conversion and feed intake) were studied. The levels of toxins used in T2, T3 and T4 represent a reduction in the growth of 14%, 35% and 45%, respectively. The T3 and T4 showed the lowest weight gain (78%) and the worst feed conversion. Aflatoxin B1 in muscle (3.28 μg kg−1) and kidneys (8.8 μg kg−1) in the T3, as well as liver (4.4 μg kg−1) and kidney (4.08 μg kg−1) in T4, was detected. Histopathological changes in liver and kidney tissues of fingerlings were more pronounced in T3 and T4. Fingerlings that consume feed contaminated with AFB1 in concentrations higher than 500 μg kg−1 present decreases in growth, reduction in weight gain and feed intake with increased feed conversion. The consumption of feed contaminated with 1000 and 2000 μg kg−1 of AFB1 caused severe deterioration in the hepatic and renal tissues.