Selection for food conversion in broilers: Predicted responses to selection for economic efficiency

1. Body composition was determined in 9-week-old chickens sampled from four lines selected either for increased body-weight gain (line W), for increased food consumption (line F), for decreased food conversion ratio (line E), or at random (line C), after three, four and five generations of selection.2. After five generations of selection the proportions of carcass water (678 g/kg) and protein (187 g/kg) were highest in line E and lowest (636, 180 g/kg respectively) in line F. The proportion of fat was lowest (83 g/kg) in line E and highest (134 g/kg) in line F.3. Lines W and C were similar and intermediate to lines E and F for all the carcass constituents.4. There was more fat in females (115 vs 98 g/kg) and less protein (177 vs 190 g/kg) and water (652 vs 665 g/kg) than in males.5. Line differences in carcass composition were not appreciably altered if birds were killed at equal weight rather than equal age.

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“…How growth rate, efficiency and body composition may be optimally improved is considered by Pym and James (1979).…”

Section: Phenotypic Correlations Between Performance and Body Composimentioning

confidence: 99%

Selection for food conversion in broilers: Body composition of birds selected for increased body‐weight gain, food consumption and food conversion ratio

Pym

Solvyns

1979

British Poultry Science

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“…Traits significantly correlated with fat deposition that can be measured in a live chicken are feed conversion ratio and triglyceride content of blood plasma (Whitehead and Griffin, 1984). However, measurement of both characteristics is laborious and individual selection for feed conversion requires individual cages (Pym and James, 1979). Eitan et al (1982) and Leenstra et al (1986) found negative genetic correlations between body weight gain with restricted feeding and amount of abdominal fat deposited with ad libitum feeding.…”

Section: Introductionmentioning

confidence: 97%

Fat Deposition in a Broiler Sire Strain

Leenstra

Pit

1987

Poultry Science

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Four lines were selected from a broiler sire strain. Selection criteria were sib selection for a low amount of abdominal fat relative to body weight (AF line), individual selection for feed conversion (feed consumed/weight gain) from 21 to 42 days of age (FC line), individual selection for body weight after restricted feeding (GR line), and individual selection for body weight after ad libitum feeding (GL line). In the fifth generation lines were compared at 6 weeks of age for body weight, percent abdominal fat, feed conversion, slaughter yield, and chemical composition. Rankings of lines reared in groups on litter and in individual cages were the same for all traits examined. Lines GR and GL hardly differed, whereas lines AF and FC, compared with line GL, had, respectively, significantly lower body weights (-293 g and -228 g),less abdominal fat (-1.45% and -1.00%), better feed conversions (-.11 and -.17), and higher griller yields (.50% and .70%).Selection for body weight after restricted feeding was not effective in reducing fat deposition. When compared at the same age with the line selected for body weight after ad libitum feeding, sib selection against abdominal fat and selection for a better feed conversion reduced abdominal fat, improved feed conversion, and increased slaughter yields. (

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“…Farrell (1974) reported that prediction of fat by weight was improved by including information on tritiated water space. Selection based on efficiency of feed utilization has also been proposed as a criterion for indirectly reducing body lipid content (Pym, 1979;Pym and James, 1979). Pym and Thompson (1980) developed a set of calipers to specifically measure abdominal fat pad thickness in live birds.…”

Section: Introductionmentioning

confidence: 99%

Estimates of Heritability for Plasma Very Low Density Lipoprotein Concentration and Genetic Correlations with Lipid Content, Body Volume, and Density in Coturnix coturnix japonica

Garwood

1987

Poultry Science

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Genetic parameters associated with very low density lipoprotein concentration (VLDL) in a randombred population of Coturnix were estimated. Associated traits were: body density, volume, and weight of the live bird, and lipid content of the whole carcass. A total of 739 progeny by 50 sires and 126 dams was the basis of the data. The VLDL was highly heritable (.52) and highly correlated with lipid content (greater than .50) but correlated to lesser degrees with body density (.24) and body volume (.20). The genetic correlation estimates between VLDL and body weight were small relative to their standard errors.

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Selection for food conversion in broilers: Predicted responses to selection for economic efficiency

Cited by 13 publications

References 12 publications

Selection for food conversion in broilers: Body composition of birds selected for increased body‐weight gain, food consumption and food conversion ratio

Selection for food conversion in broilers: Body composition of birds selected for increased body‐weight gain, food consumption and food conversion ratio

Fat Deposition in a Broiler Sire Strain

Estimates of Heritability for Plasma Very Low Density Lipoprotein Concentration and Genetic Correlations with Lipid Content, Body Volume, and Density in Coturnix coturnix japonica

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