No abstract

This study was conducted to determine the standardized ileal digestible lysine (SID Lys) requirements for white commercial layers in peak egg production phase. A total of two hundred eighty-eight 24 week-old Hy-Line W-36 layers were randomly assigned to one of six treatments groups, with eight replicates of six hens each. A basal diet, SID Lys-deficient, was graded supplemented with L-Lysine HCl (78.4%) in order to produce experimental treatments (6.0, 6.6, 7.2, 7.8, 8.4 and 9.0 g SID Lys/kg diet). Throughout the 16-week-feeding trial (24 to 40 weeks of age) hens had free access to water and mash feed. Data were analyzed as one-way ANOVA and optimum SID Lys level for each dependent variable assessed were estimated using polynomial and linear broken-line regression model. Feed intake and SID Lys intake were both linearly enhanced by graded SID Lys levels. According to linear broken-line regression model, the breakpoint for egg production, egg weight, and egg mass occurred at 8.14, 8.56 and 8.35 g SID Lys/kg diet, respectively. The breakpoint for feed conversion per egg mass (kg/kg) and per dozen of eggs (kg/dozen) occurred at 8.48 and 7.80 g SID Lys/kg diet, respectively. Eggshell weight and albumen weight were unaffected by dietary SID Lys supply. Weight gain and yolk weight reached optimum values at 8.33 and 8.03 g SID Lys/kg diet, respectively, according to linear broken-line regression model. In conclusion, SID Lys requirement for white commercial layers in peak egg production phase is 8.48 g/kg diet, which corresponds to an average daily SID Lys intake of 813 mg/hen.

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.

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.

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-3β, 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.

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Objective: A trial was conducted to investigate the effects of supplemental levels of Mn provided by organic and inorganic trace mineral supplements on growth, tissue mineralization, mineral balance, and antioxidant status of growing broiler chicks.Methods: In total, 500 8-d-old male chicks were used in 10-day feeding trial, with 10 treatments and 10 replicates of 5 chicks per treatment. A 2 x 5 factorial design was used where supplemental Mn levels (0, 25, 50, 75, and 100 mg Mn/kg diet) were provided as MnSO 4 .H 2 O or MnPro. When Mn was supplied as MnPro, supplements of zinc, copper, iron, and selenium were supplied as organic minerals, whereas in MnSO 4 .H 2 O supplemented diets, inorganic salts were used as sources of other trace minerals. Performance data were fitted to a linear-broken line regression model to estimate the optimal supplemental Mn levels.Results: Manganese supplementation improved body weight (BW), average daily gain (ADG) and feed conversion ratio (FCR) compared with chicks fed diets not supplemented with Mn.Manganese in liver, breast muscle, and tibia were greatest at 50, 75, and 100 mg supplemental Mn/kg diet, respectively. Higher activities of glutathione peroxidase (GSH-Px) and superoxide dismutase (total-SOD) were found in both liver and breast muscle of chicks fed diets supplemented with inorganic minerals. In chicks fed MnSO 4 .

This trial was performed to determine the dietary digestible threonine-to-lysine (dig. Thr-to-Lys) ideal ratio for laying hens fed with low-protein diets from 24 to 40 weeks of age. At 24 weeks of age, two hundred forty Hy Line W-36 laying hens were randomly assigned to five treatments, represented by five dig 67; 74; 81 and 88%) 0.610; 0.580; 0.614; 0.599; 0.599 and 0.643%, 75; 80; 78; 78