Marcos Antonio Delmondes Bomfim

Proteína bruta e energia digestível em dietas para alevinos de curimbatá (Prochilodus affins)

Two hundred and fifty six curimbata (Prochilodus affins) fingerlings averaging initial weight of 2.72 ± 0.11 g, stocked in 32 aquariums (100 L) with water renewal, controlled temperature and individual aeration, were used to determine the dietary crude protein (CP) requirements, according to the digestible energy level (DE). The experiment was carried out in to a 4 x 2 factorial scheme (four CP levels: 18.0, 22.0, 26.0 and 30.0% combined with two DE levels: 2,700 and 3,000 kcal/kg), according to a completely randomized design with four replicates of eight fishes. The fishes were fed ad libitum twice a day, during 78 days. Weight gain, apparent feed intake, apparent feed:gain ratio, specific growth rate, protein efficiency rate, nitrogen retention efficiency, humidity, body fat and protein, nitrogen and fat percentage in weight gain were evaluated. No CP ´ DE levels interaction was observed for any studied variable, except for the fat percentage in weight gain. Fishes fed diets with 3,000 kcal de DE/kg showed higher levels of dry matter, body fat and fat percentage in weight gain. It was concluded that CP and DE requirements for curimbata fingerlings are of 26.05% and 2,700 kcal/kg, respectively, that correspond to DE:CP ratio of 10.36 kcal DE/g CP, due to the best results of weight gain and carcass composition.

Níveis de energia digestível e proteína bruta em rações para alevinos de lambari tambiú

Six hundred lambari tambiu (Astyanax bimaculatus) averaging initial weight of 1.30 ± 0.01 g, placed in 40 aquariums (100 L) with water renewal, controlled temperature and individual aeration, were used to determine the digestible energy (DE) requirements, according to the dietary crude protein (CP) levels. The experiment was analyzed as a 5 x 2 factorial scheme (five levels of DE: 2,900, 3,000, 3,100, 3,200, and 3,300 kcal/kg, combined with two levels of CP: 32 and 38%), in a completely randomized design with four replicates and fifteen fishes per experimental unit. The fish were submitted to the feeding controlled based on the average daily intake of the treatments with the highest energy level (3,300 kcal/kg) for each daily corrected protein level, during 49 days. Weight gain, specific growth rate, feed intake, crude protein intake, digestible energy intake, apparent feed:gain ratio, protein efficiency rate, carcass yield, nitrogen retention efficiency, and contents of body humidity, fat and protein were evaluated. Fishes fed diets with 32% of CP showed smaller specific growth rate and protein efficiency rate and higher feed:gain ratio. Fishes fed diets with 38% of CP showed greater carcass yield. The requirement of digestible energy for lambari tambiu is of 2,900 kcal/kg for diets with 32 and 38% of CP.

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%.

Digestibilidade aparente e trânsito gastrintestinal em tilápia do Nilo (Oreochromis niloticus), em função da fibra bruta da dieta

The objective of this study was to evaluate, in purified diets, the effects of different levels of crude fiber on the apparent digestibility and gastrointestinal transit rate in Nile Tilapia. Five circular fishbowls (250 L) with a closed system of water filtering, replenishment and heat for feeding and five digestibility fishbowls with individual filtering replenishment and heat system were used. Thirty-two fishes, averaging initial weight of 30.65 ± 0.50 were used. A completely randomized design with five levels of crude fiber (2.5, 5.0, 7.5, 10.0, and 12.5%) and five replicates was used. It was concluded that increasing levels of crude fiber in purified diets significantly affect the apparent digestibility of dry matter, crude protein and ether extract. Levels up to 5.0% crude fiber did not reduce the apparent digestibility of dry matter and crude protein and levels up to 7.5% crude fiber did not reduce the apparent digestibility of ether extract of purified diet in Nile tilapia. However, the increase of dietary crude protein significantly reduce the gastrointestinal transit rate.

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.

True and apparent digestibility of protein and amino acids of feed in Nile tilapia

It was determined in this work the coefficients of apparent and true digestibility of protein and amino acids of five feeds (corn, wheat bran, soybean meal, corn gluten meal, fish meal) in Nile tilapia. It was used 252 reverted Thai strain Nile tilapia (Oreochromis niloticus) in growth phase, with weight of 310 ± 9.68 g, distributed in experimental randomized blocks design, with five treatments, six replicates per treatment and seven fish per experimental unit. Each experimental diet contained a single source of protein, composed by the studied ingredients. An additional group of fish was fed protein-free diet for quantification of the endogenous fraction and determination of true digestibility coefficients. Digestibility was estimated by the indirect method by using chromium oxide at the concentration of 0.50% of the diet as a marker, performing fecal collection at every four hour interval by using decantation technique. Coefficients of apparent digestibility of the protein and amino acids are: corn, 83.57 and 82.45%; wheat bran 82.87 and 81.47%; soybean meal 91.12 and 89.41%; corn gluten meal 90.07 and 87.78%; fish meal 83.53 and 81.65% respectively. Coefficients of true digestibility of protein and the mean of the amino acids are: corn, 90.02 and 89.60%; wheat bran 89.62 and 89.14%; soybean meal 93.58 and 91.88%; corn gluten meal 92.50 and 90.34%; fish meal 86.01 and 84.27%, respectively.

Exigência de metionina mais cistina, com base no conceito de proteína ideal, em rações para alevinos de tilápia-do-nilo

Three hundred and ninety six reverted Nile tilapia (Oreochromis niloticus), from Thailand strain, averaging initial weight of 0.86 ± 0.02 g were used to evaluate the effect of feeding methionine plus cystine:lysine levels, based on the ideal protein concept, with deficient levels of digestible lysine (1.40%). The experiment was analyzed as a completely randomized design, with six treatments, six replications by treatment and 11 fishes for experimental unit. The treatments consisted of five diets with different ratios of digestible methionine + cystine:lysine (59.5, 63.5, 67.5, 71.5 and 75.5%) and digestible threonine:lysine ratio of 80.0%; and one diet with the digestible methionine plus cystine:lysine ratio of 75.5% and threonine: digestible lysine ratio of 85.0%, all isoenitrogenous and isoprotein. The fishes were fed ad libitum six daily meals during 40 days. Performance parameters, body composition, body protein and fat deposition and nitrogen retention efficiency were evaluated. The increasing dietary digestible methionine plus cystine:lysine ratio did not affect the studied parameters, except for the body fat and humidity content, that showed quadratic effect, with quadratic maximum and minimum at 67.0 and 66.7%, respectively. However, it was observed treatment effect (75.5%) on feed:gain ratio, nitrogen retention efficiency and protein and lysine efficiency for growth. It was concluded that the total or digestible dietary sulfur amino acid level of 0.91 and 0.86%, that correspond to a total and digestible methionine plus cystine:lysine ratio of 57.2 and 59.5%, respectively, provided the best results of performance and carcass characteristics of Nile tilapia fingerlings.

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.