Application of Apparent Metabolizable Energy versus Nitrogen-Corrected Apparent Metabolizable Energy in Poultry Feed Formulations: A Continuing Conundrum

Estimation of the digestible energy value of fat obtained from black soldier fly larvae (Hermetia illucens) for growing pigs

An experiment was conducted to determine the digestible energy (DE) of insect fat (IF) from black soldier fly larvae (BSLF) for growing pigs. Saturated fatty acids (SFA) were the dominant group of fatty acids in the IF, with lauric acid (C12:0) and palmitic acid (C16:0) comprising the greatest concentrations in this group. Linoleic acids (C18:2) and oleic acids (C18:1) were the main unsaturated fatty acids. The IF contained 37.63 MJ/kg gross energy and 2.55 g/kg nitrogen. During the experiment, a DE bioassay was performed wherein growing pigs were fed one of the two experimental diets (either a maize-wheat-barley-soy basal diet or a diet containing 50 g/kg IF plus 950 g/kg of the basal diet). The DE of the IF was calculated based on the differences between the DE values of basal and test diet (substitution method). The DE of the IF was determined to be 36.86 MJ/kg. The IF contains a DE level comparable to vegetable oils, including soybean, rapeseed, corn and palm oils. The results showed that the examined fat from BSLF is a good source of available energy and can be incorporated in pig diets as an alternative energy source.

Amino acid and energy digestibility of conventional corn dried distillers grains with solubles, high protein distillers dried grains, and corn fermented protein, and impacts on turkey poult growth performance and intestinal characteristics

Amino acids (AA) are an expensive nutritional components of poultry diets. Distillers dried grains with solubles (DDGS) is the primary co-product produced by the dry grind bioethanol industry, although new technologies are being implemented to produce high protein distillers dried grains (HP-DDG) and corn fermented protein (CFP), but data on their nutritive value in poultry are lacking. Two experiments (EXP) were conducted to determine the energy and AA digestibility of DDGS, HP-DDG, and CFP in poults in addition to a feeding trial to evaluate increasing dietary levels of HP-DDG and CFP on growth performance and intestinal characteristics. In EXP 1, 6 different DDGS sources were evaluated using poults to determine their nitrogen-corrected apparent metabolizable energy (AMEn) concentrations, and cecectomized roosters were used to determine their standardized ileal (SID) AA digestibility (SID-AA). In EXP 2, AMEn and SID-AA for HP-DDG and CFP were determined in young poults, and a feeding trial was conducted to evaluate growth performance and intestinal morphology and permeability of poults fed diets containing 7.5 and 15% HP-DDG or CFP from 1 to 32 d of age. In EXP 1, the AMEn concentration among the DDGS samples ranged from 2,530 to 3,573 kcal/kg DM but was not different (P = 0.57) among the samples, with an average SID for LYS of 66.6%. In EXP 2, different (P = 0.001) AMEn concentrations for HP-DDG and CFP were observed (3,114 and 3,760 kcal/kg DM, respectively), with the SID for LYS being 66.55 and 77.00% for HP-DDG and CFP, respectively. Including HP-DDG or CFP into the diet at 7.5 and 15% had no effect (P > 0.05) on growth, feed intake, or feed conversion. Neither co-product nor its inclusion rate affected intestinal morphology and permeability (P > 0.05). Overall, DDGS, HP-DDG, and CFP are excellent sources of AMEn and digestible AA, with dietary inclusion rates of up to 15% of HP-DDG or CFP having no impact on growth or intestinal characteristics.

Full-Fat Soybean Meals as an Alternative Poultry Feed Ingredient-Feed Processing Methods and Utilization-Review and Perspective

On a global scale, the poultry industry expands its wings in terms of meat and egg production to the masses. However, this industry itself requires a sustainable and permanent supply of different inputs, one of which is poultry feed and nutrition. Soybean is a versatile protein that is offered to poultry in different inclusion rates in commercial diets after being processed using various thermal and mechanical processing methods. Conventional commercial soybean meal is usually prepared by the extraction of oil from whole soybeans using solvents, producing a meal that has approximately 1% crude fat. Without oil extraction, full-fat soybean (FFSBM) is produced, and it is an excellent source of dietary energy and protein for poultry with a nutritional profile of 38-40% protein and 18-20% crude fat, on average. FFSBM has less crude protein (CP) than solvent-extracted soybean meal (SE SBM) but higher metabolizable energy due to higher fat content. Alternatively, extruded expeller processing produces defatted soybean meal containing approximately 6-7% crude fat. Studies have demonstrated that FFSBM can be used in poultry diets to improve poultry nutrition, performance, and quality of the poultry meat and eggs produced. This review aims to evaluate the nutrition and use of meals prepared from conventional and high-oleic soybeans using various feed processing methods.

Apparent metabolizable energy and ileal amino acid digestibility of commercial soybean meals of different origins in broilers

We studied the chemical composition and the in vivo AMEn content and apparent (AID) and standardized (SID) ileal digestibility of CP and amino acids (AA) of 27 samples of soybean meals (SBM) from Argentina (ARG), Brazil (BRA), and USA, collected in Spain. On 88% DM basis, the BRA meals had more CP (46.9 vs. 46.0 and 45.9%; P < 0.05) and less sucrose (5.21 vs. 6.28 and 6.47%; P < 0.001) and stachyose (4.20 vs. 4.66 and 4.78%; P < 0.05) than the USA and ARG meals. Urease activity, protein dispersibility index, KOH protein solubility, and trypsin inhibitor activity values, were higher for the USA meals than for the South American meals (P < 0.05). In the in vivo trial, broilers received a common crumble diet from 0 to 16 d of age and then, their respective experimental diets (53% of a N-free diet and 47% of each of the 27 SBM tested) in mash form, for 5 d. The AMEn (2,334 vs. 2,282 and 2,277 kcal/kg; P = 0.062) and the AID (87.3 vs. 86.7 and 86.4%; P = 0.054) and SID (91.9 vs. 91.2 and 90.8%; P < 0.05) of the protein, were greater for the USA meals than for the ARG and BRA meals. In fact, the SID of Lys (93.5 vs. 93.0 and 92.1%; P < 0.001) and of the sum of Lys, Met, Thr, Trp, and Cys (91.4 vs. 91.0 and 90.2%; P < 0.05) were greater for the USA meals than for the ARG and BRA meals. In summary, the chemical composition, protein quality indicators, AMEn content, and ileal digestibility of the CP and the AA of the SBM, varied with the country of origin of the soybeans. In order to increase the accuracy of the feed formulation process, the composition and nutrient content of commercial batches of SBM, by country of origin should be controlled and periodically updated.

Investigations into the chemical composition and nutritional value of different batches of rapeseed meals for turkey poults

A study was conducted to investigate the chemical composition and feeding value of rapeseed meal (RSM) batches produced at the same plant when fed to turkey poults. In total, seven RSM samples were obtained from a single manufacturer within a period of 90 days. Although the manufacturer followed the same procedures during oil extraction and RSM production, different batches of rapeseed were used. A balancer feed (BF) was formulated to contain 11.85 MJ/kg ME and 265 g/kg crude protein. Seven nutritionally complete test mash diets were prepared by mixing 200 g/kg of each RSM batch sample with 800 g/kg of the BF, totalling 8 diets. Diets were fed to female B.U.T. Premium turkeys from 12 to 21 d of age. Each diet was fed to six raised floor pens, housing two birds, following randomisation. During the experiment, a nitrogen corrected apparent metabolisable energy (AMEn) assay was performed using a total collection technique. The AMEn in RSM samples was calculated based on the differences between the AMEn values of basal and test diets. Associations were examined between AMEn and the chemical composition of the RSM samples. The overall determined AMEn value of the RSM ranged from 5.50 MJ/kg DM to 8.53 MJ/kg DM, giving an average AMEn of 7.29 MJ/kg DM. There was no difference (p > 0.05) in AMEn content between batches. There was a negative correlation (r = - 0.864; p < 0.05) between AMEn values and the neutral detergent fibre (NDF) content of the RSM samples. The results suggest that the NDF could be a good predictor of the AMEn of industry produced RSM. It may be inferred that processing rather than cultivar could be the main factor determining the feeding value of RSM for turkeys.

Re-evaluation of recent research on metabolic utilization of energy in poultry: Recommendations for a net energy system for broilers

Different energy systems have been proposed for energy evaluation of feeds for domestic animals. The oldest and most commonly used systems take into account the fecal energy loss to obtain digestible energy (DE), and fecal, urinary and fermentation gases energy losses to calculate metabolizable energy (ME). In the case of ruminants and pigs, the net energy (NE) system, which takes into account the heat increment associated with the metabolic utilization of ME, has progressively replaced the DE and ME systems over the last 50 years. For poultry, apparent ME (AME) is used exclusively and NE is not yet used widely. The present paper considers some important methodological points for measuring NE in poultry feeds and summarizes the available knowledge on NE systems for poultry. NE prediction equations based on a common analysis of three recent studies representing a total of 50 complete and balanced diets fed to broilers are proposed; these equations including the AME content and easily available chemical indicators have been validated on another set of 30 diets. The equations are applicable to both ingredients and complete diets. They rely primarily on an accurate and reliable AME value which then represents the first limiting predictor of NE value. Our analysis indicates that NE would be a better predictor of broiler performance than AME and that the hierarchy between feeds is dependent on the energy system with a higher energy value for fat and a lower energy value for protein in an NE system. Practical considerations for implementing such an NE system from the commonly used AME or AMEn (AME adjusted for zero nitrogen balance) systems are presented. In conclusion, there is sufficient information to allow the implementation of the NE concept in order to improve the accuracy of feed formulation in poultry.

Influence of extruded soybean meal with varying fat and oleic acid content on nitrogen-corrected apparent metabolizable energy in broilers

High oleic (HO) soybeans may serve as a value-added feed ingredient; providing amino acids and estimating their dietary energy value for broilers is essential. In this study, we determined the apparent metabolizable energy (AME), AME corrected for zero nitrogen retention (AMEn), digestibility, and nitrogen (N) retention of HO full-fat (HO-FF) soybean as compared to solvent-extracted soybean meal (SE-SBM), normal oleic full-fat (NO-FF) and extruded expeller (NO-EE) soybean. A total of 240 Ross-708 male broilers were selected, with 8 replicates per treatment and 6 chicks per cage. The AME and AMEn were estimated using the difference method with a 30% inclusion of test ingredients using a corn-soy reference diet with partial and total excreta collection. The index method with partial excreta collection used titanium dioxide as an inert marker. The same starter diet was provided for all birds for 14 d, followed by the reference and assay diets for the next 6 adaptation days. Total excreta were collected twice a day for 3 d. The AME and AMEn values determined for the HO-FF and NO-FF were higher (P < 0.001) than the NO-EE and SE-SBM. The AME of SE-SBM and NO-EE were similar with both methods, but the AMEn of SE-SBM was lower than the NO-EE only with the partial collection method. The agreement between AME and AMEn values determined by partial and total excreta collection analysis was 98%. Data from the total excreta collection method yielded higher AME and AMEn values (P < 0.001) than those from the partial collection method. In summary, HO-FF and NO-FF soybean meals had similar AME and AMEn values. The HO-FF soybean had 39 and 24% higher AME and AMEn than SE-SBM. Hence, high oleic full-fat soybean meal could serve as a valuable alternative feed ingredient to conventional SE-SBM meals in broiler diets, providing additional energy while providing amino acids and more oleic acid to enrich poultry meat products.

Carbohydrate-active enzymes in animal feed

Considering an ever-growing global population, which hit 8 billion people in the fall of 2022, it is essential to find solutions to avoid the competition between human food and animal feed for croplands. Agricultural co-products have become important components of the circular economy with their use in animal feed. Their implementation was made possible by the addition of exogenous enzymes in the diet, especially carbohydrate-active enzymes (CAZymes). In this review, we describe the diversity and versatility of microbial CAZymes targeting non-starch polysaccharides to improve the nutritional potential of diets containing cereals and protein meals. We focused our attention on cellulases, hemicellulases, pectinases which were often found to be crucial in vivo. We also highlight the performance and health benefits brought by the exogenous addition of enzymatic cocktails containing CAZymes in the diets of monogastric animals. Taking the example of the well-studied commercial cocktail Rovabio™, we discuss the evolution, constraints and future challenges faced by feed enzymes suppliers. We hope that this review will promote the use and development of enzyme solutions for industries to sustainably feed humans in the future.

Broiler Age Influences the Apparent Metabolizable Energy of Soybean Meal and Canola Meal

The effects of broiler age on the apparent metabolizable energy (AME) and nitrogen-corrected AME (AMEn) of soybean meal (SBM) and canola meal (CM) were examined. A corn-SBM basal diet was developed, and two test diets were formulated by substituting (w/w) 300 g/kg of the basal diet with SBM or CM. Six groups of broiler chickens, aged 1−7, 8−14, 15−21, 22−28, 29−35 or 36−42 d post-hatch, were utilized. Each diet, in pellet form, was randomly allocated to six replicate cages in each age group. Except for the 1−7 d age group, the birds were fed a starter (d 1−21) and/or a finisher (d 22−35) diet prior to the introduction of the experimental diets. The number of birds per cage was 10 (d 1−7), 8 (d 8−14) and 6 (d 15−42). The AME and AMEn of SBM and CM were determined by total excreta collection. The data for each protein source were subjected to orthogonal polynomial contrasts using the General Linear Models procedure. Bird age decreased the retention of dry matter quadratically (p < 0.001) for both SBM and CM. The retention of nitrogen decreased linearly (p < 0.001) with the advancing age of broilers for SBM and CM. The AMEn of SBM and CM decreased quadratically (p < 0.001) as the birds grew older. The highest AMEn was observed during week 1 for both SBM and CM, then declined until week 3, followed by increases thereafter. The current results showed that the age of broiler chickens influenced the AMEn of SBM and CM and supported the use of age-dependent AMEn of feed ingredients in diet formulations.

The apparent metabolisable energy requirement of Sansui ducks from hatch to 21 days of age

A dose-response experiment was conducted to estimate optimal dietary apparent metabolisable energy requirement (AME) in Sansui ducks (Sansui Sheldrake duck) from hatch to 21 days of age. Three hundred thirty-six one-day-old male Sansui ducks were randomly assigned to six experimental treatments, each consisting of seven replicate pens with eight birds per pen. Birds were fed diets containing either 10.92, 11.38, 11.8, 12.26, 12.68 and 13.14 MJ AME/kg, respectively. At 21 d of age, the body weight, weight gain, feed intake, protein intake, energy intake and feed conversion ratio of ducklings from each pen were measured. Increasing AME content from 10.92 MJ/kg to 13.14 MJ/kg significantly improved body weight, weight gain, feed intake, feed conversion ratio and crude protein intake (P<0.05). No significant changes in energy intake were found among treatments (P>0.05). Based on broken-line regression analysis, the AME requirement of male Sansui ducks from hatch to 21 d of age was 11.49 and 11.59 MJ/kg for maximum body weight and best feed conversion ratio, respectively.

Metabolizable energy and standardized ileal amino acid digestibility of full-fat soybeans for broilers are influenced by wet-heating, expansion temperature, and autoclaving time

The influence of wet-heating (WH) and expansion temperature (ET), and autoclaving time (AT) on the nitrogen-corrected apparent metabolizable energy (AME_n) and standardized ileal digestibility (SID) of AA in full-fat soybeans (FFSB) for broilers was examined in 2 experiments. The AME_n and SID AA of FFSB were determined by the difference and direct methods, respectively. In Experiment 1, raw FFSB (K0) were either treated by WH at 80°C for 1 min and expanded at 115°C (K1-115) or 125°C (K1-125), WH at 100°C for 6 min and expanded at 115°C (K2-115) or 125°C (K2-125), or WH at 100°C for 16 min and expanded at 115°C (K3-115) or 125°C (K3-125). Wet-heating and ET significantly (P < 0.001) increased the AME_n in FFSB. Among heat-treated FFSB, K1-115 and K1-125 resulted in the lowest and highest AME_n values, respectively, with all samples wet-heated at 100°C being intermediate. The K3-125 had AME_n values similar (P > 0.05) to K1-125. Among heat-treated FFSB, the highest average SID AA was recorded for K3-125. In Experiment 2, K3-125 from experiment 1 was divided into 9 batches and autoclaved at 110°C for 15 (Z1), 30 (Z2), 45 (Z3), 60 (Z4), 120 (Z5), 180 (Z6), 240 (Z7), 300 (Z8), and 360 (Z9) min. A quadratic (P < 0.01) pattern was observed for the effects of AT on AME_n. The AME_n was unaffected until 300 min AT and then declined at 360 min. The AT quadratically (P < 0.001) affected the average SID AA where the SID increased from K3-125 to Z1, plateaued to Z5, and then declined to Z9. In conclusion, the results demonstrated that WH at 100°C for 16 min followed by expansion at 125°C as the most optimal wet-heating and expansion processing, associated with the highest SID AA. Autoclaving at 110°C for 30 min enhanced energy utilization and AA digestibility in FFSB, suggesting that further advantages may be achieved by short-time autoclaving of previously wet-heated and expanded FFSB samples.

Autoclaving time-related reduction in metabolizable energy of poultry meal is greater in growing pigs compared with broiler chickens

The objective of this study was to determine the energy utilization responses of growing pigs and broiler chickens to poultry meal that was autoclaved at 134 °C for 0 to 180 min. Poultry meal from the same batch was autoclaved at 134 °C for 7 autoclaving times of 0, 30, 60, 90, 120, 150, or 180 min to generate 7 samples. Eight experimental diets consisting of a basal diet based on corn and soybean meal, and seven test diets in which 15% of energy-contributing ingredients in the basal diet were replaced with each of the seven poultry meal samples were used. In experiment 1, there were 64 barrows (initial body weight = 19.4 ± 1.0 kg) allotted to 8 experimental diets in a randomized complete block design with body weight as a blocking factor. Each pig received an experimental diet during 5 d of adaptation followed by 5 d of quantitative total, but separate, collection of urine and feces. In experiment 2, a total of 512 male broiler chickens at day 17 post-hatching (initial body weight = 660 ± 80 g) in 8 replicate cages were allotted to 8 experimental diets in a randomized complete block design with body weight as a blocking factor. Excreta were collected from days 20 to 22 post-hatching, and birds were euthanized by CO2 asphyxiation for ileal digesta collection. Data from experiments 1 and 2 were pooled together for statistical analysis as a 2 × 7 factorial treatment arrangement with the effect of species (pigs or broiler chickens) and autoclaving time of poultry meal (7 autoclaving times between 0 and 180 min). An interaction between species and their linear effect of autoclaving time was observed (P < 0.05) in metabolizable energy (ME) of poultry meal. Specifically, linear decrease in ME values in poultry meal with increasing autoclaving time was greater (P < 0.05) in growing pigs (4,792 to 3,897 kcal/kg dry matter) compared with broiler chickens (3,591 to 3,306 kcal/kg dry matter). The ME value of unautoclaved poultry meal was greater (P < 0.01) for pigs than broiler chickens at 4,792 vs. 3,591 kcal/kg dry matter. Although decrease in ME values with autoclaving time of poultry meal was greater in growing pigs than in broiler chickens, the ME in autoclaved poultry meal fed to pigs was greater than ME in non-autoclaved poultry meal fed to broiler chickens. Furthermore, the ratio of cysteine to crude protein concentration is a potential indicator for estimating the ratio of ME to gross energy in poultry meal for growing pigs (r2 = 0.81) and broiler chickens (r2 = 0.84).