Verônica Maria Pereira Bernardino

Activity of glutamate dehydrogenase and protein content in the breast of broilers fed diets containing different sources and levels of glycerine

According to scientific literature, glycerol in the diet can spare glucogenic amino acids by inhibiting the activity of enzymes, such as glutamate dehydrogenase, thereby promoting protein deposition in muscle tissues. Therefore, the objective of this study was to evaluate the effect of three sources of glycerine (crude glycerine from soybean oil--CGSO, mixed crude glycerine from frying oil and lard--MCG and a semipurified glycerine from soybean oil--SPGSO) in four concentrations in the diet (17.5, 35.0, 52.5 and 70.0 g of each type of glycerine/kg of feed) on the activity of hepatic glutamate dehydrogenase, performance and protein content in the breast of broilers, during 22-35 days of age (experiment I) and 33-43 days of age (experiment II). In both experiments, an increase in MCG induced a linear decline in glutamate dehydrogenase activity (p < 0.05). In contrast, increasing the concentration of SPGSO in the diet caused a linear increase in enzyme activity (p < 0.05). There was no (p > 0.05) isolated effect of glycerine on the enzyme activity in either evaluated phase; however, during 33-42 days of age, MCG inhibited (p < 0.05) the glutamate dehydrogenase activity by up to 34.43%. During 22-35 days of age, the diet containing SPGSO induced a higher protein content (p < 0.05) in the breast, and regardless of the source utilized, the maximum protein deposition was estimated (p < 0.05) when broilers were fed with 55.08 g glycerine/kg of diet. There was no (p > 0.05) interaction or isolated effects of the sources and levels of glycerine on the protein content in the breast of broilers at 33-42 days of age, and moreover, all diets containing glycerine promoted a similar protein deposition in the breast compared with birds that received the diet without glycerine. The bird age also showed to influence the feed intake and weight gain of broilers fed diet containing glycerine. It is concluded that for both rearing phases, an increase in glycerine in the diet did not necessarily reduce the glutamate dehydrogenase activity, and the protein deposition in the breast of broilers may not be strictly correlated with the activity of this enzyme.

Content of plasmatic glycerol and activity of hepatic glycerol kinase in broiler chickens fed diets containing different sources and concentrations of glycerine

The objective of this study was to evaluate the effect of three sources of glycerine (crude glycerine from soya bean oil - CGSO, mixed crude glycerine from frying oil and lard--MCG, and a semipurified glycerine from soya bean oil--SPGSO) in four concentrations in the diet (17.5, 35.0, 52.5 and 70.0 g of each type of glycerine per kg of feed) on the levels of plasmatic glycerol and the activity of the hepatic enzyme glycerol kinase in broilers of 22-35 days old (experiment I) and 33-42 days old (experiment II). The highest (p < 0.05) plasmatic glycerol level was detected in broilers fed diet containing CGSO. Independent of the source, increasing the concentration of glycerine led to a linear increase (p < 0.05) in the plasmatic glycerol concentration. In experiment I, all the diets containing glycerine resulted in increased concentrations of plasmatic glycerol, in relation to the control diet without glycerine. However, in experiment II, only the diet containing 17.5 g of CGSO per kg of feed and the diets formulated with any of the three types of glycerine in the inclusion concentrations of 35, 52.5 and 70 g/kg of feed resulted in higher plasmatic glycerol levels than those observed in the control broilers. The source of glycerine influenced the glycerol kinase activity only in experiment II, where the use of CGSO in the diet increased the enzyme activity. For both experiments, the glycerol kinase activity increased with the inclusion of glycerine in the diet. In conclusion, based on the absence of saturation of the glycerol kinase activity for the three glycerine sources and for both rearing periods evaluated, the broilers can metabolize the glycerol (at the level of the phosphorylation of the glycerol to glycerol-3-phosphate in the liver) present in the glycerine when the diet is supplemented with up to 70 g of glycerine per kg of feed.

Diets with reduced levels of nutrients supplemented with phytase and amino acids for broilers

Um experimento de desempenho e outro de metabolismo foram conduzidos simultaneamente com frangos de corte de 22 a 35 dias de idade, avaliando-se cinco dietas em seis repeticoes. A dieta controle, sem fitase, continha 19% de proteina bruta (PB); 0,412% de fosforo disponivel (Pdisp) e 0,824% de calcio (Ca). As demais dietas foram suplementadas com fitase e formuladas com 0,262% de Pdisp e 0,524% de Ca, tendo o teor de PB variado em 19 ate 16%. No ensaio de desempenho, 750 aves foram utilizadas, avaliando-se o desempenho, o teor de cinzas na tibia e rendimentos de carcaca, cortes e gordura abdominal, aos 35 dias de idade. O ensaio de metabolismo foi realizado com 90 aves, determinando-se a energia metabolizavel aparente, corrigida pelo balanco de nitrogenio e o coeficiente de metabolizabilidade da materia seca (CMMS) das racoes, e tambem o balanco e retencao de nitrogenio (N) e fosforo (P). As dietas nao influenciaram o desempenho, teor de cinzas na tibia e os rendimentos de carcaca, peito e coxa + sobrecoxa. Entretanto, as aves alimentadas com a racao contendo 16% de PB apresentaram maior teor de gordura abdominal. As racoes com 19% de PB apresentaram menor valor energetico e CMMS. A retencao de N e P foi maior nas aves que receberam as racoes com reduzidos teores de PB e fitase. Portanto, quando a racao de frangos de corte e suplementada com fitase e aminoacidos e possivel reduzir a PB, Pdip e Ca em ate 16; 0,262 e 0,524%, respectivamente.

Fontes e níveis de glicerina para frangos de corte no período de 8 a 21 dias de idade

umidade da cama de pintos de corte recebendo racoes com diferentes niveis e fontes de glicerina. Foram utilizados 1300 pintos de corte machos Cobb 500, num arranjo fatorial 4x3+1, com delineamento inteiramente casualizados, sendo quatro niveis de inclusao (17,5; 35,0; 52,5 e 70,0g/kg) de tres glicerinas (bruta de soja (GS), bruta mista (GM) e semipurificada (GPUR) nas dietas isonutritivas e um tratamento sem glicerina, sendo que para as fontes e niveis de glicerina foram teste de Student-Newman-Keuls e analise de regressao, respectivamente; e para o tratamento, teste de Dunnett. Utilizou-se quatro repeticoes e 25 aves por parcela. O consumo de racao foi influenciado (P<0,05) pelas fontes de glicerina, sendo a GM a fonte que promoveu menor consumo nas aves, porem, nao houve diferenca dos tratamentos em relacao ao controle. Nao houve diferenca significativa para o ganho de peso. Houve interacao dos niveis e fontes de glicerina para a conversao alimentar. Para a GS, a melhor conversao alimentar com a inclusao de 50,35g; para a GM, houve uma piora linear com o aumento da inclusao de glicerina. Houve interacao para a concentracao de glicerol serico nas aves, obtendo aumento linear nas aves que ingeriram a GS e GPUR, e reducao linear para a GM. O ganho de umidade da cama foi influenciado pelas fontes de glicerina, sendo que a mista apresentou menor umidade. As glicerinas estudadas podem ser incluidas nas racoes para pintos de corte ate 70,0g/kg, sem prejudicar o desempenho dos animais. Palavras-chave: aves, desempenho, glycerol, umidade de cama.

Efeito de diferentes relações treonina: lisina digestíveis, suplementadas ou não com glicina, sobre a atividade enzimática em pintos de corte

O experimento foi conduzido com o objetivo de avaliar o efeito da suplementacao de glicina em dietas com diferentes relacoes treonina:lisina digestiveis sobre a atividade de enzimas que metabolizam a treonina. Foram utilizados 560 pintos de corte machos, linhagem Cobb, durante o periodo de 8 a 21 dias de idade, distribuidos em delineamento inteiramente casualizado, num arranjo fatorial 3 × 2 + 1, composto de tres relacoes treonina:lisina digestiveis (55; 65 e 75%), com suplementacao ou nao de glicina, mais um tratamento adicional, contendo farinha de carne e ossos e com relacao treonina:lisina digestiveis de 65%. Utilizaram-se oito repeticoes por tratamento e 10 aves por unidade experimental alojadas em baterias metalicas. Procedeu-se a coleta total de excretas durante toda a fase experimental. Para determinacao 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 figado. As relacoes treonina:lisina influenciaram a atividade das tres enzimas no figado: a maior atividade de treonina aldolase foi para a relacao de 75%; a de treonina desidrogenase para a relacao de 65%, e a de treonina desidratase para a relacao de 55%. A suplementacao de glicina reduz a atividade de todas as enzimas avaliadas.

Efficiency of microbial phytases in diets formulated with different calcium:phosphorus ratios supplied to broilers from 35 to 42 days of age

ABSTRACT The aim of this study was to investigate the efficiency of six microbial phytases (named of A to F) supplemented in diets (1500 FTU/kg) formulated with three different calcium:available phosphorus ratios (3.5:1.0, 5.0:1.0 and 6.5:1.0). Moreover, one positive control diet without phytase that was formulated with a calcium:available phosphorus (Ca:AP) ratio of 6.5:3.0 was also considered. The utilization of dietary nutrients, as well as the bone, plasma and performance parameters of broilers from 35 to 42 days of age was evaluated. Phytase D increased the P and magnesium plasma concentrations. Broilers fed diets containing phytase B showed a lower feed intake and weight gain, while the birds fed diets containing phytase E consumed more feed, gained more weight and excreted less total P. The highest Ca retention and also the best nitrogen utilization were determined when the diet contained phytase D or E. For all phytases evaluated, an increased in the dietary Ca:AP ratio increased the tibia ash content and the Ca balance. Phytase utilization reduced the phytate P excretion, improving its utilization by the broilers. For the rearing period evaluated, it is possible to reduce the AP of the diet to 1.0 g/kg when Ca is maintained at 6.5 g/kg, and the diet is supplemented with 1500 FTU of phytase A, B, C, D or E/kg. This diet allows the maintenance of performance, optimizes the bone mineralization, and it improves the Ca, total P, phytate P and nitrogen utilization in addition to reducing the P excretion.

Energetic and nutrient metabolizability values of corn obtained with nutritional corrections for broilers

The experiment was carried out to evaluate the influence of nutritional correction on the partial diet replacement or pure-food methodology to determine the energy values (apparent metabolizable energy - AME and nitrogen-correct apparent metabolizable energy - AMEn) and coefficient of metabolizability of nutrients of maize. The method of total excreta collection was used, with 120 female Cobb 500® broilers weighing 1,339±3 g and at 28 days of age distributed in a completely randomized design with five replicates and four birds per experimental unit. The treatments were pure maize with three levels of nutritional correction (0, 50 and 100%) and a maize-replaced basal diet (400 g/kg) with two levels of correction (0 and 100%). The corrections were made in order to meet the nutritional requirements of calcium, available phosphorus and sodium yonder trace minerals, vitamins, choline, lysine, methionine + cystine, threonine and tryptophan. The AME and AMEn of maize and coefficient of metabolizability of dry matter were higher when correction at 100% was made, regardless of the methodology used (pure feed or replaced basal diet). The correction at 50% of nutrients increased the coefficient of metabolizability of crude protein in pure maize when compared with 0 or 100% of correction. The values determined with pure maize were lower than those determined with the method of partial replacement. The absence of nutritional correction underestimates the energy values and metabolizability of nutrients from maize.