Direct and Correlated Responses to Long-Term Selection for Increased Body Weight and Egg Production in Turkeys

Nestor, Karl E.; Noble, D. O.; Zhu, J.; Moritsu, Yasuyoshi

doi:10.3382/ps.0751180

Cited by 90 publications

(30 citation statements)

References 47 publications

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“…This is in contrast to many breeds of domesticated chickens, whose reproductive activity is limited to egg production as a result of commercial practices (e.g. photoperiod manipulation, egg removal) and decreases in broodiness, hatchability and fertility as a consequence of selection for increased egg production (Emmerson et al, 1991;Nestor et al, 1996;Sewalem et al, 1998) (reviewed by Romanov, 2001). Therefore, given that non-domesticated, laying females must ensure that they have adequate resources to perform post-laying parental behaviours, they may limit lipid allocation to current egg production in exchange for allocating more energy towards self-maintenance (i.e.…”

Section: Metabolic Shifts In Vldl Particle Diameter Distributionmentioning

confidence: 99%

Characterization of very-low density lipoprotein particle diameter dynamics in relation to egg production in a passerine bird

Salvante

Lin

Walzem

et al. 2007

Journal of Experimental Biology

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SUMMARY During avian egg production, oestrogen mediates marked increases in hepatic lipid production and changes in the diameter of assembled very-low density lipoprotein (VLDL). A nearly complete shift from generic VLDL (∼70 nm in diameter), which transports lipids to peripheral tissues, to yolk-targeted VLDL (VLDLy) (∼30 nm), which supplies the yolk with energy-rich lipid, has been observed in the plasma of laying domestic fowl. We validated an established dynamic laser scattering technique for a passerine songbird Taeniopygia guttata, the zebra finch, to characterize the dynamics of VLDL particle diameter distribution in relation to egg production. We predicted that non-gallinaceous avian species that have not been selected for maximum egg production would exhibit less dramatic shifts in lipid metabolism during egg production. As predicted, there was considerable overlap between the VLDL particle diameter distributions of laying and non-laying zebra finches. But unexpectedly, non-laying zebra finches had VLDL diameter distributions that peaked at small particles and had relatively few large VLDL particles. As a result, laying zebra finches, in comparison, had diameter distributions that were shifted towards larger VLDL particles. Nevertheless,laying zebra finches, like laying chickens, had larger proportions of particles within proposed VLDLy particle diameter ranges than non-laying zebra finches (e.g. sVLDLy: 50% vs 37%). Furthermore, zebra finches and chickens had similar modal (29.7 nm in both species) and median (32.7 nm vs 29.6 nm) VLDL particle diameters during egg production. Therefore,although zebra finches and chickens exhibited opposing directional shifts in VLDL particle diameter distribution during egg production, the modifications to VLDL particle structure in both species resulted in the realization of a common goal, i.e. to produce and maintain a large proportion of small VLDL particles of specific diameters that are capable of being incorporated into newly forming egg yolks.)

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Section: Metabolic Shifts In Vldl Particle Diameter Distributionmentioning

confidence: 99%

Characterization of very-low density lipoprotein particle diameter dynamics in relation to egg production in a passerine bird

Salvante

Lin

Walzem

et al. 2007

Journal of Experimental Biology

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“…Similarly, highperformance athletes are known to downregulate their level of immune functions (Kumae et al 1994). Bayyari et al (1997) and gallopavo) Nestor et al (1996) Unfortunately, the costs of maintenance are intrinsically difficult to measure (Lochmiller & Deerenberg 2000). For example, downregulation of an immune function as a result of physical exercise or dietary restriction is suggestive of a maintenance cost (table 2) but not proof, as the downregulation may be necessary to avoid self-damage rather than reflecting a cost.…”

Section: (B) Use Costs: Maintenance and Deploymentmentioning

confidence: 99%

Variation in immune defence as a question of evolutionary ecology

Schmid‐Hempel

2003

Proc. R. Soc. Lond. B

629

564

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The evolutionary-ecology approach to studying immune defences has generated a number of hypotheses that help to explain the observed variance in responses. Here, selected topics are reviewed in an attempt to identify the common problems, connections and generalities of the approach. In particular, the cost of immune defence, response specificity, sexual selection, neighbourhood effects and questions of optimal defence portfolios are discussed. While these questions still warrant further investigation, future challenges are the development of synthetic concepts for vertebrate and invertebrate systems and also of the theory that predicts immune responses based on a priori principles of evolutionary ecology.

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“…Robustness may still be selected against when, for example, considering traits like short-term efficiency where the fastest gains are made by maximising the production component at the expense of 'non-productive' functions (Puillet et al, 2016). The ultimate examples of ignoring the need to maintain associated functions are in breeding programmes that have selected aggressively for increased meat production, for example, in young broilers, with relatively little direct consideration of the unfavourable consequences of this selection strategy for rapid growth on the ability of adult birds to reproduce (Nestor et al, 1996). The trade-off between milk production and reproduction in dairy cows has been extensively reviewed elsewhere (Berry et al, 2016).…”

Section: Friggens Blanc Berry and Puilletmentioning

confidence: 99%

Review: Deciphering animal robustness. A synthesis to facilitate its use in livestock breeding and management

Friggens

Blanc

Berry

et al. 2017

Animal

151

145

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As the environments in which livestock are reared become more variable, animal robustness becomes an increasingly valuable attribute. Consequently, there is increasing focus on managing and breeding for it. However, robustness is a difficult phenotype to properly characterise because it is a complex trait composed of multiple components, including dynamic elements such as the rates of response to, and recovery from, environmental perturbations. In this review, the following definition of robustness is used: the ability, in the face of environmental constraints, to carry on doing the various things that the animal needs to do to favour its future ability to reproduce. The different elements of this definition are discussed to provide a clearer understanding of the components of robustness. The implications for quantifying robustness are that there is no single measure of robustness but rather that it is the combination of multiple and interacting component mechanisms whose relative value is context dependent. This context encompasses both the prevailing environment and the prevailing selection pressure. One key issue for measuring robustness is to be clear on the use to which the robustness measurements will employed. If the purpose is to identify biomarkers that may be useful for molecular phenotyping or genotyping, the measurements should focus on the physiological mechanisms underlying robustness. However, if the purpose of measuring robustness is to quantify the extent to which animals can adapt to limiting conditions then the measurements should focus on the life functions, the trade-offs between them and the animal's capacity to increase resource acquisition. The time-related aspect of robustness also has important implications. Single time-point measurements are of limited value because they do not permit measurement of responses to (and recovery from) environmental perturbations. The exception being single measurements of the accumulated consequence of a good (or bad) adaptive capacity, such as productive longevity and lifetime efficiency. In contrast, repeated measurements over time have a high potential for quantification of the animal's ability to cope with environmental challenges. Thus, we should be able to quantify differences in adaptive capacity from the data that are increasingly becoming available with the deployment of automated monitoring technology on farm. The challenge for future management and breeding will be how to combine various proxy measures to obtain reliable estimates of robustness components in large populations. A key aspect for achieving this is to define phenotypes from consideration of their biological properties and not just from available measures.

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Direct and Correlated Responses to Long-Term Selection for Increased Body Weight and Egg Production in Turkeys

Cited by 90 publications

References 47 publications

Characterization of very-low density lipoprotein particle diameter dynamics in relation to egg production in a passerine bird

Characterization of very-low density lipoprotein particle diameter dynamics in relation to egg production in a passerine bird

Variation in immune defence as a question of evolutionary ecology

Review: Deciphering animal robustness. A synthesis to facilitate its use in livestock breeding and management

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