Comparative effect of Pediococcus acidilactici and Lactococcus lactis on growth performance, survival and enzyme activity of western white leg shrimp (Litopenaeus vannamei)

This study was done in Shahid Kiani Marine Aquaculture Development Center, Choebde, Abadan in order to evaluate the effects of Pediiococcus acidilactici, Lactococcus lactis and vitamin C on growth performance, survival, enzymatic activities and immune responses of L. vannamei during three months. Treatments were included control group, Pediiococcus and Lactococcus treatments which fed with diet containing 1×10P9P cfu gP_1P bacteria and vitamin C. At the end of the experiment, the growth factors, immune parameters, digestive enzymes, intestinal, histology of intestine, carcasses and microbial flora (bacterial total count and lactic acid count) were evaluated. The results indicated that administration of lactobacillus had significant effects on the growth factors as the highest weight, increase specific growth rate, relative growth rate, feed conversion ratio and protein efficiency in the shrimps received pediococcus and then Lactococcus (P<0.05). The best immune function was also observed in the shrimps fed by probiotics, so that proteins and hemoglobin̛ hemolymph, phenoloxidase activity and challenged with V. parahaemolyticus showed a statistical difference comparing to the control group and the group received vitamin C (P<0.05). Some digestive enzymes, in pediococcus treatment showed a significant increase when compared to other treatments (P<0.05). Significant changes in bacterial intestinal flora were observed in probiotic groups compared with control and vitamin C groups (P < 0.05). Histological results showed the positive effects of probiotics in the gut (P < 0.05). While these supplements cannot caused to significant impacts on the shrimp carcass composition (P ˃ 0.05). As a result pediococcus group had the best performance among treatments.

Merging effects of vitamin E and C on biological factors, blood characteristics and resistance against thermal stress in rainbow trout (Onchorhyncus mykiss)

This study was conducted to assay the effects of different levels of dietary vitamins C and E on growth indices and survival and resistance against thermal stress of rainbow trout (Oncorhynchus mykiss) in pond culture of Marzan abad from December 2011 to February 2011. Seven diets were supplemented. 300 fish with the average weight of 17 g were introduced to ponds for 60 days. The results showed that the highest and the lowest weight gain were in fish fed with diet containing 50 mg/kg vitamin C and E and 0 mg/kg vitamin C and E(control) , respectively. The highest and the lowest Feed Conversion Ratio (FCR) were measured in control and diet 50 mg/kg vitamin C and E. There is a significant difference in their treatments (P<0.05). Also, the lowest and highest amount of Weight Gain (WG) were observed in (E) treatment with 165.04% and 117.5% in control, the highest and lowest Specific Growth Rate (SGR), Protein Efficiency Ratio (PER), Condition Factor (CF) was found in control and treatment 50 mg/kg vitamin C and E, respectively(P<0.05). In conclusion vitamin C and E have an important role in enhancement of growth performance and feed efficiency of rainbow trout.The highest red blood cells were found in combined treatments and which the vitamin C was added.The highest RBC were found in E treatment(1.1×104 /mm3) and the lowest one in control (P˂0.05). Counting white blood cells also confirmed highest quantity in combined treatments with (69.83×104/mm3) and the lowest one (28.83×104 /mm3) in control. In conclusion these vitamins have a significant role in blood characteristics. Meantime, the resistance against termal stress was measured at the end of 60 days by facing fishes into 5 centigrade warmer water so consentration of Cortisol and Glucose measured for this reason.The lowest cortisol amount was measured in E treatment with 188.74 ng/ml and the highest was found in control(P<0.05). There was a significant difference in blood glucose consentration of fishes in F treatment with (78.66 mg/dl) and control with 136 mg/dl as a highest one(P<0.05).

Effect of diets containing various protein and energy levels on some growth parameters, survival and the production of Astacus leptodactylus in different salinities

A factorial experiment was conducted for 60 days to determine of the response of Narrow clawed crayfish Astacus leptodactylus (average weight of 17±2.3 g) to diets containing various protein and energy levels. Nine diets containing three levels of protein (30, 35 and 40 %) and three levels of energy (300,370 and 450 kcal/100g) were formulated and prepared in this trial. Each diet also was used in two levels of salinity include 0 (fresh water) and 12 ppt(Caspian sea water). So this study was conducted with 18 treatments and triplicates random group of 5 crayfish per each 110-litre tank. Weight Gain, Feed conversion ratio (FCR), Protein Efficiency Ratio (PER), Net Protein Utilization (NPU), Daily Food Consumption (DFC), Survival (SVR) and body composition of tail-muscle meat of animal were determined. Comparing the growth parameters in response to interaction between protein, energy and salinity levels demonstrated that all growth parameters have difference between them significantly (p<0.05). Comparing between survival in fresh and Caspian Sea water showed difference significantly. Compare the body composition results indicate the greatest amount of protein absorption in diet number 2(30/370) on fresh water condition. Results from this study indicate that narrow clawed crayfish can be fed a practical diet containing 30% protein and 370 Kcal/100g on non-salinity water which is the optimize CP percentage for their producer’s profits.

A comparative study on effects of Immunoster and Immunowall as immunostimulants on some hematological, biochemical and growth indices of farmed great sturgeon juveniles (Huso huso)

Prebiotics are non-digestible food ingredients that profitably affect the host by selectively stimulating the growth and /or activation of one or a limited number of bacteria in the intestine that can enhance host health status. Immunoster (IS) and Immunowall (IW) are prebiotics and immunostimulants derived from the outer cell wall of brewers yeast, Saccharomyces cerevisiae. These substances contain MOS and �-glucans. After a four-week acclimatization period to rearing conditions and basal diet, 450 farmed great sturgeon juveniles weighing 95.58 ± 9.38 g were randomly distributed into 15 fiberglass tanks (2 × 2 × 0.53 m) in five treatments (Control, IS 1%, IW 1%, IS 3%, and IW 3%) in three replicates (completely randomized design) and kept at a density of 30 fish per tank for a period of 8 weeks at water temperature 20.55 ± 5.11ºC, dissolved oxygen 6.73 ± 0.35 mg L-1 and pH 7.92 ± 0.09. IS and IW were added at two levels of 1% and 3% to the basal diet in place of cellulose, except the control. At the beginning, in the middle and at the end of the trial, carcass analysis was done to determine the moisture, protein, fat, ash, and total carbohydrate. Also, blood samples were collected to measure hematological, biochemical and immune indices. At the end of the trial, final weight, final length, body weight increase (BWI), specific growth rate (SGR), average daily growth (ADG), protein efficiency ratio (PER), feed conversion ratio (FCR), and condition factor (CF) in fish fed on IS and IW in both levels 1% and 3% showed some differences. These differences were significant in IS 3% and IW 1% and 3% compared with the control (P<0.05). HSI showed no significant difference (P>0.05) and survival rate was 100% in all treatments. Crude protein of carcass in fish fed on IS and IW at 1% and 3% showed an increase in comparison with the control. There was significant difference between IS 3% and the control in crude protein of carcass (P<0.05). Fish fed on IS and IW at 1% and 3% showed various results in hematological and biochemical factors. It was observed significant difference in MCV between IW 1% and IS 3% compared with the control (P<0.05). Although there was an increase in values of hematocrit, hemoglobin (except IS 1%), WBC (except IW 3%), MCH, neutrophil, total protein, albumin (except IS 3%), K+, and lysozyme in fish fed on IS and IW compared with the control, it was no significant (P>0.05). The maximum count of WBC and the highest value of Ca2+ were seen in IW 1%. The maximum count of lymphocyte, the highest values of total protein, albumin and IgM were recorded in IW 3%. IS 1% had the maximum count of neutrophil and the highest concentration of lysozyme. Based on obtained results, it can be declared that IS and IW at two levels of 1% and 3% can enhance growth performance and feed efficiency and also improve some hematological, biochemical, and immune indices in farmed great sturgeon juveniles.

The study of different protein in diet and water salinity on growth and survival rate in Pacific white shrimp (Litopenaeus vannamei)

In this research reared white western shrimp (Litopenaeus vannamei ,Boone, 1931) with five diet with five different protein level contain 20%, 25%, 30%, 35% and 40% and three salinity level contain 15-17 ppt, 27-30 ppt,and 40-45 ppt researched protein percent effect and water salinity on growth, survival, feed conversion ratio, hemolymph osmolatity, hemolymph protein and corpse protein contain. In this research was 15 sorrow with 3 repeat and used from 45 tanks with 300 liters capacity. Shrimps first weight average was about 2 grams and after 60 days culture cropped down results: Shrimps biomass growth in 15-17 ppt salinity was higher than anther salinities who had meaning different with growth in 40-45 ppt salinity ( p< 0.05). But hadn’t meaning different with growth 27-30 ppt salinity. survival rate in 15-17 ppt salinity was 97.03 who was lower than another salinities. survival percent in 24-30 ppt salinity and 40-45 ppt salinity was 99.33% Highest biomass growth in different diets was in diet number 5 with 40 percent protein that it had meaning different with another diets (p<0.05) . although with informed to product expense in different diets. One kilogram shrimp product expense in different diets hadn’t meaning different (P<0.05) Survival rate in different diets hadn’t meaning different lowest feed conversion ratio was 1.67 in 15-14 salinity that hadn’t meaning different with another salinities also corpse protein quantity in different salinities and different diets hadn’t meaning different. Hemolymph Osmolality in 15-17 ppt salinity was 573.88 mOsm/kg had meaning different with hemolymph osmolality in 27-30 ppt salinity that was 650. 380 mOsm/kg and in 40-45 ppt salinity was 630.38 mOsm/kg. Hemolymph protein in 15-17 ppt salinity was 124.72 mg/ml had meaning different with hemlymph protein in 27-30 ppt salinity that was 136.52 mg/ml but hadn’t meaning different with hemolymph protein in 40-45 ppt salinity that was 128.84 mg/ml. Hemolymph protein in different diets hadn’t meaning different (p<0.05). Keywords: shrimp, Litopenaeus vannamei, protein , salinity, growth, survival rate, FCR, hemolymph osmolality, hemolymph protein.

Étude de l'impact de deux traitements, dont un sans antibiotiques, sur la santé digestive et les populations de Clostridium perfringens dans des élevages de poulets de chair.

Le problème grandissant de l’antibiorésistance remet en question plusieurs pratiques reliées à l’utilisation des antibiotiques, dont l’usage à grande échelle pour des fins de promotion de la croissance chez les animaux de consommation. Depuis 2006, le retrait des antibiotiques dans les élevages de poulets de chair en Europe a été associé à la résurgence d’entérite nécrotique, une maladie intestinale causée par la bactérie Clostridium perfringens. Alors que la pathogénie de la maladie semblait bien comprise, le retrait des antibiotiques a montré que peu de solutions de remplacement sont disponibles afin de prévenir cette maladie. Très peu d’études se sont intéressées à mieux caractériser la dynamique des populations de C. perfringens dans les élevages avicoles et l’effet que pouvait avoir le retrait des antibiotiques sur l’évolution de ces populations. La présente étude a évalué l’impact du remplacement des antibiotiques promoteurs de croissance et des anticoccidiens pendant une période de 14 mois, dans huit élevages commerciaux de poulets de chair au Québec. Un protocole d’élevage alternatif, combinant des stratégies telles que des produits à base d’huiles essentielles, des acides organiques et inorganique, une vaccination contre la coccidiose ainsi qu’une amélioration des conditions de démarrage des poussins, a été utilisé en remplacement des antimicrobiens. Les performances zootechniques, la santé digestive ainsi que l’occurrence d’entérite nécrotique pour les lots de poulets soumis au protocole d’élevage alternatif ont été comparées avec celles de lots de poulets de chair recevant une ration conventionnelle. Des analyses moléculaires basées sur la PCR et le PFGE ont été utilisées afin de documenter l’impact de la mise en place du protocole d’élevage alternatif sur les populations de C. perfringens. Les résultats obtenus montrent qu’aucune différence entre les groupes soumis aux deux types de protocoles n'est observée en ce qui a trait à la viabilité en élevage, à l'âge d'abattage et aux taux de condamnations à l'abattoir. Toutefois, les lots soumis au traitement alternatif ont eu des performances moindres pour le poids moyen à l'abattage, le gain moyen quotidien et la conversion alimentaire. Un peu plus de 27% des lots soumis au protocole alternatif ont connu un épisode d’entérite nécrotique clinique. Les analyses ont aussi montré que l’un ou l’autre des protocoles ne semble pas exercer d’influence particulière sur la dynamique temporelle des populations de C. perfringens. Pour les lots soumis au protocole d’élevage alternatif, une forte diversité génétique pour C. perfringens a été liée à un risque augmenté de vivre un épisode d’entérite nécrotique. À l’opposé, les lots alternatifs ayant vécu des épisodes récurrents de la maladie ont montré une diminution significative de la diversité génétique, ainsi qu’une augmentation marquée du nombre de souches de C. perfringens transportant plusieurs gènes de virulence. La présente étude a permis de mieux documenter, d’un point de vue économique et scientifique, la production de poulets de chair élevés sans antibiotiques ni anticoccidiens au Québec. Cette étude est la seule du genre s’étant intéressée à la caractérisation et à la comparaison dans le temps des flores de C. perfringens retrouvées dans les deux types d’élevages. Elle a révélé que la production à grande échelle de poulets de chair élevés sans antibiotiques ni anticoccidiens est possible au Québec, mais que celle-ci présente des impacts sur les performances zootechniques des oiseaux, sur leur santé digestive et sur la dynamique des populations de C. perfringens. Mots-clés : poulets de chair, antibiotiques, huiles essentielles, acides organiques, vaccination coccidiose, performances zootechniques, santé digestive, entérite nécrotique, Clostridium perfringens, dynamique populationnelle

Probiotic effect of Bacillus NL110 and Vibrio NE17 on the survival, growth performance and immune response of Macrobrachium rosenbergii (de Man)

Eight hundred and eighty-¢ve strains of bacterial isolates fromvarious samples associatedwith the natural habitat ofMacrobrachiumrosenbergii were screened for their probiotic potential. Two putative probionts namely Bacillus NL110 and Vibrio NE17 isolated from the larvae and egg samples, respectively, were selected for experimental studies and were introduced to the juveniles of M. rosenbergii (0.080 0.001g) through di¡erent modes such as through feed, water and both. The probiotic potential of the above bacteria in terms of improvements inwater quality, growth, survival, speci¢c growth rate (SGR), feed conversion ratio and immune parameters was evaluated. The treatment groups showed a signi¢cant improvement in SGR and weight gain (Po0.001). Survival among di¡erent treatment groups was better than that in the control group. There were also signi¢cant improvements in the water quality parameters such as the concentration of nitrate and ammonia in the treatment groups (Po0.05). Improvements in immune parameters such as the total haemocyte count (Po0.05), phenoloxidase activity and respiratory burst were also signi¢cant (Po0.001). It is concluded that screening of the natural micro£ora of cultured ¢sh and shell¢sh for putative probionts might yield probiotic strains of bacteria that could be utilized for an environment-friendly and organic mode of aquaculture.

Probiotic effect of Bacillus NL110 and Vibrio NE17 on the survival, growth performance and immune response of Macrobrachium rosenbergii (de Man)

Eight hundred and eighty-¢ve strains of bacterial isolates fromvarious samples associatedwith the natural habitat ofMacrobrachiumrosenbergii were screened for their probiotic potential. Two putative probionts namely Bacillus NL110 and Vibrio NE17 isolated from the larvae and egg samples, respectively, were selected for experimental studies and were introduced to the juveniles of M. rosenbergii (0.080 0.001g) through di¡erent modes such as through feed, water and both. The probiotic potential of the above bacteria in terms of improvements inwater quality, growth, survival, speci¢c growth rate (SGR), feed conversion ratio and immune parameters was evaluated. The treatment groups showed a signi¢cant improvement in SGR and weight gain (Po0.001). Survival among di¡erent treatment groups was better than that in the control group. There were also signi¢cant improvements in the water quality parameters such as the concentration of nitrate and ammonia in the treatment groups (Po0.05). Improvements in immune parameters such as the total haemocyte count (Po0.05), phenoloxidase activity and respiratory burst were also signi¢cant (Po0.001). It is concluded that screening of the natural micro£ora of cultured ¢sh and shell¢sh for putative probionts might yield probiotic strains of bacteria that could be utilized for an environment-friendly and organic mode of aquaculture

Cassava root peel as a replacement for maize in diets for growing pigs: effects on energy and nutrient digestibility, performance and carcass characteristics

Two experiments were conducted to evaluate cassava root peel (CRP) as diet component for fattening pigs. In the first experiment, ten male pigs were used to investigate the nutrient digestibility and the nutritive value of CRP as replacement for maize in the diet at 0 %, 30 %, 40 %, 50 % and 60 %, while supplementing free amino acids (fAA). During two experimental periods, faeces were quantitatively collected and analysed for chemical composition. In the second experiment, 40 pigs received the same diets as in Experiment 1, and daily feed intake and weekly weight changes were recorded. Four pigs per diet were slaughtered at 70 kg body weight to evaluate carcass traits. Digestibility of dry and organic matter, crude protein, acid detergent fibre and gross energy were depressed (p<0.05) at 60 % CRP; digestible energy content (MJ kg^(−1) DM) was 15.4 at 0 % CRP and 12.7 at 60 % CRP. In the second experiment, CRP inclusion had only a small impact on feed intake, weight gain and feed conversion ratio (p>0.05) as well as on the length of the small intestine and the Longissimus dorsi muscle area. The missing correlation of daily weight gain and feed-to-gain ratio up to a CRP inclusion of 40 % indicates that negative effects of CRP on pig growth can be avoided by respecting upper feeding limits. Hence, a combined use of CRP and fAA can reduce feeding costs for small-scale pig farmers in countries where this crop-by product is available in large amounts.

Utilisation of Giant African snail (Achatina fulica) meal as protein source by laying hens

A 12-week experiment was carried out to investigate the effects of substituting Giant African snail meal for fish meal in laying hens diet. Four diets were formulated to contain snail meal as replacement for fish meal at 0 (control), 33, 67 and 100%. A total of 120 Shaver Brown pullets aged 18 weeks were allocated to the dietary treatments in a randomised design. Each treatment consisted of three replicates and ten birds per replicate. Feed intake increased only for the 33% treatment as compared to the 67% replacement diet but did not differ from the other treatments. There were no significant treatment effects on egg performance parameters observed (egg production, egg weight, total egg mass, feed conversion ratio and percent shell). The overall feed cost of egg production reduced on the snail meal-based diets. The organoleptic evaluation of boiled eggs revealed no difference between the treatments. Based on these results it was concluded that total replacement of fish meal with cooked snail meat meal does not compromise laying performance or egg quality. The substitution is beneficial in terms of production cost reduction and the reduction of snails will have a beneficial impact especially where these snails are a serious agricultural pest. The manual collection and processing of snails can also become a source of rural income.

Deteção e Quantificação Precoce de Clostridium perfringens em Frangos de Crescimento Rápido e de Plumagem Branca na Região de Lisboa e Vale do Tejo

Clostridium perfringens é uma bactéria anaeróbia Gram positiva, formadora de esporos e produtora de toxinas capazes de causar um amplo espectro de doenças em humanos e animais. Em frangos de crescimento rápido e de plumagem branca pode causar lesões e manifestações clínicas severas como enterite necrótica aviária (ENA), associada a uma baixa eficiência produtiva e avultadas perdas económicas. Neste estudo pretendeu-se avaliar a utilização de um teste de ensaio imunocromatográfico de fluxo lateral, o Clostridium FirstTestTM, para deteção e quantificação precoce de C. perfringens em frangos de crescimento rápido e plumagem branca e posterior relação entre a presença do agente e as características dos bandos (peso médio à chegada, idade dos bandos à amostragem), fatores ambientais (densidade populacional, temperatura ambiente, humidade da cama) e os indicadores de produção (ganho médio diário, Índice de Conversão Alimentar e percentagem de mortalidade). Para tal, foram analisadas amostras fecais de trinta bandos, em dezoito explorações integradas, na Região de Lisboa e Vale do Tejo. De acordo com a classificação do Clostridium FirstTestTM, dos trinta bandos amostrados entre o décimo primeiro e o décimo quinto dia de vida, 30 % foram classificados como “Positivo” (n=9) e 10 % foram classificados como “Muito Positivo” (n=3); apresentando concentrações médias de C. perfringens de 0,1322 ng/ml e 0,3267 ng/ml, respectivamente. Os restantes bandos, 60% (n=18), foram considerados “Normal” e apresentaram concentrações médias de C. perfringens de 0,0283 ng/ml. As amostras fecais dos bandos classificados de “Positivo” e “Muito Positivo” foram posteriormente sujeitas a análise microbiológica apresentando ambos os grupos unidades formadoras de colónias (UFC), identificadas como C. perfringens. Verificou-se que não existe relação entre os resultados do Clostridium FirstTestTM e as características dos bandos, os fatores ambientais e os indicadores de produção. Verificou-se uma diminuição dos níveis de C. perfringens nos bandos sujeitos a tratamento.

Effects of cottonseed cake-based diets supplemented with blood meal, alone or with lysine, on the growth of pigs

An experiment was carried out to establish the effect on the growth of pigs of including blood meal or lysine in diets containing gossypol from cottenseed cake. Forty Landrace x Large White pigs (20 of each sex) were randomly allocated to 5 treatments of 8 pigs each in a 2x2 factorial design with two levels of lysine or two levels of blood meal in the diets plus a control diet. The pigs were fed different diets and slaughtered at 75.0+/-2.0 kg live weight for carcase analysis. Supplementing the diets with blood meal resulted in higher live weight gains (p<0.001) and improved feed conversion ratios (p<0.001) than supplementing with lysine. Pigs fed the higher level of cottonseed cake showed a significant (p<0.001) depression in live weight gain and feed conversion ratio compared to those fed a low level of the cake. There was no significant difference (p>0.05) in intake in the pigs fed diets with cottonseed cake including blood meal or synthetic lysine. The kidney and liver weights of the pigs fed the diets with a higher level of cottonseed cake were significantly greater (p<0.001) than in those fed the lower level, but when the diets containing cottonseed cake were supplemented with blood meal or lysine at the same level there was no significant difference (p>0.05) in the weights of these organs. Lysine or other factors derived from blood meal appear to be more efficient than synthetic lysine in reducing the adverse effects of gossypol.

Dietas de proteína reduzida e de diferentes digestabilidades suplementadas com aminoácidos sintéticos para frangos de corte

O conceito de proteína ideal adquiriu grande importância, devido à necessidade de maximizar o uso dos aminoácidos para a deposição de proteína corporal. O objetivo deste trabalho foi avaliar a formulação de rações com teor reduzido de PB suplementadas com aminoácidos sintéticos e de diferentes digestibilidades. Foram realizados dois experimentos (exp) utilizando frangos de corte machos das linhagens Ross (exp I) e Cobb (exp 11),no período de 3 a 6 semanas. No exp I foram testadas rações à base de milho e farelo de soja com quatro níveis de PB (20,8; 19,7; 18,6 e 17,5%). No exp 11,além dos tratamentos com os mesmos níveis de PB do exp I e digestibilidade padrão (DP), compostos principalmente por milho e farelo de soja, também foram testados dois tratamentos com dietas contendo 20,8 e 17,5% de PB e alta digestibilidade (AD), à base de milho, farelo de soja, amido de milho e proteína isolada de soja. Nos dois experimentos o ganho de peso, a conversão alimentar e o rendimento de cortes nobres foram negativamente afetados pela redução da PB dietética (P<0,05). Entretanto, as respostas de digestibilidade da matéria seca e digestibilidade da matéria orgânica, a retenção relativa de PB e a energia metabolizável aparente corrigida para nitrogênio foram superiores nas aves alimentadas com as dietas de baixos níveis de PB (P<0,05), mas não suficientes para compensar as perdas no desempenho. Não houve efeito da dieta AD sobre as respostas avaliadas, talvez em função das características físicas dos ingredientes utilizados.

Effect of poultry viscera meal inclusion in broiler diets in different rearing periods on performance, carcass and parts yields

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Digestibility and performance of pacu (Piaractus mesopotamicus) juveniles - fed diets containing different protein, lipid and carbohydrate levels

Due to lack of information on the use of non-protein energy sources in diets for pacu (Piaractus mesopotamicus), a 2 x 2 x 3 factorial experiment was conducted to evaluate the performance and digestibility of 12 diets containing approximately two crude protein (CP; 220 and 250 g kg(-1)), two lipid (40 and 80 g kg(-1)) and three carbohydrate levels (410, 460 and 500 g kg(-1)). The pacu juveniles-fed diets containing 220 g kg(-1) CP did not respond (P > 0.05) to increased dietary lipid and carbohydrate levels, but the fish-fed diets containing 250 g kg(-1) CP showed a better feed conversion ratio. There were interactions in weight gain (WG), specific growth rate (SGR), crude protein intake (CPI) and feed conversion rate (FCR) dependent on dietary carbohydrate and lipid levels, showing positive effects of increasing carbohydrate levels only for fish-fed diets containing 80 g kg(-1) lipid level. However, when the diets contained 40 g kg(-1) lipid, the best energy productive value (EPV) results were obtained at 460 g kg(-1) carbohydrate. A higher usage of lipids (80 g kg(-1)) reduced CPI and was detrimental to protein [apparent digestibility coefficient (ADC)(CP)] and energy (ADC(GE)), but did not affect growth. The ADC(GE) improved proportionally as dietary carbohydrate levels increased (P < 0.05), increasing the concentration of digestible energy. In addition, the WG, CPI, ADC(GE) results showed best use of the energy from carbohydrates when dietary protein level was 250 g kg(-1) CP. The utilization of 250 g kg(-1) CP in feeds for juvenile pacu for optimal growth is suggested. Therefore, the optimum dietary lipid and carbohydrate levels depend on their combinations. It can be stated that pacu uses carbohydrates as effectively as lipids in the maximization of protein usage, as long as it is not lower than 250 g kg(-1) CP or approximately 230 g kg(-1) digestible protein.