Nutrient retention and production parameters of Single Comb White Leghorn layers fed diets with varying crude protein levels and supplemented with direct-fed microbials

Four hundred and eighty Dekalb XL Single Comb White Leghorn layers (30 weeks of age) were fed five diets for eight 28-day periods in a completely randomized split-plot design to determine the effects of feeding Lactobacillus (Lacto) with varied dietary protein levels on the retentions of fat (ether extract), nitrogen, calcium, and phosphorus, and on layer performance. The five dietary treatments were 13.8%, 14.3% and 15.3% crude protein (CP) diets each supplemented with 1100 mg Lacto per kg (4.4 x 10(7) colony forming units) and 15.3% CP diet supplemented with and without condensed cane molasses solubles (CCMS) which served as a carrier for the Lacto in a premix. The CCMS-Lacto premix was incorporated at 2% of the diets. Linear contrasts for hen-day egg production and daily feed consumption were not significant with CCMS-Lacto supplementation regardless of the dietary protein levels. Layers fed the 15.3% CP CCMS-Lacto diet laid significantly (P < 0.05) larger size eggs than those on 15.3% CP CCMS diet. Feed conversion, egg mass, egg weights and egg size were higher(P < 0.05) for layers fed the 15.3% CP CCMS-Lacto diet than 14.3 and 13.8% CP CCMS-Lacto diets, Interior egg quality and egg shell thickness were not different with layers fed CCMS-Lacto supplementation diets. Egg yolk color scores were highest (P < 0.05) from layers fed CCMS-Lacto diets with 13.8% CP diet. Fat and phosphorus retentions were higher with CCMS-Lacto supplementation and with change in dietary CP levels from 15.3% to 14.3% in CCMS-Lacto supplemented diets, respectively.