Biomedical subjects

D C Mahan

Publications and source records attributed to D C Mahan.

At least 55 records · Page 3Linked to original sources

PubMed1997

Effects of dietary selenium and vitamin E on boar performance and tissue responses, semen quality, and subsequent fertilization rates in mature gilts.

Three experiments involving 192 crossbred boars evaluated the effects of dietary Se (0 or .5 ppm) and vitamin E (0 or 220 IU/kg) on growth, tissue Se, and alpha-tocopherol concentrations, and on semen quality and its subsequent effect on fertilization rate in mature gilts. Diets formulated used torula yeast and dextrose or cornstarch as the basal feedstuffs and were provided from weaning through sexual maturity. The basal diets averaged .063 ppm Se and 3.46 mg alpha-tocopherol/kg diet. Experiment 1 was a 2 x 2 factorial and conducted as a randomized complete block design in six replicates. Boars were allotted at weaning (initial BW 7.7 kg) with growth and feed performance determined to 145 kg BW. Five boars were killed at weaning and three from each treatment group at periodic intervals to 145 kg BW. Serum and tissue Se and alpha-tocopherol concentration and glutathione peroxidase (GSH-Px) activity were subsequently determined. No performance benefit from either nutrient was demonstrated. Tissue (serum, liver, and testis) GSH-Px activity and Se and alpha-tocopherol concentrations were higher (P < .01) at each period when that respective nutrient fortified the diet. Testis GSH-Px activity increased from weaning to 145 kg BW even when Se was not added to the diet. Experiment 2 was conducted after training three boars from each treatment group of Exp. 1 for semen collection. From 9 mo of age and for a 16-wk period, semen was collected three times weekly and the volume, sperm concentration, motility, and percentage of normal and abnormal sperm were determined. Boars fed either the nonfortified Se or vitamin E diets had sperm with lower motilities (P < .01) and a higher percentage of sperm cells with bent and shoehook tails (P < .01). Diets low in added Se seemed to have a greater detrimental effect on the percentage of motile and abnormal sperm than diets inadequate in vitamin E. Sperm cells had a high concentration of Se and alpha-tocopherol, and a high GSH-Px activity. Experiment 3 was conducted using the boars from Exp. 2; 34 mature gilts were inseminated at 12 and 24 h after estrus. Gilts were killed 5 to 7 d postcoitum and the reproductive tracts were recovered. The semen from boars fed the nonfortified Se diet had a lower fertilization rate of oocytes with fewer accessory sperm penetrating the zona pellucida. The results from these experiments indicate that dietary Se and vitamin E can affect boar semen quality, but the greater effect seemed to be from Se.

Animals↗

PubMed1996

Effect of inorganic or organic selenium at two dietary levels on reproductive performance and tissue selenium concentrations in first-parity gilts and their progeny.

A 2 x 2 factorial arrangement of treatments in a randomized complete block design was conducted at two time periods using a total of 43 first-parity gilts. Two sources of Se (selenite or Se-enriched yeast) were added at .1 or .3 ppm to corn-soybean meal diets to evaluate reproductive performance and gilt and progeny tissue Se contents. Treatment diets were initially provided approximately 60 d before breeding. Gilts were bled at periodic intervals and serum glutathione peroxidase (GSH-Px) activity and Se concentrations were determined. Milk was collected at parturition and at weekly intervals to weaning (21 d) for Se analysis. Liver and loin tissues were collected from stillborn (n = 17) and neonatal pigs (n = 19) before colostrum consumption. Three pigs from each litter were bled at weaning, and six pigs per treatment group were killed (two/litter) and tissue (liver, loin, kidney) collected. Three to four sows per treatment were killed at weaning and tissue (loin, liver, pancreas, kidney) collected. Tissues collected from each were analyzed for Se. Dietary Se level or Se source had no effect (P > .15) on gilt reproductive performance. Gilt serum GSH-Px activity was generally similar at the .1 and .3 ppm Se level for either Se source, whereas serum Se was consistently higher when the dietary Se level was .3 ppm. Colostrum Se content was unaffected by Se source and Se level, but milk Se increased as the dietary Se level increased and when the Se-enriched yeast source was fed, resulting in an interaction response (P < .01). Loin tissue had similar Se contents between stillborn and neonatal pigs. Loin Se content was higher when dietary Se level increased (P < .05) and when the Se-enriched yeast source (P < .01) was fed to gestating gilts. Weanling pig lion Se content increased as dietary Se level increased (P < .01) and when the Se-enriched yeast source was fed (P < .01). A higher liver Se content in weaned pigs also resulted when the dietary Se level was .3 ppm (P < .08) and when the Se-yeast (P < .01) was provided. Weanling pig serum GSH-Px activity was similar regardless of the Se level or Se source fed to the dam, but serum Se increased when the .3 ppm Se level and the Se-yeast was fed to the gilt. If GSH-Px activity is used as the criterion to evaluate Se adequacy, then .1 ppm Se from either Se source was adequate, but if higher milk Se or pig tissue content is desired, then a .3 ppm Se level from the Se-enriched yeast source was superior to inorganic Se.

Animals↗

PubMed1996

Evaluating the efficacy of selenium-enriched yeast and sodium selenite on tissue selenium retention and serum glutathione peroxidase activity in grower and finisher swine.

Three experiments conducted with grower-finisher pigs evaluated sodium selenite and a Se-enriched yeast source at various dietary Se levels on Se retention, tissue and serum Se concentrations, and serum glutathione peroxidase (GSH-Px) activity. Experiment 1 was a balance trial conducted in a 2 x 3 factorial arrangement in a randomized complete block (RCB) design in six replicates. Both Se sources were added at .1, .3, or .5 ppm Se. Crossbred barrows (n = 36) averaging 35.9 kg BW were placed in individual metabolism crates and fed their treatment diets, with feces and urine collected for a 7-d test period. Selenium retention increased as dietary Se levels increased, particularly when the Se-enriched yeast was provided, resulting in a Se source x Se level interaction (P < .01). As dietary Se levels increased, urinary Se increased more when pigs were fed sodium selenite, whereas fecal Se increased more when the Se-enriched yeast was fed; both excretion routes resulting in Se level x Se source interaction responses (P < .01). Experiments 2 and 3 were conducted as RCB involving grower (n = 210) and finisher (n = 266) pigs, respectively, and evaluated the two Se sources each at .1, .3, or .5 ppm Se with a non-Se-fortified basal diet serving as a negative control. In Exp. 2, pigs were fed their treatment diets from 22.2 to 60 kg BW in five replicates, whereas in Exp. 3 diets were fed from 65.8 to 105 kg BW in six replicates. Grower pigs fed sodium selenite had serum GSH-Px activity that reached a plateau at .1 ppm Se and .3 ppm when the Se-enriched yeast source was fed, but the interaction response was not significant (P < .15). During the finisher period, serum GSH-Px activity reached a plateau at .1 ppm Se for both Se sources. Serum Se concentrations were lower at .1 ppm Se when the Se-enriched yeast source was fed, resulting in a source x level interaction response for both grower (P < .05) and finisher (P < .01) periods. Loin Se contents were higher in grower and finisher pigs as dietary Se levels increased when the Se-enriched yeast was fed, resulting in a Se source x Se level interaction (P < .01). The results suggest that more Se was retained in muscle tissue when the Se-enriched yeast source was fed, that serum GSH-Px activity reached a plateau at approximately .1 ppm Se, and that sodium selenite may be more biologically available for GSH-Px activity than the Se-enriched yeast source.

Animals↗

PubMed1996

Effect of supplemental sodium chloride, sodium phosphate, or hydrochloric acid in starter pig diets containing dried whey.

Three experiments involving a total of 606 pigs weaned at 23 +/- 2 d of age were used to evaluate the effects of added dietary Na or Cl or both in combination (NaCl) on postweaning performance responses. A basal diet without added NaCl was formulated to 1.20% lysine using a corn-soybean protein mixture with 20% dried whey (C-SBP-DW) and was used in all experiments. The analyzed content of the basal diet for the three experiments averaged .19% Na, .37% Cl, and 1.37% K. In Exp. 1, NaCl was added to treatment diets at 0, .20, .40, and .60% at the expense of corn. The experiment was a randomized complete block (RCB) design conducted in 14 replicates using a total of 336 pigs (six pigs/ pen). The results demonstrated a linear (P < .01) growth response during the 0- to 7-d and a quadratic (P < .08) response during the 8- to 14-d period. Gain: feed ratio improved quadratically (P < .08) for the 0- to 14-d period. In Exp. 2, Na2HPO4 added to the C-SBP-DW basal diet provided supplemental Na levels of 0, .08, .16, and .24% Na to four treatment diets. The experiment was conducted in six replicates in a RCB design using a total of 144 pigs (six pigs/pen). The results demonstrated a linear (P < .05) growth response during the 0- to 7-d period as Na level increased, but not thereafter, and an improved gain: feed ratio (P < .05) for the 0- to 14-d period. In Exp. 3, Cl was added as HCl at 0, .05, or .10% Cl to the basal C-SBP-DW diet. The experiment was a RCB design conducted in six replicates using a total of 126 pigs (five or six pigs/pen between replicates). The results demonstrated a linear growth (P < .01) and feed intake (P < .08) response during the 0- to 7-d and the 0- to 14-d period to increasing levels of Cl. Feed intake also increased for the 0- to 7-d (P < .08), and 8- to 14-d (P < .05) periods. Stool looseness was unaffected by any of the dietary variables in the three experiments. These results suggest that the NRC (1988) recommendations for Na and Cl for young pigs (< or = 10 kg BW) may need to be increased.

Animal Feed↗

PubMed1995

Effect of initial breeding weight on macro- and micromineral composition over a three-parity period using a high-producing sow genotype.

A total of 36 high-producing F1 (Landrace x Yorkshire) gilts and sows were used to determine total body minerals as influenced by initial breeding weight, age, and reproductive state. Four gilts at 9 mo of age were killed at 120, 135, or 150 kg BW for the determination of total body ash and minerals. An additional two gilts from each weight group were maintained in a nonpregnant state until 24 mo of age and then killed, and six sows from each breeding weight group were killed after completing three reproductive cycles (i.e., 24 mo of age). Total body minerals were quantified from the mineral analysis of all body components, including blood. The mineral spectrum of 25 elements was determined by the Inductively Coupled Plasma spectroscopic method. The results suggested that as BW increased at 9 mo of age, P, K, Na, and Cu contents seemed to reach a plateau at 135 kg BW, whereas Ca increased. Non-pregnant gilts at 24 mo of age had higher (P < .01) body mineral contents than at 9 mo and Ca, P, Mg, K, and Na linearly increased (P < .01) as body weight increased in the older gilts. When sows had completed three reproductive cycles, Ca, P, Mg, K, Na, Al, Zn, and Cu contents were lower (P < .01) than those in similarly aged, nongravid gilts.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗

PubMed1994

Effects of dietary vitamin E on sow reproductive performance over a five-parity period.

A study involving 360 farrowings over a five-parity period evaluated the effects of dietary vitamin E on sow reproductive performance and the subsequent effects on serum, colostrum, and milk tocopherol contents. The 2 x 3 split-split-plot experiment was conducted at two locations that differed in the type of facility (indoor gestation pens/farrowing crates [IP/FC] or outside gestation lots/indoor farrowing pens [OL/FP]) and three dietary levels of dl-alpha-tocopheryl acetate (22, 44, or 66 IU/kg of diet), with five parities nested within sow in a repeated measure design. Sow serum alpha-tocopherol, Se, and glutathione peroxidase (GSH-Px) activity were measured at 30 and 90 d postcoitum and at 21 d postpartum (weaning) during each parity. Colostrum and 7-, 14-, and 21-d milk samples were analyzed for alpha- and gamma-tocopherol and Se concentrations. Three pigs per litter were bled at weaning and their serum was analyzed for alpha-tocopherol and Se concentrations and GSH-Px activity. The results indicated that sow weights and daily lactation feed intakes or litter birth and weaning weights were not affected by dietary vitamin E levels provided to the sow. There was an increased number of pigs born (total, P < .01; live, P < .10) when dietary vitamin E was increased. The incidence of mastitis, metritis, and agalactia decreased (P < .05) as dietary vitamin E was increased. The incidence of mastitis, metritis, and agalactia decreased (P < .05) as dietary vitamin E increased was higher (P < .05) with first- and second-litter sows, and was higher (P < .01) at the location that had the OL/FP facility. Colostrum and milk alpha-tocopherol increased (P < .01) as dietary vitamin E increased. Milk alpha-tocopherol declined linearly (P < .01) from 7 to 21 d postpartum in a parallel manner between dietary vitamin E levels. At weaning, pig serum alpha-tocopherol increased (P < .01) as sow dietary vitamin E level increased. These results support a higher dietary level of vitamin E than currently recommended by NRC (1988) for both gestating and lactating sows.

Animals↗

PubMed1994

Efficacy of magnesium-L-ascorbyl-2-phosphate as a vitamin C source for weanling and growing-finishing swine.

Two experiments were conducted, one with weanling pigs (n = 288) and the second with grower-finisher swine (n = 216), to evaluate the efficacy of dietary vitamin C on various performance and serum measurements. Magnesium-L-ascorbyl-2-phosphate (46% L-ascorbic acid) served as the vitamin C source and was incorporated at dietary levels of 0, 50, or 500 ppm in both experiments. Pigs were allotted by sex, weight, and litter to randomized complete block designs. The nursery trial was conducted at four time periods and contained 12 replicates, whereas the grower-finisher experiment was over four time periods and contained nine replicates. Blood samples were collected initially from nine randomly selected pigs in both experiments, and from each pig within each pen at 2 and 5 wk postweaning, and at the 4- and 8-wk period in the grower-finisher trial. A killed Salmonella typhinurium bacterin was injected i.m. into starter pigs at 2 wk postweaning and at wk 4 and 6 in grower-finisher pigs. Hemagglutination titers were evaluated at 5 wk with the nursery pigs and at the 8-wk period with the grower-finisher swine. At the end of the grower-finisher trial, liver and kidney tissue were analyzed for ascorbate. Starter pigs grew faster (P < .05) and had improved gain:feed ratios (P < .05) when vitamin C was provided during the first 2 wk postweaning, but not during the latter 3-wk period. There was no improvement in pig gain or feed efficiency to vitamin C supplementation during any phase of the grower-finisher period.(ABSTRACT TRUNCATED AT 250 WORDS)

Animal Feed↗

PubMed1993

Dietary clofibric acid increases intestinal fatty acid binding protein activity and apparent lipid digestibility in weanling swine.

The effects of supplementation of dietary clofibric acid (.5% wt/wt) on fatty acid binding protein (FABP) activity, apparent lipid digestibility, and serum cholesterol concentrations were evaluated in weanling pigs. Twenty-four barrows were allotted by weight and litter to a randomized complete block design with two treatments (basal vs clofibric acid) in six replicates. Nutrient digestibility measurements were made for a 2-wk period, after which the pigs were killed and tissues were collected. No differences in BW, liver, proximal small intestine, distal small intestine, and proximal and distal intestinal mucosa weights were observed. Apparent lipid digestibility was greater (P < .05) for the overall 2-wk period in clofibric acid-supplemented pigs (81.5 vs 76.6%). This paralleled the increased FABP activity in the distal small intestine (P < .001) of clofibric acid-supplemented pigs. Proximal intestine and liver FABP activities were unaffected by dietary treatment. Serum cholesterol concentrations were markedly lowered by clofibric acid supplementation. During wk 1, pigs fed the basal diet had twofold greater (P < .01) serum cholesterol concentrations, whereas during wk 2, basal-fed pigs had fourfold greater (P < .01) serum cholesterol concentrations (81.5 vs 18.3 mg/dL). These results suggest that elevated intestinal FABP activities may augment fatty acid absorption from the gastrointestinal tract.

Animal Feed↗

PubMed1993

Evaluating two sources of dried whey and the effects of replacing the corn and dried whey component with corn gluten meal and lactose in the diets of weanling swine.

Three experiments were conducted to evaluate the efficacy of replacing corn and dried whey with corn gluten meal (CGM) and lactose, and to evaluate two sources of edible-grade dried whey that elicited different postweaning pig growth performances. In Exp. 1, two corn-soybean meal (C-SBM) diets without or with 20% dried whey (C-SBM-DW) were formulated to contain 1.15% lysine. A third diet replaced the corn and dried whey component with CGM and lactose. The experiment used 108 crossbred pigs weaned at 23 +/- 2 d of age weighing 6.25 kg BW and was conducted in six replicates as a randomized complete block design. Pig weight gains when the C-SBM-DW diet was fed were poor in one trial, whereas a second trial resulted in improved (P < .01) performance responses to the inclusion of dried whey. The CGM-SBM-lactose diet resulted in pig gains that equaled the performance responses of the C-SBM-DW diet of Trial 2. A second experiment was subsequently designed to evaluate the effects of adding lactose or lactalbumin to the CGM-SBM-DW diets using the two dried whey sources that had been identified as good or poor quality in Exp. 1. Diets included dried whey at a 25% level and were formulated to a low lysine level (.95%) to assess the nutritional efficacy of the dried whey sources.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acids↗

PubMed1993

Effect of pasture, confinement, and diet fortification with vitamin E and selenium on reproducing gilts and their progeny.

A total of 48 gilts were used to evaluate the effects of a corn-soybean meal diet with or without vitamin E and Se fed on pasture or in confinement. The effects of these treatments on gilt serum and tissue alpha-tocopherol and Se concentrations and those of their progeny at weaning (28 d) were evaluated. During gestation, the experiment was a 2 x 2 factorial arrangement of treatments in a split-plot design that compared the housing system (pasture or confinement) and the effect of diets fortified with or without vitamin E (22 IU/kg) and Se (.3 ppm). The lactation study was a 2 x 2 factorial arrangement of treatments in a split-plot design evaluating the two housing systems during gestation or lactation only when gilts were fed the unfortified basal diet. The gilts fed the vitamin E- and Se-supplemented diet remained either on pasture or in confinement during both reproductive phases and served as positive controls. Gilts were bled at breeding, at 30, 60, and 90 d postcoitum, at farrowing, and at weaning (28 d). Three pigs per litter were bled from all litters at weaning. Six pigs per treatment group were killed at weaning and livers were collected. Pasture lots contained orchardgrass, ryegrass, and alfalfa; different lots were used during each reproductive phase.(ABSTRACT TRUNCATED AT 250 WORDS)

Animal Feed↗

PubMed1993

Evaluation of feed grains with dried skim milk and added carbohydrate sources on weanling pig performance.

Two experiments were conducted to evaluate the effects of 1) two grain mixtures and 2) various carbohydrate sources and levels fed to weanling pigs during the initial 2 wk postweaning. A total of 720 crossbred pigs were weaned at 23 +/- 2 d of age at an average BW of 5.8 kg. In Exp. 1, a 2 x 3 factorial experiment in a randomized complete block design was conducted in 12 replicates. Treatment diets formulated to 1.40% lysine were fed for a 14-d period. These diets contained dried skim milk (DSM) at a 45% level and an oat groat-soybean meal (OG-SBM-DSM) or a corn-soybean meal (C-SBM-DSM) mixture. In addition, the diets contained one of three carbohydrate sources (cornstarch, dextrose, lactose) at a 12% level. From 15 to 35 d postweaning, all groups were fed a 1.15% lysine corn-soybean meal (C-SBM) diet. The results demonstrated that during the period from 0 to 14 d weight gains were similar when either grain source was provided, but gain:feed ratio was superior and serum urea N was lower when the OG-SBM-DSM diet was fed. The addition of lactose or dextrose to either grain mixture resulted in greater weight gains (P <.05) than when cornstarch was the carbohydrate source. The second experiment was a randomized complete block design conducted in six replicates. The C-SBM-DSM diet of Exp. 1 served as the positive control diet. The other diets used corn gluten meal (CGM), SBM, and DSM with the three carbohydrate sources added at 22.5 or 35.5%.(ABSTRACT TRUNCATED AT 250 WORDS)

Animal Feed↗

PubMed1993

Effect of initial breeding weight and management system using a high-producing sow genotype on resulting reproductive performance over three parities.

A study was conducted with sows of a high-producing genotype to evaluate their reproductive performance using three breeding weights over a three-parity period in two management systems. A total of 114 F1 gilts (Landrace x Yorkshire) were used in a split-plot, randomized, complete block experiment conducted as a 3 x 2 factorial arrangement of treatments in two replicates. Three gilt breeding weights of 120, 135, and 150 kg were achieved by feeding 1.8, 2.3, or 3.2 kg/d of a .73% lysine corn-soybean meal (C-SBM) diet, respectively, from 5 to 8 mo of age. Two locations, each with different management systems, were considered the main plot and consisted of 1) outside, concrete-floored gestation lots and indoor farrowing pens or 2) indoor gestation pens and farrowing crates. All sows were fed 1.8 (Parity 1) or 2.1 (Parity 2 and 3) kg/d of a .73% lysine C-SBM diet during the breeding and gestation periods, whereas a .82% lysine C-SBM diet with 5% added fat was available ad libitum during lactation. All sows lost weight during the first lactation; larger weight losses occurred as breeding weight increased (P < .01). During the second and third lactations the 135- and 150-kg sow breeding groups had less lactation weight change, whereas the 120-kg group lost more weight, resulting in a breeding weight x parity interaction (P < .01). The 120-kg breeding weight group consumed less feed (P < .05) for the three lactation periods than did the heavier weight groups. Initial breeding weight had no effect on number of pigs born (total, live) or pig and litter weights at birth. Pig mortality increased with increasing breeding weight (P < .01) and parity (P < .05), a response that was exacerbated when sows farrowed in pens vs crates. Postweaning breeding intervals and sow removal from the experiment were not significantly affected by initial breeding weight, but a numerically higher percentage of sows in the 120-kg group were anestrous or failed to conceive than the percentage of such sows in the heavier weight groups. These data suggest that an initial breeding weight of approximately 135 kg at 8 mo of age may be best when sows farrow in crates, whereas when sows farrow in pens a lower breeding weight may be more desirable.

Adipose Tissue↗

PubMed1993

The dietary protein and(or) lysine requirements of barrows and gilts. NCR-42 Committee on Swine Nutrition.

A cooperative research study involving three experiments and 2,318 pigs was conducted at 12 research stations to evaluate the protein (lysine) requirements of barrows and gilts. The two sexes were penned separately and fed fortified corn-soybean meal diets containing protein levels ranging from 12.0 to 17.2%. Lysine levels in these diets ranged from .52 to .90%. Protein levels in Exp. 1 were 12, 14, and 16%; in Exp. 2, protein levels were 13, 14, 15, and 16%; and in Exp. 3, they were 13.2 15.2, and 17.2%. Fat (5%) was added to one-half of the diets in Exp. 3. Each station that participated contributed a minimum of two replicate pens of pigs per diet-sex combination in a given experiment. Average initial and final weights were 35 and 99 kg in Exp. 1 and 51 and 105 kg in Exp. 2 and 3, respectively. At the end of the test period, pigs were slaughtered and hot carcass weight, 10th rib fat depth, and longissimus muscle area were measured. Percentage of carcass muscle was estimated from these data. Overall, barrows gained weight faster than gilts (P < .01), but gilts required less feed per unit of gain (P < .05) and had less backfat, larger longissimus muscle areas, and a greater percentage of carcass muscle (P < .01) than did barrows. Lean growth rate was similar for barrows and gilts (332 vs 329 g/d). Increasing the dietary protein or lysine level resulted in improved rate and efficiency of gain and increased carcass leanness and lean growth rate in gilts, but the increase was less pronounced or did not occur in barrows, resulting in protein level x sex interactions. Feeding low-protein (12 or 13%) diets decreased performance and carcass leanness to a greater extent in gilts than in barrows. The pooled data from the three experiments indicated that most traits tended to reach a plateau at 13% CP (.60% lysine) in barrows, whereas in gilts, weight gains, feed/gain, carcass muscle, and lean growth rate continued to improve, but at a decreasing rate, with up to 17.2% CP (.90% lysine). The results indicate that gilts require higher concentrations of dietary amino acids to maximize lean growth rate than do barrows.

Adipose Tissue↗

PubMed1993

Effect of dietary lysine levels formulated by altering the ratio of corn:soybean meal with or without dried whey and L-lysine.HCl in diets for weanling pigs. NCR-42 Committee on Swine Nutrition.

A regional cooperative study (NCR-42 Committee) evaluated the efficacy of supplemental dried whey and L-lysine.HCl in a corn-soybean meal-based diet for weanling pigs. The experiment involved five research institutions using a total of 960 crossbred pigs weaned between 3 and 4 wk of age. The experiment was conducted as a randomized, complete block design in 15 replications with a minimum of two replicates per station. Two diets were formulated to contain either .95 or 1.10% lysine by altering the ratio of corn:soybean meal (C-SBM). Two other diets were formulated to the same lysine levels but with 20% dried whey (C-SBM-DW). Supplemental L-lysine.HCl was added to each diet mixture as another variable, increasing the lysine level of each diet by .15%. There were station effects (P < .01) for each trait, but no station x treatment interactions (P > .15). Feed intakes and weight gains were greater (P < .01) for pigs fed diets containing dried whey, and there was a greater response (26 vs 10%) to the C-SBM-DW diet that contained 1.10% lysine than to the C-SBM-DW diet at the .95% lysine level. Performance was not improved when L-lysine.HCl was added to either the .95 or 1.10% lysine C-SBM diets, and it elicited a small, but nonsignificant, gain response when it was added to the C-SBM-DW diets. These results suggest that gain and feed performance responses of weanling pigs improved when diets contained dried whey. Lysine was not the limiting factor in either the C-SBM or C-SBM-DW diet formulated to either .95 or 1.10%. Another factor in dried whey was assumed to be responsible for its growth promotion effect.

Animal Feed↗

PubMed1993

Effect of weight, split-weaning, and nursery feeding programs on performance responses of pigs to 105 kilograms body weight and subsequent effects on sow rebreeding interval.

An experiment using a total of 288 crossbred pigs from sows of two parties (1 or 3) were used in a 2 x 2 factorial arrangement of treatments in a randomized complete block design conducted in 12 replicates to evaluate pig weight and split-weaning on performance response to 105 kg BW. Pigs were allotted to two weight groups (4.1 to 5.5 kg or 6.8 to 8.2 kg) at 23 d of age and weaned at two ages (23 or 30 d). The lightweight pigs weaned at 23 d were fed a high-nutrient-dense diet (HNDD) for a 2-wk period, whereas those weaned at 30 d were fed the HNDD for 1 wk. Both groups were fed a corn-soybean meal-dried whey (C-SBM-DW) and a C-SBM diet, each for a 2-wk period. The heavyweight group weaned at 23 d was fed the HNDD for 1 wk, followed by the C-SBM-DW and C-SBM diet, each for 2 wk, whereas those weaned at 30 d were fed the C-SBM-DW diet and the C-SBM diet, each for 2 wk. From 20 to 105 kg, pigs of all groups were fed C-SBM diets that met or exceeded nutrient requirements. Sows that lactated for the additional week had litters of four pigs and were allowed to consume a 15% CP lactation diet ad-libitum, whereas sows weaned at 23 d were fed 1.8 kg/d of a 14% CP diet.(ABSTRACT TRUNCATED AT 250 WORDS)

Animal Feed↗

PubMed1992

Intestinal development and fatty acid binding protein activity of newborn pigs fed colostrum or milk.

Newborn pigs (n = 20) were gavage-fed sow's colostrum, defatted colostrum, milk, defatted milk or a 5% lactose solution over 24 h in order to evaluate effects on growth and functional differentiation of small intestine. Colostrum-fed pigs had greater (p less than 0.01) mucosal mass in the proximal half of the small intestine than did the milk- or lactose-fed groups. Total fatty acid binding protein (FABP) activity and FABP activity per mg DNA in proximal intestines of colostrum-fed pigs exceeded that for the lactose group. FABP activities (per g mucosa or mg soluble protein) were greater (p less than 0.01) in the proximal segments of small intestines of pigs fed whole versus the corresponding defatted secretion. These results indicate that the feeding of colostrum specifically augments perinatal intestinal growth and differentiation as manifested by increased cellular hypertrophy and FABP activity. Milk lipid and unidentified factor(s) enriched in colostrum are inducers of intestinal FABP activity.

Animals↗

PubMed1992

Effect of feed intake during late development on pubertal onset and resulting body composition in crossbred gilts.

A total of 105 nonboar-exposed, F2 ([Landrace x Yorkshire] x Duroc) gilts were used in two replicates of a randomized complete block experiment to evaluate the effect of dietary feed intake on pubertal onset and subsequent body composition. Feed intakes were established at 50% of ad libitum (AL-50), 75% of ad libitum (AL-75), or at ad libitum (AL-100) levels from 4.5 to 9 mo of age. A corn-soybean meal diet fed to all gilts was formulated to meet or exceed nutrient requirements except for energy. Puberty was measured by two methods: 1) monitored once daily by back pressure applied by the herdsman or 2) from elevated plasma progesterone concentrations. Body composition was evaluated by the deuterium oxide method after plasma progesterone concentrations were elevated. Daily feed intake for the experimental period averaged 1.6, 2.3, and 3.2 kg, and the BW of gilts at 8 mo of age were 111, 131, and 154 kg for the AL-50, AL-75, and AL-100 groups, respectively. Body weight, backfat thickness, and body fat content increased linearly (P < .01) as feed intake increased, but age at puberty was not severely influenced. A minimum body fat content or percentage did not seem to initiate pubertal onset. There was a trend for a lower percentage of the AL-50 gilts to ovulate (P = .08) than those fed the AL-75 and AL-100 intakes. An inverse relationship resulted between the percentage of gilts that ovulated to the percentage that showed behavioral estrus.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1992

Efficacy of dried whey and its lactalbumin and lactose components at two dietary lysine levels on postweaning pig performance and nitrogen balance.

Two experiments were conducted to determine the efficacy of lactalbumin and lactose components of dried whey on gain and feed performance responses and N retention of weanling swine. In Exp. 1, a 2 x 5 factorial arrangement of treatments in a randomized complete block design in seven replicates was used to evaluate the efficacy of two dietary lysine levels (.90 and 1.30%) in 1) a corn-soybean meal (C-SBM) mixture, 2) C-SBM and 20% dried whey (C-SBM-DW), or the dried whey component replaced with 3 lactalbumin and cornstarch, 4) lactose and an amino acid mixture, or 5) the combination of lactalbumin and lactose. A total of 420 pigs weaned at 23 +/- 2 d of age, weighing an average of 6.87 kg BW, were used in a 3-wk experiment. Experiment 2 was a balance trial conducted as a 3 x 2 x 3 factorial arrangement in a split-plot design in three replicates. The negative (i.e., C-SBM) and positive (i.e., C-SBM-DS) control diets and the C-SBM-lactalbumin-cornstarch diets at the two lysine levels of Exp. 1 were the main plots, each evaluated for a 3-wk postweaning period. Growth rate (P less than .05), feed intake (P less than .01), N retention (P less than .01), and apparent N digestibility (P less than .05) were increased when pigs were fed the C-SBM-DW compared with the C-SBM diet.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acids↗