Abstract :
A promising tool to improve daily gain in pigs is the missense mutation (Asp298Asn) in the melanocortin-4 receptor (MC4R)
gene, especially in the Belgian pig industry where the slow-growing Pie´ train breed is very frequently used as the sire breed.
The MC4R is expressed in the appetite-regulating region of the brain where it regulates feed intake and energy balance.
The mutation has been associated with differences in fatness, daily gain and feed intake. However, less information on the
correlated effects on meat quality is available. In order to evaluate the influence of the MC4R mutation on carcass and meat
quality parameters, a total of 1155 pigs of a four-way cross were slaughtered at an average live weight of 109 kg, and data
about daily live-weight gain, carcass and meat quality were collected. Allelic frequencies were 0.69 for the G-allele (298Asp
variant or well-conserved variant) and 0.31 for the A-allele (298Asn variant or the mutated variant). Barrows and gilts were
almost equally distributed in this population with, respectively, 49.9% and 50.1%. Moreover, independent of this mutation,
the relationship between average daily gain (ADG) and carcass on the one hand and meat quality traits on the other hand
was evaluated in this population. A significant positive influence of the MC4R mutation on ADG (P,0.001) was found,
accompanied by a higher fat thickness (P,0.05) and a lower carcass lean meat content (P,0.01), whereas muscle thickness
and carcass conformation traits were not affected. The effects on meat quality traits were not significant, except for a lower
shear force (P50.054) and a higher intramuscular fat content (P50.052) in AA animals. In the longissimus, pH and pork
quality meter (PQM) values were not influenced, and effects on drip loss and colour were not apparent. Residual correlation
coefficients between ADG and carcass lean meat content on the one hand and meat quality traits on the other hand were
generally very low (| r|.0.1). Higher ADG, higher carcass fat thickness and lower carcass lean meat content were correlated
with slightly lower shear force values (| r|,0.1, P,0.05). In conclusion, in the studied population, the Asp298Asn mutation
in the MC4R gene was associated with improved daily gain, higher carcass fatness and almost no effect on meat quality traits.
Keywords :
carcass quality , average daily gain , 4 receptor , melanocortin , meat quality , pigs
