Effects of graded replacement of soybean meal by sunflower seed meal in laying hen diets on hen performance, egg quality, egg fatty acid composition, and cholesterol content

Abstract

Protein feed sources are becoming more and more limited worldwide. Soybean meal, as the primary and most reliable protein source, is becoming increasingly expensive; therefore, there is a need to look for economic alternative protein sources. This trial was conducted to evaluate the effects of graded replacement of soybean meal by sunflower seed meal (SSM) on the performance, egg quality, egg fatty acid composition, and cholesterol content in Rugao laying hens (a local breed). One hundred sixty 28-wk-old laying hens were randomly assigned to 4 groups of 40 birds. Each group was made up of 4 replicate subgroups, with 10 laying hens each. All birds were acclimated to the basal diet for 1 wk. Experimental diets contained 0 (control), 8.26, 16.52, and 24.84% SSM (ME, 8.50 MJ/kg; CP, 33.00%; Ca, 0.26%; P, 1.03%) replacing soybean meal. Feed and water were offered ad libitum for 6 wk. No significant difference (P > 0.05) was observed among treatments in the performance and egg quality of laying hens. The concentrations of saturated fatty acids, monounsaturated fatty acids, and polyunsaturated fatty acids in yolks were consistent among the diets, except that the percentage of C17:0 decreased in the yolks of birds fed the experimental diets (P < 0.05). However, after 6 wk of feeding, the egg yolk cholesterol concentrations of birds in the experimental groups were lower than those of birds in the control group (P < 0.05). Thus, it could be feasible to use SSM in laying hen diets as an available ingredient replacing soybean meal, without affecting performance or egg fatty acid content while reducing the cholesterol level in the yolk and the production cost.