Introduction: Modern egg production sometimes imposes stressful breeding conditions for animals. Sensorial pleasure allows the release some neuro-hormones like dopamine or endorphins which have anti-stress properties (ESCH, 2004). Birds were traditionally thought to have a very poor sense of smell, but since 1999 confirmed in 2004, the chicken genome sequence has revealed a number of olfactive receptor genes comparable to humans (STEIGER, 2008). The idea behind sensory stimulation by a sensory feed additive is to take advantage of the important role of olfaction to improve well-being and reduce the impact of stress reaction by creating a positive sensory experience.
Materials and methods: The effect of a sensory feed additive based on both specific and purified plant extracts (VéO®Premium, Laboratoires PHODE - 250g / Mt of complete feed), was measured on 1080 Bovans white females grown from 14 days of age to 25 weeks including 10 weeks of laying production at IIIA experimental station. They were randomly distributed into 30 flocks of 36 animals each. Live body weight (LBW, n=2x200), Feed Intake (FI, n=2x16) and egg production (n=2x16) were measured weekly until week 15 (W15) and every two weeks during laying period. Animals were vaccinated against Gumboro disease at day 5 and 30 of age. 45 bird for each treatment were blood collected for Gumboro antibody titration. Results were analyzed using Fisher test (homogeneity) and ANOVA.
Results and discussion: During the rearing period (14 to 105 days), no significant difference was observed between the two groups for LWB (1,094kg ±0,070 vs. 1,095kg ±0,085), respectively for VéO and Control. The homogeneity of the pullets LWB from the VéO group was significantly better (p<0.02) at transition time to production barn (15 weeks of age). The Gumboro immune response was significantly higher (+30 to +50%, p<0.002) after 75 days in the VéO pullets group, suggesting a better efficiency of the immune system.
During the start of the laying phase (W18 to W25), laying rate (LR) increased more rapidly in VéO flocks compared to control ones. During the two last weeks of the trial (W24-25), the LR measured from VéO group was significantly higher (p<0.001) compared to control one (92.5% ±4.6 vs. 86.0% ± 6.7). At the same time, the eggs weight (EW) increased more rapidly than control ones. During the period W24-25, eggs weighed from VéO group were significantly heavier (p<0.002) than control ones, respectively 53.6g ± 0.9 vs. 50.9g ± 1.2. These results suggest that VéO®Premium feed additive helps birds to better adapt themselves to critical periods like the start of laying beginning or peak of it. These performances improvements (LR and EW), from W18 to W25, increase significantly (p<0.01) egg mass production (respectively 28.1kg ± 2.6 vs. 25.1kg ± 2.8). The Feed Conversion Ratio was significantly lower in VéO laying hens compared to control at the same period, respectively 4.27 ± 0.08 vs. 4.64 ± 0.09.
Conclusion and Implications By improving LBW homogeneity at 15 weeks of age, VéO®Premium feed additive generates a positive sensory experience that makes the laying hens better prepared to face transition to laying cages. These results suggest that VéO®Premium has a global effect that allows animals to better adapt themselves to difficult times.
Esch T and Stephano GB. 2004. Neuroendocr Lett. 4(25): 235-251;
Steiger SS. et al. 2008. Proc. R. Soc. B. 275 :2309-2317.
Keywords: laying hens, performances, anti-stress, volatile molecules.
Presented at CLANA 2016.