ABSTRACT
The aim of this project was to investigate the effect of dietary inclusion of sodium bicarbonate (NaHCO3) on nutrient digestibility and immune response of caged layers during summer when the temperature exceeds 40 ˚C. For immune response trial, White Leghorn layers (n=160; 24 weeks old) were purchased from a poultry farm and were divided into five treatment/diets groups (4 replicate/treatment). Diet A, was without NaHCO3 and served as control whereas, diets B, C, D, and E contained 0.5, 1.0, 1.5 and 2.0% NaHCO3, respectively. All these birds were vaccinated against Newcastle disease (ND) virus at the start of the experiment and thereafter with one-month intervals. Blood samples were collected from two birds/replicate at 10 days post vaccination each time to check antibody titer against ND virus. For digestibility trial, fecal samples were collected (6 layers/treatment group) at the start of the 37th week of age for two days, at 3 hours interval. Results revealed that immune response against ND virus 10 days post vaccination after 1st, 2nd and 3rd month was significantly (p<0.05) higher in layer birds fed diets containing NaHCO3. Digestibility of dry matter (DM), crude protein (CP), crude fiber (CF), ether extract (EE) and absorption of minerals were also found to be significantly (p<0.05) higher in groups treated with NaHCO3 and the birds fed diet containing 1% NaHCO3 showed the best results. In general, results revealed that 1% supplementation of NaHCO3 in layers’ diet have a beneficial impact in terms of immunity and diet digestibility.
Keywords:
Heat stress; Layers; Newcastle disease; Nutrient digestibility; Sodium bicarbonate