Document Type

Thesis - University Access Only

Award Date

2005

Degree Name

Doctor of Philosophy (PhD)

Department / School

Biology

Abstract

Experiments were conducted with the objective of evaluating factors that affect the nutrient digestibility in weanling and growing pigs. Experiment I was conducted to elucidate the effect of the antimicrobial, Carbadox on the porcine small intestinal structure. Pigs on treatment group I received a diet without any in-feed antibiotic (AB-). Pigs on treatment group 2 received the same diet with an antibiotic (Carbadox) included at 50 ppm (AB+). Regardless of the site of sampling, there was no effect of addition of carbadox to the diet on villus height in the small intestine. Likewise, there were no differences in crypt depth values between sites in the small intestine and between diets. No effects of time, diet, or intestinal location were found for the mitotic index. Four other experiments were conducted to measure ileal digestibility coefficients of amino acids using pigs that were equipped with a T - cannula in the distal ileum. Chromic oxide was the inert marker in the diets for all the experiments. For experiment 2, the effect of time after weaning on the apparent ileal digestibility of starch and amino acids were assessed in diets containing three different protein sources. The results of this experiment showed no effect of time after weaning on the digestibility of nutrients. For experiment 3, the effect of feed intake on the apparent and standardized ileal digestibility coefficients was measured in an experiment utilizing six growing barrows. Experimental diets were fed at a level calculated to equal the maintenance requirement of the pig (Ml), at two times the maintenance (M2), and at three times the maintenance requirement (M3). Increasing the feed intake increased the apparent ilea! digestibility coefficients, but reduced the endogenous losses of amino acids, and therefore, also reduced the standardized ileal digestibility coefficients. The objective of experiment 4 was to evaluate the effect of processing on the digestibility of amino acids in blood cell products by grower pigs. Five barrows (initial BW: 41.4 ± 3.1 kg) were used in this experiment and the apparent and standardized ilea! digestibility coefficients were measured in three sources of blood cells and in casein (BCI, BC2, and BC3). Results of this experiment showed that there is a significant effect of spray drying on the digestibility of amino acids in blood cells. These results led to the recommendation that peroxide should not be used to process blood cells. The effect of the in-feed acidifier Aciprol on AA digestibility in grower pigs was assessed for experiment 5. Results from this experiment revealed that the positive effects of acidifiers that have been reported in other experiments are not caused by an increase in the ilea! digestibility of dietary amino acids.

Key Words: Acidifier, Amino acids, Antimicrobials, Digestibility, Pigs, Processing.

Library of Congress Subject Headings

Swine -- Feeding and feeds

Amino acids in animal nutrition

Anti-infective agents

Format

application/pdf

Number of Pages

172

Publisher

South Dakota State University

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