The Use of Intermittent Lighting in Broiler Raising.

The purpose of the present experiments was to compare the effects of the intermittent lighting schedule (IL) consisting of repeated cycles of 1 h light (L):3 h darkness (D) with a nearly continuous lighting schedule 23L:1D (CL) on the performance of floor-reared male and female broiler chickens. In addition, N balance trials were performed on caged broilers in order to assess their efficiency of dietary N retention. Changing from CL to IL at Day 7 was followed by a temporary reduction in feed intake and BW gain. However, IL males exhibited compensatory growth during the finisher period in such a way that at Day 41 (market age), a similar BW as that of their CL counterparts was attained. In contrast, IL females did not completely attain a BW equal to that of CL females by 41 d of age. Imposing IL reduced feed intake and improved feed conversion. Abdominal fat pad contents of broilers reared under IL were significantly smaller than those of CL broilers. From the N balance trials, it can be inferred that broilers reared under IL have an improved efficiency of dietary N retention, especially during the period of increased growth velocity. Imposing IL at Day 7 is associated with a temporary reduction in BW gain, followed by complete growth compensation of males by Day 41. Female broilers did not restore BW by this age. As a consequence of the altered growth trajectory, the manifestation of the fat growth wave is shifted to an older age together with an enhanced efficiency of N retention.