NUTRITION
No TL;DR found
Abstract
The role of darkness in the management of broiler production has yet to be determined, but considerable evidence suggests that the use of continuous or near-continuous light should not be recommended (Classen, 1988; Classen and Riddell, 1989; Al-Homidan and Petchey, 2000) . Intermittent lighting programmes have also been shown to improve bird health while maintaining equal or superior growth and feed conversion ratio to birds given continuous light (Zakaria, 1985; Al-Homidan and Petchey, 2000) . The following studies were conducted to determine the effect of light regime litter type and sex on broiler performance. This experiment utilised a total of 380 Hybro broiler chickens grown over a 49-d period. A 4×3×2×2 randomized block design was used. Chicks were wing-banded, weighed individually and allocated randomly into the treatments with 15 chicks/replicate. Three light regimes were used (23L : 1D) , (5L : 1D) and (3L : 1D) . Two bedding materials were used, wood shavings and shredded paper. Individual body weight was recorded at hatch and thereafter at weekly intervals up to 7 weeks. The feed offered to each pen was recorded daily. At the end of each week, feed residues were weighed. Feed consumption was therefore recorded on a weekly basis and then calculated as daily feed consumed per d over the various experimental periods. The feed conversion ratio (g feed/g gain) was calculated for each experimental period and over the trial period. Any dead birds were removed daily and weighed. Their feed consumption was estimated and deducted from the total feed given to that pen during that week. All chicks were given a commercial starter diet (containing 220 g/kg crude protein and 13·2 MJ/kg DM metabolisable energy) during the period from hatch to 4 weeks and then switched to a finisher diet (containing 200 g/kg CP and 13·4 M/kg DM) during the rest of the experimental period. Feed and water were available ad libitum. The light regime had an effect (P<0·01) on body weight and daily weight gain at 7 weeks of age. Birds reared under intermittent light (3L : 1D) had a greater mean body weight and daily weight gain then those under near-continuous light (23L : 1D) or intermittent light (5L : 1D) (Table) . Higher body weight with intermittent light has also been reported by Cain (1973) who found that the body weights of pullets raised under 23L : 1D were significantly less (1562 g) than those under 1L : 1D (1621 g) , 2L: 1D (1634 g) and 3L : 1D (1603 g) . Food consumption and conversion (Table) were affected by light regimes at 7 weeks of age. Differences in body weight, daily weight gain and food consumption due to light regimes have been reported previously (Al-Homidan and Petchey, 2000) . There were significant differences due to the type of litter on broiler performance at 7 weeks of age (Table) . Males had higher (P<0·01) body weight and daily weight gain than females at 7 weeks of age. Growth performance and feed conversion