Biomedical subjects

D M Webel

Publications and source records attributed to D M Webel.

13 recordsLinked to original sources

PubMed2000

Feeder location did not affect performance of weanling pigs in large groups.

Crossbred pigs weaned at 17 d of age (n = 1,760; mean initial BW = 5.6 +/- 0.7 kg) were used in two 4-wk trials (four replicates per trial) to evaluate the effects of three pen designs on pig performance. The designs were 1) large group size (100 pigs/pen) with five two-sided feeders in a single, central location in the pen; 2) large group size (100 pigs/pen) with five two-sided feeders in multiple (five) locations in the pen; and 3) small group size (20 pigs/pen) with a single two-sided feeder in a central location in the pen. Each feeder provided two 20.3-cm-wide feeding places on each side. Pigs had free access to feed and water. Feeder-trough space (4 cm/pig) and floor-area allowance (0.17 m2/pig) were the same for all treatments. Pigs in the large-group treatments were lighter (15.6 and 15.6 vs 16.0 kg; P < 0.01) at the end of wk 4 and had lower ADG (358 and 357 vs 373 g; P < 0.01) and ADFI (510 and 521 vs 544 g; P < 0.01) during wk 2 through 4 than pigs in small groups. Gain:feed ratio was similar (P > 0.05) for all treatment groups throughout the study. For large groups, feed disappearance from each of the five feeders was similar (P > 0.05) for both multiple- and single-location treatments. In summary, large group size reduced pig growth performance, but the approach to providing multiple feeding locations that was employed in this experiment did not increase feed intake or growth performance of pigs in the large groups.

Animal Feed↗

PubMed2000

The effects of citric acid on phytate-phosphorus utilization in young chicks and pigs.

Several bioassays were conducted with young chicks and pigs fed phosphorus (P)-deficient corn-soybean meal diets. With diets for chicks containing .62% Ca and .42% P (.10% available P), graded doses of a citric acid + sodium citrate (1:1, wt:wt) mixture (0, 1, 2, 4, or 6% of diet) resulted in linear (P < .01) increases in both weight gain and tibia ash. Relative to chicks fed no citric acid, tibia ash (%) and weight gain (g/d) were increased by 43 and 22%, respectively, in chicks fed 6% citric acid. Additional chick trials showed that 6% citric acid alone or sodium citrate alone was as efficacious as the citric acid + sodium citrate mixture and that 1,450 U/kg of phytase produced a positive response in bone ash and weight gain in chicks fed a diet containing 6% citrate. Varying the Ca:available P ratio with and without citrate supplementation indicated that citric acid primarily affected phytate-P utilization, not Ca, in chicks. Moreover, chicks did not respond to citrate supplementation when fed a P-deficient (.13% available P), phytate-free casein-dextrose diet. Young pigs averaging 10 to 11 kg also were used to evaluate citric acid efficacy in two experiments. A P-deficient corn-soybean meal basal diet was used to construct five treatment diets that contained 1) no additive, 2) 3% citric acid, 3) 6% citric acid, 4) 1,450 U/kg phytase, and 5) 6% citric acid + 1,450 U/kg phytase. Phytase supplementation increased (P < .01) weight gain, gain:feed, and metatarsal ash, whereas citric acid addition increased only gain:feed (P < .05) and metatarsal ash (P < .08). A subsequent 22-d pig experiment was conducted to evaluate the effect of lower levels of citric acid (0, 1, 2, or 3%) or 1,450 U/kg phytase addition to a P-deficient corn-soybean meal diet. Phytase supplementation improved (P < .01) all criteria measured. Weight gain and gain:feed data suggested a response to citric acid addition, but this was not supported by fibula ash results (P > .10). The positive responses to phytase were much greater than those to citric acid in both pig experiments. Thus, dietary citric acid effectively improved phytate P utilization in chicks but had a much smaller effect in pigs.

6-Phytase↗

PubMed2000

Group size and floor-space allowance can affect weanling-pig performance.

Crossbred weanling piglets (n = 1,920; mean initial BW, 5.3 +/- .7 kg) were used in two 9-wk trials employing a randomized block design in a 2 x 2 factorial arrangement of treatments to determine effects of group size (20 [Small = S] or 100 [Large = L] pigs/pen) and floor-space allowance (calculated requirement [CR] or calculated requirement less 50% of estimated "free space" [CR-50]) on growth performance. Free space was estimated for each group size. From wk 1 through 4 after weaning, S and L groups at CR were allowed a floor space of .17 m2/pig, and at CR-50, S and L groups were allowed .15 m2/pig and .13 m2/pig, respectively. From wk 5 through 9 after weaning, all CR treatment pigs were provided a floor space of .38 m2/pig, and for the CR-50 treatment, S and L pigs were allowed .32 m2/pig and .28 m2/pig, respectively. Piglets had free access to feed and water. Feeder-trough space per pig was the same for both group sizes. Feed-intake data were collected for only wk 1 through 4. Group size by floor-space allowance interactions (P < .05) were found for gain/feed ratio (G/F) for wk 1 and wk 2 through 4, but not for wk 1 through 4. Piglets in L groups were lighter (P < .001) at the end of wk 1, 4, and 9 by 2, 4, and 5%, respectively, and had lower ADG (6%; P < .001) throughout the trial than S piglets. During wk 1 through 4, feed intake was lower (7%, P < .001) in L piglets than in S piglets, but G/F was similar (P > .05). Piglets in CR groups had greater ADG (5%; P < .01) throughout the trial, with a greater G/F (P < .05) for wk 1 through 4, and were heavier (P < .01) than those in CR-50 groups at the end of wk 4 (3%) and 9 (4%). Pigs in L groups had a greater within-pen coefficient of variation in BW at the end of wk 9 than pigs in S groups. Large groups and reduced floor-space allowance reduced piglet growth performance in the nursery.

Animals↗

PubMed1998

Pretreatment of young pigs with vitamin E attenuates the elevation in plasma interleukin-6 and cortisol caused by a challenge dose of lipopolysaccharide.

The effect of a short-term, high-dose intramuscular injection of d-alpha-tocopherol was studied in pigs given a challenge dose of lipopolysaccharide (LPS). Twenty-four pigs surgically fitted with jugular catheters were used in a 2 x 2 factorial design. Pigs received either 0 or 600 mg d-alpha-tocopherol by intramuscular injection for 3 d before receiving an intraperitoneal injection of saline containing either 0 or 5 microgram/kg body weight Escherichia coli LPS. Blood was collected from indwelling jugular catheters at 0, 1, 2, 4, 6, 8, 12 and 24 h after injection of LPS. Plasma alpha-tocopherol levels were 13-fold greater (P < 0.01) at time 0 in pigs pretreated with 600 mg d-alpha-tocopherol (9.9 +/- 1.3 mg/L) than in those not treated with d-alpha-tocopherol (0.74 +/- 0.09 mg/L). Injection of LPS increased (P < 0.05) plasma levels of interleukin-6 (IL-6) and cortisol at 2-h postinjection, regardless of vitamin E treatment. However, pigs that received alpha-tocopherol before the LPS challenge had substantially lower (P < 0.05) peak levels of IL-6 and cortisol than pigs not receiving alpha-tocopherol. These results suggest that supplementation with a surfeit level of vitamin E reduces the response of pigs to endotoxin.

Animals↗

PubMed1998

Lipopolysaccharide-induced reductions in food intake do not decrease the efficiency of lysine and threonine utilization for protein accretion in chickens.

Exposure of animals to infectious agents induces immune responses that result in reductions in food consumption and weight gain. The effect of these changes on amino acid requirements and utilization remains unclear. Three assays were conducted with young chicks with Escherichia coli lipopolysaccharide (LPS) used to stimulate the immune system. An initial study was conducted to evaluate the effects of LPS on animal performance. In a daily or alternate day injection regimen for 9 d, chicks were given intraperitoneal injections of sterile saline containing 0, 100 or 400 microgram LPS. Administration of 100 or 400 microgram LPS daily, or every other day, decreased both weight gain and food consumption. In two subsequent growth assays, chicks were fed graded levels of lysine or threonine and injected with either 0 or 400 microgram LPS every other day to evaluate the effect of LPS administration on the efficiency of amino acid utilization. At the three lowest amino acid doses, whole-body protein accretion was a linear function of supplemental lysine or threonine intake, and slopes of the accretion curves were not altered by LPS administration. The dietary lysine concentration required to maximize protein accretion was unaffected by LPS, but the absolute lysine intake required to maximize chick performance was lower in LPS-injected chicks than in saline-injected chicks. These results show that LPS administration reduces weight gain, food intake, efficiency of food utilization and the absolute quantity of lysine required to maximize these criteria. However, LPS administration does not affect the efficiency of amino acid utilization, nor does it affect the concentration of dietary lysine required to maximize performance.

Animals↗

PubMed1998

Lipopolysaccharide-induced reductions in body weight gain and feed intake do not reduce the efficiency of arginine utilization for whole-body protein accretion in the chick.

The effects of repeated injections of 400 microg Escherichia coli lipopolysaccharide (LPS) on chick performance from 11 to 22 d posthatching were examined in chicks fed casein-based diets containing graded levels of arginine. Administration of LPS reduced (P < 0.05) weight gain, feed intake, and protein accretion, and there was a tendency (P=0.07) for LPS administration to be more growth-depressing at the higher than at the lower levels of supplemental arginine. Regression analysis of protein accretion for the first three doses of arginine indicated that protein accretion was a linear (P < 0.01) function of supplemental arginine intake for both saline-injected (r2=0.94) and LPS-injected (r2=0.93) chicks. Slopes of the best-fit regression lines for both treatment groups were equal, indicating that arginine utilization for protein accretion was not affected by LPS administration. The dietary arginine concentration required to maximize weight gain and feed efficiency was unaffected by LPS administration, with both saline- and LPS-injected chicks reaching plateaus in weight gain and feed efficiency at 0.90 and 0.98% digestible arginine, respectively.

Animals↗

PubMed1998

D-allothreonine has no growth promoting efficacy for chicks.

One hundred and sixteen crossbred male chicks were used in two battery trials to establish the biological efficacy and toxicity of D-allothreonine (D-allo-Thr) relative to L-Thr. In the efficacy trial, graded doses of D-allo-Thr or L-Thr were added to a Thr-deficient (0.24% L-Thr) chemically defined diet and fed to chicks during the period 10 to 21 d posthatching. Addition of 0, 0.09, and 0.18% L-Thr produced marked linear (P < 0.01) growth and feed efficiency responses, but addition of 0.18 or 0.36% D-allo-Thr did not elicit a response in either weight gain or feed efficiency. In the toxicity trial, 2% D-allo-Thr or 2% L-Thr were added to a conventional 23% CP corn-soybean meal starter diet. During an 11-d feeding period, neither weight gain nor voluntary feed intake were affected (P > 0.10) by 2% additions of either compound. This experiment demonstrates that chicks cannot metabolize D-allo-Thr to L-Thr and that neither L-Thr nor D-allo-Thr are growth depressing when provided in a large surfeit.

Animal Feed↗

PubMed1998

Limiting order of amino acids in a low-protein corn-soybean meal-whey-based diet for nursery pigs.

Three trials were carried out with pigs between 5 and 8 wk of age to determine the limiting order of amino acids in a 13.5% CP corn-soybean meal-based diet containing 8% dried whey. The positive-control diet was a 19.2% CP corn-soybean meal-based diet (1.15% lysine), also with 8% dried whey. Amino acid additions to the low-protein, negative-control diet were based on levels needed to accomplish 110% of ideal ratios (to lysine, set at 1.15%). In Exp. 1, the addition of an amino acid mixture containing Lys, Trp, Thr, Met, Ile, and Val to the low-protein diet increased (P<.05) gain and gain: feed ratio, and these response traits were not different from those of pigs fed the 19.2% CP positive-control diet. Single deletion of Lys from the supplemental amino acid mixture depressed performance to a greater (P<.05) extent than single deletion of any of the other amino acids. Single deletions of Trp, Thr, Met, or Val decreased (P<.05) performance in a similar but lesser magnitude than the decrease caused by Lys deletion, whereas Ile deletion was without effect. Experiments 2 and 3 were designed to evaluate the limiting order of AA beyond Lys in the low-protein diet. Neither His nor Glu were found to be deficient, and, as in Exp. 1, deletion of Trp, Thr, Met, or Val from the supplemental amino acid mixture resulted in performance depressions (P<.05) that were similar. The results suggest that Lys is first-limiting and Trp, Thr, Met, and Val are equally second-limiting in a reduced protein (13.5% CP) corn-soybean meal-based diet with 8% whey for 10-kg pigs.

Amino Acids↗

PubMed1998

Hepatic and renal betaine-homocysteine methyltransferase activity in pigs as affected by dietary intakes of sulfur amino acids, choline, and betaine.

In Exp. 1, young pigs were fed a basal diet containing .17% methionine (Met) (.14% digestible Met), and .48% cystine (.38% digestible cystine) for 14 d (34 to 48 d of age). Treatment additions were .25% DL-Met, .34% betaine, .30% choline, or .25% DL-Met and .34% betaine. Methionine, but not betaine or choline supplementation, increased (P < .05) weight gain and feed efficiency. Hepatic betaine-homocysteine methyltransferase (BHMT) activity was increased (P < .05) by betaine and choline supplementation but was not affected by Met deficiency. Renal BHMT activity was increased (P < .05) by Met deficiency and was further increased (P < .05) by betaine supplementation. In Exp. 2, 10-kg pigs were fed the basal diet from Exp. 1 supplemented with enough DL-Met to bring the total basal Met to .24% (.20% digestible Met). Treatment additions consisted of .20% DL-Met or .34% betaine, and diets were fed for 16 d (34 to 50 d of age). Feed efficiency increased (P < .05) in response to Met, but not to betaine, supplementation. Hepatic BHMT activity increased (P < .05) in response to betaine and Met, but no changes in renal BHMT activity occurred. Although statistically significant changes in hepatic and renal BHMT activity occurred in both experiments, the magnitude of the responses was probably not physiologically important. Therefore, in contrast to previous findings with rats and chicks, it does not seem that hepatic and renal BHMT activity in pigs is influenced substantially by Met deficiency, or by surfeit levels of choline or betaine.

Amino Acids, Sulfur↗

PubMed1997

Time course of increased plasma cytokines, cortisol, and urea nitrogen in pigs following intraperitoneal injection of lipopolysaccharide.

The emerging view is that reduced feed intake, lean muscle accretion, and growth in immunologically challenged pigs is the result of increased cytokine activity, but this has not been directly tested. To begin addressing this issue, 72 crossbred barrows and gilts (11.55 +/- .19 kg BW) were not fed for 12 h and then injected i.p. with 0, .5, or 5 micrograms/kg of Escherichia coli lipopolysaccharide (LPS). Blood was collected by jugular puncture at 0, 2, 4, 8, 12, and 24 h after injection. Plasma levels of tumor necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6), cortisol, plasma urea nitrogen (PUN), NEFA, and triglycerides were determined. Immunological stress was induced by LPS as indicated by increased secretion of TNF-alpha, IL-6, and cortisol. In pigs receiving 5 micrograms/kg of LPS, plasma TNF-alpha was increased 10-fold at 2 h after injection and was still elevated (P < .01) at 4 h. In these same pigs, plasma concentration of IL-6 was increased at 2 h and peaked at 4 h with levels exceeding baseline values by 200-fold (P < .01). Cortisol was elevated at 2, 4, and 8 h after injection (P < .01). The increased secretion of cytokines and cortisol in pigs injected with 5 micrograms/kg of LPS was followed by an increase in protein degradation, as evidenced by PUN values that were increased two- and threefold at 8 and 12 h after injection, respectively. However, unlike previous reports in laboratory animal species, plasma glucose, NEFA, and triglycerides were not altered by LPS. Nonetheless, as the period of feed deprivation progressed from 12 to 36 h, plasma NEFA and triglycerides increased (P < .05) and plasma glucose tended to decrease. We believe that immunological challenge induces cytokine synthesis and secretion in swine which, in turn, may induce protein catabolism.

Animals↗

PubMed1996

Maintenance requirement for valine and efficiency of its use above maintenance for accretion of whole body valine and protein in young chicks.

Experiments were conducted with chicks during the period 10-20 d posthatching to assess valine accretion and protein accretion as a function of incremental valine intakes between 5 and 95% of its ideal level (requirement for maximal growth). Chemically defined crystalline amino acid diets were fed, and amino acids other than valine were maintained at minimized excess levels as valine was increased. With dietary valine concentrations representing 5, 10, 40, 55, 70 and 95% of the ideal level, weight gain (r2 = 0.98), protein accretion (r2 = 0.98) and valine accretion (r2 = 0.99) increased linearly (P < 0.01) as a function of valine intake. Slope of the valine accretion curve was 0.73 +/- 0.02, and there was no indication of decreased valine utilization as valine intake increased to 95% of its required level for maximal growth. Using the linear regression equation, i.e., valine accretion (Y) regressed on valine intake (X), the maintenance valine requirement (X at Y zero) was 18.4 mg/d or 48.8 mg/d per kg body weight3/4. Whole body valine was 4.72 g/100 g whole body protein accreted and was constant at all levels of valine intake. At zero protein accretion, however, valine accretion was negative (-3.8 mg/d). Thus, the valine requirement for zero valine accretion (48.8 mg/d per kg(3/4) was higher than the valine requirement for zero protein accretion (32.4 mg/d per kg3/4). In a subsequent experiment, also involving whole body valine and protein accretion, valine doses of 40, 55 and 70% of ideal were compared using amino acid-balanced diets (amino acids other than valine at 55, 70 and 85% of ideal levels, respectively) or imbalanced diets (amino acids other than valine at a constant 100% of their ideal levels). Straight-line (P < 0.01) valine and protein accretion responses occurred, but slope of the response curves (accretion vs. valine intake) was lower in the imbalanced series than in the balanced series. The results of these studies suggest a constant utilization above maintenance of absorbed valine over a wide range of valine intake.

Analysis of Variance↗

PubMed1996

Sulfur amino acid requirement and cystine replacement value of broiler chicks during the period three to six weeks posthatching.

Three experiments were conducted with commercial broiler chicks to determine the SAA requirement during the growth period 3 to 6 wk posthatching. A 20% CP corn-peanut meal basal diet (3,200 kcal ME(n)/kg) was analyzed to contain 0.23% Met and 0.28% cystine. True digestibility assessment in cecectomized cockerels revealed that Met and cystine in the basal diet were 81 and 75% digestible, respectively. Therefore, the basal diet contained 0.19% digestible Met and 0.21% digestible cystine. When fully fortified with DL-Met, growth rate and feed efficiency of chicks fed the corn-peanut meal diet were equal to that of chicks fed a 20% CP Met-fortified corn-soybean meal diet. In the SAA requirement assay, Ross x Hubbard male chicks were fed graded increments of DL-Met (0.03%) and L-cystine (0.03%) to achieve digestible SAA concentrations of 0.40, 0.46, 0.52, 0.58, 0.64, and 0.70%. Weight gain and feed efficiency responded quadratically (P < 0.01) to increasing doses of SAA. The estimated requirement for maximal feed efficiency was higher than that for maximal weight gain. Both visual appraisal and curve fitting procedures suggested a requirement of close to 0.61% digestible SAA. When extrapolated to a corn-soybean meal diet where SAA true digestibility is 87.5%, the total SAA requirement calculates to be 0.70% of the diet. However, because commercial corn-soybean meal diets typically contain supplemental Met, which is only 81% efficient (wt:wt) in furnishing cystine, the estimated total SAA requirement for chicks fed 20% CP Met-fortified corn-soybean meal diets with 3,200 kcal of ME/kg would probably approximately 0.72% of the diet. A DL-Met vs L-cystine supplementation assay suggested that digestible cystine can supply no more than 52% of the total requirement for digestible SAA of chicks during the 3- to 6-wk growth period.

Amino Acids, Sulfur↗

PubMed1996

Digestible threonine requirement of broiler chickens during the period three to six and six to eight weeks posthatching.

Four experiments were conducted to determine the digestible Thr requirement of commercial broiler chickens (Ross x Hubbard) during the period 3 to 6 and 6 to 8 wk posthatching. Threonine-deficient corn-peanut meal basal diets (3,200 MEn/kg) contained 20% CP and 0.50% Thr for 3- to 6-wk-old birds, and 18.3% CP and 0.50% Thr for 6- to 8-wk-old birds. True digestibility assessment using cecectomized roosters indicated that Thr was 81% digestible in both basal diets. Thus, both diets contained 0.40% digestible Thr. Growth rate and feed efficiency of chicks fed the corn-peanut meal basal diets supplemented with surfeit Thr was equal to that of chicks fed a 20% CP Met-fortified corn-soybean meal diet. Graded doses of Thr produced marked responses (P < 0.05) in weight gain and feed efficiency in birds of both age groups. Maximal feed efficiency was achieved at 0.61% digestible Thr in 3- to 6-wk-old birds and at 0.52% digestible Thr in 6- to 8-wk-old birds. Extrapolating these digestible Thr requirements to total requirements for chicks consuming corn-soybean meal diets (Thr digestibility = 87%) results in estimates of 0.70 and 0.60% for broiler chickens during the growth periods 3 to 6 and 6 to 8 wk posthatching, respectively. These estimates are lower than those of NRC (1994) but are in close agreement with those obtained from ideal protein calculations, i.e., Thr requirements should be 70% of lysine requirements for chicks 3 to 8 wk of age.

Aging↗