Performance Of Nile Tilapia Fingerlings Research Articles

Effects of Different Salinity Levels on Performance of Nile Tilapia Fingerlings in a Biofloc Culture System

Abstract Especially in arid regions, developing tilapia culture with the ability to survive a wide range of salinities is crucial due to the limited availability of fresh water for aquaculture. The present study focused on evaluating the growth performance of Nile tilapia in a biofloc system under three salinity levels: 0 (BFT0), 4 (BFT4), and 8 g/L (BFT8). Fingerling fish were raised for 37 days in tanks with a water volume of 140 liters and a stocking density of one fish per liter. The results of the water quality parameters showed that dissolved oxygen and pH decreased with increasing salinity. Furthermore, the BFT8 group had the highest concentrations of settled solid (19.98 ml/L) and total suspended solid (428.37 mg/L), while the BFT8 group had the lowest TAN concentration (4.32 mg/L). The final weight and specific growth rate were significantly higher in the BFT8 and BFT4 groups compared to the BFT0 group. Survival rates were not significantly different across treatments, and all of them were higher than 97%. The protein and lipid content of Nile tilapia bodies and bioflocs decreased with increasing salinity, while the ash content increased. The highest body ash content in Nile tilapia (13.81% of dry weight) and bioflocs (31.78% dry weight) was found at 8 g/L salinity. Based on the present study, it is suggested that salinities of 4 and 8 g/L can improve water quality, growth performance, survival, and carcass composition of Nile tilapia fingerlings in the biofloc system. This finding suggests that brackish waters can be utilized for sustainable aquaculture for the rearing of Nile tilapia.

Probiotic in diets for Nile tilapia (Oreochromis niloticus) fingerlings

The objective was to evaluate the effects of the probiotics Bacillus subtilis and Bacillus cereus (4x1011 CFU kg−1) (BSC) in diets for Nile tilapia fingerlings. A total of 450 fish (average weight of 2.81 ± 0.06 g) were distributed in a completely randomized design, in 15 aquariums of 210 liters, consisting of five treatments and three replications. The isoproteic and isoenergetic experimental rations were formulated as follows: BSC1: 0% (control); BSC2: 0.6%; BSC3: 0.8%; BSC4: 1.0%; BSC5: 2.0% of probiotics per kg of feed at a concentration of 4x1011 CFU kg−1. The animals were fed the experimental diets for 30 days. At the end of the study, the productive performance was determined, and bromatological and histological analyzes of the fish were carried out. It was concluded that the probiotic did not influence the zootechnical performance of Nile tilapia fingerlings. The use of 0.8% of BSC appeared as a dietary supplementation strategy for Nile tilapia fingerlings, due to the efficacies found in the main results of body centesimal composition and in adaptations in the histomorphometry of the intestinal villi.

Growth performance of Nile Tilapia (Oreochromis niloticus) fingerlings fed with water spinach (Ipomoea aquatica) diets

Nile tilapia (Oreochromis niloticus) are herbivores with longer coiled intestines compared to carnivores; mouth characteristics necessary for plant shredding. Hence, several studies have been conducted to replace feed ingredients in the diet of Nile tilapia considering the increasing cost. In this study, Water spinach (Ipomoea aquatica) was evaluated as a potential feed ingredient for Nile tilapia. A six months feeding trial was conducted to assess the effects of water spinach fish feed composition on the performance of Nile tilapia fingerlings. Five diets were formulated containing 0% (control diet), 5%, 10%, 15% and 20% water spinach composition. Each treatment was carried out in triplicate using 30 Nile tilapia juveniles per replicate with an initial mean weight of 2±1g. The fish were fed at 5% body weight twice per day. Water quality monitoring was done every morning before feeding. There was no significant (p > 0.05) variation in water quality parameters between all the treatments. The best growth performance was recorded from a fish-fed 5% diet (180.49±0.83 g), while fish fed with a 20% diet had poor growth performance (128.98± 0.80g). The highest SGR was obtained in fish fed with a 5% diet (1.34±0.05) while the lowest was obtained in fish fed with a 20% diet (1.09±0.05). Except for SGR, WG, FL, and FW, there was no significant difference (P>0.05) in other growth parameters of all the treatments. Final weight had a significant difference as determined by One-Way ANOVA (F (4,316) =6.363, P=0.00) between 15% and 20% water spinach composition compared to 5% water spinach composition. Therefore, 5% water spinach composition had the best growth performance.

Effect of dietary crude glycerin on the productive performance of Nile tilapia fingerlings.

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.

Dietary inclusion of Orange peels derived pectin and Lactobacillus plantarum for Nile tilapia (Oreochromis niloticus) cultured under indoor biofloc systems

A 12-week feeding trial was carried out to investigate possible effects of dietary orange peels derived pectin (OPDP) and Lactobacillus plantarum CR1T5 (LP) singularly or combined on innate immune response, disease resistance, and growth performance of Nile tilapia fingerlings under indoor biofloc system. The fingerlings were fed the following diets: diet 1 (0 g kg−1 OPDP and 0 CFU g−1 L. plantarum), diet 2 (10 g kg−1 OPDP), diet 3 (108 CFU g−1 L. plantarum), and diet 4 (10 g kg−1 OPDP +108 CFU g−1 L. plantarum). At the end of feeding trial, skin mucus parameters, serum immune parameters, and growth performance were measured. Ten randomly selected fish were used in a challenge test with Streptococcus agalactiae. The results indicated that supplementations of OPDP + LP or/and significantly (P < .05) increased growth performance, skin mucus and serum immunity responses. The highest values were revealed in fish fed both OPDP and LP vs. individual applications. However, no significant (P > .05) differences were observed between fish fed OPDP and LP. The challenge test revealed that the relative percent survival (RSP) in diet 2, diet 3, and diet 4 was 43.33%, 50.0%, and 70.0%, respectively. Among the supplemented groups, fish fed 10 g kg−1 OPDP + LP showed significant (P < .05) higher RPS and resistance to S. agalactiae than the other groups. The present results suggested that the combination of OPDP and LP could be considered as potential feed-additives for aquaculture farmed fish under indoor biofloc system.

THE INTENSIVE CULTURE OF NILE TILAPIA SUPPLEMENTED WITH THE MICROALGAE Chlorella vulgaris IN A BIOFLOC SYSTEM

The aim of this study was to evaluate the performance of Nile tilapia fingerlings cultured in biofloc technology using different inoculation densities of Chlorella vulgaris. The experimental design was completely randomized with biofloc system and four densities of Chlorella vulgaris (0, 2.5, 5 and 10 x 104 cell mL-1), each with four replications. The study lasted 63 days and was carried out in tanks with a working volume of 40L, at a stocking density of 10 fish per experimental unit and a mean initial weight of approximately 1.86 g. The water quality variables showed no significant difference between treatments, especially total ammonia nitrogen and nitrite nitrogen, which were within acceptable levels for culture of the species. The variables of zootechnical performance were not affected by the different inoculation densities of the microalgae, achieving a final mean weight of approximately 21 g for all treatments, and survival rates greater than 80%. The weekly inoculation densities of the microalgae Chlorella vulgaris therefore had no influence on the growth of tilapia fingerlings cultured in a biofloc system.

Nile tilapia fingerling cultivated in a low-salinity biofloc system at different stocking densities

A 42-day trial was conducted to evaluate the effects of a low-salinity biofloc system with different stocking densities on water quality and zootechnical performance of Nile tilapia fingerlings (10 g/L). Four treatments were tested at different densities: 500 fish/m³, 750 fish/m³, 1,000 fish/m³ and 1,250 fish/m³, all in triplicate. Fingerlings of Oreochromis niloticus (initial mean weight of 1.17 ± 0.05 g) were stocked in twelve experimental black-plastic tanks (40 L) with no water exchange during the experimental period. Molasses was added daily to the system at 30% of the amount of feed, and fish were given four daily rations of a formulated feed composed of 36% crude protein and 9% lipids. Water quality variables (dissolved oxygen, pH, salinity, TAN, NO2, NO3 and PO43) did not demonstrate significant differences between the treatments. However, significant influences (α ≤ 0.05) of the stocking densities were observed for total suspended solids, settleable solids, final weight, yield, and protein efficiency ratio. The results showed survival over 96%, final weight values between 12 and 18 g, yield between 9.49 and 15.27 kg/m3, water consumption of 52 to 101 L/kg fish, and total time of settling chambers between 238 and 305 h/kg fish. These results indicate a negative effect of stocking density on final weight, survival, alkalinity, NO2, PO43 and water consumption, and a positive effect on yield in Nile tilapia fingerling culture (1-20 g) in a low-salinity biofloc system with densities up to 1000 fish/m³.

Vegetable choline improves growth performance, energetic metabolism, and antioxidant capacity of fingerling Nile tilapia (Oreochromis niloticus)

Fish represents an important source of proteins and essential micronutrients for human health, and Nile tilapia (Oreochromis niloticus) is one of the most widespread aquaculture species grown worldwide to meet the growing demand for fish. In this sense, the use of supplemented diets it is important and an interesting approach to improve the growth performance, as the use of vegetable choline (VC). A total of 160 fingerlings Nile tilapia (7.10 ± 0.45 g; 6.13 ± 0.59 cm) were randomly separated into four groups in quadruplicate with 10 fish per aquarium (60 L) as follows: the group T0 (basal diet without VC supplementation), T400 (basal diet supplemented with 400 mg VC/kg of feed), (basal diet supplemented with 800 mg VC/kg of feed), and T1200 (basal diet supplemented with 1200 mg VC/kg of feed), being fed with rate of 6% of total biomass for 60 consecutive days in two equal portions and offered to fish twice a day at 9:00 am and 17:00 h. Thus, the aim of this study was to evaluate whether phosphoryl transfer network, as well as the improvement of antioxidant/oxidant status, can be considered pathways involved in the improvement of growth performance in Nile tilapia (7.10 ± 0.45 g) fed 0.0, 400, 800, and 1200 mg VC/kg of feed for 60 days. VC-supplemented diets were able to increase fish growth and feed intake after 60 days post-feeding compared to the control group. Also, fish from groups supplemented with 800 and 1200 mg VC/kg of feed presented an increase on hepatic pyruvate kinase activity compared to the control group. On the other hand, fish supplemented with 1200 mg VC/kg of feed presented an increase on hepatic glucose levels, while the hepatic lactate levels decreased compared to the control group. Additionally, VC supplementation improves the zootechnical performance. Finally, fish from groups supplemented with 800 and 1200 mg VC/kg of feed presented lower hepatic lactate dehydrogenase and lipid peroxidation levels, while the antioxidant capacity against peroxyl radicals levels were higher compared to the control group. Based on these evidences, VC supplementation can be an interesting alternative to increase growth performance of Nile tilapia fingerlings especially at levels of 800 and 1200 mg VC/kg of feed, which were able to improve the hepatic energy metabolism and antioxidant/oxidant status and subsequently increased the fish growth performance.

Organic Soybean Meal in Diet for Nile Tilapia

Aiming to assess organic soybean meal (OSM) for Nile tilapia, two studies were carried out: Study I - digestibility of OSM compared to conventional soybean meal (CSM) for Nile tilapia; and Study II - effect of OSM and CSM, supplemented or not with fish meal (FM) on the performance of Nile tilapia fingerlings. The apparent digestibility coefficients of the protein were 88.24 and 88.10%, resulting in 39.91 and 39.87% digestible protein for OSM and CSM, respectively. The apparent digestibility coefficients of energy were 75.92 and 70.48%, resulting in 3579.46 and 3141.44 kcal kg-1 of digestible energy for OSM and CSM, respectively. The diet containing CSM+FM presented the best results for final weight and weight gain. However, the highest levels of crude protein in the fish carcass were observed in the animals fed with the OSM + FM diet. The OSM diet presented the best results for total protein and albumin in the blood. The OSM diet has good apparent digestibility coefficients and its use in tilapia feeding presents a satisfactory productive performance and a higher deposition of protein in the carcass when supplemented with 20% of fish meal.

Effect of Moringa Leaves, Moringa Oleifera Meal as a Feed Additive on the Performance of Nile Tilapia, &lt;i&gt;Oreochromis niloticus&lt;/i&gt;

A twelve- week feeding study was conducted to define the influence of adding different levels moringa leaves powder 0, 2, 4 or 6 g kg -1 to the basal diet on Nile tilapia fingerlings performance. Fish were distributed randomly at a rate of 15 fish each in 12 aquaria with average 2.1 ± 0.1 g initial weight. Each diet was provided to fish in triplicate at a level of 5% of biomass. The growth performance did not differ significantly (P > 0.05) among all treatments. There were significant differences in protein, lipid and ash content (P < 0.05). A reduction was observed in the lipid values with increasing the level of moringa leaves meal in the experimental diets. The inclusion of moringa leaves meal reduced the glucose, cholesterol and triglycerides in the blood plasma content significantly. No specific neurotic changes were observed in the liver, intestine or ovary of tested Nile tilapia fed the experimental diets. It was concluded that moringa leaves meal can be added to the diets for Nile tilapia without any antagonistic properties.

Effect of dietary fructooligosaccharide supplementation on feed utilization and growth performance of Nile tilapia (Oreochromis niloticus) fingerlings

The present study was conducted to investigate the effect of prebiotic fructooligosaccharide (FOS) on the feed utilization and growth performance of Nile tilapia fingerlings through evaluation the digestive enzymes activities and histological feature of the intestine. Fish were distributed into four groups in well prepared fiberglass tanks and were fed on basal diet without additive (control), 1%, 2%, and 3% FOS for 8 weeks. Results showed that the final weight, weight gain and the specific growth rate were significantly increased with 2% dietary FOS with lower feed conversion ratio compared to the control group. Digestive enzymes activities showed no significant effect (P > 0.05) of dietary FOS on intestinal amylase and lipase activities. While, protease activity was significantly higher (P < 0.05) especially in group fed 2 % (22.7 ± 2.28 U) dietary FOS compared to the other treated and control groups. Histological examination of the mid-intestine revealed significant increase of villi length and number of mucous cells with increased dietary FOS levels (P < 0.05) especially in groups fed 2 and 3% FOS. In conclusion, FOS supplemented diets could improve intestinal enzymes activities, absorptive ability, and histological feature of intestinal villi and consequently increase the feed utilization and growth performance of Nile tilapia fingerlings.

Óleos essenciais na alimentação de alevinos de tilápia do Nilo

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.

Antibacterial Activity of Essential Oils and their Effects on Nile Tilapia Fingerlings Performance

Antibacterial Activity of Essential Oils and their Effects on Nile Tilapia Fingerlings Performance

Performance of Nile tilapia Oreochromis niloticus fingerlings in a hyper intensive recirculating aquaculture system with low water exchange

The aim of this paper was evaluate the performance of Nile tilapia fingerlings ( Oreochromis niloticus ) raised at hyper intensive stocking density in a recirculating aquaculture system (RAS) with minimum water replacing. The experimental system was performed in a single-batch nursery system to obtain 50 g fish size in 60 days. Fish (2.07 ± 0.04 g) were stocked in triplicate at 400 (T1), 500 (T2) and 600 (T3) fish m -3 (0.84, 1.05, 1.22 kg m -3 ). RAS functioned with 12,000 L of recirculating water and 252 L day -1 of water replacing (2.1% daily). The efficiency of the biofilter for removing the total ammonia nitrogen (TAN) was 48 ± 12.5 mg L -1 . Stocking density did not affect significantly the survival (89.5 to 93.6%). The growth rate of T1 (0.96 g day -1 ; 5.01% day -1 ) and T2 (0.92 g day -1 ; 4.95 % day -1 ) was significantly higher than T3 (0.83 g day -1 ; 4.80% day -1 ). The specific growth rate (SGR)of T1 was 41% influenced by temperature. For T2 and T3 the SGR were influenced by the variation of dissolved oxygen (DO) that explained 47 and 44% of the fish weight variation, respectively. The SGR from T3 was also affected by the concentration of ammonia nitrogen (31%). The high stocking density affected the overall size of fish and the size homogeneity, but had no negative effect on the length–weight relationship (L-W). Data support the conclusion that fingerling stocked at 400 and 500 fish m -3 shows high performance during 9-weeks when the biomass not exceed 37 kg m -3 . At this time fish have reached the desired final nursery weight (50 g) for transfer to grow-out facilities.

Exigência de treonina, com base no conceito de proteína ideal, de alevinos de tilápia-do-nilo

Avaliou-se o efeito dos níveis de treonina digestível, com base no conceito de proteína ideal, em rações com 1,35% de lisina digestível sobre o desempenho de alevinos de tilápia-do-nilo (Oreochromis niloticus). Utilizaram-se 432 alevinos revertidos de tilápia, linhagem tailandesa, com peso inicial de 1,64 ± 0,03 g, em delineamento inteiramente ao acaso, com seis tratamentos, cada um com seis repetições, e doze peixes por unidade experimental. Os tratamentos consistiram de cinco rações com diversas relações treonina:lisina digestível (69,0; 74,0; 79,0; 84,0 e 89,0%) e relação metionina + cistina:lisina digestível de 70,0% e uma ração com relação treonina:lisina digestível de 84,0% e de metionina + cistina:lisina digestível de 75,0%, todas isoenergéticas e isoprotéicas. Os peixes foram mantidos em 36 aquários de 130 L, dotados de abastecimento de água, temperatura controlada e aeração individuais, e alimentados à vontade, seis vezes ao dia, durante 30 dias. Avaliaram-se o desempenho, a composição corporal, as deposições de proteína e gordura e a eficiência de retenção de nitrogênio dos peixes. O consumo de ração, o teor de proteína corporal e a deposição de proteína corporal aumentaram de forma linear de acordo com a relação treonina:lisina na ração, contudo, não foram influenciados pelo aumento da relação metionina + cistina:lisina da ração. Os níveis de treonina total ou digestível que proporcionaram os melhores resultados de desempenho em alevinos de tilápia-do-nilo foram de 1,11 e 0,99%, enquanto os níveis que promoveram melhor deposição de proteína corporal foram de 1,43 e 1,28%, que correspondem às relações treonina:lisina total de 71,0 e 69,0% e treonina:lisina digestível de 90,0 e 89,0%.

Triguilho na alimentação da tilápia do nilo (Oreochromis niloticus L.): digestibilidade e desempenho

No presente experimento objetivou-se determinar os coeficientes de digestibilidade aparente (CDa) da proteína bruta (PB) e da energia bruta (EB) do triguilho para a tilápia do Nilo (Oreochromis niloticus) e avaliar a inclusão do triguilho sobre o desempenho de alevinos de tilápia do Nilo. Para a determinação dos CDa, foram utilizadas 40 tilápias com peso e comprimento médios de 80,00g e 15,9cm, respectivamente, submetidas à coleta das fezes por sedimentação. Para a avaliação do desempenho, foram utilizados 125 alevinos de tilápia do Nilo, com peso inicial médio de 0,80g, distribuídos em 25 aquários com capacidade de 30L, em um delineamento inteiramente casualizado, com cinco tratamentos e cinco repetições. As rações experimentais continham níveis de inclusão de 0,00; 7,97; 14,94; 23,91 e 31,88% de triguilho substituindo até 100% do milho. Os CDas da PB e EB do triguilho foram de 91,03 e 78,72%, respectivamente, apresentando 11,92% de proteína digestível e 3134Kcal kg-1 de energia digestível. Não foi observada diferença (P&gt;0,05) no desempenho dos peixes alimentados com as rações contendo os diferentes níveis de inclusão do triguilho. O triguilho é um alimento com bons CDa da PB e EB e pode ser incluído em até 31,88% em rações para alevinos de tilápia do Nilo sem causar prejuízo no desempenho.

Desempenho de alevinos de tilapia do Nilo submetidos a diferentes niveis de inclusao do farelo de algodao

With the objective of evaluating the Nile tilapia fingerlings performance submitted to different levels of cottonseed meal (CM) inclusion (0,00; 20,00; 40,00; 60,00 and 80,00%) in rations with 30,00% of digestible protein and 3000 kcal/kg of digestible energy, the experiment was carried out in the Laboratorio de Aquicultura/UEM, 250 Nile tilapia fingerlings, were used, sexually reverted, divided in 25 tanks with 150 L, in a completely randomized design with five treatments and five replications. The evaluated variables were diary weight gain (DWG), feed gain (FG), protein efficiency rate (PE), survival (S), hepatic-somatic index (HSI), condition factor (CF), dry matter (DM), protein in the carcass percentage (PC) and fat in the carcass percentage (FP). The medium values of temperature, dissolved oxygen, electrical conductivity and pH during the experimental period, were 26,93 ± 0,29oC; 5,47 ± 0,86 mg/L; 245,80 ± 54,29 µS/cm and 7,78 ± 0,19, respectively. The WG and PE presented linear decrease when the CM was included in the ration, the FG and HSI presented linear increase. The DM, PC and WG presented quadratic effect with point maxim to 45,25, 47,84 and 45,15, respectively. The S and CF didn’t present significative differences (P>0,05). Concluded that the cottonseed meal influences in a negative way the Nile tilapia fingerlings performance. .

Farinhas de peixe, carne e ossos, vísceras e crisálida como atractantes em dietas para alevinos de tilápia do Nilo (Oreochromis niloticus)

O experimento foi conduzido com o objetivo de comparar a utilização de 5% de inclusão das farinhas de peixe (FP), vísceras (FV), carne e ossos (FO), crisálida (FC) e controle (farelo de soja e milho) como atractantes sobre o consumo de ração e desempenho de alevinos tilápia do Nilo. Foram utilizados 168 alevinos de tilápia do Nilo (linhagem tailandesa) revertidos sexualmente, com peso inicial médio de 0,72 ± 0,18g, distribuídos em um delineamento experimental inteiramente casualizado, com cinco tratamentos e cinco repetições, sendo a unidade experimental constituída por um aquário de 50 L com sete animais. As rações foram formuladas com 32% de proteína bruta e 3000 kcal de energia digestível/kg, sendo as mesmas isoprotéicas, isocalóricas, isofíbricas e isoaminoacídicas para lisina e metionina + cistina. Os valores médios de ganho de peso observados nos tratamentos controle ou com FV e FP como atractantes foram superiores aos dos tratamentos FC ou FO. A conversão alimentar dos animais alimentados com ração contendo FV foi melhor que os tratamentos FC ou FO, porém não diferiu significativamente dos tratamentos controle e FP. O comprimento final médio dos animais do tratamento controle foi superior, quando comparados ao tratamento FC, não diferindo dos demais. O consumo alimentar e a taxa de sobrevivência não diferiram entre os tratamentos. Concluiu-se que não seria necessária a utilização dos alimentos testados, a 5% de inclusão, para estimular o consumo alimentar ou promover o crescimento de alevinos de tilápia do Nilo.