The addition of protease to broiler diets may complement the action of endogenous enzymes and improve protein digestibility. Here, the authors evaluated the effect of adding protease to broiler diets that contained animal-based meal on bird performance, digestibility, and biometry of digestive tract organs. Four treatments, which contained animal- or plant-based meals with or without supplementary protease were compared, namely basal vegetable feed (BVF), BVF + protease (BFP), basal vegetable feed + animal by-product meal (BFA), and BFA + protease. In the first experiment, 320 one-day-old Cobb 500® chicks were allocated to eight replicates with 10 birds per replicate. The experimental period was seven days, and nutrient metabolizability was evaluated. In the second experiment, 720 one-day-old Cobb 500® chicks were assigned to treatments in a similar manner, with six replicates and 30 birds per replicate, but the experimental period was 42 days. Significant differences (P <0.05) were observed between treatments for nutrient digestibility, weight gain, feed consumption, average final weight, food conversion, viability, and biometry of the pancreas. Treatments with animal-based meals had the highest digestibility. Birds fed these meals grew faster in the pre-starter phase and consumed less feed between 1 and 21 days. However, between 1 and 42 days old, broilers fed plant-based diets had better feed conversion, and the group that did not receive protease supplementation had a better liveability rate.Keywords: additive, exogenous enzyme, nutrition, organ biometry, poultry

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. Key words: Arginine. Creatine. Performance. Pigs. Supplementation. ResumoPara 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...

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.

-Seventy-two barrows were used to evaluate the effects of the use of soy protein concentrate (SPC) in diets of post-weaning piglets on their performance, intestinal histomorphometry, and blood parameters. Piglets were weaned at 21 days of age and distributed in a randomized-block experimental design with four treatments (0, 3, 6, and 9% SPC), six replications, and three piglets per replication. Diets were formulated to meet the requirement of the piglets according to phases of 21 to 32, 33 to 42, and 43 to 66 days of age. Both feed and water were provided ad libitum during the entire experiment. The feed of the phase of 43 to 66 days was based on corn and soybean meal. In the period between 21 and 32 days of age, the use of SPC in the diet did not impact the daily weight gain (DWG) or the daily feed intake (DFI) of the piglets, whereas there was a linear effect on feed conversion (FC), which decreased as the levels of SPC in the feed were increased. In the period between 33 and 42 days of age, a linear effect was observed on FC, which increased as the level of SPC in the feed was increased. In this period, no effects of SPC were observed on DWG or DFI. Inclusion of SPC in the diets does not influence performance, intestinal histomorphometry, or blood parameters of piglets in the period between 21 and 66 days of age.

-In this study, we evaluated the effects of substitution of partial and total spray-dried blood plasma (BP) with soy protein concentrate (SPC) in the diet of post-weaning piglets on their performance, intestinal histomorphometry, and blood parameters. Fifty-four castrated male piglets, weaned at an average age of 21 days and an initial average weight of 7.01±0.294 kg, were distributed in a completely randomized block design, with three diets (0%SPC-5%BP, 2.5%SPC-2.5%BP, and 5%SPC-0%BP), six replicates, and three piglets per experimental unit. The experimental feeds were formulated to meet the requirements of the piglets at 21-32 and 33-42 days of age (pre-starter diet) and 43-66 days of age (starter diet). From 21 to 32 and 21 to 42 days of age, daily feed intake, daily weight gain, and final weight of the animals were higher in the group fed 2.5%SPC-2.5%BP and 0%SPC-5%BP. From 21 to 66 days of age, daily weight gain and daily feed intake were higher in the animals fed 2.5%SPC-2.5%BP. No effect was observed on the histomorphometry variables. The total leukocyte count was higher in animals fed 2.5%SPC-2.5%BP and 5%SPC-0%BP and the lymphocyte count was lower in the piglets that received 0%SPC-5%BP. The combined use of soy protein concentrate and spray-dried blood plasma in the feeds of piglets between 21 and 42 days of age improves their productive performance.