Pre-hatching temperature training improves performance in dual- and laying-type cockerels fed with different protein and energy concentrations

Abstract

The hypothesis of the present study was that pre-hatching temperature training (PTT) with short-term warm stimulation might improve hatching results and have long-lasting effect on growth performance, production efficiency, and robustness in laying-type and dual-purpose cockerels. Further, during the growth period these results may be modified by the protein and energy level of the diet. A total of 2880 eggs (Lohmann Brown-LB/Lohmann Dual-LD) were incubated from day 1 to 17 under normal incubation temperature (37.2–37.4°C) and until hatching in two groups with different temperature programs (control: 37.2–37.4°C or PTT: plus 1°C above standard for 2 h daily). For a subsequent 70 days growing period, 160 LB and 160 LD cockerels from each incubation group were randomly distributed in 8 treatments (8 pens/treatment; 10 birds/pen) resulting from two genotypes of cockerels, two incubation programs, and two dietary protein/energy levels (200 g crude protein/11 MJ AME N/kg – low level, LL; 215 g/12 MJ – high level, HL). PTT had no negative effect on hatching results in LB and LD cockerels. The origin of cockerels had a significant effect on feed intake, growth performance, and feed to gain ratio. The final body weight at day 70 was 85% higher in LD than in LB cockerels (2500 g/1351 g). In LD, but not so pronounced in LB cockerels, performance and production efficiency were significantly improved by PTT. In LD cockerels, the final body weight on day 70 reached in the LL and HL fed groups 2558 and 2528 g, respectively (control: LL 2432 g/HL 2482). Over the total growing period the feed to gain ratio was 10% higher in the LL fed LB/LD groups (2.56/2.29 kg/kg) compared with the HL groups (2.30/2.06 kg/kg). From day 1 until 49, the lowest feed to gain ratio ( P<0.05) of 1.81 kg/kg was calculated for the PTT group of LD cockerels fed with HL feed. Slaughter after 70 days showed significant differences in breast meat and legs, and percentage of abdominal fat between bird genotype and of the different incubated groups. While the thyroid weight was influenced by genotype only, the bursa weight depended also on experienced PTT at the age of 70 days. Possibly, robustness and therefore stress- and immune response might benefit from PTT in both LD and LB cockerels as indicated by increased mean relative bursa weight of 18 and 21%, respectively.