Efficacy of in ovo feeding with Lactobacillus acidophilus and oregano essential oil in improving growth performance, immunity, microbial enumeration, and gene expression of ostrich chicks

Abstract

The present study investigated the effect of in-ovo injection of Lactobacillus acidophilus, oregano essential oil, and their mixture on growth performance, antioxidant status, immunity, microbial population, and gene expression in ostrich chicks during summer. On day 36.5 of incubation, 500 fertile embryonic ostrich eggs were distributed equally into five groups. The first group included untreated eggs (PCN), the second group included in-ovo injected with distilled water (NCN), and the third, fourth, and fifth groups included in-ovo injected with L. acidophilus (LA), oregano essential oil (OEO), and their mixture (LOM), respectively. At hatching, 25 ostrich chicks from each group were randomly divided into 5 replicates. Adding L. acidophilus and oregano essential oil mixture to ostrich eggs increased body weight gain and decreased feed conversion ratio compared to the other groups in week 12. The administration of L. acidophilus and oregano essential oil mixture to ostrich eggs resulted in stronger antioxidant defense systems through increasing SOD levels and decreasing MDA levels. L. acidophilus and oregano essential oil mixture enhanced immunity and liver function by increasing the IgA and IgM levels and reducing the AST levels. Furthermore, the L. acidophilus and oregano essential oil mixture enhanced gut health via modifying the microbial content (increased Lactobacillus counts) and gene expression by upregulating the IL-10 and MUC2 genes and downregulating the IL-6 gene. Therefore, our study concluded that the in-ovo L. acidophilus and oregano essential oil mixture enhanced the ostrich chick's growth performance, immune response, and gut integrity during summer. However, further studies are needed to track the effects of these supplements on the growth and health of adult ostriches.