Broiler responses to copper levels and sources: growth, tissue mineral content, antioxidant status and mRNA expression of genes involved in lipid and protein metabolism.

BACKGROUND: Five hundred 8-d old male broilers Cobb500 were randomly allotted into 10 treatments in factorial arrangement with 5 Cu levels (0, 4, 8, 12, and 16 mg/kg), and 2 sources (Cu proteinate, CuPro and Cu sulphate, CuSO4.5H2O) for a 10-d-experiment. RESULTS: Feed conversion ratio (FCR) was better (P < 0.05) in CuPro fed chicks compared with CuSO4.5H2O group. Average daily feed intake (ADFI) decreased linearly (P < 0.05) as dietary Cu increased. A quadratic response (P < 0.05) to Cu levels was found for FCR, being optimized at 9.87 and 8.84 mg Cu/kg in CuPro and CuSO4.5H2O diets, respectively. Copper supplementation linearly increased liver Cu content (P < 0.05) and tended to linearly increase (P = 0.07) phosphorus (P) and copper in tibia. Manganese and zinc were higher (P < 0.05) in tibia of CuPro fed birds. Broilers fed CuPro exhibited lower liver iron (P < 0.05) content, lower activities of Cu, Zn superoxide dismutase (CuZnSOD) in breast muscle and liver, and glutathione peroxidase in liver. Glutathione peroxidase reduced linearly (P < 0.05) with CuPro levels and increased linearly (P < 0.05) with CuSO4.5H2O levels and were lower (P < 0.05) in all CuPro levels in breast muscle. Breast muscle malondialdehyde concentration tended to be higher (P = 0.08) in broilers fed CuSO4.5H2O. Copper levels linearly increased (P < 0.05) metallothionein (MT) and malate dehydrogenase (MDH) expression in liver, and six-transmembrane epithelial antigen of the prostate-1 (STEAP-1) in the intestine. Copper elicited a quadratic response (P < 0.050) in AKT-1 and mammalian target of rapamycin (mTOR) in breast muscle, CuZnSOD in liver and antioxidant 1 copper chaperone (ATOX 1) in intestine. Broilers fed CuPro exhibited higher mRNA expression of mTOR in muscle breast and lower CuZnSOD in liver and ATOX 1 in intestine. Interaction (P < 0.05) between levels and sources was found in mRNA expression for GSK-3ß, MT, and CuZnSOD in breast muscle, FAS and LPL in liver and MT and CTR1 in intestine. CONCLUSIONS: CuPro showed beneficial effects on feed conversion and bone mineralization. Organic and inorganic Cu requirements are 9.87 and 8.84 mg Cu/kg, respectively.

Selenium source and level on performance, selenium retention and biochemical responses of young broiler chicks.

BACKGROUND: Selenium (Se) has been recognized as an essential micronutrient for nearly all forms of life. In recent decades, broiler responses to dietary Se supplemental levels and sources have received considerable attention. On environmental grounds, organic trace mineral utilization in practical broiler feeds has been defended due to its higher bioavailability. In such feeds, trace minerals are provided simultaneously in the same supplement as inorganic salts or organic chelates, a fact commonly ignored in assays conducted to validate organic trace mineral sources. The current assay aimed to investigate growth and biochemical responses, as well as Se retention of growing chicks fed diets supplemented with organic and inorganic Se levels and where the trace minerals (zinc, copper, manganese, and iron) were provided as organic chelates or inorganic salts according to Se source assessed. In so doing, a 2 × 5 factorial arrangement was used to investigate the effects of sodium selenite (SS) and selenium-yeast (SY) supplemented in feeds to provide the levels of 0, 0.08, 0.16, 0.24, and 0.32 mg Se/kg. RESULTS: Chicks fed selenium-yeast diets had body weight (BW), and average daily gain (ADG) maximized at 0.133 and 0.130 mg Se/kg, respectively. Both Se sources linearly increased (P < 0.05) the glutathione peroxidase (GSH-Px) activity in chick blood but higher values were observed in sodium selenite fed chicks (P < 0.05). Both Se sources influenced thyroid hormone serum concentrations (P < 0.05). Chicks fed SY exhibited greater retention of Se in the feathers (P < 0.05). Relative bioavailability of selenium yeast compared with SS for the Se content in carcass, feathers, total and Se retention were, 126, 116, 125 and 125%, respectively. SY supplementation resulted in lower liver Se concentration as Se supplementation increased (P < 0.05). CONCLUSIONS: Based on performance traits, the supplemental level of organic Se as SY in organic trace minerals supplement to support the maximal growth of broiler chicks is 0.133 mg Se/kg.

Response of broilers to digestible sulfur amino acids and threonine intake: Maximum economic return / Respuesta de pollos de engorde a la ingesta de aminoácidos azufrados y treonina digestibles: máximo retorno económico / Resposta de frangos de corte ao consumo de aminoácidos sulfurados e treonina digestíveis: máximo retorno econômico

Abstract Background: The determination of amino acid supplements for broiler chicken requirements based on performance does not always reflect maximum profitability. Objective: To estimate the optimal levels of digestible threonine (Thr) and sulfur amino acids (SAA) in diets for broilers based on an economic analysis. Methods: Two dose-response assays were conducted, and each assay was divided into three phases: initial (1-14 days), grower (15-28 days), and finisher (29-42 days). Five hundred and sixty male Cobb 500® broilers were randomly distributed to seven treatments with increasing levels of the amino acid (SAA or Thr), with four replicates and 20 birds each. Bodyweight gain (BWG) and feed intake (FI) were used to fit a segmented model. Gross income (GI), total feed costs (TFC) and gross margin (GM) were calculated based on local values. Results: Increasing levels of amino acid elicited a response in BWG and FI for all evaluated phases. The estimates for maximum profit based on GI and TFC were 223, 504, and 975 mg SAA/bird/d, and 236, 696, and 1,042 mg Thr/bird/d in starter, grower and finisher phases, respectively. Conclusion: Varying the AA prices affected only slightly the economic optimal intake of Thr and sulfur amino acids. Despite market fluctuations, the economic approach presented in this study demonstrates to be a helpful tool to choose the ideal inclusion level of amino acids in the feed.

Resumen Antecedentes: La determinación de la suplementación de aminoácidos en las dietas de pollos de engorde, basados solamente en el desempeño productivo no siempre refleja la máxima rentabilidad. Objetivo: Estimar los niveles óptimos de treonina (Thr) y aminoácidos azufrados (SAA) en dietas para pollos de engorde basados en un análisis económico. Métodos: Se realizaron dos ensayos tipo dosis-respuesta divididos en tres fases cada uno: inicio (1-14 días), crecimiento (15-28 días) y finalización (29-42 días). Quinientos sesenta pollos de engorde machos Cobb 500® se distribuyeron aleatoriamente en siete tratamientos con niveles crecientes de aminoácidos (SAA o Thr) y cuatro repeticiones de 20 aves cada uno. La ganancia de peso (BWG) y el consumo de alimento (FI) fueron utilizados para ajustar un modelo segmentado. El ingreso bruto (GI), costo total de la ración (TFC) y el margen bruto (GM) se calcularon tomando como referencia valores locales. Resultados: Los niveles crecientes de aminoácidos influyeron en la respuesta de BWG y FI en todas las fases evaluadas. Los estimados para maximizar la rentabilidad según GI y TFC fueron 223, 504 y 975 mg SAA/ave/día, y 236, 696 y 1,042 mg Thr/ave/día para las fases de inicio, crecimiento y finalización, respectivamente. Conclusión: La variación de los precios de los AA tuvo solo un ligero efecto sobre el consumo óptimo de Thr y aminoácidos azufrados. A pesar de las fluctuaciones del mercado, el enfoque económico aquí expuesto demuestra ser una herramienta útil para la elección del nivel ideal de inclusión de aminoácidos en la formulación.

Resumo Antecedentes: A determinação da suplementação de aminoácidos em frangos de corte baseados somente no desempenho produtivo nem sempre reflete a rentabilidade máxima. Objetivo: Estimar os níveis ótimos de treonina (Thr) e aminoácidos sulfurados (SAA) em dietas para frangos de corte com base em uma análise econômica. Métodos: Foram realizados dois ensaios dose-resposta, divididos em três fases cada: inicial (1-14 dias), crescimento (15-28 dias) e final (29-42 dias). Quinhentos e sessenta frangos de corte machos Cobb 500® foram distribuídos aleatoriamente em sete tratamentos, representados por níveis crescentes de aminoácidos (SAA ou Thr), com quatro repetições de 20 aves cada. O ganho de peso (BWG) e o consumo de ração (FI) foram utilizados para ajustar um modelo segmentado. A receita bruta (GI), os custos totais de alimentação (TFC) e a margem bruta (GM) foram calculados com base nos custos locais. Resultados: Os níveis dos aminoácidos influenciaram as respostas de BWG e FI para todas as fases avaliadas. A estimativa para máximo lucro com base em GI e TFC para os ensaios com SAA foram 223, 504 e 975 mg/ave/d; para Thr foram 236, 696 e 1,042 mg/ave/d para as fases inicial, crescimento e final, respectivamente. Conclusão: A variação dos preços dos AA teve pouca influência sobre a ingestão econômica dos aminoácidos sulfurados e da Thr. Apesar do dinamismo de mercado, a abordagem econômica apresentada neste estudo demonstra ser uma ferramenta útil para a escolha do nível de inclusão ideal do aminoácido na ração.

Relação treonina: lisina digestíveis na dieta de poedeiras leves de 42 a 58 semanas de idade

SUMMARY This study was conducted to determine the ideal ratio of digestible threonine: lysine in diets for laying hens at 42 to 58 weeks of age. Two hundred forty Hy Line W-36 laying hens were used at 42 weeks of age for 16 weeks. The treatments were distributed in a completely randomized design with eight replicates and six birds each. The experimental diets were formulated with five levels of digestible threonine (0.461; 0.515; 0.569; 0.622 and 0.676%) providing the five ratio of digestible threonine: lysine (60; 67; 74; 81 and 88%) studied. The variables analyzed were: egg production; feed intake; lysine intake; threonine intake; mass egg; average egg weight; lysine use efficiencies by mass and produced eggs; feed conversion per mass and dozen eggs; Average weights yolk, albumen and shell; weight gain and final body weights of birds; and nitrogen balance. The digestible threonine: lysine ratio in the diet did not influence the analyzed variables except consumption of threonine which showed a linear effect. The ideal ratio of digestible threonine: lysine in diets for white laying hens at 42 to 58 weeks of age is 60%, which corresponds to the level of 0.461% of digestible threonine in the diet and daily intake of digestible threonine 446mg/bird.

RESUMO Este estudo foi realizado para determinar a relação ideal de treonina:lisina digestíveis para poedeiras leves no período de 42 a 58 semanas de idade. Foram utilizadas 240 poedeiras Hy Line W-36 com 42 semanas de idade durante 16 semanas. Os tratamentos foram distribuídos em delineamento inteiramente casualizado, com oito repetições e seis aves por unidade experimental. As dietas experimentais foram formuladas com cinco níveis de treonina digestível (0,461; 0,515; 0,569; 0,622 e 0,676%) proporcionando as cinco relações treonina:lisina digestíveis (60; 67; 74; 81 e 88%) estudadas. As variáveis analisadas foram: produção de ovos; consumo de ração, de lisina e de treonina; massa e peso médio dos ovos; eficiências de utilização da lisina por massa e ovos produzidos; conversões alimentares por massa e dúzia de ovos; pesos médios de: gema, albúmen e de casca; ganho de peso; peso corporal final das aves; e balanço de nitrogênio. As relações treonina:lisina digestíveis na dieta não influenciaram as variáveis analisadas, exceto o consumo de treonina que apresentou efeito linear. A relação ideal de treonina:lisina digestíveis na dieta para galinhas poedeiras leves de 42 a 58 semanas de idade é de 60%, que corresponde ao nível de 0,461% de treonina digestível na dieta e ao consumo diário de treonina digestível de 446mg/ave.

Relação treonina: lisina digestíveis na dieta de poedeiras leves de 42 a 58 semanas de idade

SUMMARY This study was conducted to determine the ideal ratio of digestible threonine: lysine in diets for laying hens at 42 to 58 weeks of age. Two hundred forty Hy Line W-36 laying hens were used at 42 weeks of age for 16 weeks. The treatments were distributed in a completely randomized design with eight replicates and six birds each. The experimental diets were formulated with five levels of digestible threonine (0.461; 0.515; 0.569; 0.622 and 0.676%) providing the five ratio of digestible threonine: lysine (60; 67; 74; 81 and 88%) studied. The variables analyzed were: egg production; feed intake; lysine intake; threonine intake; mass egg; average egg weight; lysine use efficiencies by mass and produced eggs; feed conversion per mass and dozen eggs; Average weights yolk, albumen and shell; weight gain and final body weights of birds; and nitrogen balance. The digestible threonine: lysine ratio in the diet did not influence the analyzed variables except consumption of threonine which showed a linear effect. The ideal ratio of digestible threonine: lysine in diets for white laying hens at 42 to 58 weeks of age is 60%, which corresponds to the level of 0.461% of digestible threonine in the diet and daily intake of digestible threonine 446mg/bird.

RESUMO Este estudo foi realizado para determinar a relação ideal de treonina:lisina digestíveis para poedeiras leves no período de 42 a 58 semanas de idade. Foram utilizadas 240 poedeiras Hy Line W-36 com 42 semanas de idade durante 16 semanas. Os tratamentos foram distribuídos em delineamento inteiramente casualizado, com oito repetições e seis aves por unidade experimental. As dietas experimentais foram formuladas com cinco níveis de treonina digestível (0,461; 0,515; 0,569; 0,622 e 0,676%) proporcionando as cinco relações treonina:lisina digestíveis (60; 67; 74; 81 e 88%) estudadas. As variáveis analisadas foram: produção de ovos; consumo de ração, de lisina e de treonina; massa e peso médio dos ovos; eficiências de utilização da lisina por massa e ovos produzidos; conversões alimentares por massa e dúzia de ovos; pesos médios de: gema, albúmen e de casca; ganho de peso; peso corporal final das aves; e balanço de nitrogênio. As relações treonina:lisina digestíveis na dieta não influenciaram as variáveis analisadas, exceto o consumo de treonina que apresentou efeito linear. A relação ideal de treonina:lisina digestíveis na dieta para galinhas poedeiras leves de 42 a 58 semanas de idade é de 60%, que corresponde ao nível de 0,461% de treonina digestível na dieta e ao consumo diário de treonina digestível de 446mg/ave.