Abstract

A total of 357 Isa Brown layers were used in this study in order to assess the effects of lighting length on laying performance and on some egg characteristics in a family farm of Antananarivo suburb, Madagascar. The birds, in their egg producing phase (37 week old), were distributed at random into one of 3 lots, each allocated to one of 3 lighting treatments: 12 hour natural daylight, used as control; 14 hour lighting length (natural daylight + artificial light) and 16 hour lighting length (natural + artificial light). The artificial lighting was supplied by 60 Watt incandescent lamps placed within the treated lots. Eggs, numbering 840, were taken at random in order to assess their physical and chemical characteristics. Thus, lighting length affects significantly layer weight and production performance (p<0.05). Layer weights tend to be lower with increasing lighting, but egg production increase with lighting length. Lighting length has no effect neither on egg weight nor on egg volume, but it affects significantly the shell index (p=0.0018) and egg internal qualities (p<0.05), except for yellow pH.

Keywords: Poultry; Layers; Lighting length; Performance; Egg characteristics; Madagascar