Abstract This study investigated the effects of the addition of different antioxidants to broiler diets on their live performance, liver antioxidant composition and concentrations, immune response, and meat and skin color. A total of 945 three-day-old Ross 308 broiler chicks of both genders were randomly allocated to one of nine dietary treatments (n=105), with three replicates 35 chicks per pen, as follows: T1: control (commercially available corn-and soybean-based broiler diet); T2: selenium (control+0.5 mg/kg Sel-PlexTMSe yeast); T3: vitamin E (control+200 mg/kg Kavimix-E-50 a-tocopherol acetate); T4: lutein (control+100 mg/kg 5% Lutein Beads XB); T5: lycopene (control+100 mg/kg 5% Lyco Beads XB);T6: canthaxanthin (control+25 mg/kg 10% Carophyll(r)Red);T7: apo-ester (control+25 mg/kg 10% Carophyll(r)Yellow); T8: lutein+zeaxanthin (control+25 mg/kg Xamacol(r)); and T9: b-carotene (control+100 mg/kg 10% Rovimix(r)). Feed (starter, grower, developer and finisher phases) and water were provided ad libitum for 42 days. Body weights, feed intake, feed conversion values and plasma carotene concentrations were recorded weekly, and liver antioxidant concentrations were recorded at the end of the experiment. Newcastle disease (LaSota) vaccination was performed on day 22. HI titers were measured on days 14, 21, 35 and 42 to determine the effects of the antioxidants on the immune system. The addition of selenium, vitamin E, and carotenoid supplements to the commercial broiler diet significantly increased antioxidant accumulation in the liver and the plasma. All antioxidants assessed significantly improved the immune response. Selenium and vitamin E supplementation also significantly improved total carotenoid concentrations in the plasma. The carotenoids enhanced skin and meat color. None of the supplements tested influenced growth (p>0.05).

The neonatal mortality rate reflects the standard of living and quality of perinatal care. Neonatal mortality was analysed in the San Juan de Dios Hospital, Santiago, Chile, during a 15 year period from 1983 to 1997. During the study period 108,374 live infants were born, of them 1,190 have died. The neonatal mortality rate has significantly decreased from 15.3 in 1983 to 6.9 per 1000 live newborn infants in 1997. This decrease has been observed for each 500 g subgroup, mainly in babies between 1,000 and 1.499 g. Deaths occurred in 21% in the first hour and in 52% in the first day of life. Leading causes of death have been classified into major pathological subgroups, based on the suggestions of Wigglesworth et al. The most frequent causes of death were conditions associated with prematurity (45%), congenital malformations (21%), infections (17%), perinatal hypoxia (13%) and miscellaneous (4%). The overall and specific birth weight neonatal mortality rate have decreased due to several factors such as resident neonatologist since 1983, availability of single-use disposible materials available since 1990 and exogenous surfactant available in 1991 and 1994

La mortalidad neonatal (MNN) es uno de los indicadores del nivel de vida y de la calidad de la atención médica perinatal. La mortalidad neonatal se analizó en el hospital San Juan de Dios de Santiago durante 15 años, desde 1983 a 1997. Durante este período de estudio nacieron vivos 108 374 niños, de los cuales fallecieron 1 190. El objetivo de este análisis fue determinar la tasa de MNN global, de acuerdo al peso de nacimiento, sexo, edad de fallecimiento y causa principal de muerte. Para la causa principal de muerte se utilizó la clasificación de Wigglesworth, modificada. La mortalidad neonatal global disminuyó de 15,3 en 1983 a 6,9/1 000 nacidos vivos en 1997 (p < 0,001). Esta disminución ocurrió en todos los tramos de peso al nacer, especialmente entre 1 000 y 1 499 g. Predominó el sexo masculino (p < 0,001). El 21% de los RN falleció en la primera hora y el 52% en el primer día de vida. La causa principal de muerte la constituyeron las condiciones asociadas a prematurez (45%), seguidas de malformaciones congénitas (21%), infecciones (17%), hipoxia perinatal (13%) y misceláneas (4%). La MNN disminuyó debido, entre otros factores, a: inicio de la residencia neonatológica en 1983, disponibilidad de insumos desechables permanentemente desde 1990 y uso de surfactante artificial profiláctico y terapéutico en RN con enfermedad de membrana hialina y ventilación mecánica, en 1991 y 1994