The objective of this study was to evaluate the effects of golden mussel flour (GMSF) contaminated with increasing rates of cadmium (Cd) as a replacement for limestone as a Ca source, in broiler chicken feed from 14 to 42 days of age. A total of 60 animals were assigned to four treatments (inclusion rates of Cd: 6.94, 14.55, 22.40, and 30.00 mg Cd kg-1) with five replications in a completely randomized design. At 42 d, blood samples were collected to evaluate serum concentrations of aspartate amino transferase (AST), alanine amino transferase (ALT), gamma glutamyl transferase (GGT), total bilirubin, Ca, P, and Cd. After slaughter, tissues were collected to evaluate Cd concentration in bone parameters. Growth performance of broiler chickens and Cd content in the breast meat were not affected by the inclusion rates of Cd in the GMSF. However, there was an effect of Cd in GMSF on the concentration of Cd in the skin, liver, bones, feathers, and serum; ALT; and total bilirubin. Bone flexibility had a quadratic response to increasing inclusion rates of GMSF; serum Ca concentration increased linearly and there was no effect on serum P concentration. Concentrations of Cd in GMSF above 20 mg kg-1 caused high Cd contamination in broiler tissues. Therefore, it was concluded that Cd concentrations above 6.94 mg kg-i in broiler diets caused high Cd concentrations in meat and organs that are above those permitted for human consumption.

The dietary inclusion of hydroethanolic extract of guavira seed or peel was evaluated on broiler performance, intestinal morphometry, carcass yield, and meat quality. A total of 1,680 male chicks, one day old, were distributed in a 2x5+2 factorial design (hydroethanolic extract of guavira seed (HEGS) or hydroethanolic extract of guavira peel (HEGP); 100; 200; 300; 400 and 500 mg/kg of inclusion and a positive control (PC) with antibiotics and negative control (NC) without growth promoter), with seven replicates and 20 birds each. A better feed conversion ratio (FCR) was observed from days 1-7 and days 1-21 on the PC diet than on the NC diet. FCR from 1-7d of broilers on PC was better than those on HEGS or HEGP, and this better FCR was maintained until 21 d for the HEGS treatment. The HEGP diet showed lower average feed intake and better FCR for the total period compared to NC diets. Higher carcass yield and a higher L15 value for breast meat was observed in the HEGP group compared to HEGS. Broilers fed the PC diet showed a higher a* value 15 min and 24 h postmortem, higher water retention capacity in breast meat compared to birds fed HEGS, and a higher value of a* 24 h postmortem than those receiving NC. The inclusion of 100 to 500 mg/kg of HEGP or HEGS did not improve performance, intestinal morphometry, and carcass characteristics when compared to the performance-enhancing antibiotic. However, the HEGP diet provided better performance of broilers than the non-use of growth promoter additives in the diet.

The objective of this study was to evaluate the use of clinoptilolite zeolite to enhance performance in broiler chickens. Nine hundred male broiler chickens were distributed in a completely randomized design to four treatments with nine repetitions. Treatments included clinoptilolite zeolite in the diet at 0, 2500, 5000 and 10000 grams/ton. Inclusion of zeolite caused a linear increase in ammonia released by the litter after 21 days, with greater effects at 42 days. The digestibility coefficient for dry matter increased, whereas the digestibility coefficients for crude protein, gross energy, and ash were not affected. Zeolite affected the digestibility of dry matter, gross energy and ash, with digestible gross energy and digestible ash showing a quadratic effect. The same effect was shown in the percentage of abdominal fat and the relative weight of the pancreas. Zeolite did not change the performance, serum levels and quality of the litter at 42 days old. It improved the percentage of digestible nutrients and increased pancreas weight.

Homeopathic products (HP) are a preventive and therapeutic alternative in pig farming. This study evaluated the effect of the concentration of dietary HP on performance, carcass traits, meat quality, and plasma metabolites of growing-finishing pigs. A total of 60 crossbred male pigs (Agroceres PIC * DanBred), immunocastrated at 90 and 120 days old, with an initial BW of 30.71 ± 2.60 kg were allocated in a completely randomized design to three treatments: i) control diet (CT), without HP), ii) CT + HPi (Figotonus® and Sanoplus®) (1 g/kg of diet), and iii) CT + HP2 (Figotonus and Sanoplus) (2 g/kg of diet). The results indicate that pigs fed diets containing HP2 had a greater average daily gain compared with those fed the control diet, although a higher feed efficiency was observed when pigs were fed the HP1 diet. Animals fed the HP2 diet showed a slight increase in initial postmortem pH in the Longissimus dorsi muscle compared to the control group. Pigs fed HP2 showed a higher initial temperature in the L. dorsi than those fed the control diet. However, there was no effect on plasma metabolite concentration. Based on the results of the present study, the HP1 diet enhanced the performance of finishing pigs without negative effects on meat traits and plasma metabolites.

The objective was to evaluate the effect of diets containing various levels of phytate and phytase on broilers from 1 to 42 days old. The treatments consisted of a combination of diets containing high (HP), medium (MP) and low (LP) phytate with positive control diet (PC) and a negative control diet (NC) that was similar to the PC in energy and protein but with less calcium and phosphorus. Three additional diets, based on the NC were supplemented with 500, 1000, or 1500 FTU kg-1 of phytase. Broilers that received the NC diet exhibited the lowest weight gain (WG), whereas those supplemented with 1000 FTU kg-1 obtained 2.84% higher WG compared with PC. Broilers that received NC had the lowest breaking strength and dry matter. Birds fed HP diets that received NC and NC + 500 FTU kg-1 had a higher concentration of serum Ca and P than birds fed LP diets. Broilers fed the NC and NC + 500 and 1000 FTU kg-1 had lower tibia Ca levels compared with birds fed the PC. Broilers fed HP diets had higher tibia Ca content than MP. Phytase supplementation had a positive response in diets with reduced Ca and P. Based on regression analysis the optimum inclusion of phytase to improve broiler performance parameters was calculated as 952 FTU kg-1.

This article assessed the performance, carcass yield, and meat quality of finishing broilers fed increasing levels of hydroethanolic extract of guavira fruit peel (HEGP) were assessed. A total of 480, three-weeks-old male broilers were randomly allocated to dietary levels of HEGP (0, 100, 200, 300, 400, and 500 mg/kg), with five replicates and 16 birds each. There was a quadratic effect of HEGP inclusion on weight gain (Wg) and feed conversion ratio (FCR), with the greatest WG and FCR being calculated at levels of 314 and 219 mg/kg HEGP, respectively. Broilers fed diets containing the extract had better performance than those fed an extract-free diet. There was no effect of extract inclusion on carcass yield and cuts. There was a quadratic effect of HEGP inclusion on a* (redness) of thigh meat at 15 min post-mortem, and on waterholding capacity (WHC), with the lowest and highest values being calculated at 270 mg/kg and 263 mg/kg HEGP, respectively. There was a quadratic influence of HEGP inclusion on the malonaldehyde content at 30-day storage, with highest value being calculated at 218 mg/kg HEGP. Dietary inclusion of 219 mg/kg of HEGP resulted in better FCR for broilers in the finishing phase but without improvement in meat quality.

RESUMO Os valores energéticos da glicerina bruta (GB) foram determinados para frangos de corte em diferentes idades, por meio da utilização do método proposto por Matterson e de regressões polinomiais. Foram realizados dois ensaios: de 11 a 21 dias e de 31 a 41 dias de idade das aves; em ambos, as aves foram distribuídas em um delineamento experimental inteiramente ao acaso, com uma ração referência (RR), sem GB, e três rações testes com substituição de 5%, 10% e 15% da RR por GB. Foram calculados os valores de energia metabolizável pelo método de Matterson, sendo os valores de energia metabolizável aparente (EMA) utilizados na análise de regressão polinomial. Os valores médios da EMA corrigida pelo balanço de nitrogênio (EMAn), o coeficiente de metabolizabilidade da EB (CMAEB) e o corrigido para o balanço de nitrogênio (CMAEBn) da GB, na matéria natural, para a fase de 11 a 21 dias, pelo método de Matterson, foram de 10,08 MJ kg-1, 10,04 MJ kg-1, 67,06% e 66,74%, respectivamente. A inclusão de GB apresentou um efeito linear crescente para os CMAEB e os CMAEBn. Na fase de 31 a 41 dias, foram de 10,38 MJ kg-1, 10,27 MJ kg-1, 69,02% e 62,24%, respectivamente. Por meio das equações de regressões polinomiais, o valor de EMAn estimada foi de 10,49 MJ kg-1 e 10,18 MJ kg-1, respectivamente. Os valores de EMAn da GB para as idades 11 a 21 e 31 a 41 dias foram de 10,04 MJ kg-1 e 10,26 MJ kg-1, respectivamente. De acordo com as equações propostas por Matterson e com o método de Adeola, os valores de EMAn foram 10,49 e 10,20 MJ kg-1 para cada fase.

ABSTRACT The energetic values of crude glycerin (CG) were determined for broilers at different ages using the method proposed by Matterson and by polynomial regressions. Two trials were performed with broilers from 11 to 21 and from 31 to 41 days of age. The birds were distributed in a completely randomized experimental design with a reference ration (RR), without CG, and three ration tests with replacement of 5%, 10%, and 15% of RR by CG. The metabolizable energy values were calculated by the Matterson method, and the apparent metabolizable energy (AME) values were used in polynomial regression analysis. The mean values of AME, apparent corrected for nitrogen balance (AMEn), metabolizable coefficient of gross energy (CAMEB), and corrected for nitrogen balance (CAMEBn) of CG, for the phase from 11 to 21 days by the Matterson method were 10.08 MJ kg-1, 10.04 MJ kg-1, 67.06%, and 66.74%, respectively. The inclusion of CG presented an increasing linear effect for CAMEB and CAMEBn in this period. From 31 to 41 days, these values were 10.38 MJ kg-1, 10.27 MJ kg-1, 69.02%, and 62.24%, respectively. The predicted AMEn value through the polynomial regression equations was 10.49 MJ kg-1 and 10.18 MJ kg-1, respectively. According to the equations proposed by Matterson, the crude glycerin EMAn values for broilers from 11 to 21 and 31 to 41 days of age were 10.04 MJ kg-1 and 10.26 MJ kg-1, respectively. According to Adeola's method the AMEn values were 10.49 and 10.20 MJ kg-1 for each phase.

RESUMO Foram determinados os valores energéticos e a composição bromatológica do resíduo seco de fecularia (RSF) para frangos de corte, na fase de crescimento, utilizando ou não enzimas carboidrases. Os tratamentos foram distribuídos em esquema fatorial 2x4 + ração referência, sendo uma RR sem adição de RSF e quatro tratamentos experimentais com 10%, 20%, 30% e 40% de inclusão do RSF e a suplementação ou não com carboidrases. A composição química encontrada para o RSF, na MN, foi de 89,86% de matéria seca, 0,98% de proteína bruta, 3519kcal kg-1 de energia bruta, 0,19% de extrato etéreo, 27% de fibra em detergente neutro, 19,5% de fibra em detergente ácido, 0,33% de cálcio, 0,43% de fósforo, 0,46% de potássio e 0,12% de magnésio. O uso de carboidrases proporcionou um aumento de 173 e 213kcal kg-1 nos valores de EMA e EMAn, respectivamente, resultando em 1828kcal kg-1 EMA e 1840kcal kg-1 EMAn. Concluiu-se que os maiores níveis de EMA e EMAn foram encontrados para o nível de inclusão médio do RSF de 35% e que a suplementação enzimática pode promover aumento desses parâmetros em até 12% em dietas para frangos de corte na fase de crescimento.

ABSTRACT The energetic values and the bromatological composition of the dry residue of cassava (DRC) were determined for growing broilers with or without carbohydrase enzymes. The treatments were distributed in a 2x4 + reference diet factorial scheme, with one RD without addition of DRC and four experimental treatments with 10, 20, 30 and 40% inclusion levels of RSF and supplementation or not with carbohydrases. The chemical composition found for DRC in natural matter was 89.86% dry matter, 0.98% crude protein, 3519kcal kg-1 gross energy, 0.19% ether extract, 27% neutral detergent fiber, 19.5% of acid detergent fiber, 0.33% of calcium, 0.43% of phosphorus, 0.46% of potassium and 0.12% of magnesium. The use of carbohydrase resulted in an increase of 173 and 213kcal kg-1 in EMA and EMAn values, respectively, resulting in 1828kcal kg-1 EMA and 1840kcal kg-1 EMAn. It was concluded that the highest levels of AME and AMEn were found for the mean inclusion level of the DRC of 35% and that enzymatic supplementation may promote the increase of these parameters by up to 12% in broiler diets in the growth phase.

The objective was to evaluate increasing levels of dried brewers' grains (DBG) in feed for broiler chickens from 1 to 21 days old and their effect on performance, blood parameters, intestinal morphometry, carcass characteristics and meat quality. The design was completely randomized with six treatments, which consisted of various levels of DBG inclusion, namely 0 (no inclusion), 20, 40, 60, 80, and 100 g/kg with seven replications and 17 animals per experimental unit, totalling 714 male broilers. Performance parameters, blood biochemical profile, morphology of the intestinal epithelium (duodenum), and carcass yield and composition were evaluated. Feed intake was not changed by DBG inclusion levels. Nor were weight gain and feed conversion ratio. Serum cholesterol levels were not influenced, and there were no effects on triglyceride, uric acid and creatinine levels. Enzyme aspartate aminotransferase showed a quadratic effect, as did alanine aminotransferase, with higher values at 79.5 and 63.9 g/kg DBG inclusion, respectively. No changes in carcass yield and relative organ weight were observed. The composition of the carcass in ether extract showed a quadratic effect, as fat deposition rate, with lowest values at 62.8 and 62.4 g/kg of DBG inclusion levels, respectively. Crude protein levels in carcass reduced linearly, as did fat deposition rate. The parameters of intestinal morphology and meat quality were not changed. Dried brewers' grains can be included in broiler diet from 1 to 21 days at levels up to 100 g/kg without influencing the metabolic parameters and broiler performance.

The objective of this study was to evaluate the effects of various geometric mean diameters (GMDs) of particles of corn, pelleted soybean meal and a corn-soy mixture in the proportion of 70% and 30%, respectively, on the nutritional value of the feeds. The study evaluated energy consumption, the contents of apparent metabolizable energy (AME) and AME corrected for nitrogen balance (AMEn) and the metabolizability coefficients for broiler chickens at various ages. A total of 540 Cobb 500 male broilers were housed in metabolic cages (experimental units). Trials were performed separately with each feed. A completely randomized design was used with four treatments, namely corn with 573, 636, 851, and 1012 μm GMDs; pelleted soybean meal with 538, 550, 665, and 741 μm GMDs; and the corn-soy mixture with 627, 658, 893, and 1040 μm GMDs. Birds were evaluated on days 1 - 10, 11 - 20, 21 - 30, and 31 - 40. Larger GMDs resulted in lower energy consumption. From 1 to 10 days, birds consumed less metabolizable energy than older birds. Birds fed corn from days 1 to 10 had higher metabolizable energy (P <0.05) with increasing GMD up to 1042 μm. However, the results varied, depending on the feed and its combinations. The use of coarse particles could reduce the costs of grinding, and would have few effects on the metabolizable energy of broiler chickens.

RESUMO Objetivou-se avaliar as características dos tibiotarsos de frangos de corte fêmeas. As variáveis analisadas foram os pesos in natura, secos e desengordurados, o comprimento, os diâmetros, a resistência óssea, o índice de Seedor (IS), os percentuais de proteínas colagenosas (PC), as proteínas não colagenosas (PNC), os minerais (cálcio, fósforo, potássio e sódio) e as cinzas. Foram utilizadas 648 aves, da marca comercial Cobb®, em um delineamento em blocos ao acaso, com seis tratamentos e seis repetições, com 18 aves por unidade experimental. Os tratamentos consistiram na suplementação de 0,00; 0,50; 1,00; 1,50; 2,00 e 2,50 μg de 1,25-dihidroxivitamina-D3 (1,25(OH)2D3)/kg de ração. Aos 21 e 35 dias de idade, as aves foram pesadas e uma ave por unidade experimental (UE) com o peso médio da UE foi eutanasiada para a obtenção dos tibiotarsos e subsequente análise dos parâmetros ósseos. As variáveis métricas, bem como a composição orgânica (PC), a densidade (IS) e a resistência à quebra dos ossos das aves, não foram influenciadas pelos tratamentos. No recebimento de 2,50 µg de 1,25(OH)2D3/kg de ração, observou-se maior retenção mineral (cinzas) nos ossos das aves aos 35 dias de idade.

ABSTRACT This study aimed to evaluate the characteristics of tibiotarsus of female broilers. The variables analyzed were the weights in natura, dry and degreased, length, diameter, bone strength, Seedor index, percentage of collagenous protein (CP), non-collagenous proteins (NCP), minerals (calcium, phosphorus, potassium and sodium), and ash. Six hundred forty-eight, Cobb® birds were used, a design of randomized blocks with six treatments and six replicates of 18 birds each. The treatments consisted of supplementation of 0.00; 0.50; 1.00; 1.50; 2.00 to 2.50 µg of 1,25-dihydroxyvitamin-D3 (1,25(OH)2D3)/kg of ration. At 21 and 35 days of age the birds were weighed and a unit/experimental unit (EU) with the EU average weight was euthanized to obtain the tibiotarsos and subsequent analysis of the bone parameters. The metric variables, as well as the organic composition (CP), density (IS) and resistance to breakage of the bones of the birds were not affected by treatments. Upon reception of 2.50 µg of 1,25(OH)2D3/kg ration, there was a higher mineral retention (ashes) in the bones of female broilers at 35 days of age.

RESUMO Foi conduzido um ensaio de digestibilidade para determinar o valor nutritivo do resíduo desidratado de cervejaria (RDC) e outro para verificar o desempenho de coelhos em crescimento alimentados com rações contendo diferentes níveis de RDC e a viabilidade econômica da utilização do RDC. No ensaio de digestibilidade, foram utilizados 20 coelhos, de ambos os sexos, da raça Nova Zelândia Branco, com idade média de 45 dias, distribuídos em delineamento experimental inteiramente ao acaso, com dois tratamentos, sendo uma dieta referência e outra dieta teste, na qual o RDC substituiu a ração referência em nível de 30%. Os coeficientes de digestibilidade aparente (CDA) da matéria seca (MS), da energia bruta (EB), da proteína bruta (PB) do RDC foram de 49,97%, 49,34%, e 71,06%, respectivamente, com valores de energia digestível (ED) e proteína digestível (PD) do RDC, com base na matéria seca, de 2330,60kcal/kg e 15,75%. No experimento de desempenho, foram avaliadas rações com níveis de inclusão de RDC de 0%, 5%, 10%, 15%, 20% e 25%. Foram utilizados 120 coelhos da raça Nova Zelândia Branco, 60 machos e 60 fêmeas, com 32 dias de idade, em delineamento experimental inteiramente ao acaso, com seis tratamentos e 10 repetições, sendo a unidade experimental constituída por dois animais. Não foram observadas diferenças no desempenho dos coelhos alimentados com ração contendo níveis crescentes de RDC, exceto para a conversão alimentar aos 70 dias, que apresentou efeito quadrático no período dos 32 aos 70 dias de idade, com a pior conversão alimentar ao nível de 16,95% de RDC. No entanto, houve redução linear nos custos com alimentação, por quilo de ganho de peso dos animais. Conclui-se que o resíduo desidratado de cervejaria apresenta CDA equivalente aos ingredientes convencionais, podendo ser incluído até o nível máximo estudado de 25% nas rações de coelhos em crescimento, sem prejudicar o desempenho.

ABSTRACT Two experiments were conducted, being a digestibility assay in order to determine the nutritive value of dehydrated diets containing different levels of DBR, and the economic viability of the use of DRC brewer residue (DBR) and other assays to verify the performance of growing rabbits fed. In the digestibility experiment, twenty White New Zealand rabbits were used, with an average age of 45 days, of both genders, distributed in a completely randomized design with four treatments, one reference diet and other test diets, in which the DBR replaced the basal diet at 30% level. The apparent digestibility coefficients (ADC) of dry matter (DM), gross energy (GE), crude protein (CP) of DBR were, respectively, 49.97%, 49.34% and 71.06%. The values of digestible energy (DE) and digestible protein (DP) of the DBR, based on dry matter, were 2330.60kcal/kg and 15.75%. In the performance experiment, diets with levels of DBR inclusion of 0%, 5%, 10%, 15%, 20% and 25% were evaluated. One hundred and twenty 32 days old New Zealand White rabbits were used, being 60 males and 60 females, distributed in a completely randomized design with six treatments and ten replicates, and the experimental unit consisted of two animals. No differences (P>0.05) were observed in the performance of rabbits fed diets containing increasing levels of dehydrated brewer residue, except for feed conversion at 70 days which presented a quadratic effect, with the worst results at the level of 16.95% of the DBR inclusion in the diet. It is concluded that the dehydrated brewer residue has good nutritional value and can be included up to the maximum level studied of 25% in the diets of growing rabbits, with no damage to its performance.

Um experimento foi realizado para avaliar o efeito da utilização de diferentes promotores de crescimento sobre o metabolismo de frangos de corte em crescimento. Foram avaliadas duas dietas, uma atendendo às exigências nutricionais de frangos de corte (normal) e uma dieta reduzida, com 5% a menos da exigência nutricional (reduzida), suplementadas ou não com antibióticos e prebióticos. Foram utilizados 180 pintos de corte criados em galpão convencional, com cama de maravalha, até os 21 dias de idade. Em seguida, foram divididos em 36 gaiolas, distribuídos em delineamento experimental inteiramente ao acaso, utilizando método tradicional de coleta de excretas. Houve interação (P<0,05) entre dieta e promotores de crescimento para os coeficientes de digestibilidade ileal da matéria seca (CDIMS), da proteína bruta (CDIPB) e do extrato etéreo (CDIEE). A dieta reduzida contendo antibiótico apresentou menor CDIMS. A dieta normal contendo antibiótico apresentou maior CDIPB (P<0,05), enquanto a dieta reduzida contendo prebiótico apresentou melhor CDIPB e CDIEE (P<0,05). Os valores dos coeficientes de digestibilidade total da matéria seca (CDTMS), da proteína bruta (CDTPB) e do extrato etéreo (CDTEE) apresentaram interação (P<0,05) entre dietas e promotores de crescimento, em que a dieta reduzida contendo antibiótico apresentou menor CDTMS e CDTEE. A dieta normal apresentou maiores valores de energia metabolizável aparente (EMA) e EMA corrigida para balanço de nitrogênio (EMAn) (P<0,05). Concluiu-se que, ao se reduzir a exigência nutricional da ração, a digestibilidade dos nutrientes foi reduzida, no entanto os óleos essenciais promoveram aumento nos coeficientes de digestibilidade ileal da matéria seca, da proteína bruta e do extrato etéreo.

An experiment was conducted to evaluate the effect of using different growth promoters on the metabolism of growing broilers. We evaluated two diets, one meeting the nutritional requirements of broilers (normal) and another reduced diet with 5% less than the nutritional requirement (reduced), supplemented or not with antibiotics and prebiotics. A total of 180 broiler chicks reared in shed masonry and wood shaving bedding until 21 days of age. The animals were divided into 36 cages and distributed in a completely randomized design, using a traditional method of excreta collection. There was an interaction (P<0.05) between diet and growth promoters for ileal digestibility coefficient of dry matter (IDCDM), crude protein (IDCCP) and ether extract (IDCEE). The reduced diet containing antibiotics had lower IDCDM. The normal diet containing antibiotic had higher IDCCP (P<0.05), whereas the reduced diet containing prebiotic showed better IDCCP and IDCEE (P<0.05). The values of total digestibility coefficient of dry matter (TDCDM), crude protein (TDCCP) and ether extract (TDCEE) showed interaction (P<0.05) between diets and growth promoters, where the reduced diet containing antibiotics had lower TDCDM and TDCEE. A normal diet had higher apparent metabolizable energy (AME) and AME corrected for nitrogen balance (AMEn) (P<0.05). It was concluded that when the nutritional requirement of diet was reduced, the nutrients digestibility was also reduced, however essential oils caused an increase in ileal digestibility of dry matter, crude protein and ether extract.

Com o objetivo de determinar a exigência de lisina digestível para poedeiras semipesadas no período de 50 a 66 semanas de idade, foi realizado experimento utilizando-se 150 poedeiras Shaver Brown, distribuídas em delineamento inteiramente ao acaso, com cinco tratamentos (níveis de lisina digestível: 0,79; 0,82; 0,85; 0,88 e 0,91%), seis repetições e cinco aves por unidade experimental. Foram avaliados a produção de ovos, peso médio e a massa de ovos, consumo de ração e de lisina, conversão alimentar por massa e por dúzia de ovos, gravidade específica, unidade Haugh, o índice de gema e albúmen, porcentagem de albúmen, gema e casca. O consumo de ração, a conversão alimentar por massa e dúzia de ovos, a produção, o peso e a massa de ovos não foram influenciados (P>0,05) pelos níveis de lisina digestível. Houve aumento linear no consumo de lisina (P<0,01) com o incremento dos níveis desse aminoácido nas rações. As porcentagens de albúmen, gema e casca não foram influenciadas (P>0,05) pelos níveis de lisina digestível estudados. Os níveis de lisina influenciaram de forma quadrática (P>0,05) a unidade Haugh e o índice de albúmen, sendo estimados os níveis de 0,884 e 0,868% de lisina digestível, respectivamente. Para o índice de gema, a associação do modelo quadrático ao Linear Response Plateau (LRP) estimou o nível de 0,903% de lisina digestível. Quando o objetivo é maximizar a qualidade interna dos ovos, recomenda-se o nível dietético de 0,884%, 0,868% e 0,903% de lisina digestível para unidade Haugh, índice de albúmen e índice de gema, respectivamente.

ABSTRACT With the objective of determining the requirement of digestible lysine for brown-egg laying hens in the period from 50 to 66 weeks of age, an experiment was carried out using 150 Shaver Brown laying hens, distributed in a completely randomized design, with five treatments (digestible lysine levels: 0.79, 0.82, 0.85, 0.88 and 0.91%), six replications and five birds per experimental unit. The production of eggs, weight and the egg mass, feed intake and lysine, feed mass and dozen eggs, specific gravity, Haugh unit, yolk and albumen index, percentage of albumen, yolk and bark were analyzed. Feed intake, feed conversion per dozen of eggs s and per egg mass, egg production, egg weight and egg mass were not influenced (P>0.05) by digestible lysine levels. There was a linear increase in lysine intake (P<0.01) with increasing levels of this amino acid in the diets. The albumen, yolk and shell percentages were not influenced (P>0.05) by studied digestible lysine levels. Lysine levels had a quadratic effect (P>0.05) Haugh unit and albumen index being estimated as 0.884 and 0.868% digestible lysine levels, respectively. For yolk index, the association of the quadratic model to Linear Response Plateau (LRP) estimated the level of 0.903% digestible lysine. When the aim is to maximize the internal egg quality, a dietary level of 0.884%, 0.868% and 0.903% digestible lysine for Haugh unit, albumen index and yolk index, respectively is recommended.

Twenty crossbred castrated barrows, averaging 22.26 ± 1.79 kg of body weight, were used. The animals were individually alloted in metabolic cages, in a randomized blocks design, with five treatments (0.45, 0.52, 0.59, 0.66 and 0.73 % of digestible isoleucine) and four replicates. The diets were based on corn and soybean meal with low crude protein (14.15 %) and different levels of digestible isoleucine. The diets were humidified and supplied twice a day (7 am and 7 pm) to reduce losses and facilitate ingestion. The experimental period lasted 12 days, being 7 days for adaptation to metabolic cages and experimental diets and 5 days for total feces and urine collection. Feces were analyzed for dry matter and nitrogen (N), whereas urine samples were analyzed for N. The plasma urea nitrogen was also determined. Then, the N intake, N excretion (feces and urine), N absorbed, N retention, N retention/N intake, N retention/N absorbed and total N excretion were determined. Only N intake (g/kg BW0.75/day) was influenced (p<0.05) by digestible isoleucine levels, showing a linear increase on N intake as digestible isoleucine levels increased in the diets.

Foram utilizados vinte suínos mestiços, machos castrados, com peso vivo inicial médio de 22,26 ± 1,79 kg; distribuídos individualmente em gaiolas de metabolismo, em um delineamento experimental de blocos ao acaso, com cinco tratamentos (0,45; 0,52; 0,59; 0,66; 0,73 % de isoleucina digestível) e quatro repetições. As dietas foram formuladas à base de milho e farelo de soja, com baixa proteína bruta (14,15 %), e diferentes níveis de isoleucina digestível. As dietas foram umedecidas e fornecidas duas vezes ao dia (7 e 19 h) para reduzir perdas e facilitar a ingestão. O período experimental teve duração de 12 dias, sendo 7 dias para adaptação às gaiolas metabólicas e rações experimentais e 5 dias de coleta total de fezes e urina. Posteriormente, foi determinado o teor de matéria seca das fezes e o teor de nitrogênio (N) das fezes e urina, bem como o nitrogênio da uréia plasmática. Foram, então, calculados o consumo de N, excreção de N (fezes e urina), N absorvido, N retido, N absorvido/N retido, N retido/N consumido, N retido/N absorvido e excreção total de N. Obteve-se significância (p<0,05) apenas para o nitrogênio ingerido (g/kg PV0.75/dia), em que o modelo linear apresentou aumento nos valores de N ingerido à medida que aumentaram os níveis de isoleucina digestível nas rações.