Effect of level of feed restriction during growth and/or fattening on fatty acid composition and lipogenic enzyme activity in heavy pigs
Daza, A., Rey, A.I., Menoyo, D., Bautista, J.M., Olivares, A., López-Bote, C.J. (2007). Animal Feed Science and Technology 138: 61-74
22-Nov-2007 (18 years 6 months 16 days ago)When meat is used to obtain high quality meat products, fatty acid composition
is an important issue. Different nutritional strategies are proposed in order
to increase the concentration of monounsaturated fatty acids, while decreasing
the proportion of polyunsaturated fatty acids. The experiment was carried out
to assess the importance of feeding level during the growing and fattening phases
on the composition of fatty acid of the meat. The experiment was carried out with
Iberian pigs which can represent a good model for producing high-quality meat
products.
Forty eight Iberian castrate pigs were divided into two groups: low feeding level
(L) during the growing period, and high feeding level (H) for the same period.
At the end of the growing period and with 80 kg body weight in L fed pigs, and
125 kg body weight in H fed pigs, animals present in each group were further divided
into two groups: receiving during the fattening period a high feeding level, and
a low feeding level, determining thus four experimental groups (LL, LH, HH, HL).
At the beginning of the fattening period ultrasonic measurements of Longissimus
dorsi muscle lean and backfat were carried out. Moreover, backfat biopsy
samples were taken at the beginning of the growing and fattening periods, and
after slaughtering. Chops from the Longissimus dorsi were obtained from
the carcasses in order to determine real measurements of lean and backfat thicknesses,
and of intramuscular fat content. Different activities of enzymes were evaluated
in the subcutaneous backfat.
The growing phase lasted for 163 days in alls groups, and then animals were slaughtered
at 153 kg body weight. The ages at slaughter were different depending on the feeding
plan: 383 days for HH, 406 for HL, 439 for LH, and 503 days for LL. The best feed
conversion ratio was found in the LH fed pigs. At the slaughtering, the LL regime
determined the higher values of loin depths, lower intramuscular fat percentage
in the Longissimus dorsi and the lower backfat thicknesses. In the subcutaneous
backfat samples the higher proportion of monounsaturated fatty acids were found
in LH and LL fed pigs (P< 0.05), being the lower values of saturated fatty
acids found in the LL fed pigs. Feeding high levels to the animals also determined
a higher lipogenic enzymatic activity in the subcutaneous backfat.
A marked effect of feeding level was found in the meat characteristics (in terms
of fatty acids) and on pig productivity, results showed that the highest monounsaturated
fatty acid concentration was higher in LL fed pigs, but the LL group spend a long
period to reach market weight . The LH strategy provided a reasonable fatty acid
composition while not extending too much the time to reach the market weight.