Abstract.— The effect of stocking prawns Macrobrachium rosenbergii at increasing densities in ponds with Nile tilapia Oreochromis niloticus reared at low density was evaluated. Twelve 0.01‐ha earthen ponds were stocked with 1 tilapia/m2 and 0, 2, 4, or 6 postlarvae prawn/m2. Three replicates were randomly assigned to each prawn density. Postlarval prawns were stocked a week prior to tilapia juveniles and both were harvested 175 d after the beginning of the experiment. Tilapia final average weight, survival, production, and food conversion rates did not differ significantly among treatments (P > 0.05); the averages were 531 g, 67%. 3,673 kg/ha, and 1.91, respectively. Prawn survival rates did not differ for the three stocking densities (mean 90%). However, final weight and production were significantly different (P < 0.05) as follows: 34.0, 23.0, and 14.7 g and 639, 909, and 818 kg/ha, respectively for 2. 4, and 6 prawns/m2 densities. Stocking densities up to 6 prawn/m2 did not affect tilapia production and required neither additional feeding nor significant changes in management. The polyculture system allowed an increase in total production with the same amount of supplied feed, thus improving the system sustainability.

ABSTRACT. Eyestalk ablation in lhe prawn Macrobrachillm rosellbergii (De Man) (Cruslacea, Decapoda, Palaemonidae): effecls on reproduction, epidermic pigmenlation and feeding aclivity. This study analyze the consequences ofunilateral and bilateral ablation based on ovigerous percentage, consecutive spawns, and secondary effects ofthe surgical process in the lemales of Macl'obl'achium I'osenbel'gii (De Man , 1879). Two experiments were carried out with four and seven months old females in intelmolt stage. Each experiment was comprised ofconlrol, unilateral and bilateral ablation. Eyestalk ablation was done with a bistouly with a topic hot cauterization followed by application of antibiotic pomades. The animais were maintained at constant temperature (28 ± 1,05°C) and photoperiod of 12L:12D within fibercement boxes with sandy bottom and biological filter. Females were observed once a day during foulteen weeks, registering gonadal condition, ecdysis and presence of spermatophore (mating) and spawning. Unilateral ablation technique is more etlicient due to the anticipation ofthe first spawn, repeatability between spawns, expressive rate oI' ovigerous females and survival , that favored its applicability. Bilateral eyestalk ab lation produced the mortality 01' ali the females with change in coloration and food ac tivity patterns. These results corroborate other observations on penaeid shrimps, though bi lateral ablation on some lobsters was a success. These results showing an interespecitic variation and can be used in aquaculture projects. KEY WORDS . ClUstacea, eyestalk ablation, reproduction, pigmentation, feeding activity, prawn A obtenção de pós-larvas do camarão de água doce Macrobrachium rosenbergii (De Man, 1879) é limitada pela baixa disponibilidade de fêmeas ovígeras durante os meses de inverno em regiões de clima subtropical. Quando a temperatura da água dos viveiros é inferior a 18°C, os camarões apresentam uma diminuição do crescimento somático e da atividade reprodutiva, resultando, muitas vezes, em alta mortalidade. Após a água dos viveiros ganhar calor gradativamente, o cultivo pode ser reiniciado, embora, nesta ocasião, os criadores não possuam um número suficiente de pós-larvas para o povoamento; tal fato se deve à temperatura e fotoperíodo reduzidos, responsáveis pela minimização do processo reprodutivo na maioria dos crustáceos decápodosjá estudados (STEELE et aI.

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ResumoEste estudo teve como objetivo avaliar a capacidade da ostra Crassostrea rhizophorae como filtro biológico para o tratamento de efluentes da carcinicultura e verificar a sua condição microbiológica após processo de filtração. Um total de 1080 ostras foram distribuídas em lanternas de engorda, mantidas em 12 tanques de fibra de vidro (170 L), em um delineamento inteiramente casualizado, com quatro tratamentos (sem ostras, 60, 120 e 180 ostras) e três repetições. O efluente utilizado foi proveniente do tanque de sedimentação de uma fazenda de produção de camarão. Semanalmente foram analisados: amônio (N-NH 4 + ), ortofosfato (P-PO 4 3-), total de sólidos suspensos (TSS) e clorofila-a (Cl-a) do efluente de entrada e saída. Os tratamentos com ostras apresentaram remoção semelhante (P>0,05) nos teores de Cl-a e TSS do efluente, sendo superiores (P<0,05) ao tratamento sem ostras. Não foi observada melhoria na qualidade do efluente após a passagem pelos tanques experimentais em relação ao N-NH 4 + . Em relação ao P-PO 4 3-, todos os tratamentos reduziram as concentrações desse nutriente de forma semelhante (P>0,05). Não foram observadas diferenças (P>0,05) para os valores de coliformes totais e de cobre, independentemente da densidade de estocagem. Nas amostras analisadas não foram encontrados coliformes fecais e Salmonella spp. As ostras melhoram a qualidade da água, exceto N-NH 4 + , e não apresentam contaminantes que inviabilizem seu consumo. Palavras-chave: Aquicultura integrada, Litopenaeus vannamei, microbiologia AbstractThis study aimed to evaluate the biofiltration capacity of oyster Crassostrea rhizophorae on effluents of shrimp and check their microbiological condition after filtering process. 1.080 oysters were distributed in lanterns kept 12 fiberglass tanks (170 L) in a completely randomized design with four treatments (without oysters, 60, 120 and 180 oysters) and three repetitions. It was used the effluent from the sedimentation tank. Weekly were analyzed: ammonia nitrogen (N-NH 4 + ), orthophosphate (P-PO 4 3-), total suspended solids (TSS) and chlorophyll-a (Cl-a) of the input and output effluent. The treatments

The objectives of this work were to determine the apparent digestibility coefficients (ADC) of dry matter (DM), crude protein (CP) and gross energy (GE) of coconut biscuit residues (CBR), sweet biscuits (SBR) and noodles (NR) for Nile tilapia and evaluate the performance of fingerlings fed with diets containing the residues with the highest nutritional value. In the digestibility study, 72 juveniles (with an average weight of 70.5 ± 2.7 g) were organized in a completely randomized design with three treatments and three replications (12 fish per replication). ADC was determined using an indirect method in which 0.10% chromium oxide (Cr 2 O 3 ) acted as an indicator. To evaluate performance, 225 fingerlings (with an average weight of 3.4 ± 0.5 g) were distributed across 15 tanks (150 L), creating a completely randomized design with five treatments and three replications. The test diets contained 0, 4, 8, 12 or 16% CBR. ADCDM, ADCCP and ADCGE for each of the different residues were, respectively: 85, 88 and 86% for CBR; 32, 51 and 46% for SBR; 24, 31 and 26% for NR. The inclusion of CBR significantly affected final weight of the fish, specific growth rate and protein retention rate, as well as the carcass composition values for dry matter, mineral matter, gross energy and ethereal extract. CBR presents better digestibility than the other tested residues and it can be used as a substitute for maize meal in quantities up to 11.62%, thus improving fish performance. Key words: Alternative food. Digestibility. Noodle residue. Oreochromis niloticus. Performance. ResumoObjetivou-se determinar os coeficientes de digestibilidade aparente da matéria seca (CDAMS), proteína bruta (CDAPB) e energia bruta (CDAEB) dos resíduos de biscoito de coco (RBC), biscoito doce (RBD) e macarrão (RM) para a tilápia-do-nilo e avaliar o desempenho destes alevinos alimentados com dietas contendo o resíduo com o maior valor nutritivo. No estudo de digestibilidade 72 juvenis (70,5±2,7g) foram distribuídos em um delineamento inteiramente casualizado com três tratamentos e três repetições (12 peixes por repetição). A determinação dos CDA foi realizada pelo método indireto, com a utilização de 0,10% de óxido crômico (Cr 2 O 3 ) como indicador. Para avaliação do desempenho 225 alevinos (3,4±0,5g) foram distribuídos em 15 tanques (150 L), compondo um delineamento inteiramente