Two independent experiments were conducted with male Cobb × Cobb 500 broilers to determine the optimal valine-to-digestible-lysine ratio for broiler development. We conducted a randomized block experiment with 7 treatments, each with 8 replicates of 25 starter birds (8 to 21 d of age) and 20 finisher (30 to 43 d of age) birds. To prevent any excess of digestible lysine, 93% of the recommended level of digestible lysine was used to evaluate the valine-to-lysine ratio. The utilized levels of dietary digestible lysine were 10.7 and 9.40 g/kg for the starting and growing phases, respectively. A control diet with 100% of the recommended level of lysine and an adequate valine-to-lysine ratio was also used. The feed intake, weight gain, feed conversion ratio, and carcass parameters were evaluated. The treatments had no significant effect on the feed intakes or carcass parameters in the starter and finisher phases. However, during both of the studied phases, we observed a quadratic effect on weight gain and the feed conversion ratio. The broilers of both phases that were fed test diets with the lower valine-to-lysine (Val/Lys) ratio had poorer performance compared with those broilers fed control diets. However, when higher Val/Lys ratios were used for the starting and growing broilers that were fed test diets, the 2 groups had similar performance. During the starting phase, in broilers that were fed a higher Val/Lys ratio, weight gain, and the feed conversion ratio improved by 5.5% compared with broilers fed the basal diets. The broilers in the growing phase also had improved performance (by 7 to 8%) when the test diets had higher Val/Lys ratios. Based on the analysis of the starter phase data, we concluded that the optimal digestible Val/Lys ratio for Cobb × Cobb 500 broilers is 77%, whereas for birds in the finisher phase (30 to 43 d of age), a digestible Val/Lys ratio of 76% is suggested.

Two experiments were carried out to evaluate the effects of the dietary inclusion of different dietary sunflower meal (SFM) levels (0% and 20%), with or without the supplementation of an enzyme complex (EC) (cellulase, β-glucanase, xylanase, and phytase) on broiler performance, carcass and cuts yields, economics, and dietary AMEn values. A randomized block experimental design, with a 2x2 factorial arrangement of eight replicates of 20 birds each, was used to test performance. A completely randomized experimental design with a 2x2 factorial arrangement of eight replicates of four birds each was used to test metabolism. No interaction effects between SFM and EC were observed on performance. Although SFM significantly reduced feed intake in the starter phase and total period, weight gain was not different in these phases. Feed: gain ratio improved with the use of SFM in all phases, probably due to the dietary inclusion of oil, which may have improved digestibility. There was a significant increase in weight gain with the use of EC in the starter phase, which is possibly explained by the immature digestive system of birds at this age. There were no SFM or EC significant effects on carcass or cuts yields. There was no significant effect of the addition of EC on dietary AMEn values; however, EC significantly improved the apparent metabolizability coefficients of phosphorus and calcium

Modern broilers have been submitted to continuous genetic improvement, and therefore, their nutritional requirements must be constantly updated to ensure their performance. Two experiments were carried out to evaluate different digestible lysine levels for starter (10-21 days) and grower (22-35 days) phases. The experiments were carried out with male and female Cobb 500 broilers, distributed according to a randomized block experimental design in a 5x2 factorial arrangement (5 increasing digestible lysine levels x 2 sexes), totaling 10 treatments, with 8 replicates of 22 and 20 birds during the starter and grower phase, respectively. Digestible lysine levels of 1.06, 1.12, 1.18, 1.24, and 1.30 were used in the starter diets (10-21 days) and 0.9, 0.98, 1.04, 1.10, and 1.16% in the grower diets (22-35 days). Based on the statistical analyses of the evaluated performance parameters, digestible lysine requirements for maximum performance were determined as 1.22% for males and 1.24% for females in the starter phase, and 1.16% for both sexes in the grower phase. Carcass and performance results indicate that digestible lysine requirements vary with sex and evaluated production parameter. Considering the most relevant broiler production parameters, in 22-to 35-d-old males, digestible lysine requirement for breast meat yield (1.16%) was higher than those for feed conversion ratio (1.07%) and weight gain (1.05%).

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-The objective of this study was to evaluate the effect of feeding herbal extracts for broilers on performance and histology of the intestinal mucosa and its effects on the profiting from the metabolizable energy of experimental diets.For so, two experiments were conducted. In experiment I, the inclusion of different herbal extracts in diets on performance and intestinal histology of broilers was evaluated, and in experiment II, the values of apparent metabolizable energy and metabolizable energy corrected by the nitrogen balance of the experimental diets were studied. Treatments consisted of: positive control diet; positive control + avilamycin; negative control; negative control + 100 ppm of a complex containing three different herbal medicines (pepper, cinnamon and oregano); negative control + 75 ppm garlic extract; negative control + 150 ppm garlic extract. In the performance experiment, which comprised the period of 1 to 40 days of age, 960 male broilers were distributed in a randomized block design, with six treatments and eight replicates, with 20 birds per experimental unit.In experiment II, the method adopted was the traditional of total excreta collection with male broiler chicks in the age of 14 to 24 days, in a completely randomized design, with six treatments and eight replicates with five birds per experimental unit. The intestinal villus height was improved with addition of the composite containing the three herbal extracts; however, crypt depth and villus/crypt ratio were not affected. The use of herbal extract in diets for broilers promotes performance similar to that with the use of antibiotics. Herbal extracts can be incorporated into diets replacing antibiotics without compromising the metabolizable energy of diets, performance or intestinal mucosa for broilers in the period of 1 to 40 days of age.

Mycotoxins are secondary metabolites produced by several fungal species, toxic to humans, animals and plants. Their ingestion, inhalation or dermal absorption may cause different diseases and even death. These compounds have been described for many decades, however in the beginning of the s, they have been chemically characterized due to the discovery of aflatoxins [ ]. The word aflatoxin is the combination of other words a for Aspergillus genus, fla for the species flavus and toxin, meaning poison [ ]."flatoxin is the mycotoxin generating the greatest losses and the highest management costs due to its extremely high toxicity on a unit basis, and its long history of stringent regulation. The costs are inversely related to the regulatory level that must be met, and lower concentration allowances will increase the costs of crop management. Several effective ways for the management of mycotoxin contamination in agriculture have been stressed. One strategy to manage mycotoxin contamination and decrease health risks and economic costs is to instruct food producers and handlers on how to minimize mycotoxin contamination, and to encourage the adoption of process-based guidelines such as Good "gricultural Practices G"Ps before harvest and good manufacturing practices GMPs after harvest. These actions would minimize risk throughout the production, handling, and processing chain, and can complement product standards [ ]. To control the presence of aflatoxins in foods, many countries established maximum tolerated concentrations through legislation Van Egmond, a cited [ ] .This chapter focuses on properties of aflatoxins and their occurrence in feeds and animal products as meat, eggs, liver, kidneys and milk. Topics regarding mycotoxins absorbents and legislation in feed ingredients and feeds are also covered.

Em vista da constante evolução do melhoramento genético de frangos de corte, torna-se necessária a determinação das exigências nutricionais dessas aves, para assegurar seu desempenho. Assim sendo, dois experimentos foram realizados, com o objetivo de avaliar diferentes relações de metionina + cistina / lisina digestível sobre o desempenho de frangos de corte, nas fases de 11 a 21 e 22 a 35 dias de idade. O delineamento experimental nas duas fases avaliadas foi o de blocos casualizados, em arranjo fatorial 2x5+2, (2 sexos e 5 diferentes relações met+cis/lis digestível e um tratamento controle para cada sexo), com oito repetições de 23 e 20 aves (COBB 500) por unidade experimental, nas fases descritas. As dietas atenderam às exigências, exceto para metionina + cistina e lisina. Para evitar o excesso de lisina digestível, seu nível foi calculado para 97% do recomendado para todas as fases. O tratamento controle foi adequado em lisina e metionina + cistina. As relações metionina + cistina/lisina digestível, para máximo desempenho de frangos de corte, machos e fêmeas, respectivamente, são de 75,53 e 78,23%, na fase de 11 a 21 dias, e 78,83 e 79,82%, na fase de 22 a 35 dias.

Three experiments were carried out to estimate the optimal ratios of digestible phenylalanine + tyrosine (Phe + Tyr), histidine (His), and leucine (Leu) relative to digestible lysine (Lys) for performance and carcass criteria of Cobb-500 broilers from 8 to 17 d of age. In each experiment, 160 male chicks were allocated to a completely randomized experimental design with eight replicate pens, each receiving five dietary treatments. A common, semi-purified basal diet was formulated to meet all dietary recommendations except for those of the tested amino acids (i.e., Phe + Tyr, His, and Leu). Growth performance and carcass characteristics data were analyzed using various requirement-estimation models, including 95% of the quadratic regression, linear response plateau (LRP; i.e., stepwise regression), LRP-to-quadratic regression ratio; and quadratic broken line (QBL). Graded digestible Phe + Tyr ratios elicited a quadratic response (P < 0.05) in body weight gain and linear responses (P < 0.05) in breast and breast fillet weights. Linear effects (P < 0.05) were also observed when graded ratios of digestible His were fed for feed intake and weight gain, and quadratic responses (P < 0.05) were noted for feed conversion ratio and breast and breast fillet weights and yields. Graded Leu ratios elicited quadratic responses (P < 0.05) in feed intake, weight gain, and breast and breast fillet weight and yield. Based on growth and carcass parameters, the estimated ideal digestible ratios of Phe + Tyr, His, and Leu relative to digestible Lys were 112, 38, and 104%, respectively, for broiler chicks raised from 8 to 17 d of age.