Effect of level of fiber of the rearing phase diets on egg production, digestive tract traits, and body measurements of brown egg-laying hens fed diets differing in energy concentration

This research studied the effects of additional fiber in the rearing phase diets on egg production, gastrointestinal tract (GIT) traits, and body measurements of brown egg-laying hens fed diets varying in energy concentration from 17 to 46 wk of age. The experiment was completely randomized with 10 treatments arranged as a 5 × 2 factorial with 5 rearing phase diets and 2 laying phase diets. During the rearing phase, treatments consisted of a control diet based on cereals and soybean meal and 4 additional diets with a combination of 2 fiber sources (cereal straw and sugar beet pulp, SBP) at 2 levels (2 and 4%). During the laying phase, diets differed in energy content (2,650 vs. 2,750 kcal AMEn/kg) but had the same amino acid content per unit of energy. The rearing diet did not affect any production trait except egg production that was lower in birds fed SBP than in birds fed straw (91.6 and 94.1%, respectively; P < 0.05). Laying hens fed the high energy diet had lower feed intake (P < 0.001), better feed conversion (P < 0.01), and greater BW gain (P < 0.05) than hens fed the low energy diet but egg production and egg weight were not affected. At 46 wk of age, none of the GIT traits was affected by previous dietary treatment. At this age, hen BW was positively related with body length (r = 0.500; P < 0.01), tarsus length (r = 0.758; P < 0.001), and body mass index (r = 0.762; P < 0.001) but no effects of type of diet on these traits were detected. In summary, the inclusion of up to 4% of a fiber source in the rearing diets did not affect GIT development of the hens but SBP reduced egg production. An increase in the energy content of the laying phase diet reduced ADFI and improved feed efficiency but did not affect any of the other traits studied.

Influence of body weight of the pullets at hatch on egg production at the onset of the subsequent laying period

We studied the influence of pre-incubation weight of eggs (EW) laid by 24 wk-old brown laying breeders on egg production from 18 (start of egg production) to 22 wk of age (average egg production across EW treatments of 87.8%). The experiment consisted in 7 treatments based on the initial EW (47 to 53 g with 1 g difference between groups) Average BW of the extreme groups varied at hatching from 32.5 to 35.4 g, respectively. Feed intake, egg production, and egg weight were recorded weekly by replicate as well as for the entire experiment (18 to 22 wk of age). Hens were weighed by replicate at the beginning and at the end of the experiment. From these data, ADFI, egg production, egg weight, egg mass, feed conversion ratio per kilogram of eggs and per dozen of eggs, and BW gain were calculated by week and for the entire experiment. Also, the number of dirty, broken, and shell-less eggs was recorded daily by replicate in all eggs produced. Data were analyzed as a completely randomized design with 7 treatments differing in the initial pre-hatching EW. Effects of EW on the variables studied were partitioned into linear and quadratic components. EW did not affect the age at which pullets reached 50% egg production, cumulative egg production, or BW gain of the hens from 18 to 22 wk of age. Egg weight and the proportion of dirty, broken, and shell-less eggs were not affected by the BW of the pullets at hatching. In summary, small eggs (>47 g) laid by young, healthy laying breeders, can be used successfully to produce high quality pullets