Were evaluated the effects of substituting limestone with quail eggshell powder on the zootechnical performance, egg quality, and economic efficiency of Japanese quails during peak egg production (11-20 weeks old). The experimental period was 63 days, divided into three 20-day periods. A completely randomized experimental design was used with five treatments (0, 25, 50, 75, and 100% substitution of limestone by eggshell powder), six repetitions, and seven birds per experimental unit, for a total of 210 quails. Feed intake, production of egg/bird/day, egg production per bird housed, marketable egg production, egg viability, feed conversion per egg mass, Seedor index, tibia calcium content, and percentage of calcium excreted were determined. The following variables for egg quality were analyzed: egg weight, specific weight, percentage of egg yolk, albumen and shell, and shell thickness. Economic efficiency was evaluated in fresh and industrialized eggs. Statistical analyses were performed using the SAS software, version 9.2 (2010). Substitution of limestone for eggshell powder had no significant effect on zootechnical performance, tibia calcium content, or egg quality. However, there were significant effects on the percentages of albumen and calcium excreted. The substitution of limestone by eggshell powder in quail feed resulted in higher economic efficiency indexes. These results indicate that the use of 100% eggshell powder in the feed of Japanese laying quails is viable.

Context: To obtain a good performance of the hens in the laying phase, adequate nutrition in the growth and pre-laying phase is necessary, especially for meeting amino acid requirements that are related to development of reproductive organs (ovary and oviduct). Aims: The objective of the present study was to predict the requirements for methionine (Met) plus cystine (Cys) from the growth of the body, feathers and reproductive organs of laying hens. Methods: The model estimates Met+Cys requirements as the relationship between the deposition of Met+Cys into three compartments (body, feathers, and reproductive organs) and their utilisation efficiency. The efficiency of utilisation was determined by a linear regression between Met+Cys deposition and intake for pullets aged 14–28, 56–70 and 98–112 days. Protein weight and deposition in the body and feathers were determined by the comparative slaughter method. The Gompertz function was used to model body, feathers, ovary, oviduct and liver weight against age. Key results: Our results showed that the inclusion of parameters descriptive of the growth of reproductive organs and the correction for feather losses in the model enabled Met+Cys requirements for growth in pre-laying trials to be predicted with a greater precision. Conclusions: The model developed in this study for determining the Met+Cys requirements for Dekalb White pullets could be extended, provided the necessary adjustments are made, to other amino acids, strains and species. Implications: Meeting Met+Cys requirements in the phase of maximum growth of the reproductive organs (weeks) contributes to the uniformity of the age when the pullets reach sexual maturity and, consequently, start the egg production.

To evaluate the response of broiler breeder hens submitted to different amino acid intakes of methionine+cystine, lysine, and threonine, and to determine the coefficients for egg output and body weight for maintenance. Three studies were performed using 160 broiler breeder hens housed individually in metabolic cages. A summit diet and a nitrogen-free diet were formulated. The levels ranged from 1.79 to 7.13, 2.49 to 8.3, and 2.04 to 6.79 g/kg of methionine+cystine, lysine, and threonine, respectively. The variables measured were feed intake, amino acid intake, rate of lay, egg weight, and egg output. The broken line model was used to evaluate the responses. It was verified that higher values of the rate of lay, egg weight, and egg output were observed for the higher concentrations of amino acids studied. A significant difference was observed for the variables rate of lay, egg weight, egg output, and body weight (p < 0.05) for the three amino acids evaluated. The amount of each amino acid required to produce one gram per egg was estimated at 12.4 mg, 14.5 mg, and 11.2 mg for methionine+cystine, lysine, and threonine, respectively. The values estimated by coefficient b that represent the amino acid for maintenance requirement were methionine+cystine, lysine, and threonine of 30.2, 32.2, and 42.4 mg/kg BW, respectively. The coefficients may be used to design additional models to study requirements nutrition in broiler breeders, allowing a better understanding of how these birds respond to different dietary amino acids.

Objective: Current quail production is configured as an economic activity in scale. Advancements in quail nutrition have been limited to areas such as breeding and, automation of facilities and ambience. The objective of this study was to evaluate the performance responses, liver and oviduct morphometry, and liver histology of Japanese laying quails subjected to different levels of nitrogen-corrected apparent metabolizable energy (MEn).Methods: A completely random design was used that consisted of nine levels of MEn, six replicates, and five hens per cage with a total of 270 quails. The experimental period lasted for 10 weeks. The variables of performance were subjected to analysis of variance and then regression analysis using the broken-line model. The morphometric and histological variables were subjected to multivariate exploratory techniques.Results: The MEn levels influenced the responses to zootechnical performance. The brokenline model estimated the maximum responses for feed intake, egg production, egg weight, and egg mass as 3,040, 2,820, 1,802, and 2,960 kcal of MEn per kg of diet, respectively. Multivariate analysis revealed that the occurrence of hepatic steatosis and increased levels of Kupffer cells were not related to MEn levels.Conclusion: The level of 2,960 kcal/kg of MEn meets performance variable requirements without compromising hepatic physiology.

The present research was defined to evaluate the residual feed intake (RFI) of white and brown groups of aged layers, between 85 to 90 weeks of age. A completely randomized design was used, with two treatments and 15 replicates, of one hen per replicate, for individual control. The treatment consisted of two genetic groups, brown and white (W-80), from Hy Line. Performance, egg quality, biometry visceral, body composition, energy partition, RFI, and residual metabolizable energy intake (RMEI) were evaluated. The results showed that egg weight was the main factor responsible for the difference between genotypes, affecting the production of the egg mass, yolk weight, and eggshell weight, as well as measures related to utilization efficiency (p < 0.05). The size of the uterus + vagina was larger for white layers (p < 0.05). The values obtained for RFI and RMEI were lower (p < 0.01) for white layers. While brown layers did not present hens with low RFI, 64.3% of the hens were classified as high RFI. The differences shown in this research between white and brown layers are smaller than in the past and show a tendency towards similarity; however, the economic impacts of the current differences are significant and must be considered.