Semester

Spring

Date of Graduation

2022

Document Type

Dissertation

Degree Type

PhD

College

Davis College of Agriculture, Natural Resources and Design

Department

Animal and Nutritional Sciences

Committee Chair

Joseph Moritz

Committee Co-Chair

Jacek Jaczynski

Committee Member

Jacek Jaczynski

Committee Member

Cangliang Shen

Committee Member

Jon Ferrel

Abstract

Two experiments were conducted to evaluate a novel throughput agent and its mechanisms on production rate and pellet quality. An additional experiment using lab-based methods and models was conducted to predict Salmonella reduction in mash broiler feed. Feed mill pellet production rate is of great importance to integrated meat bird production. Feed hygienics are also of increasing concern for poultry producers.

In chapter 2, the effect of AZOMITE® (AZM) and varying inorganic phosphate sources (IPS) on pellet mill production rate and pellet quality was assessed. It is documented that the naturally abrasive properties of inorganic phosphate sources may scour the pellet die and affect feed production rate. Inorganic phosphate source use has been on the decline, prompting the use of novel throughput agents such as AZM. The objective was to evaluate the effect of AZM inclusion in a corn, soybean meal, dried distillers grains with solubles (DDGS) based diet with either dicalcium (DCP) or tricalcium (TCP) on pellet mill production rate, hot pellet temperature, and pellet quality. The assessment included 4 experimental treatments in a 2 (DCP or TCP) x 2 (AZM or no AZM) factorial Latin Square Design across four manufacturing days with complete blocks in each day. There was a 6% increase in production rate when AZM was added to DCP diets (0.99 versus 1.05 MT/hr; P<0.001) and an 8% increase in production rate when AZM was added to TCP diets (1.10 versus 1.19 MT/hr; P<0.001). IPS and AZM interacted to affect pellet quality (P<0.021), demonstrating that increased production rate decreased pellet quality.

In chapter 3, the effect of AZM and its fractions on pellet mill production rate and pellet quality was assessed. AZM can be separated into two fractions, a fine and coarse fraction, but the mechanism of how each enacts its effect at the pellet die have not yet been determined. The objective was to assess the response AZM and its two fractions on pellet mill production rate, hot pellet temperature, and pellet quality. One basal diet that was supplemented with AZM and its fractions was manufactured in a Latin Square with crossover design across 4 days. In support with previous research, inclusion of AZM increased production rate 7% when added to the basal diet (0.999 vs. 0.935 MT/h; P=0.005). The combination of both fractions likely contributing both a lubricating and pellet die scouring effect increased production rate more than either single fraction. Addition of the fine fraction increased pellet quality (P<0.001).

In chapter 4, thermal inactivation of Salmonella Typhimurium in mash broiler feed was modeled. This study included two studies to investigate kinetic parameters for inactivation of Salmonella Typhimurium in poultry feed heated at various temperatures. In the first study, 2- and 5-gram feed samples, contained in a sample bag, were inoculated with S. Typhimurium and submerged in a water bath heated to 90°C until internal temperatures of 75, 80, and 85°C were reached. In the second study, 2-gram samples were inoculated with S. Typhimurium and submerged into a water bath set at 75, 80, 85, 90, and 95°C heated for 0 to 180s. D-values for linear and Weibull models were calculated for the 5 temperatures. D-values of the linear model were 6.70, 8.83, 12.05, 13.91, and 24.40s, and D-values for the Weibull model were 2.27, 3.67, 3.95, 4.68, and 7.63s when heated to 95, 90, 85, 80, and 75°C. As heating temperature decreased, Double-Weibull and Biphasic models fit all the thermal data, indicating that Salmonella could have generated two subpopulations with different thermo-resistance. Similar to other thermal inactivation models, this study demonstrates that linear, Weibull, Double-Weibull, and Biphasic models could be used to predict thermal inactivation of Salmonella in poultry feed.

Download

Share

COinS