Influence of probiotics in different energy and nutrient density diets on growth performance, nutrient digestibility, meat quality, and blood characteristics in growing-finishing pigs

Posted in: Energy, Meat Quality, Production by admin on August 5, 2011 | No Comments

The study was conducted to determine the effects of probiotics (Bacillus subtilis endospore and Clostridium butyricum endospore complex) supplementation and different energy and nutrient densities on growth performance, nutrient digestibility, and meat quality in growing-finishing pigs. A total of 96 pigs with initial BW of 47.50 kg were used in a 10-wk experiment. Pigs were randomly allotted to 1 of 4 treatments in a 2 × 2 factorial arrangement of treatments with 2 levels of energy and nutrient density (low and high energy, CP, and Lys) and 0.2% probiotics according to their sex and BW (6 pens, with 2 gilts and 2 barrows/pen). From 0 to 5 wk, ADG and G:F, as well as the apparent total tract digestibility (ATTD) of N and energy, were improved in the probiotic groups and in the high-energy and high-nutrient-density groups. From 6 to 10 wk, ADG and G:F, as well as the ATTD of DM, N, and energy, were increased when pigs were fed the high-energy and high-nutrient- density diets. Pigs fed the probiotic supplement or the high-energy and high-nutrient-density diets had increased ADG and G:F overall. Moreover, pigs fed the high-energy and high-nutrient-density diets had increased meat color scores, marbling scores, drip loss values, pH, and LM area compared with those fed the low-energy and low nutrient- density diets, whereas the probiotic treatment groups had increased meat color scores, marbling scores, and redness values. The lightness and yellowness values in the low-energy and low-nutrient density dietary treatments were greater than those in the high-energy and high-nutrient-density dietary treatments. Interactive effects of dietary energy and nutrient density and probiotics were also observed on the digestibility of N at wk 10 and energy at wk 5, as well as on meat firmness at the end of the experiment. In conclusion, dietary supplementation of probiotics increased growth performance throughout the experiment and exerted beneficial effects on ATTD. Meat quality was improved when pigs were fed high energy and high-nutrient-density diets.

For more information the full article can be found at http://jas.fass.org/

Quantitative trait loci analysis of swine meat quality traits

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A QTL study was performed in large half-sib families to characterize the genetic background of variation in pork quality traits as well as to examine the possibilities of including QTL in a marker-assisted selection scheme. The quality traits included ultimate pH in LM and the semimembranosus, drip loss, and the Minolta color measurements L*, a*, and b* representing meat lightness, redness, and yellowness, respectively. The families consist of 3,883 progenies of 12 Duroc boars that were evaluated to identify the QTL. The linkage map consists of 462 SNP markers on 18 porcine autosomes. Quantitative trait loci were mapped using a linear mixed model with fixed factors (sire, sex, herd, month, sow age) and random factors (polygenic effect, QTL effects, and litter). Chromosome-wide and genome-wide significance thresholds were determined by Peipho’s approach, and 95% Bayes credibility intervals were estimated from a posterior distribution of the QTL position. In total, 31 QTL for the 6 meat quality traits were found to be significant at the 5% chromosome- wide level, among which 11 QTL were significant at the 5% genome-wide level and 5 of these were significant at the 0.1% genome-wide level. Segregation of the identified QTL in different families was also investigated. Most of the identified QTL segregated in 1 or 2 families. For the QTL affecting ultimate pH in LM and semimembranosus and L* and b* value on SSC6, the positions of the QTL and the shapes of the likelihood curves were almost the same. In addition, a strong correlation of the estimated effects of these QTL was found between the 4 traits, indicating that the same genes control these traits. A similar pattern was seen on SSC15 for the QTL affecting ultimate pH in the 2 muscles and drip loss. The results from this study will be helpful for fine mapping and identifying genes affecting meat quality traits, and tightly linked markers may be incorporated into marker-assisted selection programs.

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Effect of distillers dried grains with solubles and ractopamine (Paylean) on quality and shelf-life of fresh pork and bacon

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Pigs (n = 240) were allotted in a 5 × 2 factorial arrangement with 5 levels of distillers dried grains with solubles (DDGS): 0, 15, 30, 45, and 60%, and 2 ractopamine (RAC) levels: 0 and 5 mg/kg. Four pigs per pen (2 barrows, 2 gilts) closest to pen mean BW were used for meat quality evaluation. Loins (n = 119) were evaluated for objective color; moisture and fat; subjective color, marbling, and firmness; and drip loss. Bellies (n = 119) were evaluated for weight, length, width, thickness, objective fat color, and firmness. Cured bellies were evaluated for pump yield, cook loss, and sliced bacon cook loss. Loin thiobarbituric acid reactive substances (TBARS) were evaluated on enhanced (salt and phosphate) boneless chops held in modified atmosphere (80% O2/20% CO2) packages for 0, 7, 14, and 21 d. Bacon TBARS were evaluated on sliced bacon held in vacuum packages for 0, 28, 56, and 84 d. Fat samples were collected from each jowl and belly and evaluated for fatty acid profile and iodine value (IV). Increasing DDGS decreased subjective marbling and firmness, and increased drip loss. Distillers dried grains with solubles did not affect loin pH, subjective or objective color, percent moisture, or percent fat. The RAC decreased subjective color, marbling, and a*. Increasing DDGS decreased belly weight, length, thickness, and firmness; decreased belly fat L*; and increased belly cook loss. Ractopamine did not affect any belly measurements, and there were no DDGS × RAC interactions. Distillers dried grains with solubles did not affect loin TBARS at 0, 7, or 14 d. At 21 d, loin TBARS from 30, 45, and 60% DDGS groups were increased compared with 0 and 15% groups. Ractopamine did not affect loin TBARS, and there were no DDGS × RAC interactions. Distillers dried grains with solubles and RAC did not affect bacon TBARS. Increasing DDGS increased belly and jowl IV, and decreased MUFA:PUFA in belly and jowl fat. Ratio of SFA:unsaturated fatty acids decreased in jowl and belly fat. Ractopamine did not affect fatty acid profiles or IV, and there were no DDGS × RAC interactions. Results indicate that increased DDGS have minimal effects on loin quality, but decrease belly quality, bacon processing characteristics, and fat stability. Ractopamine does not negatively affect these characteristics and does not interact with DDGS.

Effects of different moving devices at loading on stress response and meat quality in pigs

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Although there is increasing evidence regarding the negative welfare and meat quality implications of electric prod use for slaughter-weight pigs, this handling tool continues to be used. Therefore, the behavioral and physiological response and carcass and meat quality of 360 pigs being loaded onto a truck for transportation to slaughter according to 3 handling procedures were studied. The 3 handling procedures were 1) moving with an electric prod and board from the finishing pen to the truck (EP); 2) moving with a board and a paddle from the finishing pen to the truck (PAD); 3) moving with a board and a paddle from the finishing pen and using a compressed air prod in the ramp before going into the truck (CAP). A subpopulation of 144 pigs (48 pigs/treatment) was equipped with heart rate monitors. Blood samples were collected from the same animals at exsanguination for the analysis of creatine phosphokinase and lactate. Data were analyzed using an ANOVA for factorial design, with the animal as the experimental unit. Behavior was analyzed with MIXED model procedure with treatment as a fixed effect. During loading, EP pigs slipped and fell and overlapped more often, but stopped and attempted turns less often than CAP or PAD. With CAP, pigs made more 180° turns than with PAD or EP. Loading with EP led to more and longer vocalizations than loading with CAP or PAD. Loading took longest with CAP and was quickest with EP. Pigs handled with EP had a greater heart rate than those moved with PAD and CAP at loading, wait at loading, at unloading, and in lairage. Pigs loaded with EP had greater lactate concentrations in blood at exsanguination compared with pigs handled with CAP, with pigs loaded with PAD being intermediate. Furthermore, ultimate pH values in the semimembranosus and adductor muscles of EP pigs were greater compared with those from PAD and CAP pigs. Greater incidence of blood-splashed hams was found in EP pigs compared with PAD and CAP pigs. Therefore, considering animal welfare, carcass bruising, and blood splashes standpoints, EP should be replaced with PAD or CAP. However, additional research is necessary to identify methods that improve the loading efficiencies of PAD and CAP without adversely affecting animal welfare parameters.

Revealing genetic relationships between compounds affecting boar taint and reproduction in pigs

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Boar taint is characterized by an unpleasant taste or odor in intact male pigs and is primarily attributed to increased concentrations of androstenone and skatole and to a lesser extent by increased indole. The boar taint compounds skatole and indole are produced by gut bacteria, metabolized in the liver, and stored in the fat tissue. Androstenone, on the other hand, is synthesized in the testis along with testosterone and estrogens, which are known to be important factors affecting fertility. The main goal of this study was to investigate the relationship between genetic factors involved in the primary boar taint compounds in an attempt to discover ways to reduce boar taint without decreasing fertility-related compounds. Heritabilities and genetic correlations between traits were estimated for compounds related to boar taint (androstenone, skatole, indole) and reproduction (testosterone, 17β-estradiol, and estrone sulfate). Heritabilities in the range of 0.47 to 0.67 were detected for androstenone concentrations in both fat and plasma, whereas those for skatole and indole were slightly less (0.27 to 0.41). The genetic correlations between androstenone in plasma and fat were extremely high (0.91 to 0.98) in Duroc and Landrace. In addition, genetic correlations between androstenone (both plasma and fat) and the other sex steroids (estrone sulfate, 17β-estradiol, and testosterone) were very high, in the range of 0.80 to 0.95. Furthermore, a genome-wide association study (GWA) and a combined linkage disequilibrium and linkage analysis (LDLA) were conducted on 1,533 purebred Landrace and 1,027 purebred Duroc to find genome regions involved in genetic control of the boar taint compounds androstenone, skatole, and indole, and sex hormones related to fertility traits. Up to 3,297 informative SNP markers were included for both breeds, including SNP from several boar taint candidate genes. From the GWA study, we found that altogether 27 regions were significant at a genome-wide level and an additional 7 regions were significant at a chromosomal level. From the LDLA study, 7 regions were significant on a genome-wide level and an additional 7 regions were significant at a chromosomal level. The most convincing associations were obtained in 6 regions affecting skatole and indole in fat on chromosomes 1, 2, 3, 7, 13, and 14, 1 region on chromosome 6 affecting androstenone in plasma only, and 5 regions on chromosomes 3, 4, 13, and 15 affecting androstenone, testosterone, and estrogens.

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Comparisons of different muscle metabolic enzymes and muscle fiber types in Jinhua and Landrace pigs

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Western and indigenous Chinese pig breeds show obvious differences in muscle growth and meat quality, however, the underlying molecular mechanism remains unclear. The main objective of this study was to evaluate the breed-specific mechanisms controlling meat quality and postmortem muscle metabolism. The specific purpose was to investigate the variations in meat quality, muscle fiber type, and enzyme activity between local Jinhua and exotic Landrace pigs at the same age (180 d of age), as well as the same BW of 64 kg, respectively. We compared differentially expressed muscle fiber types such as types I and IIa (oxidative), type IIb (glycolytic), as well as type IIx (intermediate) fibers in LM and soleus muscles of Jinhua and Landrace pigs using real-time reverse-transcription PCR. Furthermore, the metabolic enzyme activities of lactate dehydrogenase, as well as succinic dehydrogenase and malate dehydrogenase, were used as markers of glycolytic and oxidative capacities, respectively. Results showed that Jinhua pigs exhibited greater intramuscular fat content and less drip loss compared with the Landrace. Meanwhile, the mRNA abundance of oxidative and intermediate fibers was increased in Jinhua pigs, whereas the glycolytic fibers were more highly expressed in the Landrace. In addition, Jinhua pigs possessed greater oxidative capacity than that of the Landrace. These results suggested that the increased expression of the oxidative and intermediate fibers and greater activities of oxidative enzymes in Jinhua pigs were related to meat quality as indicated by a greater intramuscular fat and reduced drip loss. Based on these results, we conclude that muscle fiber composition and postmortem muscle metabolism can explain, in part, the variation of meat quality in Jinhua and Landrace pigs. These results may provide valuable information for understanding the molecular mechanism responsible for breed specific differences in growth performance and meat quality.

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Amino acid digestibility and energy content of deoiled (solvent-extracted) corn distillers dried grains with solubles for swine and effects on growth performance and carcass characteristics

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A study with 3 experiments was conducted to determine the AA digestibility and energy concentration of deoiled (solvent-extracted) corn distillers dried grains with solubles (dDGS) and to evaluate its effect on nursery pig growth performance, finishing pig growth performance, and carcass traits. In Exp. 1, a total of 5 growing barrows (initial BW = 30.8 kg) were fitted with a T-cannula in the distal ileum and allotted to 1 of 2 treatments: 1) a diet with dDGS as the sole protein source, or 2) a N-free diet for determining basal endogenous AA losses in a crossover design at 68.0 kg of BW. Apparent and standardized (SID) ileal digestibility of AA and energy concentration of dDGS were determined. In Exp. 2, a total of 210 pigs (initial BW = 9.9 kg) were used in a 28-d experiment to evaluate the effect of dDGS on nursery pig performance. Pigs were allotted to 5 dietary treatments (0, 5, 10, 20, or 30% dDGS) formulated to contain equal ME (increased added fat with increasing dDGS) and SID Lys concentrations based on the values obtained from Exp. 1. In Exp. 3, a total of 1,215 pigs (initial BW = 29.6 kg) were used in a 99-d experiment to determine the effect of dDGS on growth and carcass characteristics of finishing pigs. Pigs were allotted to dietary treatments similar to those used in Exp. 2 and were fed in 4 phases. The analyzed chemical composition of dDGS in Exp. 1 was 35.6% CP, 5.29% ash, 4.6% fat, 18.4% ADF, and 39.5% NDF on a DM basis. Apparent ileal digestibility values of Lys, Met, and Thr in dDGS were 47.2, 79.4, and 64.1%, respectively, and SID values were 50.4, 80.4, and 68.9%, respectively. The determined GE and DE and the calculated ME and NE values of dDGS were 5,098, 3,100, 2,858, and 2,045 kcal/kg of DM, respectively. In Exp. 2, nursery pig ADG, ADFI, and G:F were similar among treatments. In Exp. 3, increasing dDGS reduced ADG and ADFI but tended to improve G:F. Carcass weight and yield were reduced, loin depth tended to decrease, and carcass fat iodine values increased as dDGS increased. No difference was observed in backfat, percentage of lean, or fat-free lean index among treatments. In conclusion, dDGS had greater CP and AA but less energy content than traditional distillers dried grains with solubles. In addition, when dietary fat was added to diets to offset the reduced ME content, feeding up to 30% dDGS did not affect the growth performance of nursery pigs but did negatively affect the ADG, ADFI, and carcass fat quality of finishing pigs.

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Metabolizable energy content of refined glycerin and its effects on growth performance and carcass and pork quality characteristics of finishing pigs

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Two studies were conducted with refined glycerin (97.7 and 97.5% glycerin for studies I and II, respectively) to determine ME content and effects on growth performance and carcass and pork quality measures of finishing pigs. An energy balance study using 24 barrows (21.5kg initial BW) determined the apparent ME content of glycerin using a generalized randomized block design with 2 dietary treatments: 1) control (99.85% corn + vitamins and minerals) and 2) glycerin (30% of corn in the control diet replaced with glycerin). A 7-d adaptation was followed by a 5-d collection period for feces and urine. The energy content of diets, feces, and urine was determined by bomb calorimetry. The DE of the glycerin diet was greater than that of the control diet (4,298 vs. 3,902 kcal/kg of DM); however, the ME content of the 2 diets was similar (3,820 vs. 3,723 kcal/kg of DM). The ME of refined glycerin (estimated by difference) was 3,584 kcal/ kg of DM. A growth study was conducted with 128 gilts housed in groups of 4 and reared from 92.5 kg of BW for a 28-d period, using a split-plot design with a 4 × 2 factorial arrangement of treatments: 1) dietary glycerin level (0, 5, 10, and 15%) and 2) preslaughter handling (gentle vs. intense). The handling treatment was included to simulate the range in handling intensities that are likely to be experienced in practice. At the end of the 28-d period, one-half of the pens on study were slaughtered and used for carcass and pork quality evaluation with 2 pigs from each pen being subjected to each of the preslaughter handling treatments. There were no interactions between dietary glycerin and preslaughter handling treatment. Dietary glycerin had no effect on growth performance, carcass measures, or meat quality. There were no differences between the gentle and intense handling treatments for carcass or pork quality measures. In conclusion, feeding glycerin to finishing pigs at up to 15% of the diet had no negative effect on growth performance or carcass and pork quality characteristics.

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Evaluation of glycerol, a biodiesel coproduct, in grow-finish pig diets to support growth and pork quality

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Crossbred pigs (n = 216; BW = 31.3kg) were used to determine the effects of long- and short-term feeding of crude glycerol on growth performance, carcass traits, and pork quality of grow-finish pigs. Pigs were blocked by initial BW, and pens within blocks were assigned randomly to 1 of 3 dietary treatments (24 pens; 9 pigs/pen). Dietary treatments were control, a corn-soybean meal-based diet (CON); longterm, CON + 8% glycerol fed throughout the experiment (LT); and short-term, pigs fed CON for the first 6 wk followed by CON + 8% glycerol fed during the last 8 wk of the experiment (ShT). Pigs fed LT had greater ADG, whereas pigs fed ShT tended to grow faster than CON (CON = 0.962 kg/d, LT = 0.996 kg/d, and ShT = 0.992 kg/d; SE = 0.01). Pigs assigned to LT had greater ADFI compared with CON, whereas ShT-fed pigs had similar ADFI to CON (CON = 2.78 kg/d, LT = 2.93 kg/d, and ShT = 2.86 kg/d; SE = 0.03). Gain:feed tended to be greater for CON- and ShT-fed pigs compared with LT-fed pigs (CON = 0.346, LT = 0.339, and ShT = 0.346; SE = 0.002). Hot carcass weight was greater for LT-fed pigs compared with CON, whereas ShT-fed pigs had HCW similar to both LT- and CONfed pigs (CON = 94.8 kg, LT = 97.5 kg, and ShT = 96.3 kg; SE = 0.90). Dressing percentage of CON-fed pigs was similar to both LT- and ShT-fed pigs, but LT-fed pigs tended to have greater dressing percentage than ShT-fed pigs (CON = 74.5%, LT = 74.9%, and ShT = 74.3%; SE = 0.16). Tenth-rib backfat and LM area were not affected by dietary treatment. There was a trend for LT-fed pigs to have a smaller fat-free lean percentage than CON-fed pigs (CON = 53.1%, LT = 52.26%, and ShT = 52.67%; SE = 0.25). Short-term glycerol feeding increased belly firmness compared with CON and had similar belly firmness compared with LT-fed pigs (CON = 29.46°, LT = 35.16°, and ST = 42.08°; SE = 3.07). Dietary treatment had no effect on pork quality of loins based on taste panel assessments. Feeding pigs 8% crude glycerol throughout the grow-finish period resulted in a 3% improvement in growth rate and a 2% depression in BW gain efficiency compared with CON diets. Grow-finish pigs fed diets containing 8% crude glycerol during the last 8 wk before slaughter achieved growth performance similar to pigs fed CON diets. Effects of crude glycerol on carcass traits seem to be limited to improvements in belly firmness with short-term feeding of glycerol.

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Effects of selection for decreased residual feed intake on composition and quality of fresh pork

Posted in: Meat Quality, Production by admin on August 4, 2011 | No Comments

The objectives of this study were to determine the extent to which selection for decreased residual feed intake (RFI) affects pork composition and quality. Pigs from the fifth generation of selection for decreased RFI (select) and a randomly selected line (control) were utilized. Two experiments were conducted. In Exp. 1, barrows (22.6 ± 3.9 kg) from select and control lines were paired based on age and BW. The test was conducted in 8 replicates of pairs for the test period of 6 wk. Calpastatin activity and myosin isoforms profile were determined on samples from the LM. Control barrows were heavier (59.1 vs. 55.0 kg) at the end of the test period. Calpastatin activity was greater in LM of select barrows than control barrows. In Exp. 2, composition and quality of gilts (114 kg) from control and select lines were determined. The model included fixed effects of line, slaughter date, melanocortin-4 receptor (MC4R) genotype, barn group, line × slaughter date, genotype × line interactions, a covariate of off-test BW, and sire, pen, and litter fitted as random effects. The select line (n = 80) had 0.043 kg less RFI per day than the control line (n = 89). Loin quality and composition were determined at 2 d postmortem. Desmin degradation was measured at 2 and 7 d postmortem. Purge, cook loss, sensory traits, and star probe texture were measured at 7 to 10 d postmortem on cooked chops. Residual correlations between RFI and composition and quality traits were calculated. Compared with the control line, carcasses from the select line tended to have less backfat, greater loin depth, and greater fat free lean. Loin chops from the select line had less intramuscular lipid content than loin chops from control line. Significant residual correlations between RFI and both tenderness (r = 0.24) and star probe (r = −0.26) were identified. Selection for decreased RFI has the potential to improve carcass composition with few effects on pH and water-holding capacity. However, decreased RFI could negatively affect tenderness and texture because of decreased lipid content and decreased postmortem protein degradation.

For more information the full article can be found at http://jas.fass.org/