Broiler Chicken’S Growth Rate In Three Different Nocturnal Lighting Regimes

An experiment of 35 days’ duration was designed using Completely Randomized Design to study broiler chicken growth rate in three different nocturnal lighting regimes, comprising, continuous darkness (0L: 12D), light (12:0D) and extended light (6L; 6D). The study was carried out at the Teaching and Research Farm of the Rivers State University of Science and Technology, Port Harcourt- Nigeria. A total of ninety unsexed broiler chickens were randomly distributed into the three lighting treatments at the end of three weeks of age. Each treatment replicated twice with 15 chickens per replicate. The broiler chickens were brooded together for 3 weeks on deep litter in an open-sided brooding house. Three 200 watts incandescent bulbs were used to provide a brooding temperature of 34-39°C. Black polythene sheets were used in covering the brooding pens to conserve heat and to maintain a uniform temperature. There was no light restriction during the brooding period. At the end of the third week, the birds were randomly distributed into three different lighting treatments of two replicates each with 15 birds per replicate. The three different lighting regimes were administered using a fluorescent tube between the hours of 6.00pm and 6.00am as follows: continuous light (12:0D), extended light (6L: 6D) and continuous darkness (0L: 12D). Black polythene materials were used to prevent light penetration from adjoining treatments during the night. Artificial light was provided by a 40 watt 'day light' fluorescent tube in each of the treatments. The parameters measured included body weight, body weight gain, daily feed consumption and feed conversion efficiency. The results obtained showed that there was no significant differences (P>0.05) in the weekly body weight and body weight gain in all the treatments. Also, feed conversion efficiency was not significantly different (P>5.0) in all the treatments. It was, therefore, concluded that since varying photoperiod has no significant effect on broiler growth rate, it will be wasteful for broiler farmers to incur additional cost of providing and /or extending the duration of light under similar geographical zones of this experiment. Therefore, artificial light is not recommended for a profitable broiler production