Renata Ribeiro Alvarenga

Energy values and chemical composition of spirulina (Spirulina platensis) evaluated with broilers

ABSTRACT - The objective of this study was to determine the chemical and energy composition of spirulina ( Spirulinaplatensis ), the nutrient metabolizability coefficients, and the values of apparent metabolizable energy (AME) and the apparentmetabolizable energy corrected for nitrogen balance (AMEn) in broilers. A digestibility trial was carried out by using totalexcreta collection method, with 90 Cobb 500 lineage chicks, with initial weight of 256 ± 5 g at 11 days of age. Birds were allottedin metabolic cages for 10 days, distributed in a completely randomized design, with three treatments and six repetitions withfive birds each. Diets consisted on a reference-ration based on corn and soybean meal and two test diets, one containing spirulina(30%) and the other one with soybean meal (30%). Spiruline was superior to soybean meal for contents of dry matter (DM),gross energy (9.60%), crude protein (26.56%), ether extract (54.45%), mineral matter (42.77%), calcium (100%) and totalphosphorus (130.77%) and also for most amino acids, except lysine, glutamate, histidine and proline. Nevertheless, spirulinepresented lower values of gross fiber (83.95%), acid detergent fiber (85.12%) and neutral detergent fiber (6.15). The AMEand AMEn values (kcal/kg of DM) were, respectively, 2,906 and 2,502 for the spirulina and 2,646 and 2,340 for the soybeanmeal and AMEn of spirulina was 6.92% higher than soybean meal.Key Words: non-conventional food, nutritional value, total collection

The energy value of biodiesel glycerine products fed to broilers at different ages.

The objective of this study was to determine the apparent metabolisable energy corrected for nitrogen balance (AMEn) of some products containing glycerine from soybean oil (GOIL), a mixture of frying oil and lard (GMIX) and a semi-purified process (GSP) in broilers of different ages (10, 20, 30 and 40 days post-hatching), using two methodologies. In trial 1, the basal diets were replaced with 100 g/kg of each studied glycerine product and the diets were supplied ad libitum. Three hundred broilers were used in five replicates, with five, four, three and three animals per cage in each age group, respectively. The AMEn was calculated for each experimental unit. In trial 2, dietary treatments included the addition of glycerine at 0, 40, 80 or 120 g/kg for each crude glycerine product, with 900 broilers in six replicates, using the same number of animals per cage as described in trial 1. Depending on the experimental unit, the feeding was restricted in 88%, 92%, 96% and 100% of estimated intake according to the Cobb guide. The AMEn was determined using linear regression between the feed intake and the AMEn of each diet. In both trials, the total excreta collection method was used. Because of the chemical composition, GMIX was not considered crude glycerine. The mean AMEn values of the products were 20.55 MJ/kg, 15.80 MJ/kg and 15.05 MJ/kg for GMIX, GSP and GOIL, respectively. There was a linear decrease (p < 0.01) in the AMEn values with the increasing age of the broilers. Numerically, it was observed that the AMEn values decreased until 28-30 day post-hatching and then remained constant until the finishing phase. It is concluded that products containing glycerine can be used as an energy source for broilers, but that AMEn values can vary according to age. Younger broilers have a higher capacity of energy utilisation from these feedstuffs.

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.

Nitrogen, calcium and phosphorus balance of broilers fed diets with phytase and crystalline amino acids

Objetivou-se, com este trabalho, avaliar o efeito de racoes com reduzidos teores de proteina bruta (PB) e fosforo disponivel (Pd), suplementadas com fitase e aminoacidos, para frangos de corte na fase de crescimento (14 a 21 dias) e terminacao (35 a 42 dias de idade) sobre o balanco de nitrogenio, potassio e fosforo. Foram utilizados 90 pintos Cobb, distribuidos em um delineamento inteiramente casualizado com tres tratamentos e seis repeticoes, com cinco e tres aves por unidade experimental nas fases inicial e de crescimento, respectivamente. As racoes foram formuladas para conterem niveis reduzidos de PB e Pd (19 e 17% de PB na fase de crescimento, com 0,34% de Pd e 18 e 16% de PB na fase de terminacao, com 0,30% de Pd) e suplementadas com aminoacidos e 500 FTU de fitase/kg de racao Essas racoes foram, entao, que foram comparadas a uma racao controle (21% de PB e 0,46% de Pd para fase de crescimento e 19% de PB e 0,40% de Pd para fase de terminacao). A reducao da PB em quatro unidades percentuais reduziu a excrecao, e aumentou a retencao de nitrogenio, mostrando que a fitase nao interferiu no balanco de nitrogenio ao serem incluidos aminoacidos cristalinos nas racoes. A excrecao de potassio diminuiu em dietas com PB reduzida, mas esta reducao em excesso diminuiu a retencao deste elemento, exceto na fase de retirada. Conclui-se que racoes contendo niveis reduzidos de PB, calcio e fosforo, suplementadas com fitase e aminoacidos, sao eficientes em diminuir o poder poluente das excretas de frangos de corte.

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.

Energy and protein levels in diets containing phytase for broilers from 22 to 42 days of age: performance and nutrient excretion

This study was conducted in order to evaluate the influence of different levels of metabolizable energy and crude protein in diets formulated according to the ideal protein concept with phytase supplementation on performance and nutrient excretion of broilers from 22 to 42 days age. It was used 1,500 Coob lineage broilers at 22 days of age and with initial weight of 833 ± 7g, distributed in completely randomized design in a 3 × 3 + 1 factorial scheme composed of three levels of correct apparent metabolizable energy (2,950; 3,100 and 3,250 kcal/kg), three levels of crude protein (14, 16 and 18%) and a control treatment, totaling ten treatments with six repetitions of 25 birds each. All diets, with the exception of the control, were supplemented with phytase. For determination of excretion of pollutants, it was used 180 broilers from the same lineage at 35 days of age,placed in metabolic cages, with ten treatments each one with six repetitions and three birds per experimental unit. The protein and energy levels in diets containing phytase influenced feed intake, weight gain, feed conversion and excretion of nitrogen, phosphorus, calcium, potassium, copper and zinc by the birds. The corrected apparent metabolizable energy level in the diets for broilers in the studied period must be increased up to 3,250 kcal/kg of metabolizable energy and the levels of crude protein, calcium and phosphorus must be reduced down to 18, 0.70 and 0.31%, respectively, provided that supplemented with amino acids and phytase to improve the performance and to reduce excretion of pollutants by birds.

Níveis de fósforo disponível e cálcio em rações suplementadas com fitase para frangos de corte nas fases de crescimento e final

Calcium and available phosphorus (aP) levels in diets with phytase for Cobb broilers in the growing (22 to 35 days) and finishing phases (36 to 42 days of age) were evaluated. A 3 × 4 + 1 factorial scheme, with three aP levels (0.36, 0.31, 0.26% in the growing phase and 0.33, 0.28, 0.23% in the finishing phase), four calcium levels (0.82, 0.72, 0.62, 0.52% in the growing phase and 0.76, 0.66, 0.56, 0.46% in the finishing phase), and one level of supplementation of phytase (500 ftu/kg) was used. Control diets were not supplemented with phytase and they contained, respectively, the following levels of aP and calcium: 0.41 and 0.82% (growing phase) and 0.38 and 0.76 (finishing phase). In the performance assays, at 35 and 42 days of age, feed intake, weight gain, feed conversion and the ash content in the tibia were evaluated. In the metabolic assays, the energy values of diets (AMEn) and dry matter digestibility coefficients (DMDC) were determined. In the growing phase, the reduction of the calcium and aP to 0.52 and 0.26%, respectively, did not compromise performance, bone ash, AMEn or MCDM. In the finishing phase, the reduction of the calcium and aP to 0.56 and 0.28%, respectively, did not compromise performance, AMEn or MCDM; in addition to improving bone ash. The levels of calcium and aP of diet can be reduced to 0.52 and 0.26% in the growing phase, and to 0.56 and 0.28% in the finishing phase, provided that this reduction is combined with supplementation of fitase at 500 ftu/kg of the diet.

Effect of ractopamine on the chemical and physical characteristics of pacu(Piaractus mesopotamicus) steaks

The objective was to evaluate the use of ractopamine (RAC) in the diet for pacu (Piaractus mesopotaminus) in the finishing phase on some quality parameters of the fillets. Thirty-five animals weighing 0.868±0.168kg were distributed in a completely randomised design with five treatments (0.0 - control; 11.25, 22.50, 33.75 and 45 ppm of RAC) and seven replicates with two fillets obtained from the same animal. The diets were isocaloric and isoprotein and experimental time was 90 days. RAC did not affect (P>0.05) the initial pH or ph after 24 hours of the fillets. Compared to the control, RAC increased (P<0.05) the moisture content of the fillets in natura and lipid oxidation of samples stored for 12 days in the refrigerator or freezer for 60 days. The RAC in 11.25 ppm reduced (P<0.05) the lipid content, while 45 ppm reduced (P<0.05) the crude protein in the fillets. Considering only RAC, there was a linear increase (P<0.05) in the lipid content (P<0.05) and a linear reduction in crude protein and weight loss after cooking the fillets. There was a quadratic effect (P<0.05) on the ash content, weight loss and lipid oxidation in fillets stored in the refrigerator or freezer. A RAC dose of 33.75 ppm resulted in a lower lipid oxidation index. In conclusion, ractopamine at 11.25 ppm is effective for reducing the fat content in fillets of pacu, although it increases the formation of peroxides in samples kept in the freezer for longer than 60 days. At 33.75 ppm, ractopamine is effective in reducing the effect of oxidation during storage in the refrigerator or freezer.

Equações de predição de valores energéticos de alimentos obtidas utilizando meta-análise e componentes principais

The purpose of this study was to develop a meta-analysis study by using the principal components analysis to obtain homogeneous groups of experimental results. In the process of the meta-analysis, it was considered data from 293 experiments carried out in Brazil. Prediction equations were obtained to estimate the nitrogen-corrected apparent metabolizable energy (AMEn) of poultry feedstuffs. Data from metabolic trials were used to validate the prediction equations obtained, which were similar than other available equations in the literature. One of the problems in meta-analysis is the determination of the homogeneous groups of experiments and, this problem was eliminated by using principal components, since there was no need to establish variables or factors to be considered in this classification.

Carcass characteristics of broilers at 42 days receiving diets with phytase in different energy and crude protein levels

Objetivou-se, com este trabalho, estudar as caracteristicas de carcaca e qualidade da carne do peito depois da inclusao de fitase em dietas para frangos de corte, com diferentes niveis de energia metabolizavel aparente corrigida para nitrogenio (EMAn) e proteina bruta (PB) reduzida, suplementadas com aminoacidos essenciais seguindo o conceito de proteina ideal. Foram utilizados 1.500 frangos machos Cobb dos 22 aos 42 dias de idade com peso inicial de 833 ± 7 g e final de 2741 ± 48 g distribuidos em delineamento inteiramente casualizado em esquema fatorial 3x3+1 (tres niveis de EMAn - 2950, 3100 e 3250 kcal/kg - e tres de PB - 14, 16 e 18% - e um tratamento adicional - controle, sem fitase, com 3100 kcal/kg EMAn, 19,2% de PB e 0,4% de fosforo disponivel) em seis repeticoes com 25 aves cada. Ao final do experimento, duas aves de cada parcela foram sacrificadas para a mensuracao do rendimento de carcaca e de cortes e determinacao da composicao quimica da carne do peito. Os niveis de energia e proteina em racoes com fitase influenciaram (P<0,05) os rendimentos de carcaca, peito e gordura abdominal a porcentagem de umidade, proteina e lipidios no musculo pectoralis major das aves, sendo os niveis de 3100 kcal EMAn/kg e 18% de PB os que proporcionaram maiores rendimentos de carcaca e de peito e menor deposicao de gordura abdominal, mas em maior teor de lipidios na carne do peito. Conclui-se que a manipulacao da energia em racoes com reduzido teor de proteina e suplementadas com aminoacidos e fitase influencia o rendimento de cortes e a qualidade da carne do peito de frangos aos 42 dias.