Dietary phytase effects on copper requirements of broilers.

Information on the availability of Cu from plant feedstuffs for broilers in the presence of phytase is scarce. The present research has been conducted with the objective of evaluating the Cu requirements of broilers when fed corn-soy diets with or without phytase. A total of 640 one-day-old male Cobb x Cobb 500, allocated into 80 battery cages with 8 chicks in each, were fed a low Cu content diet (formulated with 8.58 ± 0.21 mg/kg Cu) without phytase from placement to day 7. Starting on day 8, battery cages were distributed into a 2 × 5 factorial arrangement (phytase-added diets X 5 with graded increases of supplemental Cu) until day 28. Feeding treatments (feeds added or not with phytase and 5 graded increases of Cu) were randomly distributed with 8 cages of 8 chicks. The basal non-supplemented feeds were formulated with corn and soybean meal (SBM) without any other significant Cu contributors. Supplemental Cu was from laboratory-grade Cu sulfate pentahydrate (CuSO5H20) which was increasingly added to the feeds. Phytase was added in excess to the producer recommendation (2,500 FYT) and had average analyzed values of 2,768 ± 135.2 FYT/kg whereas analyzed Cu values were: 8.05 ± 0.25, 11.25 ± 0.15, 14.20 ± 0.40, 16.55 ± 0.05, and 19.45 ± 0.45 mg/kg. Statistics were conducted using linear and quadratic polynomial regression models. No interactions occurred between dietary Cu and phytase (p > 0.05) for any response and no effects were found for the individual factors (phytase or dietary Cu) for Ht, Hb, varus, valgus, rotated tibia, and tibia breaking strength, as well as for Cu contents in breast, gastrocnemius tendon, and kidney (p > 0.05). However, the phytase-added diets led to higher BWG, lower FCR, and increased ileal digestible Cu (p < 0.05). The gradual increase in dietary Cu produced linear increases in Cu content in livers, as well as in excreta and retention (p < 0.05). Supplementing phytase at levels expected to maximize phytate degradation was demonstrated to improve BWG and FCR; however, no effects were observed when dietary Cu was increased to a maximum of 19.45 mg/kg. An increase of 8.8% in ileal digestible Cu was observed when birds were fed phytase.

Iron requirements of broiler chickens as affected by supplemental phytase.

Iron is routinely supplemented in broiler feeds intending to prevent dietary deficiencies. The present research was conducted with the objective of assessing Fe requirements of broilers when fed supplemental phytase. A total of 1,280 1-d-old male Cobb × Cobb 500 were distributed in a 2 × 5 factorial arrangement (phytase-supplemented feeds × 5 graded increases of supplemental Fe) in 80 battery cages, eight replications of eight chicks each. The trial was replicated once. Chicks were fed a Fe-deficient diet without phytase (Fe analyzed at 31.30 ± 3.79 mg/kg) from placement to 7 d and then randomly distributed into battery cages with corresponding dieting treatments with or without phytase and graded increases of supplemental Fe. Feeds were formulated with corn and soybean meal (SBM), laboratory-grade calcium carbonate, and phosphoric acid; therefore, the vast majority of dietary Fe originated from corn and SBM (analyzed diet had 53.3 ± 1.41 mg/kg Fe). Phytase was added in excess to the producer recommendation of 1,000 FYT (4,452 ± 487 FYT/kg analyzed) such that phytate degradation was expected to be maximized. Supplemental Fe was from laboratory-grade ferrous sulfate heptahydrate (FeSO47H2O) which was increasingly added to the feeds (analyzed Fe in the supplemented feeds were: 53.3 ± 1.41, 65.5 ± 0.59, 77.2 ± 1.97, 87.6 ± 1.72, 97.7 ± 1.33 mg/kg). There were no interactions between phytase and dietary Fe for any response throughout the study (P > 0.05). Supplementing phytase had no effects on Fe intake or Fe excretion, as well as on hematocrit (Ht), hemoglobin (Hb), ferritin, Fe contents in the liver or thigh muscle color (P > 0.05). However, phytase-supplemented feeds produced better live performance as well as higher ileal digestible energy and Fe digestibility (P < 0.05). No effects were found for dietary Fe in live performance at day 28 (P > 0.05). On the other hand, increasing dietary Fe led to linear increases in Fe retention and excretion, Fe contents in livers, as well as Ht and Hb at 14 d (P < 0.05). Quadratic responses (P < 0.05) were observed for Hb at 21 d, serum ferritin on days 14, 21, and 28 (maximum responses were 83.3, 104.0, 91.9, and 88.3 mg/kg Fe, respectively). In conclusion, supplementing Fe adding to a total of 97.7 mg/kg dietary Fe did not affect live performance traits. However, the average of Fe-related blood parameters was maximized at 91.9 mg/kg dietary Fe. Supplementing phytase provided a significant increase in Fe digestibility.

Iron is routinely supplemented in broiler feeds to prevent possible dietary deficiencies. We carried out an experiment with the objective of evaluating the Fe requirements of broilers fed with the exogenous enzyme phytase. From the eighth day, a total of 1,280 male broilers were distributed in a combination of diets supplemented with phytase or not and 5 graded increases in dietary Fe. Diets were formulated with corn and soybean meal, laboratory-grade calcium carbonate, and phosphoric acid. Phytase was added in excess (4,452 ± 487 FYT/kg analyzed) to facilitate complete degradation of dietary phytate. Laboratory-grade ferrous sulfate heptahydrate was increasingly added to the feeds to provide Fe. Iron in the experimental diets was present at 53.3 ± 1.41, 65.5 ± 0.59, 77.2 ± 1.97, 87.6 ± 1.72, 97.7 ± 1.33 mg/kg. Supplementing diets with phytase resulted in enhanced live performance, along with increased digestibility of ileal energy and Fe. Linear increases in Fe retention and excretion, hepatic Fe contents, and serum ferritin were observed with the progressive increase in dietary Fe. The supplementation of a total of 97.7 mg/kg of Fe in diets was found to have no significant impact on live performance traits. However, the Fe-related blood parameters reached their maximum levels at a dietary Fe level of 91.9 mg/kg. Phytase supplementation provided a significant increase in the digestibility of Fe and other nutrients evaluated.

Research Note: Corn energy and nutrient utilization by broilers as affected by geographic areas and carbohydrases.

Two experiments (Exp.) were conducted to evaluate the effects of exogenous carbohydrases on nutrient and energy utilization of corn with different compositions by broilers. In Exp. 1, a total of 448 Cobb 500 male chicks were distributed in a 2 × 4 factorial arrangement (corn from regions geographically located in the North or South of Brazil × 4 carbohydrases supplementation), with 8 replicate cages of 7 birds each. In Exp. 2, 672 Cobb 500 male chicks were fed 12 experimental feeds, in a 3 × 4 factorial arrangement [3 corn endosperm compositions (waxy, semi-dent, or semi-flint) × 4 carbohydrases], with 8 replicate cages of 7 birds. Birds were fed semi-purified test diets with 95.9% corn from d 14 to 24 in both studies. In Exp. 1, α-amylase, ß-xylanase, or carbohydrase complex (cellulase, glucanase, and xylanase) were added to the diet. In Exp. 2, α-amylase, ß-xylanase, or α-amylase + ß-xylanase were supplemented. Digestibility of DM, N, ether extract (EE), Ca, and P as well as AME, AMEn, and IDE were determined. In Exp. 2, jejunal starch digestibility was determined on d 24. Data were subjected to analysis of variance and means were compared by Tukey test (P ≤ 0.05). Corn from the North origin had higher AME, AMEn, and digestibility of DM and N compared to the South (P ≤ 0.05). Amylase supplementation led to increases of 3% in AME and 2% in N digestibility when compared to the non-supplemented feeds (P ≤ 0.01). In Exp. 2, the highest ME values and EE digestibility were observed in the semi-flint corn compared to the waxy, whereas the semi-dent presented the highest digestibility of N and starch. Corn diets supplemented with amylase + xylanase had improvements of 2.5% AMEn and 3% starch digestibility. In conclusion, energy and nutrient utilization of corn by broilers depend on the region where it was grown. Corn genetics, expressed by the endosperm composition, and carbohydrase supplementation influenced energy and nutrient utilization by broilers.

Intenção de compra e aceitação do consumidor da aparência visual de filetes de peito de frango acometidos com diferentes graus de wooden breast / Purchase intent and consumer acceptance of visual appearance of broiler breast fillets with varying degrees of wooden breast

O presente estudo analisou a intenção de compra e aceitação do consumidor de filés de peito de frango acometidos com diferentes graus da miopatia wooden breast (WB). Amostras de frango foram selecionadas, classificadas segundo o grau de amadeirado e embaladas. 55 julgadores realizaram teste de intenção de compra, avaliando, por análise sensorial, 4 embalagens com diferentes graus de miopatia WB e utilizando formulário de escala hedônica. Pôde ser observado que o gênero e a faixa etária dos consumidores não influenciam a frequência do consumo de carne de frango. Foi concluído que a faixa etária pode influenciar na intenção de compra de peitos de frango com WB. Os filés classificados nos graus 0 e 1 foram bem aceitos, enquanto os graus 2 e 3 de amadeirado sofreram redução na intenção de compra pelos consumidores.

Monitoramento de Salmonella spp. no sistema de criação de frangos de corte criados em pisos de plástico perfurados / Monitoring of Salmonella spp. in the system of chicken broilers created on perforated plastic floors

A Salmonellaé um problema dentro de granjas avícolas e abatedouros-frigoríficos. De caráter zoonótico, pode causar problemas ao homem. O estudo teve como objetivo avaliar o uso de pisos plásticos perfurados como substituto da cama de frango e a diminuição da carga microbiana. Os animais foram divididos em dois tratamentos: animais criados em cama (7 repetições) e animais criados no piso de plástico (7 repetições). Nos dias 4, 12, 25 e 40 de experimento, foram coletadas amostras de suabe de cloaca, suabe de arrasto do piso e amostras de cama para a contagem de coliformes totais, termotolerantes e Salmonella spp. Não foi possível encontrar diferença (p>0,0001) na contagem de coliformes entre os tratamentos. No teste presuntivo de Salmonella, até os 25 dias, os animais criados no piso tiveram as menores porcentagens de positivos. A utilização de pisos de plásticos e sua associação com protocolos higiênicos-sanitários pode ser uma estratégia para diminuir as contaminações bacterianas nos estabelecimentos avícolas comerciais e nas carcaças de frangos de corte.

Iron requirements of broiler breeder hens.

A study was conducted to investigate Fe requirements of broiler breeders. One-hundred-fifty-six Cobb 500 broiler breeder hens were individually placed in electrostatically painted cages at 22 weeks. The study was composed of an adaptation phase, in which hens were fed corn-soy-wheat bran diets until 35 wks. An Fe deficient mash diet (24.6 ppm Fe) was provided from 35 to 46 wk in order to induce a partial body Fe depletion. A production phase followed from 47 to 70 wk when hens were fed 6 diets with increasing Fe sulfate supplementation, which, upon analyses had 24.6, 48.6, 74.3, 99.6, 125.6, and 148.2 ppm Fe. Thirty hatching eggs from each treatment were randomly collected in the last wk of each production period and incubated. Hemoglobin and hematocrit were analyzed from 6 hens as well as all hatched chicks per treatment. Analyses of production and hatching data were conducted using quadratic polynomial (QP), broken-line (BL), and exponential asymptotic (EA) models. Effects of dietary Fe were observed for total eggs and total hatching eggs, egg yolk Fe content, and hen and chick hematocrit and hemoglobin (P < 0.05). These responses to added Fe were optimized when dietary Fe were 96.8, 97.1, 130.6, 122.6, 120.0, and 125.0 ppm (QP) and 76.4, 89.3, 135.0, 128.4, 133.8, and 95.0 ppm (BL) for total hatching eggs, egg yolk Fe content, and hen and chick hematocrit and hemoglobin, respectively. Optimization with the EA model was obtained for total hatching eggs, egg yolk Fe, and hen and chick hemoglobin at 97.9, 111.0, 77.9, and 96.3 ppm Fe for total hatching eggs, egg yolk Fe, and hen and chick hemoglobin, respectively. Adequate Fe levels are needed to maintain egg production as well as hatching chicks' indexes. Fe concentration in the yolk and diet are positively influenced. The average of all Fe requirement estimates obtained in the present study was 106 ppm total Fe, whereas averaged values for BL, QP, and EA models were 107, 113, and 97 ppm Fe, respectively.

Digestible lysine requirements of male broilers from 1 to 42 days of age reassessed.

Three experiments were conducted separately to estimate the digestible Lys (dig. Lys) requirements of Cobb × Cobb 500 male broilers using different statistical models. For each experiment, 1,200 chicks were housed in 48 floor pens in a completely randomized design with 6 treatments and 8 replicates. Broilers were fed diets with increasing dig. Lys levels from 1 to 12 d (Exp. 1), from 12 to 28 d (Exp. 2), and 28 to 42 d (Exp. 3). Increasing dig. Lys levels were equally spaced from 0.97 to 1.37% in Exp. 1, 0.77 to 1.17% in Exp. 2, and 0.68 to 1.07% in Exp. 3. The lowest dig. Lys diets were not supplemented with L-Lysine and all other essential AA met or exceeded recommendations. In Exp. 3, six birds per pen were randomly selected from each replication to evaluate carcass and breast yields. Digestible Lys requirements were estimated by quadratic polynomial (QP), linear broken-line (LBL), quadratic broken-line (QBL), and exponential asymptotic (EA) models. Overall, dig. Lys requirements varied among response variables and statistical models. Increasing dietary dig. Lys had a positive effect on BW, carcass and breast yields. Levels of dig. Lys that optimized performance using QP, LBL, QBL, and EA models were 1.207, 1.036, 1.113, and 1.204% for BWG and 1.190, 1.027, 1.100, and 1.172% for FCR in Exp. 1; 1.019, 0.853, 0.944; 1.025% for BWG and 1.050, 0.879, 1.032, and 1.167% for FCR in Exp. 2; and 0.960, 0.835, 0.933, and 1.077% for BWG, 0.981, 0.857, 0.963, and 1.146% for FCR in Exp. 3. The QP, LBL, QBL, and EA also estimated dig. Lys requirements as 0.941, 0.846, 0.925, and 1.070% for breast meat yield in Exp. 3. In conclusion, Lys requirements vary greatly according to the statistical analysis utilized; therefore, the origin of requirement estimation must be taken into account in order to allow adequate comparisons between references.

Técnicas de pulverização e imersão com distintos desinfetantes sobre ovos incubáveis / Immersion and pulverization techniques with different disinfectants above hatchin eggs

Foram conduzidos dois experimentos com o objetivo de avaliar a eficiência de diferentes princípios ativos desinfetantes e dois métodos de desinfecção de ovos. No primeiro experimento, as desinfecções foram realizadas por pulverização, enquanto que no segundo foram feitas por imersão, em granja de reprodutoras pesadas imediatamente após a postura. Os experimentos foram constituídos por um tratamento sem desinfecção e outros seis utilizando soluções desinfetantes: fenol sintético (1040ppm), digluconato de clorexidina (200ppm), amônia quaternária (800ppm), amônia quaternária (400ppm) + uréia (600ppm), amônia quaternária (130ppm) + glutaraldeído (370ppm) e formaldeído (7,7g m-3). Em cada experimento houve tratamentos-controle com fumigação (formaldeído) e sem desinfecção alguma. Após a desinfecção, 40 ovos por tratamento foram avaliados para presença de mesófilos totais, bolores e leveduras, coliformes totais, Pseudomonas sp e Aspergillus sp. Foi conduzido embriodiagnóstico nos ovos não eclodidos para determinação do período da mortalidade embrionária, da contaminação interior dos ovos, tendo sido determinado o nascimento de pintos impróprios para a criação e a eclodibilidade. No experimento em que os ovos foram desinfetados por pulverização, a associação entre amônia e glutaraldeído apresentou maior contaminação para mesófilos totais em relação aos demais tratamentos, à exceção do tratamento com fenol sintético, que apresentou contaminação semelhante a todos. Não foram detectadas diferenças entre os tratamentos para bolores e leveduras, coliformes totais, Pseudomonas sp e Aspergillus sp e, tampouco, entre os resultados de embriodiagnóstico. No experimento em que os ovos foram desinfetados por meio de imersão, foi verificada maior contaminação por mesófilos totais nos ovos não-desinfetados em relação aos desinfetados com os diferentes princípios ativos. Os ovos sem desinfecção também apresentaram maior contaminação por coliformes totais em...

Two experiments were conducted with the objective of evaluating different active compounds and methods of egg disinfection. In the first experiment, disinfection was done through spray whereas in the second it was done using immersion. Disinfections were performed at breeder house immediately after laying. In both experiments there were five treatments using the following disinfection solutions for each method: synthetic phenol (1040ppm), chlorexidine digluconate (200ppm), quaternary ammonium (800ppm), quaternary ammonium (400ppm) + urea (600ppm), quaternary ammonium (130ppm) + glutaraldehyde (370ppm). In both experiments there were a control treatment without disinfection and another using disinfection using fumigation with formaldehyde (7.7gm-3). After the disinfection procedures, forty eggs per treatment were evaluated for presence of total mesophiles, mould and yeast, total coliforms, Pseudomonas sp and Aspergillus sp. Embryo diagnosis was driven in no hatched eggs, for determination of embryo mortality period, interior contamination, and it was determined the birth of inappropriate chicks for rear and hatchability. In the experiment in that eggs were disinfected by pulverization, the association between ammonia and glutaraldehyde presented higher contamination for total mesophiles in relation to other treatments, with exception of synthetic phenol treatment, which presented similar contamination to all. Differences were not detected among treatments for mold and yeast, total coliforms, Pseudomonas sp and Aspergillus sp, and for embryo diagnosis results. In experiment in that eggs were disinfected through immersion, higher contamination was verified to total mesophiles in eggs no disinfected in relation to disinfected with the different active components. Eggs without disinfection also presented larger contamination for total coliforms in relation to ammonia and urea treatment, being similar to all other treatments. The analysis of...

Respostas de frangos de corte fêmeas de duas linhagens a dietas com diferentes perfis protéicos ideais / Responses of female broilers from two strain crosses to diets with differing ideal protein profiles

Foi conduzido um experimento com o objetivo de avaliar a formulação de dietas com diferentes perfis protéicos ideais para frangos de corte fêmeas. Foram usadas aves dos cruzamentos Cobb x Cobb 500 e Ross x Ross 308. As dietas foram fornecidas em um programa alimentar de quatro fases: 1 a 7, 7 a 21, 21 a 31 e 31 a 37 dias de idade. Até os 21 dias de idade, as aves receberam dietas com perfis protéicos ideais altos (A), médios (M) e baixos (B). De 21 dias até o final do experimento, houve uma redistribuição dos tratamentos em que metade das aves recebendo dieta A passaram a receber dieta B e metade daquelas recebendo dieta B passaram a receber dieta A. As aves recebendo dieta M permaneceram com o mesmo perfil protéico por todo o período experimental. Foi utilizado um delineamento inteiramente casualizado em arranjo fatorial com três perfis protéicos e duas linhagens até os 21 dias de idade e cinco perfis protéicos ideais e duas linhagens dos 21 aos 37 dias de idade. As aves da linhagem Cobb apresentaram maior peso vivo aos 21 dias de idade e melhor conversão alimentar até o final do experimento, enquanto aves Ross apresentaram maior consumo de ração durante todo o período experimental. Ainda para frangos Ross, a proporção de carne de peito aos 31 dias de idade foi maior e a proporção de coxas + sobrecoxas, aos 31 e 37 dias de idade, menores em relação às aves Cobb. As aves recebendo as dietas A e M até os 21 dias de idade apresentaram respostas zootécnicas similares, ambas superiores às aves recebendo dieta B. A avaliação dos dados aos 31 e 37 dias de idade demonstrou que as aves do programa alimentar BB apresentaram peso vivo semelhante, maior consumo de ração e conversão alimentar pior na comparação com as aves dos demais tratamentos. Já na avaliação após o abate, as únicas diferenças observadas foram relativas à proporção de gordura abdominal aos 31 dias de idade. Foi possível concluir que aves Cobb apresentaram melhor conversão alimentar...

This study was conducted with the objective of evaluating the performance of two broiler strain crosses fed diets having 3 different ideal protein profiles. One day old Cobb x Cobb 500 and Ross x Ross 308 broiler chicks were in a feeding program of 4 phases from 1 to 7, 7 to 21, 21 to 31 and 31 to 37 days of age and having high (H), medium (M) and low (L) ideal protein profiles. At 21 days of age, half of the replications fed H and L protein diets changed to L and H, respectively, whereas those receiving M remained all the way to the end in the same protein level. The experimental design was completely randomized in a factorial arrangement having 3 ideal protein levels and 2 strain crosses until 21 days of age and 5 ideal protein levels and 2 strains from 21 to 37 days old was used. Cobb broilers had higher body weight at 21 days of age and better feed conversion until the end of the experiment, whereas Ross broilers showed higher feed intake during all the experimental period. At processing, Ross broilers had higher breast meat yield at 31 days old, but Cobb broilers had higher yield of leg quarters both at 31 and 37 days. At 21 days, H and M diets presented similar live performance; however, both were superior when compared to L diets. Differences in body weigh at 31 and 37 days due to feeding programs were not apparent; however birds fed L diets in both periods had poorer feed conversion and higher feed intake than all the other treatments. The only processing difference due to feeding program was an increased proportion of abdominal fat when birds were fed L diets in one of the two periods. It was possible to conclude that Cobb broilers had better feed conversion independently of the feeding program used and that the M ideal protein levels were adequate to support maximum live performance and carcass yields.

As influências do positivismo e do higienismo nos primórdios da Educação Física Brasileira e na Ginástica NacionalBrasileira (capoeira) / Las influencias del positivismo y del higienismo en las primeras etapas de la Educación Física Brasileña y en la Gimnástica Nacional Brasileña (capoeira) / The influences of positivism and hygienism in the first stages of Brazilian Physical Education and in Brazilian National Gymnastics (capoeira)

Este trabalho analisa as influências dos pensamentos filosóficos do positivismo e do higienismo nos primórdios da Educação Física e da Capoeira no Brasil. Trata-se do resultado de uma pesquisa histórica baseada em fontes primárias. Os parâmetros metodológicos tiveram como referencial analítico os estudos de documentos encontrados em arquivos públicos, bem como de levantamentos bibliográficos e estudos correlacionais. Tem como objetivo aprofundar conhecimentos a respeito de fatos que transcorreram em nossa história recente com repercussão no atual modo de vida, fatos que passam despercebidos. Ao final apresenta os eixos organizacionais da Ginástica Nacional (Capoeira) e seu contexto. PALAVRAS-CHAVE: Educação Física/história/Brasil. Capoeira. Filosofia.

This work analyzes the influences of the philosophical doctrines of positivism and hygienism in the first stages of Physical Education and Capoeira in Brazil. The work is the result of a historical research based on primary sources. The methodological parameters had as an analytical referential documental studies found in public archives, as well as bibliographical surveys and correlation studies. It has as a goal to deepen knowledge regarding facts that happened in our recent history, and had bequeathed us our current way of life, facts that normally go unnoticed. To this end it presents the organizational axles of Brazilian National Gymnastics (Capoeira) and its context. KEYWORDS: Physical Education/history/Brazil. Capoeira. Philosophie.

Este trabajo analiza las influencias de las doctrinas filosóficas del positivismo y del higienismo en las primeras etapas de la educación física y de la Capoeira en el Brasil. El trabajo es el resultado de una investigación histórica basada en fuentes primarias. Los parámetros metodológicos han tenido como referencial analítico estudios documentales encontrados en archivos públicos, así bien estudios bibliográficos e de correlación. Tiene como meta profundizar el conocimiento respecto a hechos que sucedieron en nuestra historia reciente, y nos han legado nuestra manera de vida actual, hechos que van normalmente inadvertidos. Con este fin presenta los ejes de organización de la gimnástica nacional brasileña (Capoeira) y de su contexto.PALABRAS LLAVE: Educación Física/historia/Brasil. Capoeira. Filosofia.

Respostas de frangos de corte a aumentos graduais na relação entre treonina e lisina / Broiler responses to graded increases in the threonine to lysine ratio

Um experimento foi conduzido com o objetivo de avaliar o efeito de relações crescentes entre treonina (Thr) e lisina (Lys) digestível em dietas de frangos de corte nas repostas produtivas dos 15 aos 37 dias de idade. Os aumentos dos níveis de treonina das dietas foram obtidos a partir de inclusões crescentes de farelo de soja (FS) ou L-treonina (L-Thr). Foram alojados 1.200 frangos de corte machos Ross x Ross 308 em arranjo fatorial com três relações entre Thr e Lys (63,5, 66,0 e 68,5 por cento) e as duas fontes de Thr supracitadas. Cada um dos seis tratamentos foi constituído por oito repetições de 25 aves. As dietas foram formuladas para garantir o nível mínimo de exigência para os demais nutrientes e energia. Não houve efeito do nível de treonina sobre respostas de desempenho zootécnico, consumo de água, matéria seca da cama, lesões de pododermatite e rendimento de carcaça e cortes. Também não foi observado efeito da fonte de Thr sobre peso corporal, consumo de dieta, matéria seca da cama, lesões de pododermatite, rendimentos de carcaça, filé de peito, coxas e sobrecoxas. Entretanto, a conversão alimentar foi melhor (P=0,009) e o consumo de água maior (P=0,011) quando o aumento em Thr foi originado do FS, enquanto o rendimento de peito foi superior (P=0,035) para as dietas suplementadas com L-Thr. Foi possível identificar uma resposta diferenciada entre fonte e nível de Thr para ganho de peso e CA, demonstrando que, quando a relação entre Thr e Lys foi de 68,5 por cento, existiu uma evidente melhora para as aves recebendo este nível de Thr a partir do FS. As quantidades de aminoácidos (AA) essenciais a partir do quarto AA limitante foram superiores para as dietas com níveis crescentes de FS. Supõe-se que as diferenças obtidas entre as respostas das aves recebendo dietas com o aumento em Thr a partir de L-Thr ou FS tenham sido devidas a desiguais quantidades ou balanceamento de AA essenciais consumidos a partir do quarto AA limitante. A relação...

An experiment was carried out with the objective of evaluating the effects of graded increases in the ratios between digestible threonine (Thr) and lysine (Lys) in the diet on broilers from 15 to 37 days old. The increases on Thr levels were obtained with higher amounts of soybean meal (SBM) or L-threonine (L-Thr) in the diets. One thousand and two hundred Ross x Ross 308 male chicks were placed in a factorial arrangement with the three ratios between Thr and Lys (63.5, 66.0 and 68.5 percent) and the two sources of Thr previously cited. Each of the six treatments had eight replicates of twenty five birds. The diets were formulated to attain minimum requirement levels of other nutrients and energy. There were no effects of the Thr level on live performance responses, water intake, litter dry matter, foot pad dermatitis, carcass and processing yields. In addition, there were no effects of the source of Thr on body weight, feed intake, litter dry matter, foot pad dermatitis, carcass, breast tenders, thighs and drumsticks yields. However, feed conversion was better (P=0.009) and water intake was higher (P=0.011) when the increase on Thr was originated by SBM, whereas breast meat yield was higher (P=0.035) with diets supplemented with L-Thr. An interaction between level and source of Thr was identified for weight gain and feed conversion demonstrating improvement when birds were fed 68.5 percent Thr to Lys ratio originated from SBM. Amounts of essential amino acid (AA) quantities after the third limiting AA were greater in the diets with increased SBM. Supposely, differences obtained in broiler responses when fed diets with Thr increased from SBM or L-Thr were related to different amounts or balances in the intake of essential AA. A Thr to Lys ratio of 63.5 percent was considered sufficient to maximize broiler performance, whereas increases in Thr obtained exclusively from SBM influence the results probably because of higher amounts of AA...