Maicon Sbardella

Time-response relationship of ractopamine feeding on growth performance, plasma urea nitrogen concentration, and carcass traits of finishing pigs1

Ractopamine hydrochloride (RAC) improves swine production efficiency by redirecting nutrients to favor muscle accretion rather than fat deposition. In the present study, the time-dependent effect of RAC feeding on performance, plasma urea N (PUN) concentrations, and carcass traits of finishing pigs were evaluated. In a 28-d growth study, 80 barrows (average initial BW = 69.4 ± 7.9 kg) were assigned to 1 of 5 treatments in a randomized complete block design with 8 replicate pens per treatment and 2 pigs per pen. The pigs were fed a corn-soybean meal-based diet with no added RAC (control) or 10 mg of RAC/kg fed for 7, 14, 21, or 28 d before slaughter. All diets were formulated to contain 0.88% standardized ileal digestible Lys (1.0% total Lys) and 3.23 Mcal of ME/kg. Individual pig BW and pen feed disappearance were recorded weekly to determine BW changes, ADG, ADFI, and G:F. Anterior vena cava blood samples were taken on d 28 for determination of PUN concentrations. After 28 d on trial, the pigs were slaughtered and carcass measurements made at 24 h postmortem. Overall, providing pigs with different RAC feeding durations did not affect the final BW and ADFI but resulted in a tendency (P = 0.09) for a linear increase in ADG and a linear improvement (P = 0.003) in G:F. No effect of RAC feeding was found for weekly ADFI. Weekly improvements (P < 0.05) in ADG and G:F were observed over the first 21 d of RAC feeding. However, the growth response declined (P < 0.05) in wk 4 of RAC treatment. The concentrations of PUN exhibited a quadratic decrease (P = 0.004) as the RAC feeding duration increased. Although RAC feeding did not affect any backfat measurements and carcass length, increasing the RAC feeding duration linearly increased HCW (P = 0.01), dressing percentage (P = 0.03), LM depth (P = 0.001), LM area (P < 0.001), muscle-to-fat ratio (P = 0.004), and predicted carcass lean percentage (P = 0.02). These results indicate that a greater growth rate was achieved within the first 21 d of RAC feeding whereas the magnitude of carcass response was directly dependent on the duration of RAC feeding.

Effects of dietary supplementation of red pepper (Schinus terebinthifolius Raddi) essential oil on performance, small intestinal morphology and microbial counts of weanling pigs

BACKGROUND Many strategies, such as the antibiotic growth promoters, have been developed to improve intestinal health and performance of newly weaned piglets. Natural products such as essential oils have been scientifically recognized as growth enhancer feed additives for weanling pigs, replacing the antibiotics. Therefore, it has been hypothesized that Brazilian red pepper could replace performance-enhancing antibiotics also in weanling pig diets. However, one experiment was conducted to determine the effects of dietary Brazilian red pepper essential oil or antimicrobial growth promoter on intestinal health and growth performance of weanling pigs. RESULTS No effects of treatments were observed on performance and organ weights (P > 0.05). Overall, both additives [red pepper essential oil (RPEO) or antibiotic (ANT)] increased gut Lactobacillus counts compared to negative control, as well as reduced villi density (P < 0.05). Animals fed diets containing 1.5 g kg-1 RPEO presented the lowest incidence of diarrhea (P < 0.05). CONCLUSION Our findings suggested that essential oil from Brazilian red pepper or chlorohydroxyquinoline added in weanling pig diets affect gut microbiota and histology without affecting performance and organ weights. In addition, there was an indication that high doses of essential oil could reduce the incidence of diarrhea.

Effects of dietary hop (Humulus lupulus L.) β-acids on quality attributes, composition and oxidative stability of pork meat: Hop β-acids affect lipid content and oxiodation of pork meat

BACKGROUND The effects of dietary levels of hop β-acids on physical attributes, lipid oxidation and chemical composition of pork meat were evaluated. Thirty-two castrated male pigs obtained from a complete block design feeding experiment (6.23 ± 0.42 kg initial body weight (BW) to 20.45 ± 0.95 kg final BW) and fed diets supplemented with 0, 120, 240 or 360 mg kg-1 hop β-acids during 35 days were slaughtered to sample longissimus dorsi muscle for meat analysis. RESULTS No effects (P > 0.05) of dietary hop β-acids were observed on meat physical attributes. Quadratic effects (P < 0.05) of hop β-acids were observed on lipid and protein contents and on thiobarbituric acid-reactive substance (TBARS) values of meatballs, whose equations allowed the estimation of dietary hop β-acid levels of 176, 169 and 181 mg kg-1 to provide up to 16.20% lipid reduction, 1.95% protein accretion and 23.31% TBARS reduction respectively. CONCLUSION Dietary hop β-acids fed to pigs might reduce lipid, increase protein and reduce lipid oxidation without affecting physical attributes of the pork meat.