Administration of a bacterial mixture to bb chicks: Safety and effects on general growth parameters

Abstract

In Argentina, poultry feeds mainly contain soybean, corn, wheat, aminoacids, salts and growth factors. The vegetable components of these diets include highly resistant to heat and proteolysis proteins called lectins, which act as a defence mechanism in plants against the attack of predator organisms. These proteins produce negative effects on the animals that eat them: diminished digestive enzyme activities and harmed intestinal epithelial cells. This leads to an inefficient use of proteins, which is particularly relevant on the early life of chicks, when protein consumption is crucial for weight gain. In previous studies, four strains (P. acidipropionici LET103, L. salivarius LET201, L. reuteri LET210 and B. infantis CRL1395) were selected for their safety, in vitro probiotic properties and ability to bind to deleterious dietary lectins. E. faecium LET301 was included in the study due to its ability to bind to WGA. Thus,the aim of this work was to confirm the safety of a mixture of four strains administered to BB chicks as a probiotic supplement against lectins, and analyze its effects on general growth parameters along with E. faecium LET301. To this effect, the five strain mixture was daily administered to newly hatched BB chicks in their drinking water (106 CFU/mL of each strain), for three weeks (GT). A group without the bacterial mixture supplement was included as control (GC). Feed consumption and mortality were daily noted. On the 3, 13 and 20 days of treatment, chicks were weighed and sacrificed, and translocation to liver and spleen, liver and spleen weights, and the activity of digestive enzymes (alkaline phosphatase, amylase, leucine aminopeptidase, maltase, protease and sacarase) were analyzed. Feed conversion was evaluated weekly. The animals of group GT had significantly higher (p < 0.05) weight than those of group GC from the 10 day. The feed conversion of the whole period was significantly (p < 0.001) lower for the animals of group GT. No translocation to liver or spleen was observed. Amylase activity was significantly higher (p < 0.05) for the chicks of group GT on the 6 day. Alkaline phosphatase activity was significantly higher (p < 0.01) on the 6 and 13 days for the group GT. Leucine aminopeptidasa presented significantly higher activity (p < 0.05) for the group GT on the 13 day. Maltase activity was significantly higher (p < 0.05) for the animals in group GT on the 3, 6 and 13 days. On the other hand, protease and sacarasa activities showed no differences between the chicks of both experimental groups. In conclusion, the bacterial mixture increased the weight gain and the activity of several digestive enzymes, and decreased food conversion, proving to be not only safe, but also to exert a positive effect on the animals. Nevertheless, the intermediate resistance E. faecium LET301 to clindamycin should be further studied, although the of this resistance on the poultry health is currently unknown.