Bacillus subtilis in ovo improves the weight of post hatch chicks

The final period of incubation and post hatch, are characterized by fast physic and functional development of the digestive tract, which can be influenced by additives. The weights of the liver and gut provides a support to metabolic responses of these organs, as well as, the weight of the yolk sac at birth presents the absorption efficiency of nutrients by the chick, which also can be influenced by exogenous components. The aim of this study was to evaluate the effect of Bacillus subtilis on absolute and relative weight of liver, gut and yolk sac of post hatch chicks. We used 500 fertile eggs (Cobb(R)), from broiler breeder hens at 43 weeks old, within the range of egg weight of 66 ?2 g distributed homogeneously in five incubators with temperature, turning and moisture automatic control. The eggs were distributed in randomized block design with five treatments with 100 eggs each: control (eggs not inoculated) and eggs inoculated with 0,1 mL of Bacillus subtilis in four treatments, control, 10⁶CFU, 10⁷CFU and 10⁸CFU. At 18 days old was carried the candling to remove the infertile eggs and the fertile eggs were injected into the air sac according with treatments. At birth, ten male chicks per treatment were anaesthetized with CO2 and sacrificed by cervical dislocation to remove liver, gut and yolk sac. The samples were weighted and after was calculated the relative weight in relation absolute weight. The data were analyzed using the mixed model with fixed effect of treatments and the random effects of incubators. In case of significant effect, the comparison of the averages was performed using 5% probability of Tukey test. There was no significant effect (p> 0.05) of the treatments on the absolute and relative weights of the liver, gut and yolk sac. The data indicates that inoculation of Bacillus subtilis in the air sac don't affect the yolk sac absorption, as well as, don't influence in the metabolism of liver and gut. These results provide that the bacillus can be inoculated in the air sac of fertile eggs without causing outbreaks of infection, however, more studies regarding the dosage should be performed.