Merit of Utilizing the Heritability of a Ratio to Predict the Genetic Change of a Ratio

Gunsett, F. C.

doi:10.2527/jas1987.654936x

Cited by 35 publications

(25 citation statements)

References 4 publications

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“…The superiority of residual feed consumption as a selection criterion appears to hold also in this case; the proportions of observed response in line RA versus observed response in line RE being similar to those indicated for feed conversion (32% and 53% in experiments 1 and 2, respectively). Although the RE line behaved as was expected, the observed response in the RA line was less than expected, confirming the problems that may appear when a ratio is used directly as a selection criterion (G unsett 1984, 1986, 1987; E ssl 1989; C ampo and R odriguez 1990; M elton and C olette 1993). In experiment 1, it was theoretically expected that the selection response would be similar in both lines, either for feed conversion ratio or residual feed consumption.…”

Section: Discussionsupporting

confidence: 69%

“…Direct selection on feed efficiency ratio may not be the best way to improve it, because (1) the statistical properties of ratios are poor and selection response can be erratic; (2) the use of a ratio as a selection criterion results in different responses in the component traits, which in addition cannot be predicted accurately; and (3) ratios may produce fallacious indications of economic efficiency (G unsett 1984, 1986, 1987; E ssl 1989; C ampo and R odriguez 1990; M elton and C olette 1993). Feed is used for production and maintenance, and selection against residual feed intake (the difference between actual feed intake and that predicted from the requirements for output and maintenance of body weight), may be a useful alternative to improve feed efficiency.…”

Section: Introductionmentioning

confidence: 99%

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Experimental comparison between selection for residual feed consumption and feed conversion ratio in Tribolium

Campo

Turrado

1998

J Animal Breeding Genetics

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Summary Selection for residual feed consumption based on genotypic regression (RE) was compared with selection for feed conversion ratio (RA) using two experiments of downward selection for feed efficiency in Tribolium castaneum. The first experiment was designed to decrease feed consumption: weight gain, with residual feed consumption being based on weight gain from 7 to 14 days and initial weight, whereas the second experiment was intended to decrease feed consumption: egg mass, with residual feed consumption being based on egg mass between 28 and 30 days and adult weight. There were four generations of selection with four replicates, and a selected proportion of 20%. For each replicate, an unselected control was produced. Responses observed for the feed conversion ratio differed significantly between lines (p < 0.05) in both experiments; the RE lines having the greatest responses. The superiority of residual feed consumption as a selection criterion also held when this trait was considered as the selection objective, with mean responses differing significantly between lines (p < 0.05). It is suggested that both traits describe similar aspects of feed efficiency. The selection criterion used in line RE was equivalent to a restricted selection index, as was expected. The observed responses in the RA line were less than expected, especially in experiment 1, confirming the problems that may appear when a ratio is used directly as a selection criterion. The realized heritability was greater in a RE line in both experiments, in agreement with the theoretical expectations. The results show that residual feed consumption based on genotypical regression was an efficient selection method with respect to efficiency of feed usage. Resumen Comparación experimental entre la selección para consumo residual y la selección para conversión de alimento en Tribolium La selección para consumo residual basado en la regresión genotípica (RE) fue comparada con la selección para conversión de alimento (RA) usando dos experimentos en Tribolium castaneum. El primer experimento se diseñó para disminuir el cociente consumo: ganancia de peso, estando basado el consumo residual en la ganancia de peso entre 7 y 14 días y el peso inicial. El segundo experimento trató de disminuir el cociente consumo: masa de huevos, basándose el consumo residual en la masa de huevos entre 28 y 30 días y el peso adulto. Se hicieron cuatro generaciones de selección con cuatro repeticiones y una proporción de selección del 20%. En cada repetición había un control sin seleccionar. Las respuestas obtenidas para la conversión de alimento diferían significativamente entre líneas en ambos experimentos (p < 0.05), teniendo la línea RE mayor respuesta. La superioridad de esta línea se mantenía al considerar el consumo residual como objetivo de selección. Esto sugiere que ambos caracteres describen aspectos similares de la eficiencia alimenticia. El criterio de selección usado en la línea RE fue equivalente a un índice de selección con restricción, como era de esperar. ...

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Section: Discussionsupporting

confidence: 69%

Section: Introductionmentioning

confidence: 99%

Experimental comparison between selection for residual feed consumption and feed conversion ratio in Tribolium

Campo

Turrado

1998

J Animal Breeding Genetics

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“…As a consequence, selecting directly on FCR or FER will lead to poor selection response (Lin 1980;Gunsett 1984) and does not enable an accurate prediction of genetic gain (Gunsett 1987). However, linear indexes combining body weight gain and FI can be designed which have optimal properties in terms of accuracy and achieved genetic gain (Turner 1959;Lin 1980;Gunsett 1984Gunsett , 1987Lin & Aggrey 2013). Alternatively, residual feed intake can also be used as the selection criterion, especially in multiple trait selection combining RFI and growth (Kennedy et al 1993).…”

Section: Introductionmentioning

confidence: 99%

Improving feed efficiency in fish using selective breeding: a review

Verdal

Komen

Quillet

et al. 2017

Reviews in Aquaculture

130

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Improving feed efficiency (FE) is key to reducing production costs in aquaculture and to achieving sustainability for the aquaculture industry. Feed costs account for 30–70% of total production costs in aquaculture; much work has been done on nutritional and husbandry approaches to improve FE but only a limited amount of research has been devoted to using genetics, despite its potential. This paper reviews past work to improve FE in fish using selective breeding and assess future directions. Direct selection on FE traits requires methods to measure individual feed consumption and estimate FE efficiently and accurately. This is particularly difficult to do in fish because of the environment in which they live. Many of the published studies on FE were found to be inaccurate because of methodological problems. The relatively low heritability estimates of FE traits in fish published to date are probably partly as a result of inaccurate measurements of feed intake. Improving ways to measure the individual feed intake with high accuracy will be critical to the successful application of genetics to improving FE. Indirect selection criteria that could be used to improve FE (including growth after starvation/refeeding, body composition, neuropeptides or hormone levels) are discussed. Promising approaches to measuring feed intake accurately that may enable these studies to be undertaken are identified. More work using these will be needed prior to assessing the practicality of the introduction of direct or indirect traits for FE in fish genetic improvement programmes.

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“…Researchers have been long interested in these kinds of traits and have proposed to genetically analyze them by using different statistical methods from those for regular quantitative traits (e.g. Sutherland 1965;Gunsett 1982Gunsett , 1984Gunsett , 1987. The ratio trait does not follow the normal distribution and subjects to a Cauchy distribution when its two component traits are independent of each other and normal (Hinkley 1969;Kendall and Stuart 1979).…”

Section: Introductionmentioning

confidence: 99%

Mapping genome-wide QTL of ratio traits with Bayesian shrinkage analysis for its component traits

Yang

Jin

2010

Genetica

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The ratio trait is defined as a ratio of two regular quantitative traits with normal distribution, which is distinguished from regular quantitative traits in the genetic analysis because it does not follow the normal distribution. On the basis of maximum likelihood method that uses a special linear combination of the two component traits, we develop a Bayesian mapping strategy for ratio traits, which firstly analyzes the two component traits by Bayesian shrinkage method, and then generates a new posterior sample of genetic effects for a ratio trait from ones of population means and genetic effects for the two component traits, finally, infers QTL for the ratio trait via post MCMC analysis for the new posterior sample. A simulation study demonstrates that the new method has higher detecting power of the QTL than maximum likelihood method. An application is illustrated to map genome-wide QTL for relative growth rate of height on soybean.

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Merit of Utilizing the Heritability of a Ratio to Predict the Genetic Change of a Ratio

Cited by 35 publications

References 4 publications

Experimental comparison between selection for residual feed consumption and feed conversion ratio in Tribolium

Experimental comparison between selection for residual feed consumption and feed conversion ratio in Tribolium

Improving feed efficiency in fish using selective breeding: a review

Mapping genome-wide QTL of ratio traits with Bayesian shrinkage analysis for its component traits

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