Intra-Amnionic Threonine Administered to Chicken Embryos ReducesEnteritidis Cecal Counts and Improves Posthatch Intestinal Development.

Abstract

This study assessed the effect ofthreonine supplementation on the response of broiler chicks challenged withEnteritidis, considering bacterial counts in cecal contents, intestinal morphology, body weight, and weight gain. Fertilized eggs were inoculated in the amniotic fluid with saline (NT) or 3.5% threonine (T) solution at day 17.5 of incubation. At hatch, chicks were individually weighed and cloacal swabs were screened for. At 2 days of age, half of the birds from eachtreatment were given either 0.5 mL of nutrient broth (sham-inoculated) or nalidixic acid-resistantEnteritidis (SE Nal) in nutrient broth (8.3 × 10colony forming units (CFU) SE Nal/mL). The birds were distributed using a completely randomized design with four treatments after thechallenge: noThr supplementation and sham-inoculated in the posthatch challenge (NT-SHAM),Thr supplementation and sham-inoculated (T-SHAM), noThr supplementation and SE Nal-challenged (NT-SE), andThr supplementation and SE Nal-challenged (T-SE).threonine supplementation reducedEnteritidis colonization 168-hour postinoculation and reduced the negative effects associated withinfection on intestinal morphology and performance, with results similar to those of the sham-inoculated birds.Thr supplementation increased the expression ofat hatch and the expression ofandat 2 days of age and 168-hour postinoculation. Our results suggest that providingthreonine promotes intestinal health in broilers challenged withEnteritidis in the first days of life.