Semester

Fall

Date of Graduation

2013

Document Type

Thesis

Degree Type

MS

College

Eberly College of Arts and Sciences

Department

Animal and Nutritional Sciences

Committtee Chair

Joseph S. Moritz

Committee Co-Chair

Jacek Jaczynski

Committee Member

Janet C. Tou

Abstract

Consumers of pastured hen eggs have justified paying an associated premium price because they perceive animal welfare, sustainability, and nutrition are enhanced compared to conventionally produced eggs. The objective of Study 1 (Chapter 2) was to implement practical management strategies to increase eicosapentaenoic acid (EPA) and docosahexaenoic acid ( DHA) composition of eggs (Experiment 1) and to determine if the same diet formulation would produce an enhanced EPA and DHA egg composition and effect hen health when pasture access and hen breed varied (Experiment 2). For Experiment 1, four dietary treatments were utilized: 1) Basal, 2) Basal + 0.5% Sardine Oil, 3) Basal + 1% Marine Oil, and 4) Basal + 1% Flaxseed Oil. Hens fed Basal + 1% Sardine Oil produced eggs with the greatest concentration of EPA and DHA (approximately 200mg per egg). Aroma and flavor attributes determined by a taste panel did not demonstrate a dislike for pastured or EPA/DHA eggs. Experiment 2 utilized a split-plot design with housing as the whole plot unit (pasture or conventional without pasture) and a factorial arrangement of treatments applied to subplot pens (2 Breed (124 Single-Comb-White Leghorn SCWL or 124 Red Star (RS)) X 2 Diet (1% Sardine Oil ( Sardine) or 1% soybean oil (Basal)). Egg EPA content was affected by a House X Diet interaction, demonstrating that hens fed Sardine had elevated EPA; however, the increase was greater when hens were conventionally housed without pasture. Egg DHA content was affected by Diet, showing increased DHA when hens were fed Sardine compared to Basal. These data show that egg EPA and DHA content can be influenced by both diet and housing system as defined by pasture access. In Study 2 (Chapter 3), barley based diets were fed to Cobb x Cobb 500 broilers. Dietary treatments varied in glucanase doses (125--2000U/kg of feed), glucanase enzyme type (GA and GB), and degree of processing (unprocessed mash and ground pellet). Inclusion of GA decreased gut viscosity (GV) and increased weight gain for ground pelleted diets, but not unprocessed mash diets. For ground pellets, GA dosed at 1000 U/kg of feed was superior to the negative control (150 kcal/kg energy decrease) and indistinguishable from the positive control for ending bird weight and weight gain. These benefits were not observed for GB, perhaps in part due to a 50% decrease in activity post pelleting. Evaluations of glucanase should go beyond in vitro activity and include live bird performance using feed that has undergone pelleting.

Share

COinS