Elsevier

Meat Science

Volume 83, Issue 1, September 2009, Pages 127-134
Meat Science

The effects of a mutation in the myostatin gene on meat and carcass quality

https://doi.org/10.1016/j.meatsci.2009.04.010Get rights and content

Abstract

This study examined the effects of a mutation that inactivates the myostatin gene on calving, growth, carcass and meat quality traits in South Devon cattle. This breed carries at intermediate frequency an 11-bp deletion (MH) in the myostatin gene, known to be associated with the double-muscling phenotype, thus allowing a comparison of three genotype classes. The MH allele was associated with increased calving difficulty, carcass weight, muscle conformation and ratio of polyunsaturated to saturated fatty acids, as well as with reduced growth rate, carcass and meat fatness, and desirable flavour. However, the nature of the genetic effects differed between traits: in some cases the heterozygote MH carriers were more similar to the non-carriers than to homozygote carriers and in some cases, intermediate between the two homozygotes. The direction of these genetic effects has implications for the management of this genetic variation in the South Devon and other breeds.

Introduction

The myostatin gene (also known as GDF-8) regulates development of muscle and inactivation of this gene or the gene products results in extended muscular development. The effects of the gene were first described in mice, where loss of myostatin expression in knock-out mice was associated with both an increase in the number of muscle fibres (hyperplasia) and an increase in fiber size (hypertrophy) (McPherron, Lawler, & Lee, 1997). Later, an extreme form of muscularity (“double muscling”) seen in the Belgian Blue and Piedmontese cattle breeds was shown to result from mutations in the coding region of the myostatin gene (Grobet et al., 1997, Kambadur et al., 1997, McPherron and Lee, 1997). In the case of the Belgian Blue, the mutation is an 11-bp deletion in the third exon, while the Piedmontese carries a point mutation in the same exon. Other heavily muscled cattle breeds have also been shown to carry polymorphisms in the myostatin gene (Dunner et al., 2003, Grobet et al., 1998), lending support to this being the causative gene for the “double muscled” phenotype. Myostatin is a negative growth factor that inhibits both the terminal differentiation of myoblasts (Langley et al., 2002, Rios et al., 2002) and the proliferation of myogenic cells (Thomas et al., 2000). The myostatin gene has been shown to influence muscle metabolism and gene expression (Cassar-Malek et al., 2007, Hocquette et al., 2007, Hocquette et al., 1998, Potts et al., 2003). In cattle, the effects of myostatin are seen during foetal development, where the loss of myostatin function affects muscle fibre development and results in hyperplasia (Deveaux, Picard, Bouley, & Cassar-Malek, 2003). Double-muscled cattle have been reported to have substantially greater numbers of muscle fibres than non-double-muscled animals at birth (Gerrard & Judge, 1993) and at slaughter, a greater proportion of muscle and lower proportions of bone and fat (Ansay and Hanset, 1979, Arthur, 1995, Clinquart et al., 1998, Ménissier, 1982).

An earlier report showed that the South Devon cattle breed carries, at moderately high frequency, the 11-bp deletion first reported in the Belgian Blue (Smith, Lewis, Wiener, & Williams, 2000). It was subsequently shown that this allele is associated with increased muscling, calving difficulty, and decreased fat depth in this breed (Wiener, Smith, Lewis, Woolliams, & Williams, 2002). These observations were in agreement with those of others on the effects of myostatin mutations in different breeds. Alleles associated with increased muscling have also been associated with variation in other traits, including collagen content, meat colour, energy metabolism and hormone levels (Bellinge et al., 2005, Hocquette et al., 1998). These characteristics may affect the quality of meat produced from animals carrying different myostatin alleles (Aldai et al., 2006, Oliván et al., 2004), although there have been conflicting reports on the effects of double muscling on meat tenderness (Arthur, 1995).

Consumers define meat quality initially in terms of appearance, particularly colour and visible fat, to guide selection at purchase, and then, at the time of consumption, primarily by texture and flavour (Colmenero, 1996, Neely et al., 1998). However, consumers are now also considering health implication of meat composition, e.g. poly-unsaturated versus saturated fat, in purchase choices. In addition to effects of nutrition, animal management and carcass treatment on carcass and meat quality traits, genetic factors also play a significant role (Wheeler, Cundiff, Shackelford, & Koohmaraie, 2004). Among the genetic factors, the full impact of myostatin genotype on meat-related traits requires further clarification.

The quality of meat from double-muscled breeds has been compared with meat produced from normal cattle of other breeds, however, in these cases, the observed variation may be an effect of differences in genetic background rather than of myostatin genotype. Few studies have compared phenotypes of animals from the same breed with different myostatin genotypes. The current study examined variation in growth rate, carcass characteristics, and meat quality from British South Devon cattle with different myostatin genotypes. This comparison allowed us to directly investigate the effect of the myostatin gene on traits of economic importance within the same genetic background.

Section snippets

Study population

Most of the animals in the study population came from 12 farms where blood samples of calves and parents as well as detailed calving records were collected. Additional blood samples were collected at abattoirs at the time of slaughter. Animals were managed, recorded and slaughtered according to commercial farm practices.

Calving and growth data

Data on calving included sex, weight at birth, calving score (1–5, increasing with the difficulty of the calving), whether the calf was a twin, and if the animals died at birth.

Results

A summary of the effects of myostatin gentoype for traits other than growth is shown in Table 1. Additive, dominance and substitution effects are given in Table 2.

Discussion

The results presented here suggest that the myostatin allele with the 11-bp deletion (MH) segregating in the South Devon breed affects several traits related to beef production. Some of the effects could be considered as advantageous from the point of view of the producer, while others are disadvantageous. In the present study the MH allele was associated with heavier calves at birth but slower growth, leading to lighter adult animals. However, although adult MH/MH animals had a lower

Acknowledgements

We are very grateful for the enthusiastic participation of the South Devon Herd Book Society without whom this project could not have been completed. Particular thanks go to Caroline Poultney and the other staff at the Society. We also acknowledge assistance from Tim King (Roslin), Victoria Bingham (Roslin), Kevin Gibson (Bristol), Duncan Marriott (Bristol), Ann Baker (Bristol), Kim Matthews (EBLEX Ltd.) and the following participating abattoirs: Jaspers Treburley Ltd., ABP York, St. Merryn

References (50)

  • B. Langley et al.

    Myostatin inhibits myoblast differentiation by down-regulating MyoD expression

    Journal of Biological Chemistry

    (2002)
  • M. Oliván et al.

    Effect of muscular hypertrophy on physico-chemical, biochemical and texture traits of meat from yearling bulls

    Meat Science

    (2004)
  • M. Thomas et al.

    Myostatin, a negative regulator of muscle growth, functions by inhibiting myoblast proliferation

    Journal of Biological Chemistry

    (2000)
  • L. Uytterhaegen et al.

    Effects of double-muscling on carcass quality, beef tenderness and myofibrillar protein-degradation in Belgian Blue White bulls

    Meat Science

    (1994)
  • H.E. Warren et al.

    Effects of breed and a concentrate or grass silage diet on beef quality in cattle of 3 ages II: Meat stability and flavour

    Meat Science

    (2008)
  • P.F. Arthur

    Double muscling in cattle: A review

    Australian Journal of Agricultural Research

    (1995)
  • R.H.S. Bellinge et al.

    Myostatin and its implications on animal breeding: A review

    Animal Genetics

    (2005)
  • E. Casas et al.

    Association of myostatin on early calf mortality, growth, and carcass composition traits in crossbred cattle

    Journal of Animal Science

    (2004)
  • E. Casas et al.

    Association of the muscle hypertrophy locus with carcass traits in beef cattle

    Journal of Animal Science

    (1998)
  • Cassar-Malek, I., Passelaigue, F., Bernard, C., Leger, J., & Hocquette, J. F. (2007). Target genes of myostatin...
  • J.L. Clinquart et al.

    The influence of double muscling on production and quality of meat in Belgian Blue cattle

    INRA Productions Animales

    (1998)
  • Commission of the European Communities (1982). European Communities beef carcass classification regulations. Council...
  • F. Coopman et al.

    Comparison of external morphological traits of newborns to inner morphological traits of the dam in the double-muscled Belgian Blue Beef breed

    Journal of Animal Breeding and Genetics

    (2004)
  • V. Deveaux et al.

    Location of myostatin expression during bovine myogenesis in vivo and in vitro

    Reproduction Nutrition Development

    (2003)
  • S. Dunner et al.

    Haplotype diversity of the myostatin gene among beef cattle breeds

    Genetics Selection Evolution

    (2003)
  • Cited by (0)

    View full text