Evaluation of Unheated, Low Trypsin Inhibitor, Full-fat Soybeans on Feed Digestibility and Growth Performance of Turkeys at Various Ages
General Material Designation
[Thesis]
First Statement of Responsibility
Evans, Caitlin E.
Subsequent Statement of Responsibility
Dunphy, Edward
.PUBLICATION, DISTRIBUTION, ETC
Name of Publisher, Distributor, etc.
North Carolina State University
Date of Publication, Distribution, etc.
2020
GENERAL NOTES
Text of Note
114 p.
DISSERTATION (THESIS) NOTE
Dissertation or thesis details and type of degree
M.Sc.
Body granting the degree
North Carolina State University
Text preceding or following the note
2020
SUMMARY OR ABSTRACT
Text of Note
The objective of this research was to evaluate new lines of soybeans (SB), naturally selected to contain low anti-nutritional factors such as trypsin inhibitors (TI) and oligosaccharides (OLG) and to determine their potential as a feedstuff for turkeys. These novel SB would, in theory, require little to no processing prior to diet inclusion; in contrast to traditional soybean meal. Consequently, it may be economical to simply incorporate rolled unheated, full-fat SB into poultry feeds as a major source of both protein and energy. Questions, however, arise as to the nutritional availability of energy and amino acids to the bird. A total of four trials were conducted to evaluate and clarify the bioavailability of nutrients when formulating with these novel low trypsin inhibitor (LTI) soybeans. The initial trial was designed to evaluate 2 novel lines of soybeans: low OLG and low TI (LO) and low TI (LT) for their effect on the growth performance of male turkeys reared from 4 to 19 weeks of age. Poults were reared on pine shavings (PS) or chopped Miscanthus grass (MG). Toms fed diets containing either line of novel SB (LO or LT) had increased BW and FI with a lower overall FCR when compared to birds fed diets with containing commercial SB (CB). Those birds fed the LO or LT also had comparable overall FI when compared to those fed a soybean meal-based diet (SBM), although their BW were lighter the FCR was greater. From this trial it was concluded that LTI SB could be included into turkey rations, but to a limited extent. MG, when used as a litter material through tom market age, resulted in similar growth performance compared to traditional PS, indicating its validity as an acceptable source of poultry bedding. Trials 2 and 3 evaluated the effect of age on the digestibility of the LTI soybean. Poults began treatments at 0 or 14 days. There were 6 dietary treatments: commercial SB (CB) included at 20 or 40%, commercial soybean meal (SBM), and LTI SB included at 20, 30, or 40%. In Trial 2, increasing LTI from 0 to 40% linearly decreased poult BW and FI from 0 to 14 days, while increasing the FCR when compared to SBM; indicating the TI was still present at levels sufficient to affect the protein digestibility. Performance was improved in trial 3. At day 21, there was only a tendency for reduction in BW with linearly decreasing FI, though no significant difference in FCR. By 28 days, LTI diets remained comparable to SBM in BW, FI, and FCR; indicating that as the poult aged, it was more able to utilize the nutrients in the LTI diets for growth. When comparing CB to SBM or LTI diets, performance was consistently reduced when feeding CB. Trial 4 evaluated the effect of feed processing on the digestibility of the LTI soybean. Dietary treatments were: soybean meal (SBM), LTI bean included at 20 or 40%. Each of the diets was fed as mash or crumbled pellet. Iincreasing LTI resulted in a linearly reduction of BW with poults consuming crumbles gaining more weight than those consuming mash. LTI inclusion had no effect on FCR at day 21, while crumbled diets had better FCR as compared to mash diets. Based on the results of these trials, LTI soybeans are a viable ingredient for use in turkey diets. Its effectiveness as an ingredient is improved by feed processing, as shown through improved performance after pelleting. Additionally, the ability of the novel low TI bean to improve PDI without limiting bird growth and performance further increases its value as a feedstuff.