Diet Of Nile Tilapia Fingerlings Research Articles

Effect of fishmeal replacement with dried red wigglers (Eisenia fetida) worm meal on growth and feed utilization, production efficiency, and serum biochemistry in Nile tilapia (Oreochromis niloticus) fingerlings

This study investigated the effect of replacing fishmeal with red wigglers (Eisenia fetida) worm meal (RWWM) in the diet of Nile tilapia (Oreochromis niloticus) fingerlings. Red wigglers worms (RWW) were culture on a vegetable by-product medium, harvested and dried to obtain red wigglers worm meal. The fish (average weight ± SE: 7.70 ± 0.06 g) were fed with seven diets (30% crude protein and 7.5% crude lipid), in which fishmeal was replaced with 0%, 5%, 10%, 15%, 20%, 25%, and 30% RWWM. The fish was reared in 1000 L fiberglass tanks in a recirculating aquaculture system and were hand-fed twice daily for 90 days. At the end of the experiment, the growth, feed conversion ratio, and energy utilization improved when feeding 15% and 20% RWWM compared with the control diet (P < 0.05). Using broken line regression between growth efficiency and feed utilization, showed the optimum level of RWWM replacing FM in Nile tilapia fingerlings diet was around 21 – 22% of the diet. The whole-body crude protein and ash content were elevated in the fish fed with 10–25% RWWM, while crude lipid and energy contents were elevated in the fish fed with 5–25% RWWM compared with the control group (P < 0.05). The essential and non-essential amino acids profiles of the fish were improved by 15% and 20% RWWM compared with the control (P < 0.05). The plasma glucose was decreased by 15–20% and significantly enhanced in fish fed with 25–30% RWWM diets compared with the control (P < 0.05). The total protein, albumin and globulin increased in the fish fed 15–20% diets and decreased in fish fed the 30% RWWM (P < 0.05). Therefore, this study demonstrates that RWWM could replace 20% fishmeal in the diets of Nile tilapia fingerlings without negatively affecting fish growth and physiological performance.

Protein hydrolysate from cattle residues can be included in diets for Nile tilapia ( Oreochromis niloticus ) fingerlings

The study aimed to determine the optimal level of inclusion of protein hydrolysate from cattle residues in diets for Nile tilapia fingerlings. Nile tilapias with an average initial weight of 5 g were used, distributed in 15 net cages. The experiment was carried out for 42 days in a completely randomized design with five treatments (0.0%; 2.5%; 5.0%; 7.5% and 10.0% inclusion of protein hydrolysate) and three replications, with that 50 tilapia were stored in each net tank. After the experimental period, the fish were anaesthetized for blood collection and measurements of the parameters of zootechnical performance. Six animals from each experimental unit were euthanized for further bromatological evaluation of the carcass. The zootechnical performance data, the proximate chemical composition of the carcass and blood biochemical parameters were submitted to analysis of variance (α = 0.05), and the Tukey test (α = 0.05) was applied. There were no significant differences between treatments for the parameters of zootechnical performance and proximate chemical composition of the carcass (p > 0.05). As for blood parameters, a significant difference was detected between treatments in alkaline phosphatase activity, calcium and total protein (p < 0.05). The lower alkaline phosphatase activity determined in the treatments with protein hydrolysate indicates that this product can improve the physiological response of animals to the stress caused by production conditions in captivity. It is concluded that it is possible to include 10% of the protein hydrolysate in the rations without causing any type of damage to the performance, chemical composition of the carcass, or well-being of the fish.

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.

Hematological parameters, liver integrity and growth of Nile tilapia fingerlings fed diets supplemented with propolis extract

Aim of study: To assess the effects of propolis extract supplementation in diets for Nile tilapia (Oreochromis niloticus) fingerlings on growth performance, hematological and histological parameters. Area of study: The study was carried out in Paraná (Brazil). Material and methods: The experimental design was based on six treatments including the control diet and propolis supplementation (2%, 4%, 6%, 8% and 10% in the diet). Three hundred Nile tilapia fingerlings, with an initial weight of 0.61± 0.02 g, were distributed in 30 plastic mesh hapas (0.15 m3 each) arranged in a concrete tank of 25 m3 of water volume. The duration of the experimental period was 90 days. Main results: The increasing levels of propolis did not influence the growth performance and proximate composition of fishes. Red blood cells and hematological indices were not affected by propolis supplementation. However, total leukocytes and thrombocytes were higher in fish fed on propolis diets, being significant in fish fed 2% and 8%, and 6% and 8% supplemented diets groups, respectively. Research highlights: The supplementation of propolis alcoholic extract in the range of 2, 4, 6 and 8% in the diet for Nile tilapia fingerlings promote healthier fish with increased immunity in the evaluated culture conditions.

Effect of Cassava Starch Sources on Growth and Feed Utilization of Nile Tilapia Fingerlings (Oreochromis niloticus) Reared Under Two Dietary Protein Levels

A 42-day experiment was performed to evaluate the growth performance and feed utilization of Nile tilapia (Oreochromis niloticus) fingerlings fed iso-lipidic diets (5% lipid) contain 17% or 25% of cassava starch extract from fresh root (R starch) or from dry chips (D-starch) at 37% and 30% protein levels. The diets were ie: 37% protein -FM25R17 &amp; FM25D17, 30% Protein- FM15R25 &amp; FM15D25. 144 fish (1.11+0.02g) were distributed in 12 tanks (54 L). Protein level or starch source had no impact on final weight, length, average daily gain, specific growth rate, food conversion ratio, hepato somatic index, viscero somatic index, and Whole-body composition of fish. Protein Efficiency Ratio was not affected by starch source; however, it was significantly higher in diets with low protein content. Apparent Digestibility Coefficient of dry matter was not affected by starch source but was significantly high in low (30%) protein diet. Inclusion of R starch substantially reduced the cost of feed and increased economic profitability. Tilapia fed FM15R25 diet showed similar growth and nutrient utilization to fish fed 37% protein diets and cost of FM15R25 diet was lower than other diets. Therefore, FM15R25 is the best practical diet among the tested diets for Nile tilapia fingerlings.

Dietary sodium chloride effect in Nile tilapia fed with fish meal-free diets

Aim of study: To evaluate the effect of the dietary NaCl level for Nile tilapia fingerlings.Area of study: Palotina sector of Federal University of Paraná, in southern Brazil.Material and methods: An experiment was carried using 750 Nile tilapia fingerlings (4.61 ± 0.09 g) distributed in 30 1,000-L circular tanks in a completely randomized design with six treatments and five replicates. NaCl was added to extruded fish meal-free diets at 0.0, 2.5, 5.0, 7.5, 10.0 and 12.5 (g/kg). After the experimental period, fish were submitted to a 24 h-fast and weighed. All data were submitted to an analysis of variance and Tukey’s test followed by Levene’s test and regression test, using the Statistica 7.0® software package.Main results: Fish fed the NaCl-free diet presented better growth performance (p&lt;0.05) compared to the other diets. Linear decrease effects on final weight (y = 50.1754 – 0.1672x, r2 = 0.6984), specific growth rate (y = 45.5418 – 0.1688x, r² = 0.6966), weight gain (y = 4.9465 – 0.008x; r² = 0.6886) and apparent feed conversion (y = 0.7113 + 0.0043x; r² = 0.7655) were noted. Efficiency and apparent protein retention were better in the NaCl-free diet (p&lt;0.05). Significant differences (p&lt;0.05) were observed for fillet fat and crude protein content. Increasing NaCl levels led to significant decreases (p&lt;0.05) in Nile tilapia fingerling protein efficiency rates (y = 3.7804 - 0.0116x; r² = 0.6549).Research highlights: Thus, NaCl should not be included in fish meal-free diets for Nile tilapia fingerlings.

Digestive enzyme activities in Nile tilapia, Oreochromis niloticus fed diet supplemented with guar sprout meal

The present study was carried out to examine the specific digestive enzyme activity of Nile tilapia (Oreochrmis niloticus) fingerlings, fed with different percentages of Guar sprout meal (GSM). The experiment was set with five isonitroneous and isolipidic diets as T1, T2, T3, T4 and T5 containing guar sprout meal at an inclusion rate of 0, 25, 50, 75 and 100%, respectively. The result showed a higher protease activity in the fish nourished with 0%, 25% and 50%. GSM beyond 50% showed poor protease activities especially in all parts of the gut (gastrointestinal tract). There was significant acceleration in amylase and lipase activities in the digestive tract (liver, stomach and intestine) with increased GSM levels. The results accomplish that 25-50% inclusion of GSM can be a favorable and economically sustainable protein source in the diet of Nile tilapia fingerlings.

Tilapia oil, poultry offal oil and their combinations, replacing soybean oil, for tilapia fingerlings

With the objective of evaluating the soybean oil replacement by tilapia oil and poultry oil for Nile tilapia fingerlings, 240 reversed tilapia fingerlings with an individual weight of approximately 0.6 ± 0.11 grams that were stored in 30 aquariums of 50 liters (6T x 5R), in the quantity of 8 units / aquarium, where they were fed with 65% lipid rations containing soybean oil (SO), tilapia oil (TO), poultry oil (PO), and their SO+TO, SO+PO, TO+PO mixtures of equal parts as a lipidic source in practical diets during 50 days. The performance parameters, the carcass composition and the fatty acids content both on the fillet and the innards were verified. The performance, survival, weight gain, and the feeding conversion characteristics were not influenced by the diet. The carcass composition on both the fillet and the innards were not influenced by the source of lipids in the content of moisture and lipids. In general, the fatty acids profile reflected the diets one with the decrease of polyunsaturated fatty acids and the increase of saturated and monounsaturated fatty acids with the replacement. Therefore, tilapia oil, poultry oil, as well as their mixtures can totally or partially replace the soybean oil in diets for Nile tilapia fingerlings without injury to the performance.

Heat-treated bean (Phaseolus vulgaris) residue meal as an alternative protein source in pelleted diets for Nile tilapia fingerlings: growth, body composition, and physical characteristics of diets.

The study aimed to evaluate heat-treated bean residue meal (Phaseolus vulgaris)-BRM-as an alternative protein source in diets for Nile tilapia fish. A completely randomized design was used, totaling four (n = 4) dietary treatments: diet without BRM (CON), raw BRM (RBRM) and heat-treated BRM at 100°C for 15min (BRM15), and 30min (BRM30) before inclusion in diets. Nile tilapia fingerlings (1.3g initial weight) were hand-fed the experimental diets for 66days, divided equally into three meals per day. Performance parameters, body composition, nutrient retention, and physical characteristics of diets were evaluated. Growth and feed conversion were lower (P <0.05) in fish fed BRM. Protein productive value was higher (P <0.05) in fish fed CON diet than in fish receiving BRM. However, 30min heat treatment of BRM increased (P <0.05) protein retention in fish. Fish fed BRM30 also had higher protein content (P <0.05) and reduced body lipid content (P <0.05) than those fed CON diet. The physical characteristics (durability, dry matter leaching, waterproof time, and water stability time) were significantly improved (P <0.05) in the BRM30 diet compared with other dietary treatments. The dietary inclusion of BRM at the level of 15% is not recommended for tilapia due to low growth performance and feed efficiency, regardless of preheating treatment. However, research on longer heat treatment time is needed due to the improvements observed in nutrient retention and physical characteristics of diets.

Sustitución del aceite de soya por aceite de vísceras de aves en raciones para alevinos de tilapia del Nilo

This experiment was carried out with the objective of evaluating the soybean oil replacement by poultry fat for Nile tilapia fingerlings. Two hundred reversed tilapia fingerlings with an individual weight of approximately 0,6 ± 0,11 grams were stocked in 50-liter aquariums, with 8 fishes in each experimental unity, where they were fed with 6,52% lipid rations containing 0, 25, 50, 75, 100 percent of poultry oil replaced by soybean oil as a lipid source in their diets during 50 days. The performance parameters, the carcass composition and the content of fatty acids on both the fillet and the innards were verified. The performance, survival, weight gain and feeding conversion characteristics were not influenced by the diet. The carcass composition was influenced by the lipid source in the moisture content and lipids. In general, the fatty acids profile reflected the diets one with a decrease of polyunsaturated fatty acids and an increase of saturated and monounsaturated fatty acids with the replacement. Therefore, the poultry oil can partially or totally replace the soybean oil in practical diets for Nile tilapia fingerlings without injury to the 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.

Valine in diets for Nile tilapia

This study verified the effect of valine on the zootechnical performance, percentage composition and growth of skeletal muscle fibre in fingerlings of Nile tilapia. A total of 270 fish (average initial weight 1.57 ± 0.05 g and total initial length 4.16 ± 0.46 cm) were used, distributed in 18 tanks (250 litres), in a completely randomised design with six treatments and three replications. Six diets (26.81% DP and 3200.00 kcal DE) were formulated with increasing levels of valine (0.82, 0.86, 0.98, 1.04, 1.10 and 1.26% of the diet). The zootechnical performance, percentage composition of the fish, and muscle-fibre distribution were evaluated. There was no effect from the different levels of valine (P>0.05) on zootechnical performance, percentage composition or the frequency distribution of muscle fibre. The addition of 0.82% valine (2.65% crude protein valine) is recommended in the diet of Nile tilapia fingerlings.

Growth, body composition and hepatopancreas morphology of Nile tilapia fingerlings fed crude glycerol as a replacement for maize in diets

This study consisted in determining the best level of replacement of maize by crude glycerol as an energy source for Nile tilapia fingerlings evaluating the growth performance, body composition and hepatopancreas histology. Three hundred Nile tilapia with an average weight of 11.46±2.18g were placed in 30 plastic aquaria (60L), in a completely randomized design with six treatments (levels of replacement of maize by crude glycerol at 0, 20, 40, 60, 80 and 100%) and five replications. The feeding regime consisted of three daily feedings ad libitum. An increase (P<0.05) in crude protein and body moisture, and a decrease in lipids and mineral content in whole body of fish fed with increasing levels of glycerol was observed. Regarding the productive performance hepatosomatic index showed a quadratic effect (P<0.05) and there was a linear reduction (P<0.05) in feed conversion with increasing substitution of maize by glycerol. No statistical differences were found (P>0.05) in the area of hepatocytes and no changes were observed in the morphology of the hepatopancreas. It is possible to replace totally maize by glycerol in pelleted diets for Nile tilapia fingerlings between 10 and 30g without causing prejudice to the productivity and quality of fish.

Evaluation of Soy Protein Concentrate and Meat and Bone Meal as a Replacement for Fish Meal in the Diet of Nile Tilapia Fingerlings

AbstractThis experiment evaluated soy protein concentrate (SPC) and meat and bone meal as a replacement for fish meal protein (FP) in the diet of Nile tilapia fingerlings. Five diets were evaluated including a control diet (50.0% crude protein [CP], of which half the protein came from fish meal [FM]), and four diets in which FM was replaced by increasing amounts of SPC (25.5, 50.0, 75.5, and 100.0%) in combination with meat and bone meal. At the conclusion of a 60‐d growth trial, the following parameters were determined: final weight (FW), final length (FL), weight gain (WG), feed intake (FI), apparent feed conversion (AFC), survival (SUR), and production cost. The estimate of the best replacement value was determined by polynomial regression and the linear response plateau. The results showed significant (P &lt; 0.05) improvement for WG and AFC ratio as FM was gradually replaced by SPC. The parameters FL and FI reached their optimum value at a replacement level of 100% SPC. These results show that it is feasible to use a combination of SPC and meat and bone meal in a balanced feed formulation as an alternative protein source in the diets of Nile tilapia fingerlings.

Effect of Spirulina platensis as feed supplement on growth performance, immune response and antioxidant status of mono-sex Nile Tilapia (Oreochromis niloticus)

To evaluate the effect of Spirulina platensis inclusion in diets for Nile tilapia fingerlings, a completelyrandomized experimental design was developed with 4 treatments and three replicates. Diets with 4inclusion levels (control diet (Sp0), 0.5% (Sp0.5), 1% (Sp1) and 1.5% (Sp1.5)) were prepared. 180 Niletilapia fingerlings with average initial weight of 8.46±0.17 g were assigned to twelve experimental tanks.The experiment lasted for ten weeks. At the end of the experiment; growth performance, the whole bodycomposition was determined and serum samples for lysozyme, IgG, IgM values and catalase activitywere collected and antioxidant status of Nile tilapia muscle were determined. The results showed thatgroup supplemented with 1% S. Platensis have higher body weight and lower FCR than the controlgroup and other groups. S. platensis inclusion increased activity of glutathione reductase, and reduceMDA formation. Levels of lysozyme, IgG and catalase activity were higher in S. platensis supplementedgroups but don’t have significant effect on IgM level. In conclusion, Spirulina platensis supplementationincreased antioxidant protective capacities. It also affected some innate and humoral immunityparameters as well as don’t have negative effect on fish growth

EFFECT OF FISHMEAL REPLACEMENT WITH CHEESE PROCESSING BY-PRODUCT MEAL ON FISH PELLET QUALITY USING RING DIE PELLETING MACHINE

This study was performed to use the cheese processing by-product meal (CPBM) as an alternative source of protein instead of the expensive herring fish meal (HFM) in the practical diet of Nile tilapia fingerlings. Three feed blends containing 30% of protein were formulated with three different percentages of CPBM replacement of 0.0 (HFM=100%), 50 and 100% The ingredients of these blends were pelleted using a ring die pelleting machine at roller clearance of 0.0, 1.5 and 3 mm and different moisture contents of 15, 20 and 25% to investigate the effect of the mentioned operating parameters on machine performance measurements, pellets quality as well as the fish growth performance. The obtained results revealed that ,CPBM percentage of 100% ,roller clearance of 0 mm and moisture content of 15% to achieve the highest values of machine productivity of 62 kg/h, pelleting efficiency of 94.50%, lowest specific energy consumption of 26.70 kW.h/Mg and the lowest cost per mass unit of 2978.00 L.E/Mg, while the highest values of durability(93.50%) and pellets bulk density (940 kg/m3)were recorded at roller clearance of 1.5 mm, CPBM percentage of 100% and moisture content of 15%.The results showed that the complete replacement of HFM by CPBM saved the cost per mass unit with about 822 L.E/Mg. For fish growth performance, results showed that the complete replacement of CPBM fish diets gave no significant (P > 0.05) effect on growth performance compared to fish fed the HFM, also no disparity in growth response of fish, efficiency of feed utilization, survival rate and did not affect fish composition of dry matter, protein, or fat .So, CPBM can be used as a cheap source of protein in Nile tilapia diets instead of HFM .

EVALUATION OF FERMENTED MANGO (Mangifera indica) SEED MEAL IN THE PRACTICAL DIET OF NILE TILAPIA, (Oreochromis niloticus) FINGERLINGS

This study evaluated the use of fermented mango (Mangifera indica) seed meal (FMS) to substitute yellow maize in the practical diet for Nile tilapia, Oreochromis niloticus fingerlings (4.76±0.32 g). Five iso-nitrogeneous (35% crude protein) and approximately iso-energetic (3400 ME Kcal/kg) dietsin which yellow maize was replaced by FMSat 0% (FMS0/Control diet), 25% (FMS25), 50% (FMS50), 75% (FMS75) and 100% (FMS100) levels were formulated. The fish were fed on the diets at 5% body weight for 84 days. Alkaloids were highest (2.32%) among the anti-nutritional factors analyzed in FMS, while oxalate (0.84%) was lowest. Potassium was highest (8.91 mg/g) among the minerals, while copper was lowest (0.01 mg/g). Weight gain, specific growth rate and feed conversion ratio were similar (p>0.05) in fish fed diets FMS0 and FMS50. The fish fed diet FMS0 had the highest protein efficiency ratio (1.88). Protein digestibility decreased (p<0.05) as dietary FMS increased, while carbohydrate digestibility gave an inverse relationship. Results obtained show that FMS could replace yellow maize at 50% level without affecting growth, nutrient utilization and apparent protein digestibility in diets for Nile tilapia fingerlings.

Níveis de lisina digestível em rações para alevinos de tilápia-do-nilo

Avaliaram-se níveis de lisina digestível em rações para alevinos de tilápia-do-nilo (Oreochromis niloticus), linhagem tailandesa, com base no conceito de proteína ideal. Utilizaram-se 432 alevinos com peso inicial de 0,98 ± 0,03 g, distribuídos em delineamento inteiramente casualizado, com 6 tratamentos, 6 repetições e 12 peixes por unidade experimental. Os tratamentos constaram de seis rações isoenergéticas (3.000 kcal de ED/kg de ração) e isoproteicas (39,14% de PB) contendo 1,50; 1,66; 1,82; 1,98; 2,14 ou 2,30% de lisina digestível. Foram avaliados o consumo de ração, o consumo de lisina digestível, o ganho de peso, a taxa de crescimento específico, a taxa de sobrevivência, a conversão alimentar, as taxas de deposição diária de proteína e gordura corporais, a composição química corporal (teores de umidade, proteína e gordura corporais) e a eficiência de retenção de nitrogênio. O consumo de lisina digestível, a conversão alimentar, a porcentagem de proteína corporal e a deposição de proteína corporal melhoraram de forma linear de acordo com o nível de lisina digestível. O modelo Linear Response Plateau foi o de melhor ajuste para consumo de ração, ganho de peso, taxa de crescimento específico e eficiência de retenção de nitrogênio e estimou em 2,06; 2,17; 2,14 e 2,12%, respectivamente, os níveis de lisina digestível para melhorar cada um desses parâmetros. A exigência de lisina digestível e total em rações para alevinos de tilápia-do-nilo é, respectivamente, de 2,17% (0,723%/Mcal de energia digestível) e de 2,32% (0,773%/Mcal de energia digestível) para atender às principais características de desempenho e de carcaça utilizando-se o conceito de proteína ideal na formulação das rações.

Crude protein reduction and digestible methionine+cystine and threonine to digestible lysine ratios in diets for Nile tilapia fingerlings

The objective of the present study was to investigate crude protein reduction and the methionine+cystine and threonine to lysine ratios in diets for reversed Nile tilapia fingerlings (Oreochromis niloticus), Thai strain. Four hundred and twenty Nile tilapia fingerlings with an average initial weight of 1.83 ± 0.02 g were placed in a completely randomized design, with five treatments, seven replications per treatment and 12 fish per experimental unit, for 37-days. Two crude protein (CP) levels were evaluated (32 and 28%). The diet with 32% CP had methionine+cystine:lysine and threonine:lysine ratios of 63 and 74%, respectively. Three diets with 28% CP had methionine+cystine:lysine and threonine:lysine ratios of 63 and 74%, 60 and 74% and 60 and 69%, respectively. The diet with 28% CP and had methionine+cystine:lysine ratio of 63% and threonine:lysine of 74% and was supplemented with 0.3% glutamic acid. The fish were kept in thirty-five 130 L aquariums supplied with single-pass flow-through water, individual aeration and fed ad libitum six times per day. Fish fed the diet with 32% CP had lower protein efficiency ratios and nitrogen efficiency ratios. The diet CP level was 28% and the methionine+cystine and threonine to lysine ratios were 60 and 69%, respectively.

Farinha de peixe em rações para alevinos de tilápia do Nilo, &lt;em&gt;Oreochromis niloticus&lt;/em&gt; (L.), linhagem tailandesa

Fishmeal in the diets of Nile tilapia fingerlings Oreochromis niloticus (L.), Thai strains. The adequate fishmeal (FM) inclusion level in diets for Nile tilapia fingerlings, Oreochromis niloticus (Perciformes, Cichlidae) Thai strain, is provided. Three hundred fishes with initial mean average weight of 0.42 ± 0.01 g were distributed in 25 net ponds in a randomized block design with five treatments (0, 4, 8, 16 e 20% of FM in diet) and five repetitions. Quadratic effect (p 0,05) did not affect survival and carcass yield. It may be concluded that the appropriate fishmeal inclusion is 12.15% in