Assessing Differences in the Quality Properties and Ultrastructure of Eggshell as Affected by Chicken Strain and Flock Age During Incubation Period

Three hundred hatching eggs from two layer breeder flocks (Hy-Line Brown and hy-Line W-36; 150 each) were obtained at three different periods of laying cycle (early, middle and late stages). The hatching eggs were randomly taken to assess the impact of chicken strain, age, and hatching time on some eggshell measurements and structures. Results indicate that egg weight, shell percentage and shell thickness were significantly affected by strain, breeder age, and incubation time. Increasing rate of calcium absorption and utilization by the embryos during the embryonic stage clearly reflects the decrease occurred in eggshell strength. The differences of eggshell breaking strength during incubation time periods were 0.41 and 0.55 kg/cm2, the differences due to the incubation time may be due to the higher demand for calcium utilization in the late incubation period (18 days), observed on the10th day of incubation. Brown eggs recorded significant higher calcium percentage in eggshell compared to the white ones. The brown breeder hens recorded significant higher total pores per egg compared to the white egg. Concerning eggshell ultrastructure, total thickness of the brown eggshell was significantly higher than those of the white eggshell by about 3.7%. All parameters, except for total thickness, were significantly affected by the interaction between strain and breeder age. Finally, we conclude that some traits including egg weight, shell percentage, shell thickness, calcium percentages in eggshell, and total pores per egg were significantly affected by strain, breeder age, and incubation time. Eggshell ultrastructure of brown egg was better compared to the white ones.(AU)

Qualidade de ovos comerciais oriundos de poedeiras tratadas com doxiciclina / Quality of commercial egg from laying hens treated with doxycycline / Calidad de huevos comerciales de gallinas ponedoras tratadas con doxiciclina

Doxiciclinaé um fármaco do grupo das tetraciclinas indicado para tratamento de diferentes doenças, em principal a coriza infecciosa. Entretanto, antimicrobianos do grupo das tetraciclinas tem capacidade de se ligarem e indisponibilizar minerais importantes para a formação dos ovos. O objetivo do projeto foi de avaliar a interferência da doxiciclina na qualidade de ovos comerciais. Realizou-se um estudo com 100 poedeiras Dekalb Brown®onde se avaliou a cor da gema, unidade Haugh, cor da casca, peso e espessura da casca. O delineamento adotado foi o inteiramente casualizadosem um esquema fatorial 2x2, resultando nos tratamentos: sem doxiciclina ao 5° dia; com doxiciclina ao 5° dia; sem doxiciclina ao 10° dia; com doxiciclina ao 10° dia. Coletou-se 4 ovos por repetição,totalizando 48 ovos analisado por tratamento em cada um dos períodos analisados. Não foram encontradas diferenças significativas entre os tratamentos para as variáveis de qualidade interna dos ovos (cor da gema e unidade Haugh). Para as variáveis de qualidade de casca, houve uma redução significativa dos níveis de amarelo com o uso de doxiciclina por 10 dias, além da redução do peso da casca e da espessura apical e equatorial da casca, principalmente no 10º dia e com o uso de doxiciclina. Conclui-se que o uso da doxiciclina não interfere na qualidade interna dos ovos, porém confere tonalidade acinzentada as cascas, e redução de peso e espessura das mesmas.(AU)

Doxycycline is a drug from the tetracycline group indicated for the treatment of different diseases, mainly infectious coryza. However, antimicrobials from the tetracycline group can bind and make minerals important for egg formation unavailable. The aim of this project is evaluated interference of doxycycline in quality of commercial egg. A study had carried out with 100 Dekalb Brown®laying hens where evaluated the yolk color, Haugh unit,color eggshell, weight and thickness eggshell. The delimitation had completely randomized in a 2x2 factorial scheme, resulting in treatments: without doxycycline at day 5; with doxycycline a day 5; without doxycycline at day 10; with doxycycline at day 10. Four eggs had gathered per replicate, totaling 48 eggs analyzed per treatment in each of the analyzed periods. No significant differences were found between treatments for internal egg quality variables (yolk color and Haugh unit). For the shell quality variables, there was a significant reduction in yellow levels with the use of doxycycline for 10 days, in addition to a reduction in shell weight and apical and equatorial shell thickness, mainly on the 10th day and with the use of doxycycline. It is concluded that the use of the doxycycline does not interfere in the internal quality of the eggs, but it gives a greyish tonality to the eggshells, and reduces their weight and thickness.(AU)

La doxiciclina es un fármaco del grupo de las tetraciclinas indicado para el tratamiento de diferentes enfermedades, principalmente el coriza infeccioso. Sin embargo, los antimicrobianos del grupo de las tetraciclinas tienen la capacidad de unirse y hacer que minerales importantes para la formación de huevos no estén disponibles. El objetivo de este proyecto es evaluar la interferencia de la doxiciclina en la calidad del huevo comercial. Se realizó un estudio con 100 gallinas ponedoras Dekalb Brown®donde se evaluó el color de la yema, unidad Haugh, color del cascarón, peso y grosor del cascarón. La delimitación tuvo completamente al azar en un esquema factorial 2x2,resultando tratamientos: sin doxiciclina en el día 5; con doxiciclina al día 5; sin doxiciclina el día 10; con doxiciclina el día 10. Se habían recolectado cuatro huevos por réplica, totalizando 48 huevos analizados por tratamiento en cada uno de los períodos analizados. No se encontraron diferencias significativas entre tratamientos para las variables de calidad interna del huevo (color de la yema y unidad Haugh). Para las variables de calidad de la cáscara, hubo una reducción significativa de los nivelesde amarillo con el uso de doxiciclina durante 10 días, además de una reducción del peso de la cáscara y del espesor apical y ecuatorial de la cáscara, principalmente al décimo día y con el uso de doxiciclina. Se concluye que el uso de la doxiciclina no interfiere en la calidad interna de los huevos, pero da una tonalidad grisácea a las cáscaras, y reduce su peso y grosor.(AU)

Nutritional Quality of Eggs of Amberlink and Hyline Layers Fed on Different Levels of Provitamin A-Biofortified Maize

The study was conducted to determine the interaction of types of maize (Provitamin A-biofortified maize (PABM) versus white maize) and strain of laying birds (Amberlink and Hyline) on nutritional quality of eggs. Twenty-one of each of Amberlink and Hyline laying hens were fed on three diets for 30 days. Birds were distributed in a 3 × 2 factorial arrangement constituting three diets (0, 50 or 100 % of PABM) and two strains (Amberlink & Hyline). There was a diet × strain interaction on egg shell weight, average daily feed intake, egg production, egg weight and egg shell thickness. Eggs produced by layers under 100 % PABM had lighter eggshell weight and lower eggshell percentage. In contrast, eggs produced by layers under 50 % PABM diet had signi-ficantly higher eggshell percentage, heavier egg shell weight and thicker eggshell. As the level of PABM increased, the yellow and red hue (Hunter a* and b* values) significantly increased while the lightness values (Hunter L* values) decreased. As the level of PABM in the ration increased, the vitamin A content of the egg yolk also significantly increased. Assimilation of vitamin A from feed to egg yolk in Amberlink and Hyline hens was similar. Hence, egg enrichment with vitamin A can be achieved by using PABM in layers ration. The use of high level of PABM had a negative effect on the eggshell quality traits.(AU)

Nutritional Quality of Eggs of Amberlink and Hyline Layers Fed on Different Levels of Provitamin A-Biofortified Maize

The study was conducted to determine the interaction of types of maize (Provitamin A-biofortified maize (PABM) versus white maize) and strain of laying birds (Amberlink and Hyline) on nutritional quality of eggs. Twenty-one of each of Amberlink and Hyline laying hens were fed on three diets for 30 days. Birds were distributed in a 3 × 2 factorial arrangement constituting three diets (0, 50 or 100 % of PABM) and two strains (Amberlink & Hyline). There was a diet × strain interaction on egg shell weight, average daily feed intake, egg production, egg weight and egg shell thickness. Eggs produced by layers under 100 % PABM had lighter eggshell weight and lower eggshell percentage. In contrast, eggs produced by layers under 50 % PABM diet had signi-ficantly higher eggshell percentage, heavier egg shell weight and thicker eggshell. As the level of PABM increased, the yellow and red hue (Hunter a* and b* values) significantly increased while the lightness values (Hunter L* values) decreased. As the level of PABM in the ration increased, the vitamin A content of the egg yolk also significantly increased. Assimilation of vitamin A from feed to egg yolk in Amberlink and Hyline hens was similar. Hence, egg enrichment with vitamin A can be achieved by using PABM in layers ration. The use of high level of PABM had a negative effect on the eggshell quality traits.

Qualidade de ovos e desempenho produtivo de poedeiras em segundo ciclo de postura alimentadas com microminerais quelatados a aminoácidos / Egg quality and productive performance of laying hens in second cycle of posture fed with aminoacid chelated trace minerals

The goal of this research was to evaluate egg quality and performance of laying hens at the second laying cycle, fed with minerals from an organic source. The control treatment consisted of basal diet with inorganic trace minerals, whereas the other treatments consisted of organic copper, iron, manganese, and zinc at levels of 100%, 90%, 80%, and 70%. Physical and chemical analyses were performed to evaluate egg quality. The average egg weight reduced in the test diet; however, egg mass, as well as the other performance variables evaluated, did not suffer influence of treatments. The percentage of egg protein decreased; however, mineral matter content and egg shell increased with the use of organic minerals, as well as an improvement in the egg quality parameters occurred. The supplementation with organic trace mineral source of the diet of laying hens did not compromise internal egg quality. The total replacement of inorganic sources for levels of organic minerals in the diet of birds provided maintenance on the performance and improved shell quality.

Objetivou-se com esta pesquisa avaliar o desempenho produtivo e a qualidade de ovos de poedeiras em segundo ciclo de postura alimentadas com microminerais de fonte orgânica. O tratamento controle foi composto por dieta basal e microminerais inorgânicos e os demais tratamentos consistiram da inclusão dos microminerais cobre, ferro, manganês e zinco orgânicos, em substituição total à fonte inorgânica, em níveis de 100%, 90%, 80% e 70%. Análises físicas e bromatológicas foram realizadas para avaliar a qualidade dos ovos. O peso médio dos ovos diminuiu nas dietas teste; no entanto, a massa de ovos bem como as demais variáveis de desempenho avaliadas não sofreram influencia dos tratamentos. O percentual de proteína do ovo diminuiu; entretanto, a matéria mineral do conteúdo interno e casca aumentaram com o uso de minerais orgânicos, assim como houve melhora nos parâmetros de qualidade da casca. A suplementação de microminerais de fonte orgânica a dieta das poedeiras não comprometeu a qualidade interna dos ovos. A total substituição da fonte inorgânica por níveis de minerais orgânicos nas dietas das aves proporcionou manutenção no desempenho zootécnico e melhorias na qualidade de casca.

Qualidade de ovos e desempenho produtivo de poedeiras em segundo ciclo de postura alimentadas com microminerais quelatados a aminoácidos / Egg quality and productive performance of laying hens in second cycle of posture fed with aminoacid chelated trace minerals

The goal of this research was to evaluate egg quality and performance of laying hens at the second laying cycle, fed with minerals from an organic source. The control treatment consisted of basal diet with inorganic trace minerals, whereas the other treatments consisted of organic copper, iron, manganese, and zinc at levels of 100%, 90%, 80%, and 70%. Physical and chemical analyses were performed to evaluate egg quality. The average egg weight reduced in the test diet; however, egg mass, as well as the other performance variables evaluated, did not suffer influence of treatments. The percentage of egg protein decreased; however, mineral matter content and egg shell increased with the use of organic minerals, as well as an improvement in the egg quality parameters occurred. The supplementation with organic trace mineral source of the diet of laying hens did not compromise internal egg quality. The total replacement of inorganic sources for levels of organic minerals in the diet of birds provided maintenance on the performance and improved shell quality.(AU)

Objetivou-se com esta pesquisa avaliar o desempenho produtivo e a qualidade de ovos de poedeiras em segundo ciclo de postura alimentadas com microminerais de fonte orgânica. O tratamento controle foi composto por dieta basal e microminerais inorgânicos e os demais tratamentos consistiram da inclusão dos microminerais cobre, ferro, manganês e zinco orgânicos, em substituição total à fonte inorgânica, em níveis de 100%, 90%, 80% e 70%. Análises físicas e bromatológicas foram realizadas para avaliar a qualidade dos ovos. O peso médio dos ovos diminuiu nas dietas teste; no entanto, a massa de ovos bem como as demais variáveis de desempenho avaliadas não sofreram influencia dos tratamentos. O percentual de proteína do ovo diminuiu; entretanto, a matéria mineral do conteúdo interno e casca aumentaram com o uso de minerais orgânicos, assim como houve melhora nos parâmetros de qualidade da casca. A suplementação de microminerais de fonte orgânica a dieta das poedeiras não comprometeu a qualidade interna dos ovos. A total substituição da fonte inorgânica por níveis de minerais orgânicos nas dietas das aves proporcionou manutenção no desempenho zootécnico e melhorias na qualidade de casca. (AU)

QUALIDADE DE OVOS E DESEMPENHO PRODUTIVO DE POEDEIRAS EM SEGUNDO CICLO DE POSTURA ALIMENTADAS COM MICROMINERAIS QUELATADOS A AMINOÁCIDOS

Abstract The goal of this research was to evaluate egg quality and performance of laying hens at the second laying cycle, fed with minerals from an organic source. The control treatment consisted of basal diet with inorganic trace minerals, whereas the other treatments consisted of organic copper, iron, manganese, and zinc at levels of 100%, 90%, 80%, and 70%. Physical and chemical analyses were performed to evaluate egg quality. The average egg weight reduced in the test diet; however, egg mass, as well as the other performance variables evaluated, did not suffer influence of treatments. The percentage of egg protein decreased; however, mineral matter content and egg shell increased with the use of organic minerals, as well as an improvement in the egg quality parameters occurred. The supplementation with organic trace mineral source of the diet of laying hens did not compromise internal egg quality. The total replacement of inorganic sources for levels of organic minerals in the diet of birds provided maintenance on the performance and improved shell quality.

Resumo Objetivou-se com esta pesquisa avaliar o desempenho produtivo e a qualidade de ovos de poedeiras em segundo ciclo de postura alimentadas com microminerais de fonte orgânica. O tratamento controle foi composto por dieta basal e microminerais inorgânicos e os demais tratamentos consistiram da inclusão dos microminerais cobre, ferro, manganês e zinco orgânicos, em substituição total à fonte inorgânica, em níveis de 100%, 90%, 80% e 70%. Análises físicas e bromatológicas foram realizadas para avaliar a qualidade dos ovos. O peso médio dos ovos diminuiu nas dietas teste; no entanto, a massa de ovos bem como as demais variáveis de desempenho avaliadas não sofreram influencia dos tratamentos. O percentual de proteína do ovo diminuiu; entretanto, a matéria mineral do conteúdo interno e casca aumentaram com o uso de minerais orgânicos, assim como houve melhora nos parâmetros de qualidade da casca. A suplementação de microminerais de fonte orgânica a dieta das poedeiras não comprometeu a qualidade interna dos ovos. A total substituição da fonte inorgânica por níveis de minerais orgânicos nas dietas das aves proporcionou manutenção no desempenho zootécnico e melhorias na qualidade de casca.

Granulometria do calcário calcítico na dieta de codornas japonesas após o pico de postura

A utilização de estratégias nutricionais dentro da coturnicultura que preservem a qualidade da casca dos ovos e dos ossos da ave são importantes para produção de maior número de ovos comercializáveis, que refletem diretamente na rentabilidade do sistema de produção. Conforme a ave envelhece o peso do ovo aumenta e a capacidade da ave de aproveitamento do cálcio é reduzida, refletindo em pior qualidade de casca e menor reserva de cálcio no osso. Objetivou-se com o presente trabalho avaliar a influência da granulometria do calcário calcítico em parâmetros de qualidade óssea, qualidade dos ovos e desempenho de codornas japonesas (Coturnix coturnix japonica) após o pico de postura. Foram utilizadas 240 codornas japonesas, com idade entre 214 a 277 dias de vida, distribuídas em delineamento inteiramente casualizado, sendo cinco tratamentos e seis repetições, com oito codornas por unidade experimental e duração experimental de 63 dias. Duas diferentes granulometrias foram utilizadas para compor os tratamentos, sendo considerada granulometria grossa o calcário calcítico apresentando Diâmetro Geométrico Médio (DGM)= 1,14mm e fina DGM= 0,117mm. Os tratamentos utilizados foram: T1 ração com 100% de calcário calcítico de granulometria grossa; T2 - ração com 70% de calcário de granulometria grossa e 30% fina; T3 - ração com 50% de calcário de granulometria grossa e 50% fina; T4 ração com 30% de calcário de granulometria grossa e 70% fina; T5 ração com 100% de calcário de granulometria fina. A substituição do calcário calcítico de granulometria mais grossa pelo calcário calcítico de granulometria mais fina não infuencia os parâmetros de desempenho, qualidade dos ovos e qualidade óssea de codornas japonesas após o pico de postura, com idade de 214 a 277 dias de idade.

The use of nutritional strategies on quail production that preserves eggshell and bone quality are important to produce a great number of marketable eggs, which directly reflects on profitability of the production system. As quail ages, egg weight increases and the ability to use calcium is reduced, reflecting in worse shell quality and less calcium reserve in bone. The objective of this study was to evaluate the influence of limestone particle size on bone quality, egg quality and performance parameters of Japanese quails (Coturnix coturnix japonica) after production peak. 240 Japanese quails were used, aged 214 to 277 days old, distributed in a completely randomized design, with five treatments and six replications, with eight quails per experimental unit and an experimental period of 63 days. Two limestone particle sizes were used to formulate diets: coarse limestone with average geometric diameter (AGD) = 1.14mm and limestone considered fine AGD = 0.117mm. The treatments used were: T1 - diet with 100% coarse limestone; T2 70% coarse limestone and 30% fine limestone; T3 - 50% coarse limestone and 50% fine; T4 - 30% coarse limestone and 70% fine; T5 diet with 100% fine limestone. The replacement of the coarse limestone by fine limestone does not influence performance, egg quality and bone quality of Japanese quails after production peak, aged 214 to 277 days old.

Efeitos da enrofloxacina ,da sulfaquinoxalina e da nicarbazina na dieta de galinhas de postura sobre a qualidade da casca do ovo

A qualidade da casca dos ovos de galinhas poedeiras é definida pelo grau de higiene, integridade, resistência e deformações. Alguns fatores nutricionais, de manejo e ambientais podem causar a perda da qualidade da casca de ovos e entre eles estão a utilização de alguns medicamentos durante a fase de postura das aves. Com o objetivo de avaliar a qualidade da casca dos ovos de galinhas poedeiras tratadas com os antimicrobianos sulfaquinoxalina e enrofloxacina e com o anticoccidiano nicarbazina foram utilizadas 200 galinhas de postura (50 por tratamento), da linhagem Lohmann Brown, com 60 semanas de idade. Os tratamentos definidos de acordo com o antimicrobiano ou o anticoccidiano fornecido às aves via ração, foram os seguintes: A) aves que receberam ração sem medicamento do primeiro dia até o 15º dia experimental (controle); B) aves que receberam sulfaquinoxalina na concentração de 250 mg.Kg-1 de ração do primeiro dia até o terceiro dia do experimento; C) aves que receberam enrofloxacina na concentração de 125 mg.Kg- 1 de ração do primeiro até o quinto dia e; D) aves que receberam nicarbazina na ração em subdosagem de 40 mg.Kg-1 de ração (com a intenção de simular a contaminação acidental da ração) do primeiro até o quinto dia. Após o período de tratamento, as aves dos tratamentos B, C e D, receberam ração sem medicamento até o 15º dia experimental. Foram coletados os ovos dos dias quatro, cinco, seis, sete, 11 e 15 do período experimental e foram realizadas as avaliações de peso específico do ovo, peso, porcentagem, resistência, espessura, porosidade, coloração e teor de cálcio da casca. Os resultados observados demonstraram diminuição das porcentagens e aumentos das porosidades das cascas dos ovos tratados com sulfaquinoxalina, o que resultou em redução do peso específico dos ovos; os ovos provenientes de galinhas tratadas com enrofloxacina apresentaram cascas com deformações e perda de coloração e; o uso acidental de nicarbazina na ração de galinhas poedeiras provocou a despigmentação das cascas dos ovos. Foi concluído que o tratamento das aves com sulfaquinoxalina, enrofloxacina e nicarbazina durante o período de postura resultou em piora da qualidade da casca dos ovos

The eggshell quality of laying hens is defined by the degree of hygiene, integrity, strength and deformation. Some nutritional, management and environmental factors can cause loss of eggshell quality and among them are the use of some medications during the laying phase of the hens. With the aim of evaluating the quality of laying hens eggshell treated with antimicrobial sulfaquinoxaline and enrofloxacin and with coccidiostatic nicarbazin, 200 Lohmann brown laying hens (50 per treatment) with 60 weeks old were used. The treatments defined according to the antimicrobial or coccidiostatic provided to the hens via feed were as following: A) hens that received feed without medication from the first day to the 15th experimental day (control); B) hens that received sulfaquinoxaline at the concentration of 250 mg.kg-1 of feed from the first day to the 3rd day of the experiment; C) hens that received enrofloxacin at the concentration of 125 mg.kg -1 of feed from the first to the 5th day and; D) hens that received nicarbazin in the feed underdosage 40 mg.kg-1 of feed (with the intention of simulating the accidental contamination of the feed) from the first to the 5th day. After the treatment period, the hens of treatments B, C and D received feed without medication until the 15th experimental day. Eggs were collected from days 4th, 5th, 6th, 7th, 11th and 15th of the experimental period for the determinations of specific weight of the eggs and weight, percentage, resistance, thickness, porosity, coloration and calcium content of the eggshell. The observed results demonstrated a decrease in the percentages and increases in the porosities of the eggshells treated with sulfaquinoxaline, which resulted in a reduction in specific weight of the eggs. Eggs from chickens treated with enrofloxacin showed deformed eggshells and loss of color. The accidental use of nicarbazin in the laying hens feeding led to the depigmentation of eggshells. It was concluded that the treatment of hens with sulfaquinoxaline, enrofloxacin and nicarbazin during the laying period resulted in worsening of quality of the eggshells.

PRODUÇÃO E QUALIDADE DE OVOS DE GALINHAS POEDEIRAS COM RAÇÕES DE DIFERENTES RELAÇÕES DE GRANULOMETRIAS DE CALCÁRIO

A recomendação de calcário pedrisco na alimentação de galinhas poedeiras visa melhorar a biodisponibilidade do cálcio. Esta prática de manejo nutricional tem como objetivo uma casca de melhor qualidade, considerando que as partículas maiores de calcário influenciam o tempo de residência do alimento ao longo do trato gastrintestinal proporcionando uma melhora na taxa de solubilidade in vivo do cálcio. Esta tese está subdividida em três capítulos. O primeiro capítulo aborda as considerações gerais do tema proposto. No segundo capítulo objetivou-se avaliar o uso de diferentes níveis de inclusão de calcário pedrisco na dieta de galinhas poedeiras. Os tratamentos foram: T1: 100% calcário fino (FL- 0,103 mm); T2: 50% FL e 50% pedrisco (CL- 2,867 mm); T3: 40% FL e 60% CL; T4: 30% FL e 70% CL; T5: 20% FL e 80% CL. Foi avaliado desempenho zootécnico, qualidade interna e da casca do ovo e a digestibilidade dos minerais. As diferentes relações granulométricas de calcário avaliadas não tiveram efeito nas variáveis taxa de postura, peso do ovo, conversão alimentar, índice de albúmen e Unidade Haugh. Foi observada maior percentagem de matéria mineral na casca dos ovos nos tratamentos 60%, 70% e 80% de inclusão do calcário pedrisco, não demonstrando melhoria nas outras variáveis de qualidade da casca. A partir desse estudo não foi possível definir uma relação ótima da inclusão do calcário pedrisco nas dietas de galinhas poedeiras comerciais em produção. No capítulo III, objetivou-se comparar diferentes granulometrias de pedrisco de calcário na ração de galinhas poedeiras avaliando a qualidade das cascas de ovos, além da qualidade interna e produtividade. Os tratamentos foram T1: 100% calcário fino (FL- 0,103 mm); T2: 50% FL e 50% calcário médio 1 (ML-1 0,555 mm); T2: 50% FL e 50% calcário médio 2 (1,836 mm); T4: 50% FL e 50% calcário pedrisco (CL- 2,867 mm). As diferentes relações granulométricas e tamanhos de partículas do calcário não determinaram diferenças nas variáveis de qualidade da casca ovo. Foram observadas diferenças na quantidade de minerais retidos no trato gastrintestinal das aves sendo a associação de calcário fino e o calcário médio 1 que resulta nas maiores taxas de retenção da matéria mineral, cálcio e fósforo. As diferentes inclusões de calcário pedrisco podem ter modificado a capacidade de absorção dos minerais no organismo da ave, mas a partir dos resultados encontrados nesse estudo não é possível afirmar uma relação direta com o tamanho de partículas. No geral, a partir desse estudo não foi possível definir uma relação ideal de granulometria do calcário nas dietas de galinhas poedeiras.

ABSTRACT The recommendation of coarse limestone in feeding commercial hens aims to improve the bioavailability of calcium. This nutritional management practice aims to improve the quality of the eggshell, considering that the larger particles of limestone influence the residence time of the food along the gastrointestinal tract, providing an improvement in the in vivo solubility rate of calcium. This thesis is subdivided into three chapters. The first chapter approaches general considerations about the theme. In the second chapter, the objective was to evaluate the use of different levels of coarse limestone in the laying hens diet. The treatments were: T1: 100% fine limestone (FL- 0,103 mm); T2: 50% FL and 50% coarse limestone (CL- 2,867 mm); T3: 40% FL and 60% CL; T4: 30% FL and 70% CL; T5: 20% FL and 80% CL. It was evaluated performance, internal quality, eggshell quality and the digestibility of minerals. The different granulometrics of limestone evaluated had no effect on the studied variables of performance and internal egg quality. It was observed a higher percentage of mineral matter in the eggshell in the treatments 60%, 70% and 50% of coarse limestone, showing no improvement in the other variables of eggshell quality. From this study it was not possible to define an optimal relation of the inclusion of limestone in the diets of commercial laying hens in production. In chapter III, the objective of this study was to compare different limestone granulometry in laying hens ration evaluating eggshell quality, as well as internal and productive quality. The treatments were T1: 100% fine limestone (FL-0.103 mm); T2: 50% FL and 50% medium limestone 1 (ML-1 0.555 mm); T3: 50% FL and 50% medium limestone 2 (ML-2 1,836 mm); T4: 50% FL and 50% coarse limestone (CL- 2.877 mm). Under these experimental conditions, the different granulometry and particle size of the limestone did not determine differences in eggshell quality variables. Differences were observed in the amount of minerals retained in the gastrointestinal tract of laying, with the association of fine limestone and average limestone 1, which results in the higher retention rates of mineral matter, calcium and phosphorus. The different inclusions of coarse limestone may have altered the absorption capacity of the minerals in the laying's organism, but from the results found in this study it is not possible to assert a direct relation with the particle size. In general, from this study it was not possible to define an ideal relation of limestone granulometry in laying hens diets.

CÁLCIO E FÓSFORO DISPONÍVEL NA DIETA SOBRE O DESEMPENHO PRODUTIVO, QUALIDADE ÓSSEA E DA CASCA DE OVOS DE GALINHAS POEDEIRAS POR MEIO DE META-ANÁLISES.

Dois estudos foram conduzidos para avaliar os efeitos dos níveis de cálcio e fósforo disponível na dieta sobre o consumo de ração, produção de ovos, peso dos ovos, massa de ovos, conversão alimentar, porcentagem de casca do ovo, espessura da casca, gravidade específica e porcentagem de cinzas na tíbia de galinhas poedeiras usando a abordagem metaanalítica. Foram utilizados modelos mistos para avaliação dos efeitos lineares e quadráticos dos níveis de cálcio e fósforo disponível sobre as variáveis respostas. Na meta-análise que avaliou o efeito do cálcio o banco de dados foi composto por 37 ensaios, extraídos de uma tese e 22 artigos publicados de 1993 a 2015. O consumo de ração reduziu de forma linear e a porcentagem de cinzas na tíbia aumentou de forma linear em função do incremento dos níveis de cálcio na dieta, as estimativas dos coeficientes lineares do cálcio foram diferentes de zero com valores de P iguais a 0,0007 e 0,0215, respectivamente. A produção de ovos (P = 0,0266), massa de ovos (P = 0,0143), conversão alimentar (P = 0,0142), porcentagem de casca do ovo (P 0,0001), espessura da casca (P = 0,0385) e gravidade específica (P 0,0001) foram influenciadas de forma quadrática pelo incremento dos níveis de cálcio da dieta. Na meta-análise que avaliou o efeito de fósforo disponível o banco de dados foi composto por 30 ensaios, extraídos de uma dissertação e 17 artigos publicados de 1993 a 2017. As variáveis de desempenho foram influenciadas pelo incremento dos níveis de fósforo disponível na dieta de forma linear (i.e., peso dos ovos; P = 0,0308) e quadrática (i.e., consumo de ração; P = 0,0040, produção de ovos; P = 0,0007 e massa de ovos; P = 0,0004), já que as estimativas dos coeficientes lineares e quadráticos do fósforo disponível foram diferentes de zero. No entanto, as variáveis de qualidade óssea e da casca de ovos de galinhas poedeiras não foram influenciadas pelos níveis de fósforo disponível. Dietas que contém níveis de cálcio compreendidos em 39,22 e 44,45 g/kg promovem a máxima resposta para desempenho e qualidade da casca dos ovos em galinhas poedeiras. Assim como, dietas que contém o nível de fósforo disponível de 3,82 g/kg promove a máxima resposta para desempenho sem comprometer a qualidade da casca de ovos em galinhas poedeiras.

Two studies were conducted to evaluate the effects of calcium and available phosphorus levels in the diet on feed intake, egg production, egg weight, egg mass, conversion feed ratio, eggshell percentage, eggshell thickness, specific gravity and ash percentage of the tibia of laying hens using a meta-analytic approach. Mixed models were used to evaluate the linear and quadratic effects of calcium and available phosphorus levels on the response. In the metaanalysis that evaluated the effect of calcium the database consisted of 37 trials and 22 scientific articles published from 1993 to 2015. Feed intake decreased linearly and the percentage of ash in the tibia increased linearly as a function of the increase of calcium levels in the diet, estimates of linear calcium coefficients were different from zero with P values equal to 0.0007 and 0.0215, respectively. Egg production (P = 0.0266), egg mass (P = 0.0143), feed conversion (P = 0.0142), egg shell percentage (P 0.0001), shell thickness P = .0385) and specific gravity (P 0.0001) were influenced in a quadratic form by the increment of calcium levels of the diet. The meta-analysis evaluating the effect of phosphorus available the database consisted of 30 trials, extracted from a dissertation and 17 articles published from 1993 to 2017. The performance variables were influenced by the increase in dietary phosphorus levels in a linear (ie, egg weight, P = 0.0308) and quadratic form (ie, feed intake, P = 0.0040, egg production; P = 0.0007 and egg mass, P = 0.0004), since the estimates of the linear and quadratic coefficients of the available phosphorus were different from zero. However, the bone quality and egg shell variables of laying hens were not influenced by the levels of available phosphorus. Diets containing calcium levels of 39.22 and 44.45 g/kg promote the maximum performance response and eggshell quality in laying hens, respectively. As well as, diets containing the Pd level of 3.82 g/kg promote maximum performance response without compromising eggshell quality in laying hens.

Calcium in pre-laying and laying rations on the performance and quality of laying hens eggshell / Cálcio nas rações de pré-postura e postura sobre o desempenho e qualidade de casca dos ovos de poedeiras comerciais

The experiment evaluated the effect of different calcium (Ca) levels in pre-laying and laying diets on the performance and egg quality of laying hens. Two hundred and fifty-six 16-week-old Brown Hisex pullets were housed in a conventional shed. The experiment had a completely randomized design with 4 x 2 factorial arrangement (four calcium levels - 0.8, 1.3, 1.8 and 2.3% in pre-laying phase; two calcium levels - 2.5 and 3.5% in laying phase), totaling eight treatments with four repetitions of eight birds per experimental unit. The experimentstarted with 16-week-old hens receiving pre-laying diets provided until they were 18 weeks old. At this period, the laying diets started. Four 28-day cycles were evaluated for the following variables: production and egg weight, feed intake, feed conversion, mass of eggs and eggshell quality. Results show that a good performance was obtained with 0.8% calcium level in the pre-laying phase, whereas in the laying phase the 3.5% calcium level provided greater weight egg and better eggshell quality.

O ensaio experimental objetivou avaliação do efeito de diferentes níveis de cálcio (Ca) nas rações de pré-postura e postura sobre o desempenho e qualidade dos ovos de poedeiras comerciais. Foram alojadas 256 frangas da linhagem Hisex Brown com 16 semanas de idade em galpão convencional de postura. O delineamento experimental foi inteiramente casualizado em arranjo fatorial 4 x 2 (4 níveis de cálcio - 0,8; 1,3; 1,8 e 2,3% na pré-postura e 2 níveis de cálcio - 2,5 e 3,5% na postura), totalizando oito tratamentos com quatro repetições de oito aves por unidade experimental. Iniciou-se com a ração de pré-postura às 16 semanas de idade das aves, sendo que a mesma foi fornecida até as aves atingiram 18 semanas de idade, quando então, iniciou-se com a ração de postura. Foram avaliadas durante quatro ciclos de 28 dias as seguintes variáveis: produção e peso dos ovos,consumo de ração, conversão alimentar, massa de ovos e qualidade da casca dos ovos. Através dos resultados obtidos pode-se concluir que um bom desempenho foi obtido com 0,8% de cálcio na fase de pré-postura. Na fase de postura o nível de 3,5% de cálcio promoveu maior peso de ovo e melhor qualidade de casca.

Calcium in pre-laying and laying rations on the performance and quality of laying hens eggshell / Cálcio nas rações de pré-postura e postura sobre o desempenho e qualidade de casca dos ovos de poedeiras comerciais

The experiment evaluated the effect of different calcium (Ca) levels in pre-laying and laying diets on the performance and egg quality of laying hens. Two hundred and fifty-six 16-week-old Brown Hisex pullets were housed in a conventional shed. The experiment had a completely randomized design with 4 x 2 factorial arrangement (four calcium levels - 0.8, 1.3, 1.8 and 2.3% in pre-laying phase; two calcium levels - 2.5 and 3.5% in laying phase), totaling eight treatments with four repetitions of eight birds per experimental unit. The experimentstarted with 16-week-old hens receiving pre-laying diets provided until they were 18 weeks old. At this period, the laying diets started. Four 28-day cycles were evaluated for the following variables: production and egg weight, feed intake, feed conversion, mass of eggs and eggshell quality. Results show that a good performance was obtained with 0.8% calcium level in the pre-laying phase, whereas in the laying phase the 3.5% calcium level provided greater weight egg and better eggshell quality.(AU)  

O ensaio experimental objetivou avaliação do efeito de diferentes níveis de cálcio (Ca) nas rações de pré-postura e postura sobre o desempenho e qualidade dos ovos de poedeiras comerciais. Foram alojadas 256 frangas da linhagem Hisex Brown com 16 semanas de idade em galpão convencional de postura. O delineamento experimental foi inteiramente casualizado em arranjo fatorial 4 x 2 (4 níveis de cálcio - 0,8; 1,3; 1,8 e 2,3% na pré-postura e 2 níveis de cálcio - 2,5 e 3,5% na postura), totalizando oito tratamentos com quatro repetições de oito aves por unidade experimental. Iniciou-se com a ração de pré-postura às 16 semanas de idade das aves, sendo que a mesma foi fornecida até as aves atingiram 18 semanas de idade, quando então, iniciou-se com a ração de postura. Foram avaliadas durante quatro ciclos de 28 dias as seguintes variáveis: produção e peso dos ovos,consumo de ração, conversão alimentar, massa de ovos e qualidade da casca dos ovos. Através dos resultados obtidos pode-se concluir que um bom desempenho foi obtido com 0,8% de cálcio na fase de pré-postura. Na fase de postura o nível de 3,5% de cálcio promoveu maior peso de ovo e melhor qualidade de casca.(AU)

SUPLEMENTAÇÃO DE MINERAIS COMPLEXADOS A AMINOÁCIDOS EM DIETAS DE GALINHAS POEDEIRAS DE 78 A 98 SEMANAS DE IDADE

Fontes de microminerais complexados a moléculas orgânicas têm melhorado a absorção e o desempenho pelas aves. A pesquisa foi conduzida para avaliar diferentes fontes e os efeitos da suplementação dos microminerais Zinco (Zn), Manganês (Mn), Cobre (Cu), Ferro (Fe) e Selênio (Se) quelatados, associados com fontes inorgânicas sobre o desempenho e qualidade interna e externa dos ovos de galinhas poedeiras. A pesquisa foi desenvolvida nas instalações de Pesquisa da Estação Experimental de Pequenos Animais de Carpina (EEPAC), localizada no município de Carpina-PE, Brasil. A pesquisa foi dividida em dois experimentos em que foram utilizadas novecentas galinhas poedeiras (Lohmann White) durante o período de 78 a 98 semanas de idade. No primeiro experimento as aves foram distribuídas de acordo com delineamento experimental inteiramente casualizado com quatro tratamentos com dez aves por repetição. Os tratamentos consistiram em quatro dietas, com a substituição total da fonte mineral inorgânica por fonte de microminerais complexado a aminoácidos (MCAA) com redução do níveis de suplementação em 30, 50 e 60%, respectivamente, sendo: T1 Dieta-controle com apenas fontes de minerais inorgânicos; T2: Dieta suplementada com MCAA e redução de 30% nos níveis dos minerais; T3: Dieta suplementada com MCAA e redução de 50% nos níveis dos minerais e T4: Dieta suplementada com MCAA e redução de 60% nos níveis dos minerais. Os dados foram submetidos à análise de variância e ao teste Tukey (P<0,05). A suplementação do mineral MCAA aumentou significativamente a produção, peso e massa de ovo, tendo o T4 com redução de 60% nos níveis dos minerais os melhores resultados quando comparado às demais dietas, sendo que a dieta-controle apresentou as menores médias. As aves alimentadas com MCAA apresentaram melhor conversão por massa e por dúzia de ovos; a dieta T4 com redução de 60% apresentou melhor conversão por massa e por dúzia de ovos quando comparada aos demais tratamentos. Em relação aos parâmetros de qualidade dos ovos, observou-se diferença significativa para espessura da casca, tendo a dieta T4 com redução de 60% CMAA apresentado o melhor resultado em relação à dieta-controle e as dietas com redução de 30 e 50% do MCAA. No segundo experimento, as aves foram distribuídas em um delineamento inteiramente casualizado com cinco tratamentos, dez repetições com dez aves por repetição, onde foram testadas diferentes fontes de microminerais complexados a aminoácidos. Os tratamentos foram um arranjo fatorial 2 x 2 + 1 controle inorgânico: os fatores foram duas fontes de Zn, Mn e Cu (Mineral complexado a aminoácidos (MCAA) e Mineral Glicinato (MG) em dois níveis baixos (20, 20 e 3,5 ppm de Zn, Mn e Cu, respectivamente), e alta (40, 40 e 7 ppm de Zn, Mn e Cu, respectivamente). A dieta-controle inorgânica (Sulfatos) continha Zn, Mn e Cu nos níveis elevados (40, 40 e 7 ppm, respectivamente). Ferro, Se e I foram suplementados com fontes inorgânicas nos mesmos níveis em todas as dietas. Os dados foram submetidos à análise de variância, com médias comparadas por contrastes ortogonais (fonte mineral, nível, fonte x nível e fonte) quando P <0,05. As galinhas poedeiras alimentadas com MCAA apresentaram melhor (P <0,05) produção de ovos (%), massa de ovos (g/ave/dia), conversão alimentar (g: massa g: dz de ovos), altura do albúmen (mm), unidades Haugh e espessura da casca do ovo em comparação com poedeiras alimentadas com dietas contendo sulfatos e MG, sendo que o sulfato apresentou melhor resultado para altura de albúmen e unidades Haugh quando comparado ao tratamento com MG. Esses dados mostram diferenças claras entre as fontes de microminerais, tendo a fonte MCAA com resultado superior às fontes de MG e sulfatos, e este último melhor que o glicinato para galinhas poedeiras.

Sources of microminerals complexed to organic molecules have improved their absorption and metabolism by birds. The research was conducted to evaluate the effects of the supplementation of the microminerals Zinc, Manganese (Mn), Copper (Cu) Iron (Fe) and Selenium (Se) in organic form associated with inorganic sources on internal and external performance and quality of laying hens' eggs. The research was carried out in the research facilities of the Experimental Station of Small Carpathian Animals (EEPAC) located in the municipality of Carpina. Nine hundred laying hens (Lohmann White) were used during the 78-98 week period, the research was divided into two experiments. In the first experiment the birds were distributed according to a completely randomized experimental design with four treatments and ten replicates of ten birds per experimental unit. The treatments consisted of four diets, with total substitution of the inorganic mineral source by amino-acid complexed with amino acids (CMAA), with reduction of supplementation levels in 30, 50 and 60%, respectively: T1-Control diet with only sources of inorganic minerals, and T2; T3 and T4 Diet 100% (CMAA). Data were submitted to analysis of variance and Tukey test (P <0.05). The supplementation of the CMAA mineral significantly increased the egg production, weight and mass as the quantity of the CMAA mineral was reduced, the treatment with 60% reduction being the best results when compared to the other diets, whereas the control diet showed the lowest means. MAC-fed birds presented better conversion by mass and dozen eggs; the diet with 60% reduction presented better conversion by mass and dozen eggs when compared to the other treatments. Regarding the parameters collected from the eggs, a significant difference was observed for the thickness of the bark, and the diet with a 60% CMAA reduction presented the best result in relation to the control diet and the diets with a CMAA reduction of 30 and 50%. In the second experiment the birds were distributed in a completely randomized design with five treatments, ten replicates per treatment and ten birds per replicate. The treatments were a 2 x 2 + 1 factorial arrangement plus an inorganic control: the factors were two sources of Zn, Mn and Cu (CMAA or GM) at two levels (low, 20, 20 and 3.5 ppm of Zn, Mn and Cu); respectively, and high, 40, 40 and 7 ppm of Zn, Mn and Cu, respectively). The inorganic control diet contained Zn, Mn and Cu at high levels (40, 40 and 7 ppm, respectively). Iron, Se and I were supplemented with inorganic sources at the same levels in all diets. The data were submitted to analysis of variance, with averages compared by orthogonal contrasts (mineral source, level, source x level and source) when P <0.05. CMAA-fed laying hens presented better egg production (%), egg mass (g / bird / day), feed conversion per mass and per dozen eggs (g: dz; g: egg mass), bark thickness of egg (mm), height of albumen), and Haugh units in comparison to laying hens fed GM-containing diets. These data show clear differences in micromineral sources with amino acid complexes resulting in superior performance compared to glycinate sources for laying hens. Supplementation of laying diets with MAC and CMAA at the production stage improved performance and egg quality parameters.

Avaliação da qualidade da casca dos ovos provenientes de matrizes pesadas com diferentes idades / Evaluation of eggshell quality from broiler breeder hens with different ages

Foi realizado um estudo sobre qualidade da casca dos ovos incubáveis provenientes de matrizes pesadas com diferentes idades, por meio da avaliação da relação entre peso da casca e peso do ovo e análises de peso específico, espessura, porosidade, resistência e microscopia eletrônica. Os dois tratamentos foram definidos pela idade da matriz, sendo considerados ovos de matrizes novas - 33 semanas - e de matrizes velhas - 63 semanas. Os ovos de matrizes com 33 semanas foram mais leves, e o número de poros por cm² foi menor que o de ovos das aves mais velhas. Ovos de aves com 63 semanas apresentaram menor percentual de casca em relação ao peso do ovo, menor peso específico e menores resistência e espessura da casca. A proporção das membranas da casca em relação à sua espessura total foi maior nas matrizes mais novas. Concluiu-se que ovos de matrizes velhas têm qualidade de casca inferior aos ovos das matrizes novas e que as membranas da casca nos ovos de matrizes novas desempenham papel relevante em sua estrutura.(AU)

We conducted a study on eggshell quality from Cobb® broiler breeders at different ages by assessing the relationship between eggshell weight and egg weight and analysis of specific weight, thickness, porosity, strength and electron microscopy. Both treatments were defined by broiler breeder age, considering eggs from young breeders (33 weeks) and eggs from old breeders (63 weeks). It was observed that eggs from breeders at 33 weeks have lower weight and number of pores per cm² compared with eggs from older birds. 63 weeks broiler breeders had lower percentage of eggshell in relation to egg weight, lower specific weight, strength and thickness, when compared with eggs from young breeders. The proportion of shell membranes in relation to its total thickness was significantly higher in young breeders. It was concluded that eggs from older broiler breeders have lower eggshell quality than the young breeders. The shell membranes in young breeder's eggs play a significant role in its structure, making it necessary to focus on this layer in future studies on eggshell quality and their relationship between breeder age and incubation yield.(AU)

Effects of calcium levels and limestone particle size on the egg quality of semi-heavy layers in their second production cycle

A 112-day trial was carried out to evaluate the effect of dietary calcium level and limestone particle size on the egg quality of 288 Hy-Line Brown semi-heavy layers, with 83 weeks of age at the beginning of the experiment. A completely randomized experimental design was applied in a 2x3 factorial arrangement, with two dietary calcium levels (3.5 and 4.0%) e three limestone particle size compositions (100% fine limestone (FL), with 0.185mm; 30% coarse limestone (CL), with 2.83mm, + 70% FL, with 0.185mm; and 50% CL, with 2.83mm, + 50% FL, with 0.185mm), with six replicates of eight birds each. Mean geometric diameter and in-vitro solubility of the limestone sources were, respectively, 0.185mm and 18.7% for the fine limestone, and 2.83mm and 10.5% for the coarse limestone. At the end of each 28-day period, 72 eggs per treatment were used to determine egg specific gravity, yolk percentage, albumen percentage, eggshell percentage, yolk index, Haugh units, eggshell thickness, and eggshell breaking strength. There was no influence of the treatments on the evaluated parameters. It was concluded that feeding the level of 3.5% calcium usually recommended for layers in their first laying cycle, and the substitution of up to 50% fine limestone by coarse limestone in the feed of semi-heavy commercial Hy-Line Brown layers in their second laying cycle can be applied with no impairment of egg quality.

Effects of calcium levels and limestone particle size on the egg quality of semi-heavy layers in their second production cycle

A 112-day trial was carried out to evaluate the effect of dietary calcium level and limestone particle size on the egg quality of 288 Hy-Line Brown semi-heavy layers, with 83 weeks of age at the beginning of the experiment. A completely randomized experimental design was applied in a 2x3 factorial arrangement, with two dietary calcium levels (3.5 and 4.0%) e three limestone particle size compositions (100% fine limestone (FL), with 0.185mm; 30% coarse limestone (CL), with 2.83mm, + 70% FL, with 0.185mm; and 50% CL, with 2.83mm, + 50% FL, with 0.185mm), with six replicates of eight birds each. Mean geometric diameter and in-vitro solubility of the limestone sources were, respectively, 0.185mm and 18.7% for the fine limestone, and 2.83mm and 10.5% for the coarse limestone. At the end of each 28-day period, 72 eggs per treatment were used to determine egg specific gravity, yolk percentage, albumen percentage, eggshell percentage, yolk index, Haugh units, eggshell thickness, and eggshell breaking strength. There was no influence of the treatments on the evaluated parameters. It was concluded that feeding the level of 3.5% calcium usually recommended for layers in their first laying cycle, and the substitution of up to 50% fine limestone by coarse limestone in the feed of semi-heavy commercial Hy-Line Brown layers in their second laying cycle can be applied with no impairment of egg quality.

Effect of organic mineral supplementation on the egg quality of semi-heavy layers in their second cycle of lay

This study was carried out to evaluate the effects of dietary trace mineral levels and sources on egg quality parameters of second-cycle semi-heavy layers. A number of 360 72-week-old layers were submitted to forced molting. Upon return of lay (83 weeks of age), birds were distributed according to a completely randomized experimental design of six treatments with six replicates of 10 birds each. The control treatment consisted of 0.10% dietary supplementation of trace minerals from inorganic sources, which was proportionally replaced by five levels (110, 100, 90, 80, 70%) of an organic trace mineral supplement containing 30, 30, 40, 6, 0.61, and 0.3 g/kg product of Zn, Fe, Mn, Cu, I, and Se, respectively. All diets contained equal protein, energy, and amino acid levels. Every 28 days of the experimental period (112 days) four eggs per replicate were collected for egg quality evaluation. The following parameters were evaluated: specific gravity, yolk, albumen and eggshell percentages, yolk index, Haugh units, and eggshell thickness and breaking strength. One sample per replicate, consisting of the pool of the yolks of three eggs collected at the end of each experimental period, was used to assess protein and mineral (Ca, P, Cu, Fe, Mn, and Zn) contents. The results were submitted to ANOVA, and means to the test of Tukey at 5% significance level. The evaluated trace mineral levels and sources did not influence any of the studied egg quality parameters. It was concluded that reducing organic trace mineral supplementation in up to 70% relative to 100% inorganic trace mineral supplementation does not affect egg parameters and therefore, can be applied to the diet of semi-heavy layers in their second cycle of lay.

Effect of organic mineral supplementation on the egg quality of semi-heavy layers in their second cycle of lay

This study was carried out to evaluate the effects of dietary trace mineral levels and sources on egg quality parameters of second-cycle semi-heavy layers. A number of 360 72-week-old layers were submitted to forced molting. Upon return of lay (83 weeks of age), birds were distributed according to a completely randomized experimental design of six treatments with six replicates of 10 birds each. The control treatment consisted of 0.10% dietary supplementation of trace minerals from inorganic sources, which was proportionally replaced by five levels (110, 100, 90, 80, 70%) of an organic trace mineral supplement containing 30, 30, 40, 6, 0.61, and 0.3 g/kg product of Zn, Fe, Mn, Cu, I, and Se, respectively. All diets contained equal protein, energy, and amino acid levels. Every 28 days of the experimental period (112 days) four eggs per replicate were collected for egg quality evaluation. The following parameters were evaluated: specific gravity, yolk, albumen and eggshell percentages, yolk index, Haugh units, and eggshell thickness and breaking strength. One sample per replicate, consisting of the pool of the yolks of three eggs collected at the end of each experimental period, was used to assess protein and mineral (Ca, P, Cu, Fe, Mn, and Zn) contents. The results were submitted to ANOVA, and means to the test of Tukey at 5% significance level. The evaluated trace mineral levels and sources did not influence any of the studied egg quality parameters. It was concluded that reducing organic trace mineral supplementation in up to 70% relative to 100% inorganic trace mineral supplementation does not affect egg parameters and therefore, can be applied to the diet of semi-heavy layers in their second cycle of lay.

Alternative calcium source effects on commercial egg production and quality

This study aimed at verifying the possibility of replacing calcitic limestone by marine calcium in the diet of layers. A total number of 321 Hi-sex hens, with 40 weeks of age at the beginning of the experiment, was used. A completely randomized experimental design was applied, with 5 treatments (0, 15, 30, 45, and 60 % of calcitic limestone replacement by marine calcium source) and eight replicates of eight birds each. Treatments significantly affected specific gravity (p 0.05), with the inclusion of 60% marine calcium (T5) presenting the worst result as compared to T1, which included only calcitic limestone as calcium source. It was concluded that marine calcium can replace up to 45% of calcitic limestone with no effects on performance or egg quality.