Dicalcium phosphate nanoparticles (nano-DCP) were synthesized by physical method using ball mill. The synthesized DCP nanoparticles were characterized by various techniques viz. Particle size analyser, Zeta potential, Transmission Electron Microscopy (TEM), X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR) and Energy Dispersive Analysis by X-ray (EDAX). The results revealed that synthesized nano-DCP had particle size between 10-20 nm and zeta potential value of -25.6±2.2 mV. Crystal size of nano DCP analysed by XRD was 29.31 nm. Calcium and phosphorus content of synthesized nano-DCP were 23.22 and 17.67 per cent. Ball milling, a popular physical method and is easy to operate, economic, time saving and higher yield. Based on its bioavailability, the synthesized feed grade nano DCP can be utilized for in ovo feeding of broiler embryos, livestock and poultry feeding.

Supplementation of antibiotics in poultry diet was banned in several countries due to development of antibiotic resistance. In ovo feeding of prebiotics, probiotics and synbiotics have gained more attention recently. The present study was carried out in 2018 to investigate the effect of in-ovo feeding of probiotic, prebiotic and symbiotic on growth performance and gut microbiome of broiler chicken. On 18th day of incubation, 600 eggs were randomly divided into five treatments each with four replicates of 30 eggs each and were injected with different bio-active compounds, viz. 0.2 ml of Lactobacillus acidophilus 3×107 cfu, 0.5% Mannan-oligosaccharide (MOS), synbiotic (0.1 ml each of Lactobacillus acidophilus 3×107 cfu and 0.5% MOS) along with injected and non-injected controls. After hatch, 400 chicks were sorted out as per treatment with four replicates of 20 chicks each. Birds were reared under deep litter system and fed with experimental diet ad lib. In ovo feeding of Lactobacillus acidophilus, MOS either separately or in combination significantly improved hatch weight, fifth week body weight and gain. However, hatchability, cumulative feed intake, cumulative FCR and cumulative livability were not affected. Improved colonization of Lactobacillus acidophilus and suppressed colonization of Salmonella, Escherichia coli and Staphylococcus in all intra-amniotic groups was noticed. Ileal Mucin-2 gene was significantly up-regulated in the order of MOS, L. acidophilus and synbiotic injected broilers. The results concluded that the in ovo delivery of Lactobacillus acidophilus and MOS either separately or in combination had beneficial effect on growth and gut health of broiler chicken.

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