AN ABSTRACT OF THE THESIS OF David Williams for the Master of Ruminant Nutrition degree in Animal Science, presented on December 12, 2016 at Southern Illinois University Carbondale. TITLE: IN VITRO APPARENT RUMINAL DIGESTIBILITY OF DIETS CONTAINING CORN DISTILLERS GRAIN WITH VARYING LEVELS OF CRUDE FAT MAJOR PROFESSOR: Dr. Rebecca Atkinson
 Four dual-flow continuous fermenters were used in a Latin square design to determine the apparent ruminal digestibility and ruminal characteristics of diets containing dried distillers grains plus solubles (DDGS) at various levels of fat content. Fermenters were randomly assigned to one of the following treatments: 1) 40% DDGS containing 4.82% fat content (40 LOW); 2) 40% DDGS plus corn oil to obtain 7.5% fat (40 MED); 3) 40% DDGS plus corn oil to obtain 10.5% fat (40 HIGH); or 4) 70% DDGS plus corn oil to obtain 7.5% fat (70 MED). Rumen fluid was collected at the beginning of each period from two ruminally cannulated Angus cows previously adapted to the 40LOW treatment. Each period consisted of 10 days with a seven day adaptation period followed by three days of sample collection. Calories per gram of diet increased as percent fat increased and calories per gram was greater at the 70% inclusion of DDGS compared to 40% inclusion of DDGS at all levels of fat content. However, level of fat in the diet did not influence (P ≥ 0.35) apparent ruminal digestibility of DM, NDF, ADF, CP or total calories. Similarly, inclusion rate of DDGS had no influence (P ≥ 0.35) on nutrient digestibility. Ammonia concentrations were greatest (P = 0.0002) for 70 MED compared to the other treatments. However, treatment had no impact (P ≥ 0.16) on volatile fatty acid production with the exception of propionate which increased (P =0.05) as the level of DDGS increased from 40 to 70% inclusion rate. This data would suggest that level of fat content of DDGS has no negative influence on apparent ruminal digestibility and select ruminal characteristics. From an economic perspective, higher fat DDGS should have a higher price differential, but lower fat DDGS can still be an effective protein and energy substitute.

Dietary composition can impact colonization and composition of gut microbiota. The first aim of this dissertation was to evaluate the effect of dietary Se deprivation, sex and, aging on taxonomic composition of gut microbiota in mice. We have previously shown that long-term dietary Se deprivation promotes health span deteriorate including type-2 diabetes like symptoms in later state Terc-/- mice carrying humanized telomeres. In the present study, the data suggested that the dietary Se deprivation and aging significantly and comparably altered the gut microflora composition. The ratio of Firmicutes/Bacteroidetes was decreased by dietary Se deprivation or aging in both sexes. Abundance of selective gut bacteria genus was associated with dietary Se status and aging as evidenced by heat map and principal coordinate analyses. Moreover, the abundance of Akkermensia muciniphila, a bacterium in association with obesity, differed by Se-deprivation, aging and sex. Taken together, changes in gut microbiota composition by dietary Se deprivation may accelerate mouse aging in a sex-specific manner. The second aim of this dissertation was to investigate the effects and underlying mechanism of fecal fermentation of non-digestible fibers isolated from common beans on adipocyte differentiation and fat accumulation to elucidate the cellular mechanisms. Treatment of 3T3-L1 murine preadipocytes with fermented product resulted in a reduction of triglyceride accumulation in a dose- and time-dependent manner. The fermentation product exhibited antiipogenic effects through suppression of the adipogenesis-associated key transcription factors or activators peroxisome proliferator-activated receptor gamma (Ppar gamma), CCAAT enhancer-bind protein alpha (C/ebp alpha) and fatty acid binding protein 4 (Fabp4). Moreover, the mRNA expression lipolytic genes including peroxisome proliferator-activated receptor delta (Ppar delta) and mitochondrial uncoupling protein 2 (Ucp2) were induced by the fermentation products of non-digestible fiber isolated from common beans counteract adipogenesis through regulation of key targets.Altogether, optimizing gut microbiota by nutritionally adequate level of dietary Se and non-digestible fiber appears to represent a promising strategy to control or prevent early onset of aging and age-related metabolic diseases.

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Previous research evaluated the dLys requirement and the impact of varying dLys and AME on Cobb MV x Cobb 500 broilers during the starter and grower phases, leaving the finisher phase to be determined. Experiment 1 estimated the finisher dLys requirement to range from 0.748-1.32% for males and 0.752-1.292% for females. Male broilers were more responsive to increasing dLys than females, though in general, increasing dLys improved performance and processing. Experiment 2 determined the effects of varying finisher dLys and AME on broiler performance and processing. Increasing dLys improved BWG, FCR, ALI, and breast yield while decreasing FI and fat pad yield. Increasing AME consistently reduced FI and FCR while increasing thigh and fat pad yield. Economic analyses for both experiments demonstrated that maximizing performance was not always economical, verifying the importance of considering feed costs and performance to optimize return on investment for Cobb MV x Cobb 500 broilers.

The purpose of this study was to compile practical feeding guidelines for donkeys in the UK. Current guidelines are to feed 0.75 of horse feeding recommendations on a body weight basis. However, the superior digestive efficiency of donkeys, compared to horses, may render the use of horse recommendations inappropriate. The formulation of guidelines specific to donkeys would enable owners to calculate their donkey‟s requirements with greater accuracy and prevent overfeeding. A postal survey, used to gain information on the body condition score of donkeys in the UK, and the husbandry and feeding practices used to manage them, indicated that approximately 24% of donkeys in the UK are overweight. Feeding practices indicated that although owners were aware of their donkey‟s requirement for fibrous forages, the practice of feeding unnecessary concentrates, chaffs and high energy forages, in addition to grazing, was the likely cause of donkeys becoming overweight. The finding that the majority (85 – 90%) of donkeys were kept as non-working companion animals also reduced the need for owners to feed higher energy foods to their donkeys. Results also suggested that owners were unsure of how to adjust their donkey‟s diet to account for seasonal changes in requirements and pasture availability, as most owners‟ adjusted grazing access, and not the feeding of supplementary feeds. From a study of dry matter (DM) and digestible energy (DE) intakes by 20 mature donkeys maintaining weight during each UK season, the maintenance DE requirements of donkeys were calculated. Results showed no effect of sex on DM or DE intake. Season significantly (P<0.001) affected DM and DE intakes, implying increased requirements in winter compared to spring, summer and autumn. Dry matter intakes (DMI) increased from 51g/kg BW0.75 in spring, summer and autumn to 66g/kg BW0.75 in winter. Digestible energy requirements increased from 0.32MJ/kg BW0.75 in spring, summer and autumn to 0.43MJ/kg BW0.75 in winter. Comparison of results with horse recommendations showed considerably reduced requirements by donkeys. Horse recommendations overestimated DE requirements in summer and winter by 82 and 30%, respectively, making horse recommendations unsuitable for calculating donkey energy requirements. Husbandry practices commonly used by owners to manage their donkeys grazing access (grazing time, grazing area, strip grazing), were assessed for their effect on DMI by grazing donkeys in summer and autumn, using n-alkanes. The effect of grazing time was assessed by restricting donkeys to 8, 12 or 23 hours grazing per day. Season significantly affected food intake with donkeys in the 8 and 23 hour grazing groups eating more during summer when pasture availability was greater. Donkeys responded to the poorer quality summer pasture by grazing more intensively but less selectively, increasing the rate at which food was consumed. Grazing time was only influential over grass intake in summer, when pasture was more abundant. Restricting donkeys to 12 hours or less grazing per day significantly (P<0.001) reduced their grass intake compared to that of donkeys with 23 hours access. When grazing sparse pastures (autumn), grazing time did not influence grass intake, indicating an effect of herbage mass on grazing behaviour. Herbage mass was the most influential factor over diet composition (percentage of grass and straw consumed) in a second grazing study assessing the affect of strip grazing and set stocking systems on intake by grazing donkeys during summer and autumn. Herbage mass per donkey was higher in the set stocking system during both seasons, resulting in higher grass intakes. Determining if either grazing system was more effective at regulating grass intake was prevented due to differences in pasture availability between study sites. It is concluded that donkeys have lower DMI and maintenance DE requirements than horses, requiring donkey feeding guidelines to be formulated. Excess body weight in donkeys is caused in part, by the feeding of energy dense feeds in addition to low energy forages. Most owners place little nutritional importance on pasture, despite its potential to provide a large percentage of daily DM, DE and nutrient intake. Therefore nutritional guidelines must include advice on how to manage access to grazing, and how to feed donkeys with access to pasture. Restricting grazing time to 8 hours a day did reduce grass intake by donkeys, but was only effective when grazing abundant pastures. Providing ad libitum straw to grazing donkeys allows them to satisfy their DM and dietary fibre requirements without consuming excess energy.

The objective of these studies was to develop near-infrared reflectance spectroscopy calibration equations from diet-fecal pair datasets to predict the diet quality and intake of donkeys. One hundred-forty diet-fecal pair samples were generated from two independent in vivo feeding trials conducted in the United States (N = 100) and Africa (N = 40). At each site, ten female donkeys were fed mixed diets blended from 25 forage and crop residues. The modified partial least square model (MPLS) was used to develop calibration equations for crude protein (CP), digestible organic matter (DOM), dry matter digestibility (DDM) and organic matter digestibility (OMD), for the US, Africa and US/Africa combined datasets, and dry matter (DM) and organic matter (OM) intake calibrations from the US datasets. Crude protein (CP) equations were developed with standard error of calibration (SEC) < 1.0 and coefficient of determination (R2) > 0.90, (SEL = 0.5). The US, US/Africa and Africa CP equations had SEC value of 0.77, 0.97 and 0.88 with corresponding R2 of 0.97, 0.95 and 0.88, respectively. Validation of the US CP equation resulted in a standard error of prediction (SEP) of 1.79 with corresponding coefficient of correlation (r2) of 0.82 and slope of 0.84 indicating high accuracy of prediction. In vivo derived DOM equations were also developed for the US, Africa and US/Africa datasets with SEC values of 2.58, 4.91 and 3.52, and R2 of 0.60, 0.81 and 0.84, respectively. In addition, the SEC and R2 values were 3.25 and 0.72 for US OMD, 3.28 and 0.79 for US DDM, and 4.2 and 0.85 for US/Africa OMD, and 4.3 and 0.87 for US/Africa DDM equation, respectively. Calibration equations for predicting DMI and OMI have resulted in SEC values of 3.45 and 3.21 (g/kgw0.75) and R2 values of 0.89 and 0.84, respectively. The present study explored the relationship between DMI and diet quality attributes. Crude protein and digestible organic matter to crude protein ration (DOM/CP) with r2 values of 0.60 and 0.39, respectively, have shown good correlations with intake. The present studies have confirmed the potential for the fecal NIRS profiling for predicting CP, DOM, DDM, OMD, DMI and OMI of donkeys. Both calibration and validation results have indicated that the present donkey equations were comparable to previously developed equations for ruminants; they have the capability for accurate prediction of diet quality and intake, and can be a useful tool for monitoring the nutritional well-being of donkeys with acceptable accuracy. Research works to further expand the present calibration equations with additional diet-fecal samples particularly from Africa that did not meet the required accuracy level is recommended.

Sorghum (Sorghum bicolor (L). Moench) is used for human consumption in parts of Africa and Asia and as an animal feed mainly in the U.S. Though sorghum grain contains higher amounts of protein than other cereal grains such as wheat and corn, it is not as readily available for enzyme degradation in humans and animals. Protein body matrices called kafirins surround the starch granules in sorghum. Because the protein is less digestible, the starch is also less digestible for biofuel production. However variation for this trait exists and the line P850029 has a higher protein digestibility compared to other normal grain sorghum lines. This increase in digestibility of protein is due to the rearrangement of the kafirins in the prolamin protein bodies where, the γ-kafirins are rearranged in the seed endosperm and the amount of γ-kafirin in the grain is also reduced. The assay to phenotype the HD trait is time consuming and unpredictable. So identifying a quantitative trait loci (QTL) controlling the protein digestibility trait in sorghum would be beneficial in breeding. A recombinant inbred lines (RILs) population derived from P850029 x ‘Sureno’, were developed and used to map QTL regulating the protein digestibility trait. A single QTL was identified on chromosome 1 between Xtxp43 and Xtxp329. Validation of the identified QTL was done on heterogenous inbred families (HIFs). The results validate the same QTL identified on the RIL population on chromosome 1. Later the high digestibility trait (HD) was integrated with the Waxy trait in sorghum. The Waxy (WX) sorghums have starch completely in the form of amylopectin. The effect of endosperm type on ethanol yield and fermentation efficiencies was studied among HD, WX and HD-WX lines. The HD-WX lines fermented in a shorter time i.e. completed fermentation in 48 h and their fermentation efficiencies were also higher around 90%. The DDGS of the HD-WX lines also had lower residual starch content and 50% higher amino acid lysine content when compared to wildtype sorghum. Moreover, the relation between endosperm traits and grain yield in sorghum has not been fully explored. In this study, we compared the yield and yield components of four unique endosperm phenotypes, HD, WX, HD-WX and wildtype lines. A total of 100 F2:4 derived recombinant inbred lines population from a cross between Tx2907/P850029 were selected with 25 lines from each HD, WX, HD-WX and wild-type line were included in the study. These lines were grown in three replications in College Station and Halfway, Texas in a randomized complete block design. The results show that there are no significant differences in the grain yield.

The potential of high digestible grain sorghum (HDGS) with a modified starch protein endosperm matrix to replace corn in ethanol production was investigated using dry grind simultaneous saccharification and fermentation (SSF). Preliminary experiments showed that HDGS yielded higher amounts of glucose and ethanol than normal digestible grain sorghum (NDGS) and corn particularly in the first 48 hrs of fermentation. It was hypothesized that fast conversion of starch to glucose and ethanol during hydrolysis and fermentation are results of improved protein digestibility of HDGS. The invagination of protein structures in HDGS produced a flourier endosperm texture, softer kernels and lower starch content than the normal digestible protein (ND) lines. Highly digestible protein (HD) lines have better pasting properties (significantly lower pasting temperature, faster rate of gelatinization and higher peak viscosity) than ND lines based on the RVA profile. Increasing protein digestibility of the HDGS improved starch digestibility (increased rate of glucose conversion and total glucose yield during saccharification), which is supported by highly significant correlation of turbidity with rate of glucose conversion and efficiency of enzymatic conversion. The efficiency of ethanol conversion is significantly correlated with starch digestibility, pasting properties, and protein digestibility. Results also showed that HD sorghum lines had significantly faster rate of conversion and shorter reaction time needed to achieve completion than ND sorghum lines and corn. Increasing the dry solid concentration from 22% to 30% (w/v) increased the ethanol yield from 8% v/v to 13%v/v. This will allow considerable saving of water, reduced distillation cost and increased ethanol production for a given plant capacity and labor cost. Fineness of grind influences the amount of sugar formed due to variation in surface area of the flour. The hypothesis that finer particles has faster and higher glucose yield, defined as g of glucose converted per g of theoretical glucose, is supported by highly significant correlation of mass fraction of 3 to 60 mu m size range and mass median diameter (MMD) of 60 to 1000 mu m size range with glucose conversion efficiency and glucose conversion rate during saccharification and fermentation.

The objective of these studies was to develop near-infrared reflectance spectroscopy calibration equations from diet-fecal pair datasets to predict the diet quality and intake of donkeys. One hundred-forty diet-fecal pair samples were generated from two independent in vivo feeding trials conducted in the United States (N = 100) and Africa (N = 40). At each site, ten female donkeys were fed mixed diets blended from 25 forage and crop residues. The modified partial least square model (MPLS) was used to develop calibration equations for crude protein (CP), digestible organic matter (DOM), dry matter digestibility (DDM) and organic matter digestibility (OMD), for the US, Africa and US/Africa combined datasets, and dry matter (DM) and organic matter (OM) intake calibrations from the US datasets. Crude protein (CP) equations were developed with standard error of calibration (SEC) < 1.0 and coefficient of determination (R2) > 0.90, (SEL = 0.5). The US, US/Africa and Africa CP equations had SEC value of 0.77, 0.97 and 0.88 with corresponding R2 of 0.97, 0.95 and 0.88, respectively. Validation of the US CP equation resulted in a standard error of prediction (SEP) of 1.79 with corresponding coefficient of correlation (r2) of 0.82 and slope of 0.84 indicating high accuracy of prediction. In vivo derived DOM equations were also developed for the US, Africa and US/Africa datasets with SEC values of 2.58, 4.91 and 3.52, and R2 of 0.60, 0.81 and 0.84, respectively. In addition, the SEC and R2 values were 3.25 and 0.72 for US OMD, 3.28 and 0.79 for US DDM, and 4.2 and 0.85 for US/Africa OMD, and 4.3 and 0.87 for US/Africa DDM equation, respectively. Calibration equations for predicting DMI and OMI have resulted in SEC values of 3.45 and 3.21 (g/kgw0.75) and R2 values of 0.89 and 0.84, respectively. The present study explored the relationship between DMI and diet quality attributes. Crude protein and digestible organic matter to crude protein ration (DOM/CP) with r2 values of 0.60 and 0.39, respectively, have shown good correlations with intake. The present studies have confirmed the potential for the fecal NIRS profiling for predicting CP, DOM, DDM, OMD, DMI and OMI of donkeys. Both calibration and validation results have indicated that the present donkey equations were comparable to previously developed equations for ruminants; they have the capability for accurate prediction of diet quality and intake, and can be a useful tool for monitoring the nutritional well-being of donkeys with acceptable accuracy. Research works to further expand the present calibration equations with additional diet-fecal samples particularly from Africa that did not meet the required accuracy level is recommended.

Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniversitet, 2005. / Härtill 4 uppsatser.