The influence of dietary lysine restriction during the finishing period on growth performance and carcass, meat, and fat characteristics of barrows and gilts intended for dry-cured ham production1

Abstract

A total of 120 pigs [Duroc × (Landrace × Large White); initial average BW: 100.3 ± 2.5 kg] were used to investigate the effects of sex (barrows and gilts) and dietary total Lys restriction (7.0, 6.5, and 6.0 g·kg(-1)) on growth performance and carcass, meat, and fat characteristics. Pigs were intended for high-quality dry-cured ham from Spain (called Teruel ham), and a minimum fat thickness at the gluteus medius muscle (GM) is required (16 mm) for carcasses to be acceptable. Animals were slaughtered when they reached 129.0 ± 3.6 kg of BW. There were 6 treatments arranged factorially (2 sexes × 3 dietary Lys concentrations) and 4 replicates of 5 pigs per treatment. Barrows consumed more feed (P = 0.001) and tended to have less G:F (P = 0.06) than gilts. Carcasses from barrows were fatter (P = 0.001) and had heavier main trimmed lean cuts (P = 0.008) than gilts. A greater proportion of final acceptable carcasses for Teruel ham (P = 0.001) was observed in barrows than in gilts because of the greater percentage of carcasses that fulfill the minimum fat depth at GM required (P = 0.001). Meat from barrows had greater content of intramuscular fat (P = 0.02) than meat from gilts. Also, subcutaneous fat from barrows had less proportion of PUFA than fat from gilts (P = 0.02). A reduction in dietary Lys concentration decreased ADG (P = 0.004) and ADFI (P = 0.001) in pigs. In addition, backfat depth (P = 0.007) and fat at GM (P = 0.07) increased as dietary Lys decreased. The proportion of carcasses that fulfilled the minimum fat depth at GM required for Teruel ham increased as dietary Lys decreased in feed, but this effect was greater in gilts than in barrows (sex × Lys, P = 0.02). Meat and fat quality was not influenced by dietary treatment. We conclude that different feeding programs with different dietary Lys concentrations may be needed for barrows and gilts intended for production of dry-cured hams where a minimum carcass fat depth is required.

Effects of sex and dietary lysine on performances and serum and meat traits in finisher pigs

“…Growth performances and serum metabolites The differences between sexes in productive traits were similar to those previously detected by other authors (Latorre et al, 2009;Rodríguez-Sanchez et al, 2011). The higher ADG showed by barrows during the finisher period in comparison with gilts was associated to an increase in ADFI resulting in a negative effect on FCR.…”

“…Also, ham from barrows tended to have lower protein content than ham from gilts with no significant difference on IMF content. To this respect, a higher IMF proportion was expected in meat from barrows, taking into account their fatter carcasses and in accordance with several authors Rodríguez-Sanchez et al, 2011). However, in this case, the differences were only numerical and the reason could be that, in many reports, animals are usually slaughtered at the same age and then gilts were lighter than barrows, which has influence on meat composition (Latorre et al, 2009), whereas, in this case, both sexes had similar BW, which would reduce the differences.…”

“…In addition, carcasses of gilts were longer and also tended to have longer hams than those of barrows. Rodríguez-Sanchez et al (2011) found similar size of carcass and ham for both sexes when animals were slaughtered at the same age (196 days old) but different BW (132 and 126 kg for barrows and gilts, respectively). Therefore, the age/BW could be responsible, at least in part, for these differences.…”

“…The clear response observed in Sex and dietary lysine level in finisher pigs Suárez-Belloch, Guada and Latorre productive performances to the restriction of dietary Lys (ADG decreased and FCR increased) confirms previous observations on the effectiveness of Lys to manipulate the pattern of growth. So, Rodríguez-Sanchez et al (2011) reported a linear decrease in ADG and ADFI as total dietary Lys was reduced from 7 to 6 g/kg in diets from 100 to 128 kg BW. Also, Jin et al (2010) found an impairment of ADG and FCR with 30% of Lys restriction over a control diet containing 6 g total Lys/kg.…”

“…The effects of Lys restriction during the finisher period are more controversial. Some authors (Bidner et al, 2004;Rodríguez-Sanchez et al, 2011) have reported a limited success to increase body fatness although Lys restriction contributed to lowering feeding cost. Whereas other authors (Cisneros et al, 1996;Daza et al, 2010) have found a positive effect on IMF content of meat.…”