Effects of lysine concentration of the diet on growth performance and meat quality in finishing pigs with high slaughter weights

Tae-Whan Park2, Eun-Yeong Lee1,3, Yeunhae Jung1,3, Yu Min Son1,3, Sang-Hyon Oh1, Doo-Hwan Kim1, Chul Young Lee2, Seon-Tea Joo1,3, Jae-Cheol Jang1,*
Author Information & Copyright
1Division of Animal Science, Gyeongsang National University, Jinju 52828, Korea.
2Department of Animal Resources Technology, Gyeongsang National University, Jinju 52725, Korea.
3Institute of Agricultural and Life Science, Gyeongsang National University, Jinju 52828, Korea.
*Corresponding Author: Jae-Cheol Jang, Division of Animal Science, Gyeongsang National University, Jinju 52828, Korea, Republic of. E-mail:

© Copyright 2023 Korean Society of Animal Science and Technology. This is an Open-Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License ( which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.


The present study aimed to investigate the feasibility of using a diet low in lysine content as a means for increasing the intramuscular fat (IMF) content and pork muscle quality of finishing pigs. Thirty-two crossbred gilts and barrows weighing approximately 80 kg were fed either a low-lysine diet (0.60%; <strong>Low-lys</strong>) or a control diet (0.80% lysine; <strong>Med-lys</strong>) under a 2 × 2 factorial arrangement of treatments. The animals were slaughtered at a 132-kg body weight (BW) on average, followed by physicochemical analyses and sensory evaluation on <italic>Longissimus </italic><italic>lumborum</italic> (<strong>LL</strong>) and <italic>Semitendinosus</italic> (<strong>ST</strong>) muscles. The average daily gain (ADG) did not differ between the Med-lys and Low-lys groups. However, ADG exhibited a tendency of sex × diet interaction (<italic>p</italic> = 0.09), being greater for barrows vs. gilts on the Low-lys diet (<italic>p</italic> &lt; 0.05), but not on the Med-lys diet. Backfat thickness adjusted for 132-kg BW also exhibited the interaction; it was greater for the Low-lys vs. Med-lys group within gilts but tended to be less for the former in barrows (<italic>p</italic> = 0.08). The IMF content was not influenced by the diet or sex in either LL or ST. The a*, b*, and Warner-Bratzler Shear Force values and fatty acid composition were influenced by the sex or diet in either or both of the muscles, but the treatment effects did not apparently influence the meat quality. Sensory scores for the flavor, juiciness, tenderness, umami, and palatability of cooked muscle were not influenced by the diet in either LL or ST. When the LL and ST data were pooled, scores for those sensory attributes were positively correlated with the IMF content, which was associated with overall greater IMF contents and greater sensory scores for ST vs. LL. Collectively, the Low-lysine diet seemingly elicited the intended lysine deficiency in gilts as indicated by the increased BFT due to the diet. However, the Low-lys diet was not effective for increasing the IMF deposition or eating quality of the pork muscle of finishing pigs slaughtered at high BW probably because its lysine content was not low enough to elicit either outcome.

Keywords: Finishing pig; Dietary lysine; Growth; Meat quality; Physicochemical characteristics; Sensory attributes