Biomedical subjects

L L Southern

Publications and source records attributed to L L Southern.

At least 19 recordsLinked to original sources

PubMed2006

Glycine supplementation to low protein, amino acid-supplemented diets supports optimal performance of broiler chicks.

Six experiments were conducted to determine the effects of low CP in diets for broilers and to evaluate limiting essential and nonessential amino acids (AA) in these diets. All experiments were conducted with Ross x Ross broilers in brooder batteries from 0 to 17 or 18 d posthatch. Treatments were replicated with 6 pens of either 5 or 6 broilers each. In Experiment (Exp.) 1, corn-soybean meal diets were formulated to 16.18, 17.68, 19.18, 20.68, or 22.18% CP. The 22.18% CP diet provided 1.23% Lys and 0.89% TSAA, met or exceeded all nutrient requirements of young broilers, and served as the positive control (PC) diet in all experiments. Increasing dietary CP linearly increased final BW, daily gain (ADG), and gain:feed (G:F) (P < 0.005). In Exp. 2, additions of crystalline essential (EAA) or nonessential AA (NEAA) were added to the low CP diet to simulate the AA profile of the PC. Daily gain, final BW, and G:F were decreased (P < 0.01) when CP was reduced, but the addition of the NEAA increased final BW, ADG, and G:F (P < 0.07) to the level of broilers fed the PC. Addition of EAA alone was without effect. In Exp. 3, chicks fed diets with supplemental Glu, Ala, Asp, or Pro had reduced daily feed intake (ADFI), ADG, and final BW (P < 0.05) compared with the PC diet. Addition of Gly or the combination of Gly, Glu, Asp, Ala, and Pro to the low CP diet increased G:F (P < 0.01) compared with chicks fed PC, and ADG was not different from that of broilers fed the PC diet. In Exp. 4, chicks were fed either the PC diet, the low CP diet with Gly + Ser concentrations of 1.23, 1.35, 1.47, 1.59, 1.71, 1.83, 1.95, or 2.07%, or a 10th diet that contained 1.23% Gly + Ser and with Glu to equal the N concentration of the 2.07% Gly + Ser diet. Final BW, ADG, and G:F were increased linearly (P < 0.001) as the concentration of dietary Gly + Ser was increased. Chicks fed the low CP diet with 2.07% Gly + Ser had growth performance that was not different from that of chicks fed the PC. The addition of Glu to the low CP diet was without effect. In Exp. 5, chicks were fed the PC with additions of 0, 0.15, or 0.30% Gly or the low CP diet containing 1.60, 1.72, 1.84, 1.96, 2.08, 2.20, or 2.32% Gly + Ser. Glycine addition to the PC had no effect, but Gly addition to the low CP diet increased G:F linearly (P < 0.001). Growth performance of chicks fed the low CP diet with 2.32% Gly + Ser was equal to that of chicks fed the PC diet. In Exp. 6, chicks were fed the PC or the low CP diet containing 1.80, 1.95, 2.10, 2.25, 2.40, 2.55, 2.70, 2.85, or 3.00% Gly + Ser. Glycine addition to the low CP diet increased G:F linearly (P < 0.001). In summary, low CP diets result in optimal growth of broilers with Gly + Ser levels of 2.44%.

Amino Acids↗

PubMed2006

The effects of phytase on growth performance and intestinal transit time of broilers fed nutritionally adequate diets and diets deficient in calcium and phosphorus.

Five experiments (Exp.) were conducted to determine the effects of phytase on growth performance and intestinal transit time in chicks fed nutritionally adequate diets and diets deficient in Ca and nonphytate P (nPP). In Exp. 1 and 2, chicks were fed a nutritionally adequate diet from 0 to 6 d or from 0 to 4 d posthatching; assay periods were 8 or 10 d; average initial BW were 98 or 79 g; and average final BW were 371 or 369 g, respectively. Treatments were replicated with 12 pens of 5 chicks each. Corn-soybean meal (C-SBM) diets were adequate in all nutrients except Ca and nPP where appropriate. The treatments were 1) C-SBM, 1.0% Ca, and 0.45% nPP; 2) C-SBM, 0.80% Ca, and 0.25% nPP; 3) Diet 1 + 600 phytase units/kg of diet; 4) Diet 2 + 600 phytase units/kg of diet. Experiments 3, 4, and 5 were conducted to determine the effects of phytase on intestinal transit time in broilers. Broilers were fed the same nutritionally adequate diet from 0 to 18, 27, or 23 d posthatching, and the assay periods were 7 d. Treatments were replicated with 18 individually penned broilers. Average initial BW were 768, 1,108, or 838 g, and average final BW were 1,299, 1,704, or 1,392 g in Exp. 3 to 5, respectively. Transit time data were collected on d 1 and 7 of the Exp. Diets were 1) C-SBM, 0.9% Ca, and 0.35% nPP; 2) C-SBM, 0.80% Ca, and 0.25% nPP + 600 phytase units/kg of diet. Transit time was calculated as the difference between the time feed was first ingested and the time of first appearance of solid feces. In Exp. 1 and 2, the reduction in dietary Ca and nPP reduced (P < 0.01) average daily gain (ADG), average daily feed intake (ADFI), and gain:feed. Phytase addition increased (P < 0.02) ADG and ADFI in diets deficient in Ca and nPP and in the nutritionally adequate diets. In Exp. 2, the reduction in Ca and nPP reduced (P < 0.01) toe and tibia ash percentage, but phytase addition increased (P < 0.01) toe and tibia ash percentage. The increase in toe ash percentage was greater in chicks fed the Ca and nPP deficient diet than in chicks fed the nutritionally adequate diet (Ca and nPP x phytase, P < 0.01). In Exp. 3, 4, and 5, transit time on d 1 was faster (P < 0.03) in chicks fed phytase. On d 7, transit time tended to be faster in chicks fed phytase, but the effect was not significant (P = 0.15). These data indicate that phytase increases ADG and ADFI in diets deficient in Ca and nPP and in diets formulated to be adequate (or excess) in all nutrients for broiler chicks. The increase in ADG and ADFI in chicks fed the nutritionally adequate diet may be due to a faster transit time of feed through the digestive tract, resulting in a greater feed intake and gain.

6-Phytase↗

PubMed2006

Estimation of nutrient requirements using broken-line regression analysis.

We evaluated and compared various broken-line regression models and SAS (SAS Inst. Inc., Cary, NC) procedures for estimating nutrient requirements from nutrient dose response data. We used the SAS (Version 9) procedures NLIN and NLMixed and the response data of Parr et al. (2003), who evaluated the isoleucine requirement of growing swine. The SAS NLIN was used to fit 2 different broken-line regression models: a simple 2 straight-line, one-breakpoint model and a quadratic broken-line model in which the response below the single breakpoint was quadratic; there was a plateau above the breakpoint. The latter was fit using 2 different approaches in NLIN. We also used SAS NLMixed to fit 3 different broken-line models: the 2 straight-line, one-breakpoint model that included a random component for the plateau; the quadratic broken-line model that included a random component for the plateau; and the quadratic broken-line model that included random components for both the plateau and the slope of the curve below the requirement. The best fit (greater adjusted R2; least log likelihood) was achieved using SAS NLMixed and the quadratic model with a random component for asymptote included in the model. Model descriptions, SAS code, and output are presented and discussed. Additionally, we provide other examples of possible models and discuss approaches to handling difficult-to-fit data.

Algorithms↗

PubMed2006

Effects of supplemental L-tryptophan on serotonin, cortisol, intestinal integrity, and behavior in weanling piglets.

Stress occurs in intensive pig farming when piglets are weaned and mixed. In this study, we investigated whether this stress might be reduced with elevated dietary levels of Trp. The effects of supplemental dietary Trp (5 g/kg of feed, as-fed basis) were tested on the neuroendocrine system, intestinal integrity, behavior, and growth performance in nursery pigs, both before and after mixing. Mixing occurred 5 d after weaning and diet introduction. On d 4, 5, and 6, Trp-fed pigs vs. control pigs showed approximately a 2-fold elevation in plasma Trp concentrations (68 +/- 7 vs. 32 +/- 2 micromol/L; P < 0.001), a 38% increase in hypothalamic serotonin turnover as measured by 5-hydroxyindoleacetic acid:5-hydroxytryptamine (P < 0.001), and an 11 to 18% increase (P < 0.05) in the intestinal villus height:crypt depth. Before (d 4) and at (d 5) mixing, saliva but not plasma cortisol concentrations were reduced (P < 0.02) by approximately 2-fold in Trp-fed pigs vs. control pigs. Intestinal paracellular (horseradish peroxidase) and transcellular (fluorescein isothiocyanate) transport of macromolecules were not affected by dietary treatment, but mixing induced a 2-fold reduction (P < 0.05) in transcellular transport. Behavioral responses (lying and standing) at mixing were not affected by dietary treatment, except on d 10 after diet introduction when Trp supplementation induced more lying and less standing (P < 0.02). Average daily gain and ADFI were not different among dietary groups (P > 0.10). In conclusion, supplemental dietary Trp (5 g/kg) to piglets increased hypothalamic serotonergic activity, reduced the salivary cortisol response to mixing, improved intestinal morphology, and reduced physical activity 10 d after diet introduction. Consequently, diets containing high Trp levels improved neuroendocrine components of stress and increased gastrointestinal robustness but did not affect behavioral reactivity in nursery pigs during weaning and mixing.

Animal Feed↗

PubMed2006

Dietary tryptophan effects on plasma and salivary cortisol and meat quality in pigs.

Four experiments were conducted to determine the effects of supplemental Trp on meat quality, plasma and salivary cortisol, and plasma lactate. Experiment 1 was a preliminary study to measure plasma cortisol concentrations in 4 barrows (50 kg of BW) that were snared for 30 s at time 0 min. Pigs were bled at -60, -30, -15, 2, 4, 6, 8, 10, 15, 20, 25, 30, 45, 60, 90, and 120 min. Plasma cortisol was near maximum 10 min after the pigs were snared. In Exp. 2, 20 barrows (50 kg of BW) were allotted to a basal corn-soybean meal diet or the basal diet with 0.5% supplemental l-Trp for 5 d. After the 5-d feeding period, pigs were snared for 30 s and bled at -10, 0, 2, 4, 6, 8, 10, 15, 20, 25, 30, 45, 60, 90, and 120 min after snaring. Pigs fed the diet with supplemental Trp had a lower (P < 0.01) mean plasma cortisol than pigs fed the basal diet. Plasma lactate also was decreased (P < 0.07) by supplemental Trp. In Exp. 3, the same pigs and treatments were used as in Exp. 2, but 5 pigs were snared and 15 pigs adjacent to those being snared were bled to determine if pigs are stressed when they are adjacent to pigs being snared. For pigs adjacent to snared pigs, the area under the curve (P < 0.06) and mean for plasma cortisol was lower (P < 0.01) in pigs fed Trp relative to those fed the basal diet. In Exp. 4, 90 barrows (initial BW of 106 kg) were allotted to 6 treatments in a 3 x 2 factorial arrangement. Three diets with Trp (basal diet, basal supplemented with 0.5% Trp for 5 d, or pigs fed the basal diet with a 0.1 g/kg of BW Trp bolus given 2 h before slaughter) were combined with 2 handling methods (minimal and normal handling). Dressing percent, 24-h pH, and 24-h temperature were reduced in the minimally handled pigs (P < 0.10) compared with the normally handled pigs. Pigs fed Trp in the diet relative to those fed the basal diet had increased 45-min temperature, Commission Internationale de l'Eclairage (CIE) redness (a*) and yellowness (b*) values, and drip and total losses (P < 0.10). Tryptophan in bolus form decreased 45-min pH in the minimally handled pigs but increased 45-min pH in the normally handled pigs (handling x Trp bolus interaction, P = 0.08). Tryptophan in the diet increased CIE lightness (L*) in minimally handled pigs but decreased CIE L* in the normally handled pigs (handling x Trp diet interaction, P = 06). No other response variables were affected by handling method or Trp. Results indicate that Trp decreases plasma cortisol but has no positive effect on meat quality.

Animal Feed↗

PubMed2006

Growth and intestinal morphology of pigs from sows fed two zinc sources during gestation and lactation.

An experiment was conducted to compare the effects of organic (Zn AA complex, ZnAA) and inorganic Zn (ZnSO4) sources on sows and their progeny during gestation and lactation and on the pigs during the nursery period. The dietary treatments were 1) a corn-soybean meal diet with 100 ppm Zn from ZnSO4 (control); 2) diet 1 + 100 ppm additional Zn from ZnSO4; and 3) diet 1 + 100 ppm additional Zn from ZnAA. Dietary additions were on an as-fed basis. Thirty-one primaparous and multiparous sows were allotted to the treatment diet beginning on d 15 of gestation and continuing through lactation. At weaning (d 17 of age), 202 pigs (63, 55, and 84 pigs for treatments 1 to 3, respectively) were allotted to the same dietary treatment as their dam. The pigs were fed a 3-phase diet regimen during the nursery period: d 0 to 7 (phase I); d 7 to 21 (phase II); and d 21 to 28 (phase III). At weaning and at the end of phase III, 1 gilt per replicate was killed, and the left front foot, liver, pancreas, and entire small intestine were removed. Diet had no effect (P > 0.10) on any response during gestation. During lactation, there was an increase (P < 0.10) in litter birth weight in sows fed ZnAA compared with those fed the control or ZnSO4 diets. The sows fed ZnAA nursed more pigs (P < 0.10) than sows fed the ZnSO4 diet, and they weaned more pigs (P < 0.05) than sows fed the control diet. Jejunal villus height of the weaned pigs from sows fed ZnSO4 was increased (P < 0.05) compared with those from the sows fed the control diet. During the nursery period, growth performance was not affected (P > 0.10) by diet. Pigs fed ZnSO4 had greater duodenal villus width (P < 0.05) than those fed ZnAA, and pigs fed ZnSO4 or the control diet had greater ileal villus width (P < 0.05) than those fed ZnAA. Pigs fed ZnSO4 or ZnAA had more (P < 0.05) bone Zn than those fed the control diet. Liver Zn concentration was greatest in pigs fed ZnSO4, followed by those fed ZnAA, and then by those fed the control diet (P < 0.05). Pancreas Zn was increased (P < 0.05) in pigs fed ZnSO4 compared with those fed the control diet. These results suggest that 100 ppm Zn in trace mineral premixes provides adequate Zn for optimal growth performance of nursery pigs, but that 100 ppm additional Zn from ZnAA in sow diets may increase pigs born and weaned per litter.

Animal Feed↗

PubMed2006

Effects of methionine and lysine on fermentation in vitro and in vivo, nutrient flow to the intestine, and milk production.

Three experiments were conducted to investigate the feasibility of using crystalline methionine and lysine as protein supplements for lactating Holstein cows. In the first experiment, Met (dl-methionine) and Lys (l-lysine-HCl) were added to diets used in continuous culture bioreactors to estimate optimal concentrations for use in subsequent in vivo experiments. The second experiment measured ruminal fermentation and nutrient flow to the small intestine when Met and Lys were top-dressed on diets fed to nonlactating cows. The third experiment measured lactation performance when Met and Lys were added to diets fed to late-lactation cows. Providing 0.29 and 2.27% of dry matter as Met and Lys, respectively, provided the largest improvement in fermentation in vitro and these concentrations were used in subsequent experiments. When Met and Lys were top-dressed on diets fed to nonlactating cows, no changes in total tract N digestion were observed. No changes in microbial protein production or ruminal fermentation were observed. Adding Met and Lys did not change production or efficiency of production of milk or milk components by late lactation cows. These data indicate that providing supplemental Met and Lys during late lactation does not significantly improve the protein status of the cow and therefore may not improve milk production.

Ammonia↗

PubMed2005

Effect of protein and energy sources and bulk density of diets on growth performance of chicks.

Four completely randomized designed experiments (EXP) were conducted to determine the effect of energy, amino acid (AA) levels, and bulk density of diets on growth performance of chicks fed diets containing corn (C) or cornstarch:dextrose (CD) as energy sources and soybean meal (SBM) or soy protein isolate (SPI) as protein sources. The chicks were fed C-SBM diets 6 to 8 d posthatching before allotment to treatment, and the assay periods ranged from 7 to 14 d. Initial weights were 86, 93, 94, and 71 g in EXP 1 to 4, respectively. Treatments were replicated 6 to 8 times with 4, 5, or 6 chicks per replicate. In EXP 1, the treatments were 1) C-SBM (1.26% Lys and 3,200 kcal of ME/kg); 2) CD-SPI (1.26% Lys and 3,460 kcal of ME/kg); 3) CD-SPI (1.36% Lys and 3,460 kcal of ME/kg); and 4) CD-SPI (1.26% Lys and 3,200 kcal of ME/kg). The AA in all diets were increased in proportion to Lys. In EXP 2, chicks were fed C or CD as the energy source and SBM or SPI as the protein source in a 2 x 2 factorial arrangement. In EXP 3, the treatments were 1) C-SBM (1.26% Lys and 3,200 kcal of ME/kg); 2) CD-SPI (1.26% Lys and 3,200 kcal of ME/kg); 3) Diet 1 limit-fed to chicks consuming 90% of Diet 2; 4) Diet 2 limit-fed to chicks consuming 90% of Diet 2. In EXP 4, Diets 1 and 2 were the same as Diets 1 and 2 in EXP 3, but fed in mash or pelleted form. In all EXP, chicks with access ad libitum to diets with SPI had decreased (P < 0.02) average daily gain (ADG) and feed intake (ADFI) compared with those with access ad libitum to diets with SBM. In EXP 2, feeding C- or CD-dextrose as the energy source had no effect (P > 0.05) on ADG, ADFI, or gain:feed. In EXP 3, ADG was decreased in chicks fed the diets with SPI relative to those fed diets with SBM, but the decrease was much greater in chicks that had access ad libitum to feed (protein source x feed intake, P < 0.01) than in those limit-fed to the same feed intake. In EXP 4, ADG, ADFI, and gain:feed were decreased (P < 0.01) in chicks fed diets with SPI as the protein source. Pelleting increased (P < 0.01) ADG, ADFI, and gain:feed regardless of protein source, but the increase was much greater in chicks fed the diets with SPI (protein source x feed form, P < 0.01). Results from these EXP indicate that diets with SPI compared with SBM do not result in maximum growth performance in commercial broilers, and the problem may be due somewhat to nutrient deficiency but more to the physical form of the diet.

Animal Feed↗

PubMed2005

The effect of virginiamycin in diets with adequate or reduced dietary calcium or nonphytate phosphorus for broilers.

Four experiments (EXP) were conducted to evaluate the effects of virginiamycin (Vm) in diets adequate or reduced in Ca or nonphytate P (nPP) levels on growth performance and bone response variables in chicks. All diets were corn-soybean meal (C-SBM) based, and all treatments were replicated 6 or 8 times with 5 or 6 chicks each. In EXP 1 and 2, the dietary treatments were 1) C-SBM with 1.00% Ca and 0.45% nPP (positive control; PC); 2) C-SBM with 0.80% Ca and 0.45% nPP (0.80Ca); 3) C-SBM with 1.00% Ca and 0.35% nPP (0.35nPP); and 4 to 6) Diets 1 to 3 with 11 (EXP 1) or 22 (EXP 2) ppm of Vm. In EXP 1, daily gain (ADG), feed intake (ADFI), bone breaking strength (BBS), milligrams of ash per gram of Ca intake (ASH/Ca), and BBS per gram of Ca (BBS/Ca) or nPP (BBS/nPP) intake were increased in chicks fed Vm (P < 0.04 to 0.07). Chicks fed the 0.35nPP diet with Vm had increased ADG, ADFI, BBS, milligrams of tibia ash (ASH), BBS/Ca, and BBS/nPP (nPP x Vm, P < 0.03 to 0.10). Chicks fed the 0.80Ca diet with Vm had increased ASH, milligrams of ASH per gram of nPP intake (ASH/ nPP), and ASH/Ca (P < 0.01 to 0.09). Tibia ash, BBS, gain:feed (G:F), BBS/nPP, and ASH/nPP were decreased in chicks fed the 0.80Ca diet (P < 0.01 to 0.07). Bone ash percentage (BAP), BBS, BBS/Ca, ASH, and ASH/Ca were decreased in chicks fed the 0.35nPP diets (P < 0.01); ASH/ nPP was increased (P < 0.01). In EXP 2, BAP, ASH, ASH/ Ca, and ASH/nPP were increased in chicks fed Vm (P < 0.02 to 0.07). Chicks fed the 0.80Ca diet had a decreased ASH/nPP (P < 0.04) but an increased BBS/Ca and ASH/ Ca (P < 0.01 to 0.02). Chicks fed the 0.35nPP diet had decreased ADG, ADFI, G:F, BBS, BAP, ASH, ASH/Ca, and BBS/Ca (P < 0.01 to 0.04), but BBS/nPP and ASH/ nPP were increased (P < 0.01 to 0.04). In EXP 3, the dietary treatments were 1) PC; 2) C-SBM with 0.70% Ca and 0.45% nPP (0.70Ca); 3) C-SBM with 1.00% Ca and 0.25% nPP (0.25nPP); 4 to 6) Diets 1 to 3 with 9 ppm of Vm. The addition of Vm to the 0.25nPP diet decreased BBS (nPP x Vm, P < 0.06), but Vm increased BBS in the 0.70Ca and PC diets (P < 0.02). Chicks fed the 0.25nPP diet had decreased ADG, ADFI, and BBS (P < 0.01), and chicks fed the 0.70Ca diets had reduced ADFI, BBS, and G:F (P < 0.03 to 0.10). In EXP 4, 4 levels of nPP (0.15, 0.25, 0.35, or 0.45%) and 3 levels of Vm supplementation (0, 11, or 22 ppm) in a 4 x 3 factorial arrangement were used. The addition of Vm increased ADG, BBS, ASH, ASH/Ca, and ASH/nPP only in chicks fed diets with 0.35 or 0.45% nPP (nPP x Vm, P < 0.05). Daily gain, ADFI, G:F, BBS, BAP, BBS/Ca, and ASH were increased as nPP levels were increased (P < 0.01), but BBS/nPP and ASH/nPP were decreased (P < 0.01) as nPP levels were increased. The results obtained from these EXP indicate that Vm, regardless of supplementation level, can partially overcome an nPP deficiency when nPP levels are = 0.35%.

Animal Feed↗

PubMed2005

Effect of inorganic versus organic selenium on hen production and egg selenium concentration.

A 28-d experiment using 288 Hy-Line W-36 laying hens was conducted to compare sodium selenite (SS) with Se-enriched yeast (SY). The Se from SS or SY was supplemented into a corn-soybean meal basal diet at 0, 0.15, 0.30, 0.60, or 3.00 ppm, and the basal diet was formulated to provide 0.82% lysine and 2,950 kcal/kg of ME. Each treatment was replicated 4 times with 2 cages of 4 hens per cage in each replicate. Hen production was assessed daily, and 2 eggs per replicate were collected every 4 d for whole-egg Se analysis. Albumen quality was assessed at 2 egg storage temperatures (7.2 vs. 22.2 degrees C) with the eggs collected on d 24 and 28, respectively. The percentage of dirty and cracked eggs was greater (P < 0.04) in hens fed SY than in those fed SS. Percentage hen-day production was not affected (P > 0.05) by diet. Albumen quality of eggs stored at 22.2 degrees C was improved (P < 0.04) in eggs from hens fed SS, but there was no difference (P > 0.05) in albumen quality of eggs stored at 7.2 degrees C. Egg weight was linearly increased (P < 0.01) by SY. Whole-egg Se levels were linearly increased (P < 0.01) as dietary Se level increased for both sources of Se, but eggs from hens fed SY had higher (P < 0.01) Se concentrations than those fed SS. The results from this experiment indicate that percentage hen-day production is not affected by Se source, and that SY increases egg Se concentrations more than SS.

Animal Feed↗

PubMed2005

A comparison of two sources of phytase in liquid and dry forms in broilers.

Research with corn-soybean meal diets was conducted to compare phytase sources in commercial broilers. A Ca to nonphytate P (nPP) ratio of 2.5:1 was maintained in all diets. Experiments 1 and 2 were conducted from d 4 to 13 (experiment 1) or d 9 to 23 post-hatching (experiment 2) in batteries. The 10 treatments used in both experiment were: Diets 1 to 4 = 0.20, 0.25, 0.30, or 0.35% nPP; Diets 5 to 7 = diet 1 plus 100, 200, or 300 phytase units/kg of diet from Natuphos (NAT); and Diets 8 to 10 = diet 1 plus 100, 200, or 300 phytase units/ kg of diet from Ronozyme (RON). As nPP levels increased, daily gain (ADG), feed intake (ADFI), gain:feed, and toe and tibia ash percentage were linearly increased (P < 0.06) in experiments 1 and 2. Incremental addition of phytase, regardless of source, linearly increased (P < 0.07) ADG and ADFI in experiment 1. Broilers fed NAT had higher (P < 0.07) toe ash percentage in experiment 1 and 2, and higher (P < 0.02) ADG and ADFI in experiment 2 than those fed RON. In experiment 3, 3,360 broilers were used to test 2 dry phytase products from 0 to 41 d posthatching in a 3-phase feeding program. The treatments were: Diet 1) adequate Ca and nPP; Diet 2) nPP reduced by 0.20%; Diets 3 to 5 = diet 2 plus 300, 500, or 750 phytase units/kg of diet from NAT; and Diets 6 to 8 = Diet 2 plus 300, 500, or 750 phytase units/kg of diet from RON. Broilers fed the adequate Ca and nPP diet had improved ADG and ADFI overall, and tibia ash weight and percentage in all growth phases (P < 0.03) compared with those fed the reduced Ca and nPP diets. Overall, ADG and ADFI were linearly increased (P < 0.05) by incremental phytase addition in experiment 3. Both NAT and RON produce similar growth and bone ash traits in commercial broilers.

6-Phytase↗

PubMed2005

Comparison of inorganic and organic selenium sources for broilers.

An experiment was conducted to compare the effects of organic and inorganic sources of Se on growth performance, carcass traits, breast and plasma Se concentrations, and plasma glutathione peroxidase (pGPX3) activity in broilers. Broiler chicks were sexed on d 0 and within sex, randomly allotted to dietary treatment. Average initial and final BW of the broilers were 47 and 2,684 g, and the experiment lasted 49 d. A 3-phase feeding program similar to industry recommendations was used, and the basal diets for each phase were corn-soybean meal based. For each growth phase, the basal diet was supplemented with 0 (control) or 0.30 ppm Se from sodium selenite (SS) or Se-enriched yeast (SY). Each treatment was replicated 7 times (4 pens of males and 3 pens of females) with 50 male or 55 female broilers per replicate. Daily gain, feed intake, gain:feed, eviscerated and chill weights, carcass yield, breast weight, and moisture loss from the breast were not affected (P > 0.05) by Se supplementation. Dietary supplementation with SY increased (P < 0.05) muscle and plasma Se concentrations compared with broilers fed the control diet or the diet with SS. Plasma GPX3 activity was not affected (P > 0.05) by Se source or concentration. The results from this experiment indicate that organic Se increases tissue Se concentration, but it does not affect growth performance, carcass traits, or pGPX3 activity compared with inorganic Se.

Animal Nutritional Physiological Phenomena↗

PubMed2005

The interactive effects of Eimeria acervulina infection and phytase for broiler chicks.

An experiment was conducted to determine the interactive effects of Eimeria acervulina infection and phytase in male broiler chicks. Chicks were standardized from 0 to 4 d posthatching, and the assay period was 5 to 15 d. Treatments were replicated with 6 pens of 5 chicks each. The initial and final BW were 67 and 363 g. A corn-soybean meal diet formulated to provide 1.26% total Lys and 3,200 kcal of ME/kg was used, and it was adequate in all other nutrients except Ca and nonphytate P (NPP) when appropriate. The treatments were in a 2 x 2 x 2 factorial arrangement: adequate Ca and NPP (1.0% Ca and 0.45% NPP) or inadequate Ca and NPP (0.80% Ca and 0.25% NPP), 0 or 600 phytase units/kg of diet, and uninfected or infected with 400,000 E. acervulina oocysts on d 0, 3, and 6 of the experiment. Daily gain, average daily feed intake, and gain:feed (GF) were reduced (P < 0.01) by the coccidial infection and the reduction in Ca and NPP. Phytase addition increased (P < 0.02) average daily gain and average daily feed intake, regardless of the Ca and NPP contents of the diet or the presence of coccidiosis. The GF was increased by phytase but only in uninfected chicks (phytase x coccidiosis, P < 0.02). Toe and tibia ash percentages were decreased (P < 0.01) in chicks fed diets deficient in Ca and NPP, but tibia ash was decreased more by Ca and NPP in healthy chicks than in infected chicks (coccidiosis x Ca and NPP, P < 0.02). Phytase increased (P < 0.02) toe and tibia ash but only in diets deficient in Ca and NPP (phytase x Ca and NPP, P < 0.01). Phytase increased toe ash percentage of healthy chicks fed diets deficient in Ca and NPP, but it had less of an effect in infected chicks fed diets deficient in Ca and NPP (coccidiosis x Ca and NPP x phytase, P < 0.08). Also, phytase was less effective in increasing tibia ash percentage in coccidiosis-infected chicks than in uninfected chicks (phytase x coccidiosis, P < 0.02). These data indicate that phytase is effective in the presence of a coccidial infection, but based on GF and tibia ash percentage, it may not be as effective as in uninfected chicks. Also, phytase increased average daily gain and average daily feed intake in uninfected chicks fed diets formulated to be adequate (or in excess) in all nutrients for male broiler chicks.

6-Phytase↗

PubMed2005

Changes in glutathione peroxidase and tissue selenium concentrations of broilers after consuming a diet adequate in selenium.

Three experiments (EXP) were conducted with commercial broilers to develop a low-Se diet for comparing plasma glutathione peroxidase (pGPX3) concentrations and then to compare pGPX3 and plasma and tissue Se concentrations in broilers fed this low-Se diet after being supplemented with sodium selenite (SS) or Se-enriched yeast (SY). With the exception of Se, all diets were nutritionally adequate. The EXP lasted from 0 to 20 or 22 d posthatching, and treatments were replicated with 6 to 8 pens of 6 to 15 chicks per pen. The results of EXP 1 and 2 indicated that a cornstarch-dextrose diet containing 10% torula yeast and 31% soybean meal (SBM) resulted in similar gain as a corn-SBM (C-SBM) diet, but the cornstarch-dextrose-torula yeast-SBM diet with no added Se reduced pGPX3 activity 6-fold. In EXP 3, the treatments were a C-SBM diet with 0 or 0.30 ppm added Se from SS or SY. These diets were fed from 0 to 10 d posthatching. Beginning on d 10, all broilers were fed the cornstarch-dextrose-torula yeast-SBM, low-Se diet. On d 10, 13, 16, 19, and 22, three broilers per replicate were randomly selected for plasma and tissue collection. Treatment differences were significant at P < 0.05. Daily gain, daily feed intake, and gain:feed were not affected by diet during the 0-to-10-d or 0-to-22-d periods. Plasma GPX3 activity and plasma, liver, and breast Se concentrations were greater in broilers previously fed the diets with added Se, regardless of source, than in those fed the C-SBM diet, except for liver Se concentration on d 19 of broilers previously fed the SS diet. The pGPX3 concentrations were not different in broilers previously fed either Se diet on d 10 and 13 but were greater in broilers previously fed the SY diet on d 16, 19, and 22. Plasma Se concentrations were not different in broilers previously fed diets with SS or SY on d 10 and 22 but were greater in broilers previously fed the SY diet on d 13, 16, and 19. Breast Se concentrations were greater in broilers previously fed the SY diet than in those fed the SS diet on each day. Liver Se concentrations were not different in broilers previously fed SS or SY diets on d 19 and 22 but were greater in those previously fed the SY diet on d 10, 13, and 16. These results indicated that SY supplementation in broiler diets resulted in greater tissue Se concentrations than SS and that pGPX3 and tissue Se concentrations remained greater in birds previously fed a diet with SY than in those fed SS after being fed a low-Se diet.

Animal Feed↗

PubMed2005

Threonine and tryptophan ratios fed to nursery pigs*.

The optimal ratio of tryptophan (Trp):lysine (Lys) relative to the ratio of threonine (Thr):Lys was studied in 288 crossbred (Cambrough 15 x Canabrid) nursery pigs from 7.1 to 15.6 kg BW. Treatments were arranged in a 3 x 3 factorial with three calculated ratios of true digestible Thr:Lys (0.55, 0.60, or 0.65) in combination with three Trp:Lys ratios (0.145, 0.170, or 0.195). Treatments were replicated with eight pens of four pigs each. The experiment lasted 28 day with Phase II (222.6 g CP and 11.9 g true digestible Lys/kg diet, initially 24 day of age and 7.1 kg BW) and Phase III (196.2 g CP and 10.1 kg true digestible Lys/kg diet, initially 38 day of age and 9.8 kg BW) diets each fed for 14 day. Threonine by Trp interactions were observed for average daily gain during each period, and for daily feed intake during Phase III and overall. Generally, Trp addition linearly increased gain and feed intake at a Thr:Lys ratio of 0.60 and 0.65 but not at a Thr:Lys ratio of 0.55. Gain:feed was increased linearly with increasing levels of Trp during both periods. There were no main effects of Thr in either time period or overall. Overall, optimal performance was obtained in pigs fed the true digestible Trp:Lys ratio of 0.195 at Thr:Lys ratios 0.60 or 0.65. These results indicate that Trp:Lys ratios above 0.195 may be needed to maximize performance in diets containing wheat and barley.

Animal Feed↗

PubMed2005

Isoleucine requirement of 80- to 120-kilogram barrows fed corn-soybean meal or corn-blood cell diets.

Six experiments were conducted to validate an Ile-deficient diet and determine the Ile requirement of 80- to 120-kg barrows. Experiment 1 had five replications, and Exp. 2 through 6 had four replications per treatment; all pen replicates had four crossbred barrows each (initial BW were 93, 83, 85, 81, 81, and 88 kg, respectively). All dietary additions were on an as-fed basis. In Exp. 1, pigs were fed a corn-soybean meal diet (C-SBM) or a corn-5% blood cell (BC) diet with or without 0.26% supplemental Ile (C-BC or C-BC+Ile) in a 28-d growth assay. On d 14, pigs receiving the C-BC diet were taken off experiment as a result of a severe decrease in ADFI. Growth performance did not differ for pigs fed C-SBM or C-BC + Ile (P = 0.36) over the 28-d experiment. In Exp. 2, pigs were fed the C-BC diet containing 0.24, 0.26, 0.28, 0.30, or 0.32% true ileal digestible (TD) Ile for 7 d in an attempt to estimate the Ile requirement using plasma urea N (PUN) as the response variable. Because of incremental increases in ADFI as TD Ile increased, PUN could not be used to estimate the Ile requirement. In Exp. 3, pigs were fed the C-BC diet containing 0.28, 0.30, 0.32, 0.34, or 0.36% TD Ile. Daily gain, ADFI, and G:F increased linearly (P < 0.01) as Ile increased in the diet. Even though there were no effects of TD Ile concentration on 10th rib fat depth or LM area, kilograms of lean increased linearly (P < 0.01) as TD Ile level increased. In Exp. 4, pigs were fed a C-SBM diet containing 0.26, 0.31, or 0.36% TD Ile. There were no differences in ADFI or ADG; however, G:F increased linearly (P = 0.02), with the response primarily attributable to the 0.31% Ile diet. In Exp. 5, pigs were fed 0.24, 0.27, 0.30, 0.33, or 0.36% TD Ile in a C-SBM diet. There were no differences in growth performance; however, average backfat, total fat, and percentage of fat increased quadratically (P < 0.10) with the addition of Ile. In Exp. 6, pigs were fed a 0.26% TD Ile C-SBM diet with or without crystalline Leu and Val to simulate the branched-chain AA balance of a C-BC diet. There were no differences in ADFI or ADG, but G:F increased (P = 0.09) when Leu and Val were added. In summary, the Ile deficiency of a C-BC diet can be corrected by the addition of Ile, and because ADFI was affected by Ile addition, the PUN method was not suitable for assessing the Ile requirement. The TD Ile requirement for 80- to 120-kg barrows for maximizing growth performance and kilograms of lean is not < 0.34% in a C-BC diet, but may be as low as 0.24% in a C-SBM diet.

Animal Feed↗

PubMed2005

Effect of microbial phytase addition with or without the trace mineral premix in nursery, growing, and finishing pig diets.

Two experiments were conducted to determine the interactive effects of phytase with and without a trace mineral premix (TMP) in diets for nursery, growing, and finishing pigs on growth performance, bone responses, and tissue mineral concentrations. Pigs (initial and final BW of 5.5 and 111.6 kg [Exp. 1] or 5.4 and 22.6 kg [Exp. 2]) were allotted to treatments on the basis of BW with eight (Exp. 1) or six (Exp. 2) replications of six or seven pigs per replicate pen. Pigs were started on the diets the day of weaning (average of 18 d). In both experiments, the treatments were with or without 500 phytase units/kg of diet and with or without the TMP in a 2 x 2 factorial arrangement. The Ca and available P concentrations were decreased by 0.10% in diets with phytase. The nursery phase consisted of Phase I (7 d), Phase II (14 d), and Phase III (13 d) periods. In Exp. 1, 26 of 52 pigs fed the diet without the TMP and without phytase had severe skin lesions and decreased growth performance; therefore, pigs fed this diet were switched to the positive control diet. In Exp. 2, the treatment without the TMP and without phytase had 12 replications instead of six. At the end of Phase III, half these replications were switched to the positive control diet and half were switched to the diet without the TMP but with phytase. In Exp. 1 during Phases II and III and in the overall data, pigs fed the diet without the TMP had decreased ADG and ADFI, but the addition of phytase prevented these responses (phytase x TMP; P < 0.02). Growth performance was not affected by diet during the growing-finishing period. Coccygeal bone Zn and Na concentrations were decreased (P < 0.09) in pigs fed the diet without the TMP, and adding phytase increased (P < 0.03) Zn and Fe concentrations. In Exp. 2 during Phases I and II, pigs fed the diet without the TMP had decreased ADG, but the addition of phytase prevented this response (phytase x TMP; P < 0.10). Pigs fed the diet without the TMP had decreased (P < 0.10) ADG (Phase II and overall), ADFI (Phases II and III and in the overall data), and G:F (Phase III). Coccygeal bone Zn and Cu concentrations were decreased (P < 0.09) in pigs fed the diet without the TMP, and adding phytase increased (P < 0.03) Zn concentration in the bones. These data indicate that removing the TMP in diets for nursery pigs decreases growth performance and bone mineral content, and that phytase addition to the diet without the TMP prevented the decreased growth performance.

6-Phytase↗

PubMed2005

Effects of supplemental dietary phytase and pharmacological concentrations of zinc on growth performance and tissue zinc concentrations of weanling pigs.

Three experiments were conducted to determine the effects of phytase, excess Zn, or their combination in diets for nursery pigs. In all experiments, treatments were replicated with five to seven pens of six to seven pigs per pen, dietary Ca and available P (aP) levels were decreased by 0.1% when phytase was added to the diets, excess Zn was added as ZnO, a basal level of 127 mg/kg of Zn (Zn sulfate) was present in all diets, and the experimental periods were 19 to 21 d. In Exp. 1, pigs (5.7 kg and 18 d of age) were fed two levels of phytase (0 or 500 phytase units/kg) and three levels of excess Zn (0, 1,000, or 2,000 ppm) in a 2 x 3 factorial arrangement. Added Zn linearly increased ADG and ADFI during Phase 1 (P = 0.01 to 0.06), Phase 2 (P = 0.02 to 0.09), and overall (P = 0.01 to 0.02). Gain:feed was linearly increased by Zn during Phase 1 (P = 0.01) but not at other times. Dietary phytase decreased ADG in pigs fed 1,000 or 2,000 ppm Zn during Phase 2 (Zn linear x phytase interaction; P = 0.10), did not affect (P = 0.27 to 0.62) ADFI during any period, and decreased G:F during Phase 2 (P = 0.01) and for the overall (P = 0.07) period. Plasma Zn was increased by supplemental Zn (Zn quadratic, P = 0.01) but not affected (P = 0.70) by phytase addition. In Exp. 2, pigs (5.2 kg and 18 d of age) were fed two levels of phytase (0 or 500 phytase units/kg) and two levels of Zn (0 or 2,000 ppm) in a 2 x 2 factorial arrangement. Supplemental Zn increased ADG and G:F during Phase 2 (P = 0.02 to 0.09) and overall (P = 0.07 to 0.08), but it had no effect (P = 0.11 to 0.89) on ADG during Phase 1 or ADFI during any period. Phytase supplementation increased ADG (P = 0.06) and G:F (P = 0.01) during Phase 2. Gain:feed was greatest for pigs fed 2,000 ppm Zn and phytase (Zn x phytase interaction; P = 0.01). Bone (d 20) and plasma Zn (d 7 and 20) were increased (P = 0.01) by added Zn but not affected (P = 0.51 to 0.90) by phytase. In Exp. 3, pigs (5.7 kg and 19 d of age) were fed a basal diet or the basal diet with Ca and aP levels decreased by 0.10% and these two diets with or without 500 phytase units/kg. Supplemental phytase had no effect (P = 0.21 to 0.81) on growth performance. Reduction of dietary Ca and aP decreased (P = 0.02 to 0.08) ADG, ADFI, and G:F for the overall data. These results indicate that excess dietary supplemental Zn increases ADG and plasma and bone Zn concentrations. Dietary phytase did not affect plasma or bone Zn concentrations.

6-Phytase↗