Response of Egg-type Chicks to Mannanoligosaccharides Supplementation of Diets Varying in Energy and Protein

A study was conducted to evaluate the effects of dietary inclusion of mannan-oligosaccharides (MOS) at different energy and protein level on performance of egg-type chicks during hot-dry summer. After feeding a standard diet from 0-21d of age, the chicks were randomly distributed into four dietary treatment groups viz., T₁ with high energy 2800 kcal ME/kg and high protein 18.00% (HEHP), T₂ with HEHP diet and MOS @ 0.2% (HEHP+MOS), T₃ with low energy 2700 kcal ME/kg low protein 17.34% (LELP) and T₄ with LELP diet and MOS @ 0.2% (LELP+MOS). Each treatment had fifty birds divided in five replicates of ten birds each. Experiment was carried out during hot-dry summer (April-May, 28.0±0.12 to 35.25±0.37°C, RH, %: 68.95±0.90 to 79.15±0.61). Production performance, yield of immune organs, blood biochemical and intestinal morphometry were measured on 42^nd and 63^rd day posthatch. Feed intake and feed conversion ratio (FCR) improved significantly (P<0.05) in HEHP+MOS group. H: L ratio significantly (P<0.05) reduced in MOS supplemented group at 42^nd as well as 63^rd day of age. Immune organ like thymus, spleen and bursa had significantly (P<0.05) higher weight in MOS supplemented group. Total protein (P<0.001), AST (P<0.001), ALT (P<0.001) and, creatinine (P<0.05) were significantly improved while cholesterol, uric acid and ALP was significantly (P<0.001) reduced in MOS supplemented diets. Villus height and crypt depth improved significantly (P<0.001) in MOS supplemented group at 42^nd as well as 63^rd day of age. Thus, it may be concluded that high-energy (2800 kcal ME/kg) and high protein (18% CP) diet was beneficial for egg-type starting chicks during dry summer. Moreover, the inclusion of mannan-oligosaccharides @ 0.2% gave further advantage for improved performance and reduction of thermal stress.