Effects of a monocomponent protease from Bacillus licheniformis on broiler performance, digestibility, and carcass yield

Two experiments were carried out to evaluate the effectsof protease addition to the diet of broilers at a higher level (1× or 2×) thanthe nutritional value proposed for the enzyme. The first experiment, 1280 day-old chicks (Cobb500®) were randomly allocated (randomized block design, 2×2+1 factorial arrangement),five treatments, eight replicates containing32 birds/replicate. Treatmentsconsisted: control diet without protease (CD); CD + 1× nutritional value of the enzyme (CDM1); CD + 2× nutritional value of the enzyme (CDM2); CDM1 + protease; and CDM2 + protease. The experimental period was 42 days. The mean weight (AFW), feed intake (FI), weight gain (WG), feed conversion, and carcass yield were evaluated. Significant differences were observed for AFW, WG, FI, abdominal fat yield, and feet percentage in the carcass. In the second experiment, 120 Cobb500®chicks at 14 days of age were allotted in a completely randomized design, 2×2+1 factorial arrangement, five treatments, six replicates withfour birds/replicate. The treatments were consistent with the first experiment. Significant improvements in the nitrogen balance wereobserved for the broilersthat received protease.The use of the enzyme tested is recommended with the recommended nutritional matrix, improving the zootechnical indices of broilers.(AU)

Environment type and storage period on eggshell quality of laying hens at different ages / Tipos de ambiente e período de armazenamento sobre a qualidade de casca de ovos de poedeiras comerciais em diferentes idades

Eggshell quality is directly linked to the good acceptability of the product by consumers, whereas the industry is concerned with economic losses. Prolonged periods of laying, diseases, nutrition, bird age and genetics can influence egg quality. This study aimed to examine the influence of the environment, bird age and storage period on the physical characteristics of the shell of eggs from commercial laying hens. The experiment involved 288 eggs from Hy-line hens, which were distributed in a completely randomized design with a triple 3×2×4 factorial arrangement represented by three ages (31, 62 or 88 weeks), two storage temperatures (ambient or refrigerated), and four storage periods (one, 10, 20 or 30 days), totaling 24 treatments. Four replications were used with three eggs each. Eggshell strength, percentage and thickness were measured. Differences were observed, with the eggs stored at room temperature exhibiting lower shell strength. Laying eggs at an advanced age (88 weeks) resulted in decreased eggshell strength as compared with the other ages, whereas the eggs from young layers (31 weeks) had a thicker shell. The advancing age of the laying hens reduced eggshell quality, regardless of the storage environment. Nonetheless, the eggs stored in the refrigerator showed better eggshell quality and integrity than those stored at ambient temperature.

A qualidade da casca está diretamente ligada à boa aceitabilidade do produto pelos consumidores, enquanto a indústria se preocupa com as perdas econômicas. Períodos prolongados de postura, doenças, nutrição, idade da ave e genética podem influenciar a qualidade dos ovos. Objetivou-se avaliar a influência do ambiente, idade da ave e período de armazenamento nas características físicas da casca de ovos de poedeiras comerciais. Foram utilizados 288 ovos de poedeiras Hy-line, distribuídos em um delineamento inteiramente casualizado em fatorial triplo 3x2x4, sendo os fatores: três idades (31, 62 e 88 semanas), temperatura de armazenamento (ambiente e refrigerado), e quatro períodos de armazenamento (um, 10, 20 e 30 dias), totalizando 24 tratamentos, com quatro repetições de três ovos. Avaliou-se a resistência, percentual e espessura da casca. Foram observadas diferenças, uma vez que os ovos armazenados em temperatura ambiente apresentaram diminuição na resistência de casca. Ovos de poedeiras em idade avançada (88 semanas) apresentaram pior resistência de casca em relação às demais idades, enquanto ovos provenientes de poedeiras jovens (31 semanas) apresentaram maior espessura de casca. A idade avançada da poedeira reduziu a qualidade de casca dos ovos, independentemente do ambiente de armazenamento. Ainda, os ovos armazenados em geladeira apresentaram melhor qualidade e integridade da casca em comparação com os armazenados ao ambiente.

Environment type and storage period on eggshell quality of laying hens at different ages / Tipos de ambiente e período de armazenamento sobre a qualidade de casca de ovos de poedeiras comerciais em diferentes idades

ABSTRACT: Eggshell quality is directly linked to the good acceptability of the product by consumers, whereas the industry is concerned with economic losses. Prolonged periods of laying, diseases, nutrition, bird age and genetics can influence egg quality. This study aimed to examine the influence of the environment, bird age and storage period on the physical characteristics of the shell of eggs from commercial laying hens. The experiment involved 288 eggs from Hy-line hens, which were distributed in a completely randomized design with a triple 3×2×4 factorial arrangement represented by three ages (31, 62 or 88 weeks), two storage temperatures (ambient or refrigerated), and four storage periods (one, 10, 20 or 30 days), totaling 24 treatments. Four replications were used with three eggs each. Eggshell strength, percentage and thickness were measured. Differences were observed, with the eggs stored at room temperature exhibiting lower shell strength. Laying eggs at an advanced age (88 weeks) resulted in decreased eggshell strength as compared with the other ages, whereas the eggs from young layers (31 weeks) had a thicker shell. The advancing age of the laying hens reduced eggshell quality, regardless of the storage environment. Nonetheless, the eggs stored in the refrigerator showed better eggshell quality and integrity than those stored at ambient temperature.

RESUMO: A qualidade da casca está diretamente ligada à boa aceitabilidade do produto pelos consumidores, enquanto a indústria se preocupa com as perdas econômicas. Períodos prolongados de postura, doenças, nutrição, idade da ave e genética podem influenciar a qualidade dos ovos. Objetivou-se avaliar a influência do ambiente, idade da ave e período de armazenamento nas características físicas da casca de ovos de poedeiras comerciais. Foram utilizados 288 ovos de poedeiras Hy-line, distribuídos em um delineamento inteiramente casualizado em fatorial triplo 3x2x4, sendo os fatores: três idades (31, 62 e 88 semanas), temperatura de armazenamento (ambiente e refrigerado), e quatro períodos de armazenamento (um, 10, 20 e 30 dias), totalizando 24 tratamentos, com quatro repetições de três ovos. Avaliou-se a resistência, percentual e espessura da casca. Foram observadas diferenças, uma vez que os ovos armazenados em temperatura ambiente apresentaram diminuição na resistência de casca. Ovos de poedeiras em idade avançada (88 semanas) apresentaram pior resistência de casca em relação às demais idades, enquanto ovos provenientes de poedeiras jovens (31 semanas) apresentaram maior espessura de casca. A idade avançada da poedeira reduziu a qualidade de casca dos ovos, independentemente do ambiente de armazenamento. Ainda, os ovos armazenados em geladeira apresentaram melhor qualidade e integridade da casca em comparação com os armazenados ao ambiente.

Environment type and storage period on eggshell quality of laying hens at different ages / Tipos de ambiente e período de armazenamento sobre a qualidade de casca de ovos de poedeiras comerciais em diferentes idades

Eggshell quality is directly linked to the good acceptability of the product by consumers, whereas the industry is concerned with economic losses. Prolonged periods of laying, diseases, nutrition, bird age and genetics can influence egg quality. This study aimed to examine the influence of the environment, bird age and storage period on the physical characteristics of the shell of eggs from commercial laying hens. The experiment involved 288 eggs from Hy-line hens, which were distributed in a completely randomized design with a triple 3×2×4 factorial arrangement represented by three ages (31, 62 or 88 weeks), two storage temperatures (ambient or refrigerated), and four storage periods (one, 10, 20 or 30 days), totaling 24 treatments. Four replications were used with three eggs each. Eggshell strength, percentage and thickness were measured. Differences were observed, with the eggs stored at room temperature exhibiting lower shell strength. Laying eggs at an advanced age (88 weeks) resulted in decreased eggshell strength as compared with the other ages, whereas the eggs from young layers (31 weeks) had a thicker shell. The advancing age of the laying hens reduced eggshell quality, regardless of the storage environment. Nonetheless, the eggs stored in the refrigerator showed better eggshell quality and integrity than those stored at ambient temperature.(AU)

A qualidade da casca está diretamente ligada à boa aceitabilidade do produto pelos consumidores, enquanto a indústria se preocupa com as perdas econômicas. Períodos prolongados de postura, doenças, nutrição, idade da ave e genética podem influenciar a qualidade dos ovos. Objetivou-se avaliar a influência do ambiente, idade da ave e período de armazenamento nas características físicas da casca de ovos de poedeiras comerciais. Foram utilizados 288 ovos de poedeiras Hy-line, distribuídos em um delineamento inteiramente casualizado em fatorial triplo 3x2x4, sendo os fatores: três idades (31, 62 e 88 semanas), temperatura de armazenamento (ambiente e refrigerado), e quatro períodos de armazenamento (um, 10, 20 e 30 dias), totalizando 24 tratamentos, com quatro repetições de três ovos. Avaliou-se a resistência, percentual e espessura da casca. Foram observadas diferenças, uma vez que os ovos armazenados em temperatura ambiente apresentaram diminuição na resistência de casca. Ovos de poedeiras em idade avançada (88 semanas) apresentaram pior resistência de casca em relação às demais idades, enquanto ovos provenientes de poedeiras jovens (31 semanas) apresentaram maior espessura de casca. A idade avançada da poedeira reduziu a qualidade de casca dos ovos, independentemente do ambiente de armazenamento. Ainda, os ovos armazenados em geladeira apresentaram melhor qualidade e integridade da casca em comparação com os armazenados ao ambiente.(AU)

Performance, nutrient digestibility, and intestinal histomorphometry of broilers fed diet supplemented with guava extract standardized in phenolic compounds

The objective of this study was to evaluate the effects of guava extract standardized in phenolic compounds (SGE) on broiler performance, nutrient digestibility, and intestinal histomorphometry. A total of 300 one-day-old male Cobb-500® broiler chicks were distributed in a completely randomized design with five treatments (basal diet supplemented with 120 mg vitamin E/kg and basal diet supplemented with 0, 600, 800, or 1,000 mg SGE/kg) and six replicates of ten birds each. Performance was evaluated at seven and 21 days of age; digestibility of nutrients was determined by total excreta collection from 18 to 21 days of age; and histomorphometry of the small intestine was assessed at 21 days of age. Broilers fed diets supplemented with SGE or vitamin E had higher body weight and weight gain and better feed conversion than those fed unsupplemented diet at seven days of age. At the same age, there was a quadratic effect of SGE levels on body weight and weight gain, with better weights for 715 and 716 mg SGE/kg, respectively; and a decreasing linear effect for feed conversion. At 21 days of age, body weight and weight gain increased linearly with the inclusion of SGE in diet. Digestibility of feed nutrients was not influenced by treatments. Broilers fed diet supplemented with 800 or 1,000 mg SGE/kg had greater villus height and villus:crypt ratio of the duodenum than those fed unsupplemented diet. Villus height in the jejunum of broilers fed diet supplemented with 600 mg SGE/kg was lower than that of broilers that received vitamin E. Guava extract standardized in phenolic compounds can be used in diets for broilers in the starter phase, considering that the extract increases weight gain, reduces feed conversion, and helps in the development of the intestinal mucosa.

Egg characteristics of Japanese quail fed diets containing guava extract (Psidium guajavaL. )

The main purposeof this study was to evaluate the characteristics of eggs produced by Japanese quails fed with guava extract.A total of 400 eggs collected from the quails fed with experimental diets, were distributed in a completely randomized design infactorial arrangement 4x4 with main effects including four dietary levels of guava extract(0, 3, 6 and 9 gkg-1)andfour storage periods (0, 9,18 and 27 days)totalizing 16 treatmentswith five replicates of five eggs. The eggs were produced by Japanese quails, fed with experimental diets. The diets were isonutritive formulated by corn-soybean basis. The eggs were stored for different periods, at the same conditions, to constitute the treatments. Theparameters evaluated were egg weight loss(g and %), yolk color, Haugh unit, specific gravity, eggshell thickness and pH of the yolk and albumen. Datawere submitted to ANOVA, and means were compared using Scott-Knotttest, using α= 0.05.The specific gravity of fresh eggs was better with the use of 6 g kg-1of guava extract in the diet. The use of 3 g kg-1of guava extractresulted in smaller eggshell thickness of fresh eggs. The Haugh unit was affectedjust by the storage periods. The dietary guava extract (3, 6 or9 g kg-1) increased the pH of albumen ineggs stored for 27 days. The use of 6 g kg-1 of guava extract in quails diet increase thespecific gravity in fresh eggs and increase the yolk color when the eggs are stored.(AU)

Egg characteristics of Japanese quail fed diets containing guava extract (Psidium guajavaL. )

The main purposeof this study was to evaluate the characteristics of eggs produced by Japanese quails fed with guava extract.A total of 400 eggs collected from the quails fed with experimental diets, were distributed in a completely randomized design infactorial arrangement 4x4 with main effects including four dietary levels of guava extract(0, 3, 6 and 9 gkg-1)andfour storage periods (0, 9,18 and 27 days)totalizing 16 treatmentswith five replicates of five eggs. The eggs were produced by Japanese quails, fed with experimental diets. The diets were isonutritive formulated by corn-soybean basis. The eggs were stored for different periods, at the same conditions, to constitute the treatments. Theparameters evaluated were egg weight loss(g and %), yolk color, Haugh unit, specific gravity, eggshell thickness and pH of the yolk and albumen. Datawere submitted to ANOVA, and means were compared using Scott-Knotttest, using α= 0.05.The specific gravity of fresh eggs was better with the use of 6 g kg-1of guava extract in the diet. The use of 3 g kg-1of guava extractresulted in smaller eggshell thickness of fresh eggs. The Haugh unit was affectedjust by the storage periods. The dietary guava extract (3, 6 or9 g kg-1) increased the pH of albumen ineggs stored for 27 days. The use of 6 g kg-1 of guava extract in quails diet increase thespecific gravity in fresh eggs and increase the yolk color when the eggs are stored.

Use of neem (Azadirachta indica) as a substitute for antimicrobial drugs in broiler chickens’ feed / Utilização de neem (Azadirachta indica) em substituição ao antimicrobiano em rações de frangos de corte

In the present work, we carried out an experiment aiming at evaluating the use of Neem as an antimicrobial substance in the feeds of broiler chickens. We used 240 one-day-old Cobb broiler chicks distributed in an entirely casual design, with 4 treatments, 6 repetitions and 10 birds per experimental unit, during a 21-day experimental period. Treatments consisted of a basal diet with no antimicrobial inclusion, a diet with 0.05% of tylosin, and a diet with 0.05% and 0.1% of Neem. Parameters evaluated were zootechnical performance, feed digestibility, intestinal count of Salmonella sp. and Escherichia coli, and the development of lymphoid organs. Data on the performance and metabolization of nutrients were subjected to an ANOVA and averages were compared with a post-hoc Tukey test considering α=0.05. Data on E. coli counts were analyzed with a Kruskal-Wallis test. Neem did not influence performance variables. The metabolization coefficient of dry matter and feed ethereal extract was better with tylosin (P<0.05). No growth of Salmonella was observed during the experiment. The use of Neem did not reduce E. coli population and had no influence on lymphoid organs' weight. Therefore, Neem had no effect on the performance, digestibility and intestinal microbiota of birds up to 21 days old.

Realizou-se um experimento objetivando avaliar a utilização de Neem como antimicrobiano em rações de frangos de corte. Foram utilizados 240 pintos de corte, Cobb, com 1 dia de idade, distribuídos em delineamento inteiramente casualizado, 4 tratamentos, 6 repetições, 10 aves por unidade experimental, o período experimental foi de 21 dias. Os tratamentos consistiram: dieta basal sem inclusão de antimicrobiano; dieta com 0,05% de tilosina; dieta com 0,05% e 0,1% de Neem. Avaliou-se: o desempenho zootécnico, a digestibilidade da ração, contagem intestinal de Salmonella sp. e Escherichia coli, e o desenvolvimento dos órgãos linfoides. Dados de desempenho e metabolização dos nutrientes da ração foram submetidos à ANOVA, médias comparadas pelo teste Tukey, adotou-se α=0,05. Dados de contagem de E. coli foram analisados pelo teste de Kruskal-Wallis. O Neem não influenciou as variáveis de desempenho. O coeficiente de metabolizabilidade da matéria seca e extrato etéreo da ração foi melhor com utilização de tilosina (P<0,05). Não se observou crescimento de Salmonella durante o período experimental. A utilização de Neem não reduziu a população de E. coli, e não influenciou no peso dos órgãos linfoides. A utilização do Neem não afetou o desempenho, digestibilidade e microbiota intestinal das aves até 21 dias.

Use of neem (Azadirachta indica) as a substitute for antimicrobial drugs in broiler chickens feed / Utilização de neem (Azadirachta indica) em substituição ao antimicrobiano em rações de frangos de corte

In the present work, we carried out an experiment aiming at evaluating the use of Neem as an antimicrobial substance in the feeds of broiler chickens. We used 240 one-day-old Cobb broiler chicks distributed in an entirely casual design, with 4 treatments, 6 repetitions and 10 birds per experimental unit, during a 21-day experimental period. Treatments consisted of a basal diet with no antimicrobial inclusion, a diet with 0.05% of tylosin, and a diet with 0.05% and 0.1% of Neem. Parameters evaluated were zootechnical performance, feed digestibility, intestinal count of Salmonella sp. and Escherichia coli, and the development of lymphoid organs. Data on the performance and metabolization of nutrients were subjected to an ANOVA and averages were compared with a post-hoc Tukey test considering α=0.05. Data on E. coli counts were analyzed with a Kruskal-Wallis test. Neem did not influence performance variables. The metabolization coefficient of dry matter and feed ethereal extract was better with tylosin (P<0.05). No growth of Salmonella was observed during the experiment. The use of Neem did not reduce E. coli population and had no influence on lymphoid organs' weight. Therefore, Neem had no effect on the performance, digestibility and intestinal microbiota of birds up to 21 days old.(AU)

Realizou-se um experimento objetivando avaliar a utilização de Neem como antimicrobiano em rações de frangos de corte. Foram utilizados 240 pintos de corte, Cobb, com 1 dia de idade, distribuídos em delineamento inteiramente casualizado, 4 tratamentos, 6 repetições, 10 aves por unidade experimental, o período experimental foi de 21 dias. Os tratamentos consistiram: dieta basal sem inclusão de antimicrobiano; dieta com 0,05% de tilosina; dieta com 0,05% e 0,1% de Neem. Avaliou-se: o desempenho zootécnico, a digestibilidade da ração, contagem intestinal de Salmonella sp. e Escherichia coli, e o desenvolvimento dos órgãos linfoides. Dados de desempenho e metabolização dos nutrientes da ração foram submetidos à ANOVA, médias comparadas pelo teste Tukey, adotou-se α=0,05. Dados de contagem de E. coli foram analisados pelo teste de Kruskal-Wallis. O Neem não influenciou as variáveis de desempenho. O coeficiente de metabolizabilidade da matéria seca e extrato etéreo da ração foi melhor com utilização de tilosina (P<0,05). Não se observou crescimento de Salmonella durante o período experimental. A utilização de Neem não reduziu a população de E. coli, e não influenciou no peso dos órgãos linfoides. A utilização do Neem não afetou o desempenho, digestibilidade e microbiota intestinal das aves até 21 dias.(AU)

Effect of diets with different levels of guanidinoacetic acid on newly weaned piglets / Efeito de dietas com diferentes níveis de ácido guanidinoacético para leitões recém-desmamados

Ninety barrow piglets weaned at 21 days old were used to evaluate the effects of guanidinoacetic acid (GAA) supplementation on their performance and blood creatinine and creatine kinase (CK) levels during the nursery phase (21 to 63 days old). The piglets were distributed in a randomized block design with five treatments (0, 0.05, 0.10, 0.15, and 0.20% GAA inclusion), six repetitions, and three animals per repetition. The experimental rations were formulated to meet the nutritional requirements for the phases of 21 to 32, 33 to 42 and 43 to 63 days of age. The experimental diets and water were offered ad libitum throughout the experimental period. At 42 and 63 days old, blood was collected from one animal in each experimental unit for creatinine and creatine kinase analysis. The analysed variables were daily weight gain (DFG), daily feed intake (DFI), and feed conversion (FC) in the 21 to 42 days old and 21 to 63 days old of the nursery phase. All variables were subjected to analysis of variance and regression analysis. We adopted α = 0.05, and considered a trend to be present when α was between 0.05 and 0.10. In the pre-initial period (21 to 42 days old), there was an increasing trend in daily weight (P = 0.069), which increased to the level of 0.97% of GAA inclusion. The DFI and FC were not significantly affected by the addition of different GAA levels in the diet. Creatinine levels in the blood at 42 and 63 days old were not significantly influenced by the treatments. The level of CK at 42 days old showed an increasing trend (P = 0.077) that occurred quadratically to the level of 0.085% of GAA inclusion, with no significant difference for this variable at 63 days old. The use of GAA did not promote improvements in performance or blood creatinine and CK levels in piglets in the nursery phase.

Para se avaliar os efeitos do uso do ácido guanidinoacético (AGA) em rações de leitões na fase de creche (21 aos 63 dias de idade) sobre o desempenho e níveis de creatina quinase (CQ) e creatinina sanguínea, foram utilizados 90 leitões, machos castrados desmamados aos 21 dias de idade. Os leitões foram distribuídos em delineamento em blocos casualizados com cinco tratamentos (0; 0,05; 0,10, 0,15 e 0,20% de inclusão do AGA), seis repetições e três animais por repetição. As rações experimentais foram formuladas para atender as exigências nutricionais para as fases de 21 a 32, 33 a 42 e 43 a 63 dias de idade. Água e ração foram oferecidas à vontade durante todo o período experimental. Aos 42 e aos 63 dias de idade foi coletado sangue de um animal por unidade experimental para análise de creatinina e creatina quinase. Foram analisadas as variáveis de ganho de peso diário (GPD), consumo de ração diário (CDR) e conversão alimentar (CA) nos períodos chamados pré-inicial (21 a 42 dias de idade) e no período total da fase de creche (21 a 63 dias de idade). Todas as variáveis foram submetidas à análise de variância e à análise de regressão. Foi adotado α = 0,05 e foi considerado tendência quando α ocorreu entre 0,05 e 0,10. Na fase pré-inicial (21-42 dias), ocorreu tendência de aumento para o parâmetro de ganho de peso diário (P= 0,069) que aumentou até o nível de 0,97% de inclusão de AGA. O consumo de ração diário e conversão alimentar não foram influenciados significativamente pela adição de diferentes níveis de AGA na dieta. Já para as variáveis sanguíneas, os níveis de creatinina aos 42 e aos 63 dias não foram influenciados significativamente pelos tratamentos. O nível de creatina quinase aos 42 dias apresentou uma tendência (P=0,077) de aumento que ocorreu de forma quadrática até o nível de 0,085% de inclusão do AGA, não havendo diferença significativa para essa variável aos 63 dias.

Effect of diets with different levels of guanidinoacetic acid on newly weaned piglets / Efeito de dietas com diferentes níveis de ácido guanidinoacético para leitões recém-desmamados

Ninety barrow piglets weaned at 21 days old were used to evaluate the effects of guanidinoacetic acid (GAA) supplementation on their performance and blood creatinine and creatine kinase (CK) levels during the nursery phase (21 to 63 days old). The piglets were distributed in a randomized block design with five treatments (0, 0.05, 0.10, 0.15, and 0.20% GAA inclusion), six repetitions, and three animals per repetition. The experimental rations were formulated to meet the nutritional requirements for the phases of 21 to 32, 33 to 42 and 43 to 63 days of age. The experimental diets and water were offered ad libitum throughout the experimental period. At 42 and 63 days old, blood was collected from one animal in each experimental unit for creatinine and creatine kinase analysis. The analysed variables were daily weight gain (DFG), daily feed intake (DFI), and feed conversion (FC) in the 21 to 42 days old and 21 to 63 days old of the nursery phase. All variables were subjected to analysis of variance and regression analysis. We adopted α = 0.05, and considered a trend to be present when α was between 0.05 and 0.10. In the pre-initial period (21 to 42 days old), there was an increasing trend in daily weight (P = 0.069), which increased to the level of 0.97% of GAA inclusion. The DFI and FC were not significantly affected by the addition of different GAA levels in the diet. Creatinine levels in the blood at 42 and 63 days old were not significantly influenced by the treatments. The level of CK at 42 days old showed an increasing trend (P = 0.077) that occurred quadratically to the level of 0.085% of GAA inclusion, with no significant difference for this variable at 63 days old. The use of GAA did not promote improvements in performance or blood creatinine and CK levels in piglets in the nursery phase.(AU)

Para se avaliar os efeitos do uso do ácido guanidinoacético (AGA) em rações de leitões na fase de creche (21 aos 63 dias de idade) sobre o desempenho e níveis de creatina quinase (CQ) e creatinina sanguínea, foram utilizados 90 leitões, machos castrados desmamados aos 21 dias de idade. Os leitões foram distribuídos em delineamento em blocos casualizados com cinco tratamentos (0; 0,05; 0,10, 0,15 e 0,20% de inclusão do AGA), seis repetições e três animais por repetição. As rações experimentais foram formuladas para atender as exigências nutricionais para as fases de 21 a 32, 33 a 42 e 43 a 63 dias de idade. Água e ração foram oferecidas à vontade durante todo o período experimental. Aos 42 e aos 63 dias de idade foi coletado sangue de um animal por unidade experimental para análise de creatinina e creatina quinase. Foram analisadas as variáveis de ganho de peso diário (GPD), consumo de ração diário (CDR) e conversão alimentar (CA) nos períodos chamados pré-inicial (21 a 42 dias de idade) e no período total da fase de creche (21 a 63 dias de idade). Todas as variáveis foram submetidas à análise de variância e à análise de regressão. Foi adotado α = 0,05 e foi considerado tendência quando α ocorreu entre 0,05 e 0,10. Na fase pré-inicial (21-42 dias), ocorreu tendência de aumento para o parâmetro de ganho de peso diário (P= 0,069) que aumentou até o nível de 0,97% de inclusão de AGA. O consumo de ração diário e conversão alimentar não foram influenciados significativamente pela adição de diferentes níveis de AGA na dieta. Já para as variáveis sanguíneas, os níveis de creatinina aos 42 e aos 63 dias não foram influenciados significativamente pelos tratamentos. O nível de creatina quinase aos 42 dias apresentou uma tendência (P=0,077) de aumento que ocorreu de forma quadrática até o nível de 0,085% de inclusão do AGA, não havendo diferença significativa para essa variável aos 63 dias. (AU)