Three hundred and ninety Hy-Line W36 commercial laying hens, 46 wk of age, were assigned randomly to 13 dietary treatments for 140 d. Hens were housed in cages (2 hens per cage of 25 × 40 cm) in an open-sided house and were fed diets containing 3% of different fat sources (canola oil, sunflower oil, flaxseed oil, fish oil, and a mixture of 50% flaxseed oil plus 50% fish oil) and 9% ground flaxseed with 2 levels of vitamin E (12 and 100 IU/kg) in a factorial arrangement with 5 replicates of 6 hens each. A control diet, using soybean oil, was also fed. Concentrations of saturated (S), monounsaturated (M), and polyunsaturated fatty acids (PUFA), cholesterol, vitamin E, and sensory analyses of the eggs were measured. The results showed that the lipid profile in the yolk was modified by fat sources. Cholesterol content was slightly reduced by the inclusion of greater quantities of unsaturated fatty acids in the diet. Vitamin E concentration in eggs was related to corresponding dietary levels. There was no influence of the treatments on egg flavor. These findings indicate that is possible to improve the nutritional value of eggs by using flaxseed and increasing the vitamin E content of the diet.

Three hundred and ninety Hy-Line W36 commercial laying hens, 46 wk of age, were fed diets containing 3% of different fat sources (canola oil, sunflower oil, flaxseed oil, fish oil, and a mixture of 50% flaxseed oil plus 50% fish oil) and 9% ground flaxseed with 2 levels of vitamin E (12 and 100 IU/kg) in a factorial arrangement with 5 replicates of 6 hens each. A control diet using soybean oil was also fed. Various characteristics of performance, including internal and external egg qualities were measured. The results indicated no influence of the treatments on feed intake, egg production, egg mass, egg weight, feed conversion, yolk color, Haugh units, yolk index, yolk and albumen percentages, and eggshell thickness. Eggshell percentage and egg specific gravity were reduced when hens were fed diets containing 100 IU of vitamin E/kg. The source of fat or level of vitamin E did not affect performance and egg internal quality characteristics.

Two experiments were conducted with Hy-Line W36 hens to evaluate their Thr requirement in a corn-soybean meal diet. Eight experimental diets were used in Experiment 1 with graded levels of Thr: 0.53,0.50, 0.48, 0.45, 0.42, 0.40, 0.37, and 0.35%. Seven experimental diets were used in Experiment 2 with graded levels of Thr: 0.58, 0.53, 0.50, 0.48, 0.45, 0.42, and 0.40%. Supplemental amino acids (AA) were added to all diets to ensure that Thr was the first-limiting AA. Egg production (EP), egg mass (EM), and daily Thr intake were significantly increased with increasing dietary Thr levels. Broken-line regression indicated a daily Thr requirement of 439.0 and 462.1 mg per hen per d in Experiment 1 and of 393.9 and 447.1 mg per hen per d in Experiment 2 for EP and EM, respectively. The Thr requirements to produce 1 g of EM were 8.76 and 9.44 mg in Experiments 1 and 2, respectively.

The aim of this study was to evaluate the viability of the use of spent laying hens' meat in the manufacturing of mortadella-type sausages with healthy appeal by using vegetable oil instead of animal fat. 120 Hy-line® layer hens were distributed in a completely randomized design into two treatments of six replicates with ten birds each. The treatments were birds from light Hy-line® W36 and semi-heavy Hy-line® Brown lines. Cold carcass, wing, breast and leg fillets yields were determined. Dry matter, protein, and lipid contents were determined in breast and leg fillets. The breast and legg fillets of three replicates per treatment were used to manufacture mortadella. After processing, sausages were evaluated for proximal composition, objective color, microbiological parameters, fatty acid profile and sensory acceptance. The meat of light and semi-heavy spent hens presented good yield and composition, allowing it to be used as raw material for the manufacture of processed products. Mortadellas were safe from microbiological point of view, and those made with semi-heavy hens fillets were redder and better accepted by consumers. Values for all sensory attributes were evaluated over score 5 (neither liked nor disliked). Both products presented high polyunsaturated fatty acid contents and good polyunsaturated to saturated fatty acid ratio. The excellent potential for the use of meat from spent layer hens of both varieties in the manufacturing of healthier mortadella-type sausage was demonstrated

The objective of this work was to investigate adjustments of the Gompertz, Logistic, von Bertalanffy, and Richards growth models, in male and female chickens of the Cobb 500, Ross 308, and Hubbard Flex lines. Initially, 1,800 chickens were randomly housed in 36 pens, with six replicates per lineage and sex, fed ad libitum with feed according to gender, and bred until 56 days of age. Average weekly body weight for each line and sex was used to estimate model parameters using the ordinary least squares, weighted by the inverse variance of the body weight and weighted with a first-order autocorrelated error structure. Weighted models and weighted autocorrelated error models showed different parameter values when compared with the unweighted models, modifying the inflection point of the curve and according to the adjusted coefficient of determination, and the standard deviation of the residue and Akaike information criteria exhibited optimal adjustments. Among the models studied, the Richards and the Gompertz models had the best adjustments in all situations, with more realistic parameter estimates. However, the weighted Richards model, with or without ponderation with the autoregressive first order model AR (1), exhibited the best adjustments in females and males, respectively.

Three experiments were conducted to evaluate the use of corn oil in the diet of commercial layers as a method of increasing egg weight. In the first experiment, the performance of commercial layers receiving 6% added corn oil beginning at 18 to 30 wk at 2-wk intervals was evaluated. In the second experiment, comparisons were made between performance of young and old commercial layers when 6% corn oil was added to the diet. The third experiment was conducted to evaluate the effects upon commercial layers when 6% corn oil was added to diets varying in Trp content. In experiment 1, egg weights increased during the first 2 wk that corn oil was added to the diet. During this time, the intake of Trp was greater than or equal to the hen requirements. However, during the last 2 wk of the experiment, when Trp intakes were low, egg weights decreased when corn oil was added to the diet. In experiment 2, egg weights from young and old hens increased during the first 2 wk after corn oil was added to the diet. During the last 2 wk, egg weights from young hens decreased, whereas egg weights from old hens increased. In experiment 3, egg weight was not affected when the diet contained 0.166 or 0.176% Trp. However, egg weights significantly increased when corn oil was added to the diet containing 0.193% Trp. The data in these experiments indicate that the diet of a laying hen must contain a high level of Trp to get an increase in egg weight from the addition of corn oil to the diet. Also the need for other amino acids must be met. Therefore, the hen eats to meet her energy requirement for maximum egg production, and her amino acid intake determines the egg weight.