Effect of adjuvants on in ovo vaccination against Newcastle disease on hatchability, performance and antibody titres in commercial pullets.

This study was conducted to investigate the efficacy of in ovo administration of aluminium hydroxide (AH) and/or mannan oligosaccharide (MOS) adjuvants along with lentogenic VG/GA strain-Avinew to alleviate the embryonic pathogenicity of Newcastle disease virus. Six hundred and thirty fertilized Bovans eggs were divided into nine groups of 70 each incubated in a commercial hatchery and administered with eight types of in ovo injections in a factorial design of 2 × 2 × 2 including with/without AH, MOS and Newcastle disease vaccine (NDV), and one uninjected group on day 18 of incubation. Hatchability was higher in the eggs received MOS and/or AH adjuvants plus NDV compared those injected with NDV alone which confirmed the attenuation of NDV. However, the average daily feed intake and feed conversion ratio of pullets hatched from NDV-injected eggs were significantly reduced, but did not affect growth performance during 0-42 days of age. The performance of pullets hatched from eggs injected with AH, MOS or their mixture with NDV was not significantly different during all growth periods. Pullets from MOS + vaccine injected eggs had significantly higher antibody titres against NDV compared to those hatched from either injected with saline or uninjected on d 28 (p < .05). In addition, AH plus vaccine and MOS significantly improved total anti-SRBC and IgG respectively. Histological observation revealed that injection of MOS adjuvant into eggs led to increase crypt depth, whereas AH injection caused a reduction in villus surface area of jejunum in chicks on d 14 post-hatch. It is concluded that in ovo MOS injection as compared to AH may be more effective to attenuate the embryonic pathogenicity of in ovo NDV injection.

Metabolizable energy and digestible amino acid prediction of wheat using mathematical models.

Wheat is a common raw material used to provide most of the energy and a great portion of amino acids in poultry diets. The routine investigation of metabolizable energy (ME) and digestible amino acid content determination are costly and time consuming for wheat grains. Therefore, it would be helpful if the energy and digestible amino acid content of wheat grain samples could be predicted from their chemical composition. Three studies were conducted to evaluate the probability of AMEn, AME, and apparent ileal digestible amino acid (AIDAA) prediction in wheat samples based on chemical compositions. Multiple linear regression (MLR), partial least square (PLS), and Artificial neural network (ANN) methods were developed to estimate the AME values of wheat grain samples based on total and soluble nonstarch polysaccharides (study 1) and the AMEn based on DM, CP, and ash (study 2). Furthermore, MLR and ANN models were used to estimate the AIDAA via CP content of wheat samples (study 3). The fitness of the models in each study was tested using R2 values, RMS error, mean absolute deviation, mean absolute percentage error, and bias parameters. The results of studies 1 and 2 showed that AME can be predicted from the chemical composition. The prediction of AME of wheat through the ANN-based model showed higher accuracy and lower error parameters as compared with MLR and PLS models in both studies (1 and 2). The results of the third study indicated that CP can be used as a single model input to predict AIDAA in wheat samples. Furthermore, the ANN model may be used to improve model performance to estimate AIDAA as affected by CP content. The results demonstrated that the ANN model may be used to accurately estimate the ME and AIDAA values of wheat grain from its corresponding chemical compositions. As a result, this method provides an opportunity to reduce the risk of an unbalanced level of energy and amino acid in feed formulation for poultry.