<p dir="ltr">The objective of this thesis was to evaluate the nutrient digestibility in alternative animal and plant sources of feed ingredients for chickens and pigs. Therefore, 5 studies were carried out to determine the nutrient utilization in poultry meal (<b>PM</b>), faba beans (<b>FB</b>), and 3 cultivars field peas (<b>FP</b>).</p><p dir="ltr">In the first study, 2 experiments investigated the energy and phosphorus utilization of PM for broiler chickens. Poultry meal was used to substitute corn and soybean meal in the reference diet at 0, 80, or 160 g/kg in Experiment 1. Whereas PM was included in the diet at 0, 50, or 100 g/kg in Experiment 2. A total of 192 birds were allotted to 3 experimental diets in both experiments. The estimated ileal digestible energy (<b>IDE</b>), metabolizable energy (<b>ME</b>), and nitrogen-corrected metabolizable energy (<b>MEn</b>) for PM were 4,002, 3,756, and 3,430 kcal/kg DM, respectively. In Experiment 2, the true ileal digestibility (<b>TID</b>) and true total tract utilization (<b>TTTU</b>) of P in PM were 77.5 and 79.0%, respectively.</p><p dir="ltr">The second study consisted of 3 experiments. In the first experiment, 240 birds were assigned to 5 diets to determine the energy values of FB and DS admiral FP (<b>FPD</b>). In Experiment 1, the test ingredients were incorporated into a corn-soybean meal-based diet at 0, 150 or 300 g/kg. The IDE, ME, and MEn for FB were 2,541, 2,628, and 2,394 kcal/kg, respectively. The respective values for FPD were 2,254, 2,540, and 2,331 kcal/kg DM. In each of Experiments 2 and 3, 162 birds were assigned to 3 diets. Faba beans was included at 21, 42, or 63% and FPD at 16, 32, or 48% in Experiments 2 and 3, respectively. The TID and TTTU of P in FB were 66.5 and 66.7%, respectively. The corresponding values for FPD were 73.4 and 73.8%.</p><p dir="ltr">The third study consisted of 3 experiments. In Experiment 1, the energy values for Hampton FP (<b>FPH</b>) and 4010 FP (<b>FP4</b>) fed to broiler chickens were estimated. Two hundred and forty birds were assigned to 5 diets. The test ingredients were included at 0, 150 or 300 g/kg into a corn-soybean meal-based reference diet. With regression analysis, the determined IDE, ME, and MEn were 3,274, 3,033, and 2,850 kcal/kg DM in FPH, respectively, in FP4 the energy values were 3,019, 3,155, and 2,991 kcal/kg DM, respectively. The P utilization in FPH and FP4 were determined in Experiments 2 and 3, respectively. The corresponding TID and TTTU of P in FPH were 74.6% and 68.3%, and 74.3 and 61.7% in FP4.</p><p dir="ltr">Two experiments were conducted in the fourth study to estimate the digestible energy (<b>DE</b>) and ME in FB and FP fed to pigs. Twenty-four barrows were assigned to 3 dietary treatments in each of the experiments. Faba beans or FPD in Experiment 1 and FPH or FP4 in Experiment 2 were included in the diet at 0 or 300 g/kg. The determined DE and ME values for FB using the total collection method were 3,772 and 3,606 kcal/kg DM and in FPD were 3,683 and 3,589 kcal/kg DM, respectively. In Exp. 2, the respective DE and ME for FPH were 4,164 and 4,014 kcal/kg DM and for FP4 were 3,574 and 3,467 kcal/kg DM.</p><p dir="ltr">In the last study, standardized ileal digestibility (<b>SID</b>) of amino acids (<b>AA</b>) in faba beans and three cultivars of FP between broiler chickens and pigs were compared. The test ingredients were the only source of protein providing 160 g/kg crude protein and a nitrogen-free diet was prepared to estimate the basal endogenous losses of AA. The same set of five diets was used across both species. The SID of Lys in FB, FPD, and FPH exceeded 90% but in FP4 it was 85.1% for broiler chickens. Whereas for pigs the SID of Lys in FB, FPD, and FPH exceeded 80% but for FP4 it was 89.8%. The SID of Met in the test ingredients ranged from 72.1 to 89.8% and 68.1 to 81.8% for broiler chickens and pigs, respectively. In general, the SID of AA in the test ingredients were greater compared with chickens. The energy, P, and AA digestibility of the test ingredients determined in the five studies could be used in diet formulation for chickens and pigs.</p>

The association between individual plant performance and seed yield variability within and between field pea crops was investigated. In 1988/89 six F8 genotypes with morphologically distinct characteristics were selected from a yield evaluation trial. Analysis of the individual plant performance within these crops indicated an association between low seed yields and the location and dispersion of plant harvest index (PHI) and plant weight (PWT) distributions. The analyses also showed there was a strong linear relationship between the seed weight (SWT) and PWT of the individual plants within each crop, and that the smallest plants tended to have the lowest PHI values. A series of 20 simulations was used to formalize the relationships between SWT, PWT and PHI values within a crop into a principal axis model (PAM). The PAM was based on a principal axis which represented the linear relationship between SWT and PWT, and an ellipse which represented the scatter of data points around this line. When the principal axis passed through the origin, the PHI of a plant was independent of its PWT and the mean PHI was equal to the gradient of the axis. However, when the principal axis had a negative intercept then the PHI was dependent on PWT and a MPW was calculated. In 1989/90 four genotypes were sown at five plant populations, ranging from 9 to 400 plants m⁻². Significant seed and biological yield differences were detected among genotypes at 225 and 400 plants m⁻². The plasticity of yield components was highlighted, with significant genotype by environment interactions detected for each yield component. No relationship was found between results for yield components from spaced plants and those found at higher plant populations. The two highest yielding genotypes (CLU and SLU) showed either greater stability or higher genotypic means for PHI than genotypes CVN and SVU. Despite significant skewness and kurtosis in the SWT, PWT, and PHI distributions from the crops in this experiment, the assumptions of the PAM held. The lower seed yield and increased variability in PHI values for genotype CVN were explained by its higher MPW and the positioning of the ellipse closer to the PWT axis intercept than in other genotypes. For genotype SVU, the lower seed yield and mean PHI values were explained by a lower slope for the principal axis. Both low yielding genotypes were originally classified as having vigorous seedling growth and this characteristic may be detrimental to crop yields. A method for selection of field pea genotypes based on the PAM is proposed. This method enables the identification of weak competitors as single plants, which may have an advantage over vigorous plants when grown in a crop situation.