Ractopamine supplementation improves leanness and carcass yield, minimally affecting pork quality in immunocastrated pigs

Abstract

This study was carried out to determine the combining effects of feeding up to 15 mg kg -1 ractopamine (RAC) to physically castrated (PC) pigs or those injected with an anti-GnRF vaccine (IC), on growth performance during suckling, weaning, growing and finishing phases. Out of a total of 1,160 male piglets, 50 % were surgically castrated at age 7, while 50 % underwent immunization against GnRF on the 103 rd and 136 th day of life. A completely randomized design, with two treatments (PC and IC), was used from the 1 st until the 60 th day of life. Afterwards, 792animals, PC and IC, selected according to overall average weight (23.3 ± 0.69 kg) were allotted based on a completely randomized block design with a 2 × 4 factorial arrangement of treatments (castration categories × RAC levels) with 9 replications (11 animals) per main combination effect. IC growing pigs improved feed conversion due to lower average daily feed intake and higher average daily gain (ADG). During the finishing phase, both RAC and immunocastration increased body weight, but the effects were independent. RAC, on its own improved ADG and feed conversion. However, pigs fed 10 mg kg -1 RAC had higher blood lactate compared to those fed lower levels, suggesting that these animals were more susceptible to stress. Muscle depth was influenced only by RAC, whereas fat thickness was lower for IC. Lean meat increased and fat decreased in the shoulder and belly of IC; RAC had a positive effect on belly lean meat only.Either immunocastration or RAC inclusion (at least 5 mg kg -1 ) promoted muscle gain and fat reduction in pig carcass, adding value to pork.

Effects of Ferulic Acid Supplementation on Growth Performance, Carcass Traits and Histochemical Characteristics of Muscle Fibers in Finishing Pigs

“…Both compounds, FA and ractopamine, showed an anabolic effect. It is well documented that β-AA ractopamine improves several productive and carcass parameters [ 29 , 30 ]. ADG and feed conversion are the most important production parameters.…”

How do season, on-farm fasting interval and lairage period affect swine welfare, carcass and meat quality traits?

“…However, the absence of season effects in the present study may be explained by the low cortisol levels which evidently reflected good environmental and pre-slaughter handling conditions. Since pigs have limited abilities to heat loss, they are essentially susceptible to heat stress (Ingrain 1965;Adejumo and Egbunike 1988), which can explain the higher lactate concentrations found in pigs during summer (Dalla Costa et al 2018). In the literature, the effects of fasting interval on cortisol levels are contradictory.…”

Effects of sexual condition and ractopamine supplementation on the proteomic profile of pork meat

“…Another common practice used in swine production to improve growth performance and the percentage of lean meat in the carcasses without altering the meat quality is the supplementation with ractopamine hydrochloride (RAC). RAC is a β-adrenergic agonist used as growth-promoting in swine finishing diets that acts as a repartitioning agent, reducing adipose tissue nutrients and redirecting them to muscle protein synthesis (Almeida et al, 2012;Athayde et al, 2012;Costa et al, 2018). Several studies demonstrated that both immune castration and RAC supplementation add value to the swine meat and carcass (Athayde et al, 2012;Lowe et al, 2014;Rocha et al, 2014;Costa et al, 2018).…”

“…RAC is a β-adrenergic agonist used as growth-promoting in swine finishing diets that acts as a repartitioning agent, reducing adipose tissue nutrients and redirecting them to muscle protein synthesis (Almeida et al, 2012;Athayde et al, 2012;Costa et al, 2018). Several studies demonstrated that both immune castration and RAC supplementation add value to the swine meat and carcass (Athayde et al, 2012;Lowe et al, 2014;Rocha et al, 2014;Costa et al, 2018). Rocha et al (2014) demonstrated that immune castrated males (IC) receiving 7.5 mg/kg of RAC exhibited leaner carcasses compared to surgically castrated (SC) with or without RAC inclusion in the diet, maintaining pork quality and good welfare indicators.…”