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Feed ingredient price has influenced nutritionists to improve diet nutrient availability through the use of exogenous enzyme cocktails (EEC). If EEC are to be added at the mixer before pelleting, then pelleting variables that increase the heat and pressure of feed may denature EEC components, decreasing EEC efficacy. Three experiments were conducted to assess the efficacy of a commercially available EEC postpelleting. The primary pelleting variable manipulated was steam conditioning temperature (71 to 93°C). However, additional variables were modified in subsequent experiments to lessen the potential for high heat and pressure effects on the feed. Dietary treatments consisted of a positive control, a negative control that was reduced in ME and available phosphorus, and a negative control + EEC. Experiment 1 used conditioning temperatures of 82, 88, and 93°C. This experiment indicated no benefit from the EEC on 4- to 21-d broiler chick performance. Experiment 2 used increased mixer-added fat and similar conditioning temperatures relative to experiment 1. Again, no benefit from the EEC was demonstrated on 4- to 21-d chick performance. Experiment 3 used similar diet formulations as experiment 2, a thinner pellet die, conditioning temperatures of 71, 77, and 82°C, and the inclusion of an unconditioned mash treatment. Benefits from the EEC were demonstrated for BW gain and FCR for the unconditioned mash treatment. Trends (P = 0.07) for improved FCR were observed for the EEC pelleted at 82°C. Performance observations in experiment 3 were supported by AMEn data. Overall, on the basis of these studies, future evaluations of EEC efficacy postpelleting should consider several manufacturing variables.

Most commercial broilers are fed pelleted diets containing an exogenous phytase. Various techniques exist to prevent denaturation of phytase during pelleting, but the potential remains for phytase to lose efficacy in liberating phytate-bound phosphorus. Dietary treatments consisted of positive control and negative control diets differing in nonphytate phosphorus by 0.13%, as well as the negative control diets containing 1 of 9 Escherichia coli-derived mixer-added heat-stable phytases. Diets were steam conditioned at 71°C (160°F), 77°C (170°F), and 82°C (180°F) before pelleting. Feed samples were analyzed for phytase pre- and postpelleting by a commercial laboratory to determine retained activity. Pellets conditioned at 77°C were chosen for further evaluation via a feeding experiment because all 9 enzymes demonstrated high retained activity in vitro (=60%). Diets were fed to Cobb 500 male broilers from 3 to 21 d. Feed intake, FCR, BW gain, tibia breaking strength, and tibia bone ash weight per chick were calculated. Seven out of 9 enzymes resulted in BW gain similar to that of the positive control diet. Five of those enzymes resulted in decreased FCR by an average of 8 points compared with the other 2. Tibia measures demonstrated additional differences among enzyme treatments. Phytase activity did not positively correlate with performance or bone mineralization measures. Therefore, evaluations of phytase may need to include in vivo bird testing beyond in vitro activity assays to fully assess efficacy. It is important to note that our conclusions in this study were derived using specific phytase products that were analyzed for activity by using specific protocols, and diets were pelleted within a selected range of processing conditions (i.e., 77°C and 10 s of conditioning); using alternative methodologies may result in different conclusions.

Phytogenic feed additives (PFA) are purported to possess antimicrobial properties as well as nutrient-sparing characteristics that may aid in alleviating high diet costs. However, for PFA to assist nutritionists, matrix values must be determined and implemented in practical diet formulation. In experiment 1, we used broiler performance measures to evaluate proposed matrix values (PMV) for a commercially available PFA, and we assessed nutrient sparing when the product was combined with a commercial phytase, carbohydrase, and protease that can be described as an exogenous enzyme blend (EEB). In experiment 2, we determined the TMEn and true amino acid digestibility (TAAD) of the diets used in experiment 1. Main effects and interactions of PFA, PMV, and EEB were determined. Decreasing the basal diet by the PMV of the PFA decreased broiler BW gain and increased FCR. Including PFA in this diet restored BW gain and FCR. The PFA was not additive or synergistic with EEB. Incorporating PFA with PMV and EEB tended to decrease the TMEn and tested the TAAD. Decreased 4- to 21-d broiler BW gain, TMEn, and TAAD associated with using PFA with PMV and EEB may be associated with several mechanisms regarding plane of nutrition, gut microflora, substrate competition, or their combination.

The proposed health benefits, product freshness, and concern about antibiotic-resistant bacteria have bolstered sales of organic poultry products. However, outdoor requirements for organic poultry could increase exposure to bacteria, including Salmonella. The objective of this study was to assess the effects of prebiotics and probiotics in feed (experiment 1) and acidifying water treatments (experiment 2) on organic broiler performance and the presence of preslaughter Salmonella. In experiment 1, a prebiotic (MOS), 2 probiotics, and a control treatment were implemented. In experiment 2, raw apple cider vinegar, an organic acid blend, H2O2, and a control treatment were incorporated into the watering systems. For both experiments, 300 one-day-old Cobb 500 male chicks were randomly assigned to treatment and pen. On d 21, birds were weighed and allocated at 13 per pen within each of the 5 housing locations providing pasture access at the West Virginia University Certified Organic Farm. Data collection occurred from d 21 to 49. On d 21, probiotic 1, the prebiotic, and the organic acid blend yielded the highest BW but demonstrated the same ending bird BW. However, birds provided probiotic 1 and the prebiotic were at least 86 and 72% less likely to be contaminated with Salmonella preslaughter. The lowest bird BW were achieved by birds provided H2O2 throughout the study; however, these birds were at least 7% less likely to harbor Salmonella preslaughter compared with birds in the control treatment.

Pelleted feed increases BW gain and FE in broilers when compared with mash feed. However, the improvement in broiler performance may rely on pellet quality. At the West Virginia University pilot feed mill and broiler housing facilities, 2 experiments were conducted. In experiment 1, pellets were produced through varying pelleting techniques to create 5 diets unique in feed form. These diets were fed to male Cobb 500 broilers for performance evaluation. The expected broiler performance was not observed, perhaps because the nutrient availability of the diets was affected by altering the pelleting technique. Experiment 2 was designed to explain variations in feed form on broilers of varying sex categories, with consistent nutrient availability among treatments. Treatments consisted of the following pellet-to-fine ratios: 90:10 (high pellet quality), 60:40 (medium pellet quality), 30:70 (low pellet quality), and 0:100 (ground pellets). Males had improved feed conversion and were larger than females, and those in the group with an equal male:female ratio were intermediate. Whole pellets in the diet improved FCR compared with ground pellets. Broilers fed high-quality pellets exhibited the greatest carcass weight. An economic model based on intake, 2 scenarios of feed costs, and carcass weight was created using the data obtained from experiment 2.

The prices of fat and diet formulations with exogenous enzymes have caused a reduction in the amount of fat added to broiler diets. Although diets may be cheaper to produce, there is potential for nutrient and exogenous enzyme destruction with low inclusions of fat (0.5 to 1%) because of frictional heat and shear forces produced in the pellet die. Additionally, much of the added fat may be applied by using postpellet spray application, and the amount of fat added in the mixer may become negligible. Thermal inactivation of exogenous enzymes and the occurrence of unfavorable reactions (e.g., Maillard reaction, protein cross-linking) may be abated by increased levels of fat included at the mixer before pelleting [i.e., mixer-added fat (MAF)]. In this study, we evaluated the effects of MAF (1, 2.5, or 4%) with or without the addition exogenous enzymes (carbohydrase, protease, and phytase), and at different conditioning temperatures (82 or 85°C), on finisher phase feed manufacture, broiler performance variables, and processing yields. Increasing MAF reduced the electrical energy usage required to manufacture broiler feed (P < 0.02). Feed intake during the grower and finisher phases and live weight gain during the finisher phase were increased with enzyme addition (P < 0.001). Enzyme addition, conditioning temperature and MAF interacted in their effects on FCR from 23 to 38 d of age (P = 0.009). Overall, enzyme addition decreased FCR, but the effect was greatest with 1% MAF and 82°C or 4% MAF and 85°C. Increasing the MAF and conditioning temperature reduced abdominal fat pad yield (P < 0.03). No difference in breast or leg yield was due to any of the factors (P > 0.05). It is likely that increased MAF improved exogenous enzyme retention and nutrient utilization by broilers. Subject to current fat prices, increasing MAF may reduce the total cost of broiler production, particularly when the reduction of electrical energy usage is considered.

Least-cost diet formulations and pellet mill operating techniques vary widely. As a result, pellet quality is often inconsistent. Past research has associated pellet quality changes with feed formulation and manufacturing techniques. However, the interaction between the 2 factors has rarely been explored. The objective of the current study was to evaluate the effects of altering a least-cost diet (LC) formulation and altering manufacturing techniques on pellet processing variables and quality. Generally, pellet quality improves with higher levels of protein and moisture. Therefore, increased levels of CP and moisture were added to LC broiler starter and grower formulations to compose a research-based (RB) formulation. The LC and RB formulations were pelleted using 2 manufacturing techniques, a thin die with a fast production rate (TF) or a thick die with a slow production rate (TS). During manufacture of the starter diets, the RB formulation improved the pellet durability index (PDI) and modified PDI (MPDI) while decreasing pellet mill relative electrical energy usage (P = 0.05) compared with the LC formulation. The TS technique increased PDI and MPDI while decreasing production of fines (P = 0.05) compared with the TF technique. During manufacture of the grower diets, the RB formulation and TS technique resulted in decreased production of fines (P = 0.05) compared with the LC formulation and TF technique. A significant interaction observed for PDI and MPDI of the grower diets indicated that the RB formulation improved pellet quality and would be even more beneficial if a mill used a TF technique (P = 0.05). We conclude that diet formulation and manufacturing technique are, in fact, linked and must be considered when attempting to optimize pellet quality.

Optimizing the diet formulation and manufacturing technique improves pellet quality. However, high pellet quality must equate to improved broiler performance to justify the increased cost output. The objective of the current study was 2-fold: 1) to assess broiler performance based on changes in pellet quality obtained by altering the diet formulation and manufacturing technique, and 2) to assess broiler performance when using pelleted diets including and excluding antibiotics. Experimental treatments were arranged in a 2 × 2 × 2 factorial design consisting of 2 diet formulations (least cost or research based), 2 manufacturing techniques (thin die with a fast production rate or thick die with a slow production rate), and 2 antibiotic inclusions (including antibiotics or excluding antibiotics). Starter diets were fed in crumbled form and grower diets were fed in pelleted form. Antibiotic inclusion had no effect on broiler performance. Feeding the research-based formulation improved live weight gain and decreased fat pad yield compared with feeding the least-cost formulation. Moreover, the research-based formulation was found to be most beneficial for carcass and breast yield when the thin die plus fast production rate technique was used. In conclusion, to maximize broiler performance, the diet formulation and manufacturing technique must be considered.

In response to the impending ban on synthetic methionine in organic poultry diets, researchers have focused on finding alternative strategies to supply this amino acid. The objectives of this study were to assess performance and carcass characteristics of broilers fed diets devoid of synthetic methionine by using 1) a slow-growing and a fast-growing genotype, 2) choice-feeding management (supplying grain and a complementary premix in 2 separate feeders), and 3) pasture access and seasonal variation. Inclusion of fish meal and high percentages of soybean meal enabled the specific genotype methionine requirement to be met. All diets were certified organic. The experiment was conducted during the grower and finisher phases in 4 different seasons: late fall, spring, summer, and early fall. Pasture access was assessed either by housing broilers on the West Virginia University Organic farm and giving them outdoor access, or by housing broilers on the West Virginia University Animal Sciences farm and giving them no outdoor access. Fast-growing genotypes were superior in performance and carcass characteristics compared with slow-growing genotypes, and choice-feeding management did not improve performance or carcass characteristics. Pasture access tended to have no effect on slow-growing broilers and decreased the performance of fast-growing broilers. Performance was decreased in late fall, likely because of cold ambient temperatures.