The Effects of Feeding Reduced-oil DDGS to Broilers when Challenged with C. perfringens and Eimeria spp. on Necrotic Enteritis and Intestinal Microbiome.
Type of DegreeMaster's Thesis
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Clostridium perfringens-associated necrotic enteritis (NE) costs the international poultry industry an estimated $6 billion annually. Traditionally, the incidence of NE has been controlled by the use of antibiotic growth promoters (AGPs). However, increased prevalence of NE has been observed alongside the removal of AGPs due to consumer demands. Modification of diets is an alternative method for control, as dietary influences can disrupt the intestinal microbiota composition. Recent implementation of oil-extraction technology by ethanol plants has resulted in reduced-oil DDGS (R-DDGS) sources with varying nutrient content entering poultry diets. Appropriate use of these R-DDGS sources requires information of nutrient utilization and their influence on broiler intestinal microbiome. For these experiments, the objective was to determine the effects of three different R-DDGS sources on broiler performance, intestinal microbiome, and severity and incidence of intestinal lesions after a NE challenge. The four treatments consisted of control (corn-soy) and R-DDGS diets fed across broilers either challenged or unchallenged with Eimeria spp. (d 18) and C. perfringens (d 21 to 23), in a 2 x 2 factorial arrangement of treatments. Treatments were applied to 9 replicate cages of 10 chicks each. Body weight and feed intake were measured over the 28-day feeding period, and body weight gain (BWG) and mortality corrected feed conversion ratio (AFCR) were calculated. Birds were raised in Petersime batteries cages up to 28 d, then euthanized, lesion scored, and jejunum samples collected for analysis by 16S rRNA gene sequencing. A two-way ANOVA was used to determine diet and challenge main effects and interactions (P ≤ 0.05). A Man-Whitney U Test was used to determine pairwise comparisons of treatment microbiome alpha-diversity indices (P ≤ 0.05). Birds consuming the low-oil DDGS (L-DDGS; 4.29% crude fat) diet experienced reduced performance at 14 to 27 d of age (BWG, AFCR) and 0 to 27 d of age (AFCR) (P ≤ 0.05), but challenge had no effect and there was no interaction. When unchallenged, the L-DDGS diet led to a lower Species Richness and Shannon Index value than the control diet (P ≤ 0.05). The medium-oil DDGS (M-DDGS; 6.6% crude fat) diet resulted in greater NE incidence and average lesion score, in which challenge also had an effect (P ≤ 0.05). An interaction effect of diet and challenge was observed on NE severity and NE incidence (P ≤ 0.05). In the third experiment, the M-DDGS diet (7.07% crude fat) led to reduced BWG at 0 to 28 d of age (P ≤ 0.05), but challenge had no effect and there was no interaction. Greater NE incidence and average lesion score was observed in those birds consuming the M-DDGS diet (P ≤ 0.05), with no interaction. When feeding R-DDGS products, amino acid content/quality must be accounted for, as it can result in increased NE incidence and reduced live performance. Future research on the effects of lactate- and butyrate-producing bacteria on NE development could be beneficial, as the industry continues to reduce the use of AGPs.