ABSTRACT
Amino acid requirements can be studied maintaining or not the ratio of the amino acids to lysine and changing or not dietary crude protein level. A third alternative was studied in this study conducted to evaluate broiler performance and weight gain of carcass parts, in response to increasing dietary digestible lysine (dig Lys) levels (0.70, 0.80, 0.90, 1.00, 1.055, 1.11, 1.165, and 1.22%). Two basal diets were formulated to contain 19.0% (diet A) and 20.5% (diet B) crude protein, and Met, Arg and Thr levels were formulated to maintain their ideal ratio to Lys. Three hundred and twenty CobbXCobb500 broilers, from 19 to 40 days of age, were used. Basal diet A was set for the 4 lowest levels of dig Lys, and diet B for the other four levels. Body weight (BW), weight gain (WG), feed intake, Lys intake, feed conversion (FC), carcass part weights and carcass, breast, leg, and thigh protein and fat were evaluated. Body weight, WG and Lys intake linearly increased with increasing dietary dig Lys, independently of basal diet CP content. A multiple regression effect was observed for FC, with the best estimated levels of dig Lys of 0.96% and 1.18% for diet A and B, respectively. Breast and carcass weight gain and breast protein and water gain showed multiple regression and split curves as a function of basal diet. The best responses were obtained with the highest crude protein level in the basal diet. Therefore, we concluded that high levels of crude protein in basal diets are recommended to study amino acid requirements for broilers.
ABSTRACT
Amino acid requirements can be studied maintaining or not the ratio of the amino acids to lysine and changing or not dietary crude protein level. A third alternative was studied in this study conducted to evaluate broiler performance and weight gain of carcass parts, in response to increasing dietary digestible lysine (dig Lys) levels (0.70, 0.80, 0.90, 1.00, 1.055, 1.11, 1.165, and 1.22%). Two basal diets were formulated to contain 19.0% (diet A) and 20.5% (diet B) crude protein, and Met, Arg and Thr levels were formulated to maintain their ideal ratio to Lys. Three hundred and twenty CobbXCobb500 broilers, from 19 to 40 days of age, were used. Basal diet A was set for the 4 lowest levels of dig Lys, and diet B for the other four levels. Body weight (BW), weight gain (WG), feed intake, Lys intake, feed conversion (FC), carcass part weights and carcass, breast, leg, and thigh protein and fat were evaluated. Body weight, WG and Lys intake linearly increased with increasing dietary dig Lys, independently of basal diet CP content. A multiple regression effect was observed for FC, with the best estimated levels of dig Lys of 0.96% and 1.18% for diet A and B, respectively. Breast and carcass weight gain and breast protein and water gain showed multiple regression and split curves as a function of basal diet. The best responses were obtained with the highest crude protein level in the basal diet. Therefore, we concluded that high levels of crude protein in basal diets are recommended to study amino acid requirements for broilers.
ABSTRACT
Amaranth is a pseudocereal that has received a lot of interest due to its nutritional, functional and agricultural characteristics, besides its potential use in the food industry. Prior to America colonization, the amaranth grain was considered a holy seed by several pre-Colombian civilizations. It represented the third staple crop for these cultures. Amaranth is among the 36 most promising crops to feed humanity and its cultivation and consumption may increase the food supply to more vulnerable populations. Its leaves (consumed as a vegetable) and its grains (consumed as a cereal) can both be used to prepare bread, cakes, cookies, salad sauces, drinks and other foods. Both the leaf and the grain present exceptional nutritious value. The amaranth grain presents a better amino acid profile as compared to other cereal grains. It is rich in lysine and sulfur amino acids. In the lipid fraction, the high levels of polyunsaturated and monounsaturated fatty acids and squalene are outstanding. The amount of dietary fiber (4% to 8%) exceeds the level observed in other cereals (around 2%). Regarding minerals, Ca, Fe, Zn, Mg and P are present in noticeable amounts. The claim that amaranth would be a functional food has resulted from studies performed with animals, which have demonstrated the grain capacity to reduce the serum cholesterol levels. It is suggested that this property would be related to synergic effects of its components: protein, dietary fiber, amino acid balance, fatty acids and squalene
El Amaranto es considerado uno pseudocereal que ha despertado la atención debido a sus características nutricionales, funcionales, agrícolas y su potencial de aplicación en la industria de alimentos. Antes de la colonización americana el grano de amaranto era considerado sagrado por diversas civilizaciones precolombinas y representaba el tercer cultivo en el consumo de esos pueblos. El amaranto integra la lista de lastreinta y seis culturas más promisorias para la humanidad y su utilización podría contribuir para mejorar la seguridad alimentar de poblaciones vulnerables. Sus hojas, consumidas como hortaliza, y los granos, como cereal, hacen parte de diversas preparaciones culinarias ta como panes, bollos, galletas, salsas para ensaladas y bebidas, entre otros. La hoja y el grano presentan excepcional valor nutritivo. El grano presenta um perfil de aminoácidos superior al de los cereal es siendo especialmente rico en lisina y aminoácidos sulfurados. La fracción lipídica se destaca por el alto contenido de ácidos grasos poliinsaturados, monoinsaturados y escualeno. El tenor de fibra dietética (4% a 8%) supera los valores observados en los cereales (2%) y en relación a los minerales se destaca la presencia de calcio, hierro, zinc, magnesio y potasio en cantidades importantes. La alegación de alimento funcional para elamaranto emana de estudios conducidos com animales, los cuales demostraron la capacidad del grano de reducir los niveles de colesterol plasmático. Se considera que esta propiedad puede estar relacionada a efectos sinérgicos de sus componentes: fibra dietética, proteína, balance de aminoácidos, ácidos grasos y escualeno
O amaranto é um pseudo cereal que tem despertado especial interesse devido às suas características nutricionais, funcionais, agrícolas e potencial de aplicação na indústria de alimentos. Antes da colonização das Américas, o grão de amaranto era considerado sagrado para diversas civilizações pré-colombianas, representando a terceira cultura consumida por estes povos. O amaranto integra a lista das 36 culturas mais promissoras para alimentar a humanidade e seu cultivo e consumo poderão aumentar a segurança alimentar de populações vulneráveis. Suas folhas, consumidas como hortaliça, e os grãos, como cereal, participam de diversas preparações culinárias, tais como pães, bolos, biscoitos, molhos de salada, bebidas, entre outros produtos. Tanto a folha quanto o grão apresentam excepcional valor nutritivo. O grão apresenta perfil de aminoácidos muito superior ao de outros cereais, sendo especialmente rico em lisina e aminoácidos sulfurados. Na fração lipídica, destaca-se o alto teor de ácidos graxos polinsaturados, monoinsaturados e o esqualeno.A fração fibra alimentar (4% a 8%) supera os valores observados nos cereais (2%). E, quanto aos minerais, destaca-se a presença de Ca, Fe, Zn, Mg e P em quantidades significativas. A alegação de alimento funcional para o amaranto advém de estudos conduzidos com animais, os quais demonstraram a capacidade do grão em reduzir os níveis de colesterol sérico. Sugere-se que esta propriedade esteja relacionada a efeitos sinérgicos de seus componentes: fibra alimentar, proteína, balanço de aminoácidos, ácidos graxos e esqualeno