@article{alfaro-wisaquillo_oviedo-rondon_cordova-noboa_v. caldas_quintana-ospina_ospina-rojas_san martin_2021, title={Effects of amino acid levels during rearing on Cobb 500 slow-feathering broiler breeders: 1. Growth and development}, volume={100}, ISSN={["1525-3171"]}, DOI={10.1016/j.psj.2021.101327}, abstractNote={Adequate pullet nutrition is essential to reach BW and suitable body composition for reproduction. An experiment was conducted to determine the effects of 4 dietary amino acid (AA) levels on BW, flock uniformity, body conformation, organ, leg, and feathering development of broiler breeder pullets during the rearing phase from 5 to 24 wk. A total of 1,360 Cobb-500 slow-feathering (SF) pullets were randomly placed in 16-floor pens with 85 females per pen. Diets with corn, soybean meal, and wheat-midds were formulated without protein restriction maintaining minimum ratios between essential AA and Lys on a digestible (dig) ideal basis. Treatments consisted of 4 dietary AA levels with 80% (low-AA), 90% (moderate-AA), 100% (standard-AA), and 110% (high-AA) of the Cobb-Vantress recommendations guided by dig Lys using balanced protein. Up to 4 wk, all pullets were fed a common starter crumble diet. Grower and developer mash diets were fed to pullets from 5 to 15 wk and from 16 to 24 wk, respectively. Pullets fed standard-AA and high-AA diets were heavier (P < 0.001) than those fed low-AA diets at 10, 15, and 20 wk of age. High-AA diets resulted in better (P = 0.040) flock uniformity at 10 wk. Pullets fed a high-AA diet had the highest (P = 0.041) relative breast weight at 20 wk of age and the lowest (P = 0.044) deposits of abdominal fat at 15 wk of age. Fleshing increased (P < 0.05) as AA content rise in the diet, while the relative shank length (P < 0.001) and the number of wing juvenile feathers (P = 0.004) decreased. Pullets fed the lowest dietary AA level had the longest (P = 0.007) small intestine relative to BW at 10 wk of age, but a smaller (P = 0.001) liver than those fed moderate and standard-AA diets at 20 wk of age. Dietary AA levels have important effects on pullet BW, fleshing, and organ development during rearing with potential reproductive performance impacts.}, number={9}, journal={POULTRY SCIENCE}, author={Alfaro-Wisaquillo, Maria Camila and Oviedo-Rondon, Edgar O. and Cordova-Noboa, Hernan A. and V. Caldas, Justina and Quintana-Ospina, Gustavo A. and Ospina-Rojas, Ivan C. and San Martin, Viviana}, year={2021}, month={Sep} }
 @article{oviedo-rondon_matta_ortiz_alfaro-wisaquillo_cordova-noboa_chico_hoyos_quintana-ospina_caldas_buitrago_et al._2021, title={Effects of amino acid levels during rearing on Cobb 500 slow-feathering broiler breeders: 2. Reproductive performance}, volume={100}, ISSN={["1525-3171"]}, DOI={10.1016/j.psj.2021.101398}, abstractNote={Crude protein and amino acid (AA) content in rearing diets affect body composition and reproductive performance. This study evaluated the effects of 4 dietary AA levels during rearing on BW, egg production and composition, fertility, hatchability, and embryo mortality up to 65 wk of age on Cobb 500 slow-feathering (SF) broiler breeders. The treatments consisted in 80% (low-AA), 90% (moderate-AA), 100% (standard-AA), and 110% (high-AA) of the AA recommendations for Cobb 500 SF pullets from 5 to 24 wk. AA was guided by an ideal protein profile based on digestible Lys. A total of 1,360 pullets and 288 Cobb MV cockerels were randomly placed in 16 pullets and 16 cockerel floor-pens. At 22 wk, 1,040 females and 112 males were transferred into 16-floor pens in a laying house. BW increased linearly (P < 0.01) as AA augmented at 25, 36, and 40 wk. No effects (P > 0.05) at the onset of lay were observed. Moderate-AA and standard-AA resulted in the best hen-housed egg production (HHEP) at 65 wk with 174.3 and 176.5 eggs, respectively. The optimum level of AA for HHEP at 65 wk was estimated (P < 0.001) in 96.7% and 94.7% by the quadratic and broken line models, respectively. Overall, the lightest egg weight (P = 0.022) was obtained with 89%AA during rearing, and the heaviest eggs (P < 0.001) were found at 54 wk. Response surface regression indicated linear effects on albumen and yolk percentages (P < 0.01) increasing and decreasing, respectively, as AA levels augmented; consequently, AA had a negative linear effect on Y:A ratio (P = 0.004) with quadratic effects (P < 0.01) of age (R2 = 0.92). No statistical effect of treatments was observed in fertility (P > 0.05), but AA had a quadratic effect (P = 0.046) on hatchability up to 50 wk of age with 97% as optimum, and decreased linearly (P = 0.004) from 51 to 65 wk. A few effects of treatments (P < 0.05) on embryo mortality were observed. In conclusion, AA levels during rearing affect broiler breeder reproductive performance.}, number={10}, journal={POULTRY SCIENCE}, author={Oviedo-Rondon, Edgar O. and Matta, Yilmar A. and Ortiz, Andres and Alfaro-Wisaquillo, Maria Camila and Cordova-Noboa, Hernan A. and Chico, Miguel and Hoyos, Juan S. and Quintana-Ospina, Gustavo A. and Caldas, Justina V and Buitrago, Daniela and et al.}, year={2021}, month={Oct} }