ABSTRACT. The aim of this study was to determine the apparent digestibility coefficients and digestible values of crude protein, ethereal extract, gross energy and dry matter of mulberry leaf meal (MLM) (Morus alba L.) as Nile tilapia (Oreochromis niloticus) feed. A total of 135 Nile tilapia juveniles were used, and the indirect methodology (Cr2O3) was applied for digestibility determinations. Mulberry leave meal presented good apparent digestible coefficients of protein, ethereal extract and energy with respective values of 0.94, 0.58 and 0.39. The mulberry leave meal thus comprises adequate digestible protein and digestible energy values, similar or better than other leafy foods, presenting potential for inclusion in Nile tilapia diets.

Abstract The aim of this study was to evaluate the effect of different crude glycerin levels in the diet of Nile tilapia fingerlings (mean initial weight 0.32 ± 0.06 g, n = 450) on growth performance parameters, whole-body composition, blood glucose and liver morphology. Crude glycerin was tested at six different levels (0, 4, 8, 12, 16, and 20%) in diets containing 30% digestible protein and 3,000 kcal kg-1 digestible energy. After 37 days of feeding, the inclusion of crude glycerin resulted in positive effects on final weight, visceral fat, weight gain, feed conversion, specific growth rate and feed intake. The different treatments did not influence fillet yield, glycemia, survival and hepatosomatic index, but intermediate levels of inclusion decreased the area of hepatocytes. Regarding fish body composition, significant differences were found in moisture and ash contents, with no changes in crude protein and total lipid. The inclusion of crude glycerin in the Nile tilapia diet improves growth performance without negatively affecting survival rate and glycemia of fingerlings.

ABSTRACT The effects of a diet supplemented with 5% marine fish oil, 5% refined palm oil, 5% soybean oil, and a combination of the three on reproductive parameters of females Rhamdia quelen was investigated. Spawning was artificially induced to evaluate rates of fertilization, hatching and larvae normality. Fatty acid profiles of the diets, ovaries and oocytes were determined. A higher spawning rate (%) was observed for diets containing fish oil (78.65 ± 3.60) and palm oil (77.15 ± 3.97), followed by oil mix (65.46 ± 4.57). The diet containing soybean oil was associated with significantly lower fertilization (60.14 ± 5.66; P < 0.05) than the palm and fish oil diets. Lower fertilization may be explained by a high level of n-6 fatty acids in the diet, which possibly accelerate the oocyte maturation. Satisfactory fecundity (P > 0.05) were observed for all tested diets, whit 289.77 ± 23.90 (palm oil) until 323.31 ± 38.45 oocytes g-1 body weight (fish oil). The treatments were not shown to influence oocyte size, larval size or rate of larva deformity. Oocyte fatty acid composition was like that of gonads. Docosahexaenoic (DHA; C22:6 n-3) fatty acid was preferentially deposited in ovaries and oocytes. Ratios of n3/n6, DHA/EPA, EPA/ARA, did not affect the reproductive performance of females. Therefore, regarding female reproductive performance, the vegetable lipid sources tested are suitable for being used in R. quelen diet, and palm oil, in particular, is considered an excellent alternative to fish oil.

Abstract: The aim of this study was to evaluate the production performance of Nile tilapia post-larvae and fingerlings fed with increasing levels of alcoholic extract of propolis into diets. In Experiment 1, 1800 post-larvae were distributed in 30 tanks, in a completely randomized design with five treatments composed by the inclusion of 0, 1, 2, 3 and 4 g of dry propolis/kg of feed, and six replicates. In experiment 2, 1600 fingerlings were distributed in the same system and designed as experiment 1. No significant effect was observed between treatments, for final weight, total and standard length, survival, and intestinal villus height. However, the propolis extract inclusion of 1 g/kg in Nile tilapia post-larvae and fingerlings’ feed resulted in a better body condition factor and higher body protein deposition (p<0.05). The condition factor is an estimate for the future growth of the animals, possibly the fish treated with propolis extract will present better growth, survival and greater reproductive potential rates. The results of the present study demonstrate that alcoholic extract of propolis improves the nutritional condition of Nile tilapia post-larvae and fingerlings, potentially leading to increased productivity in subsequent stages, as well as leading to improvement in fingerlings muscle deposition.

RESUMO. Objetivou-se determinar a exigência de proteína digestível (PD) para a tilápia do Nilo, alimentada com dietas à base de farelo de soja e milho. Duzentos juvenis de tilápia do Nilo (32,80 ± 0,39 g), sexualmente revertidos, foram utilizados por um período experimental de 100 dias. Os animais foram distribuídos em 20 caixas de 1000L-1 em delineamento aleatório com cinco tratamentos e quatro repetições. As caixas eram ligadas a um sistema de recirculação de água. Foram testadas cinco dietas isoenergéticas com diferentes níveis de PD: 20, 25, 30, 35 e 40%. Ao final do período experimental, foram avaliados os dados de desempenho zootécnico. Um efeito quadrático (p < 0,05) foi mostrado aos parâmetros de peso final, ganho em peso, comprimento final, rendimento de filé e de gordura visceral com os melhores pontos que variaram de 28,3 a 29,9% de PD. A maior área dos hepatócitos foi encontrada para os níveis mais baixos de PD na dieta (20 e 25%), em comparação com os outros níveis, que foram semelhantes. Assim, pode-se afirmar que a tilápia do Nilo tem desempenho adequado para o consumo de dietas baseadas em farelo de soja e milho e o nível recomendado é de 28,3% PD nestas condições.

ABSTRACT. The objective was to determine the requirement of digestible protein (DP) for Nile tilapia fed with diets based on soybean meal and corn. Two hundred Nile tilapia juveniles, sexually reversed, were used for a trial period of 100 days. The animals were distributed in 20 boxes of 1000 L-1 in a random design with five treatments and four replications, the boxes were connected to a water recirculation system. Five isoenergetic diets were tested with different levels of digestible protein (DP): 20, 25, 30, 35 and 40%. At the end of the experimental period were evaluated the zootechnical performance data. A quadratic effect (p < 0.05) was shown to parameters of final weight, weight gain, final length, fillet yield and visceral fat with the best points that ranged from 28.3 to 29.9% of DP. The largest area of hepatocytes was found to the lowest levels of DP in the diet (20 and 25%) compared to the other levels, which were similar. Thus, Nile tilapia has adequate performance for the consumption of diets based on soybean and corn meal and the recommended level is 28.3% of PD in these conditions.

ABSTRACT This experiment was conducted in outdoor tanks to evaluate the effect of inclusion of ractopamine at increasing levels (0, 4, 8, 12, and 16 mg kg−1) as additive in Nile tilapia (Oreochromis niloticus) diet in the final grow-out period (750-920 g) during 31 days. Therefore, 400 fish were housed into 20 experimental tanks, in a completely randomized design with five treatments and four replications. Growth performance, body yield, and chemical composition of fish muscle and organs were evaluated. Fish fed diets containing up to 16 mg kg−1 of ractopamine for 31 days did not improve growth or performance parameters. However, lipid percentage of abdominal muscle was different in fish fed ractopamine, reaching the lowest level of 199.3 g kg−1 of ether extract at 8 mg kg−1 treatment. Other body chemical composition parameters did not differ between animals treated or not treated. Feeding ractopamine up to 31 days has limited effect on body composition in Nile tilapia (~900 g), without any changes in growth parameters. This is a lower metabolic response in this species when compared with mammals and other terrestrial animals.

The present experiment was carried out to evaluate the growth and reproductive parameters of Rhamdia quelen females fed with pelleted ration containing different levels of digestible energy, and to evaluate the vigor of their offspring. The breeders were placed in tanks under conditions of photoperiod and natural temperature. The fishes were fed for 255 days with isoproteic rations pelleted containing 35% of crude protein (CP) and five levels of the digestible energy (DE) (2700, 2950, 3200, 3450, 3700 kcal kg-1). The fishes were distributed in a randomized experimental design compounded by five treatments and three repetitions. A 16-m² tank containing six females and three males was considered as one experimental unit. The weight and weight gain was evaluated. During the reproductive season the females were induced to breeding by hormonal manipulation and were evaluated the percentage of spawning females, the total fecundity, relative fecundity (number of oocytes per gram of spawning females), the fertilization ratio, the time to hatching and the vigor of larvae. The growth and reproductive parameters were not influenced (P > 0.05) by the increasing levels of digestible energy of the rations. The feeding of R. quelen females in breeding fit can be carried out with 2700 kcal kg-1 pelletized ration based on vegetal ingredients, without damage to reproductive performance.

El presente estudio se efectuó para evaluar el crecimiento y reproducción de hembras de bagre (Rhamdia quelen) alimentadas con dietas con diferente contenido de energía, elaboradas con ingredientes vegetales. Además, se evaluó el vigor de las crías. Los reproductores se colocaron en estanques en condiciones de fotoperiodo y temperatura ambiente. Los peces fueron alimentados durante 255 días con raciones isoproteicas que contenían 35% de proteína cruda (PC) y 2700, 2950, 3200, 3450 y 3700 kcal de energía digestible (ED) kg-1. Los peces se distribuyeron en un diseño completamente al azar con cinco tratamientos y tres repeticiones. Para el experimento se emplearon estanques de ~16 m² con seis hembras y tres machos. Se evaluó el peso medio final y la ganancia media de peso. Durante el período reproductivo se evaluó el porcentaje de hembras que desovan, número total de ovocitos, número de ovocitos por gramo en hembras reproductoras, tasa de fertilización, tiempo necesario para que la eclosión de los huevos y tiempo de supervivencia de las larvas. El crecimiento y los parámetros reproductivos no fueron afectados (P > 0,05) por el aumento de los niveles de energía de las raciones. Se concluye que para obtener mejor reproducción de bagre (R. quelen) se recomienda emplear raciones peletizadas de 2700 kcal kg-1.

This study evaluated the effect of feed supplementation (at doses of 0, 50, 100, 150, and 200 mg/kg) with SALUTO®, a microencapsulated blend of essential oils including carvacrol, cinnamaldehyde, 1,8-cineol, and pepper oleoresin, in Nile tilapia (Oreochromis niloticus) broodstock on reproductive and growth parameters during the initial phase of rearing. The growth parameters, somatic indexes and gonadal and hepatic parameters were analyzed. Quantitative parameters of growth, ovary fat and crude protein were not affected by supplementation of the additive. However, an increase in crude protein in the female liver was observed in correlation with increased essential oil levels. The female hepatosomatic index was also correlated with supplementation of essential oils. Feeding Nile tilapia broodstock diets containing an essential oil compound (SALUTO®) affects only the females, promoting an increase in liver protein inclusion and hepatosomatic index without impairing performance.

O aumento na produção mundial de biodiesel está gerando um excesso de glicerol, sem destinação definida. Uma alternativa para superar este problema é seu uso como fonte de energia na alimentação animal. No Brasil, o pacu (Piaractus mesopotamicus) é uma das espécies de peixes nativas mais cultivadas, enquanto que o jundiá (Rhamdia quelen) é apropriado para a produção na região subtropical. Considerando a falta de conhecimento sobre a utilização do glicerol bruto em rações para espécies de peixes Neotropicais, determinaram-se os coeficientes de digestibilidade aparente (CDAs) para a energia do glicerol bruto em P. mesopotamicus e R. quelen. A digestibilidade e o conteúdo de energia digestível do glicerol bruto podem ser considerados excelentes, mesmo quando comparados à energia de ingredientes comuns, como o milho e o trigo, apresentando para energia CDA de 0,97 e 0,89, e 15,2 e 13,95MJ kg-1 de energia digestível para o pacu e o jundiá, respectivamente. Por fim, o glicerol bruto é um ingrediente energético com bom potencial para dietas de peixes nativos do Brasil.

The increase in global biodiesel production is originating a glycerol surplus, which has no defined destination. An alternative to overcome this problem is its use as energy source in animal feeding. In Brazil, Pacu (Piaractus mesopotamicus) is one of the most farmed native fish species, whereas Silver catfish (Rhamdia quelen) is suitable for production in subtropical region. Considering little knowledge about crude glycerol utilization in feeds for Neotropical fish species, it was evaluated the apparent digestibility coefficients (ADCs) for energy of crude glycerol for P. mesopotamicus and R. quelen. The digestibility and digestible energy content of crude glycerol can be considered excellent even when compared to energy of common ingredients such as maize and wheat, presenting 0.97 and 0.89 of energy ADCs, and 15.2 and 13.95MJ kg-1 of digestible energy for Pacu and Silver catfish, respectively. In conclusion, crude glycerol is an energetic ingredient with good potential in Brazilian native fish diets.

A utilização de óleos essenciais e extratos herbais como aditivos para alimentação dos peixes têm demonstrado grande potencial, necessitando ainda que ensaios a campo sejam realizados para se determinar a utilização definitiva destes compostos. Com o objetivo de avaliar o desempenho zootécnico de alevinos de tilápia do Nilo Oreochromis niloticus alimentados com ração contendo diferentes níveis de óleos essenciais, realizou-se um experimento em delineamento inteiramente casualizado com 5 tratamentos e 4 repetições: 0.000; 0,005; 0,010; 0,015 e 0,020% de um aditivo comercial microencapsulado à base de óleos essenciais adicionados na ração. Tanques-rede com volume de 1m³ foram utilizados como unidades experimentais com uma densidade de estocagem de 50 alevinos.m-3. Ao final de 69 dias de cultivo não se verificou uma relação entre os diferentes níveis de óleos essenciais e os parâmetros de sobrevivência (%), ganho em peso (g), taxa de crescimento (g/dia) e conversão alimentar aparente (CAA). Por outro lado verificou-se uma relação quadrática para o conteúdo de proteína corporal, com ponto de máximo estimado em 0,0097% de inclusão. Sendo assim, conclui-se que os níveis do aditivo utilizados no presente estudo não forneceram evidências do efeito positivo dos óleos essenciais sobre o desempenho de alevinos de tilápia do Nilo, principalmente como promotor de crescimento.

The use of herbal extracts and essential oils as additives for fish feed have shown great potential, still requiring that the field trials are performed to determine the final use of these compounds. Aiming to evaluate the growth performance of Nile tilapia fingerlings Oreochromis niloticus fed with different levels essential oils, an experiment was conducted in a completely randomized design with 5 treatments and 4 replicates: 0,000, 0,005, 0,010, 0,015 and 0,020% of a commercial blend microencapsulate based on essential oils in the diet. Net tanks with volume of 1m³ were used as experimental units with a stocking density of 50 fingerling m³. At the end of 69 days of culture there was no relation between levels of essential oils and the parameters of survival (%), weight gain (g), growth rate (g/day) and feed conversion. On the other hand there was a quadratic relationship of body protein content for different levels of the commercial blend microencapsulate in the diet with the maximum point estimated at 0,0097% inclusion. Therefore, it is concluded that the levels of essential oils used in this study did not provide evidence of the positive effect on the performance of Nile tilapia fingerlings, mainly as a growth promoter.

This study was carried out to evaluate the influence of different levels of digestible energy and digestible protein in diets of Nile tilapia (Oreochromis niloticus) broodstock on offspring growth during sex reversal stage. A total of 2,700 post-larvae (8.2±0.001 mg) derived from breeders fed nine diets with distinct levels of digestible protein (28, 34 and 40% DP) and digestible energy (2,800; 3,400; and 4,000 kcal DE.kg-1) were stored in twenty-seven 70 L tanks. After 30 days of growth, their average final weight (AFW, g), average weight gain (AWG, g), final standard length (SL, cm), condition factor (CF), specific growth rate (SGR, %/day), stock uniformity (UNI, %), survival (SUR, %) and sex reversal rate (SRR, %) were measured. Although female nutrition is thought to influence the performance or quality of progeny during early life stages, no influence of diets supplied to broodstock was detected on any parameter. Nonetheless, the offspring presented commercially satisfactory growth rates. Thus, diets containing 28% of digestible protein and 2,800 kcal of digestible energy.kg of diet-1 can be used to feed Nile tilapia broodstock without jeopardizing offspring performance during the sex reversal phase.

O pacamã (Lophiosilurus alexandri) é uma espécie de peixe com hábito alimentar carnívoro, apropriada para o cultivo, porém, ainda pouco estudada. O objetivo deste estudo foi determinar a exigência de proteína bruta (PB) do pacamã, L. alexandri, na fase juvenil. O experimento foi conduzido por um período de 45 dias utilizando um delineamento inteiramente casualizado, com cinco tratamentos (dieta contendo 36,2; 38,2; 42,0; 44,4 e 48,8% de PB) e quatro repetições cada, onde 100 juvenis (5,19 ± 0,01g) foram distribuídos em 20 caixas com volume útil de 36 L, sendo considerada como unidade experimental uma caixa com cinco juvenis. Foram avaliados os parâmetros de peso final, percentagem de ganho de peso, taxa de crescimento específico, sobrevivência, índice hepatossomático, rendimento de carcaça com e sem cabeça, comprimento total, comprimento da cabeça, largura e altura. Pela análise de regressão foi verificada uma redução linear (P<0.01) nos parâmetros de desempenho em função do nível protéico da ração. Quando comparados pelo teste de Tukey, o melhor resultado (P<0.01) foi obtido com 36,2% de PB. Não houve influência dos tratamentos nos outros parâmetros avaliados (p>0,05). Deste modo, recomenda-se a utilização de rações contendo entre 36,2% de proteína bruta para juvenis de pacamã (L. alexandri).

Pacamã (Lophiosilurus alexandri) is a species of carnivorous fish, suitable for farming, but little studied. The aim of this study was to determinate crude protein (CP) requirement to pacamã, L. alexandri, in juvenile phase, an experiment was conducted during 45 days in a completely randomized design, with five treatments (36.2, 38.2, 42.0, 44.4, and 48.8% CP of diet) and four replications, where a hundred juvenile fishes (5.19 ± 0.01 g) were distributed in twenty 36 L aquaria. Each aquarium with five juveniles was considered an experimental unit. The parameters evaluated were final weight, percentage weight gain, specific growth rate, survival rate, hepatosomatic index, carcass yield with and without head, total length, head length, width, and height. By the regression analysis was verify a (P<0.01) linear decrease to performance parameters in function to ration protein growth, however to Tukey test the best (P<0.01) result was obtained with 36.2% of CP. There was no influence of treatments on the other evaluated parameters (p>0.05). Thus, it is recommended to use feed containing 36.2% of crude protein to pacamã (L. alexandri) juveniles.

A reversão sexual é uma das fases mais importantes para a criação comercial da tilápia do Nilo em função dos problemas advindos com a reprodução precoce dessa espécie em tanques de cultivo. Objetivou-se determinar o efeito da frequência de arraçoamento sobre o crescimento e a percentagem sexual da tilápia do Nilo (Oreochromis niloticus) durante a fase de reversão sexual. Quinhentas pós-larvas de tilápia do Nilo foram utilizadas e estocadas em vinte e cinco aquários plásticos (36L) em um delineamento experimental totalmente casualizado com cinco tratamentos e cinco repetições. Os tratamentos foram: uma alimentação (10h), duas alimentações (09h e 17h), três alimentações (09h; 13h e 17h), quatro alimentações (07h; 10h; 13h e 17h) e cinco alimentações (07h; 09h; 11h; 15h e 17h). A frequência de arraçoamento influencia a percentagem de machos, na qual os tratamentos com quatro e cinco arraçoamento proporcionam valores semelhantes entre si, porém superiores (P<0,01) aos demais tratamentos. Recomendam-se pelo menos quatro alimentações diárias para proporcionar lotes de alevinos de tilápia do Nilo com índice de reversão sexual adequado para a criação.

The sex reversal is one of the most important stages for the commercial breeding of Nile tilapia in relation to the problems arising from early breeding of this species in cultivation tanks. The objective was to determine the effect of feeding frequency on growth and sex ratio of Nile tilapia (Oreochromis niloticus) during the sex reversal phase. Five hundred Nile tilapia fry were used and stocked in twenty-five plastic aquaria (36L) in a completely randomized design with five treatments and five replicates. The treatments were: one feeding (10h), two feeding (09h and 17h), three feeding (09h; 13h and 17h), four feeding (07h; 10h; 13h and 17h), and five feeding (07h; 09h; 11h; 15h and 17h). The feeding frequency affected sex ratio of male fingerlings, where the treatments with four and five feedings provided similar values, but higher (P<0.01) than other treatments. It is recommended feeding frequency at least four times a day to provide lots with suitable index of sex reversal for cultivation.

Avaliou-se a inclusão de milheto em rações com 30% de proteína digestível e 3.000 kcal de energia digestível/kg para alevinos de tilápia-do-nilo. O experimento foi realizado em delineamento inteiramente casualizado, com cinco rações (0,00; 7,00; 14,00; 21,00 e 28,00% de inclusão de milheto), cada uma com cinco repetições. Utilizaram-se 200 alevinos de tilápia-do-nilo, linhagem tailandesa, revertidos sexualmente, com peso médio de 0,92 g e 35 dias de idade, distribuídos em 25 tanques de 150 L. Avaliaram-se o ganho de peso, a conversão alimentar aparente, a taxa de sobrevivência, o índice hepato-somático, o rendimento de carcaça e a porcentagem de gordura na carcaça. Os desempenho dos alevinos não diferiu entre as rações, o que indica que os níveis de energia não influenciaram as características de desempenho. O milheto pode ser utilizado na alimentação de alevinos de tilápia-do-nilo em substituição total à energia e proteína do milho, pois não prejudica o desempenho nem a qualidade da carcaça dos animais.

It was evaluated the inclusion of millet perls in rations with 30% of digestible protein and 3,000 kcal/kg of digestible energy for Nile tilapia fingerlings. The experiment was carried out in complete randomized design with five rations (0.00; 7.00; 14.00; 21.00 and 28.00% millet perls inclusion), each one with five replicates. It was used 200 sexual reverted Thai lineage Nile tilapia fingerlings, at 0.92g of initial weight and 35 days of age, distributed in 25 tanks (150 L). Weight gain, apparent feed conversion, survival rate, hepatic-somatic rate, carcass yield and carcass fat percentage were evaluated. The performance of the fingerlings did not differ among rations, indicating that levels of energy did not influence the characteristics of performance. Millet pearls can be used in feeds for Nile tilapia fingerlings totally replacing energy and protein of corn without effect on performance and carcass quality of the animals.

Foram utilizadas 800 larvas com 2 dias de idade com o objetivo de testar o uso de farelo de soja em rações para tilápias-do-nilo durante o período de reversão sexual (30 dias). O experimento foi conduzido segundo delineamento em blocos casualizados com quatro tratamentos e quatro repetições, no qual um tanque-rede com 50 larvas correspondeu a uma unidade experimental. Os tratamentos consistiram de rações isoprotéicas e isoenergéticas (38,6% de proteína digestível e 3.800 kcal/kg de energia digestível) com 0, 16, 34 ou 42% de farelo de soja. O aumento no nível de farelo de soja teve efeito linear positivo sobre os valores de peso e comprimento finais médios, mas não afetou a condição corporal e os índices de sobrevivência. Recomenda-se incluir o farelo de soja em níveis de até 42% na ração de tilápias-do-nilo na fase de reversão.

Eight hundred Nile tilapia larvae with two days old were used to evaluate the inclusion of soybean meal in diets fed Nile tilapia during the sex reversion period (30 days). The experiment was analyzed as a completely randomized blocks, with four treatments and four replications. A net tank with 50 larvae was considered an experimental unit. The treatments were formulated to be isoprotein and isonitrogenous (38.6% of digestible protein and 3,800 kcal/kg of digestible energy), with increasing levels of soybean meal inclusion 0, 16, 34 and 42%. Average final weight and length linearly increased as the dietary soybean meal levels increased. No treatment effect on survival and body condition was observed. It is recommend to include up to 42% of soybean meal in Nile tilapia diets in the sexual reversion phase.