In vitro muscle cell proliferation and protein turnover as affected by serum from pigs fed antimicrobials

The effect of antimicrobial supplementation of pigs on the capacity of their sera to influence proliferation and protein turnover in cultured muscle cells was evaluated. Mitogenic activity of sera increased when pigs were fed ASP250 (P less than .005) or carbadox (P less than .001), whereas the mitogenic activity of serum from pigs receiving the basal diet remained unchanged (P = .5). Additionally, sera from ASP250-fed pigs significantly decreased (P less than .001) total cellular protein degradation compared with sera obtained from the same pigs prior to supplementation. Neither ASP250 nor carbadox stimulated proliferation of myogenic cells when added to the culture media. Inclusion of ASP250 in swine diets altered the composition of their sera in a way that stimulated muscle cell proliferation and reduced the rate of protein degradation in cultured myogenic cells. Likewise, the inclusion of carbadox in swine diets increased the ability of their sera to stimulate cultured muscle cell proliferation.     

Effect of sera from fed and fasted pigs on proliferation and protein turnover in cultured myogenic cells

The effects of fasting on the ability of swine serum to affect proliferation, protein synthesis and protein degradation in L6 myoblast cell culture bioassays were evaluated. Barrows (15 to 20 kg) were fitted with jugular catheters. Blood samples were collected at four evenly spaced intervals between 0800 and 1700 on collection days. Prefast blood samples were obtained on d 1 and 2 of the study, after which pigs were subjected to a 5-d fast. Fasted samples were obtained on the 1st, 3rd and 5th d of the fast (d 3, 5 and 7 of the study). Serum from each collection day was pooled and tested in the proliferation bioassay for each pig. Prefast and fasted serum pools were formed by pooling prefast days (1 and 2) or fasted days (3, 5 and 7), respectively, from all pigs in a study. These pools were tested in the proliferation and protein turnover bioassays as well as in a Somatomedin-C (SmC) radioimmunoassay. Serum from the fasted collection days showed a decrease in mitogenic activity compared with serum from the two prefast days (P less than .001). At high concentrations, sera obtained from fasted pigs inhibited muscle cell proliferation (P less than .001). Additionally, adding fasted serum to control swine serum (CSS) inhibited the mitogenic activity of CSS in a dose-dependent manner (P less than .025). Therefore, fasted sera showed a decreased ability to promote muscle cell proliferation and, in addition, appeared to contain a factor(s) that inhibits muscle cell proliferation. Fasted serum also caused a 21.6% increase in protein degradation compared with prefast serum.(ABSTRACT TRUNCATED AT 250 WORDS)     

Partial purification of a serum fraction from fasted pigs that inhibits proliferation of cultured myogenic cells

Sera from pigs fasted as little as 24 h appears to contain a factor(s) that inhibits proliferation of myogenic cells in culture. An inhibitor of myogenic cell proliferation has been partially purified from this sera by using a combination of gel filtration and immunoaffinity chromatography. The inhibitory activity elutes from a Sephacryl S-300 column at a Kav (elution minus void volume divided by total minus void column volume) between .41 and .59. Proteins banding at 76 and 67 kilodaltons appear to predominate on sodium dodecyl sulfate polyacrylamide gels of this fraction. Small quantities of each of these proteins were electrophoretically purified and used to elicit production of anti-76 and anti-67 immunoglobulin G in rabbits. These antibodies were used to prepare anti-76 and anti-67 column was particularly useful in isolating the inhibitor because it removed mitogens that made detection of the inhibitory activity difficult. The partially purified inhibitor inhibits proliferation of L6 myogenic cells in a concentration-dependent manner. On sodium dodecyl sulfate polyacrylamide gels, the predominant proteins in the inhibitor fraction band at approximately 63 and 61 kilodaltons. Inhibitors of myogenic cell proliferation may play an important role in balancing the effects of positive growth factors.     

Fetal hypophysectomy causes a decrease in preadipocyte growth and insulin like growth factor-1 in pigs

Fetal pigs in one uterine horn of each of five gilts were hypophysectomized (HX) in utero by electrical cauterization at 72-74 days of gestation and sera collected at 110 days of gestation. Sera from HX fetuses had lower levels of insulin-like growth factor-1 compared to control littermates (P less than .05). Sera were tested for their effects on primary cultures of stromal-vascular cells from adipose tissue. The soluble protein concentration/dish was lower when pig cells were cultured in sera from HX fetuses compared to sera from control fetuses (P less than .01). Sera from HX fetuses inadequately supported growth of stromal-vascular cells so subsequent experiments utilized pooled sera from normal and HX adult pigs. Sera from HX and control fetuses were mixed with sera from the two adult pools and tested for incorporation of tritiated thymidine into rat preadipocytes and the appearance of adipocytes (determined histochemically) in pig stromal-vascular cultures. In cultures fed sera from HX fetuses there was a lower (P less than .05) number of pig fat cells/culture and a lower level (P less than .06) of preadipocyte proliferation in rat cell cultures when compared to control fetal sera. Fetal pig serum contains factors (adipogenic) which promote the proliferation and differentiation of adipocytes in culture. Serum from HX fetuses has a lower level of adipogenic factors.     

Specificity of affinity-purified Trichinella spiralis antigens.

An affinity-purified fraction (APF) was obtained by passing crude somatic antigens of Trichinella spiralis muscle larvae through an Affi-Gel 10 column coupled with anti-Trichuris suis IgG. The fraction contained seven antigens with molecular weights ranging from 28 to 55 kDa. When tested with antiserum against other common nematodes of pigs from China, the APF was found to be markedly more specific than S3 antigens (prepared by a combination of cell fractionation and differential centrifugation according to Despommier and Lacetti, 1981) and fractions produced by Sephacryl S-200 gel filtration (F1 to F12). When the APF was used in an indirect IgG-enzyme-linked immunosorbent assay (IgG-ELISA) to screen serum samples from 2000 pigs imported from China, a positive rate of 7.5% was obtained. Similar screenings using the crude somatic antigens F1 and S3 gave a large number of cross-reactions and false positive reactions. Positive rates of 48%, 39% and 59.5% respectively were obtained for the three antigens.     

Association between serum cytotoxicity and selected clinical variables in 240 horses admitted to a veterinary hospital.

A total of 378 serum samples from 240 hospitalized horses and 47 sera from healthy control horses were assayed for growth effects on actinomycin D-treated L929 cells. On average, patient and control sera stimulated cell growth; however, mean percentage of the relative growth index (RGI) of sera from clinical cases was significantly (P less than 0.001) lower than that of control sera. Approximately 35% of patient sera and 6% of control sera had tumor necrosis factor-like cytotoxic activity for L929 cells (ie, RGI less than 100%). Sera from horses with either peritoneal leakage of gastrointestinal tract contents or any bacterial infection were significantly (P less than 0.05) more cytotoxic than sera from horses that did not have these clinical factors. A clear tendency was evident for horses that had the highest serum cytotoxicity (RGI less than 75%) to also have clinical profiles suggestive of endotoxemia. Fever, leukopenia, diarrhea, and gastrointestinal tract leakage were significantly (P less than 0.05) overrepresented among these horses, compared with horses without serum cytotoxicity. Bacterial infections and abdominal surgeries were also increased in this group, but not significantly. Of the 14 horses with serum RGI less than 75%, 13 had some form of gastrointestinal tract disease and the other had gram-negative septicemia. Survival to discharge was significantly (P less than 0.05) lower among horses in the high-cytotoxicity group than among horses without serum cytotoxicity. Diarrhea and bacterial infections were the only clinical factors found more frequently in horses with low serum cytotoxicity than in horses without serum cytotoxicity.(ABSTRACT TRUNCATED AT 250 WORDS)     

Field evaluation of the enzyme-linked immunosorbent assay for swine trichinosis: efficacy of the excretory-secretory antigen

A field evaluation of an enzyme-linked immunosorbent assay (ELISA) for swine trichinosis was done with sera obtained from 5 herds experiencing ongoing transmission of Trichinella spiralis. Epizootiologic studies conducted on these herds offered an opportunity to evaluate the accuracy of an ELISA, using larval T spiralis excretory-secretory antigens. Sera from 162 infected pigs and 143 serum samples from noninfected pigs originating from the same farms were tested. The infection status of the pigs was determined by digestion of diaphragm or tongue muscle samples. Two criteria were established to classify the ELISA optical density (OD) readings: Criterion I stated that an OD greater than or equal to 5 times the mean OD of several normal swine sera pools was positive; criterion II stated that a OD greater than or equal to 4 times the normal sera values was positive. The results obtained did not reveal obvious serologic variations among infected herds located in the 4 states involved. Overall, the test detected 93% (criterion I) and 96% (criterion II) of infected pigs. The majority of false-negative sera was from hogs that had less than 5 larvae/g of muscle; 1 hog had 73.8 larvae/g of diaphragm muscle. The false-positive rates were 8% for criterion I and 9% for criterion II. The actual rate for these false-positive samples may have been overestimated, because generally, only small tissue samples (0.4 to 10 g) were digested; larger sample sizes might have altered the results. The relevance of this qualification is that these pigs originated from herds with prevalence rates greater than 50%. Other factors that may account for occasional false-positive sera or false-negative sera in the swine trichinosis ELISA are discussed.(ABSTRACT TRUNCATED AT 250 WORDS)     

The effect of copper and fat addition to the diets of weanling swine on growth performance and serum fatty acids.

A 2 x 3 factorial experiment, encompassing three 28-d trials involving a total of 420 weanling pigs, was conducted to determine the effect of dietary Cu (5 or 250 ppm) and animal fat (0, 2.5, or 5%) on the performance and serum fatty acid profiles of weanling pigs. Pigs had ad libitum access to corn-soybean meal-based diets containing 10% whey and 5% fish meal and similar lysine:calorie ratios. Pigs were weighed and pen feed intakes were recorded weekly. Weekly blood samples were collected during the first two trials (n = 270) for serum fatty acid analysis. There was a Cu x fat interaction for ADG from d 1 to 14 (P less than .07) and over the 28-d experiment (P less than .05). The ADG of pigs fed 250 ppm of Cu increased, whereas the ADG of pigs fed 5 ppm of Cu was not affected as dietary fat increased. The addition of 250 ppm of CU increased (P less than .01) ADFI throughout the 28-d experiment. The addition of fat quadratically increased ADG (P less than .05) during d 14 to 28 and gain:feed ratios (P less than .01) during d 14 to 28 and over the 28-d experiment. The addition of fat decreased (P less than .05) the weight percentage of serum saturated fatty acids and increased (P less than .01) the weight percentage of serum monounsaturated fatty acids on d 28. The addition of 250 ppm of Cu decreased (P less than .01) the weight percentage of monounsaturated fatty acids on d 14 and 28.(ABSTRACT TRUNCATED AT 250 WORDS)     

Stimulation of in vitro muscle cell proliferation by sera from swine injected with porcine growth hormone

The proliferation-promoting activity of sera obtained from pigs before and after porcine growth hormone injections was tested in a muscle cell culture bioassay. For 3 d, purified porcine growth hormone (pGH) was administered by intramuscular injection to crossbred barrows. Two levels of pGH were administered: 18 micrograms pGH X kg-1 body weight X d-1 (low dose) or 143 micrograms pGH X kg-1 body weight X d-1 (high dose). Multiple blood samples were withdrawn from jugular catheters for 3 d prior to the injection, during the injection period and for 6 d after the last injection. Although serum pGH levels in low-dose pigs were raised from two to three times pre-injection levels, there was no significant change in serum proliferation-promoting activity or somatomedin-C (SmC), insulin or cortisol levels during or after administration of pGH. In contrast, the proliferation-promoting activity of sera obtained during and after the high-dose pGH injections was higher (P less than .005) than the pre-injection levels. Serum pGH levels were increased approximately 30-fold by 4 h after each injection, and increases in SmC levels were observed 10 to 16 h after the pGH injection. During the injection period SmC levels increased from 1.7 to 4 times pre-injection levels. Insulin and cortisol levels did not change significantly during the 3-d treatment period. We believe that this muscle cell culture bioassay system will be a useful addition to traditional radioimmunoassays and whole animal studies in elucidating the mode of action of pGH in pituitary-intact swine.     

Sera-controlled preadipocyte growth in culture: an ontogeny study with sera from lean and obese pigs

Genetically lean and obese swine were used to investigate the control of preadipocyte growth in culture by porcine serum. Sera were collected from fetuses from obese and lean strains at 70, 90 and 110 d of gestation. Postnatal serum samples were collected from both lines of pigs at 23 to 27 kg. Rat preadipocytes were isolated and grown in culture. Preadipocyte and stromal-vascular cell proliferation was greater in cultures grown in sera obtained postnatally than in cultures grown in sera from fetuses. Sera from lean and obese fetuses were equipotent in promoting cell proliferation. Glycerol-phosphate dehydrogenase (GPDH) activity was higher in cultures fed serum from obese pigs and fetuses than in cultures fed serum from lean pigs and fetuses. Cultures grown in serum from obese fetuses and pigs had soluble protein levels similar to cultures grown with serum from lean pigs and fetuses. These results demonstrate that serum from genetically obese swine, in the pre-obese (fetal) and obese (postnatal) state, caused increased adipogenic activity in adipocytes in culture.     

Interactive effects of sodium zeolite-A and copper in growing swine: growth, and bone and tissue mineral concentrations.

An experiment was conducted with 64 crossbred pigs to determine the effect of 0 or .50% dietary sodium zeolite-A (NZA) in combination with 0 or 250 ppm supplemental Cu (as CuSO4.5H2O). Pigs were assigned randomly to one of the following four treatments: 1) corn-soybean meal basal (B), 2) B + .50% NZA, 3) B + 250 ppm Cu, or 4) B + .50% NZA + 250 ppm Cu. Each treatment was replicated four times with four pigs per replicate. Average initial weight was 7.5 kg and the experimental period lasted 144 d. Overall rate and efficiency of gain, incidence of gastric ulcers, dressing percentage, carcass weight, percentage of muscling, 10th rib fat, loin eye area, blood urea N, and bone Ca, P, Mn, Fe, Ni, Na, and Al concentrations were not affected by treatment. The addition of 250 ppm Cu increased liver (P less than .01), serum (P less than .06), and bone (P less than .07) Cu concentrations but decreased mean backfat thickness (P less than .09), bone ash percentage (P less than .03) and serum (P less than .09) and bone (P less than .01) Zn concentrations. Sodium zeolite-A increased serum alkaline phosphatase (P less than .04), carcass length (P less than .06), and liver (P less than .02) and bone (P less than .01) Zn content but decreased (P less than .04) serum Ca and serum inorganic P concentrations. Sodium zeolite-A did not protect against liver Cu accumulation or gastric ulceration in growing swine fed 250 ppm supplemental Cu.     

Isolation of a 14 kDa antigen from Taenia solium cyst fluid by HPLC and its evaluation in enzyme linked immunosorbent assay for diagnosis of porcine cysticercosis

A fraction with a major band of 14kDa was obtained from crude cyst fluid of Taenia solium cysticerci by 2-step chromatography. A first fraction isolated by gel filtration (Sephacryl S-300 high resolution) was purified using an anion exchange column (Mono Q HR 5/5) on high performance liquid chromatography. Evaluation of the analytic sensitivity of this fraction (F3) was carried out in an antibody enzyme linked immunosorbent assay (Ab-ELISA-F3) using serum samples from pigs experimentally infected with different doses of T. solium eggs. The cross-reactivity of F3 was evaluated with serum samples from pigs that were naturally or experimentally infected with Taenia hydatigena, Taenia saginata asiatica, Fasciola hepatica, Trichinella spiralis, Metastrongylus apri, Trypanosoma congolense and Sarcoptes scabiei, and with serum samples of rabbits hyper-immunised with metacestode cyst fluid of T. hydatigena and T. solium. Antibody titres of lightly or heavily infected pigs differed in their kinetics. However, the increase in F3-specific antibodies could not be related to the infection level. Analysis of the specificity of the F3 showed that serum samples of pigs infected with other parasites did not recognise this antigen. Cross-reaction with T. hydatigena occurred in ELISA using cyst fluid as antigen, but the F3 antigen fraction was not recognized by rabbit hyper-immune serum samples to T. hydatigena. Evaluation of the diagnostic sensitivity and specificity of the Ab-ELISA-F3 was done by a non-parametric receiver operating characteristic (ROC) analysis using 66 serum samples from Zambian village pigs. The total number of cysticerci of these pigs was determined by dissection (28 pigs harboured T. solium cysticerci and 38 were negative at dissection). In addition, 58 serum samples from Cameroonian pigs (28 pigs from cysticercosis-free farms and 30 pigs with cysticerci at tongue inspection) were used in a separate ROC analysis. The results from the ROC analysis yielded a low diagnostic value (area under ROC curve=0.48) with the sera from the Zambian pigs while a relatively high diagnostic value was obtained with the sera from Cameroonian pigs (area under ROC curve=0.78). The main factor contributing to a low diagnostic value based on the Zambian serum samples seemed to be the false-positive reactions that were likely caused by the occurrence of transient antibodies in the non-infected animals.     

Growth performance and carcass characteristics of pigs administered recombinant porcine somatotropin during 30 to 110 kilogram live weight

To determine growth performance during and after injection of recombinant porcine somatotropin (rpSt), crossbred Yorkshire gilts and barrows (n = 54/gender, 27 to 42 kg BW) were blocked by BW and gender (n = 3 blocks/gender). Within each block, three pigs/gender were assigned randomly to each of six pens/block. A diet containing 24.8% CP was fed ad libitum. During the live weight period of 30 to 110 kg, pigs either remained as controls (one pen/block) or were injected (i.m.) daily with rpSt (120 micrograms/kg BW) during either 30 to 60, 30 to 100, 30 to 110, 60 to 100 or 60 to 110 kg BW. Thus, three gilts and three barrows in each of three pens received each treatment. Pigs were slaughtered at either 60 kg BW (1 d after rpSt injection) or 110 kg BW (1 d, 10 d or 70 d after rpSt injection). Relative to controls, pigs injected with rpSt exhibited faster and more efficient growth during the injection period (P less than .05) but slower and less efficient growth during 10 d after cessation of injection (P less than .05). Carcasses of pigs slaughtered 1 d or 10 d after rpSt injection were leaner than controls (P less than .05), but among the pigs treated with rpSt, carcasses of pigs withdrawn from rpSt for 10 d contained more fat (P less than .05) and had a lower percentage of muscle (P less than .05) than carcasses of pigs withdrawn from rpSt for 1 d. Growth and carcass measurements were similar (P greater than .05) between controls and pigs killed 70 d after rpSt injection.(ABSTRACT TRUNCATED AT 250 WORDS)     

用ELISA检测猪链球菌病血清抗体（初报）

以2．5％NaCl浸提猪链球菌荚膜多糖抗原,选用2％明胶作封闭液,4％PEG－PBS为血清稀释液,用ELISA检测猪链球菌病血清抗体,特异性强,比琼扩敏感25-250倍,简便快速,在本病诊断、检疫中有一定实用价值。     

Effects of divergent selection for limb weakness on bone and muscle cross-sectional areas in Duroc swine

The relationship of muscle and bone structure to limb weakness was examined in 60 Duroc pigs from 3 lines divergently selected for thoracic limb weakness. The lines were designated high, control, or low, with the low line having inferior thoracic limb structure. At approximately 100 kg, 10 pigs of each line and gender were scored for thoracic limb structure and movement. Right and left thoracic limbs were collected at slaughter. A computerized morphometric image analysis system was used to determine cross-sectional areas of muscles, bones, and soft tissues at levels through the brachium, antebrachium, metacarpus, and digits. The statistical model that was used to analyze the data included the effects of line, sire, gender, and side (left vs right), with weight as a covariate. Total bone area was similar for all 3 lines of pigs at all cross-sectional levels, but significant differences in muscle and other soft tissue areas were observed, including significantly greater extensor area for the antebrachium (P less than 0.001) in low-line pigs than in control- and high-line pigs, smaller total area (P less than 0.05) of the metacarpus in low-line pigs than in control and high-line pigs, and less total area of the medial digit (P less than 0.01) in low-line pigs than in control- or high-line pigs. Total area of bone and soft tissue for each cross-sectional region was significantly greater (P less than 0.05) in boars than in gilts. Side differences also were observed in total cross-sectional areas of bone and soft tissue of the antebrachium, metacarpus, and digits.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effect of vitamin E and copper on the vitamin E status and performance of growing pigs

A 13-wk trial was conducted with 32 pigs to determine the effects of dietary Cu (250 ppm) and alpha-tocopheryl acetate (ATA, 22 IU/kg) on the performance, serum enzymes, serum and tissue tocopherols, and antibody production in growing pigs. Pigs were fed corn-soybean meal diets containing 21% CP the first 4 wk and 18% CP during the rest of the trial. All feed was stored a minimum of 14 d before it was fed. The addition of Cu decreased (P less than .01) the concentration of alpha-tocopherol in the feed. alpha-Tocopherol concentrations were less than .01 mg/kg in the starter diet and less than 2 mg/kg in the grower diet after 14 d of storage. Supplemental Cu or ATA had no effect on ADG, feed intake, or gain:feed during the first 4 wk. During wk 5 to 13, the addition of Cu to diets containing no ATA increased daily feed intake and decreased gain:feed, but with ATA addition, feed intake decreased and gain:feed increased, resulting in a Cu x ATA interaction (P less than .05). The addition of Cu or ATA had no effect (P greater than .1) on serum glutathione peroxidase or lactic dehydrogenase activity. Serum tocopherols were reduced (P less than .05) by the addition of Cu during wk 1 to 4, 6 (P less than .01), and 7 (P less than .05) and increased (P less than .01) by ATA addition during the entire experiment. The addition of ATA increased the tocopherol concentrations in bile, ham, heart, pancreas, kidney, spleen, liver, psoas and longissimus muscle (P less than .01), kidney fat, backfat, and adrenal gland (P less than .05).(ABSTRACT TRUNCATED AT 250 WORDS)     

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)     

Evaluation of cimaterol for finishing swine including a drug withdrawal period

One hundred fifty crossbred pigs (55 kg) were allotted by weight, sex and litter to a randomized complete-block design with five dietary treatments, six blocks per treatment and five pigs per pen with sex equalized across treatments. Corn-soybean meal-based diets (.65% lysine) with 0, .25 and .5 mg/kg cimaterol were fed, on an ad libitum basis, to pigs slaughtered at an average pen weight of 104 kg/pig. Drug withdrawal prior to slaughter was 1, 3 and 5 d for pigs fed cimaterol at .25 mg/kg and 1 d for those fed cimaterol at .5 mg/kg of diet. Dietary cimaterol level influenced (quadratic, P less than .01) average daily gain during the first 42 d on test; however, daily feed intake and feed conversion ratio were not affected (P greater than .1). Pigs fed .25 mg/kg cimaterol with a 1-d drug withdrawal had 6.8, 7.7 and 13.5% less 10th rib fat depth and 11.1, 6.1 and 13.3% less P2 fat depth than those subjected to either a 3- or 5-d drug withdrawal or those fed the 0 mg/kg cimaterol diet (control), respectively. Overall, pigs fed cimaterol had 7.9% larger longissimus muscle area and 2.6% more kilograms of muscle than pigs fed the control diet. Cimaterol fed at .5 mg/kg resulted in higher (P less than .05) Warner-Bratzler shear force values and altered the proportion of saturation in some long-chain fatty acids, although the total saturated:unsaturated fat ratio was not affected. Pigs fed no cimaterol had less thaw loss (P less than .05) than did those fed other treatments.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effect of protein and(or) carbohydrate fractions of dried whey on performance and nutrient digestibility of early weaned pigs

One hundred eighty 3-wk-old pigs (initial weight 4.8 kg) were utilized in a 35-d growth trial to determine the effects of the carbohydrate and(or) protein fraction of dried whey on pig performance. In addition, 30, 3-wk-old pigs (initial weight 4.9 kg) were used in two digestion trials to study the effects of the whey fraction on nutrient digestibility. Dietary treatments included a corn-soybean meal diet (control), control + 20% dried whey, control + 14.4% lactose, control + 2.1% lactalbumin, control + 14.4% lactose + 2.1% lactalbumin, and control + 8.4% whey protein concentrate. Pelleted diets containing equal lysine concentrations were fed. Lactose and lactalbumin were added at the same levels as provided by a 20% dried whey diet. Pigs fed diets containing milk products exhibited superior (P less than .05) ADG and efficiency of feed utilization and greater (P less than .05) apparent digestibilities for DM, energy and N compared with pigs fed the control diet. Including either lactose or lactalbumin in the diet for the early weaned pig resulted in similar gain, feed efficiency and nutrient digestibility. These results indicate that both the carbohydrate (lactose) and protein (lactalbumin) fractions of dried whey are important in explaining the beneficial response to dried whey elicited in the weanling pig.     

Fluctuating ambient temperature for weaned pigs: effects on performance and immunological and endocrinological functions

Following weaning at 3 wk of age, crossbred barrows and gilts were housed in temperature-controlled rooms for a 5-d adjustment period at 35 degrees C, then assigned to receive constant ambient temperature (CT) or fluctuating ambient temperature (FT) treatment for the nursery phase of the experiment. Pigs in FT received 12 h at 35 degrees C and 12 h at 15 degrees C daily for the initial 2 wk of the experiment, then 12 h at 29 degrees C and 12 h at 9 degrees C daily for the final 2 wk. Pigs in CT received 35 degrees C and 29 degrees C continuously for the first and final 2 wk, respectively. Weekly growth performance, feed intake and feed-conversion efficiency were not affected by treatment. Plasma glucose, serum cortisol, monocyte phagocytic function and antibody response to a commercial E. coli bacterin were similar in pigs exposed to CT and FT treatments. Concentrations of insulin in serum were similar between treatments at 0, 1 and 3 wk but were increased for pigs in FT at 2 (P less than .05) and 4 wk (P less than .01). Numbers of lymphocytes, band neutrophils and monocytes in pigs were not influenced by ambient temperature treatment. However, numbers of mature neutrophils for pigs in FT were increased (P less than .05) at 1 and 3 wk of treatment. Eosinophils were also elevated in FT pigs at 4 wk of treatment. Pairs of littermate pigs that had been given CT and FT treatments were selected randomly to continue on the finishing phase of the experiment.(ABSTRACT TRUNCATED AT 250 WORDS)