RESUMO: Para avaliar níveis de inclusão e o efeito residual de dietas contendo extrato de levedura (ExL) associado ao plasma sanguíneo (PS) sobre o desempenho de leitões dos 36 aos 60 dias, foram utilizados 105 leitões (8,75±0,72kg), distribuídos em delineamento experimental de blocos ao acaso com cinco tratamentos (controle - 2,0% de PS; 1,0% PS, associado ao 0; 1,0; 2,0 ou 3,0% de ExL), sete repetições e três animais por unidade experimental. As dietas experimentais foram fornecidas dos 36 aos 49 dias e, dos 50 aos 60 dias de idade, os animais passaram a receber dieta única para avaliar o efeito residual dos tratamentos experimentais. Não foram observados efeitos dos tratamentos (P>0,10) sobre as variáveis de desempenho dos 36 aos 49 dias de idade. Dos 50 aos 60 dias de idade, houve efeito dos níveis de ExL sobre o consumo de ração diário (P<0,03), ganho de peso diário (P<0,01) e peso final (P<0,06) que aumentaram de forma quadrática até os níveis de 1,67, 1,67 e 1,55% de ExL, respectivamente. Leitões alimentados com a dieta contendo 1,0% de PS + 2,0% de ExL apresentaram melhor (P<0,01) conversão alimentar em relação à dieta controle (2% de PS). Por proporcionar melhor efeito residual, a inclusão de 1,67% de extrato de levedura pode substituir 50% do plasma sanguíneo na dieta de leitões dos 36 aos 49 dias de idade.

ABSTRACT: To evaluate inclusion levels and residual effects of diets containing yeast extract (YE) plus blood plasma (BP) on the performance of 36 to 60-days old piglets, 105 piglets were used (8.75±0.72kg), and they were distributed under a randomized block experimental design with five treatments (control - 2.0% BP; 1.0% BP plus 0.0, 1.0, 2.0, or 3.0% YE), seven repetitions, and three animals per experimental unit. Piglets were given experimental diets from 36 to 49 days of age. From 50 to 60 day of age, all piglets received the same diet. No effects from treatments (P>0.10) were observed on the performance variables from 36 to 49 day of age. From 50 to 60 day of age, an effect was observed from YE levels on the daily feed consumption (P<0.03), daily weight gain (p<0.01), and final weight (P<0.06), which increased quadratically up to 1.67, 1.67, and 1.55% YE levels, respectively. Piglets which were fed with the diet containing 1.0% BP + 2.0% YE were observed to have better feed conversion ratios (P<0.01) as compared to the control diet (2.0% BP). As it provides a better residual effect, the inclusion of 1.67% yeast extract may replace 50% of blood plasma in 36 to 49-days old piglet diets.

The objective of this study was to evaluate the inclusion of yeast extract as a partial replacemer of blood plasma in piglet diets and its effect on the performance and intestinal morphometry of pigs weaned at 21 days of age. One hundred and twenty animals were randomized into blocks, with five diets (4.0% blood plasma; 2.0% blood plasma with 0.0; 1.0; 2.0 or 3.0% yeast extract), six replicates and four pigs per experimental unit. At 35 days of age, one pig per experimental unit was slaughtered in order to evaluate duodenal and jejunal morphometry. The levels of yeast extract had a quadratic impact on daily feed intake and final weight, which increased up to the estimated level of 1.91%. Daily weight gain and feed conversion rate were not affected. A comparison between diets containing different levels of yeast extract and the basal diet showed that the diets containing 2.0% and 1.0% yeast extract provided the highest final weight and the worst feed conversion rate, respectively. Duodenal villus height and crypt depth were quadratically affected by yeast extract levels and the best results were achieved with the estimated levels of 1.64 and 1.16%, respectively. The levels of yeast extract provided a linear increase in the duodenal villus:crypt ratio, but did not change the morphometric variables of the jejunum. No difference was found in the morphometric variables of the duodenum and jejunum when diets containing different levels of yeast extract were compared with the basal diet. The results suggest that the inclusion of 1.91% yeast extract allows for a partial replacement for plasma in the diet, decreasing plasma inclusion from 4.0 to 2.0%.

With the objective to evaluate levels of available phosphorus (aP) in diets with or without ractopamine, 112 gilts with high genetic potential for meat deposition with initial weigh of 94.0±2.28 kg were allotted in a completely randomized block design, in a 4 × 2 factorial arrangement (0.109, 0.209, 0.309, and 0.409% aP and 0 or 5 ppm of ractopamine), with eight treatments, seven replicates, and two gilts per experimental unit. There were no interactions between aP levels and ractopamine. The levels of available phosphorus influenced both daily weight gain and daily phosphorus intake, which increased linearly. Feed conversion improved in a quadratic way up to the estimated level of 0.330% aP maximum response. Daily weight gain increased and feed conversion improved by adding ractopamine to the diets. Serum alkaline phosphatase activity decreased linearly by increasing the levels of available phosphorus. Bone strength, ash, calcium, and phosphorus contents in the bones also increased quadratically with maximum responses at 0.320, 0.270, 0.277, and 0.295% aP, respectively. The available phosphorus level of 0.330%, corresponding to a daily intake of 8.67 g of aP is suitable for 94 to 125 kg gilts selected for meat deposition fed diets with or without ractopamine.

O experimento foi conduzido com o objetivo de avaliar a influência que diferentes relações treonina:lisina digestíveis e suplementação ou não de glicina exercem sobre o desempenho de frangos de corte na fase inicial. Foram utilizados 560 pintos de corte, machos, da linhagem Cobb, distribuídos em delineamento inteiramente casualisado, em arranjo fatorial 3 x 2 +1, sendo três relações de treonina:lisina digestíveis (55; 65 e 75%), suplementados ou não com glicina mais um adicional, que continha proteína de origem animal, com relação treonina:lisina digestíveis de 65%. Utilizaram-se oito repetições e 10 aves por unidade experimental. O consumo de ração, o ganho de peso e a conversão alimentar não foram influenciados pelos níveis de treonina. A suplementação de glicina reduziu o consumo de ração, aumentou o ganho de peso e melhorou a conversão alimentar das aves. Não houve interação entre os níveis de treonina e a suplementação de glicina sobre o desempenho das aves. A suplementação de glicina foi essencial para melhorar o desempenho de pintos de corte. Concluise que a relação de 55% de treonina digestível: lisina digestível (0,631% de treonina digestível), suplementada com glicina é suficiente para atender as exigências de pintos de corte de 8 a 21 dias de idade.

The experiment was conducted with the objective evaluating the different digestible threonine: digestible lysine ratio and supplementation or not of glycine on the performance of broilers in the period from eight to 21 days of age. Five hundred and sixty male broiler chicks of the Cobb strain were used, distributed in a completely randomized design, in a factorial arrangement of 3 x 2 + 1, with three digestible threonine:lysine ratio (55, 65 and 75%), supplemented or not with glycine plus an additional treatment, containing animal protein, with digestible threonine:lysine ratio of 65%. Eight replicates were used per treatment and 10 birds were used per experimental unit. The feed intake, the weight gain and the feed conversion were not influenced by the levels of threonine. The supplementation of glycine reduced the feed intake, increased the weight gain and improved the feed conversion of the birds. There was no interaction between the levels of threonine and the supplementation of glycine on the broilers performance. The supplementation of glycine was essential to improve the broiler chicks performance. The digestible threonine: lysine ratio of 55% (0.631% of digestible threonine), supplemented with glycine is sufficient to meet the requirements of broiler chicks from 8 to 21 days of age.

Este estudo foi realizado com o objetivo de avaliar níveis de zeólita em dietas para suínos e seus efeitos no desempenho, nas características de carcaça e nos parâmetros sanguíneos e histopatológicos do parênquima hepático desses animais nas fases de crescimento e terminação. Foram utilizados 84 suínos machos castrados, híbridos comerciais de alto potencial genético para deposição de carne, com peso inicial de 30,34±1,14 kg, distribuídos em delineamento experimental de blocos ao acaso, com sete níveis de adsorvente (0,0-0,0; 1,0-0,5; 1,0-1,0; 2,0-1,0; 2,0-2,0; 3,0-1,5; 3,0-3,0, respectivamente, nas fases de crescimento e terminação), com seis repetições e dois animais por baia (unidade experimental). Utilizou-se o sorgo como fonte de contaminação natural por micotoxinas. Os níveis de adsorvente das dietas experimentais foram obtidos a partir da inclusão de zeólita em substituição à areia lavada das dietas sem adsorvente. Não houve efeito dos níveis de zeólita nas dietas sobre o consumo diário de ração, o ganho de peso diário, a conversão alimentar e as características carcaça avaliadas. Os níveis de zeólita nas dietas também não influenciaram os parâmetros sanguíneos e histopatológicos nem os teores ósseos de cálcio e fósforo dos suínos. Devido ao bom índice de desempenho e às características de carcaça, bem como à normalidade dos outros parâmetros estudados dos animais que receberam dieta sem adsorvente, pode-se inferir que as dietas continham baixo grau de contaminação por micotoxinas. Os níveis de zeólita avaliados não influenciam o desempenho, as características de carcaça nem os parâmetros sanguíneos e histopatológicos do parênquima hepático de suínos nas fases de crescimento e terminação recebendo dietas com baixo nível de contaminação por micotoxinas.

This study was conducted to evaluate levels of inclusion of zeolite in diets for pigs on performance, carcass characteristics, blood and liver histopathological parameters of these animals in their growing-finishing phases. Eighty-four barrows from commercial hybrids of high genetic potential for meat deposition, with initial weight of 30.34±1.14 kg were distributed in randomized blocks design, with seven levels of adsorbent (0.0-0.0; 1.0-0.5; 1.0-1.0; 2.0-1.0; 2.0-2.0; 3.0-1.5; 3.0-3.0, respectively, on growing and finishing phases), six replicates with two animals per pen, which was considered the experimental unit. Sorghum was used as naturally contaminated source of mycotoxins. The different levels of adsorbent in the diets were obtained by the supplementation of zeolite in the basal diet. The inclusion of zeolite in the diet did not affect the daily feed intake, daily weight gain, feed conversion or the carcass characteristics of the pigs. In the same way blood parameters, liver histopathological examination and the bone concentration neither calcium nor phosphorus were affected by the different levels of zeolita. Due to the good performance and carcass characteristics, as well as the normality of the other parameters of the animals fed diets without adsorbents analyzed, it can be inferred that the diets had low levels of mycotoxin contamination. The levels of zeolite do not affect the performance, carcass characteristics, blood parameters or liver histopathological examination in growing-finishing pigs fed diets with low level of contamination by mycotoxin.

O experimento foi conduzido com o objetivo de avaliar o efeito da suplementação de glicina em dietas com diferentes relações treonina:lisina digestíveis sobre a atividade de enzimas que metabolizam a treonina. Foram utilizados 560 pintos de corte machos, linhagem Cobb, durante o período de 8 a 21 dias de idade, distribuídos em delineamento inteiramente casualizado, num arranjo fatorial 3 × 2 + 1, composto de três relações treonina:lisina digestíveis (55; 65 e 75%), com suplementação ou não de glicina, mais um tratamento adicional, contendo farinha de carne e ossos e com relação treonina:lisina digestíveis de 65%. Utilizaram-se oito repetições por tratamento e 10 aves por unidade experimental alojadas em baterias metálicas. Procedeu-se à coleta total de excretas durante toda a fase experimental. Para determinação da atividade das enzimas treonina aldolase, treonina desidrogenase e treonina desidratase, foram abatidas no final do experimento duas aves por unidade experimental para retirada do fígado. As relações treonina:lisina influenciaram a atividade das três enzimas no fígado: a maior atividade de treonina aldolase foi para a relação de 75%; a de treonina desidrogenase para a relação de 65%, e a de treonina desidratase para a relação de 55%. A suplementação de glicina reduz a atividade de todas as enzimas avaliadas.

The experiment was conducted with the objective evaluating the effect of supplementation of glycine in diets with different digestible threonine:digestible lysine ratios on the activity of enzymes that metabolize threonine. Five hundred and sixty male broiler chicks from the Cobb strain were used during the period of 8 to 21 days, distributed in a completely randomized design, in a 3 × 2 + 1 factorial arrangement, with 3 digestible threonine:digestible lysine ratios (55; 65 and 75%), with or without supplementation of glycine, plus an additional treatment, containing meat and bone meal, with a 65% digestible threonine:digestible lysine ratio. Eight repetitions were used per treatment and 10 birds per experimental unit, allotted in metal battery cages. The total excreta collection was performed throughout the whole experimental stage. For the determination of the activity of the threonine aldolase, threonine dehydrogenase and threonine dehydratase enzymes, at the end of the experiment, two birds were slaughtered and had their livers extracted. The threonine:lysine ratios influenced the activity of the three enzymes in the liver; while the greatest activity of the threonine aldolase was for the ratio of 75%, for threonine dehydrogenase it was 65%, and for the threonine dehydratase it was 55%. Supplementation of glycine reduced the activity of all enzymes evaluated.