Influence of the main cereal and feed form of the diet on performance and digestive tract traits of brown-egg laying pullets.

The influence of the main cereal and feed form of the diet on performance and digestive tract traits was studied in 576 brown-egg laying pullets from 1 to 120 d of age. From 1 to 45 d of age, 4 diets arranged factorially with 2 cereals (corn vs. wheat) and 2 feed forms (mash vs. pellets) were used. Each treatment was replicated 6 times (24 pullets per replicate). From 46 to 120 d of age, all diets were offered in mash form and the only difference among diets was the cereal used. Cumulatively, pullets fed the corn diets had higher BW gain (P < 0.05) but similar feed conversion ratio as pullets fed the wheat diets. From 1 to 45 d of age, pullets fed pellets consumed more feed (P < 0.001) and had higher BW gain (P < 0.001) than those fed mash. Most of the beneficial effects of pelleting on productive performance were still evident at 120 d of age. At 45 d of age, gizzard weight (g/kg of BW) was higher (P < 0.01) in pullets fed corn than in pullets fed wheat diets. Feeding pellets reduced the relative weight of the digestive tract and the gizzard (P < 0.001) as well as the length (cm/kg of BW) of the small intestine (P < 0.01) at both ages. The pH of gizzard contents at 120 d of age was not affected by cereal but was lower in pullets that were fed mash from 1 to 45 d of age (P < 0.01). We conclude that wheat can be used in substitution of corn in pullet diets with only a slight reduction in BW gain and that feeding pellets from 1 to 45 d of age increased BW gain and pH of the gizzard and reduced the relative weight of the gizzard and the length of the gastrointestinal tract at 120 d of age.

Effects of the levels of methionine, linoleic Acid, and added fat in the diet on productive performance and egg quality of brown laying hens in the late phase of production.

Two trials were conducted to study the effect of reducing the methionine (MET, 0.36 vs. 0.31%), linoleic acid (LIN, 1.60 vs. 1.12%), and supplemental fat (SFAT, 3.0 vs. 1.1%) content of isoenergetic diets on the productive performance and egg quality of brown laying hens late in the production cycle. The 8 treatments were arranged factorially (2 x 2 x 2), with 6 replicates of 20 hens per treatment (Hy-Line, from 59 to 70 wk of age in trial 1, and Lohmann, from 56 to 75 wk of age in trial 2). Except for SFAT content, dietary treatment had little effect on laying hen performance and egg quality. The only effect of a reduction in MET content on hen performance was the decrease in the percentage of large and extra large eggs (79.8 vs. 85.9%; P < 0.05) from 60 to 67 wk of age in trial 2. A decrease in the level of SFAT reduced egg production (79.3 vs. 77.0%; P < 0.05), egg weight (66.3 vs. 64.9 g; P < 0.001), egg mass (52.5 vs. 49.8 g/d; P < 0.001), feed conversion ratio (2.26 vs. 2.36 kg of feed/kg of eggs; P < 0.001), and percentage of extra large eggs (13.1 vs. 8.2%; P < 0.05) in trial 1, but no significant differences were detected in trial 2. Reducing the LIN content of the diet from 1.60 to 1.12% did not affect any trait in either of the 2 trials. We conclude that reducing the level of SFAT from 3.0 to 1.1% might decrease productivity and the percentage of extra large eggs. However, a reduction in the MET level from 0.36 to 0.31% and in LIN from 1.60 to 1.12% did not affect any trait in hens late in the production cycle. Eggshell quality was not affected by any of the dietary treatments.