Response of Leghorn Pullets to Protein and Energy in the Diet when Reared in Regular or Hot-Cyclic Environments

Leeson, S.; Summers, J. D.

doi:10.3382/ps.0680546

Cited by 24 publications

(17 citation statements)

References 13 publications

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“…Although differences in BWG of birds on 18 and 20% CP diets were not significant for most of the study period, birds on 20% CP diet consumed more feed than those on 18% CP diet. These observations were consistent with previous reports (Sengar, 1987;Leeson and Summers, 1989;Skinner et al, 1992) that birds on diets with relatively higher levels of CP consume more feed. The FCR was lower for SCWL birds on 18% than 20% CP diets at 1 and 3-6 weeks and also lower in WPR than SCWL birds.…”

Section: Body Weight Gain Feed Consumption and Feed Conversion Ratiosupporting

confidence: 93%

Heterosis for growth related traits in White Plymouth Rock and Single Comb White Leghorn reciprocal crosses reared under two crude protein regimens

Nahashon¹,

Ayorinde²,

Drummond³

et al. 1999

J. Anim. Feed Sci.

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Studies of dietary effects on heterosis for body weight gain (BWG) and feed conversion ratio (FCR) are few. In the present work, heterosis, heterosis due to sex chromosome, and maternal and line effects for BWG and FCR were compared in reciprocal crosses of White Plymouth Rock (WPR) and Single Comb White Leghorn (SCWL). These birds were reared on either 18 or 20% crude protein (CP) diets from hatch to 8 weeks. The WPR birds exhibited larger body weights and consumed more feed than the SCWL birds. Also WPR birds on 20% CP diet were larger than those on 18% CP diet. Although FCR of SCWL birds on 18% CP diet was lower than those on 20% CP diet at 1 and 3-6 weeks, FCR was lower in WPR than SCWL birds. Heterosis was higher at 18% CP diets and the average maternal and line effects for BWG were higher (P<0.05) for WPR than SCWL and at 18 than 20% CP diets. However, maternal effects for FCR of WPR progeny were higher at 20 than 18% CP diets. Average line effects were also higher for WPR than SCWL males and significant at 20% CP diets for both lines. Heterosis due to sex chromosome was significant (PO.05) and positive for BWG but negative for FCR. This study indicates that SCWL males and WPR females exhibited higher combining ability at 18 than 20% CP diets. The significant heterosis for BWG and FCR due to sex chromosomes and maternal effects suggest that these two traits are also affected by genes on the sex chromosome.

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Section: Body Weight Gain Feed Consumption and Feed Conversion Ratiosupporting

confidence: 93%

Heterosis for growth related traits in White Plymouth Rock and Single Comb White Leghorn reciprocal crosses reared under two crude protein regimens

Nahashon¹,

Ayorinde²,

Drummond³

et al. 1999

J. Anim. Feed Sci.

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“…Peak production levels of 90% or higher are common with some of the egg-laying breeds (such as Leghorns), after which production gradually declines until it descends to a level where the hens are consuming more money in feed than is produced in eggs. At this point the flock is either terminated or put through a molt to start a second laying cycle [2].…”

Section: Introductionmentioning

confidence: 99%

Influence of Varying Crude Protein Levels and Balanced Amino Acids on the Performance and Haematological Characteristics of Laying Hens at the Second Phase of Production

Adeyemo¹

2013

FNS

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Varying levels of dietary crude proteins and balanced amino acids were fed to layers for a period of eight weeks starting from the twenty-sixth week of age of birds and six weeks into egg production. Effects on performance and haematological characteristics were investigated at this second phase of production. Sixty Black Nera hens were randomly allotted into four (4) dietary treatments, containing the following levels of crude protein 14%, 15%, 16%, 17% and the metabolizable energy was iso-caloric for each treatment. The results showed that there were no significant differences (P > 0.05) observed for lymphocyte, Haemoglobin (Hb), Packed Cell Volume (PCV), Red Blood Cell (RBC) and White Blood Cell (WBC), these haematological parameters were within the range for healthy birds. Thus crude protein level of 14% can be used in diets of layers at the second phase of production provided that adequate amino acids are given, without adverse effect on egg laying, feed intake and measured blood parameters.

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“…Uma explicação para estas diferenças pode ser atribuída ao fato de a genética das aves de postura, atualmente, ser muito diferente e, segundo Leeson & Summers (1989), tem efeito na resposta da franga. O consumo de proteína bruta do tratamento à vontade entre 3 e 8 semanas de idade foi igual ao tratamento da equação de EM (Tabela 3), sendo superior ao controlado, que deveria apresentar consumo de proteína igual ao tratamento da equação.…”

Section: -Means Of Feed Intake (G) and Metabolizable Energy (Kcal) Anunclassified

“…Ao atingir a maturidade sexual, as aves necessitam, além de peso corporal adequado, de uma composição de carcaça ideal, levando em consideração tanto a massa magra, como a composição de gordura (Leeson & Summers, 1989), pois ambos parecem ter efeito no peso do ovo (Leeson & Summers, 1997). Os resultados de composição de carcaça obtidos neste experimento tiveram comportamento semelhante aos dados encontrados por Sakomura et al (1993), que, ao avaliarem o uso de equações de predição para poedeiras leves às 52 semanas de idade, também não encontraram diferenças nos teores de gordura e proteína.…”

Section: -Means Of Feed Intake (G) and Metabolizable Energy (Kcal) Anunclassified

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Avaliação de equações de predição de exigências energéticas na alimentação de frangas de postura

et al. 2004

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RESUMO -O objetivo do presente estudo foi testar a validade de equações de predição de exigências energéticas para frangas de postura, as quais foram determinadas em estudos anteriores realizados na Faculdade de Ciências Agrárias e Veterinárias da UNESPJaboticabal. O delineamento experimental utilizado foi o inteiramente casualizado com três tratamentos e seis repetições compostas por 18 aves no período de 3 a 8 semanas, 15 aves de 9 a 12 semanas e 12 aves de 13 a 18 semanas de idade. Os tratamentos consistiram em comparar três diferentes formas de se alimentar as aves: alimentação à vontade, alimentação de acordo com as recomendações para a linhagem e alimentação de acordo com as equações de predição das exigências de energia metabolizável (EM). Os tratamentos foram avaliados por intermédio do desempenho das aves durante o período de crescimento e na fase de produção. No período de 3 a 8 semanas de idade, as aves alimentadas de acordo com as equações de predição de EM apresentaram menor consumo de ração e de energia, o que determinou menor peso corporal e uniformidade insatisfatória. Em função dos resultados da fase de 3 a 8 semanas de idade, foi adotada uma correção na equação de predição das exigências de EM para as fases seguintes, acrescentando-se uma porcentagem de 37% sobre as exigências de EM para mantença, valor relativo às atividades das aves. Às 18 semanas de idade, a ingestão de EM foi maior para o tratamento à vontade, sendo que as aves de todos os tratamentos apresentaram peso corporal superior ao proposto pelo manual e boa uniformidade. O experimento teve continuidade durante a fase de produção, sendo que os tratamentos aplicados na fase de crescimento não afetaram o desempenho produtivo das aves.Palavras-chave: desempenho de frangas de postura, equação de predição, exigências energéticas Evaluation of Prediction Equations for Energy Requirements in Pullets FeedingABSTRACT -The objective of this work was to evaluate the validity of prediction equation of metabolizable energy requirements, that was previously determined at Faculdade de Ciências Agrárias e Veterinárias of UNESP -Jaboticabal. The pullets were distributed in a randomized design with three treatments and six replication of 18 pullets from 3 to 8 wk-age, 15 birds from 9 to 12 wk-age and 12 birds from13 to 18 wk-age. The treatments consisted of comparing the performance of pullets feeding according to: ad libitum feeding, the strain recommendation and prediction equations for metabolizable energy (ME) requirements. The effect of treatments was evaluated in the growing phase and during the production phase to verify the effect of programs feeding during the growing on the egg production. From 3 to 8 weeks, the ME prediction equations promoted less feed and ME intakes than other treatments, and consequently these pullets showed lower body weight and smaller uniformity. In the following phases, an addition of 37% to ME maintenance requirement was used in order to correct the ME requirement of prediction equation. At 18 weeks, the ad libitum...

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Response of Leghorn Pullets to Protein and Energy in the Diet when Reared in Regular or Hot-Cyclic Environments

Cited by 24 publications

References 13 publications

Heterosis for growth related traits in White Plymouth Rock and Single Comb White Leghorn reciprocal crosses reared under two crude protein regimens

Heterosis for growth related traits in White Plymouth Rock and Single Comb White Leghorn reciprocal crosses reared under two crude protein regimens

Influence of Varying Crude Protein Levels and Balanced Amino Acids on the Performance and Haematological Characteristics of Laying Hens at the Second Phase of Production

Avaliação de equações de predição de exigências energéticas na alimentação de frangas de postura

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