Influence of <i>Citrus sinensis</i> Seeds on the Growth Performance, Ceca Bacterial Population and the Immune System Response of Broiler Chickens

The restriction of the use of antibiotics in animal production as a growth promoter due to pathogens resistance and residues in poultry products leads to the use of phytogenics as feed additives, an alternative that is attracting increasing interest nowadays. This study was carried out to investigate the effect of milled orange seeds supplemented into a broiler diet on the gut microbiota and the response of the immune system. A total of 720-day-old broiler chicks were divided into six treatment groups of six replicates, each containing 20 chicks. The dietary treatments were as follows: (1) Basal diet (Con-1 or negative control), (2) Basal diet + 0.01% of neomycin (Con-2 or positive control), (3) Basal diet + 0.5% of the orange seeds (0.5% CSS), (4) Basal diet + 1% orange seeds (1% CSS), (5) Basal diet + 2% orange seeds (2% CSS), (6) Basal diet + 4% orange seeds (4% CSS). The results showed that the supplementation of Citrus sinensis seeds at 0.5% significantly decrease coliforms population in the ceca compare to the positive group. There was a decrease (p < 0.05) in the population of caecal lactobacilli in the positive control group (antibiotic) compared to the negative control group and the groups of C. sinensis seeds. The birds in the 4% CSS group had higher (p < 0.05) IgG concentrations than the positive control and 0.5% CSS groups. The response of the immune system was not affected by orange seed supplementation. It was concluded that the supplementation of 0.5% of orange seeds in the diet of broilers optimize the population of bacteria in the ceca.