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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.

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Production of ammonia N, a-amino N, and peptide N was investigated following in vitro ruminal incubation of solvent soybean meal (SBM), dehydrated alfalfa, corn gluten feed, fish meal, distillers dried grains with solubles (DDG), cotton seed meal, brewers fried grains, meat and bone meal, blood meal, prolac, and casein (CAS). The influence of milling procedures on the production of ammonia N, a-amino N, and peptide N was also evaluated using different batches of soybean meals and distillers dried grains with solubles. The concentrations of peptide N and ammonia N measured in the cell free media at 0, 2, 4, 6, and 8 h were increased linearly (P < 0.001) with time. The mean concentrations of a-amino N were lower (P < 0.05) than the mean concentrations of peptide N and ammonia N. Production of peptide N, a-amino N, and ammonia N were varied (P < 0.05, time x protein) between proteins and between batches. Irrespective of the protein used, the amino acid composition of peptides (<3,000 MW) that appeared at 8 h had specific patterns suggesting differential utilization of peptides by ruminal microorganisms. Cell-free supernatants obtained following incubation (8 h) of SBM, CAS, and DDG were used as mucosal substrates in parabiotic chambers to quantify absorption of free and peptide-bound amino acids via ruminal and omasal epithelia of sheep. Serosal appearance of amino acids in peptide form was nearly three times higher (P < 0.001) than free amino acids. On tissue dry weight basis, serosal appearance of amino acids was greater (P < 0.01) across omasal than via ruminal tissues. There was a greater serosal appearance of amino acids from CAS than from SBM. Total, total essential (EAA), total nonessential (NEAA), and individual amino acid appearance in serosal fluids varied (P < 0.05, amino acid form x protein source) among SBM, CAS, and DDG. Collectively, these results indicate that the forestomach epithelia of sheep possess the potential to absorb ruminally derived peptides (relatively large amounts) and free amino acids (relatively small amounts). Also, the ruminal microbial degradation of dietary proteins may influence the amounts and types of free and peptide-bound amino acids absorbed via forestomach. / Ph. D.

Forty-six barrows fitted with steered ileo-cecal valve cannulas were used in four experiments to evaluate the effects of supplementing swine diets with microbial phytase or beta-mannanase on the apparent ileal (AID) and/or apparent total tract digestibility (ATTD) of amino acids, N, Ca, P, DM and energy. In Exp. 1, the addition of phytase to low CP corn-soybean meal based diets increased the AID of Ca (P < .01), P (P < .001), and all amino acids (P < .10) measured except Leu, Ser, Pro, Met, His and Tyr. In Exp. 2, the addition of microbial phytase to corn-soybean meal, corn-soybean meal-wheat middlings, or corn-soybean meal-meat and bone meal based diets resulted in increased AID of Ca and P, but had no effect (P > .1) on amino acid digestibilities. Diet type affected all digestibility measurements, but did not affect the efficacy of supplemental phytase. In Exp. 3, the addition of microbial phytase to corn-wheat-soybean meal, corn-wheat-cannola, or sorghum-corn-soybean meal based diets led to an increased ( P <.05) AID of P, Asp, Thr, Ser, Ala, Tyr, Phe, Lys and Arg. In Exp. 4, the addition of beta-mannanase to corn-soybean meal based swine diets led to an increased AID of DM and ATTD of energy. In addition, the AID of all amino acids measured were increased numerically, with many of these values approaching significance. The results of these studies demonstrate that supplementing pig diets with phytase or beta-mannanase, results in an increased digestibility of certain dietary components due to the breakdown of anti-nutritive compounds in the diet. / Ph. D.

This study was conducted to investigate the efficacy of phytase for improving the nutrient utilization for pigs and poultry. Two experiments, one with broilers and one with pigs, were conducted to compare the efficiency of transgenic microbial (Natuphosà ) and plant (Phytaseedà ) phytase for enhancing the utilization of phytate P in corn-soybean diets fed to young broilers and pigs, and to evaluate the safety of Phytaseedà phytase. Three levels of the two sources of phytase (250, 500 and 2,500 U/kg of diet) were added to a corn-soybean meal basal diet containing 0.21 and 0.26% nonphytate P, respectively, for broilers and pigs. Forty birds and thirty pigs (8 broilers and 6 pigs, one per cage, from the diet without added phytase and the diets with 500 or 2,500 U/kg phytase from both sources) were randomly selected for gross necropsy and histologic evaluation of liver, kidney and bone tissues. Adding both sources of phytase to the basal diet resulted in similar increases of BW, BW gain, feed intake, gain:feed, apparent digestibilities (retention) of DM, P and Ca, and bone measurements. Phosphorus excretion decreased as phytase addition increased. No significant abnormalities were seen in any of the broilers and pigs necropsied. In a study with pigs (n=120 and 80, respectively for grower and finisher), the effects of supplemental microbial phytase on crude protein and amino acid utilization of low protein plant-based diets was investigated. During the grower period (32 to 67 kg), diets 1, 2 and 3 contained 14, 13 and 12% crude protein and no added phytase, respectively, and diets 4 and 5 contained 12% crude protein with either 250 or 500 U of phytase/kg of diet, respectively. During the finisher period (67 to 109 kg), diets 1, 2 and 3 contained 12, 11 and 10% crude protein with no added phytase, respectively, and diets 4 and 5 contained 10% crude protein with either 250 or 500 U of phytase/kg of diet, respectively. At the end of grower phase, two pigs (1 barrow and 1 gilt) were removed from each pen; 12 of the barrows that were removed from diets 1, 3 and 5 were put in metabolism cages for total collection, and the remaining four pigs in each pen continued on test for the finisher phase. At the end of finisher phase, 12 barrows from diet 1, 3, and 5 were put in metabolism cages for total collection. Ileal contents were taken (slaughter technique) from the remaining barrows and the barrows used in metabolism cages. Daily gain increased as protein and phytase levels was added to the lowest protein level. Fecal P and Ca digestibilities improved with added phytase. Phytase addition to basal diet linearly increased ash weight in the grower phase. With the exception of proline and glycine, the digestibilities of the other amino acids were linearly increased with phytase and CP level. Nitrogen excretion was estimated to be reduced by 4.6% when phytase was added to pig diets at a level of 500 U/kg. In a study with cecectomized roosters, the main effects and interaction of phytase and non-startch polysaccharide enzymes on the nutrient utilization of barley, canola meal, rice bran and soybean meal, and canola-barley (36:64) and soybean meal-barley (27.3:72.7) were evaluated. Phytase supplementation to basal diets increased the utilization of energy, N, total amino acid and most of amino acids in barley, canola meal, and canola-barley and numerically increased energy and N utilization in rice brain, soybean meal and soybean-barley. The magnitudes of improvements in the digestibilities of lysine, arginine, cysteine, serine, and threonine were higher compared with the other amino acids. The true utilization of energy and N, and the digestibilities of total amino acid and of glycine, isoleucine, and histidine in barley quadratically increased with Ronozyme™ B. Phytase addition increased Ca retention in barley, canola and soybean meal, and the soybean meal-barley blend, and increased P retention in barley and soybean meal-barley. Addition of Ronozyme™ B to barley linearly decreased Ca retention and quadratically increased P retention. In summary, the efficiency of phytase in Phytaseed is equal to that of Natuphos for enhancing the utilization of phytate P in corn-soybean diets, and microbial phytase is effective in improving the utilization of N and amino acid in pigs and N, amino acid, and energy in poultry. / Ph. D.

Dairy cows inefficiently convert dietary protein to milk protein causing economic and environmental costs. Amino acids (AA), insulin, and glucose significantly enhance muscle protein synthesis efficiencies. The objectives of this research project were 1) to investigate the regulatory effects of essential AA (EAA) and their interactions with insulin, glucose and acetate on mammary protein synthesis rates, 2) to investigate whether branched chain amino acids (BCAA): leucine , isoleucine , and valine , become limiting for milk protein synthesis when Met and Lys supply were not limiting, and 3) to develop a mathematical representation for the EAA and insulin effects on cellular signals for protein synthesis. MAC-T cells were treated with EAA, insulin, glucose, and acetate to observe their individual and interactive effects on phosphorylation of mTOR, rpS6, S6K1, 4EBP1, eEF2, eIF2α, Akt, and AMPK. These signaling effects on protein synthesis rates were examined with mammary tissue slices. A mathematical representation of the insulin and EAA effects was developed. The effects of supplementing BCAA on milk protein synthesis were investigated using nine Holstein cows, assigned to 7 d continuous jugular infusions of saline, Met and Lys, and Met and Lys plus BCAA. Multiple essential amino acids, Leu, Ile, Met, and Thr were able to substantially regulate protein synthesis rates in bovine mammary cells by increasing (P < 0.05) phosphorylation of mTOR, S6k1, 4EBP1, and decreasing (P < 0.10) eEF2 phosphorylation. Insulin considerably (P < 0.10) exerted similar signaling effects in MAC-T cells, independent of EAA. Supplementation of only acetate increased (P = 0.09) mammary cell energy status as indicated by reduced AMPK phosphorylation in MAC-T cells. Neither acetate nor glucose had substantial regulatory effects on mammary protein synthesis rates. Although Met and Lys supplementation increased (P < 0.01) milk protein yields and protein efficiencies, there were no apparent benefits of BCAA supplementation under the feeding circumstances of our study. The developed mathematical model adequately represented the regulatory effects of EAA and insulin. Such mathematical representations of regulatory effects of EAA and their interaction with other nutrients may improve our current AA requirement models to predict AA requirements of dairy cows with increased accuracy. / Ph. D.

The objectives of these studies were to assess U.S. dairy nutritionists' approaches toward balancing CP in lactating cow diets, and to leverage existing knowledge of postabsorptive AA metabolism through the application of a mathematical ration-balancing model to predict N efficiency through a more accurate postabsorptive amino acid (AA) delivery. In experiment 1, dairy nutritionists (n = 77) that fed a total of 521,000 lactating dairy cows responded to a questionnaire related to demographic information, feelings toward environmental nitrogen (N) excretion, and dietary CP balancing practices. Eighty-nine percent of nutritionists balanced diets based on one or more individual AA requirements of dairy cows. The primary concern with formulation of lower CP diets was the cost per unit of metabolizable protein (MP). In the second study, three treatments were fed to lactating Holstein cows (n = 48) to test proof of concept of NASEM 2021 and a nonlinear optimizer: a control balanced to fulfill all nutrient needs of lactating dairy cows producing 45 kg milk/d using the NRC (2001) dairy model (NRC01), and two diets balanced with a nonlinear optimizer that fulfilled requirements according to the updated NASEM (2021) dairy model and attempted to either: 1) maximize N efficiency through tailored post-ruminal AA supply (NEFF), or 2) maximize income over feed cost (IOFC). A simulation function was written in RStudio (version 2022.02.3) to predict daily animal performance with NASEM 2021. Dry matter intake, milk, and milk components from both the observed data and the simulation data matrices were analyzed as repeated measures (days) in a mixed model to test for both observed and predicted (simulated) differences in treatment means. Income over feed cost was $4.83, $4.77, and $5.12/cow/d for NRC01, IOFC, and NEFF, respectively (P = 0.96). Nitrogen efficiency (%) was greatest for NEFF (33.7), followed by NRC01 (28.9) and IOFC (23.4; P < 0.05 between all treatments). Based upon simulation data, NASEM 2021 predicted relative performance differences between animals that consumed treatments with differing absorbed EAA supplies, although residual analyses revealed that further progress could be made in milk protein (g/d), milk fat (g/d), milk yield (kg/d), and DMI (kg/d) predictions. / Doctor of Philosophy / Nitrogen (N) is considered one of the major environmental pollutants of the dairy industry. A concerted focus on reducing dietary crude protein (CP) loss by targeting the specific amino acid (AA) needs of cattle will also reduce the amount of N they excrete. Because most dairy farmers hire nutritionists to formulate rations for their cows, the objective of our first study, performed in 2019, was to assess U.S. dairy nutritionists' approaches toward balancing AA in lactating cow diets. The objective of our second study was to apply a mathematical ration-balancing model that specifically optimized AA efficiency for lactating dairy cows by leveraging existing knowledge of dairy cow AA metabolism. In study 1, 89% of nutritionists balanced diets based on one or more individual AA requirements of dairy cows. Most respondents (72%) reported that they are currently formulating diets with lower dietary protein than they were 3 to 5 yr ago. In the first study, the primary concern with formulating lower protein diets was the high cost of protein sources that are highly metabolizable for cows. In study 2, income over feed cost (income made from estimated milk sales minus cost of feed) was similar for cows fed a diet with the lowest protein (relative to two other diets), but cows on the low protein diet also ate the least (kg of dry matter/d) and produced the least amount of milk protein (kg/d) and milk fat (kg/d). Still, relative to the other two diets in the study, N consumed by cows on the lowest CP diet was more efficiently converted to milk protein, which resulted in lesser N excretion in milk. Harnessing the knowledge gained from these studies could allow significant reduction of environmental N excretion at little to no cost to consumers or farmers.

A new approach in the syntheses of 3-bromo-2-butanone and 2-bromo-3-fluorobutane has been developed. All attempts to alkylate the sodium salt of diethyl malonate, ethyl acetoacetate, or diethyl acetamidomalonate with 2-bromo-3-fluorobutane failed. New phosphonoacetates, tert-butyl and benzyl diethylphosphono-acetates were prepared as very versatile intermediates in the syntheses of carboxylic acids. Methyl-, ethyl-, tert-butyl-, and benzyl 4-fluoro-3-methyl-2-pentenoates were synthesized in high yields by the Horner-Emmons reaction. The reaction is stereoselective and gave E and Z form in 75:25 ratio as determined from proton and fluorine nmr spectra. A long-range coupling was observed in fluorine nmr spectrum of 3-fluoro-2-butanone. From the ethyl 4-fluoro-3-methyl-2-pentenoate, ethyl 2-bromo-4-fluoro-3-methyl-2-pentenoate was prepared, but the latter could not be reduced under the conditions of catalytic hydrogenation. Ethyl 2-chloro-4-fluoro-3-methyl-2-pentenoate was prepared from 3-fluoro-2-butanone and ethyl diethylphosphonochloroacetate, but could not be reduced. Catalytic hydrogenation of alky 4-fluoro-3-methyl-2-pentenoates gave the corresponding saturated esters in high yields. Treatment of alkyl 4-fluoro-3-methylpentanoates with lithium diisopropylamide and bromine at -78° yielded the corresponding 2-bromoderivatives. Methyl-, ethyl-, and tert-butyl 2-bromo-4-fluoro-3-methyl-pentanoates were treated with sodium azide to give the corresponding 2-azido derivatives which were further reduced into methyl-, ethyl-, and tert-butyl 2-amino-4-fluoro-3-methylpentanoates. / Ph. D.