Reduced intake of dietary lysine promotes accumulation of intramuscular fat in the longissimus dorsi muscles of finishing gilts.

摘要

Effect of dietary lysine levels on the intramuscular fat (IMF) content of pork (longissimus dorsi; LD) from finishing gilts (swine) was investigated. 11 swine from 2 litters aged 110 days were used. The average initial body wt. of the swine was 61.7 kg. 6 swine were assigned to the low lysine (LL) diet group (0.43 or 0.40% lysine) and 5 to the control group (0.65 or 0.68% lysine). The diets were iso-energetic and iso-protein, and contained all essential amino acids (excluding lysine) in the recommended amounts. The swine were fed these diets to a live wt. of 110 kg. Live wt. gain and feed efficiency tended to be lower in the LL group (P = 0.118 and P = 0.052, respectively). Swine from the LL group took 5 days longer to reach 110 kg (P < 0.01). Pork IMF content in the LL group was twice as high as that of the control group (6.7 vs. 3.5%; P < 0.01). The percentage of oleic acid in LL pork tended to be higher than that in the control group (P = 0.052), whereas the percentage of linoleic acid and the total percentage of PUFA were lower (P < 0.05). Free L-carnitine content was lower in LL pork (P < 0.05). The average abundance of peroxisome proliferator-activated receptor gamma mRNA in pork from the LL group was 3x higher than in that from the control group. The pork leptin mRNA abundance of the LL group was 3.3x higher than that of the control group (P < 0.01). Results suggest that higher adipogenesis activity, induced by a dietary LL level, may be involved in IMF accumulation promotion in the LD of swine.