Compensatory growth response in pigs, muscle protein turn-over and meat texture: effects of restriction/realimentation period

Abstract

The present experiment was designed to evaluate the effect of different time spans of ad libitum feeding of pigs prior to slaughter after a period of restricted feeding on performance and texture characteristics of the meat. Te n litters of five pigs (Duroc ✕ Landrace ✕ Large White crosses) were allocated to five feeding treatments (AA, R28A42, R43A27, R52A18 and R60A10) at the age of 70 days. AA-pigs were given ad libitum a concentrate diet from day 70 to slaughter at day 140 (approx. 100 kg live weight). R28A42, R43A27, R52A18 and R60A10 pigs were given food at a restricted level (0·6 of ad libitum) for 28, 43, 52 and 60 days, respectively, followed by ad libitum feeding for 42, 27, 18 and 10 days, respectively, until slaughter at day 140. All pigs that had been given food at a restricted level for a period (R28A42, R43A27, R52A18 and R60A10) showed a compensatory growth response in the subsequent ad libitum period. However, only pigs on ad libitum for a minimum of 27 days prior to slaughter (R28A42 and R43A27) had carcass weights and muscle mass similar to that of the control pigs (AA) at slaughter. The restricted feeding increased meat proportion, whereas the feeding strategies had no effect on technological meat quality traits (pH24, drip loss and CIE-colour traits: L*, a* and b*). During compensatory growth, protein turn-over was increased and positively related to the length of the ad libitum period as indicated by the concentration of elongation factor-2 (eEF-2) (P < 0·10), the activity of µ-calpain (P < 0·01) and the myofibrillar fragmentation index (MFI) 1 day post mortem in m. longissimus dorsi (P < 0·08) and the solubility of collagen (P < 0·01). Although not significant, the shear force at day 1 followed the same pattern of improvement as the MFI. The concentration of eEF-2 increased at a faster rate following transition to ad libitum feeding than did the activity of µ-calpain. This suggests that muscle protein synthesis increases at a faster rate after change to ad libitum feeding and reaches the same level as in the control pigs (AA) before muscle protein degradation. This time lag between the increase in protein synthesis and degradation could explain the compensatory growth response and it also suggests that in order to use the compensatory growth mechanism to improve tenderness, the optimal time of slaughter may not coincide with the period of highest growth rates, but may occur at a later stage, when muscle protein degradation is maximal. For pigs slaughtered at 100 kg live weight, we expect muscle protein degradation to be maximal some time beyond 42 days of ad libitum feeding prior to slaughter.

Effect of compensatory growth on performance, carcass composition and plasma IGF-1 in grower finisher pigs

“…In this study, IMF content in R pigs was lower than A pigs during the restriction period and slightly lower after refeeding for 2 days; however, there was no difference after full compensation. Therefore, compensatory growth appeared to modify carcass composition by increasing fat deposition, as indicated by the IMF weight reaching the same level as the control in the subsequent re-alimentation period, in agreement with Donker et al (1986), Therkildsen et al (2002), Kristensen et al (2004) and Heyer and Lebret (2007) who reported that IMF and/or back fat thickness were not different after refeeding.…”

“…Furthermore, as a proportion of carcass weight LD muscle of R pigs showed slightly higher value than A pigs at SL1 and SL2 (the absolute wet weight of the muscle was not significantly different at these points nor at SL3; data not shown), but this muscle was not different at SL3, suggesting that compensatory growth had no effect on muscle tissue weight but did influence internal organs. Overall, these results indicate that the compensatory growth during the re-alimentation period occurred due to increased internal organ weight and fat deposition in accordance with Mersmann et al (1987), Bikker et al (1996) and Therkildsen et al (2002 and. In this study, IMF content in R pigs was lower than A pigs during the restriction period and slightly lower after refeeding for 2 days; however, there was no difference after full compensation.…”

“…In this study, the improvement in DLWG was sufficient to compensate as the CI was 0.87. In contrast, Therkildsen et al (2002) reported that pigs offered 0.6 of ad libitum for 28 days then subsequent fully fed for 42 days had a CI 0.57. There was no effect on FCR during the restricted feed intake phase of compensatory growth feeding regime for all the groups; although not significant, the restriction phase did have a positive effect on FCR in the different groups with an improvement ranging from 2.3% (SL1) to 5.7% (SL3).…”

“…The level of restriction imposed on some pigs was 0.70 of ad libitum; this was within the experimental range. In the literature, there are descriptions of various levels of restriction being imposed, but these are usually fixed at a level, which is between 0.60 to 0.80 of ad libitum total feed intake, 0.6 Therkildsen et al, 2002), 0.7 or 0.8 (Prince et al, 1983), 0.65 (Heyer and Lebret, 2007) or 0.69 . Experimental protocols were approved by the appropriate Ethics Committee.…”

Desempenho e características de carcaça de suínos submetidos a diferentes programas de restrição alimentar na fase dos 30 aos 118 kg

“…Contudo, os resultados encontrados neste estudo corroboram os reportados por Barbosa et al (2002a,b), que aplicaram níveis de 5 a 15% de restrição com 2.083 e 2.252 kcal de energia líquida (EL) na dieta e também não Tabela 2 -Desempenho de suínos submetidos a quatro programas de restrição alimentar Therkildsen et al (2002), aplicando 40% de restrição alimentar no período dos 70 aos 140 dias de idade, observaram ao abate (100 kg PC) espessuras de toucinho semelhantes à dos animais sem restrição alimentar (Tabela 5).…”