Comparison of peanut meal and soybean meal as protein supplements for laying hens

Peanut protein is severely limiting in threonine and has been used to create threonine deficiency in animals. The availability of purified threonine at low cost raises the possibility of economically using peanut meal (PNM) and threonine combinations in poultry diets. An experiment was conducted to compare corn and PNM based diets to corn and soybean meal (SBM) based diets at three protein levels (16, 18.5, and 21%) in diets for 22-to-34-wk-old commercial Leghorns. Birds were housed two per cage with four cages per replicate and six replicates per treatment. Feed consumption, egg production, and feed per dozen eggs were almost identical for PNM (93.8 g/hen per d, 92.2 eggs per 100 hens/d, and 1.22 kg/dozen) and SBM (93.7 g/hen per d, 92.2 eggs per 100 hens/d, and 1.22 kg/dozen). Dietary protein level had no consistent effect on any of these parameters but did significantly improve body weight gains and egg weights (1.2 to 2.5 g/egg). PNM-fed hens laid slightly smaller eggs during the first 6 wk (P<0.05), but there were no egg size differences during the last 6 wk of the experiment (P>0.14). PNM-fed hens laid eggs with better interior quality at 26 and 30 wk of age. After 2 wk of storage, Haugh units remained better for eggs from hens fed PNM than SBM when kept refrigerated (4 degrees C; P<0.05) or at room temperature (20 degrees C; P<0.10). Egg specific gravity was slightly lower for hens fed PNM. It is concluded that PNM is an excellent ingredient for laying hen diets.