Effect of probiotic-, bacteriophage-, or organic acid-supplemented feeds or fermented soybean meal on the growth performance, acute-phase response, and bacterial shedding of grower pigs challenged with Salmonella enterica serotype Typhimurium

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A 28-d experiment evaluated the growth performance, acute-phase response, and bacterial shedding patterns in pigs (n = 108; initially, 38.7 kg) fed 6 treatment diets, including a control diet with no antimicrobial agents (CON), a positive control diet containing chlortetracycline, 100 mg/kg (CT), a diet containing anti-Salmonella Typhimurium bacteriophage, 3 × 109 plaque-forming units/kg of feed (ASB), Lactobacillus plantarum CJLP56, 6.5 × 108 cfu/ kg of feed (LP), 0.2% microencapsulated organic acids (MOA), or 5% fermented soybean meal (FSM). Pigs were fed the diets for 2 wk before and 2 wk after challenging orally with Salmonella enterica serotype Typhimurium (SalT). Before bacterial challenge, ADFI was similar in all groups. After SalT challenge, ADFI of CON pigs was less than all other groups. Before challenge, pigs on MOA, FSM, and CT diets had greater ADG and G:F than CON pigs. After challenge (wk 3 to 4) and during the overall experimental period (wk 1 to 4), ADG of all treatment groups and G:F of all treatment groups except the LP group were greater than those of CON pigs. Relative to all other treatments, CON and LP pigs had greater bacterial shedding scores on d 7 after SalT challenge. At d 14 postchallenge, shedding scores declined in all treatment groups compared with CON pigs. Serum haptoglobin for all treatment groups increased from d 0 concentrations on d 6 postchallenge and declined to prechallenge concentrations on d 13. Circulating IGF-I concentrations declined from 2 to 6 d postchallenge and increased again by d 13 in ASB and LP groups, did not decline in FSM and CT groups, and continuously declined through d 13 in CON and LP groups. However, in MOA group, IGF-I concentrations declined from preinfection concentrations on d 2, increased on d 4, and declined again until d 13. The serum concentrations of the cytokines IL-6 and IL-1β were not generally affected by SalT challenge. In conclusion, acute infection of growing pigs with SalT was associated with short-term febrile responses in most pigs and reductions in ADFI and ADG of CON pigs. Compared with the CON diet, ASB, FSM, and MOA diets had a similar benefit to the antibiotic-supplemented diet in improving the performance of growing pigs, especially after bacterial challenge. However, further work needs to be done to better understand their mode of action in this class of pigs.

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Phosphorus digestibility and energy concentration of enzyme-treated and conventional soybean meal fed to weanling pigs

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Two experiments were conducted to determine the apparent total tract digestibility (ATTD) of P and the concentration of DE and ME in enzyme treated soybean meal (SBM) and in conventional soybean meal (SBM-CV). Phosphorus digestibility in 2 enzyme-treated SBM (HP-310 and HP-340) and in SBM-CV was measured using 36 barrows (initial BW: 21.9 kg) that were housed in metabolism cages and randomly allotted to 6 diets with 6 replicates per diet. During production, HP-310 had been treated with an enzyme mixture containing no phytase, whereas HP- 340 was treated with an enzyme mixture that contained exogenous phytase. Three diets containing HP-310, HP- 340, or SBM-CV as the sole source of P were formulated. Three additional diets also contained HP-310, HP-340, and SBM-CV, but each of these diets was fortified with 500 units of microbial phytase. The ATTD of P in HP- 310 and SBM-CV increased as phytase was included in the diet (from 59.8 to 77.7% for HP-310 and from 65.5 to 79.5% for SBM-CV), but the ATTD of P in HP-340 without and with phytase was not different (83.8 and 87.7%, respectively). There were no differences in the ATTD of P between HP-310 and SBM-CV, but the ATTD of P in HP-340 was greater than in the other 2 meals. The DE and ME in corn, 2 sources of enzyme-treated SBM (HP-200 and HP-310), and in SBM-CV were measured in the second experiment using 28 barrows housed in metabolism cages (initial BW: 16.8 kg of BW). The process used to produce HP-200 is similar to that used to produce HP-310 except that HP-200 is exposed to the enzymes for a shorter period of time than HP- 310. A corn-diet consisting of 96.45% corn and vitamins and minerals was formulated. Three additional diets were formulated by mixing corn and each source of SBM with vitamins and minerals. Pigs were randomly allotted to the 4 diets with 7 replicate pigs per diet, and urine and feces were collected quantitatively during the last 5 d of a 14-d feeding period. The concentration of DE in HP-200, HP-310, and SBM-CV was 4,333, 4,316, and 4,347 kcal/kg of DM, respectively. These values were not different, but they were greater than the DE in corn (3,891 kcal/kg of DM). The concentration of ME was 3,780, 3,926, 3,914, and 3,980 kcal/kg of DM in corn, HP-200, HP-310, and SBM-CV, respectively. These values were not different. It is concluded that enzyme treatment of SBM does not influence the digestibility of P or the concentration of DE and ME in the meals.

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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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A single nucleotide polymorphism set for paternal identification to reduce the costs of trait recording in commercial pig breeding

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In animal breeding, recording of correct pedigrees is essential to achieve genetic progress. Markers on DNA are useful to verify the on-farm pedigree records (parental verification) but can also be used to assign parents retrospectively (parental identification). This approach could reduce the costs of recording for traits with low incidence, such as those related to diseases or mortality. In this study, SNP were used to assign the true sires of 368 purebred animals from a Duroc-based sire line and 140 crossbred offspring from a commercial pig population. Some of the sires were closely related. There were 3 full sibs and 17 half sibs among the true fathers and 4 full sibs and 35 half sibs among all putative fathers. To define the number of SNP necessary, 5 SNP panels (40, 60, 80, 100, and 120 SNP) were assembled from the Illumina PorcineSNP60 Beadchip (Illumina, San Diego, CA) base on minor allele frequency (>0.3), high genotyping call rate (≥90%), and equal spacing across the genome. For paternal identification considering only the 66 true sires in the data set, 60 SNP resulted in 100% correct assignment of the sire. By including additional putative sires (n = 304), 80 SNP were sufficient for 100% correct assignment of the sire. The following criteria were derived to identify the correct sire for the current data set: the logarithm of odds (LOD) score for assigning the correct sire was ≥5, the number of mismatches was ≤1, and the difference in the LOD score between the first and the second most likely sire was >5. If the correct sire was not present among all putative sires, the mean LOD for the most likely sire was close to zero or negative when using 100 SNP. More SNP would be needed for paternal identification if the number of putative sires increased and the degree of relatedness was greater than in the data set used here. The threshold for the number of mismatches can be adjusted according to the practical situation to account for the tradeoff between false negatives and false positives. The latter can be avoided efficiently, ensuring that the correct father is being sampled. Nevertheless, a restriction on the number of putative sires is advisable to reduce the risk of assigning close relatives.

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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.

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

The site of intestinal disappearance of dl-methionine and methionine hydroxy analog differs in pigs

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A study was conducted with pigs to determine the sites of and the influence of dietary wheat middlings (WM) as a fiber source on the absorption of dl-Met (DLM) and dl-2-hydroxy-4-methylthio butanoic acid (HMTBA). Twelve 25-kg barrows were used in a replicated 6 × 4 incomplete Latin-square design with 6 diets and 4 periods per pig. Each pig was surgically fitted with simple T-cannulas in the terminal duodenum and ileum 2 wk before the initiation of the experiment and housed in a stainless-steel metabolism crate. The 6 diets were arranged in a 2 × 3 factorial of WM at 0 (CON) or 8% and Met source including none, DLM, or HMTBA. Supplemental DLM doubled the duodenal free Met concentration from 9.6 to 19.6 g/100 g of DMI. Supplemental DLM also increased the apparent ileal digestibility (AID) of free Met from 52 to 92%. Adding 8% WM increased duodenal NDF concentrations by 2 g/100 g of DMI and decreased AID of free Met. No HMTBA was detected in digesta collected from the duodenum or ileum of pigs fed the CON + HMTBA or the WM + HMTBA diets, indicating complete absorption before the terminal duodenum regardless of WM inclusion. Interactions between Met supplementation and WM were observed for the digestibility of all other nutrients. Fiber and AA digestibility in the ileum were the greatest for the CON + HMTBA diet, and least for the WM + HMTBA diet. The CON + HMTBA diet had greater AID of ADF, NDF, CP, and Thr, and greater AID of ADF, NDF, ash, Arg, Ile, Gly, and Pro when compared with the CON and CON + DLM diets, respectively. The WM + HMTBA had less AID of ADF, CP, and all AA with the exception of Lys, Trp, and Val when compared with the CON + HMTBA. In summary, absorption of HMTBA in the pig is complete by the end of the duodenum, but negative interaction between HMTBA and WM can decrease the AID of most AA.

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Effect of prenatal stress on subsequent response to mixing stress and a lipopolysaccharide challenge in pigs

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Sows subjected to prenatal stress have been found to produce offspring that have altered responses to stress. Our objective was to determine if exposing a sow to stress would alter the response of the offspring to lipopolysaccharide (LPS) at 2 mo of age or their response to mixing stress at 4 mo of age. Sow treatments consisted of intravenous injections of ACTH (1 IU/kg of BW), exposure to rough handling for a 10- min duration (rough), or no treatment (control) once per week from d 42 to 77 of gestation. At 2 mo of age, pigs from each treatment, 1 per litter (n = 21, 17, and 15 for the ACTH, rough, and control treatments, respectively), were challenged with 2 μg of LPS/kg of BW or saline, or served as a noninjected control. Their behavioral response to a human approach test and salivary cortisol were measured. At 4 mo of age, 1 pig from each treatment (n = 14, 14, and 15 for the ACTH, rough, and control treatments, respectively) was taken from its home pen and placed in a pen of unfamiliar pigs. At this time, a punch biopsy wound (6 × 6 mm) was created to measure the ability of the pig to heal the wound. At this same time, each pig received a 1-mL intramuscular injection of 20% ovine red blood cells (oRBC), and then a second injection of oRBC at 21 d postmixing. Blood samples were collected 3 times per week for 2 wk and then once a week for 4 more weeks. Blood samples were analyzed for cortisol, porcine corticosteroid- binding globulin, antibody response to oRBC, and nitric oxide production by macrophages. Behavior was recorded during the first 5 d after mixing. All pigs in the LPS challenge responded with characteristic sickness behavior; however, pigs in the rough treatment showed less sickness behavior than those in the other 2 treatments. Maternal stress treatment did not affect salivary cortisol. Pigs from all treatments responded similarly to mixing stress with regard to cortisol, porcine corticosteroid-binding globulin, antibody titers, nitric oxide production, and hematology measures, and all pigs experienced the same amount of aggression in response to mixing. Without altering peripheral measures of stress responsivity, prenatal stress enhanced the ability of pigs to cope with a simulated immune challenge, which could prove to be an adaptation to challenging environments.

The threonine requirement of sows increases in late gestation

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Current AA recommendations for sows are to provide a fixed amount of AA intake throughout gestation based on the assumption that there is a constant demand for AA; however, the demand for nutrients changes from maternal lean tissue in early gestation to fetal and mammary growth in late gestation. The objective of this study was to determine the Thr requirement in early (d 35 to 53 and 25 to 55 for Exp. 1 and 2, respectively) and late (d 92 to 110 and 81 to 111 for Exp. 1 and 2, respectively) gestation using the indicator AA oxidation (IAAO) method with l-[1-13C]Phe as the tracer AA. A total of 14 multiparous sows were used: 6 in Exp. 1 and 8 in Exp. 2. Each sow received each of 6 diets in random order in both early and late gestation. A basal diet was formulated to contain Thr at 60% of the 1998 NRC recommendation in Exp. 1 and 20 and 60% of the 1998 NRC in Exp. 2 for early and late gestation, respectively. Crystalline l-Thr was added to create additional diets with approximately 10% incremental increases in Thr. Sows were placed in respiration chambers, and expired air and blood were collected every 30 min for 5.5 h. Tracer Phe [mg/(kg of BW・h)] was given orally over the last 4 h divided into eight 0.5-h meals. Expired air and plasma were measured for 13CO2 enrichment and free Thr concentration, respectively. Background 13CO2 was subtracted from plateau 13CO2 enrichment. Data were analyzed using a 2-phase nonlinear Mixed model. The overall litter size and litter weight were 13.5 and 20.5 kg, respectively. Based on IAAO, the Thr requirement in early gestation was 6.1 g/d (R2 = 0.59, Exp. 1) and 5.0 g/d (R2 = 0.71, Exp. 2). In late gestation, the Thr requirement based on IAAO was 13.6 g/d (R2 = 0.60, Exp. 1) and 12.3 g/d (R2 = 0.58, Exp. 2). Based on plasma Thr, the Thr requirement in early gestation was 7.0 g/d (R2 = 0.90, Exp. 1) and 3.9 g/d (R2 = 0.90, Exp. 2). In late gestation, the Thr requirement based on plasma Thr was 10.5 g/d (R2 = 0.67, Exp. 2). There was a linear response to increasing Thr intake in late gestation in Exp. 1. Feeding a single amount of AA throughout gestation results in overfeeding AA in early gestation and underfeeding AA in late gestation. The 2-fold increase in Thr requirement in the last third of gestation suggests that phase feeding sows in gestation will more closely meet the demands for nutrients and that the requirement for essential AA in gestating sows should be re-evaluated in early and late gestation separately.

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Effects of tryptophan supplementation on aggression among group-housed gestating sows

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The objective of this study was to determine the effects of dietary Trp supplementation on mixing-induced aggression and the associated stress, and on reproductive performance in gestating sows. After weaning, sows were mixed in pens with electronic sow feeders on concrete-slatted floors. Each pen housed 21 sows, with approximately 2.7m2/sow of floor space allowance. Multiparous sows (n = 168) from 8 breeding groups were used, with 4 groups assigned to a control diet and 4 groups assigned to a high-Trp diet. Control sows received corn- and soybean meal-based diets throughout gestation (0.15% Trp) and lactation (0.21% Trp). Three days before and after mixing, sows assigned to the high-Trp treatment received approximately 2.3 times the dietary Trp (0.35% in the gestation diet and 0.48% in the lactation diet) fed to control sows. Six focal sows (2 sows from each of parity 1, 2, and 3 or greater) in each pen were designated and videotaped for 72 h after mixing to determine the type and number of aggressive interactions among sows. Before and 48 h after mixing, saliva samples were collected from focal sows, and scratches were assessed on all sows. Data were analyzed using the FREQ and GLIMMIX procedures (SAS Inst. Inc., Cary, NC). Aggression among sows was intense during the initial 6 h and decreased between 6 and 72 h after mixing. The initial aggression caused scratches and increased cortisol concentrations. Mature sows tended to fight for longer periods (112 vs. 52 s/h per sow) but had fewer scratches caused by aggression (injury score = 4.3 vs. 6.5) than parity-1 sows. Supplementation of dietary Trp reduced the total duration of head-to-head knocking but did not affect other aggressive behaviors. There was no difference between dietary treatments in injury scores or saliva cortisol concentrations. Sows in the high-Trp treatment had more total piglets born (12.5 vs. 10.5 pigs/litter) and more stillborn piglets (1.5 vs. 0.8 pigs/litter), but had no significant change in piglets born alive (10.8 vs. 9.7 pigs/litter) compared with control sows. The results indicate that the initial aggression after mixing caused more injuries in young sows than in mature sows. Supplementation of dietary Trp at 2.3 times the control amount for a short period did not effectively reduce aggression and the associated stress in sows at mixing.

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