E-learning of mathematics using problem-based learning by designing a new software program and studying its impact on the mathematical performance of secondary high school students

Abstract

Introduction: This experiment subjected to investigate
on growth performance, the immune system and internal organs of the broiler chicks. Materials & Methods: A total of 300 one day-old male broiler chicks (Ross-308) were
weight. Each group
20 birds per pen.
conditions were similar for all treatments throughout the experimental period except lighting programs which from 8 to the 42 day were provided as follow: 1) 23 h light (L): 1 h dark (23L:1D), 2) 16 h L: 8 h D (18L:6D) and 3) 12 h L: 12 h D (12L:12D). At 35day-old, 0.2 mL of SRBC was injected intravenously into the chicks and at the 42 day-old, 4 chicks were randomly selected from each replicate. Anti-SRBC antibody titers were determined using a heamagglutination technique. Then Chicks were slaughtered and their bursa of fabricus, spleens, liver, heart, crops, gizzard and jejunum weighted and also length of jejunum were measured. Result: The Anti-SRBC titer was the lowest with 23L:1D and the highest in the birds of 12L:12D treatments respectively (P<0.01). The lowest weights of internal organelles were in 23L:1D and the highest in 12L:12D treatments. The weight gains and feed conversion ratio between the treatments was significantly different in all the periods and improved with more dark hours (P<0.05). Conclusion: It is concluded that lighting program with long darkness improved growth and immune indices in broilers.