Physiological roles of avian eyes in light perception and their responses to photoperiodicity

Photoperiod manipulation corrects the negative effect of low dietary crude protein levels during weeks 12 to 26 on bone quality and fertility of male Guinea fowl (Numida meleagris)

Improving the reproductive performance of guinea fowl (Numida meleagris) based on the management of environmental factors is important for developing meleagriculture. Thus, the present study was conducted to evaluate the effect of dietary crude protein levels and photoperiod during the 12th to 26th wk of age on growth performance, calcium and phosphorus mobilization, and fertility of local Pearl Gray male guinea fowl. In total, 120 twelve-week-old male guinea fowl were divided into 3 groups with 8 replicates each and 5 birds per replicate using a completely random design. The experimental groups included: a group fed a diet containing 15% crude protein and subjected to 16 h of light and 8 h of darkness (16LL), a group fed a diet containing 19% crude protein and subjected to 16 h of light and 8 h of darkness (16HL), and a group fed a diet containing 15% crude protein and subjected to 18 h of light and 6 h of darkness (18LL) during the 12th to 26th wk of age. The results showed that guinea fowl in the 16HL treatment had a significantly (P = 0.003) lower feed conversion ratio than those in the 16LL and 18LL groups. Calcium and phosphorus levels in the tibia and femur were significantly higher (P < 0.05) in guinea fowl of the 16HL and 18LL groups than in that of the 16LL group. Birds in the 16HL and 18LL treatments had significantly higher peripheral testosterone levels (P < 0.00001) than those in the 16LL treatment. The 16HL and 18LL treatments had significantly higher (P < 0.05) sperm volume, sperm concentration and motility, and fertility rate than the 16LL group. Therefore, a decrease in crude protein level from 19 to 15% in the diet of male guinea fowl between the 12th and 26th wk of age negatively affects the growth performance and fertility of these birds, but this is corrected by an increase in the photoperiod before sexual maturity.

Does light color during brooding and rearing impact broiler productivity?

Light color during brooding and rearing may impact broiler production; however, literature results are inconsistent. To address this, the effects of 3 wavelength spectra on broiler performance in 2 sex and 2 genotypes (Ross YPMx708 and EPMx708) were studied. Broilers were raised (d 0–35) under wavelength programs provided by LED light bulbs (blue (455 nm), green (510 nm) or white) under similar intensities (clux). Two trials were conducted (total number of birds =  14,256; 6 room replications per lighting treatment; 18 replicate pens per light × sex × genotype). Data were analyzed as a 3 × 2 × 2 (wavelength × sex × genotype) factorial design, with trial as a random variable block and wavelength nested within rooms (Proc Mixed, SAS 9.4). Birds raised under white light were heavier than under blue or green light at d7 (P = 0.004), and green at d14 (P = 0.03). Feed intake, gain-to-feed efficiency and flock uniformity (d15, 28) did not differ. Mortality only differed at wk 5, when broilers raised under white light had higher mortality than those raised under blue (P = 0.03). YPM-708 were heavier at 21 d (P = 0.007), 28 d (P = 0.001), and 35 d (P < 0.0001), had a better total feed conversion rate (P < 0.0001), higher mortality for wk 1 (P = 0.001), lower mortality during the last wk (P = 0.02) and better uniformity at 28 d (P = 0.01) than EPM-708 broilers. Males were heavier at all measured ages except d0 (d7-P = 0.03, other weeks P < 0.0001), had better total feed conversion (P < 0.0001), increased weekly mortality except for wk 1 (wk2-P = 0.04, wk3-P = 0.002, wk4, 5, and total-P = 0.0001) and were less uniform (P = 0.0002) than females. YPM-708 and EPM-708 males had higher total feed intake (P < 0.0001), and males raised under white light had higher mortality than females raised under white or blue light (P = 0.01). To conclude, the use of specific light colors (blue and green) had only minor impacts on broiler production when light intensity was equalized and balanced for bird spectral sensitivity, and its use to improve productivity does not appear to be advantageous for broilers in a commercial setting.

The Effects of Feed Color on Broiler Performance between Day 1 and 21

Two trials were conducted to determine feed color effects on broiler performance. A completely randomized design was used. Trial 1 included four treatments: control (complete broiler starter diet), red, green, and blue; and Trial 2 included four treatments: control, orange, yellow, and purple. Each trial had 4 treatments with 4 replicates (60 birds/treatment) fed to 240 male Cobb 500 broilers during a 21 d grow out. Data were analyzed using the GLM procedure. In Trial 1, there were no treatment effects on average body weight, body weight gain, and feed consumption (p > 0.05). Adjusted feed conversion for control (1.23) was less than red (1.27; p = 0.001) and green (1.26; p = 0.009), with blue (1.25; p = 0.056) tending to be different during the experimental period. In Trial 2, there were no treatment effects on average body weight, feed consumption, and adjusted feed conversion during this study (p > 0.05). Body weight gain between d 1 to 14 for purple (490.78 g/bird) was more than orange (467 g/bird; p = 0.013) and yellow (461 g/bird; p= 0.004), with control (474 g/bird; p = 0.052) tending to be different. Results indicate that these feed colors had some, albeit limited, influence on broiler performance parameters.

Impact of lighting color and duration on productive performance and Newcastle disease vaccination efficiency in broiler chickens

Background and Aim

Manipulating lighting colors and regimens is considered an effective mean for improving broiler productivity. The influence of red, blue, and white light-emitting diode (LED) was investigated using three different regimens of lighting and darkness; continuous 23 h light (L):1 h dark (D), continuous 18 h L:6 h D, and intermittent 16 h L:8 h D hours on the performance, carcass weight (CW), feed and water intake (WI), serum glucose (GLUCO), triglycerides (TG), and cholesterol (TC), intestinal bacterial load, growth and metabolic hormones, and efficiency of Newcastle disease (ND) vaccine.

Materials and Methods

A total of 252 1-day-old Ross broilers on deep litter were divided into nine groups. The 1^st, 4^th, and 7^th groups were exposed to continuous 23L:1D, the 2^nd, 5^th, and 8^th groups were exposed to continuous 18L:6D, and the 3^rd, 6^th, and 9^th groups were exposed to intermittent 16L:8D (4L:2D, 4 times) lighting regimen using red, blue, and white LED lights, respectively. A total of 1350 samples (225 sera, 225 swabs, and 900 organ samples) were collected.

Results

Blue LED group revealed a highly significant increase (p<0.01) in live body weight, body weight gain, performance index, CW, spleen, heart, and liver weights, and anti-ND antibody titer, as well as a highly significant decline (p<0.01) of feed intake, WI, GLUCO, TG, TC, growth hormone, insulin, tri-iodothyronine (T3), tetra-iodothyronine (T4), total bacterial count (TBC), and total Enterobacteriaceae count compared to red and white LED lights in all tested lighting regimens. Continuous 23L:1D and 18L:6D regimens were significantly (p<0.01) superior to intermittent 16L:8D in their influence on the performance, CW, biochemistry, hormonal profile, and bacterial load.

Conclusion

The blue LED light associated with continuous 18L:6D or 23L:1D h regimen is highly recommended in broiler houses for their enhancing the productive performance, growth, and immunity.