An experiment was carried out to evaluate the performance, egg quality and morphometry of the reproductive tract, liver, pancreas and tongue of laying hens submitted to different molting methods. Two hundred and eighty eight 72-week-old Isa brown layers were distributed according to a completely randomized design with six treatments (molting methods) and six replicates of eight birds each. Layers were fed diets containing 3000 ppm zinc oxide, 60 ppm or 120 ppm nicarbazin, 30 ppm or 60 ppm salinomycin, or were submitted to feed fasting. Data were submitted to analysis of variance and means were compared by the test of Tukey at 5% probability level. Molting methods alternative to feed fasting were effective to induce molting in layer and provided good performance results in the second laying cycle.

The objective of the present experiment was to compare the performance, egg quality and organ morphometrics of commercial layers submitted to alternative forced molting methods using dietary fibers. The experimental period included the phases of molting, rest, and second laying cycle (six periods of 28 days each). In the trial, 320 commercial Isa Brown layers with 72 weeks of age were distributed, according to a completely randomized experimental design into five treatments with eight replicates of eight birds each, totaling 40 experimental units. Molting was induced by feeding diets with the inclusion of alfalfa or soybean husks at 80% and 60% or feed fasting. Treatments were applied for 14 days. Performance and egg quality parameters were evaluated for the second laying cycle and organ morphometrics (liver, gizzard, proventriculus, reproductive apparatus) in two different slaughter dates. The obtained data were submitted to analysis of variance using the General Linear Model (GLM) procedure of SAS statistical package (SAS Institute, 2002). Alternative molting methods promoted similar performance and egg quality results after molting were similar to those obtained by the conventional fasting method. Feeding fiber produced the expected effects in terms of organ weight regression and recovery and may be used to induce molting in commercial layers.

An experiment was conducted to evaluate the biometrics of organs (ovary, oviduct, liver, proventriculus and gizzard) of laying hens submitted to different forced-molting methods of molt and maintained at three different temperature. Organs were evaluated after molting and resting period. Six hundred birds were distributed according to a completely randomized experimental design in a 5x3 factorial arrangement (forced-molting methods x environmental temperatures) into 15 treatments with 5 replicates of 8 birds each. The molting methods applied were the dietary inclusion of 90%, 70%, 50% of alfalfa, 2,800 ppm zinc oxide, or total feed restriction. Birds were kept at ±20 ºC, ±27 ºC, or ±35 ºC. Data were submitted to analysis of variance and means were compared by orthogonal and polynomial contrasts. The traditional forced-molting method (feed fasting) resulted in adequate performance. However, as the aim of the present study was to find an alternative method to feed fasting, the highest dietary alfafa inclusion level (90%) was shown to be efficient compared with other methods, particularly when hens were kept at high temperature. Therefore, this alternative forced-molting may be applied, especially when bird welfare is taken into consideration.

One experiment was conducted to evaluate the effect of using different lysine and methionine + cystine levels on body weight recovery, performance, and egg quality of laying hens during the post-molting period. In this trial, 432 Isa Brown layers, with 72 weeks of age, were distributed in 54 cages according to a completely randomized design with six treatments and nine replicates of eight birds each. During the resting period, six diets with different digestible lysine and methionine + cystine levels were used, as follows: 0.48% digestible lysine and 0.43% methionine + cystine; 0.48% digestible lysine and 0.47% methionine + cystine; 0.48% digestible lysine and 0.52% methionine + cystine; 0.56% digestible lysine and 0.50% methionine + cystine; 0.56% digestible lysine and 0.56% methionine + cystine; 0.56% digestible lysine and 0.62% methionine + cystine. Data were submitted to analysis of variance and means were compared at by Tukey’s test at 5% probability level. The different lysine and methionine + cystine levels in the diets fed during the resting period significantly influenced layer performance. The diet containing 0.56% lysine and 0.56% methionine + cystine promoted higher egg weight eggs during the second production cycle.