Effects of grass feeding systems on ruminant meat colour and flavour. A review
Anim. Res.
Effects of grass feeding systems on ruminant meat colour and flavour. A review
Alessandro PRIOLO 0
Didier MICOL 0
Jacques AGABRIEL 0
0 Unité de Recherches sur les Herbivores, INRA Clermont-Ferrand-Theix , 63122 Saint-Genès-Champanelle , France
- Grass feeding has been reported to affect several meat quality characteristics, in particular colour and flavour. In this paper we have reviewed some differences in meat colour and flavour between ruminants fed concentrates and animals allowed to graze pasture. The possible factors influencing the differences have been also examined. We have examined a total of 35 experiments which report the effect of pasture vs concentrate finishing systems on beef meat colour. Meat from cattle raised on pasture is reported to be darker than meat from animals raised on concentrates if measured by objective (P < 0.001) as well as subjective (P < 0.05) methods. Several factors, not a specific one are responsible for this difference, variations in ultimate-pH and in intramuscular fat content between animals finished at pasture and those finished on concentrates, seem to play a major role. Diet also affects meat flavour in both sheep and cattle but the components involved seem to be different. In sheep pastoral flavour is mostly determined by the branched-chain fatty acids and 3-methylindole (skatole). An important role seems to be played also by some products of oxidation of linolenic acid and its derivates. In cattle the role of skatole seems to be less important than sheep because of the lack of the branched-chain fatty acids. The pastoral flavour seems to be mostly determined by products of oxidation of linolenic acid and its derivates which derives substantially from grass.
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espèces. Chez l’agneau les flaveurs particulières liées à un régime à base d’herbe serait
majoritairement déterminée par l’association d’acides gras ramifiés et de scatole (3 méthyle indole), et dans une
moindre mesure par des produits issus de l’oxydation de l’acide linolénique. Inversement chez le boeuf,
le rôle du scatole serait réduit par l’absence d’acides gras ramifiés, et la flaveur de la viande liée au
pâturage serait plutôt à relier à l’oxydation de l’acide linolénique provenant de l’herbe.
alimentation à base d’herbe / couleur de la viande / flaveur de la viande / ruminants
1. INTRODUCTION
Many factors influence ruminant meat
quality and all of them can be divided for
simplicity into two categories: factors
directly linked with the animal (breed, age,
sex, etc.) and factors external to the animal
(diet, weather, slaughtering procedures, etc.)
indicated by the generic expression
“environmental”. Among the environmental
factors, feeding plays an important role in the
determination of quality. However, the
specific effects of the dietary constituents on
meat quality are not easy to evaluate. The
feeding regime can have an influence on
animal growth rate and it is difficult to
establish if the meat characteristics are due to the
dietary components for their intrinsic
properties or if the diet has influenced growth
rate and the body composition in animals
[
48
]. Different carcass fatness could lead to
differences in the rate of rigor development
even if the carcasses are stored under the
same conditions [
59
]. This could influence
meat colour, tenderness, etc. In most of the
experiments that study the effect of a diet
on meat quality, the animals are slaughtered
at different ages (same weight, but
different growth rate) or at different weights (same
age and again different growth rate). This
problem is particularly evident when studies
make comparison between production
systems. Of course these experiments are
useful because they investigate real production
situations, however a correct interpretation
of the data is more difficult: how is it
possible to discriminate between the effects of
the diet on animal growth rate (and
indirectly on carcass and meat quality) and the
direct effects of the dietary constituents on
meat quality? Another problem of
interpretation of data is when a comparison of diets
on meat quality is made between animals
allowed to move freely and animals
restricted in feedlots. The effect of feeding
may be confounded with the different
physical activity.
The principal characteristic of herbivores
and ruminants in particular, is the capability
of the micro-organisms present in their gut
(or fore-stomach) to degrade (and utilise)
the cellulose. Ruminants convert forages
into products of high biological value,
useful for human nutrition (meat, milk, blood).
In recent years, however, the genetic
potential of the animals and the different
zootechnical practises have changed the situation. A
high-producing animal, has not the capacity
to ingest the energy requirements for his
high production, totally by forages and
requires concentrate supplementation.
Animals raised on different production
systems produce different concentrations of
volatile fatty acids (VFA) in (...truncated)