Effect of dietary inclusion of sodium bicarbonate on production performance, nutrient digestibility and blood profile of caged layers during summer

Abstract

The intent of this study was to investigate the effect of dietary inclusion of NaHCO3 on production performance, nutrient digestibility and blood profile of caged layers during summer. One hundred sixty commercial layers of 24 weeks old were bought from a commercial layer farm and were raised in a group for one week i.e. adaptation period. At the beginning of 26th week of age, these layers were further divided into 20 experimental units/replicates (8 layers/replicate). These 20 replicates/units were further allotted/distributed to five treatment groups (4 replicate/treatment). All the birds were offered diets containing 17% CP and 2700 Kcal/Kg ME with or without supplementation of NaHCO3 for a period of twelve weeks. Group A served as control, which was provided layer ration without any supplementation, while group B, C, D, and E were offered ration supplemented with 0.5, 1, 1.5 and 2% sodium bicarbonate, respectively. All the diets were iso-nitrogenous (having same protein contents, CP, 17%) and iso-caloric (having same energy level, ME, 2700 Kcal/Kg). these diets were fed to the experimental birds ad libitum, for 12 weeks (26-37 weeks of age). Data on feed consumption, number of eggs produced, egg weight and egg mass laid by the birds were recorded. These data were used for the calculation of feed conversion ratios (FCR) on the basis of per dozen eggs and FCR on the basis of per kg egg mass produced. Five eggs from each replicate were checked weekly for their shell thickness (ST), yolk index (YI), albumen index (AI), Haugh unit (HU) score, yolk pH, albumen pH, specific gravity (SG) and yolk cholesterol. Results revealed that dietary inclusion of sodium bicarbonate significantly (P<0.05) increased feed consumption, weight gain, feed efficiency, egg production, egg weight, egg shell thickness, specific gravity, albumen height, Haugh unit, yolk height and yolk diameter of eggs produced by the birds. Yolk cholesterol was found to be minimum in the eggs laid by the birds fed rations containing 1% NaHCO3 (group C). Whilst pH of yolk, egg albumen and Serum uric acid concentration were found to be higher in group E. Dietary inclusion of sodium bicarbonate significantly (P<0.05) decreased the rectal temperature and respiration rate of layers, whilst it increased the water intake of the birds significantly (P<0.05). Blood samples were collected from two birds selected randomly from each replicate 10 days post vaccination of 1st, 2nd, and 3rd vaccination to check antibody titer against ND virus. Blood samples were collected from two birds from each replicate at the last day of 37th week for the analysis of blood profile. Serum glucose, white blood cells count, serum urea, plasma chlorides, serum cortisol and serum glutamic-oxaloacetic transaminase concentration were (SGOT) found to be significantly (P<0.05) higher in control group, whereas, blood hemoglobin concentration, red blood cells count, plasma sodium, potassium, bicarbonate, serum total protein and serum albumen concentration were found to be significantly (P<0.05) higher in birds of group C. However, yolk index, packed cell volume, erythrocyte sedimentation rate, serum creatinine, alkaline phosphatase, plasma calcium, plasma phosphorus, serum globulin and serum glutamic pyruvate transaminase concentration were not affected significantly (P>0.05) due to the dietary treatments. Serum cholesterol, triglycerides and low density lipo-proteincon centration were significantly (P<0.05) decreased, whereas, serum high density lipo-protein concentration was found to be significantly (P<0.05) increased by dietary inclusion of sodium bicarbonate. Birds of group C showed maximum concentration of estrogen, progesterone, T3, T4 and antibody titer against Newcastle disease. For digestibility trial thirty layers having similar body weight were obtained from the same batch which was used for the performance trial. These birds were maintained in individual metabolic cages and were randomly allotted to five experimental diets (same as in performance trial) in such a way that each ration was offered to 6 layer birds and each bird served as a replicate. Feces samples were collected at the end of 38th week of age for two days at the time interval of three hours. Results revealed that digestibility of dry matter , protein, ether extract and crude fiber as well as mineral absorption was found to be better in the birds fed diets containing 1% sodium bicarbonate.