Pasture intake of grazing livestock needs to be estimated to allow determination of energy and nutrient intakes. It is commonly estimated by difference, subtracting intakes of other feeds from estimated needs for dry matter or energy. However, these estimates are often erroneous, because they do not take individual animal variation for growth, reproductive status or activity level into account. One method that has had success in grazing ruminants has been the use of markers, or tracers, to estimate fecal output and nutrient digestibility. External markers are dosed to the animal and can be used to determine fecal output. Internal markers are an inherent part of the diet in question and can be used to determine dry matter and nutrient digestibilities. These estimates can then be used to give estimates of intake. These studies were conducted to evaluate the effectiveness of traditional marker methods in determining fecal output, digestibility, and thus intake in grazing horses. The first trial was conducted on 8 mature mares and geldings, housed in stalls, to determine if a common external marker, Cr, could be used to determine fecal output. Horses were dosed once daily with a molasses, Cr, and hay mixture for 12 d. Feces were collected throughout the day into individual tubs so that total fecal output (TC) could be measured. Daily fecal Cr excretion values (Ct, mg/kg DM) were fit to a monoexponential equation with one rate constant (k), rising to an asymptote (Ca): Ct = Ca - Ca.e-kt. Superior fits were found when a delay (d) was incorporated into the equation, estimating the time required for Cr to enter the prefecal pool: Ct = Ca - Ca.e-k(t-d). Estimates of fecal output (FO) were calculated using the equation: FO = Cr dose-d / Ca and provided good estimates when compared to TC values. Subsequent trials evaluated to use of internal markers and more frequent dosing of Cr to improve estimates of intake. Eight mature geldings were housed in stalls and were fed 2 hays in a replicated Latin Square design. The monoexponential equation with the delay continued to fit the data well. Thrice daily dosing of Cr improved the predictions of FO, when dosing was every 8 h. The internal marker, yttrium (Y) consistently overestimated digestibility (D). The internal markers, n-alkanes, gave a better estimate of digestibility. When the digestibility estimates were combined with the FO estimates to estimate dry matter intake (DMI, kg/d): DMI = [FO / (1-D)]*100, the combination including n-alkanes gave better estimates. Further studies found that dosing Cr for 12 d did not improve the fit of the monoexponential equation compared to dosing for only 8 d. Marker methods that had been developed in stalls were applied to grazing horses, and results continued to be promising. / Ph. D.

Fecal recoveries of n-alkanes were determined in three digestion balance experiments consisting of two periods each. Each experiment compared two diets in a switch-back design using eight mature Thoroughbred geldings. Horses were randomly assigned to two groups of four and offered one of two mixed grass/legume hays (Diets 1 and 2) in Exp. 1, mixed grass/legume hay and one of two concentrates (Diets 3 and 4) in Exp. 2, and mixed grass/legume pasture (Diets 5 and 6) in Exp. 3. In Exp. 1 and 2, horses were housed in stalls and in Exp. 3, two horses from each diet were housed in stalls and two horses remained on pasture. Balance periods lasted 11 days with d 1 to d 7 consisting of a dietary accommodation period, followed by 4 days of total collection. Results indicated that fecal recoveries of odd-chain alkanes (C25 to C33) were less than 100 % and similar between chain lengths. Estimates of DMD (DE) were similar to the total collection DMD (DTC) for Diet 1 in Exp. 1, but underestimated DTC for Diet 2 in Exp. 1 (P < .05) and Diets 3 and 4 in Exp. 2 (P < .05). For Diet 5 in Exp. 3, the DE for stall-fed horses using C25 and C33 was similar to DTC, whereas C27, C29, and C31 underestimated DTC (P < .05). For pastured horses, the DE using C29 and C31 were similar to DTC, whereas C25, C27, and C33 underestimated DTC (P < .05). For Diet 6 in Exp. 3, the DE for stalled horses calculated using C25 was similar to the DTC, whereas use of C27, C29, C31, and C33 underestimated DTC (P < .05). For pastured horses, the DE using C29 was similar to DTC, whereas all other alkanes underestimated DTC (P < .05). When DE was adjusted (DA1) using the mean recovery of each odd-chain alkane, DA1 was similar to DTC for Diet 2 in Exp. 1, Diets 3 and 4 in Exp. 2, and stalled horses offered Diets 5 and 6 in Exp. 3. The DA1 using C25 underestimated DTC for Diet 1 in Exp. 1 (P < .05). For pastured horses offered Diet 5, DA1 for C33 was not different from the DTC estimate, whereas all other DA1 for n-alkanes overestimated DTC (P < .05). For pastured horses offered Diet 6, DA1 for C29 and C31 overestimated, but were similar to the DTC, whereas the DA1 for C33 underestimated DTC and was similar to the DTC. The DA1 for C25 and C27 overestimated DTC (P < .05). When DE was adjusted for the mean recovery of all n-alkanes (DA2), all DA2 estimates for stalled horses in Exp. 1, 2, and 3 were similar. In pastured horses offered Diets 5 and 6 in Exp. 3, the DA2 overestimated DTC (P < .05). These results suggest that accurate mean estimates of DMD can be obtained by adjusting for mean recovery of each odd-chain alkane in a specific diet. / Master of Science

No description available.

The current research program was designed to evaluate the impact of various dietary and ingredient nutrient profiles and exogenous enzyme inclusion on growth performance and energy utilization in broilers. Experiment one was designed to observe increasing levels of distillers’ dried grains with Solubles (DDGS) and a non-starch polysaccharide degrading enzyme (NSPase) on energy digestibility. Experiment two evaluated the influence nutrient variation in corn and xylanase supplementation on growth performance and nutrient utilization. In experiment one, DDGS concentration was increased from 0 to 15% in 5% increments and included the addition of an NSPase enzyme. Early broiler body weight and FCR was negatively affected with increasing DDGS concentration up to 15%. The decreased growth performance was associated with a decrease in energy and nitrogen utilization as a linear decrease was observed in IDE, INDC, and AMEn. Addition of the NSPase negated many of the negative effects on nutrient utilization as improvements in all digestibility measurements were observed. Interactions were observed with DDGS concentration and NSPase inclusion as the benefit of enzyme inclusion was augmented as DDGS level increase. Experiment two evaluated different corn crops from six geographical locations in the US in an effort to determine the effects of xylanase inclusion and corn nutrient variation on growth performance and nutrient utilization. Significant differences were observed in growth performance, IDE, and AMEn in broilers when fed corn. Corn source impacted early body weights, and FCR throughout the experiment. Energy utilization was also impacted on all measured parameters, following the starter phase (day 17) and at the conclusion of the trial (day 41) by corn source. Xylanase inclusion improved FCR during the finisher phase as well as the cumulative FCR (day 1-41). Digestibility data indicates that corn source impacts the xylanase effectiveness in young broilers, as improvements were not observed in all corn types. Xylanase inclusion, however, did increase IDE and AMEn in all corn sources on day 41 of age. Data from this research program confirm that ingredient nutrient content, through the presence of ingredients with anti-nutritive properties or the incidence of varying nutrient profiles, does impact observed growth performance as related to reduced nutrient digestibility. Additionally, the inclusion of a dietary exogenous enzyme does improve energy and nitrogen digestibility in broilers, ultimately improving growth performance of broilers and improving efficiency.

Master of Science / Department of Grain Science and Industry / Greg Aldrich / Novel ingredients fuel growth in the pet food market. Sorghum grain is a promising ingredient source. It grows in semi-arid regions and the pericarp is rich in phenolic compounds that are well-known antioxidants. The objectives were to determine the impact of milling sorghum on yield and composition of the various fractions, their impact on diet extrusion, and nutrient utilization when fed to dogs. Sorghum milling yields were 68.3% flour, 27.2% mill-feed, and 1.25% germ. Four nutritionally similar dog diets were extruded containing whole sorghum (WSD), sorghum flour (FLD), sorghum mill-feed (MFD), or a control diet (CON) with an equal proportion of corn, wheat and rice. The MFD had the highest (P < 0.05) bulk density and was 1.37-fold heavier than FLD. The FLD had a sectional expansion index (SEI) of 1.92 and 1.35-fold more than MFD and WSD. The FLD and MFD had the hardest kibbles (P < 0.05). Twelve Beagle dogs were fed the experimental diets in a 4 period replicated Latin square design with 9 d adaptation and 5 d total fecal collection (TFC). Fecal output was also estimated using acid insoluble ash (AIA), Cr₂O₃ and TiO₂. Plasma antioxidant activity was measured by oxygen radical absorbance capacity (ORAC) method. Fecal scores were highest (P < 0.05) for MFD treatment and lowest for CON, with FLD and WSD similar to both extremes. Dogs fed the MFD had the largest quantity (P < 0.05) of feces excreted and FLD the least. Dogs fed the FLD had highest (P < 0.05) overall nutrient digestibility values; whereas, MFD had the lowest values. TiO₂ estimates of fecal output correlated best to all other markers. The MFD had more than 2-fold (P < 0.05) the antioxidant value by ORAC versus the other treatments (20,482 vs average 8,923 μM Trolox Equivalent/L). This study suggests that sorghum flour would benefit easy-to-digest foods and the sorghum mill-feed could benefit foods needing indigestible fiber and antioxidants. Titanium dioxide may be a better marker for fecal output than Cr₂O₃ or TFC. Future work should determine the optimal mill-feed level to provide health benefits without affecting nutrient digestibility.

Renewable energy sources, such as lignocellulosic biomass, are environmentally friendly because they emit less pollution without contributing net carbon dioxide to the atmosphere. Among lignocellulosic biomass, corn stover is a very useful feedstock to economically produce environmentally friendly biofuels. Corn stover was pretreated with an excess of calcium hydroxide (0.5 g Ca(OH)2/g raw biomass) in non-oxidative and oxidative conditions at 25, 35, 45, and 55oC. The optimal condition is 55oC for 4 weeks with aeration, determined by yields of glucan and xylan. The overall yields of glucose (g glucan hydrolyzed/100 g original glucan) and xylose (g xylan hydrolyzed/100 g original xylan) were 91.3 and 51.8 at 15 FPU/g cellulose, respectively. Furthermore, when considering the dissolved fragments of glucan and xylan in the pretreatment liquors, the overall yields of glucose and xylose were 93.2 and 79.5 at 15 FPU/g cellulose, respectively. The pretreatment liquor has no inhibitory effect on ethanol fermentation using Saccharomyces cerevisiae D5A. At the recommended condition, only 0.073 g Ca(OH)2 was consumed per g of raw corn stover. Under extensive delignification conditions, 87.5% of the initial lignin was removed. Extensive delignfication required oxidative treatment and additional lime consumption. Deacetylation quickly reached a plateau within 1 week. Delignification highly depended on temperature and the presence of oxygen. Lignin and hemicellulose were selectively removed, but cellulose was not affected by lime pretreatment in mild temperatures (25 ?? 55oC). The delignification kinetic models of corn stover were empirically determined by three simultaneous first-order reactions. The activation energies for the oxidative delignification were estimated as 50.15 and 54.21 kJ/mol in the bulk and residual phases, respectively. Crystallinity slightly increased with delignification because amorphous components (lignin, hemicellulose) were removed. However, the increased crystallinity did not negatively affect the 3-d sugar yield of enzyme hydrolysis. Oxidative lime pretreatment lowered the acetyl and lignin contents to obtain high digestibility, regardless of crystallinity. The enzymatic digestibility of lime-treated biomass was affected by the change of structural features (acetylation, lignification, and crystallization) resulting from the treatment. The non-linear models for 3-d hydrolysis yields of glucan and xylan were empirically established as a function of the residual lignin fraction for the corn stover pretreated with lime and air.

Three experiments were conducted to determine the efficacy of an <i>Escherichia coli</i> 6-phytase (Quantum phytase) in laying hens fed corn-soybean meal based diets. In experiment 1, the Escherichia coli 6-phytase (Quantum) was evaluated for its efficacy in a 40-wk laying hen production trial. A total of 1080 White Leghorn hens were fed mash corn-soybean meal (CSM) based diets containing 0.35%, 0.25% or 0.15% of non-phytate phosphorus (NPP) with the 0.25% and 0.15% diets containing 200, 400 and 600 U/kg of exogenous phytase. Only minor differences in production characteristics were found between the 0.35% and 0.25% treatments regardless of phytase addition, indicating that 0.25% NPP resulted in P intake that was at or above the hens requirement. In contrast, the hens fed the 0.15% NPP diet without phytase supplementation had significantly reduced production performance in comparison to the 0.35% treatment. The addition of phytase to the 0.15% diet improved these production characteristics to levels equal to or better than the 0.35% diet. The results indicated that Quantum phytase was efficacious in CSM-based diets fed to White Leghorn laying hens and can be used to reduce the need for diet supplementation with inorganic phosphorus. In experiment 2, the effect of Quantum phytase on nutrient digestibility and bone ash in laying hens fed CSM-based diets was investigated. A total of 108 White Leghorn hens were fed CSM-based diets containing 0.35%, 0.25% or 0.15% NPP with the 0.25% and 0.15% diets containing 200, 400 or 600 U/kg of exogenous phytase. A linear reduction in phytate digestibility, ileal protein digestibility and soluble P was reported with increasing levels of exogenous phytase in the 0.25% diet. Tibial bone ash percentage was higher in 61-wk-old hens fed 0.25% diets supplemented with 200 or 400 U/kg phytase. Overall, the Quantum phytase was not efficacious in improving nutrient digestibility in laying hens fed CSM-based diets deficient in NPP. In experiment 3, the impact of dietary Ca and P level on the efficacy of an E. coli-derived 6-phytase and the apparent digestibility of various nutrients was investigated in White Leghorn laying hens fed CSM-based diets. A total of 384 White Leghorn hens were fed CSM-based diets containing four levels of Ca (2.5, 3.5, 4.5 or 5.5%), two levels of NPP (0.15 or 0.30%), and two levels of phytase (300 or 600 U/kg feed). Increasing dietary Ca caused a decrease in AMEn, duodenal protein digestibility, Ca and phytate digestibility, percentage soluble P in feces and the percentage of poor quality eggs, while significantly increasing bone ash and hen-housed and hen-day egg production. The higher level of NPP (0.30%) decreased AMEn, fecal protein, Ca and P digestibility, and hen-housed and hen-day egg production, while increasing fecal soluble P and egg specific gravity in comparison to the lower NPP level. The higher level of dietary phytase (600 U/kg feed) significantly increased AMEn, phytate and P digestibility, soluble P in feces, and hen-day and hen-housed egg production, while significantly reducing the percentage of soft shelled, cracked and broken eggs. Overall, dietary phytase, Ca and NPP levels, either as main effects or in an interactive manner, can affect apparent nutrient digestibility and production traits in laying hens fed CSM-based diets.

In this study, the nutritional value of wheat distillers grains and the effect of further processing of these products on their nutritional value for rainbow trout were investigated in five experiments. In experiments 1 and 2, wheat distillers grains with solubles (WDDGS) was fractionated using grinding, sieving and elutriation sequentially. Apparent digestibility coefficients (ADC) of dry matter (DM), gross energy (GE), acid ether extract (AEE), ash and amino acids (AA) did not differ between the original WDDGS and the WDDGS protein concentrate (P > 0.05). However, the ADC of crude protein (CP) was significantly higher for WDDGS protein concentrate (88.0 %) than the original WDDGS (84.9 %) (P < 0.05). In experiments 3 and 4, the effect of aqueous fractionation on nutritional composition of wheat wet distillers grains (WWDG) from two local ethanol plants (plant 1 and plant 2) was evaluated. Aqueous fractionation increased levels of CP and GE in the processed WWDG from both plants. Fractionation significantly increased the ADC of DM, GE and AEE (P < 0.05). In contrast, protein digestibility was not influenced by the plant or the processing method (P > 0.10). In experiment 5, a 56 d growth trial was performed to determine the effect feeding the aqueous fractionated WWDG to rainbow trout on growth performance. Rainbow trout (n=22/ tank; body weight 136 g and 3 tanks/ treatment) were fed diets containing 0, 75, 150, 225 and 300 g kg-1 of the processed WWDG from plant 2. There were no significant linear or quadratic relationships between inclusion rate and specific growth rate (SGR), average daily gain (ADG) or feed to gain ratios (feed:gain). However, there was a significant negative linear relationship between inclusion rate and average daily feed intake (ADFI) (P < 0.05). The results of these studies suggest that both dry and aqueous fractionation are suitable methods to produce protein concentrates from wheat distillers grains but that the aqueous fractionation process was more effective in improving nutrient composition and increasing digestibility.

The effects of feed processing, pea cultivar and their interaction on the nutritional value of field pea (Pisum sativum L.) for poultry were evaluated in regard to its apparent metabolizable energy (AMEn), apparent protein digestibility (APD), and rate and extent of starch digestion. Amino acid sparing as affected by the rate of starch digestion was studied in laying hens and broiler chickens. Also, the effects of feeding a slowly digested starch (SDS) from pea on performance and metabolism of broiler–breeder pullets were investigated. The first objective of this research was to evaluate the effects of screen–hole size, cold pelleting, and pre–pelleting conditioning temperature on nutrient digestibility of pea. There was no interaction between dietary treatments on all studied parameters. Small hammer–mill screen–hole size (3.2–mm) increased AMEn, APD, and extent of starch digestion values compared with coarse screen–hole size (6.4–mm). The AMEn and extent of protein digestion were not affected by cold pelleting, but the site of protein digestion was affected. In contrast, cold pelleting increased the rate and extent of starch digestion. Pre–pelleting conditioning temperature affected AMEn of pea in a quadratic fashion but had no positive effect on starch digestibility. The 70°C of pre–pelleting conditioning temperature maximized pea AMEn. Increasing pre–pelleting conditioning temperature decreased APD in a linear fashion. The second objective of this research was to study the effects of feed processing, pea cultivar and their interaction on AMEn, APD, and rate and extent of starch digestion. In vitro and in vivo experiments were conducted. An in vitro procedure simulating the gastric and small intestine conditions of chickens was developed to predict the rate and extent of starch digestion as affected by pea cultivar and sieve–hole size (0.5–, 1.0–, 2.0–mm). The rate and extent of starch digestion of cereal grain samples (barley, corn, and wheat) was also compared to pea starch. No interactions were found between pea cultivar and sieve–hole size on the kinetics of starch digestion. Pea cultivar affected the rate and extent of starch digestion. The small sieve–hole size in the in vitro assay resulted in a higher rate and extent of starch digestion. Pea starch was slowly digested in comparison with cereal grains. The in vivo experiment confirmed that fine grinding and pelleting improves AMEn and APD. Cultivar effects on AMEn and APD were observed, but no interaction was found between pea cultivar and feed processing. The third objective of this research was to investigate whether feeding SDS from pea would have sparing effect on amino acid utilization in chickens. In the first experiment, the effects of three levels of pea inclusion 0, 150, 300 g/kg on the response of laying hens to three levels of lysine intake (700, 780, and 860 mg per day) were evaluated using performance and production criteria. This experiment revealed that pea inclusion up to 300 g/kg in laying hen diets was well tolerated by laying hens and improved energy retention as indicated by increased body weight and egg weight. However, this experiment did not confirm the hypothesis that SDS from pea spared amino acids for laying hens. The second experiment investigated the interaction between SDS derived from pea and amino acid levels on the performance and carcass quality of broiler chickens. Six levels of pea inclusion (0, 150, 300, 450, 600, and 750 g/kg) and two levels of amino acids (100 and 85% of Ross × Ross 308 requirement) were examined in a broiler trial (0 – 35 d). The maximum level of pea inclusion recommended in diets increased with broiler age, but the effect of SDS from pea on amino acid sparing could not be confirmed. In the third experiment, the effects of feeding SDS from pea on growth performance and metabolism of broiler breeder pullets were investigated. Body weight and uniformity of pullets fed pea–based diet were similar to that of a wheat–based diet. Target body weight and uniformity of pullets were not affected by feeding a diet containing 890 g/kg of pea. Mean blood glucose levels and relative liver weight were markedly lower in broiler pullets fed pea–based diet compared with those fed a wheat–based diet. In conclusion, feed processing independently had a significant effect on the availability of pea nutrients. Pea is a good source of both energy and protein and that it can be partially or completely included to replace wheat and soybean meal in poultry diets. However, the effect of SDS on amino acid sparing could not be confirmed. Further research is needed to examine other feed processing techniques, pea cultivars, level of inclusion, and to understand other metabolism responses to feeding SDS from pea.

Three experiments were conducted to determine the efficacy of an <i>Escherichia coli</i> 6-phytase (Quantum phytase) in laying hens fed corn-soybean meal based diets. In experiment 1, the Escherichia coli 6-phytase (Quantum) was evaluated for its efficacy in a 40-wk laying hen production trial. A total of 1080 White Leghorn hens were fed mash corn-soybean meal (CSM) based diets containing 0.35%, 0.25% or 0.15% of non-phytate phosphorus (NPP) with the 0.25% and 0.15% diets containing 200, 400 and 600 U/kg of exogenous phytase. Only minor differences in production characteristics were found between the 0.35% and 0.25% treatments regardless of phytase addition, indicating that 0.25% NPP resulted in P intake that was at or above the hens requirement. In contrast, the hens fed the 0.15% NPP diet without phytase supplementation had significantly reduced production performance in comparison to the 0.35% treatment. The addition of phytase to the 0.15% diet improved these production characteristics to levels equal to or better than the 0.35% diet. The results indicated that Quantum phytase was efficacious in CSM-based diets fed to White Leghorn laying hens and can be used to reduce the need for diet supplementation with inorganic phosphorus. In experiment 2, the effect of Quantum phytase on nutrient digestibility and bone ash in laying hens fed CSM-based diets was investigated. A total of 108 White Leghorn hens were fed CSM-based diets containing 0.35%, 0.25% or 0.15% NPP with the 0.25% and 0.15% diets containing 200, 400 or 600 U/kg of exogenous phytase. A linear reduction in phytate digestibility, ileal protein digestibility and soluble P was reported with increasing levels of exogenous phytase in the 0.25% diet. Tibial bone ash percentage was higher in 61-wk-old hens fed 0.25% diets supplemented with 200 or 400 U/kg phytase. Overall, the Quantum phytase was not efficacious in improving nutrient digestibility in laying hens fed CSM-based diets deficient in NPP. In experiment 3, the impact of dietary Ca and P level on the efficacy of an E. coli-derived 6-phytase and the apparent digestibility of various nutrients was investigated in White Leghorn laying hens fed CSM-based diets. A total of 384 White Leghorn hens were fed CSM-based diets containing four levels of Ca (2.5, 3.5, 4.5 or 5.5%), two levels of NPP (0.15 or 0.30%), and two levels of phytase (300 or 600 U/kg feed). Increasing dietary Ca caused a decrease in AMEn, duodenal protein digestibility, Ca and phytate digestibility, percentage soluble P in feces and the percentage of poor quality eggs, while significantly increasing bone ash and hen-housed and hen-day egg production. The higher level of NPP (0.30%) decreased AMEn, fecal protein, Ca and P digestibility, and hen-housed and hen-day egg production, while increasing fecal soluble P and egg specific gravity in comparison to the lower NPP level. The higher level of dietary phytase (600 U/kg feed) significantly increased AMEn, phytate and P digestibility, soluble P in feces, and hen-day and hen-housed egg production, while significantly reducing the percentage of soft shelled, cracked and broken eggs. Overall, dietary phytase, Ca and NPP levels, either as main effects or in an interactive manner, can affect apparent nutrient digestibility and production traits in laying hens fed CSM-based diets.