A study was conducted to understand utilization of high-oleic soybeans to produce full-fat, high-oleic soybean meal for use as a potential feed ingredient in layer hen diets for added nutritional value in eggs. Forty-eight layers (~36-week-old) were randomly assigned to one of 4 isonitrogenous (18% crude protein) treatment diets (1-4) with 12 replicate birds/treatment in a 3-week study as follows: (1) Solvent extracted defatted soybean meal + corn diet, (2) dry extruded defatted soybean meal + corn, (3) full-fat soybean meal + corn, (4) high-oleic full-fat soybean meal + corn diet. Apparent ileal digestibility of crude fat (CF) and crude protein (CP) were studied using celite (~ 2 %) as an indigestible marker. Tibia strength and other egg quality parameters (egg weight, shell strength, Haugh unit, etc.) were recorded during the study. Enrichment of monounsaturated fatty acid, oleic acid (C18:1, cis), in adipogenic tissue (fat pad, liver, and breast muscle) and in eggs were measured using gas chromatography (GC-FID). Digestibility values of CF ranged from 75-84 % and CP varied from 67-72 % for treatment diets, with treatment mean values being no different (P>0.05) between treatment diets. No differences between treatment diets for tibia strength, egg weight, shell strength or Haugh unit were observed except for yolk color. Similarly, there were no difference in the total fats in fat pads, liver, muscle, and egg yolk (P>0.05) between treatment diets. However, the oleic acid % of total fat for treatment 4 diet in fat pads, liver, muscle, and in egg yolk were 45.73 %, 47.53 %, 31.74 %, and 50.68 %, respectively, and were significantly higher (P ≤ 0.003) than other treatment diets. No difference was observed in oleic acid % of total fat in the adipogenic tissue or eggs in other three treatment diets, 1-3 (P > 0.05).
The results strongly showed that adipogenic tissue and egg quality in terms of oleic acid profile was significantly improved with full fat high oleic acid diet while its digestibility for CF or CP was similar as defatted SBM or full fat SBM diets.