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The cost of energy-contributing ingredients has increased over the last several years. Defining minimum dietary energy specifications for broilers is a strategy to mitigate high diet cost. Two experiments were conducted to evaluate the effects of diets with graded concentrations of AMEn fed to Hubbard × Cobb 500 (experiment 1) and Ross × Ross 708 (experiment 2) male broiler chicks from 14 to 28 d of age. Both experiments were identical in experimental procedures with the exception of genetic strain. Broilers were fed a common corn-soybean meal-based starter diet from 1 to 13 d of age. At 14 d of age, dietary treatments were provided with 1 of 6 concentrations of AMEn (3,000, 3,030, 3,060, 3,090, 3,120, and 3,150 kcal/kg). In experiment 1, BW gain, feed intake, and FCR of Hubbard × Cobb 500 broilers decreased linearly with increasing AMEn. Linear broken-line response of FCR was estimated at 3,062 kcal of AMEn/kg based on broken-line methodology. In experiment 2, Ross × Ross 708 broilers did not respond to graded concentrations of energy, as indicated by linear and quadratic regression of BW gain, feed intake, caloric conversion, and FCR data. Therefore, Hubbard × Cobb 500 male broilers respond to AMEn from 14 to 28 d of age and may be fed diets formulated at 3,062 kcal of AMEn/kg without loss of performance. Conversely, growth performance of Ross × Ross 708 male broilers was not affected by varying AMEn (3,000 to 3,150 kcal/kg) from 14 to 28 d of age. In addition, the response to AMEn may not be as pronounced with the modern broiler compared with broilers used in previous research.

Inorganic feed phosphates are often incorporated into commercial feed formulations to meet nutritional requirements and enhance feed manufacture; however, peer-reviewed publications supporting the enhancement of manufacture are limited. Two experiments were conducted to determine the effects of inorganic feed phosphates on feed quality and manufacturing efficiency. Feed was manufactured using a Latin square design at the West Virginia University pilot feed mill. In experiment 1, corn- and soybean meal-based diets without meat and bone meal were formulated to include monocalcium phosphate (MCaP) from 2 different manufacturing plants (MCaPA and MCaPB), dicalcium phosphate (DCaP), or tricalcium phosphate (TCaP). In experiment 2, corn- and soybean meal-based diets without meat and bone meal were formulated to include MCaP of a coarse particle size (MCaPC), MCaP, DCaP, or TCaP. Feed production rate was constant among treatments within each experiment owing to the experimental design. The inclusion of TCaP decreased energy consumption of the pellet mill in both experiments. The inorganic feed phosphate source affected pellet durability; however, overall feed quality differences were minimal and would likely not affect bird performance upon feeding.

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.

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.

Meat birds fed high-quality pellets exhibit advantages in rate and efficiency of growth over birds fed poorer quality pellets. However, the associated feed manufacturing cost and reduced production rates to obtain high-quality pellets are viewed by the industry as offsetting the benefits in broiler performance provided by high-quality pellets. With the combination of increased costs for utilities in the feed mill and for feed ingredients, strategies are needed to conserve milling costs while optimizing the efficiency of broiler growth. In this study, we evaluated the effects of feed form on live performance and meat yield of broiler chickens during a 42-d production period. Four treatments were provided from 18 to 42 d of age: 1) high-quality pellets (88% pellet durability index), 2) low-quality pellets (66% pellet durability index), 3) a proportion of the formulated corn added post-pellet (89% pellet durability index), and 4) mash (corn was ground via a roller mill). Broilers fed the high-quality pellets had higher cumulative BW gain and consumed more feed than birds fed low-quality pellets. Mash-fed broilers had poorer growth performance and less meat recovery than birds in the other treatments. Adding corn post-pellet resulted in broilers having similar performance and meat yields compared with those fed high-quality pellets. In this study, we confirm that adding corn post-pellet does not negatively affect growth performance and meat yield. Feeding broilers high-quality pellets provides a benefit in growth rate over feeding low-quality pellets by increasing feed consumption.

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.

Muscle proteins are known to form thermally induced gel networks and may bind particles such as feed constituents. Dietary incorporation of functional proteins may improve pellet quality. Muscle proteins were recovered from rainbow trout by using isoelectric solubilization-precipitation. The objectives of this study were 1) to determine the proximate composition and amino acid content, AMEn, TMEn, and true amino acid digestibility of trout protein isolate and paste (TPP), and 2) to determine the effects of TPP on feed manufacturing, pellet quality, and true amino acid digestibility of broiler diets formulated to include TPP. Four treatments, consisting of 1) a control, 2) 5% TPP (HTPP), 3) 2.5% TPP (LTPP), and 4) 3.9% added moisture (MOIS), were manufactured at the West Virginia University pilot feed mill using a Latin square design. Five percent TPP had the highest pellet quality, followed by LTPP, MOIS, and the control. The improvement in pellet quality could be attributed to gelation of the recovered proteins. Addition of TPP reduced pellet mill production rate. Relative electrical energy usage decreased with MOIS but increased with HTPP relative to the control and LTPP treatments. Negative effects of increased viscosity likely associated with TPP were absent with LTPP. Digestibility of Asp, Glu, Pro, Ile, and Leu were lower for HTPP than the control. However, Ala digestibility was decreased in LTPP compared with the control. Therefore, fish muscle proteins incorporated at less than 5% of the diet may be beneficial to the broiler industry as a pellet binder and nutritive feed additive.

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.