Effects of peroxidized corn oil on performance, AMEn, and abdominal fat pad weight in broiler chicks.

There is a trend to use more alternative lipids in poultry diets, either through animal-vegetable blends, distillers corn oil, or yellow grease. This has resulted in the use of lipids in poultry diets with a higher concentration of unsaturated fatty acids, which have a greater potential for peroxidation. The objective of this experiment was to determine the effects of peroxidized corn oil on broiler performance, dietary AMEn, and abdominal fat pad weight. The same refined corn oil sample was divided into 3 subsamples, 2 of which were exposed to different peroxidative processes. The 3 diets contained the unperoxidized corn oil (UO), a slowly peroxidized corn oil (SO; heated for 72 h at 95°C with compressed air flow rate of 12 L/min), or a rapidly peroxidized corn oil (RO; heated for 12 h at 185°C with compressed air flow rate of 12 L/min). Diets were fed from 0 to 14 d of age with each lipid fed at a 5% inclusion rate, continuing on from 15 to 27 d of age with each lipid fed at a 10% inclusion rate. There were 6 Ross 708 broiler chicks per cage with 10 replicates for each of the 3 dietary treatments. Abdominal fat pad and excreta collection was performed on d 27. Body weight gain, feed intake and feed efficiency were measured for the 0 to 14 and 0 to 27 d periods. The increased level of peroxidation reduced AMEn in broiler diets (UO = 3,490 kcal/kg; SO = 3,402 kcal/kg; RO = 3,344 kcal/kg on an as-is basis; SEM = 12.9, P ≤ 0.01). No significant treatment differences were observed among oil supplemented birds for BW gain, feed intake, feed efficiency, or abdominal fat pad weight. In conclusion, corn oil peroxidation status resulted in a decrease in dietary AMEn, but had minimal effects on broiler performance or fat pad weights.

Validation of prediction equations for apparent metabolizable energy of corn distillers dried grains with solubles in broiler chicks.

An experiment consisting of 3 nearly identical trials was conducted to determine the AMEn content of distillers dried grains with solubles (DDGS) to validate 4 previously published prediction equations for AMEn of corn DDGS in broilers. In addition, prior research data were used to generate a best-fit equation for AMEn based on proximate analysis. Fifteen samples of DDGS ranging in ether extract (EE) from 4.98 to 14.29% (DM basis) were collected from various dry-grind ethanol plants and were subsequently fed to broiler chicks to determine AMEn content. A corn-soybean meal control diet was formulated to contain 15% dextrose and test diets were created by mixing the control diet with 15% DDGS at the expense of dextrose. In each trial, male Ross × Ross 708 chicks were housed in grower battery cages and received a common starter diet until the experimental period. Each cage was randomly assigned to 1 of the dietary treatments (trial 1 and trial 2: control + 6 test diets, 13 replicates per diet; trial 3: control + 3 test diets, 12 replicates per diet). Experimental diets were fed over a 6-d acclimation period, followed by a 48-h total excreta collection period. On a DM basis, AMEn of the 15 DDGS samples ranged from 1,975 to 3,634 kcal/kg. Analyses were conducted to determine gross energy, CP, EE, DM, starch, total dietary fiber, neutral detergent fiber, crude fiber (CF), acid detergent fiber, and ash content of the DDGS samples. All results were reported on a DM basis. Application of the 4 equations to the validation data resulted in root mean square error (RMSE) values of 335, 381, 488, and 502 kcal/kg, respectively. Least absolute shrinkage and selection operator technique was applied to proximate analysis data for 30 corn coproducts adapted from prior research and resulted in the following best-fit equation: [AMEn (kcal/kg) = 3,673 - (121.35 × CF) + (51.29 × EE) - (121.08 × ash); P < 0.01; R(2) = 0.70; R(2) adj = 0.67; RMSE = 270 kcal/kg]. The RMSE values obtained through validation were not consistent with the expectation of predictive performance based on internal measures of fit for each equation. These results indicated that validation is necessary to quantify the expected error associated with practical application of each individual prediction equation to external data.

Apparent metabolizable energy and prediction equations for reduced-oil corn distillers dried grains with solubles in broiler chicks from 10 to 18 days of age.

An experiment consisting of 2 identically designed trials was conducted to determine the nutrient composition and AMEn content of distillers dried grains with solubles (DDGS) to develop prediction equations for AMEn in broilers. Fifteen samples of DDGS ranging in ether extract (EE) from 3.15 to 13.23% (DM basis) were collected from various dry-grind ethanol plants and were subsequently fed to broiler chicks to determine AMEn content. A corn-soybean meal control diet was formulated to contain 15% dextrose, and test diets were created by mixing the control diet with 15% DDGS at the expense of dextrose. In each trial, 672 male Ross × Ross 708 chicks were housed in grower battery cages with 7 birds per cage (0.06 m(2)/bird) and received a common starter diet until 10 d of age. Each cage was randomly assigned to 1 of 16 dietary treatments, with 6 replicate pens per treatment. Experimental diets were fed over a 6-d acclimation period from 10 to 16 d of age, followed by a 48-h total excreta collection period. Gross energy (GE) and CP of the experimental diets and excreta were determined to calculate AMEn for each DDGS sample. On a DM basis, AMEn of the 15 DDGS samples ranged from 1,869 to 2,824 kcal/kg. Analyses were conducted to determine the GE, CP, EE, DM, starch, total dietary fiber (TDF), neutral detergent fiber (NDF), acid detergent fiber (ADF), and ash content of the DDGS samples. Stepwise regression resulted in the following best-fit equation for AMEn (DM basis) based on the adjusted coefficient of determination (R(2)adj), SE, and prediction error sum of squares (PRESS): AMEn, kcal/kg = -12,282 + (2.60 × GE) + (89.75 × CP) + (125.80 × starch) - (40.67 × TDF; R(2)adj = 0.86; SE = 98.76; PRESS = 199,819; P ≤ 0.001). These results indicated that the composition of DDGS with variable EE content may be used to predict AMEn in broiler chicks.

Swine diets: Impact of carbohydrate sources on manure characteristics and gas emissions.

Swine growers seeking to lower costs and environmental impact have turned to alternative carbohydrate feed sources. A feeding trial was conducted to determine the effect carbohydrate sources have on manure composition and gas emissions. A total of 48 gilts averaging 138 kg BW were fed diets consisting of (a) low fiber (LF) grain, or (b) high fiber (HF) aro-industrial co-product (AICP). The LF diets included corn and soybean meal (CSBM) and barley soybean meal (BSBM). The HF AICP diets were CSBM based and supplemented with one of the following materials: beet pulp; corn distillers dried grains with solubles; soybean hulls; or wheat bran. Diets were fed for 42 d with an average daily feed intake of 2.71 kg d-1. Feces and urine were collected twice daily and added to manure storage containers in which manure slurries were monitored for gas emissions and chemical properties. Manures of animals fed HF diets had significantly (P < 0.05) more excretion of solids, C, N, and organic N, but less total S compared to pigs fed the LF diets. Animals feed HF diets had significantly (P < 0.05) higher levels of ammonia, sulfide, volatile fatty acids, and phenols in manure compared to pigs fed the LF diets. Manure of animals fed HF diets had 30% (P < 0.05) lower NH3 and 17% lower hydrogen sulfide emissions; however, fiber had no impact on odor emissions. Based on the partitioning of nutrients, animals fed HF fiber diets had increased manure retention for C and N but decreased levels of N gas emissions and manure S. There were little differences in manure and gas emissions for animals fed LF diets, but the source of HF AICP diets had a significant impact on manure composition and gas emissions.

Energy determination of corn co-products fed to broiler chicks from 15 to 24 days of age, and use of composition analysis to predict nitrogen-corrected apparent metabolizable energy.

An experiment (3 trials) was conducted to determine the AME(n) of 15 corn co-products obtained from various wet and dry milling plants, and to develop prediction equations for AME(n) based on chemical composition. Co-products included distillers dried grains with solubles (DDGS, n = 6), high-protein distillers dried grains (n = 2), corn germ (n = 2), corn germ meal, corn bran with solubles, corn gluten meal, corn gluten feed, and dehulled, degermed corn. Treatments (15) consisted of 85% inclusion of the corn-soybean meal basal diet combined with a 15% inclusion of each corn co-product, as well as a control diet containing glucose•H(2)O (15%) at the expense of the co-product. In each trial, Ross × Ross 708 chicks (10 birds per pen) were randomly assigned to 16 dietary treatments (12 replicate pens; 4 replicate pens per trial). After a 7-d diet acclimation period from 15 to 22 d of age, a 48-h total excreta collection was conducted for the determination of AME(n). Co-products were analyzed for gross energy, CP, moisture, crude fat, starch, crude fiber, ash, total dietary fiber, neutral detergent fiber, and acid detergent fiber, and hemicellulose was determined by difference. Stepwise regression resulted in the following equation: AME(n), kcal/kg of DM = 3,517 + (46.02 × % crude fat, DM basis) - (82.47 × % ash, DM basis) - (33.27 × % hemicellulose, DM basis) (R(2) = 0.89; SEM = 191; P ≤ 0.01). Removing hemicellulose from the model resulted in the following equation: AME(n), kcal/kg of DM = (-30.19 × % neutral detergent fiber, DM basis) + (0.81 × gross energy, kcal/kg of DM basis) - (12.26 × % CP, DM basis) (R(2) = 0.87; SEM = 196; P ≤ 0.01). These results indicate that nutrient composition may be used to generate AME(n) prediction equations for corn co-products fed to broiler chicks.

Apparent metabolizable energy of crude glycerin originating from different sources in broiler chickens.

An energy balance experiment was conducted to determine the AME(n) of various crude glycerin samples, and to generate an equation to predict AME(n) of crude glycerin based on its chemical composition. Dietary treatments consisted of a corn-soybean meal basal diet with no added glycerin and a basal diet supplemented with 6% glycerin. Crude glycerin samples were obtained from biodiesel production facilities throughout the United States, which use a variety of lipid products as their initial feedstock. Two identical energy balance trials were conducted. In each trial, 864 male broilers (Ross × Ross 708) were fed a common starter diet until 17 d of age when they were switched to 1 of 12 experimental diets (6 replicates per treatment) from 17 to 22 d of age, with a 48-h collection period on d 21 and 22. Nitrogen-corrected apparent metabolizable energy values of crude glycerin samples were estimated by difference, whereby AME(n) of the basal diet was subtracted from the complete diet containing the test ingredient. The AME(n) of the basal diet and US Pharmacopeia-grade glycerin were determined to be 3,085 and 3,662 kcal/kg, respectively, whereas the AME(n) of the 10 crude glycerin samples ranged from 3,254 to 4,134 kcal/kg. Two crude glycerin samples had high levels of fatty acids compared with the other samples (24 and 35% vs. <0.30%), and even though their AME(n) was higher than that of the other glycerin samples (3,806 vs. 3,611 kcal/kg, P < 0.01, respectively), their AME(n) as a percentage of gross energy (GE) was lower than that of the other samples (65.5% vs. 97.4%, respectively; P < 0.01). Including all of the glycerin samples, the stepwise regression equation to predict AME(n) was determined to be: [AME(n) (kcal/kg) = 1,605 - (19.13 × % methanol) + (39.06 × % fatty acid) + (23.47 × % glycerin)]; (R(2) = 0.25; SE = 379; P ≤ 0.01). These data indicate that glycerin is a good source of energy for broilers, and the AME(n) of glycerin is dependent on fatty acid, methanol, and water contents.

Swine diets impact manure characteristics and gas emissions: Part I protein level.

Crude protein (CP) is a key nutrient in swine diets supplying essential amino acids, N, and S to animals for growth are fed in excess to maximize growth. Swine diets reduced in CP and supplemented with crystalline amino acids have been shown effective at maintaining animal growth while increasing overall CP use efficiency. A feeding trial study was conducted to determine the effects of reduced dietary CP levels on manure slurry chemical properties and gas emissions. A total of 24 gilts averaging 111 kg BW were fed corn and soybean meal diets formulated with 8.7, 14.8, and 17.6% CP using crystalline amino acid supplementation in the 8.7 and 14.8% CP diets, but only intact protein, soybean meal, in the diet containing 17.6% CP. Diets were fed for 45 d with an average daily feed intake (ADFI) of 2.70 kg across all diets. Animals were fed twice daily with both feces and urine collected during each feeding and added to animal-specific manure storage containers. At the end of the study, manure slurries were monitored for gas emissions and chemical properties. Increasing dietary CP levels increased manure pH, total solids, total N, and total S, including increased levels of ammonia (NH3), volatile fatty acids, and phenolic compounds. Pigs fed lower CP diets had lower emissions of NH3, branched chain fatty acids (BCFA), and phenol compounds which translated into lower emissions in total odor. Emissions of NH3 and odor were reduced by 8.9% and 4.2%, respectively, for each unit percent decline in dietary CP. Hydrogen sulfide was the dominate odorant associated with manure odor emissions. Based on nutrient mass balance, animal retention of dietary N and S increased by 7.0% and 2.4%, respectively, for each unit percent drop in crude protein fed animals, while C retention in the animal declined by 2.1%.

Swine diets impact manure characteristics and gas emissions: Part II protein source.

Soybean meal is the dominate protein source for swine diets in the world driven largely by economics, nutritive value, and availability; but conditions can change requiring growers to consider more economical and available protein alternatives. A feeding trial was conducted to determine the impact dietary protein source material on manure slurry chemical properties and manure gas emissions. A total of 32 gilts averaging 130 kg BW were fed either a control diet formulated with soybean meal (SB) or an alternative protein source that included corn gluten meal (CG); canola meal (CM); or poultry meal (PM), with all diets containing 176 g protein kg-1. Diets were fed for 45 d with an average daily feed intake of 2.68 kg/d. Feces and urine were collected twice daily after each feeding and added to animal-specific manure storage containers. At the end of the study, manure slurries were monitored for gas emissions and chemical properties. Dietary protein source had a significant effect (P < 0.05) on manure pH, total solids, total C, protein N, and total S. Pigs fed the diets containing CM had significantly higher levels of sulfide, butanoic acid, and branch chain fatty acids compared to pigs fed SB diets (P < 0.05). Pigs fed CM diets had significantly lower emissions of NH3 compared to pigs fed SB diets (P < 0.05). There were no significant differences in C or S emissions or in odorant emission as affected by source of dietary protein. Hydrogen sulfide was the most dominate odorants for all dietary treatments.

Changes in bacterial communities from swine feces during continuous culture with starch.

Bacteria from swine feces were grown in continuous culture with starch as the sole carbohydrate in order to monitor changes during fermentation and to determine how similar fermenter communities were to each other. DNA extracted from fermenter samples was analyzed by denaturing gradient gel electrophoresis (DGGE). A significant decrease in diversity was observed, the Shannon-Weaver index dropped from 1.92 to 1.13 after 14 days of fermentation. Likewise, similarity of fermenter communities to those in the fecal inoculum also decreased over time. Both diversity and similarity to the inoculum decreased most rapidly in the first few days of fermentation, reflecting a period of adaptation. Sequencing of DGGE bands indicated that the same species were present in replicate fermenters. Most of these bacteria were placed in the Clostridium coccoides/Eubacterium rectale group (likely saccharolytic butyrate producers), a dominant bacterial group in the intestinal tract of pigs. DGGE proved useful to monitor swine fecal communities in vitro and indicated the selection and maintenance of native swine intestinal bacteria during continuous culture.

Swine diets impact manure characteristics and gas emissions: Part II sulfur source.

Sulfur is a key nutrient in swine diets and is associated with hydrogen sulfide (H2S) emissions, odor, and respiratory distress of animals. Due to potential increases in S levels in swine diets by using alternative feedstuffs, a feeding trial study was conducted to determine the effect of dietary S source has on manure slurry chemical properties and gas emissions. A total of 24 gilts averaging 139 kg BW were fed a control diet formulated with corn and soybean meal (CSBM) containing 1.80 g S kg-1 or diets containing 3.50 g S kg-1 feed as supplied by calcium sulfate (CaSO4), distillers dried grains with solubles (DDGS), or feather meal (CFM). Diets were fed for 41 d with an ADFI of 2.70 kg/d. Feces and urine were collected twice daily after each feeding and added to the manure storage containers. At the end of the study, manure slurries were monitored for gas emissions and chemical properties. Dietary S source had a significant effect on excretion of DM, C, N, and S in manure. Pigs fed the diets containing DDGS had significantly higher levels of NH3, VFAs, and phenols in manure compared to pigs fed the CSBM diet. Pigs fed diets with organic S (i.e., DDGS and CFM) had lower emissions of H2S compared to pigs fed the diet with inorganic sulfur (CaSO4). In contrast, there were no significant differences in C or N emissions as affected by dietary treatment. Odor and odorant emissions differed by dietary treatment, with pigs fed the CFM diet having the highest odor emissions as compared to pigs fed the control CSBM diet. Pigs fed diets containing CFM and DDGS had a greater percentage of their chemical odor associated with volatile organic compounds while animals fed the CSBM diet or the diet with CaSO4 had greater percentage associated with H2S emissions.

Swine diets impact manure characteristics and gas emissions: Part I sulfur level.

Sulfur is an essential nutrient for animal growth but is also associated with odor and morbidity of animals from swine operations. A study was conducted to determine the effects of increasing dietary S levels in swine diets on DM, pH, C, N, S, VFA, indole, and phenol concentrations in the manure, and on the emissions of C-, N-, and S-containing gases. A total of 24 gilts averaging 152 kg BW were fed diets containing 0.19, 0.30, 0.43, or 0.64% dietary S, as supplied by CaSO4, for 31 d, with an ADFI of 3.034 kg d-1. Feces and urine were collected after each feeding and added to manure storage containers. At the end of the study, manure slurries were monitored for gas emissions and chemical properties. Increasing dietary S lowered manure pH by 0.3 units and increased DM, N, and S by 10% for each 1.0 g S increase kg-1 feed intake. Increased dietary S increased NH3, sulfide, butanoic, and pentanoic acid concentrations in manure. Carbon and N emissions were not significantly impacted by dietary S, but S emissions in the form of hydrogen sulfide (H2S) increased by 8% for each 1.0 g S increase kg-1 feed intake. Odor increased by 2% for each 1.0 g increase of S consumed kg-1 feed intake. Phenolic compounds and H2S were the major odorants emitted from manure that increased with increasing dietary S.

Effects of cereal grain source and supplemental xylanase concentrations on broiler growth performance and cecal volatile fatty acid concentrations from 1 to 40 d of age2.

An experiment was conducted to evaluate the effects of feeding diets varying in cereal grain source and supplemental xylanase concentrations on growth performance and cecal volatile fatty acid (VFA) concentrations of Ross × Ross 708 male broilers from 1 to 40 d of age. A total of 1,536 day-old chicks were randomly distributed into 64 floor pens (24 chicks/pen; 0.08 m2/bird) and fed 1 of 8 dietary treatments (TRT) with 8 replicates per TRT. Experimental TRT were of either corn- (TRT 1 to 4) or wheat-based (TRT 5 to 8) origins. The 4 dietary TRT for each cereal grain source consisted of a positive control (PC) reference diet and 3 reduced AMEn diets (AMEn reduced 66 kcal/kg below PC) with supplemental xylanase at either 0 (negative control), 12,000, or 24,000 BXU/kg. Birds and feed were weighed at 1, 14, 26, and 40 d of age to determine BW gain, feed intake, and feed conversion ratio. At 26 and 40 d of age, cecal contents were collected and pooled per pen (7 birds/pen; 5 replicate pens/TRT) for VFA concentrations. No TRT differences (P > 0.05) in cumulative growth performance were observed. Likewise, no TRT differences (P > 0.05) in acetic or total VFA concentrations were observed at 26 or 40 d of age. However, cereal grain source (P < 0.05) influenced propionic, isobutyric, butyric, and isovaleric concentrations at 26 and 40 d of age with birds receiving the corn-based diets having higher (P < 0.05) cecal propionic, isobutyric, and isovaleric concentrations, and lower (P < 0.05) butyric acid concentrations than those fed the wheat-based diets. These results indicate that dietary cereal grain source may influence individual cecal VFA concentrations. However, supplemental xylanase did not affect broiler growth performance or cecal VFA concentrations. Therefore, future research evaluating factors limiting xylanase responses on broiler growth performance and cecal VFA production is warranted.

Oil source and peroxidation status interactively affect growth performance and oxidative status in broilers from 4 to 25 d of age.

The objectives of this experiment were to evaluate the effect of oil source and peroxidation status on broiler performance and oxidative stress. Broilers (initial BW 85.1 ± 7.8 g) were allotted to 40 cages with 5 birds per cage in a completely randomized design. The 4 × 2 factorial arrangement of treatments consisted of oil source (palm oil, soybean oil, flaxseed oil, and fish oil) and peroxidation status (fresh or peroxidized). Broilers were fed experimental diets for 20 d to measure growth performance; on day 21 of the experiment, plasma and liver samples were harvested for analysis of oxidative stress including thiobarbituric acid reactive substances (TBARS), protein carbonyls (PC), 8-hydroxy-2'-deoxyguanosine (8- OH-2dG), glutathione peroxidase activity (GPx) and superoxide dismutase and catalase (CAT). An interaction occurred between oil source and peroxidation status where broilers fed peroxidized oils had reduced ADFI, ADG, G:F, and plasma GPx in all oil sources except for fish oil (P ≤ 0.04). Plasma 8-OH-2dG was increased by feeding peroxidized oils (P = 0.01). An interaction occurred in liver TBARS where broilers fed peroxidized palm oil had greater liver TBARS compared to fresh palm oil (P = 0.09). An interaction was noted for liver PC where broilers fed palm, flaxseed, and fish oil had similar liver PC regardless of peroxidation status, while broilers fed peroxidized soybean oil had increased liver PC compared to the fresh soybean oil diet (P = 0.04). Oil source affected plasma TBARS and 8-OH-2dG (P = 0.01), plasma PC (P = 0.09), liver 8-OH-2dG (P = 0.08), and liver CAT (P = 0.02). Correlations between oil composition with growth performance and oxidative stress markers imply that oil UFA:SFA, p-anisidine value, DDE, total polar compounds, and polymerized triglycerides should be measured as an indicator of oil quality, with growth performance being correlated to plasma TBARS, PC, and GPx. In conclusion, the degree of unsaturation and peroxidation status of dietary oils affected growth performance and markers of oxidative stress in poultry.

Effects of age and supplemental xylanase in corn- and wheat-based diets on cecal volatile fatty acid concentrations of broilers1.

An experiment was conducted to evaluate the effects of age and supplemental xylanase in corn- or wheat-based diets on cecal volatile fatty acid (VFA) concentrations of Ross × Ross 708 male broilers during weekly intervals from 14 to 42 d of age. Day-old chicks (1,500) were randomly distributed into 60 floor pens (25 chicks/pen; 0.078 m2/bird) and fed 1 of 4 dietary treatments (TRT) throughout the starter (1 to 14 d of age), grower (15 to 28 d of age), and finisher (29 to 42 d of age) phases with 15 replicates per TRT. Dietary TRT consisted of a 2 × 2 factorial arrangement with 2 diet types (corn- or wheat-based) and 2 xylanase inclusions (0 or 16,000 BXU/kg) as the main factors. At 14, 21, 28, 35, and 42 d of age, cecal contents were collected (4 birds/pen) for VFA analysis. Main effects of cereal grain source (P < 0.05) affected propionic, isobutyric, butyric, isovaleric, valeric, and isocaproic acid concentrations at 14, 21, 28, 35, and 42 d of age. Broilers fed corn-based diets had higher (P < 0.05) propionic, isobutyric, isovaleric, valeric, and isocaproic concentrations than those fed wheat-based diets from 14 to 42 d of age. However, broilers fed wheat-based diets had higher (P < 0.05) butyric acid concentrations at 28, 35, and 42 d of age compared with those fed corn-based diets. Individual and total VFA concentrations increased (P < 0.05) linearly from 14 to 42 d of age. Age and cereal grain interacted (P < 0.05) to affect propionic, isobutyric, butyric, isovaleric, and valeric acid concentrations. These results indicate that broiler cecal VFA concentrations are influenced by cereal grain source and age. In contrast, supplemental xylanase inconsistently influenced broiler cecal VFA concentrations. Therefore, future research evaluating factors affecting supplemental xylanase and cecal VFA production in broilers is warranted. Additionally, research investigating cereal grain source effects on cecal microflora development and fermentative patterns may be beneficial for optimizing cecal VFA production in broilers.

The tetrodotoxin-resistant sodium channel SNS has a specialized function in pain pathways.

Many damage-sensing neurons express tetrodotoxin (TTX)-resistant voltage-gated sodium channels. Here we examined the role of the sensory-neuron-specific (SNS) TTX-resistant sodium channel alpha subunit in nociception and pain by constructing sns-null mutant mice. These mice expressed only TTX-sensitive sodium currents on step depolarizations from normal resting potentials, showing that all slow TTX-resistant currents are encoded by the sns gene. Null mutants were viable, fertile and apparently normal, although lowered thresholds of electrical activation of C-fibers and increased current densities of TTX-sensitive channels demonstrated compensatory upregulation of TTX-sensitive currents in sensory neurons. Behavioral studies demonstrated a pronounced analgesia to noxious mechanical stimuli, small deficits in noxious thermoreception and delayed development of inflammatory hyperalgesia. These data show that SNS is involved in pain pathways and suggest that blockade of SNS expression or function may produce analgesia without side effects.

Apparent metabolizable energy of glycerin for broiler chickens.

Three energy balance experiments were conducted to determine AMEn of glycerin using broiler chickens of diverse ages. In experiment 1, two dietary treatments were fed from 4 to 11 d of age. Dietary treatments consisted of a control diet (no added glycerin) and a diet containing 6% glycerin (94% control diet + 6% glycerin). Four dietary treatments were provided in experiment 2 (from 17 to 24 d of age) and 3 (from 38 to 45 d of age). Diets in experiment 2 and 3 were 1) control diet (no added glycerin); 2) 3% added glycerin (97% control diet + 3% glycerin); 3) 6% added glycerin (94% control diet + 6% glycerin); and 4) 9% added glycerin (91% control diet + 9% glycerin). Diets in experiment 1 and 2 were identical, but the diet used in experiment 3 had reduced nutrient levels based on bird age. In experiments 2 and 3, broilers were fed 91, 94, 97, and 100% of ad libitum intake so that differences in AMEn consumption were only due to glycerin. A single source of glycerin was used in all experiments. Feed intake, BW, energy intake, energy excretion, nitrogen intake, nitrogen excretion, AMEn, and AMEn intake were determined in all experiments. In experiment 1, AMEn determination utilized the difference approach by subtracting AMEn of the control diet from AMEn of the test diet. In experiments 2 and 3, AMEn intake was regressed against feed intake with the slope estimating AMEn of glycerin. Regression equations were Y = 3,331x -72.59 (P < or = 0.0001) and Y = 3,348.62x -140.18 (P < or = 0.0001) for experiments 2 and 3, respectively. The AMEn of glycerin was determined as 3,621, 3,331, and 3,349 kcal/kg in experiments 1, 2, and 3, respectively. The average AMEn of glycerin across the 3 experiments was 3,434 kcal/kg, which is similar to its gross energy content. These results indicate that AMEn of glycerin is utilized efficiently by broiler chickens.

Nitrogen-corrected apparent metabolizable energy value of crude glycerol for laying hens.

An experiment was conducted with laying hens to determine the AME(n) value of crude glycerol, a coproduct of biodiesel production. Crude glycerol (87% glycerol, 9% water, 0.03% methanol, 1.26% Na, and 3,625 kcal/kg of gross energy) was obtained from a commercial biodiesel production facility (Ag Processing Inc., Sergeant Bluff, IA). A total of forty-eight 40-wk-old laying hens (Hy-Line W-36) were placed in metabolic cages (2 hens/ cage) and given free access to the experimental diets. A corn and soybean meal-based basal diet (18% CP, 2,875 kcal/kg of AME(n), 4.51% Ca, 0.51% nonphytate P) was formulated with 15% glucose.H(2)O and 1% Celite. Four dietary treatments were created by substituting 0, 5, 10, or 15% crude glycerol for glucose.H(2)O (3,640 kcal/kg of AME(n)). After 7 d of dietary adaptation, excreta were collected twice daily for 3 d, freeze-dried, and analyzed for contents of DM, Kjeldahl N, acid-insoluble ash, and gross energy. Egg production was recorded daily, and eggs were collected on d 7 and 8 of the experiment for calculation of egg mass (egg production x egg weight). Feed consumption was measured over the 10-d experimental period. Egg-production data were analyzed by ANOVA with 4 treatments and 6 replications in a completely randomized experimental design. The AME(n) value of crude glycerol was estimated as the slope of the linear relationship between the inclusion rate of dietary crude glycerol and the glucose-corrected AME(n) value of the experimental diets. No significant treatment effects (P > 0.1) were apparent for egg-production rate (93.0%), egg weight (56.1 g), egg mass (52.2 g/d), or feed consumption (104 g/d). Linear regression analysis (P < 0.001, r(2) = 0.92, n = 24) revealed that the AME(n) value of the crude glycerol used in this study was 3,805 +/- 238 kcal/kg (mean +/- SEM; as-is basis) for laying hens.

Regulation of hepatic peroxisome proliferator-activated receptor alpha expression but not adiponectin by dietary protein in finishing pigs.

Soy protein regulates adiponectin and peroxisome proliferator-activated receptor alpha (PPARalpha) in some species, but the effect of dietary soy protein on adiponectin and PPARalpha in the pig has not been studied. Therefore, the objective of this study was to determine whether soya bean meal reduction or replacement influences serum adiponectin, adiponectin mRNA, serum metabolites and the expression of PPARalpha and other genes involved in lipid deposition. Thirty-three pigs (11 pigs per treatment) were subjected to one of three dietary treatments: (i) reduced crude protein (CP) diet containing soya bean meal (RCP-Soy), (ii) high CP diet containing soya bean meal (HCP-Soy) or (iii) high CP diet with corn gluten meal replacing soya bean meal (HCP-CGM) for 35 days. Dietary treatment had no effect on overall growth performance, feed intake or measures of body composition. There was no effect of dietary treatment on serum adiponectin or leptin. Dietary treatment did not affect the abundance of the mRNAs for adiponectin, PPARalpha, PPARgamma2, lipoprotein lipase or fatty acid synthase in adipose tissue. The mRNA expression of PPARalpha, PPARgamma2, lipoprotein lipase or fatty acid synthetase in loin muscle was not affected by dietary treatment. In liver tissue, the relative abundance of PPARalpha mRNA was greater (p < 0.05) in pigs fed the HCP-Soy diets when compared to pigs fed RCP-Soy or HCP-CGM diets. Hepatic mRNA expression of acyl-CoA oxidase or fatty acid synthase was not affected by dietary treatment. Western blot analysis indicated that hepatic PPARalpha protein levels were decreased (p < 0.05) in pigs fed the RCP-Soy diets when compared to pigs fed the HCP-Soy diets. These data suggest that increasing the soy protein content of swine diets increases hepatic expression of PPARalpha without associated changes in body composition.

Influence of feeding thermally peroxidized soybean oil on oxidative status in growing pigs.

The objectives of this study were to determine whether feeding thermally processed peroxidized soybean oil (SO) induces markers of oxidative stress and alters antioxidant status in pig tissue, blood, and urine. Fifty-six barrows (25.3 ± 3.3 kg initial BW) were randomly assigned to dietary treatments containing 10% fresh SO (22.5 °C) or thermally processed SO (45 °C for 288 h, 90 °C for 72 h, or 180 °C for 6 h), each with constant air infusion rate of 15 liters/minute. Multiple indices of lipid peroxidation were measured in the SO including peroxide value (2.0, 96, 145, and 4.0 mEq/kg for 22.5, 45, 90, and 180 °C processed SO, respectively) and p-anisidine value (1.2, 8.4, 261, and 174 for 22.5, 45, 90, and 180 °C processed SO, respectively); along with a multitude of aldehydes. Pigs were individually housed and fed ad libitum for 49 d which included a 5 d period in metabolism crates for the collection of urine and serum for measures of oxidative stress. On day 49, pigs were euthanized to determine liver weight and analyze liver-based oxidative stress markers. Oxidative stress markers included serum, urinary, and liver thiobarbituric acid reactive substances (TBARS), and urinary F2-isoprostanes (ISP) as markers of lipid damage; serum and liver protein carbonyls (PC) as a marker of protein damage; and urinary and liver 8-hydroxy-2'-deoxyguanosine (8-OH-2dG) as a marker of DNA damage. Superoxide dismutase (SOD), and catalase activity (CAT) were measured in liver, glutathione peroxidase activity (GPx) was measured in serum and liver, and ferric reducing antioxidant power (FRAP) was measured in serum and urine as determinants of antioxidant status. Pigs fed 90 °C SO had greater urinary ISP (P = 0.02), while pigs fed the 45 °C SO had elevated urinary TBARS (P = 0.02) in comparison to other treatment groups. Pigs fed 45 °C and 90 °C SO had increased serum PC concentrations (P = 0.01) and pigs fed 90 °C SO had greater (P = 0.01) liver concentration of 8-OH-2dG compared to pigs fed the other SO treatments. Furthermore, pigs fed 90 °C SO had reduced serum GPx activity in comparison to pigs fed fresh SO (P = 0.01). In addition, pigs fed 180 °C SO had increased liver CAT activity (P = 0.01). Liver GPx and SOD or serum and urinary FRAP were not affected by dietary treatment. These results indicate that dietary peroxidized soybean oil induced oxidative stress by increasing serum PC while diminishing serum GPx, increasing urinary ISP and TBARS, and increasing 8-OH-2dG and CAT in liver.

Effect of lower-energy, higher-fiber diets on pigs divergently selected for residual feed intake when fed higher-energy, lower-fiber diets.

Residual feed intake (RFI) is the difference between observed and predicted feed intake of an animal, based on growth and maintenance requirements. In Yorkshire pigs, divergent selection for increased (Low RFI) and decreased (High RFI) RFI was carried out over 10 generations (G) while feeding a corn- and soybean-meal-based, higher-energy, lower-fiber (HELF) diet. In G8 to G10, representing 4 replicates, barrows and gilts (n = 649) of the RFI lines were fed the HELF diet and a diet incorporating coproducts that were lower in energy and higher in dietary fiber (LEHF). The diets differed in ME, 3.32 vs. 2.87 Mcal/kg, and in neutral detergent fiber (NDF), 9.4% vs. 25.9%, respectively. The impact of the LEHF diet on 1) performance and growth, 2) diet digestibility, 3) genetic parameter estimates, and 4) responses to selection for RFI, when fed the HELF, was assessed. In general, the LEHF diet reduced the performance of both lines. When fed the HELF diet, the Low RFI pigs had lower (P < 0.05) ADFI (-12%), energy intake (-12%), ADG (-6%), and backfat depth (-12%); similar (P > 0.05) loin muscle area (LMA; +5%); and greater (P < 0.05) feed efficiency (i.e., 8% higher G:F and 7% lower RFI) than the High RFI line. These patterns of line differences were still present under the LEHF diet but differences for ADFI (-11%), energy intake (-10%), G:F (+2%), and RFI (-6%) were reduced compared to the HELF diet. Apparent total tract digestibility (ATTD) of the HELF and LEHF diets was assessed using 116 barrows and gilts from G8. When fed the HELF diet, ATTD of DM, GE, N, and NDF were similar between lines (P ≥ 0.27), but when fed the LEHF diet, the Low RFI pigs had greater digestibility (7%, 7%, 10%, and 32%) than the High RFI line (P ≤ 0.04). To measure responses to selection for RFI and estimate genetic parameters, data from all 10 generations were used (HELF; n = 2,310; LEHF, n = 317). Heritability estimates of performance traits ranged from 0.19 to 0.63, and genetic correlations of traits between diets were high and positive, ranging from 0.87 (RFI) to 0.99 (LMA). By G10, RFI in the Low RFI line was 3.86 and 1.50 genetic SD lower than in the High RFI line when fed the HELF and LEHF diets, respectively. Taken together, the results of this study demonstrate that responses to selection for RFI when fed a HELF diet are not fully realized when pigs are fed an extremely LEHF diet. Thus, feeding diets that differ from those used for selection may not maximize genetic potential for feed efficiency.