Evaluation of Feed Ingredients and Feed Additives on Poultry Performance and Health

Abstract

The grinding of feed ingredients is a major contributor to the costs of poultry production and there is no optimal ingredient particle size for corn or calcium (Ca). Optimization of ingredient particle size can alleviate costs, improve growth and production, and promote sustainability. Intestinal health is also a key factor of poultry production, but with the limitations of conventional strategies, alternative methods to promote health and performance are necessary. This dissertation investigates corn particle size, alternative feed ingredients (aragonite), and feed additives (direct fed microbials) on their potential to improve turkey and laying hen health and performance. The second chapter is a literature review on ingredient particle size, Ca source, and varying feed additives. The third chapter determined that a smaller corn particle size (581 µm) was necessary for turkeys during the starter 1 phase, but a larger corn particle size (964 µm) is able to maintain performance later on. Turkey poults that consumed the 581 µm corn had an increase in BW (P ≤ 0.01) over the starter 1 phase (0-21d) compared to those consuming the 964 µm corn. By 42 d of age, there were no differences in BW, FI, or FCR indicating that larger corn particle sizes can be used later on to maintain performance and potentially reduce feed costs associated with grinding of ingredients. The fourth chapter evaluated varying Ca sources (blend of 50:50 fine and coarse limestone and fine aragonite) and concentrations (2.46, 3.28, or 4.10%) on laying hen performance, eggshell quality, and bone mineralization. There were minimal differences in performance regardless of Ca source and concentration, however the inclusion of 4.10% limestone resulted in the lowest performance. There was a Ca source main effect for all eggshell quality parameters including increased breaking force, shell thickness, relative shell weight, and specific gravity for birds fed the blend of fine and coarse limestone compared to fine aragonite (P < 0.05). There was a linear increase in bone mineralization for birds fed limestone (P = 0.02) whereas there was no difference for those fed fine aragonite (P = 0.70). These data indicate that fine aragonite was able to maintain production and bone mineralization, but birds fed lower levels of limestone started to pull Ca from the bone to support egg production. Fine aragonite may be used as a higher bioavailable Ca source and less Ca can be added into the diet to reduce costs. A combination of fine and coarse calcium is needed to support eggshell quality. Direct fed microbial (DFM) supplementation (Novela ECL® (ECL), Novela® (NOV), and Amnil® (AMN)) was investigated in the fifth chapter and its effects on laying hen performance, egg quality, and energy metabolism. Supplementation of all DFM altered the energy metabolism within the hen and allowed the birds to partition energy either towards egg production energy and storage. Egg weight was highest in the ECL fed birds followed by AMN then NOV and the control (P ≤ 0.01). An increase in egg weight resulted in a higher egg mass for ECL and AMN (P ≤ 0.01) which improved the feed conversion ratio by 7 and 9 points, respectively (P ≤ 0.01). Inclusion of NOV increased the body weight and stored energy within the hen (P = 0.05) whereas ECL and AMN diverted energy down a productive pathway and improved productive performance. Inclusion of both NOV and AMN increased egg breaking force compared to other treatments (P ≤ 0.01). The sixth chapter investigated the effects of a larger corn particle size on feed milling efficiency and the amelioration of a coccidial challenge in turkey poults using performance, intestinal permeability, nutrient digestibility, and litter moisture. The coarse corn (1,049 µm) had a higher mill load than the fine corn (597 µm; P < 0.01) but pellet quality was not different (P > 0.05). No interactions occurred for any of the measured parameters between corn particle size and coccidiosis challenge from 21 to 42 d. Inclusion of the coarse corn reduced FI and BW (P ≤ 0.01). Coccidiosis reduced all performance parameters and apparent ileal crude fat digestibility compared to the non-challenged birds (P ≤ 0.01). Litter moisture increased on D35 (d 7 post coccidiosis vaccination) for challenged birds (P = 0.02). A coccidiosis challenge reduced performance in turkey poults from 21 to 42 d and large particle corn was not able to overcome the coccidia challenge. This dissertation conveys possible ways to maximize turkey and laying hen production parameters through feed additives and optimization of ingredient particle size. These experiments provide insight on potential strategies to lower feed costs and varying feed additives to improve or maintain turkey and laying hen production and performance.