Moisés Quadros

Níveis de fósforo total em dietas para alevinos de tilápia-do-nilo

Four hundred and thirty-two Nile tilapia (Oreochromis niloticus) fingerlings averaging initial weight of 0.60 ± 0.02 g were allotted to thirty-six 150 L-aquaria to determine total phosphorus requirement. The experiment was analyzed as a completely randomized design, with six treatments (0.55, 0.73, 0.94, 1.14, 1.37, and 1.59% of total phosphorus), six replicates and 12 fishes per experimental unit. The fishes were fed diets with 32% of CP and 3,000 kcal of DE/kg, during 40 days. Quadratic effect was observed for feed/gain ratio and protein efficiency rate and the best results were estimated with 1.10% of total phosphorus, for both variables. Linear effect of the dietary phosphorus levels on P retention efficiency rate and P efficiency rate was noticed. No treatment effect on the other variables was observed. The dietary total phosphorus requirement for Nile tilapia corresponds to 1.10%.

Níveis de lisina, com base no conceito de proteína ideal, em rações para alevinos de tilápia-do-nilo

The effects of the digestible lysine level were assessed in feeds for Nile tilapia fingerlings (Oreochromis niloticus), based on the ideal protein concept. Four hundred and thirty two reverted fingerlings were used, average weight 1.12 ± 0.02 g, in a randomized complete design, consisting of 6 feeds, six replications and twelve fish per experimental unit. The diets consisted of a basal diet with 29.12% crude protein and 3,000 kcal/kg digestible energy, supplemented with synthetic amino acids, resulting in six diets with 0.95; 1.10; 1.25; 1.40; 1.55 and 1.70% digestible lysine and minimum ratios between methionine plus cystine, threonine, thryptophan, isoleucine, arginine with the lysine (66, 77, 23, 64 and 85%, respectively), based on digestible values. The fish were maintained in 130 liter aquaria equipped with individual water and controlled temperature and aeration. The fish were fed to apparent satiation, six times a day, for 30 days. Growth performance, body composition, body protein and fat deposition and nitrogen retention efficiency of the fish were evaluated. The increase in the dietary digestible lysine did not affect the survival rate and body fat level of the fishes. However, there was linear improvement in all the other parameters assessed, except lysine use efficiency and the body humidity, that showed quadratic and lineardecline, respectively. The levels of 1.80 (0.600% Mcal of DE) total lysine and 1.70% (0.567% Mcal of DE) digestible lysine, respectively, result in the best performance and carcass characteristics of Nile tilapia fingerlings, when the ideal protein concept is used to formulate the experimental diets.Avaliaram-se os efeitos dos niveis de lisina digestivel da racao, com base no conceito de proteina ideal, no desempenho de alevinos de de tilapia-do-nilo (Oreochromis niloticus). Utilizaram-se 432 alevinos revertidos, linhagem tailandesa, com peso inicial de 1,12 ± 0,02 g, em delineamento inteiramente ao acaso, composto de 6 dietas, 6 repeticoes e 12 peixes por unidade experimental. Como tratamentos, avaliaram-se uma dieta basal com 29,12% de proteina bruta e 3.000 kcal de energia digestivel/kg, suplementada com aminoacidos sinteticos, resultando em dietas com 0,95; 1,10; 1,25; 1,40; 1,55 e 1,70% de lisina digestivel e relacoes minimas entre metionina + cistina, treonina, triptofano, isoleucina e arginina com a lisina (66, 77, 23, 64 e 85%, respectivamente), com base em valores digestiveis. Os peixes foram mantidos em aquarios de 130 litros, dotados de abastecimento de agua, temperatura controlada e aeracao individual, e alimentados a vontade em seis refeicoes diarias durante 30 dias. Avaliaram-se os parâmetros de desempenho, a composicao corporal, a deposicao de proteina e gordura corporais e a eficiencia de retencao de nitrogenio dos peixes. A elevacao do teor de lisina digestivel na racao nao influenciou a taxa de sobrevivencia e o teor de gordura corporal dos peixes, mas melhorou de forma linear todos os demais parâmetros avaliados, com excecao da eficiencia de utilizacao de lisina e a umidade corporal, que pioraram de forma quadratica e linear, respectivamente. O nivel de 1,80% de lisina total (0,600% Mcal de ED) e o de 1,70% de lisina digestivel (0,567% Mcal de ED) proporcionam os melhores resultados de desempenho e caracteristicas de carcaca de alevinos de tilapia-do-nilo quando se utiliza o conceito de proteina ideal na formulacao das racoes experimentais.

Redução de proteína bruta com suplementação de aminoácidos, com base no conceito de proteína ideal, em rações para alevinos de tilápia-do-nilo

The effect of decreasing dietary crude protein (CP) with supplementation of amino acids, based on the ideal protein concept on Nile tilapia (Oreochromis niloticus) fingerlings performance was evaluated. A total of 396 fingerlings from Thai strain, with 0.80 ± 0.17 g of BW, was allotted to a randomized block design, with six levels of CP (32, 31, 30, 29, 28 and 27% of CP) in the diets, six replications with 11 fish each. The diets were formulated to be isocaloric and digestible isolysine, remaining constant the amino acids to lysine minimum ratio. The fish were kept in 36 aquariums of 130 L, equipped with water supply, controlled temperature and individual aeration, and ad libitum fed six times a day for 40 days. The reduction of CP content of the diet did not affect weight gain, specific growth rate, feed intake, digestible lysine intake, body protein content, fat and protein deposition rates and nitrogen retention efficiency of fishes. The fish fed diets with 27% of CP lower feed: gain ratio, lysine efficiency for gain, nitrogen intake and body water and higher protein efficiency for gain and body fat content. The level of crude protein of the diet for Nile tilapia fingerlings can be reduced by four percentage points (from 32 to 28%), without negative effect on the performance of the animals, since the diets are supplemented with essential limiting amino acids.

Níveis de proteína bruta em dietas para alevinos de acará-bandeira

The aim of this experiment was to evaluate dietary protein requirements of freshwater angelfish fry. A complete randomized design with four dietary crude protein levels (34, 38, 42, and 46% of CP) and four replicates was used. Fish averaging 0.44±0.05 g were reared in sixteen 25L-aquarium with aeration, biological filter and controlled temperature (26 ± 0.5°C), in a stocking density of six fish/aquarium. Fish were fed ad libitum at 8:00 a.m., 11:00 a.m., 2:00 p.m, and 5:00 p.m, during 60 days. Final weight, weight gain, feed intake, feed:gain ratio, specific growth rate and protein efficiency ratio (PER) were the evaluated parameters of productive performance. At the end of the experiment, no treatment effect on productive performance, with the exception of PER was observed. Fishes fed diets with 46% CP showed PER significant smaller than those fed diets with 34 and 38% of CP. PER of fish fed diets with 42% of CP did not differ from the other treatments. Diets with 34% of CP can meet the protein nutritional requirements of freshwater angelfish fry.

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

The effect of digestible lysine levels was evaluated in diets for Nile tilapia fingerlings (Oreochromis niloticus), Thailand lineage, based on the ideal protein concept. Four hundred and thirty two Nile tilapia fingerlings with an initial body weight of 0.98 ± 0.03 g were allotted in a randomized complete design, with six treatments, six replications per treatment and twelve fish per experimental unit. The treatments consisted of six isoenergetic (3.000 kcal of DE/kg feed) and isoproteic (39.14% CP) diets with different levels of digestible lysine (1.50, 1.66, 1.82, 1.98, 2.14 and 2.30%). Feed intake, digestible lysine intake, average weight gain, specific growth rate, survival rate, feed conversion, daily protein deposition rate, daily fat deposition rate, chemical body composition (moisture, protein and fat content) and nitrogen retention efficiency were evaluated. The different levels of lysine improved linearly the parameters of digestible lysine intake, feed conversion, body protein content and body protein deposition. The Linear Response Plateau model best fitted the parameters of feed consumption, average weight gain, specific growth rate and nitrogen retention efficiency, estimating at 2.06%, 2.17, 2.14 and 2.12% respectively, the level of digestible lysine to maximize each of the parameters. The digestible and total digestible lysine requirement for Nile tilapia fingerlings was 2.17% (0.723%/Mcal of DE) and 2.32% (0.773%/Mcal of DE), respectively, to meet the main performance parameters and carcass traits, when the ideal protein concept was used in diet formulation.

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

Objetivou-se avaliar a reducao do nivel de proteina bruta e as relacoes dos aminoacidos metionina+cistina e treonina digestiveis com a lisina digestivel em dietas para alevinos revertidos de tilapia-do-nilo (Oreochromis niloticus), da linhagem tailandesa. Um experimento com duracao de 37 dias foi realizado utilizando-se 420 alevinos com peso inicial de 1,83 ± 0,02 g, distribuidos em delineamento inteiramente ao acaso, composto de 5 dietas, 7 repeticoes e 12 peixes por unidade experimental. Foram avaliados dois niveis de PB (32 e 28%) em diversas dietas experimentais. Na dieta com 32% de PB, foram mantidas as relacoes de metionina+cistina e treonina com lisina de 63 e 74%, respectivamente; nas tres dietas com 28% de PB, as relacoes de metionina+cistina e treonina com lisina foram de 63 e 74%, 60 e 74% e 60 e 69%, respectivamente; e, na dieta com 28% de PB, as relacoes de metionina+cistina e treonina com lisina foram de 63 e 74%, respectivamente, porem com acrescimo de 0,3% de acido glutâmico. Os peixes foram mantidos em 35 aquarios de 130 litros, com abastecimento de agua, aeracao individual e alimentacao a vontade em seis refeicoes diarias. Os peixes mantidos com a dieta com 32% de PB apresentaram menores eficiencias de retencao de proteina e de nitrogenio. O nivel de PB de racoes para alevinos de tilapia-do-nilo deve ser de 28,0% e as relacoes de metionina+cistina digestivel e treonina digestivel com a lisina, de 60 e 69%, respectivamente.

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

The effects of digestible threonine levels, based on ideal protein concept in diets with 1.35% of digestible lysine on Nile tilapia (Oreochromis niloticus) fingerlings performance. Four hundred thirty two reverted Nile tilapia, Thailand strain, with initial weight of 1.64 ± 0.03 g, were allotted to completely randomized design, with six diets and six replications with twelve fishes each. The five diets, isoenergetic isoproteic, consisted of various threonine:digestible lysine ratio (69.0, 74.0, 79.0, 84.0, and 89.0%) and methionine + cystine:digestible lysine ratio of 70.0% and one diet with threonine:digestible lysine of 84.0% and methionine + cystine:digestible lysine of 75.0%. The fish were kept in 36 aquariums of 130 L, equipped with water supply, controlled temperature and individual aeration, and ad libitum fed six times a day for 30 days. Performance, body composition, protein and fat depositions and nitrogen retention efficiency of fishes were evaluated. Consumption of feed, body protein content and body protein deposition increased in a linear fashion in accordance to threonine:digestible lysine in the diet, however, was not affected by the increase of dietary methionine + cystine:digestible lysine. Total or digestible threonine levels that provided the best results of performance of Nile tilapia fingerlings were 1.11 and 0.99%, while the levels that promoted better body protein deposition were 1.43 and 1.28%, which correspond to threonine:total lysine ratio of 71.0 and 69.0% and threonine:digestible lysine of 90.0 and 89.0%.

Apparent and true digestibility of protein and amino acid in feedstuffs used in Nile Tilapia feed as determined by the technique of dissection

The objective of this study was to determine the coefficients of apparent and true digestibility of protein and amino acids of five feedstuffs (corn, wheat bran, soybean meal, corn gluten meal and fish meal) in 900 sex-reversed Nile tilapia (Oreochromis niloticus) of the Thai strain during the growth phase, with an initial weight of 315±8.45 g. A total of 750 fish were distributed according to a randomized block design (repetitions in time) into five treatments with six replicates of 25 fish each. The remaining 150 fish were fed a protein-free diet to measure endogenous protein and amino acid losses in order to determine the true digestibility of these components. Each tested diet contained a single protein source, which consisted of one of the evaluated feedstuffs. Digestibility was indirectly estimated using chromic oxide at 0.50% as marker. Digesta was collected from the last 5 cm of the distal intestine (between the ileal-rectal valve and the anus) using the dissection technique. Apparent digestibility coefficients of protein and amino acids were, on average, 74.69 and 73.62% for corn, 73.74 and 72.81% for wheat bran, 86.01 and 84.66% for soybean meal, 85.19 and 84.29% for corn gluten meal, 76.74 and 75.56% for fish meal, respectively. True digestibility coefficients of protein and amino acids were, on average, 85.21 and 83.97% for corn, 84.41 and 83.74% for wheat bran, 87.22 and 87.51% for soybean meal, 87.97 and 87.34% for corn gluten meal, and finally 79.58 and 78.44% for fish meal, respectively.

Fertilizers for Daphnia sp. (Crustacea, Cladocera) production in experimental tanks

The current study was aimed at investigating the use of different fertilizers - dicalcium phosphate, biosolid and quail feces - as a strategy for water fertilization in Daphnia sp production. It was used twenty-four 100-L tanks of asbestos cement distributed in a completely randomized split-plot design with six replicates, with plots in the three kinds of fertilizers (biosolid, dicalcium phosphate, and quail feces) and a control without fertilization (WF) and subplots at the times of assessment (days 8 and 13). It was assessed the biomass production of Daphnia sp. and the following water quality parameters: chlorophyll a, electrical conductivity, pH, dissolved oxygen, temperature, ammonia and organic nitrogen, total phosphorus and total hardness. There was a significant correlation between the values of chlorophyll a and biomass weight of Daphnia sp, which indicates interactions between phytoplankton and zooplankton communities. The maximum weight of Daphnia sp. biomass is found in tanks fertilized with quail feces (35.98 g), followed by the biosolid (16.80 g), control without fertilization (6.75 g) and dicalcium phosphate (5.24 g).