Mospd1, a new player in mesenchymal versus epidermal cell differentiation.

Mospd1 codes for a small protein with unknown physiological function, which is part of a family of genes, including Mospd2 and Mospd3, defined by the presence of the major sperm protein domain and two transmembrane domains. This work characterizes the Mospd1 gene, the intracellular location of the protein and its expression in different mouse tissues and mesenchymal cell lines during differentiation. The role of Mospd1 in mesenchymal cellular differentiation was studied by siRNA knockdown experiments in mouse osteoblastic MC3T3-E1 cells. Transfection experiments of the targeted cDNA show MOSPD1 located in the endoplasmatic reticulum and in the Golgi apparatus. Removal of the last exon of the gene resulted in localization of the protein in the nucleus, which was attributed to a nuclear export sequence in the N-terminal part. In mouse tissues the gene was generally strongly expressed while mesenchymal tissues showed the highest expression. In mesenchymal cell lines Mospd1 mRNA was higher expressed in cells with advanced differentiation status. In osteoblastic, myoblastic, and adipocytic cell lines Mospd1 was up-regulated during differentiation. Genome-wide gene expression analysis after knockdown of Mospd1 by siRNA in MC3T3-E1 cells revealed a shift in the gene expression pattern from mesenchymal to epithelial genes featuring up-regulation of the epithelial cadherin Cdh1 and down-regulation of its inhibitors Snail1 and 2 and the mesenchymal cadherin Cdh11, suggesting a mesenchymal to epithelial transition. From these data we conclude that Mospd1 plays a pivotal role in the developmental regulation at the switch between mesenchymal and epithelial cells.

Microcomputed analysis of nerve angioarchitecture after combined stem cell delivery and surgical angiogenesis to nerve allograft.

INTRODUCTION: A detailed three-dimensional (3D) evaluation of microvasculature is evolving to be a powerful tool, providing mechanistic understanding of angiomodulating strategies. The aim of this study was to evaluate the microvascular architecture of nerve allografts after combined stem cell delivery and surgical angiogenesis in a rat sciatic nerve defect model. MATERIALS AND METHODS: In 25 Lewis rats, sciatic nerve gaps were repaired with (i) autografts, (ii) allografts, (iii) allografts wrapped in a pedicled superficial inferior epigastric artery fascia (SIEF) flap to provide surgical angiogenesis, combined with (iv) undifferentiated mesenchymal stem cells (MSC) and (v) MSCs differentiated into Schwann cell-like cells. At two weeks, vascular volume was measured using microcomputed tomography, and percentage and volume of vessels at different diameters were evaluated and compared with controls. RESULTS: The vascular volume was significantly greatest in allografts treated with undifferentiated MSCs and surgical angiogenesis combined as compared to all experimental groups (P<0.01 as compared to autografts, P<0.0001 to allografts, and P<0.05 to SIEF and SIEF combined with differentiated MSCs, respectively). Volume and diameters of vessel segments in nerve allografts were enhanced by surgical angiogenesis. These distributions were further improved when surgical angiogenesis was combined with stem cells, with greatest increase found when combined with undifferentiated MSCs. CONCLUSIONS: The interaction between vascularity and stem cells remains complex, however, this study provides some insight into its synergistic mechanisms. The combination of surgical angiogenesis with undifferentiated MSCs specifically, results in the greatest increase in revascularization, size of vessels, and stimulation of vessels to reach the middle longitudinal third of the nerve allograft.

T3 affects expression of collagen I and collagen cross-linking in bone cell cultures.

Thyroid hormones (T3,T4) have a broad range of effects on bone, however, its role in determining the quality of bone matrix is poorly understood. In-vitro, the immortalized mouse osteoblast-like cell line MC3T3-E1 forms a tissue like structure, consisting of several cell layers, whose formation is affected by T3 significantly. In this culture system, we investigated the effects of T3 on cell multiplication, collagen synthesis, expression of genes related to the collagen cross-linking process and on the formation of cross-links. T3 compared to controls modulated cell multiplication, up-regulated collagen synthesis time and dose dependently, and stimulated protein synthesis. T3 increased mRNA expressions of procollagen-lysine-1,2-oxoglutarate 5-dioxygenase 2 (Plod2) and of lysyloxidase (Lox), both genes involved in post-translational modification of collagen. Moreover, it stimulated mRNA expression of bone morphogenetic protein 1 (Bmp1), the processing enzyme of the lysyloxidase-precursor and of procollagen. An increase in the collagen cross-link-ratio Pyr/deDHLNL indicates, that T3 modulated cross-link maturation in the MC3T3-E1 culture system. These results demonstrate that T3 directly regulates collagen synthesis and collagen cross-linking by up-regulating gene expression of the specific cross-link related enzymes, and underlines the importance of a well-balanced concentration of thyroid hormones for maintenance of bone quality.

Chlortetracycline and tylosin runoff from soils treated with antimicrobial containing manure.

This study assessed the runoff potential of tylosin and chlortetracycline (CTC) from soils treated with manure from swine fed rations containing the highest labeled rate of each chemical. Slurry manures from the swine contained either CTC at 108 microg/g or tylosin at 0.3 microg/g. These manures were surface applied to clay loam, silty clay loam, and silt loam soils at a rate of 0.22 Mg/ha. In one trial, tylosin was applied directly to the soil surface to examine runoff potential of water and chemical when manure was not present. Water was applied using a sprinkler infiltrometer 24-hr after manure application with runoff collected incrementally every 5 min for about 45 min. A biofilm crust formed on all manure-treated surfaces and infiltration was impeded with > 70% of the applied water collected as runoff. The total amount of CTC collected ranged from 0.9 to 3.5% of the amount applied whereas tylosin ranged from 8.4 to 12%. These data indicate that if surface-applied manure contains antimicrobials, runoff could lead to offsite contamination.

Molecular phylogeny and population structure of the codling moth (Cydia pomonella) in Central Europe: II. AFLP analysis reflects human-aided local adaptation of a global pest species.

Originally resident in southeastern Europe, the codling moth (Cydia pomonella L.) (Tortricidae) has achieved a nearly global distribution, being one of the most successful pest insect species known today. As shown in our accompanying study, mitochondrial genetic markers suggest a Pleistocenic splitting of Cydia pomonella into two refugial clades which came into secondary contact after de-glaciation. The actual distribution pattern shows, however, that Central European codling moths have experienced a geographic splitting into many strains and locally adapted populations, which is not reflected by their mitochondrial haplotype distribution. We therefore have applied, in addition to mitochondrial markers, an approach with a higher resolution potential at the population level, based on the analysis of amplification fragment length polymorphisms (AFLPs). As shown in the present study, AFLP markers elucidate the genetic structure of codling moth strains and populations from different Central European apple orchard sites. While individual genetic diversity within codling moth strains and populations was small, a high degree of genetic differentiation was observed between the analyzed strains and populations, even at a small geographic scale. One of the main factors contributing to local differentiation may be limited gene flow among adjacent codling moth populations. In addition, microclimatic, ecological, and geographic constraints also may favour the splitting of Cydia pomonella into many local populations. Lastly, codling moths in Central European fruit orchards may experience considerable selective pressure due to pest control activities. As a consequence of all these selective forces, today in Central Europe we see a patchy distribution of many locally adapted codling moth populations, each of them having its own genetic fingerprint. Because of the complete absence of any correlation between insecticide resistance and geographic or genetic distances among populations, AFLP markers do not have a prognostic value for predicting an outbreak of pesticide resistance in the field. By combining mitochondrial genetic data and AFLP analysis it was possible, however, to track the recent evolutionary history of Cydia pomonella on three different time scales: from population splitting in Pleistocene, to interbreeding of mitochondrial haplotypes in Holocene, to human-aided complete intermixing and splitting into many locally adapted populations in very recent times. The case of Cydia pomonella is reminiscent of examples of sympatric speciation and another example of a human-induced globally successful pest species.

Molecular phylogeny and population structure of the codling moth (Cydia pomonella) in Central Europe: I. Ancient clade splitting revealed by mitochondrial haplotype markers.

The codling moth (Cydia pomonella L., Tortricidae, Lepidoptera) is an important pest of pome fruit with global distribution. It has adapted successfully to different habitats by forming various ecotypes and populations, often termed strains, which differ among each other in several morphological, developmental, and physiological features. Many strains of Cydia pomonella have developed resistance against a broad range of chemically different pesticides. Obviously, pesticide-resistant strains must have a genetic basis inherent to the gene pool of codling moth populations, and this deserves our particular attention. The primary intention of the present study was to contribute novel information regarding the evolutionary phylogeny and phylogeography of codling moth populations in Central Europe. In addition, we aimed at testing the hypothesis that differential biological traits and response patterns towards pesticides in codling moth populations may be reflected at a mitochondrial DNA level. In particular, we wanted to test if pesticide resistance in codling moths is associated repeatedly and independently with more than one mitochondrial haplotype. To this end, we analyzed mitochondrial DNA and constructed phylogenetic trees based on three mitochondrial genes: cytochrome oxidase I (COI), the A+T-rich region of the control region (CR), and the nicotinamide adenine dinucleotide dehydrogenase subunit 5 (ND5). The results indicate that Central European populations of Cydia pomonella are clearly divided in two ancient clades. As shown by means of a molecular clock approach, the splitting of the two clades can be dated to a time period between the lower and middle Pleistocene, about 1.29-0.20 million years ago. It is assumed that the cyclic changes of warm and cold periods during Pleistocene may have lead to the geographic separation of codling moth populations due to glaciation, giving rise to the formation of the two separate refugial clades, as already shown for many other European animal species. Due to their inclination towards developing novel detoxification gene variants, codling moth individuals from both clades independently and multifariously may have developed pesticide resistance, and this process may be ongoing. During their more recent evolutionary history, natural events such as the gradual disappearance of climate-specific geographic barriers, as well as human-aided dispersal in recent historic times, may have allowed codling moth haplotypes from the original clades to interbreed and completely merge again, creating a globally successful insect species with a gene pool capable of responding to novel selective challenges by rapid adaptation.

Inducible disruption of the c-myb gene allows allogeneic bone marrow transplantation without irradiation.

Allogeneic bone marrow (BM) transplantation enables the in vivo functional assessment of hematopoietic cells. As pre-conditioning, ionizing radiation is commonly applied to induce BM depletion, however, it exerts adverse effects on the animal and can limit experimental outcome. Here, we provide an alternative method that harnesses conditional gene deletion to ablate c-myb and thereby deplete BM cells, hence allowing BM substitution without other pre-conditioning. The protocol results in a high level of blood chimerism after allogeneic BM transplantation, whereas immune cells in peripheral tissues such as resident macrophages are not replaced. Further, mice featuring a low chimerism after initial transplantation can undergo a second induction cycle for efficient deletion of residual BM cells without the necessity to re-apply donor cells. In summary, we present an effective c-myb-dependent genetic technique to generate BM chimeras in the absence of irradiation or other methods for pre-conditioning.

Author Correction: Yolk sac macrophage progenitors traffic to the embryo during defined stages of development.

This article contains errors in Figs. 5 and 6, for which we apologize. In Fig. 5f, the image 'E12.5 tail' was inadvertently replaced with a duplicate of the image 'E12.5 trunk' from the same panel. In Figure 6d, the image 'E9.5/OH-TAM E8.5, embryo' was inadvertently replaced with a duplicate of the image 'E10.5/ OH-TAM E8.5, embryo' from Fig. 6b. The corrected versions of these figures appear in the Author Correction associated with this Article.

Yolk sac macrophage progenitors traffic to the embryo during defined stages of development.

Tissue macrophages in many adult organs originate from yolk sac (YS) progenitors, which invade the developing embryo and persist by means of local self-renewal. However, the route and characteristics of YS macrophage trafficking during embryogenesis are incompletely understood. Here we show the early migration dynamics of YS-derived macrophage progenitors in vivo using fate mapping and intravital microscopy. From embryonic day 8.5 (E8.5) CX3CR1+ pre-macrophages are present in the mouse YS where they rapidly proliferate and gain access to the bloodstream to migrate towards the embryo. Trafficking of pre-macrophages and their progenitors from the YS to tissues peaks around E10.5, dramatically decreases towards E12.5 and is no longer evident from E14.5 onwards. Thus, YS progenitors use the vascular system during a restricted time window of embryogenesis to invade the growing fetus. These findings close an important gap in our understanding of the development of the innate immune system.

Influence of sodium diethyldithiocarbamate (Imuthiol) on lymphocyte function and growth in weanling pigs.

Mitogen-stimulated lymphocyte proliferation, delayed-type hypersensitivity (DTH) reactions, interleukin-2 (IL-2) production, and growth performance were evaluated in 3-week-old pigs treated with imuthiol. Lymphocyte proliferative responses to Con A and PWM were reduced (P less than 0.05) in pigs treated with imuthiol at 25 mg/kg; PHA proliferative responses were not influenced by imuthiol treatment. Imuthiol at 2.5 mg/kg lowered IL-2 production when compared to saline-treated controls. Delayed-type hypersensitivity responses to PHA were higher in 25 mg/kg imuthiol-treated pigs; however, 2.5 mg/kg imuthiol-treated pigs had lower DHT reactions. Imuthiol at 2.5 mg/kg and 25 mg/kg reduced (P less than 0.05) average daily feed intake. These data suggest that in vivo imuthiol treatment in pigs lowers lymphocyte proliferative responses, IL-2 production, and growth performance.

Activated porcine alveolar macrophages: are biological response modifiers the answer?

We report that 75% of conventionally housed 3- to 4-week-old swine already have detectable activated alveolar macrophages as measured by cytotoxicity of tumor cells. These macrophages can not be further activated by the biological response modifier N-acetylmuramyl-L-alanyl-Disoglutamine-2H2O (MDP). These macrophages lose cytotoxic activity when cultured for 24 h and this loss of activity can not be reversed by MDP. We suggest that MDP biological response modifier therapy of swine alveolar macrophages may not be a useful technique in preventing respiratory disease in swine.

Osseous autografts. II. Histological responses to osseous coagulum-bone blend grafts.

Three human intraosseous lesions were treated using osseous coagulum-bone blend as graft material. These sites were surgically removed 6 to 13 weeks after treatment and the blocks prepared for histologic analysis. Periodontal remodeling at the site of grafting was noted in all specimens. This remodeling involved the osseous walls, periodontal ligament, cementum and graft spicules. Both osteoclastic and osteoblastic activities were seen at the borders of the spicules. Exfoliation of spicules was particularly frequent in the six-week specimen. Nevertheless, regenerating of both bone and cementum was actively taking place even in this early specimen and was still evident in the older specimens. Of particular interest was the apparent marked increase in cementogenesis at the graft sites and the variations in parallel or functional orientation of the periodontal ligament in these areas. Significant functional orientation of segments of the periodontal ligament were seenin the early specimens, but not in the latter one. The reason for such variations in ligament pattern is not known at this time.

Osseous autografts. I. Clinical responses to bone blend or hip marrow grafts.

A clinical evaluation was undertaken to compare regeneration of osseous defects following implantation of either osseous coagulum-bone blend from intraoral sources or autogenous iliac marrow-cancellous bone. Thirty-two transplants were performed in 15 male patients. The intraosseous defects in which marrow was placed (initial average depth = 7.18 mm) filled 60.7% (average fill = 4.36 mm). Defects in which osseous coagulum-bone blend was placed (initial average depth 4.0 mm) filled 73% (average fill = 2.93 mm). The difference in results between the two materials was not statistically significant. Therefore, similar levels of osseous regeneration apparently took place regardless of graft material used.

Osseous autografts. III. Comparison of osseous coagulum-bone blend implants with open curetage.

A clinical investigation was undertaken to compare regeneration of osseous defects following either osseous coagulum-bone blend grafts or open debridement procedures. Seventy-five sites in 28 patients were treated by the two procedures. The average fill in the 37 intraosseous defects treated by graft procedures (initial average depth = 4.22 mm, S.D. 1.73) was 2.98 mm, S.D. 1.44. The average fill in the 38 intraosseous lesions treated by open debridement procedure (initial average depth = 3.03 mm, S.D.0.80) was 0.66 mm, S.D. 0.80. Statistical analysis showed a significant difference (P greater than 0.01) in fill patterns between the bone blend and open debridement responses in favor of graft treated sites. Therefore greater levels of osseous regeneration apparently took place in our cases following osseous coagulum-bone blend autogenous graft procedures than following open debridement procedures in all types of defects studies.

Effect of wean-to-finish management on pig performance.

In each of three trials, 240 crossbred barrows weaned at 17 d of age (5.1 kg BW) were assigned to one of three experimental treatments based on light and heavy weight outcome groups. Experimental treatments were 1) wean-to-finish at 0.69 m2/pig and 15 pigs/pen; 2) wean-to-finish double-stocked at 0.35 m2/pig, 30 pigs per pen for 8 wk and then randomly split into two pens (either stayed in same pen or moved to new pen) for growth to slaughter at 0.69 m2/pig; and 3) nursery facility for 8 wk at 0.35 m2/pig and 15 pigs/pen followed by move to the same grow-finish facility housing wean-to-finish and double-stocked pigs and maintaining pen integrity. Beginning at 38 kg BW, diets were supplemented with either bacitracin methylenedisalicylate at 33 mg/kg to slaughter or tylosin at 44 mg/kg to 59 kg BW and 22 mg/kg thereafter. There were no trial x treatment interactions, even though there was considerable variation in health status among trials. At the end of the 56-d nursery period, wean-to-finish pigs weighed more than nursery (28.7 vs 27.7 kg; P = 0.071) and double-stocked pigs (28.7 vs 26.9 kg; P = 0.002), due to greater ADG (wean-to-finish vs nursery; P = 0.062; wean-to-finish vs double-stocked; P = 0.002) and greater ADFI (wean-to-finish vs nursery; P = 0.024; wean-to-finish vs double-stocked, P = 0.002). There was no effect of treatments (P > 0.1) on ADG, feed conversion, carcass lean percentage, or lean gain during the growing-finishing period. There was also no effect of treatment (P > 0.1) on ADG or ADFI from weaning to slaughter. There was no difference (P > 0.1) between bacitracin methylenedisalicylate and tylosin for ADG, feed conversion, carcass lean percentage, or daily lean gain. These data suggest that housing 5-kg weaned pigs in fully slatted growing-finishing facilities from weaning to slaughter was not detrimental to overall performance. In this experiment, dietary additions of bacitracin methylenedisalicylate or tylosin from 38 kg BW to slaughter weight resulted in similar growth performance.

Effect of dietary folic acid supplementation on sow performance through two parities.

One hundred fifty-three gilts were maintained in three breeding groups and fed gestation-lactation diets supplemented with either 0 (control), 1.65 or 6.62 mg of supplemental folic acid/kg of diet for two consecutive parities. Serum folate concentrations of sows were linearly (P less than .05) increased by dietary additions of folic acid during both gestation and lactation, but serum glucose and urea concentrations were unaffected by treatment. Serum folate concentrations decreased from breeding to d 60 and 90 of gestation and then increased through lactation for all treatments. Number of pigs born and live pigs at birth, d 14 and d 21 were quadratically (P less than .05) increased by folic acid additions. Average pig weights were similar among treatments (P greater than .10) on both d 0 and 14 of lactation but were less (P less than .01) than the other treatment groups on d 21 for pigs from sows fed the 1.65 mg/kg treatment. Litter weights were quadratically (P less than .01) increased on d 0 and d 14 by folic acid supplementation. Sow weight gain and backfat thickness loss were unaffected by treatment during gestation (P greater than .06); sow weight loss and backfat thickness loss increased quadratically with increasing level of folic acid during lactation (P less than .06 and .05, respectively). More control sows exhibited estrus by d 7 postweaning than sows receiving folic acid supplementation in parity I (P less than .05); however, no differences (P greater than .10) were detected among treatments by d 14, nor were any differences observed by d 7 in parity II. Conception rate was unaffected by folic acid additions. Dietary folic acid supplementation improved sow reproductive performance by increasing the number of pigs born alive.

Effects of high-protein/low-carbohydrate swine diets during the final finishing phase on pork muscle quality.

The aim of this study was to lower the glycogen stores in pork muscle in order to improve pork muscle quality by feeding an ultra-high-protein/low-carbohydrate (HIPRO) diet. Forty-eight barrows (average live weight = 92 kg) were assigned across five treatments and two replications (four or five pigs per treatment by replication combination). All barrows were fed a control diet (13.1% CP) until their assigned treatment began. A treatment was the number of days the barrows were fed the HIPRO diet prior to slaughter (0, 2, 4, 7, or 14 d). The HIPRO diet (35.9% CP) was 97% extruded soybeans. Daily feed intake and weekly live weights were recorded for all barrows. At-death blood glucose levels were determined. Muscle pH, temperature, and electrical impedance were measured in the longissmus lumborum and semimembranosus muscles at 45 min, 3 h, and 24 h postmortem. Glycolytic potential; Minolta L*a*b* values; visual scores for color, firmness, and marbling; water-holding capacity traits (drip loss, purge loss, and cooking loss); and Warner-Bratzler shear force values were determined in the longissmus thoracis et lumborum. Weight gain per day decreased the longer the pigs were fed the HIPRO diet (P < 0.05). Daily feed intake decreased during the 1st wk on the HIPRO diet but returned to near-control levels during the 2nd wk, which when coupled with the continued decreases in daily gain resulted in substantial decreases in feed efficiency during the 2nd wk on the HIPRO diet (P < 0.05). Blood glucose levels and glycolytic potentials were not lowered by feeding the HIPRO diet (P > 0.05); therefore, no differences in rate of pH decline or ultimate pH among dietary treatments were found (P > 0.05). Likewise, there were no differences among dietary treatments in any of the measured meat quality attributes (P > 0.05). Feeding barrows the HIPRO diet for a time period prior to slaughter decreased feed intake, rate of gain, and feed efficiency and was not effective at lowering glycolytic potential or improving pork muscle quality.

Interrelationships between porcine somatotropin and dietary lysine on growth performance and carcass characteristics of finishing swine.

Seventy-two barrows (initial weight = 57.1 kg) were used to determine the interrelationship between porcine somatotropin (pST) and dietary lysine and their effects on growth performance and carcass characteristics. Pigs were injected daily in the extensor muscle of the neck with either 4 or 8 mg of pST and fed a pelleted corn-soybean meal-sesame meal diet (.8% lysine; 17.8% CP) or diets containing 1.0, 1.2, or 1.4% lysine provided by additions of L-lysine.HCl (2 x 4 factorial arrangement). Control pigs (placebo injection) received the .8% lysine diet. All diets were formulated to contain > or = 200% of current recommendations for other amino acids, vitamins, and minerals. A tendency for a pST x lysine interaction was observed for cumulative ADG (P < .15) and feed conversion (G/F; P < .05). Average daily gain and G/F were improved by increasing dietary lysine level in pigs injected with 4 mg/d of pST; however, pigs injected with 8 mg/d of pST had greater improvements in cumulative ADG and G/F with added lysine. Feed intake was reduced (quadratic, P < .10) as dietary lysine level and pST dosage increased. Increasing pST dosage and dietary lysine increased (linear, P < .05) longissimus muscle area and decreased backfat thickness. Trimmed ham and loin weights were increased (linear, P < .10) by pST dosage. Chemical composition of samples taken from the loin, ham, and belly indicated increased moisture and CP and decreased lipid content as pST dosage and dietary lysine level increased (quadratic, P < .05). Shear force values from loin and semimembranosus increased with increasing lysine level (quadratic, P < .01) and pST dosage (linear, P < .05); however, these differences were not detected by sensory analysis (P > .20). Plasma urea concentrations on d 28 decreased with increasing lysine level (quadratic, P < .05), and plasma lysine concentrations increased (linear, P < .01). Based on the pST x lysine interaction for ADG and G/F, these data suggest that the lysine level needed to maximize growth performance and carcass characteristics may be proportional to the pST dosage provided. Growth and carcass characteristics were maximized by dietary lysine intakes of 27 to 32 and > or = 36 g/d for pigs injected with 4 and 8 of mg/d of pST, respectively.

Evaluation of a biological response modifier: effects on starter pig performance.

The influence of a biological response modifier (FK-565) on weanling pig performance was evaluated. One hundred twenty-five weanling pigs (weaned at 21 +/- 3 d) averaging 6.3 kg were utilized in a 35-d growth trial. Dietary treatments included a basal diet (1.25% lysine, corn-soybean meal-dried whey), the basal plus .1, 1 or 10 ppm FK-565 and the control plus an antibacterial combination containing chlortetracycline, sulfamethazine and penicillin. Performance was recorded weekly, and on d 35 all pigs were bled for whole blood and serum chemistry profiles and then were euthanatized. Heart, liver, kidneys and spleen weights were recorded. Also, gross and histological examinations were made of these organs, as well as sections of lung, ileum, bone marrow, thymus and mesenteric lymph node. By d 14, pigs fed the antibacterial diet gained faster (P less than .06) than pigs fed the control and FK-565 diets. However, no differences (P less than .10) in feed intake at d 14 or efficiency of feed utilization at either d 14 or 35 were observed. For the overall 35-d trial, ADG was greater (P less than .01) for pigs consuming the antibacterial diet than for pigs consuming control and the FK-565 diets. Pigs consumed more of the antibacterial diet than of the other diets (P less than .05).(ABSTRACT TRUNCATED AT 250 WORDS)

The effects of porcine somatotropin and dietary lysine on growth performance and carcass characteristics of finishing swine.

Seventy-two finishing pigs (initial weight = 57.6 kg) were utilized to determine the effects of porcine somatotropin (pST) and dietary lysine level on growth performance and carcass characteristics. Pigs were injected daily with 4 mg pST in the extensor muscle of the neck and fed either a pelleted corn-sesame meal diet (.6% lysine, 17.8% CP) or diets containing .8, 1.0, 1.2 or 1.4% lysine provided by additions of L-lysine.HCl. All diets were formulated to contain at least twice the required amounts of other amino acids. Control pigs received a placebo injection and the .6%-lysine diet. Increasing levels of dietary lysine resulted in increased ADG and improved feed conversion (quadratic, P less than .01) for pST-treated pigs. The calculated daily lysine intake was 16.6, 13.6, 19.6, 25.1, 29.6 and 33.6 g for the control and pST-treated pigs fed .6, .8, 1.0, 1.2 and 1.4% lysine, respectively, over the entire experiment. Breakpoint analysis indicated that cumulative ADG and feed conversion were optimized at 1.19 and 1.22% lysine, respectively. Longissimus muscle area and trimmed ham and loin weights increased as dietary lysine was increased among pST-treated pigs (quadratic, P less than .01). Breakpoint analysis indicated that 1.11% lysine maximized longissimus muscle area, whereas trimmed ham and loin weights were maximized at .91 and .98% lysine, respectively. Adjusted backfat thickness was not affected by dietary lysine, but pST-treated pigs had less backfat (P less than .05) than control pigs did. Percentage moisture of the longissimus muscle increased (linear, P less than .05), as did percentage CP (quadratic, P less than .05), whereas fat content decreased (linear, P less than .05) as lysine level increased. Similar trends in composition were observed for muscles of the ham (semimembranosus, semitendinosus, and biceps femoris). Shear-force values from the longissimus and semimembranosus were lowest for control pigs, but they increased as dietary lysine level increased among pST-treated pigs. Sensory panel evaluations indicated that juiciness and tenderness decreased (linear, P less than .05) as dietary lysine level increased. Plasma urea concentrations decreased linearly (P less than .01) on d 28 as lysine level increased, whereas plasma lysine and insulin were increased (quadratic, P less than .01). Plasma glucose and free fatty acid concentrations on d 28 tended to increase (quadratic, P less than .10) with increasing dietary lysine level.(ABSTRACT TRUNCATED AT 400 WORDS)