Amino Acid Digestibility and Energy Value of Bitter Vetch (a Cheap Plant Protein) and Effects of Feeding this Plant Protein on Production and Egg Quality

Three experiments were conducted to evaluate the nutritional value of bitter vetch. experiment 1 was con-ducted to determine the metabolisable energy content of bitter vetch. sixteen adult leghorn roosters were used. forty grams of bitter vetch were precision-fed individually to 12 roosters. in addition, 4 birds were not fed and served as a control treatment in the measurement of metabolic fecal and endogenous urinary energy output. experiment 2 was a broiler chick bioassay carried out with 24 male boiler chickens (21-d-old) to determine apparent amino acid digestibilities of bitter vetch. experiment 3 was conducted to evalu-ate the effect of bitter vetch on performance and egg quality of two strains of laying hens. a control diet based on corn and soybean meal and diets containing 50, 100 and 150 g kg-1 bitter vetch were fed to the leghorn layers, isa-babcock strain, and the native strain. all eggs produced during the last 3 d of each month were collected to evaluate egg quality. true metabolisable energy (tme) and nitrogen-corrected true metabolisable energy (tmen) values of bitter vetch were 3396 and 3852 kcal/kg dm, respectively. second experiment showed that the average amino acid digestibility of bitter vetch (12 amino acids) was 66.65%. feed intake, egg weight, egg production, and egg mass, were higher and feed conversion ratio was lower in the leghorn than the native strain. feed intake and egg production were lower and feed conversion ratio was higher by all bitter vetch diets compared with the control diet. haugh unit and yolk color were lower (p < 0.001) in the leghorn than the native strain and vice versa in egg shell weight (p < 0.001). eggshell thickness and shape index were not affected by strain (p > 0.05). it was concluded that 5% of bitter vetch can be used in laying hen diets without any adverse effect.