ABSTRACT The relationships between egg measurements [egg weight (EGWT), egg width (EGWD), egg shape index (EGSI), egg volume (EGV) and egg density (EGD)], and egg components [eggshell (SWT), yolk (YWT) and albumen (AWT)] were investigated in laying hens with 32, 45, and 59 weeks of age with an objective of managing multicollinearity (MC), using stepwise regression (SR) and ridge regression (RR) analyses. There were significant correlations among egg traits that led to MC problems in all eggs. Hen age influenced egg characteristics and the magnitude of the correlations among egg characteristics. Eggs produced at older age had significantly (p<0.01) higher EGWT, EGWD, EGV, YWT and AWT than those produced at younger age. The SR model alleviated MC problem in eggs produced at 32 weeks, with condition index greater than 30, and one predictor, EGWT had a model fit predicted egg components with R2 ranged from 60 to 99%. The SR model of eggs produced at 45 and 59 weeks indicated MC problem with variance inflation factors (VIF) values greater than 10, and 4 predictors; EGWT, EGWD, EGV and EGD had a model fit that significantly predicted egg components with R2 % ranged from 76 to 99 %. The RR analysis provided lower VIF values than 10 and eliminated the MC problem for eggs produced at any age group. It is concluded that the RR analysis provided an ideal solution for managing the MC problem and successfully predicting egg components of laying hens from egg measurements.

A study was undertaken to evaluate the effects of Neoxyval (antimicrobial growth promoter (AGP)), TechnoMos (prebiotic), GalliPro (probiotic) and a mixture of TechnoMos and GalliPro (symbiotic) on growth performance, carcass yield, histomorphology and intestinal bacterial counts in broilers (0 d to 42 d). Two hundred day-old Ross (308) broilers were allocated to five experimental treatments: T1 = control (CONT), T2 = T1 + Neoxyval, T3 = T1 + Gallipro, T4 = T1+ TechnoMos and T5 = T1+ Gallipro+ TechnoMos. The results revealed that birds that received T2, T4 and T3 gained more weight and converted feed more efficiently than those in T1 and T5. Longer ileal villi (492.9 μηι) were recorded in birds that received T4 compared with T1 (424.7 μπι) and T2 (439.9 μπι). Conversely, jejunal villi length and width were not influenced by treatment. T3 eliminated Clostridium perfringens from the ileum, but not from the caecum. Generally, birds that received T3 and T5 performed similar to the AGP group, T2. The results from this study indicated that the probiotic (T3) and prebiotic (T4) used in this trial could serve as alternatives to AGP (T2). Enhancement in the performance of broilers could be explained partially by improvement in intestinal morphology and microbial balance associated with modulation of intestinal microflora and inhibition of pathogens.

Two trials were conducted to investigate the effects of exposing layer-type breeder eggs before incubation to ultrasonic waves (ULT). Eggs were subjected to ULT of 117 volts at 40 kHz for up to 15 minutes. Eggshell breaking force (EBF), hatchability and chick hatching weight (CHW) of Balady breeder eggs (Trial 1), and egg weight loss, embryo weight, hatchability and CHW of Leghorn hen eggs (Trial 2) were measured. In Trial 1 the eggs were subjected to seven treatments: non-dipped (control), and dipped for 5, 10 and 15 minutes in a water bath (W5, W10 and W15) or a ULT bath (ULT5, ULT10 and ULT15). In Trial 2 the eggs were subjected to four treatments, a control (ULT0) and the ultrasonic treatments, ULT5, ULT10 and ULT15. In treatments ULT10 and ULT15 the EBF of Balady eggs was significantly reduced while the hatchability of the Balady and Leghorn eggs was significantly reduced by the ULT15 and W15 treatments, compared with the control. Orthogonal contrast (control vs. ULT) indicated that ULT exposure of eggs reduced their EBF significantly. Percentage egg weight loss, embryo weight and CHW was not affected by the treatments. It was concluded that exposure of eggs to ULT of 117 volts at 40 kHz for 15 minutes reduced EBF and hatchability of layer-type breeder eggs without altering egg weight loss, embryo weight or CHW.