The effect of dietary wheat middlings and enzyme supplementation. 1. Lateegg production efficiency, egg yields, and egg composition in two strains of leghorn hens

A study was conducted to test the effects of wheat middlings (WM) with and without enzyme (xylanase and protease) supplementation on late egg producti on (EP), egg yields, and egg composition in two strains of Leghorn hens (De Kalb Delta and Hisex White). Six diets were randomly assigned to 300 birds (150 birds per strain) from 42 to 60 wk of age. Diet 1 was a corn-soybean m eal control, Diets 2 and 3 had 8 and 16% WM, respectively, Diet 4 had 8% WM , with 0.1% enzyme, and Diets 5 and 6 had 16% WM with 0.1 and 0.2% enzyme, respectively. Each dietary treatment was replicated five times per strain. Egg production, feed consumption (FC), feed efficiency (FE), percentage dir ty eggs, specific gravity (SP), egg weight (EW), and egg mass (EM) were mea sured on a weekly basis. Egg components (EC) were measured biweekly and bir ds were weighed every 4 wk. Egg production was not significantly affected b y diet, with averages of 83.7, 85.7, 84.1, 84.2, 82.3, and 84.0% for Diets, 1, 2, 3, 4, 5, and 6, respectively. Strain had a marked effect on FC, with Hisex having higher FC than DeKalb hens. Feed consumption also showed a si gnificant diet by strain effect, being lower for Hisex hens fed diets with enzyme compared to diets without enzyme. DeKalb hens had better FE than His ex hens, and addition of enzyme to 16% WM improved it further. Strain and d iet had a significant effect on EC with higher percentages of albumen and y olk for diets with enzyme and for DeKalb hens. Percentage shell was lower f or DeKalb hens than for Hisex hens but was not affected by diet. There was also a significant increase in EW for Diets 4 (63.1 g), 5 (63.8 g), and 6 ( 63.2 g) compared to Diets 1 (62.1 g), 2 (62.4 g), and 3 (63.0 g), with DeKa lb hens showing an increase with Diet 5 compared to Hisex hens. Egg mass im proved with the higher rate of enzyme in 16% WM diet compared to the lower enzyme level. Specific gravity declined with enzyme supplementation in WM d iets. Eggs from DeKalb hens had lower SP than those from Hisex hens for all diets. Percentage dirty eggs did not differ significantly among treatments but was higher for the Hisex strain than for the DeKalb strain. There were no differences in BW between the two strains of hens or among diets. Addin g protease and xylanase to diets rich in fiber can improve the egg output w ithout affecting production parameters.