Effect of Light Intensity and Photoperiod on Live Performance, Heterophil-to-Lymphocyte Ratio, and Processing Yields of Broilers

Abstract

This study investigated effects of light intensity and photoperiod on live and processing performance and physiological stress of broilers. One hundred broilers were housed in each of 12 rooms, provided 23L:1D with 3 footcandles (FC) of intensity to 8 d, and then subjected to the following treatments in a 2 x 2 factorial arrangement: either 1 FC (1FC) or 0.1 FC (0.1FC) from 8 to 49 d and either 23L:1D from 8 to 49 d (23L) or 18L:6D from 8 to 43 d followed by 23L:1D from 43 to 49 d (18L). At 40 d, blood samples were drawn and heterophil:lymphocyte ratios determined. At 49 d, 16 birds from each room were processed to determine weights and yields. There were interaction effects on BW from 29 to 49 d. At 29 d, BW was reduced by either 18L or 0.1FC treatments. At 43 d, BW was greatest in 1FC-23L, reduced in 1FC-18L and 0.1FC-23L, and intermediate in the 0.1FC-18L treatment. At 49 d, BW of 1FC-23L and 0.1FC-18L were similar and greater than those of 1FC-18L and 0.1FC-23L treatments. Feed consumption was reduced by 18L treatment from 15 to 29 d and the 0.1FC treatment at 15 d. Feed conversion and mortality were not affected by treatments. The 0.1FC treatment decreased uniformity at 15 d. Heterophil:lymphocyte ratios averaged about 0.45 and were not affected by treatments. Carcass yield and tender weight were reduced by the 0.1FC treatment, whereas whole breast yield was reduced by the 18L treatment. There were interaction effects on whole breast weight and fillet weight and yield, which were reduced by either the 18L or 0.1FC treatments. These results indicate that although the combination of 18L:6D and 0.1FC may result in broiler live performance comparable to that achieved with 23L:1D and 1FC, and no combination of the photoperiods and intensities tested caused physiological stress, breast meat is generally reduced by either 18L:6D or 0.1FC.

Etlik piliçlerde Fotoperiyot Uzunluğu ve Işık Şiddetinin Performans, Karkas Özellikleri ve Heterofil/Lenfosit Oranı Üzerine Etkileri

“…On the other hand, photoperiod has no effect on H/L ratio. Similar results were reported in some studies carried out in broilers in which the effect of photoperiod on H/L ratio were statistically nonsignificant [11] . However, Coban et al [21] had recorded lower H/L ratio in 16L:8D photoperiod group than counterparts subjected to continuous lighting (P<0.001).…”

“…Similarly, as reported in some studies that the extension of the light period from 18 h to 23 h [11] and from 14 h to 23 h [22] resulted in heavier whole breast. Lewis et al [24] also indicated that continuous lighting increased the weight of breast meat.…”

“…But, at the market age (d 56), photoperiod treatment has no significant effects on BW and FC. Similarly, in other studies the effect of photoperiod on FCR was found to be statistically not significant [4,11,13,17,20] . There was photoperiod length x light intensity interaction on BW of broilers at different periods of growth, except for 36 d. As Downs et al [4] , Lien et al [11] , Çoban et al [21] reported that the photoperiod length has no statistically significant effects on mortality.…”

“…Similarly, Downs et al [4] , Lien et al [11] , Charles et al [27] reported that there was no effect of light intensity on FC. Kristensen et al [10] also reported no effect of intensities varying from 53.80 lux to 64.56 lux as in contrast to 107.6 lux to 124.82 lux was observed on FC.…”

“…The effect of light intensity (ranging from 1 to 150 lx) on body weight (BW), FC, feed conversion ratio (FCR) and mortality in broiler chickens was reported as statistically nonsignificant by some studies [10][11][12] . Processed fillet weights were reported to be higher in 1.08 lux light intensity (dim light) than those kept in 161.4 lux light intensity (bright light) [13] .…”