PERFORMANCE OF LAYING HENS FED DIETS CONTAINING SOYBEAN GUMS, RAPESEED GUMS OR RAPESEED MEALS WITH AND WITHOUT GUMS

Two experiments were conducted to study the effect of soybean and/or rapeseed gums (SBG and/or RSG) on general performance and mortality of laying hens. In exp. 1 a total of 1824 SCWL hens of two commercial genotypes (912 of each) were fed a corn-soy-based control diet or this diet to which was added 2.0% be weight of either SBG or RSG. In exp. 2, 1824 hens of the more sensitive genotype used in exp. 1 were fed a control diet or diets containing approximately 15% of gummed and gumless Tower and Candle rapeseed mean (RSM) or gumless Tower RSM to which was added 3.33% Candle gums. The addition of SBG and RS3 to the diet (exp. 1) caused a significant increase in mortality, increased the amount of feed required to produce a kilogram of eggs, and decreased heart and liver weights. Feeding RSM with and without the commercial level (2.0% of the RSM, or in this study 0.3% of the diet) of added gums had no effect on body weight or egg weight. Hen-housed egg production and feed per dozen eggs were significantly depressed by feeding Candle RSM with gums and by feeding gumless Tower RSM to which had been added Candle gums, indicating that Candle gums but not Tower gums are deleterious to laying hens even at the commercial level of addition to RSM. Accumulated mortality to 497d was significantly higher for all groups fed RSM with or without gums compared to the control-fed group. The increase in mortality with this sensitive genotype appeared to be related to the mere presence of RSM in the diet and not due to the presence of gums per se. The major cause of mortality in both experiments was diagnosed as fatty liver syndrome, and from results of exp. 2 appeared to be related to the presence of RSM in the diet and not due to the presence of gums.