Effects of ractopamine and arginine dietary supplementation for sows on growth performance and carcass quality of their progenies1

Abstract

The objective of this study was to evaluate the effects of ractopamine (Rac) and Arg fed to pregnant sows from d 25 to 53 of gestation on fetal muscle development as well as the performance and carcass characteristics of the progeny. One hundred sows were divided into 4 treatments including a control diet, the control plus 1% Arg, the control plus 20 mg/kg Rac, and the control diet supplemented with both additives at the same levels as those used separately. During the farrowing process the data evaluated were the weight of placenta to calculate the placental efficiency and the number of piglets born alive, stillborn, and mummified. To evaluate the fiber number and area, 12 male piglets from each treatment were euthanized to harvest semitendinosus muscle. During the lactation, the preweaning mortality, weaned weights, and number of piglets weaned per litter were evaluated. After weaning, the pig performance was evaluated until the slaughter following the sow treatment. At end of finishing phase, 1 male pig of each treatment replicate was selected to evaluation the carcass and pork quality. All variables measured were analyzed using the MIXED procedure of SAS and least squares means were compared using the Tukey test with P < 0.05. The control diet + supplementation of 1.0% of L-Arg + 20 mg/kg of ractopamine HCl from d 25 to 53 of gestation (Arg+Rac) treatment had a greater number of stillborn piglets (P = 0.014) than the control group. Piglet birth weights from sows fed Rac were 11% greater (P = 0.031) than those of piglets of the control treatment. The semitendinosus muscle fiber diameters of piglets at birth from sows that received Arg, Rac, and Arg+Rac were greater (P < 0.0001) than those of control piglets, and as consequence, the fiber number per square millimeter decreased (P < 0.0001). The final nursery BW of progeny from sows fed Arg and Rac individually were greater (P = 0.010) than those of progeny of the control group. At 110 d of age, in the beginning of the finisher 1 phase, pigs from Arg-fed sows were 1.9 kg heavier (P = 0.010) than pigs from the Arg+Rac-fed sows. The HCW were 2.97 and 1.64 kg heavier (P < 0.0001) for progeny of the Arg and Rac sows, respectively, compared with those of progeny of the control. In conclusion, the trial showed that the use of Rac for gestating sows increased the piglets' weight at birth. The size of muscular fiber was increased in the semitendinosus muscle of piglets originating from sows receiving Rac or Arg. However, the combination of both compounds did not have an additive effect in comparison with the control treatment but increased the stillbirth number.

Impact of dietary l-arginine supply during early gestation on myofiber development in newborn pigs exposed to intra-uterine crowding

“…However, interestingly and in contrast to the present study, a lower TNF was observed in offspring from supplemented compared with unsupplemented sows. One explanation for the discrepancy between the observation in our study and the study of Garbossa et al [40] could be the mode of l -arginine supplementation, either during d 14-28 or 25-53 of gestation, respectively, and at either 0.89% or 1.00% of the diet, respectively. With these combined results in mind, it is relevant to reflect on the extent to which supplementary l -arginine is directing dietary energy for hyperplasia or hypertrophy in fetuses during the different phases of gestation.…”

“…This finding contradicts our hypothesis that underprivileged fetuses would preferentially benefit from ARG supplementation by an increased placental vascularization. Results of a recent study [40] suggested that supplementing the gestational diet with either l -arginine, ractopamine, or a combination of the two increased myofiber diameter, indicating that supplementation had an effect on muscle fiber hypertrophy rather than hyperplasia. Ultimately, this resulted in a lower proportion of low BtW piglets (< 0.8–1.2 kg BtW), and an increased proportion of medium and high BtW piglets (> 1.2–1.6 kg BtW) from l -arginine supplemented compared with unsupplemented sows [40].…”

“…Results of a recent study [40] suggested that supplementing the gestational diet with either l -arginine, ractopamine, or a combination of the two increased myofiber diameter, indicating that supplementation had an effect on muscle fiber hypertrophy rather than hyperplasia. Ultimately, this resulted in a lower proportion of low BtW piglets (< 0.8–1.2 kg BtW), and an increased proportion of medium and high BtW piglets (> 1.2–1.6 kg BtW) from l -arginine supplemented compared with unsupplemented sows [40]. However, interestingly and in contrast to the present study, a lower TNF was observed in offspring from supplemented compared with unsupplemented sows.…”

Variability of piglet birth weights: A systematic review and meta‐analysis

“…In the current study, amino acids supplementation was given in the third trimester of gestation most of the trials (60%), which could explain the results for litter size. However, despite the differences in methodology, amino acid supplementation has shown positive effects on the variability of piglet birth weight (Athorn, Wilkinson, & Henman, 2017;Dallanora et al, 2017;Garbossa et al, 2015).…”

<b>Adição de ractopamina à nutrição de fêmeas suínas gestantes:</b> quais os impactos sobre o neonato?

“…As fêmeas são muito mais sensíveis à suplementação proteica nessa fase em comparação com outras fases. A demanda de proteína pode ser suprida através de dietas contendo fontes de ingredientes vegetais ou animais e complementada com a adição de aminoácidos industriais (BOYD et al, 2002;PETTIGREW;YANG, 1997 Garbossa et al (2015) observaram que leitões nascidos de matrizes com dietas suplementadas com 20 mg/kg de ractopamina durante 25 a 50 dias de gestação podem apresentar taxas de crescimento mais elevadas, aumentando a deposição muscular da carcaça, melhorando a viabilidade econômica.…”