RESUMO -O objetivo neste trabalho foi estudar o perfil de crescimento e a deposição de nutrientes nos órgãos (coração, fígado, moela, intestino e proventrículo) de frangos de corte das linhagens Ross e Cobb de ambos os sexos. Foram utilizados 1.920 pintos de 1 dia alojados em boxes de galpão experimental em piso. O delineamento experimental foi inteiramente casualizado, em esquema fatorial 2 × 2, composto de dois sexos (machos e fêmeas) e duas linhagens (Ross e Cobb), com quatro repetições de 120 aves. As aves foram alimentadas com rações formuladas de acordo com suas exigências nutricionais em cada fase de criação. Os pesos dos órgãos e de seus componentes (água, cinzas, proteína e gordura) foram obtidos semanalmente, com os parâmetros estimados pela equação de Gompertz e as taxas de crescimento determinadas por meio das derivadas das equações. Não houve influência da linhagem nas taxas de crescimento e deposição de nutrientes no coração. As aves Ross foram mais precoces no crescimento e na deposição de água e cinzas no fígado, portanto apresenta maior atividade metabólica na digestão e síntese de nutrientes. A linhagem Cobb foi mais precoce no desenvolvimento do intestino e crescimento e na deposição de nutrientes no proventrículo. Os machos são mais precoces que as fêmeas na taxa de crescimento e deposição de proteína, gordura e água na moela.Palavras-chave: Cobb, equações de predição, fêmeas, Gompertz, machos, Ross Growth and nutrients deposition on organs of two commercial strains of broiler chickensABSTRACT -This work was carried out with the objective of studying the growth profile and the nutrients deposition on organs (heart, liver, gizzard, intestine and proventricle) of male and female broiler chickens from Ross and Cobb lineages.It was used 1,920 chicks at the age of one day placed in experimental shed boxes on the floor. The experimental design was completely randomized in a 2 × 2 factorial model composed of 2 sexes (mates and females) and two strains with 4 repetitions of 120 broilers each. The broilers were fed formulated diets to supply the nutrient requirements according to each breeding phase. After 24 hours of fasting, the broilers were weighed and slaughtered (1 to 56 days) every week. The weight and components of the organs (water, ash, protein and fat) were weekly obtained, with parameters estimated by the equation ofGompertz and the growth rates were determined by the derived of the equations. There was no influence of the strains on the deposition of nutrients on the heart. Ross chicks were more precocious on growth and on the deposition of water and ashes in the liver, therefore it presents a greater metabolic activity in digestion and nutrient synthesis. Cobb strain was more precocious in the development of the intestine and the growth and deposition of nutrients on the proventricle. Males are more precocious than females on the growth rate and on the protein, fat and water deposition in the gizzard.

The aim of this study was to determine the requirement for lysine in the diet of juvenile tambaqui (Colossoma macropomum). In total, 750 juvenile fish (0.34 ± 0.02g) were distributed in tanks arranged in a randomized block design with six treatments, five replications in two blocks, and 25 fish per unit, for 50 d. Six levels of digestible lysine were tested (1.30, 1.48, 1.66, 1.84, 2.02, and 2.20%), in formulated diets based on the ideal protein concept. The performance, feed efficiency, daily deposition of protein and body fat, and nitrogen retention efficiency of the fish were evaluated. The consumption of rations and protein, specific growth rate, body composition, and deposition of body fat were not influenced by the lysine levels tested. The consumption of digestible lysine increased linearly and the efficiency of digestible lysine for weight gain decreased linearly with the increase in lysine levels. The levels of digestible lysine that optimized weight gain and body protein deposition were estimated at 1.73 and 1.78%, respectively. The feed conversion and nitrogen retention efficiency were most improved at 1.66% and 1.84%, respectively. The recommended level of dietary lysine for providing better weight gain and body protein deposition in juvenile tambaqui is 1.78%, equivalent to 2.00% total lysine.

RESUMO -O objetivo neste estudo foi avaliar diferentes modelos ajustados às respostas de ganho de peso obtidas em experimento com aves da linhagem ISA Label no período de 1 a 28 dias de idade. Foram utilizados 480 pintos de ambos os sexos, distribuídos em delineamento inteiramente casualizado, em arranjo fatorial 4 × 2 (níveis de lisina × sexo), com três repetições, com 20 aves por unidade experimental. Uma ração basal foi formulada para atender às exigências das aves, exceto em lisina. Essa ração foi suplementada com L-lisina HCl em substituição ao ácido L-glutâmico, resultando em rações experimentais isonitrogênicas e isoenergéticas contendo 0,85; 0,97; 1,09 e 1,21% de lisina digestível. As respostas de ganho de peso foram ajustadas de acordo com os níveis de lisina da ração pelos modelos Linear Reponse Plateau (LRP), segmentado de duas inclinações, polinomial quadrático e exponencial. A primeira intersecção da equação quadrática com o platô do LRP também foi utilizado para estimar o nível ótimo. Os níveis de lisina digestível estimados pelos modelos LRP, segmentado e quadrático, foram 0,999; 1,010 e 1,116%, respectivamente. Na combinação do modelo quadrático com o LRP, a estimativa da exigência de lisina digestível foi de 1,041%. O modelo exponencial proporcionou estimativa de 1,066%, considerando 95% da resposta assintótica. Com base nos custos com alimentação, esse mesmo modelo gerou estimativas de 1,000 e 1,030% quando o custo do quilograma de L-lisina HCl foi R$ 8,50 e R$ 6,50, respectivamente. Considerando as limitações de cada um dos modelos propostos, o procedimento para estimar as exigências de lisina digestível pela primeira intersecção da equação quadrática com o platô do LRP foi o mais adequado para melhorar o ganho de peso das aves quando variáveis econômicas não foram consideradas.Palavras-chave: aminoácidos digestíveis, dose-resposta, frangos de corte, modelos de regressão Mathematical models to estimate digestible lysine of ISA Label broilersABSTRACT -The objective of this study was to evaluate different models in the adjustment of weight gain (WG) responses, obtained in an experiment carried out with ISA Label birds from 1 to 28 days of age. A total of 480 male and female chicks were distributed in a completely randomized design, in a 4 × 2 factorial arrangement (lysine levels × sex), with three replications of 20 birds each. The basal diet was formulated to meet the chick requirements, except for lysine.This diet was supplemented with L-lysine HCl replacing the L-glutamic acid and resulting in experimental diets containing 0.85, 0.97, 1.09 and 1.21% digestible lysine. The weight gain response was adjusted to lysine levels according to following models: Linear Response Plateau (LRP), segmented regression with two slopes, quadratic and exponential. The first interception of the quadratic model on the LRP plateau was used to estimate the optimum lysine level. The lysine levels estimated according to LRP, segmented regression and quadratic models were 0.999, 1.010 and 1.116%, respectively. The di...

No abstract

-Tambaqui is intensively farmed because of its production characteristics; however, there is a lack of information lacks about the nutritional requirements of this species. The present study aimed to evaluate the effects of various crude protein (CP) levels in the diets of tambaqui fingerlings. A total of 750 fingerlings with an initial weight of 0.35 ± 0.09 g were selected in a completely randomized design with six treatments (experimental feeds with 20%, 24%, 28%, 32%, 36%, and 40% CP), five replicates, and 25 fish per experimental unit. Performance, survival rate, carcass yield, body composition, protein deposition, body fat, and nitrogen retention efficiency were evaluated after 45 days. CP levels did not affect the following: feed conversion, survival rate, moisture content, and carcass yield. However, with increasing CP levels, protein efficiency ratio decreased. Weight gain, feed conversion, and specific growth rate improved until CP levels of 31.57%, 28.90%, and 31.12%, respectively, were achieved. Quadratic effects of elevated CP levels on body fat and body fat deposition were observed at minimum CP levels of 26.55% and 23.77%, respectively; and on body protein, body protein deposition, and nitrogen retention efficiency at maximum CP levels of 29.26%, 32.50%, and 27.21%, respectively. We conclude that a CP level of 31.57% is recommended for the diets of tambaqui fingerlings weighing between 0.35 and 15.11 g, which corresponds to a digestible energy:CP ratio of 9.50 kcal DE/g CP. Keywords:Performance. Initial phase. Protein nutrition. PROTEÍNA BRUTA EM DIETAS PARA ALEVINOS DE TAMBAQUI, COLOSSOMA MACROPOMUM (Cuvier, 1818)RESUMO -O tambaqui é utilizado intensamente na piscicultura em virtude de suas características produtivas, porém há carência de informações sobre suas exigências nutricionais. Objetivou-se avaliar os efeitos de níveis de proteína bruta (PB) em dietas para alevinos de tambaqui. Utilizou-se 750 alevinos com peso inicial de 0,35 ± 0,09 g, em delineamento inteiramente casualizado, com seis tratamentos (rações experimentais com 20, 24, 28, 32, 36 e 40% de PB), cinco repetições e 25 peixes por unidade experimental. Avaliou-se desempenho, taxa de sobrevivência, rendimento de carcaça, composição corporal, deposição de proteína e gordura corporais e eficiência de retenção de nitrogênio, após o período de 45 dias. Os níveis de PB não influenciaram: consumo de ração, taxa de sobrevivência, umidade corporal e rendimento de carcaça. O consumo de PB aumentou e a taxa de eficiência proteica reduziu com a elevação dos níveis de PB. O ganho de peso, a conversão alimentar e a taxa de crescimento específico melhoraram até o nível de 31,57; 28,90 e 31,12% de PB, respectivamente. Observou-se efeito quadrático da elevação dos níveis de PB sobre a gordura corporal, deposição de gordura corporal, proteína corporal, deposição de proteína corporal e eficiência de retenção de nitrogênio, apresentando nível mínimo em 26,55; 23,77% de PB; e nível máximo em 29,26; 32,50; 27,21% de PB, respectivamente. Conclui...

The objective of this study was to determine the optimal digestible threonine to lysine ratios in diets of tambaqui (Colossoma macropomum) juveniles. Five-hundred fish with a mean ± SE initial weight of 2.16 ± 0.03 g were used in a completely randomized design, consisting of four treatments, five replicates per treatment, and 25 fish per experimental unit. The treatments consisted of four isoenergetic, isophosphoric, isocalcic, and isolisinic (1.45%) diets, consisting of a basal diet supplemented with four L-threonine levels (1.013, 1.085, 1.158, and 1.230%), resulting in different threonine to lysine ratios (70, 75, 80, and 85%). Fish were maintained in twenty 500-L aquaria with independent water supply, drainage, and aeration systems, and were fed to apparent satiation six times a day for 45 days. Performance, feed efficiency, daily protein and fat deposition, body moisture content, and nitrogen retention efficiency of fish were evaluated. The digestible threonine intake increased linearly, and the efficiency of threonine for weight gain decreased quadratically, with increasing digestible threonine to lysine ratios. Weight gain, specific growth rate, feed:gain ratio, protein efficiency for weight gain, and nitrogen retention efficiency of fish increased in a quadratic manner with increasing digestible threonine to lysine ratios up to the levels of 75.96, 76.06, 76.36, 76.47, and 74.02%, respectively. It was concluded that the digestible threonine to lysine ratio for use in diets of juvenile tambaqui to achieve optimal performance and nitrogen retention efficiency is 76 and 74%, respectively, which corresponds to a digestible threonine level of 1.102 and 1.073%.

No abstract

The aim of this work was to compare the efficiency of total (TC) or partial (PC) collection excreta methods to determine metabolizable energy in poultry feeds. A number of 180 12- to 21-day-old broilers were distributed into two treatments of six replicates of 10 birds each. A reference-diet was formulated to supply broiler requirements, and the test-diets consisted of 60% of reference diets and 40% of corn or soybean meal. Celite was added at 1% to the diets as a marker. Excreta and diet samples were analyzed for dry matter, energy, nitrogen, and acid-insoluble ash (AIA). AME of corn determined by partial collection (PC) was higher (3544 kcal/kg) as compared to total collection (TC) (3133 kcal/kg). However, no difference were observed for soybean meal (1797 vs. 1821 kcal/kg) between both methods. Marker recovery rates in the excreta were 101, 111, and 96% for the basal-diet, and the test-diets with corn or soybean meal, respectively. This result indicates the importance of marker recovery rate in the excreta to evaluate feed AME and digestibility