Metabolizable energy of corn, soybean meal and wheat for laying hens

Metabolizable and net energy evaluation of corn, soybean meal, and wheat bran in growing male pheasants

The apparent metabolizable energy(AME), AME corrected to zero-nitrogen retention(AMEn) and net energy (NE) values of corn, soybean meal and wheat bran were determined in growing male pheasants with reference diet substitution method. Reference diet was formulated according to standard Pheasants requirement, and test diets contained 40 % of corn, 20 % of soybean meal and 30 % of the wheat bran samples of thereference diet. Ninety male pheasants at the age of 12 wk with similar body weights were randomly divided into four groups. The heat production and energy metabolism of birds were measured in open-circuit respiratory chambers with 6 replicates (4 birds per replicate) per diet in a randomized design. Birds were fed experimental diets for 6 D in the chamber as adaptation. During the following 3 D, feed intake, metabolizable energy value, nitrogen balance, energy balance, O2 consumption, CO2 production, and energy efficiency were determined. Pheasants were allowed free access to feed under controlled environmental conditions. Feces were collected using respiratory calorimetry. The AME values of corn, soybean meal and wheat bran were 14.62 MJ/kg, 10.62 MJ/kg and 7.57 MJ/kg DM, respectively. The corresponding AMEn values were 14.71 MJ/kg, 10.64 MJ/kg and 7.25 MJ/kg DM, respectively. The NE values were 11.20 MJ/kg, 7.02 MJ/kg, and 6.19 MJ/kg DM, respectively. The NE:AME ratios of corn, soybean meal and wheat bran were 77.61 %, 65.68 % and 85.17 %, respectively. The NE:AMEn ratios of corn, soybean meal and wheat bran were77.22 % and 66.89 % and 84.76 %, respectively. The AME, AMEn and NE values of corn were higher than the other two samples.

Prediction equations of the metabolizable energy in corn developed by chemical composition and enzymatic hydrolysate gross energy for roosters

Two experiments were conducted to establish the prediction equations for AME and TME of corn based on chemical composition and enzymatic hydrolysate gross energy (EHGE) in roosters. In experiment 1, eighty 32-wk-old Hy-line Brown roosters with an average body weight of 2.55 ± 0.21 kg were randomly assigned to 10 diet treatments in a completely randomized design to determine AME and TME by the force-feeding method. Each treatment had 8 replicates with 1 bird per replicate. The 10 test diets used in the experiment were formulated with corn (including 96.10%) as the sole source of energy. In experiment 2, the EHGE of 14 corn samples was measured by the computer-controlled simulated digestion system (CCSDS) with 5 replicates of each sample. The average AME and TME values of corn were 14.58 and 16.46 MJ/kg DM, respectively. The EHGE of 14 corn samples ranged from 14.66 to 15.89 (the mean was 15.24) MJ/kg DM. The best-fit equations for corn based on chemical composition were AME (MJ/kg DM) = 14.5504 + 0.1166 × ether extract (EE) + 0.5058 × Ash - 0.0957 × neutral detergent fiber (NDF) (R2 = 0.8194, residual standard deviation (RSD) = 0.0860, P < 0.01) and TME (MJ/kg DM) = 16.0625 + 0.1314 × EE + 0.4725 × Ash - 0.0872 × NDF (R2 = 0.7867, RSD = 0.0860, P < 0.01). The best-fit equations for corn based on EHGE were AME (MJ/kg DM) = 7.8883 + 0.4568 × EHGE (R2 = 0.8587, RSD = 0.0693, P < 0.01) and TME (MJ/kg DM) = 10.0099 + 0.4228 × EHGE (R2 = 0.8720, RSD = 0.0608, P < 0.01). The differences between determined and predicted values from equations established based on EHGE were lower than those observed from chemical composition equations. These results indicated that EHGE measured with CCSDS could predict the AME and TME of corn for roosters with high accuracy.

Nutritional, Productive, and Qualitative Characteristics of European Quails Fed with Diets Containing Lipid Sources of Plant and Animal Origin

The objective of this study was to investigate the impact of alternative lipid sources on nutrient metabolism, performance, carcass characteristics, and meat quality in European quails. Trial 1 determined the energy values and nutrient metabolizability of non-conventional lipid sources. Six treatments (control, soybean oil, conventional corn oil, distilled corn oil, poultry fat, and beef tallow) were randomly assigned with 10 replicates per treatment. Trial 2 evaluated animal performance, carcass characteristics, and meat quality using a randomized design with five treatments and 10 replicates each. Statistical analysis showed no significant difference in apparent metabolizable energy corrected by nitrogen (AMEn) and coefficients of metabolizability (CM%) among the lipid sources. The AMEn values found were 8554 for soybean oil, 7701 for corn, 7937 for distilled corn oil, 7906 for poultry fat, and 7776 for beef tallow (kcal/kg). The CM values were 88.01% for soybean oil, 79.01% for corn oil, 84.10% for distilled corn oil, 81.43% for poultry fat, and 79.28% for beef tallow. The inclusion of lipid sources of plant and animal origin in the diet of 7-35-day old meat quails did not influence performance or carcass and cut characteristics. The inclusion of distilled corn oil increased carcass yield and influenced skin and meat color parameters. AMEn values varied for each lipid source. The inclusion of distilled corn oil positively influenced skin and meat color as well as carcass yield in quails.

Apparent Metabolizable Energy and Amino Acid Digestibility of Corn of Different Origin Fed to Male Broilers from 12 to 18 Days of Age

Apparent metabolizable energy (AME) and apparent ileal amino acid digestibility (AIAAD) of corn samples from the United States (USA), Argentina (ARG), and Brazil (BRA) fed to 432 and 324 YPM × Ross 708 male broilers from 12 to 18 d of age were evaluated using the total collection method (experiment 1) and index method (experiment 2), respectively. In experiment 1, broilers were fed either a basal diet with 30% dextrose inclusion, or a test diet obtained by the replacement of dextrose with corn from each origin. In experiment 2, broilers were fed one of three test diets in which corn from each origin was the only source of AA. All dietary treatments had 12 replicate cages. Similar (p > 0.05) AME (dry-matter basis) values were observed between corn samples. The highest gap in AME (43 kcal/kg) was found between corn from BRA (3694 kcal/kg) and corn from the USA (3651 kcal/kg). Likewise, similar (p > 0.05) AIAAD values were observed for all AA apart from tryptophan (Trp), as corn from BRA (77.45%) had a higher (p = 0.024) Trp digestibility than corn from the USA (72.53%). Overall, a similar nutrient utilization by the birds was observed for the corn samples, regardless of origin.

Effect of Corn Grinding Methods and Particle Size on the Nutrient Digestibility of Chahua Chickens

This study investigates the effect of grinding methods, including roller mill, hammer mill, and two-stage grinding, on the particle size distribution of corn and the effect of corn particle size on the nutrient digestibility of native chickens in Southwest China. The roller mill, hammer mill, and a combination of the hammer mill and roller mill were used to obtain corn with various coarseness. Corn with different coarseness obtained using a combination of the hammer mill and roller mill was fed to Chahua chicken No. 2-type chickens (CHC2s). A total of 192 CHC2s in weeks 12 and 19 were randomly allocated to eight groups in triplicate. The results show that the geometric mean diameter (d_gw) and the geometric standard deviation (S_gw) were significantly (p < 0.05) affected by the grinding methods. The S_gw obtained when using a sieve of 2.0 mm in a hammer mill was lower (p < 0.05) than that obtained using a 4.5 mm sieve. Combining the roller mill and hammer mill increased the uniformity of the particle size when grinding coarse particles. For fine particles, the d_gw and S_gw obtained when using the hammer mill were significantly lower (p < 0.05) than those obtained when using the roller mill and two-stage grinding method. Reducing the particle size of the corn (<900 µm) significantly increased the dry matter, crude protein, amino acid digestibility, and apparent metabolizable energy in the chicken in weeks 12 and 19. Fine particles significantly increased the crude protein digestibility of the CHC2s at week 12, while there was no significant effect on the crude protein and amino acid digestibility in the CHC2s at week 19. In conclusion, different grinding methods can affect the particle size distribution. For a coarse particle size, combining the roller mill and hammer mill tends to produce a more uniform particle size. Finely ground corn (between 700 µm and 900 µm) improved the dry matter (DM), apparent metabolizable energy (AME), and crude protein (CP) digestibility of the CHC2s at week 12. An increased particle size did not impact the CP and amino acid (AA) digestibility of the CHC2s at week 19.

Compound non-starch polysaccharide enzymes improve growth performance, slaughter performance, immune function, and apparent utilization rate of nutrients in broiler chickens fed a low-metabolizable energy diet

This study aimed to investigate the effects of compound non-starch polysaccharide (NSP) enzymes on growth performance, slaughter performance, immune function, and apparent utilization of nutrients in broiler chickens fed a low-metabolizable energy diet. A total of 240 healthy 1-day-old AA broilers (Arbor Acres, 47.2 ± 0.31 g) were randomly divided into four treatment groups, each with six replicate groups and 10 broilers per replicate. The control group was fed a basal diet; the EL-H group was fed the basal diet supplemented with 200 mg/kg compound NSP enzyme, including β-mannanase 5,000 IU/g, β-glucanase 2000 IU/g, xylanase 10,000 IU/g, and cellulase 500 IU/g. The EL-M group was fed the basal diet with 50 kcal/kg metabolizable energy removed, supplemented with 200 mg/kg compound NSP enzyme. Finally, the EL-L group was fed the basal diet with 100 kcal/kg metabolizable energy removed, supplemented with 200 mg/kg compound NSP enzyme. The results showed that feeding with a low-metabolizable energy diet supplemented with compound NSP enzymes did not significantly affect the growth performance of broilers (p > 0.05). Compared with the control group, the abdominal fat rate of broilers in the EL-L group was significantly reduced, and that of broilers in the EL-M group was significantly increased (p < 0.05). Apparent utilization of dry matter, crude protein, and energy in the diet was lower in the control group than in the EL-L group, but significantly higher in the control group than in the EL-H group (p < 0.05). In addition, apparent utilization of crude fiber was significantly increased in the EL-H, EL-M, and EL-L groups compared with the control group (p < 0.05). In conclusion, this experiment showed that the addition of 200 mg/kg compound NSP enzyme enabled maintenance of the normal growth and development of broiler chickens fed a low-metabolizable energy diet (replacing 50-100 kcal/kg metabolizable energy). This study provides a theoretical basis for the application of the compound NSP enzyme in broiler chickens.

Oil Extracted Moringa peregrina Seed Cake as a Feed Ingredient in Poultry: A Chemical Composition and Nutritional Value Study

The chemical composition, antioxidant activity, tannic acid content, mineral, fatty acid, and amino acid profiles of oil-extracted Moringa peregrina seed meal (OEMPSM) were determined. Apparent (AME) and true (AMEn) metabolizable energy and apparent (AAAU) and true (TAAU) amino acid utilization were evaluated using a precision feeding trial. The protein (CP) quality was evaluated by a total efficiency analysis method. The antioxidant activity, gauged by 2,2-diphenyl-1-picrylhydrazyl (DPPH), was 237, 353, and 15.2 mg/mL for the water and ethanol extracts, and ascorbic acid, respectively. Tannic acids were 131.4 mg/100 g dry weight. The OEMPSM had 27.2% CP and 22.4, 15.1, and 15.8 MJ/kg of gross energy, AME and AMEn, respectively. The neutral detergent fiber, acid detergent fiber, and hemicellulose were 40.2, 29.7, and 10.5% DM, respectively. The 15.41% of total fatty acids were saturated and 84.57% unsaturated. The AAAU and TAAU of OEMPSM were 30.92% and 61.06%, respectively. From findings, OEMPSM comprises a valuable level of bioactive substances, amino acids, fatty acids, minerals, and energy; it can provide up to 1.12% of the requirements of total amino acids of chickens (1-21 days); however, the quality of its protein was found to be 44.6% less than that of protein of soybean meal.

Comparative study of apparent metabolizable energy and net energy values of dephenolized cottonseed proteins for laying hens

Optimizing the energy utilization of nutrients and ensuring maximum benefits are continuous goals for livestock producers. The net energy (NE) value of feed reflects its nutritional value in the precision feeding system. An experiment was conducted to determine the apparent metabolizable energy (AME) and NE values of 3 types of dephenolized cottonseed protein (DCP) for Hy Line Brown hens aged 42 to 45 weeks using the reference diet substitution method. A reference diet based on corn soybean meal was used to meet the nutritional needs of Hy Line Brown laying hens. To render the crude protein and energy values of the 3 test diets similar, 10.5%, 12%, and 16% of the gross energy yielding ingredients from the reference diet were replaced with DCP 1, DCP 2, and DCP 3, respectively. The birds were fed 4 diets during a 7-d adaptation period. After the dietary adaptation period, 2 birds per replicate from each treatment group were placed in an individual open circuit respiratory calorimetry chamber for a 3-d experimental period. Daily O₂ consumption and CO₂ production were recorded, and excreta samples were collected. The AME values of DCP 1, DCP 2, and DCP 3 were 3,049.05, 2,820.13, and 2,982.31 kcal/kg of dry matter (DM), respectively. The NE values of DCP 1, DCP 2, DCP 3 were 1,475.77, 1,910.31, and 1,905.37 kcal/kg of DM, respectively, and the NE:AME ratios were 48.40%, 67.74%, and 63.89%, respectively. Our data show that the AME value of DCP does not reflect the nutritional value of the feed. The NE value of DCP with a high ME value was not necessarily high.

Characterization of a New Xylanase Found in the Rumen Metagenome and Its Effects on the Hydrolysis of Wheat

Wheat is the main ingredient of poultry diet, but its xylan has an adverse impact on poultry production. A novel xylanase from beef cattle rumen metagenome (RuXyn) and its effect on the wheat hydrolysis were investigated in the present study. The RuXyn coded for 377 amino acids and exhibited low identity (<40%) to previously reported proteins. The RuXyn was heterologously expressed in Escherichia coli and showed maximum activity at pH 6.0 and 40 °C. The activity of RuXyn could be increased by 79.8 and 36.0% in the presence of Ca²⁺ and Tween 20, respectively. The soluble xylan and insoluble xylan in wheat could be effectively degraded by RuXyn and xylooligosaccharides produced accounting for more than 80% of the products. This study demonstrates that RuXyn has substantial potential to improve the application of wheat in poultry production by degrading wheat xylan and the accompanying xylooligosaccharides produced.

Methodologies for energy evaluation of pig and poultry feeds: A review

The cost of feed represents an important part of the total cost in swine and poultry production (>60%) with energy accounting for at least 70% of feed cost. The energy value of ingredients or compound feeds can be estimated as digestible (DE), metabolisable (ME) and net energy (NE) in pigs and ME and NE in poultry. The current paper reviews the different methods for evaluating DE, ME and NE of feeds for monogastric animals and their difficulties and limits, with a focus on NE. In pigs and poultry, energy digestibility depends on the chemical characteristics of the feed, but also on technology (pelleting, for instance) and animal factors such as their health and body weight. The ME value includes the energy losses in urine that are directly dependent on the proportion of dietary N excreted in urine resulting in the concept of ME adjusted for a zero N balance (MEn) in poultry. For poultry, the concept of true ME (TME, TMEn), which excludes the endogenous fecal and urinary energy losses from the excreta energy, was also developed. The measurement of dietary NE is more complex, and NE values of a given feed depend on the animal and environmental factors and also measurement and calculation methods. The combination of NE values of diets obtained under standardised conditions allows calculating NE prediction equations that are applicable to both ingredients and compound feeds. The abundance of energy concepts, especially for poultry, and the numerous feed and animal factors of variation related to energy digestibility or ME utilisation for NE suggest that attention must be paid to the experimental conditions for evaluating DE, ME or NE content. This also suggests the necessity of standardisations, one of them being, as implemented in pigs, an adjustment of ME values in poultry for an N retention representative of modern production conditions (MEs). In conclusion, this review illustrates that, in addition to numerous technical difficulties for evaluating energy in pigs and poultry, the absolute energy values depend on feed and animal factors, the environment, and the methods and concepts. Finally, as implemented in pigs, the use of NE values should be the objective of a more reliable energy system for poultry feeds.

Determination of metabolizable energy and amino acid digestibility in various hatchery byproducts for broiler chickens

The objective of the present experiment was to determine ME concentrations and amino acid (AA) digestibility in various hatchery byproducts (HBPs) for broiler chickens. In experiment 1, a total of forty 60-day-old female broiler chickens were allotted to 1 of 5 dietary treatments with 8 replicates and used to measure ME concentrations in HBPs. The basal diet was prepared to contain corn, soybean meal, corn oil, and other non-energy ingredients. Additional 4 experimental diets were prepared to contain 10% of infertile eggs (IFE), unhatched eggs (UHE), low-grade or dead chicks (LDC), and mixture (MIX; 55% IFE, 10% UHE, 10% LDC, and 25% hatched eggshells). In experiment 2, a total of seven hundred and sixteen 1-day-old mixed-sex broiler chickens (1:1 ratio of males and females) were allotted to 1 of 5 dietary treatments with 7 replicates per treatment and used to determine apparent ileal digestibility (AID) and standardized ileal digestibility (SID) of AA in HBPs. The experimental diets consisted of a nitrogen-free diet and 4 diets containing IFE, UHE, LDC, or MIX as a sole source of AA. Results indicated that AME and AME_n values were greater (P < 0.05) for LDC than for IFE, which had greater (P < 0.05) AME and AME_n values for UHE and MIX. The AID and SID of most AA in LDC were greater (P < 0.05) than those in MIX, whereas IFE and UHE had intermediate AID and SID of those AA as compared to LDC and MIX. Average SID of essential AA in LDC was greater (P < 0.05) than in UHE and MIX, but the average SID of nonessential AA did not differ among 4 HBPs. In conclusion, LDC has the greatest ME concentrations and AA digestibility among 3 individual HBPs (IFE, UHE, and LDC). The mixture of HBPs has the least ME concentrations and AA digestibility in broiler chickens. The ME and AA digestibility of HBPs are likely affected by inclusion amounts of hatched eggshells. However, high concentrations of ME and available AA demonstrate that individual HBPs and their mixture are potential protein ingredients for broiler diets.

Impact of combined α-galactosidase and xylanase enzymes on growth performance, nutrients digestibility, chyme viscosity, and enzymes activity of broilers fed corn-soybean diets

Two experiments were conducted to investigate the effects of a combined α-galactosidase and xylanase preparation on nutrients digestibility and growth performance in broiler chickens. Experiment 1 had 240 broilers allocated to 3 treatments with the dietary supplementation of 0, 300, and 500 g/t of the enzyme combination. Diet and amino acid (AA) digestibility were assessed. Experiment 2 was a 2 × 3 (enzyme × diet) factorial arrangement with 10 replicates of 12 male broilers per replicate. Diets were based on corn-soybean meal (SBM) diet and had 3 nutritional levels (normal, 2% apparent metabolizable energy (AME) and crude protein (CP) reduction, and 4% AME and CP reduction). Each of these diets was fed with or without enzyme supplementation. Growth performance, chyme viscosity, nutrients digestibility, and endogenous enzymes activity were assessed. In experiment 1, enzyme supplementation improved the digestibility of Ca (P = 0.025) and ileal digestibility of total AA, Pro, Alu, Ile, Lys, His, Thr, Glu, Val, Leu, Tyr, and Phe (P < 0.05), and also tended to increase the AME of diets (P < 0.10). In experiment 2, broilers fed the corn-SBM diet with 4% nutrient reduction had better growth performance (P < 0.05), jejunal digesta viscosity at 42 d (P < 0.01), and lower digestibility of gross energy (GE; P < 0.05) when compared with those fed the normal nutrient diet. Enzyme inclusion increased digestibility of CP (P = 0.044), GE (P = 0.009), raffinose (P < 0.001) and stachyose (P < 0.001), improved average daily gain (P = 0.031), and reduced jejunal digesta viscosity at 42 d (P = 0.011). Besides, similar improvements trend in amylase, trypsin, sucrase, and maltase activity with enzyme inclusion were observed as with energy. These data support that the enzyme supplementation increased nutrients and ileal AA digestibility, improved performance and endogenous enzymes activity.

Effect of Biscuit Flour and Fermented Defatted "Alperujo" Co-Administration on Intestinal Mucosa Morphology and Productive Performance in Laying Hens

Simple Summary

Spanish production of compound feed is among the most important in the Member States of the European Union for all livestock species. However, due to the environmental impact of this large-scale production system, it is important to focus on sustainability, promoting initiatives such as the use of by-products from the food industry applied to animal feed. In this study, laying hens received two types of dietary supplement: biscuit meal, which is a co-product of the human food industry commonly used in the manufacture of compound feed, obtained from the recycling of wasted or expired food products; and fermented defatted “alperujo”, a by-product of modified olive oil, which contain numerous substances with beneficial properties for intestinal health. Hens co-administered with these supplements showed increased intestinal villi development, resulting in improved health. In conclusion, these by-products can contribute to the prevention of intestinal diseases, as well as to the reduction of environmental pollution.

Abstract

In this study, the effects of co-administration with biscuit flour and fermented defatted “alperujo” (FDA) on gut health were evaluated in a batch of laying hens (Hy-Line 2015) on a commercial farm. Animals were divided into two groups: control group and treatment group; and histological and morphometric analyses of all sections of the intestine (duodenum, jejunum, ileum, cecum and rectum) were performed at 10, 18, 25, 50 and 75 weeks of age. During the whole productive period, a decrease in the mortality rate (p = 0.01) was observed in treated hens, as well as an increase in the number of eggs produced (p < 0.001), their size (p < 0.025), and weight (p < 0.024). In the early and late stages of production (10, 18 and 50 weeks), a significant increase (p < 0.001) in the height and depth of the intestinal villi was observed in the treatment group. Villi height was also significantly higher (p < 0.001) in the treatment group up to week 50 in the cecum, and at weeks 18 and 50 in the rectum. We concluded that an economical and sustainable feeding system with less environmental impact, such as co-supplementation with biscuit flour and FDA, could maintain gut health without negatively impacting laying hens’ productive performance.

The Potential of Locally-Sourced European Protein Sources for Organic Monogastric Production: A Review of Forage Crop Extracts, Seaweed, Starfish, Mussel, and Insects

Organic monogastric agriculture is challenged because of a limited availability of regional and organic protein-rich ingredients to fulfill the amino acid requirements. The development of novel feed ingredients is therefore essential. The use of starfish (Asterias rubens), mussel (Mytilus edilus), insect, green and brown seaweed, and forage crop extracts exhibits different approaches to increase protein availability in a sustainable manner through improving the protein quality of existing ingredients, better use of under- or unutilized material, or development of circular bioeconomy. This review assessed limitations and opportunities of producing, processing, and using these novel ingredients in feed. The use of non-renewable resources and the effect on the environment of production and processing the feed ingredients are described. Protein concentration and amino acid quality of the feed ingredients are evaluated to understand their substitution potential compared with protein-rich soya bean and fishmeal. Feedstuffs’ effect on digestibility and animal performance is summarized. With the exception of seaweed, all novel ingredients show potential to partly substitute fishmeal or soya bean fulfilling part of the protein requirement in organic monogastric production. However, improvements during production and processing can be made to enhance protein quality, sustainability of the novel ingredients, and nutrient utilization of novel feed ingredients.

A New Approach for the Production of Selenium-Enriched and Probiotic Yeast Biomass from Agro-Industrial by-Products in a Stirred-Tank Bioreactor

The production of biomolecules using agro-industrial by-products as feedstock is a growing trend worldwide. Selenium (Se) is a trace element essential for health, and the Se-enrichment of yeast biomass can enhance its benefits. This study investigated the feasibility of the production of Saccharomyces cerevisiae Se-enriched biomass using a medium composed of corn bran and soybean bran acid hydrolysates as carbon and nitrogen sources in a stirred-tank reactor. After hydrolysis, hydrolysates presented complex composition and high concentrations of sugars, proteins, and minerals. The use of a stirred-tank bioreactor leads to the production of 9 g/L S. cerevisiae biomass enriched with 236.93 μg/g Se, and 99% cell viability. Likewise, the combination of sugarcane molasses and soybean bran hydrolysate was effective for cell growth of a probiotic strain of S. cerevisiae with a 24.08% β-glucan content. The results demonstrated that starchy acid hydrolysates are low-cost and efficient substrates for the production of yeast biomass and derivate products and may contribute to further studies for a sustainable development of biorefinery technologies.

Metabolizable and net energy values of corn stored for 3 years for laying hens

The apparent metabolizable energy (AME), AME corrected to zero-nitrogen retention (AMEn), and net energy (NE) values of 2 corn samples both stored for 3 yr were determined in laying hens with reference diet substitution method. Reference diet was formulated according to standard layer requirement, and test diets contained 50% of corn samples and 50% of the reference diet. Fifty-four Hy-Line Brown hens at the age of 36 wk were used. The heat production and energy metabolism of birds were measured in open-circuit respiratory chambers with 6 replicates (3 birds per replicate) per diet in a randomized design. Birds were fed experimental diets for 7 D in the chamber as adaptation. During the following 3 D, feed intake, metabolizable energy value, nitrogen balance, energy balance, egg production, O₂ consumption, CO₂ production, and energy efficiency were determined. The AME values of corn 1 and corn 2 were 3,485 and 3,675 kcal/kg DM, respectively. The corresponding AMEn values were 3,452 and 3,596 kcal/kg DM, and the NE values were 2,575 and 2,693 kcal/kg DM, respectively. The NE:AME ratios of corn 1 and corn 2 were 74.4 and 73.3%, respectively. The NE:AMEn ratios of corn 1 and corn 2 were 75.0 and 74.9%, respectively. The AME, AMEn, and NE values of the 2 corn samples both stored for 3 yr were lower than the literature values for fresh corn.

Implementation of net energy evaluating system in laying hens: Validation by performance and egg quality

Three experiments were conducted to determine the effect of different dietary net energy (NE) and AMEn ratios (NE:AMEn) on performance, egg quality, and heat production (HP) in laying hens. In experiment 1, 62 Hy-Line Brown hens were fed 2 treatments with 31 replicates from 44 to 54 wk of age. In experiment 2, 600 hens of the same strain were fed 3 treatments from 22 to 42 wk of age with 10 replicates. Both used a completely randomized design. Diets were based on corn, wheat, wheat bran, barley, soybean meal, canola meal, meat and bone meal, and canola oil. In both experiments, the NE:AMEn ratio of diets was increased with higher oil inclusion compared with T1 controls. The AMEn (kcal/kg), NE (kcal/kg), ether extract (g/kg), and CP (g/kg), respectively, on a DM basis in experiment 1 was T1: 3,011, 2,288, 42, 202 and T2: 3,023, 2,374, 81, 203; and in experiment 2, T1: 3,026, 2,324, 25, 187; T2: 2,949, 2,315, 61, 185; and T3: 3,026, 2,397, 73, 181. Increasing the ratio of NE:AMEn decreased feed intake (P < 0.001) and increased egg mass (P < 0.05) in experiment 2 and increased egg weight (P < 0.01), decreased feed conversion ratio (P < 0.01), increased egg albumen % (P < 0.001), and decreased yolk % (P < 0.05) and shell % (P < 0.05) compared with T1 controls in both experiments. Haugh units and yolk color scores were increased with high NE:AMEn in both experiments (P < 0.001; P < 0.01). Experiment 3 was conducted in calorimetry chambers to measure HP in birds fed experiment 2 diets. Increasing the NE:AMEn increased total retained energy (RE), RE as fat, and RE in the body (kcal/kg BW^0.75/D) and NE:AME. The results indicate that using oil to increase the NE:AMEn results in improved performance and egg quality and more efficient energy utilization.

Effects of main cereal type and feed form on production performance, egg quality and egg sanitary indices of laying hens

1. The experiment was conducted to evaluate the effects of cereal types (maize or wheat) and feed forms (pelleted or mash feed) on production performance, egg quality and egg sanitary indices in laying hens.2. Three hundred and sixty hens (Jinghong No. 1) at 18 weeks of age were randomly assigned to four treatments with six replicates of 15 hens per replicate according to a 2 × 2 factorial design with two cereal types (maize or wheat) and two feed forms (pelleted or mash feed).3. Compared with the wheat-based diet, the maize-based diet improved (P < 0.05) average egg weight of laying hens. Yolk colour of hens fed with the maize-based diet was higher (P < 0.05) in comparison to those fed the wheat-based diet, while Haugh units were lower (P < 0.05) for the maize-based treatment. Egg mass and average daily feed intake of hens fed the pelleted diet were higher (P < 0.05) than of those fed the mash diet. However, the mash diet improved (P < 0.05) yolk colour compared with the pelleted diet. The percentage of dirty eggs for the wheat-based diet was higher (P < 0.05) than for the maize-based diet. The percentage of dirty eggs was higher (P < 0.05) in birds fed the pelleted diet compared with those fed the mash diet. There were interactions (P < 0.05) between cereal type and feed form, with regard to average egg weight and shell thickness.4. In conclusion, dietary cereal type affected average egg weight, yolk colour and Haugh units in eggs, while feed form influenced egg mass, average daily feed intake and yolk colour.

Historical flaws in bioassays used to generate metabolizable energy values for poultry feed formulation: a critical review

Dietary energy available to animals is key for formulating feed as it is required for all aspects of the animal's life. In poultry, apparent (AME) and true (TME) metabolizable energy (ME) values have been used for feed formulation with (AMEn or TMEn) or without correction for nitrogen balance. For the past 50 yr, the accuracy of ME has been an ongoing debate, and the comparability of data produced using different bioassay systems is often questionable. Overall, the ingredient matric ME values used in feed formulation are not consistent, and to some extent, confusing. This review was to examine ME data published in the past century to elucidate the accuracy of different bioassay systems and examine the values for accuracy and useability. A variety of flaws are identified in the literature, suggesting a thorough re-thinking of feedstuff ME values currently used in feed formulation and in developing prediction equations. Two protocols, namely multiple linear regression and basal diet substitution methods, are proposed as more accurate bioassays for feedstuff ME values. AME aligns more closely with the actual energy levels of feed ingredients likely available to growing birds, which should be used for poultry feed formulations instead of AMEn. It is suggested that nutritionists need to carefully apply any reported AME values and only use those in formulation practice after careful scrutinizing. Any in vitro, NIR or table values must be calibrated or computed based on the values produced from flawless bioassays so as to apply the derived values accurately. Flaws identified in this literature review can be avoided with care to achieve more accurate AME. However, the assumption that the energy of individual ingredients is additive in a complete diet is still untrue at least under some circumstances. This may require efforts from industry and researchers to investigate relations among the main ingredients in a complete diet so that more accurate formulation can be performed based on the outcomes that may fine-tune the additivity assumption.