Energy and ether extract digestibility of commercially available lipids fed to broilers

SUMMARY: Energy is an expensive component of diets with lipids providing a concentrated energy source to meet these needs; in addition, supplementary lipids affect milling efficiency and diet palatability. Because of the increased use of lipids as feedstocks in renewable energy production, typical fats and oils are becoming more limited and costly to the livestock industry necessitating the need to source and understand the caloric values of alternative lipids. The experiments reported herein determined the caloric value of typical and non-typical fats when supplemented to growing broilers and compared these empirical values to values predicted by commonly used equations. Thirteen sources of lipids consisting of an animal-vegetable fat blend, poultry fat, 3 soybean oils, 3 distillers corn oils, palm oil, acidulated canola-soybean oil soapstock, acidulated palm oil-soybean oil soapstock, flaxseed oil, and canola oil were evaluated. Differences in the determined nitrogen corrected apparent metabolizable energy (kcal/kg) were observed among the lipids tested (animal-vegetable fat blend, 7,671; poultry fat, 7,984; 3 soybean oils, 8,118, 7,535, and 8,767; 3 distillers corn oils, 8,205, 7,990, and 9,364; palm oil, 7,408; acidulated canola-soybean oil soapstock, 8,056;, acidulated palm oil-soybean oil soapstock, 7,685; flaxseed oil, 8,588; and canola oil, 7,854) and the use of a commonly used prediction equation did not adequately estimate the caloric value compared with the empirical values. Data presented also shows the difficulty of determining and predicting energy values of lipids when used at low inclusion levels

Exigências de treonina para frangos de corte machos nas fases de 1 a 20, 24 a 38 e 44 a 56 dias de idade Threonine requirement of male broiler chicks from 1 to 20, 24 to 38 and 44 to 56 days of age

Três experimentos foram realizados com o objetivo de determinar a exigência de treonina e a relação treonina:lisina digestível para frangos machos, Avian Farm, nas fases de 1 a 20, 24 a 38 e 44 a 56 dias de idade. Os experimentos foram conduzidos em delineamento inteiramente casualizado, com cinco níveis de treonina digestível, seis repetições e 20 aves por boxe nas fases de 1 a 20 e 24 a 38 dias de idade e 16 aves por boxe na fase de 44 a 56 dias de idade. Os níveis de treonina digestível utilizados nas diferentes fases foram: de 1 a 20 dias de idade, 0,684 a 0,870% (incremento de 0,047%); de 24 a 38 dias de idade, 0,637 a 0,807% (incremento de 0,043%); e de 44 a 56 dias de idade, 0,565 a 0,715% (incremento de 0,037%). No final de cada experimento, foram avaliadas as características de desempenho e a qualidade de carcaça. Houve efeito quadrático para consumo de ração e ganho de peso na fase de 1 a 20 dias de idade. A exigência de treonina digestível (total) na fase de 1 a 20 dias de idade foi de 0,777% (0,890% total), correspondente a uma relação treonina:lisina de 67%, de acordo com os resultados de ganho de peso e com o modelo descontínuo. Não houve efeito dos níveis de treonina sobre as características de desempenho, sugerindo que o nível de treonina digestível (total) de 0,637 (0,731% total), correspondente a uma relação de 60%, foi suficiente para atender às exigências das aves na fase de 24 a 38 dias de idade, no entanto níveis mais baixos devem ser estudados para determinação do valor exato da exigência. Observou-se efeito linear dos níveis de treonina digestível sobre o rendimento de perna na fase de 24 a 38 dias de idade. Não houve efeito dos níveis de treonina sobre as características de desempenho e rendimento de cortes nobres na fase de 44 a 56 dias de idade, sugerindo que o nível de treonina digestível (total) de 0,565% (0,650% total), correspondente a uma relação de 60%, foi suficiente para atender à exigência, mas níveis mais baixos devem ser estudados para a fase de 44 a 56 dias.<br>Three assays were carried out to determine the threonine requirement and the digestible threonine:lysine ratio of broiler males, Avian Farm, from 1 to 20, 24 to 38 and 44 to 56 days of age. A completely randomized design with five levels of threonine, six replicates and 20 birds per pen from 1 to 20 and 24 to 38, and 16 birds per pens from 44 to 56 were used in each experiment. The concentrations of digestible threonine were 0.684 to 0.870% (in increments of 0.047); 0.637 to 0.807% (in increments of 0.043); and 0.565 to 0.715 (in increments of 0.037) for 1-20, 24-38 and 44-56 days of age, respectively. A quadratic effect due to increasing digestible threonine levels were observed for feed consumption and body weight gain in the 1 to 20 day phase. Using the broken line model, the digestible (total) threonine requirement and the digestible threonine:lysine ratio were 0.777 (0.890 total) and 67%, respectively, according to the results of body weight gain. Not significant response for body weight gain and feed conversion in the second phase (24 to 38 days) showed that the lowest level of threonine met the birds requirement, but the minimum requirement should be lower. Therefore, the digestible (total) threonine requirement and ratio were .637% (.731% total) and 60%, respectively. Leg quarter yield responded linearly with the increase of the threonine level in the second phase (24 to 38). Not significant response for performance, carcass and parts yields in the third phase (44 to 56 days) indicated that the lowest level of threonine met the birds requirement, but new studies should be conducted to determine the minimum requirement. Therefore, the digestible (total) threonine requirement and ratio to maximize the performance were .565 (.650% total) and 60%, respectively