BackgroundHorticultural byproducts may be used to partially or completely replace more expensive soy and corn while providing adequate energy and protein for broilers and laying hens. Probiotics, such as lactic acid bacteria, may aid in digestion of fibrous byproducts such as sunflower seed meal containing complex carbohydrates that along with some amino acids may not be easily digested by monogastric animals. Thus, byproducts and probiotics, when fed to poultry, may improve the production of nutritious meat and eggs. ResultsWhite Leghorn Crosses (64 layers at 65- to 74-wk-old) were fed one of four diets for four weeks. Diets were (1) a corn/soy Control, (2) Control + 20% sunflower seed meal (SFM), (3) Control + Probiotics (Lactobacillus plantarum, rhamnosus, and paracasei - each at > 23.3 Mil CFU/g for a total of approximately 70,000,000 Mil CFU/g added in drinking water), and (4) Control + 20% SFM + Probiotics. Significance (P < 0.05) and trends (P < 0.10) were determined for production measurements as well as external and internal egg quality parameters. Diet did not significantly affect production measurements. There were trends due to Probiotics*Week for FCR and SFM*Probiotics*Week for feed intake. For external egg quality, SFM significantly increased egg weight, decreased specific gravity, and caused a downward trend for egg shell thickness. SFM*Week produced a significant effect on specific gravity. Probiotics significantly increased egg weight and egg shell weight while decreasing egg shell thickness; there was a trend due to temporal effects on specific gravity. For internal egg quality, SFM, SFM*Week, Week, and SFM*Probiotics*Week significantly affected yolk color. Week affected all internal measurements and SFM*Week caused weekly fluctuations, thereby producing a trend for Haugh unit. ConclusionsDiet had no effect on production measurements. SFM increased egg weight and decreased specific gravity; Probiotics increased egg weight, shell weight, and shell thickness. Future research in needed to assess production and egg quality parameters when feeding various fiber types, the digestibility of SFM/Probiotic diets, and colonization of varying quantities of probiotics (added in water and feed) in the gut of various types and ages of laying hens.