Nitrogen-corrected True Metabolizable Energy Research Articles

PSVIII-18 Standardized Amino Acid Digestibility and Nitrogen-Corrected True Metabolizable Energy of Frozen Raw, Freeze-Dried Raw, Fresh, and Extruded Dog Foods Using Cecectomized and Conventional Rooster Assays

Abstract Processing conditions, particularly temperature and duration of heating, impact the digestibility of pet foods. Various alternative commercial pet food formats are now available, but few have been well tested. Therefore, the objective of this study was to determine the amino acid (AA) digestibility and nitrogen-corrected true metabolizable energy (TMEn) of frozen raw, freeze-dried raw, fresh, and extruded dog foods using the precision-fed cecectomized and conventional rooster assays. The diets tested were Chicken and Barley Recipe [extruded diet; Hill’s Science Diet (EXT)], Chicken and White Rice Recipe [fresh diet; Just Food for Dogs (FRSH], Chicken Formula [raw frozen diet; Primal (FRZN)], Chicken and Sorghum Hybrid Freeze-dried Formula [hybrid freeze-dried raw diet; Primal (HFD)], and Chicken Dinner Patties [raw freeze-dried diet; Stella & Chewy (FD)]. Two precision-fed rooster assays utilizing Single Comb White Leghorn roosters (1.5 to 2.5 yr, 2.5 to 3 kg) were conducted. In the first assay, 20 cecectomized roosters (n = 4/treatment) were used to determine AA digestibility. In the second assay, 20 conventional roosters (n = 4/treatment) were used to determine TMEn. In both assays, roosters were crop intubated with 12 g of test diet and 12 g of corn, and then excreta were collected for 48 h. The reactive lysine:total lysine ratios were 0.94, 0.96, 0.93, 0.93, and 0.95 for the EXT, FRSH, FRZN, HFD, and FD diets, respectively. In general, FD had the greatest AA digestibilities and EXT had the least AA digestibilities. Arginine digestibilities were different (P < 0.05) across all diets and in this pattern: FD > FRZN > FRSH > HFD > EXT. Isoleucine digestibilities were different (P < 0.05) across all diets, but with a slightly different pattern: FD > FRZN > FRSH > EXT > HFD. Lysine digestibility was greater (P < 0.05) in FD and FRZN than EXT, with other diets being intermediate. Methionine digestibility was greater (P < 0.05) in FD than FRSH, with other diets being intermediate. Threonine digestibility was greater (P < 0.05) in FD than EXT, with other diets being intermediate. Valine digestibilities were different (P < 0.05) across all diets and in this pattern: FD > FRZN > EXT > FRSH > HFD. Digestibilities of the other essential AA were not different among diets. TMEn was greater (P < 0.05) in FRZN than FD, FRSH, and EXT, greater (P < 0.05) in HFD than FRSH and EXT, and greater (P < 0.05) in FD than EXT. In conclusion, our results support the notion that diet processing impacts AA digestibility, with freeze-dried raw, frozen raw, and fresh diets consistently having greater digestibility coefficients, as well greater TMEn, than the extruded diet. More research in dogs is necessary to test the effects of these diet formats on palatability, digestibility, stool quality, and other physiologically relevant outcomes.

Standardized amino acid digestibility and nitrogen-corrected true metabolizable energy of frozen and freeze-dried raw dog foods using precision-fed cecectomized and conventional rooster assays.

Commercial raw or minimally-processed diets, often referred to holistically as raw meat-based diets (RMBD) represent a small portion of the pet food market, but the growth of this sector has been significant in recent years. While traditionally, high-moisture, frozen options were the standard format of commercially available raw diets, freeze-dried raw diets have become more prevalent as of late. Despite the increasing popularity of these commercial raw diet formats, there is a dearth of literature describing their nutritional properties, particularly regarding freeze-dried diets. Therefore, the objective of this experiment was to determine and compare the standardized amino acid (AA) digestibilities and nitrogen-corrected true metabolizable energy (TMEn) of raw frozen and freeze-dried dog foods using precision-fed cecectomized and conventional rooster assays. Three formats of frozen or freeze-dried raw diets provided by Primal Pet Foods (Fairfield, CA, USA) were tested: traditional freeze-dried nuggets (T-FDN), hybrid freeze-dried nuggets (H-FDN), and frozen nuggets (FZN). Diets were fed to cecectomized roosters (4 roosters/diet) to determine AA digestibilities, while conventional roosters (4 roosters/diet) were used to determine TMEn. In both cases, after 26 h of feed withdrawal, roosters were tube-fed 12 to 13 g of test diets and 12 to 13 g of corn. Following crop intubation, excreta were collected for 48 h. Endogenous corrections for AA were made using five additional cecectomized roosters. All data were analyzed using the Mixed Models procedure of SAS version 9.4. There were no significant differences in standardized AA digestibilities among diets, with digestibilities being high for all diets tested. For most of the indispensable AA, digestibilities were greater than or equal to 90% for all diets. Histidine and lysine were the exceptions, with digestibilities ranging from 82% to 87% and 87% to 92%, respectively. Moreover, the reactive lysine:total lysine ratio, a measure of heat damage, ranged from 0.91 to 0.95. TMEn values were higher (P = 0.0127) in T-FDN (6.1 kcal/g) and FZN (5.9 kcal/g) than H-FDN (5.3 kcal/g) and were most similar to those estimated by Atwater factors. In general, all diets tested had high AA digestibilities and had TMEn values that were most similar to Atwater factors.

Standardized amino acid digestibility and nitrogen-corrected true metabolizable energy of frozen raw, freeze-dried raw, fresh, and extruded dog foods using precision-fed cecectomized and conventional rooster assays.

Processing conditions, particularly temperature and duration of heating, impact pet food digestibility. Various commercial pet food formats are now available, but few have been tested thoroughly. The objective of this study was to determine the amino acid (AA) digestibilities and nitrogen-corrected true metabolizable energy (TMEn) values of frozen raw, freeze-dried raw, fresh (mildly cooked), and extruded dog foods using the precision-fed cecectomized and conventional rooster assays. The diets tested were Chicken and Barley Recipe [Hill's Science Diet, extruded diet (EXT)], Chicken and White Rice Recipe [Just Food for Dogs, fresh diet (FRSH)], Chicken Formula [Primal Pet Foods, frozen raw diet (FRZN)], Chicken and Sorghum Hybrid Freeze-dried Formula [Primal Pet Foods, hybrid freeze-dried raw diet (HFD)], and Chicken Dinner Patties [Stella & Chewy's, freeze-dried raw diet (FD)]. Two precision-fed rooster assays utilizing Single Comb White Leghorn roosters were conducted. Cecectomized roosters (n = 4/treatment) and conventional roosters (n = 4/treatment) were used to determine standardized AA digestibilities and TMEn, respectively. All roosters were crop intubated with 12 g of test diet and 12 g of corn, with excreta collected for 48 h. In general, FD had the highest, while EXT had the lowest AA digestibilities; however, all diets performed relatively well and few differences in AA digestibility were detected among the diets. Lysine digestibility was higher (P < 0.05) in FD and FRZN than EXT, with other diets being intermediate. Threonine digestibility was higher (P < 0.05) in FD than EXT, with other diets being intermediate. Digestibilities of the other indispensable AA were not different among diets. The reactive lysine:total lysine ratios were 0.94, 0.96, 0.93, 0.93, and 0.95 for EXT, FRSH, FRZN, HFD, and FD, respectively. TMEn was higher (P < 0.05) in FRZN than FD, FRSH, and EXT, higher (P < 0.05) in HFD than FRSH and EXT, and higher (P < 0.05) in FD than EXT. In conclusion, our results support the notion that AA digestibilities are affected by diet processing, with FD, HFD, FRZN, and FRSH diets having higher AA digestibility coefficients and greater TMEn values, than the EXT diet; however, other factors such as ingredient inclusion and macronutrient composition may also have affected these results. More research in dogs is necessary to test the effects of format on diet palatability, digestibility, stool quality, and other physiologically relevant outcomes.

Amino acid digestibility and nitrogen-corrected true metabolizable energy of mildly cooked human-grade vegan dog foods using the precision-fed cecectomized and conventional rooster assays.

The pet food market is constantly changing and adapting to meet the needs and desires of pets and their owners. One trend that has been growing in popularity lately is the feeding of fresh, human-grade foods. Human-grade pet foods contain ingredients that have all been stored, handled, processed, and transported in a manner that complies with regulations set for human food production. While most human-grade pet foods are based on animal-derived ingredients, vegan options also exist. To our knowledge, no in vivo studies have been conducted to analyze the performance of human-grade vegan diets. Therefore, the objective of this study was to investigate the amino acid (AA) digestibility and nitrogen-corrected true metabolizable energy (TME n ) of mildly cooked human-grade vegan dog foods using precision-fed cecectomized rooster and conventional rooster assays. Three commercial dog foods were tested. Two were mildly cooked human-grade vegan dog diets (Bramble Cowbell diet (BC); Bramble roost diet (BR)), while the third was a chicken-based extruded dog diet (chicken and brown rice recipe diet (CT)). Prior to the rooster assays, both mildly cooked diets were lyophilized, and then all three diets were ground. Diets were fed to cecectomized roosters to determine AA digestibility, while conventional roosters were used to determine TME n . All data were analyzed using the mixed models procedure of SAS (version 9.4). The majority of indispensable and dispensable AA across all diets had digestibilities higher than 80%, with a few exceptions (BC: histidine, lysine, threonine, and valine; BR: histidine). The only difference in indispensable AA digestibility among diets was observed with tryptophan, with its digestibility being higher (P = 0.0163) in CT than in BC. TME n values were higher (P = 0.006) in BC and BR (4.55 and 4.66 kcal/g dry matter, respectively) than that in CT (3.99 kcal/g dry matter). The TME n /GE was also higher (P = 0.0193) in BR than in CT. Metabolizable energy (ME) estimates using Atwater factors accurately estimated the energy content of CT, but modified Atwater factors and the predictive equations for ME recommended by the National Research Council underestimated energy content. All calculations underestimated the measured TME n values of BC and BR, with Atwater factors being the closest. Although testing in dogs is required, these data suggest that mildly cooked human-grade vegan dog diets are well-digested. Moreover, TME n data suggest that existing methods and equations underestimate the ME of the mildly cooked human-grade vegan foods tested.

Evaluation of the precision-fed rooster assay for detecting effects of supplemental enzymes on metabolizable energy

The precision-fed rooster assay has been used extensively to determine nitrogen-corrected true metabolizable energy (TMEn) of feed ingredients for poultry. However, this assay has not generally been used to evaluate effects of supplemental enzymes for this purpose. Therefore, 2 precision-fed rooster assays were conducted to evaluate several different carbohydrase enzymes on TMEn for a corn/soybean meal diet, a pearled barley diet, and diets containing different inclusion levels of rye/corn. In both rooster assays, Single Comb White Leghorn roosters were fasted for 26 h and then crop intubated with either 25 or 30 g of the test diets, depending on the assay. Excreta were then collected quantitatively for 48 h after feeding. In the first rooster assay with 56 birds, 6 carbohydrase combinations and/or levels (xylanase/alpha-galactosidase were evaluated using a corn/soybean meal control diet. All carbohydrase additions either numerically or significantly (P < 0.05) increased TMEn and the mean increase for the enzyme treatments was 66 kcal/kg DM compared with the corn/soybean meal control diet. The second assay consisted of twenty dietary treatments; 120 roosters were crop-intubated with 25 g of diets that were composed of 100% barley, 100% rye, 50% rye: 50% corn, or 25% rye: 75% corn. The diets were fed with and without inclusion of 2 different levels of either β-glucanase, xylanase, or a multi-carbohydrase combination. Both β-glucanase and the multi-carbohydrase significantly (P < 0.05) increased TMEn of the 100% barley diet, with the multi-carbohydrase increasing it from 3,722 to 4,086 kcal/kg DM at the highest inclusion rate. The xylanase and multi-carbohydrase either numerically or significantly (P < 0.05) increased TMEn of the 100% rye diet, with the multi-carbohydrase increasing it from 3,581 to 3,909 kcal/kg DM at the highest inclusion rate. The magnitude of enzyme response decreased as the level of rye in the diets decreased. Overall, results of this study indicated that the precision-fed rooster assay can detect effects of enzymes, primarily carbohydase, on TMEn of diets containing corn/soybean meal, pearled barley, and/or rye.

Nutrient profile and effects of carinata meal as alternative feed ingredient on broiler performance, tight junction gene expression and intestinal morphology

Two studies were conducted to establish carinata meal as a partial replacement of conventional protein sources. Study I was conducted to determine the nutrient profile, nitrogen-corrected true metabolizable energy (TMEn), and amino acid (AA) digestibility of 2 groups: low glucosinolate carinata meal (LGCM) and high glucosinolate carinata meal (HGCM) using rooster assays. The LGCM contained 28 μmol/g glucosinolate, 11.5% moisture, 39.2% crude protein (CP), whereas the HGCM had 100 μmol/g glucosinolate, 10.1% moisture, 39.5% CP on as is basis. The precision-fed rooster assays were conducted to determine TMEn and AA digestibility. The TMEn levels of LGCM and HGCM were 1,814 and 1,690 kcal/kg on as is basis, respectively. Standardized digestibility for lysine, methionine, cysteine, threonine, and valine were 72, 88, 69, 75, and 79% for LGCM and 80, 89, 71, 76, and 80% for HGCM, respectively. Based on the nutrient profiles from study I, study II was conducted to evaluate the effects of LGCM and HGCM in broilers. A total of 504 one-day-old Cobb500 male broiler chickens were randomly divided into 42 battery cages with 6 replicates of 12 birds per cage. The seven dietary treatments were control diet, 3 inclusion levels of LGCM (4, 8, and 12%), and 3 of HGCM (4, 8, and12%) in a corn-SBM based diet fed for 21 d. No significant differences in BW, BWG, and FI were observed except for significantly lower BWG in 12% HGCM group compared to control for 14-21 days (P < 0.05). The FCR for 12% HGCM increased significantly compared to 4 and 8% of both LGCM and HGCM groups during wk 3 (14–21 d). Based on these studies, carinata meal could be recommended to partially replace conventional feed ingredients at a rate of 12% when LGCM is used and 8% when HGCM is used with no deleterious effects on growth performance, gut histology, and tight junction proteins.

True metabolizable energy and amino acid digestibility in black soldier fly larvae meals, cricket meal, and mealworms using a precision-fed rooster assay

Six precision-fed rooster assays were conducted to determine nutrient composition, nitrogen-corrected true metabolizable energy (TMEn) and standardized amino acid digestibility for three black soldier fly larvae meals (BSFL), one partially-defatted BSFL, one cricket meal and two mealworm meals. The TMEn values were determined in three 48-h rooster assays using conventional roosters and the standardized amino acid digestibility values were determined in three 48-h rooster assays using cecectomized roosters. Nutrient analysis (DM basis) of the meals indicated that the CP varied from 45 to 58% among the four BSFL, was 67% for the cricket meal and varied from 51 to 56% for the two mealworms. Crude fat (12–30%), total P (0.7–1.1%), Ca (0.04–3.6%), and neutral detergent fiber (10–36%) also varied among the insect meals. The TMEn values for the three BSFL were generally consistent and averaged 4079 kcal/kg DM. As expected, partially-defatted BSFL contained a lower level of TMEn. The TMEn of the cricket meal was 4223 kcal/kg DM. Due to their low fiber content and high fat content, the TMEn values for the two mealworms were high and in excess of 5000 kcal/kg DM. Amino acid concentrations of the various insect meals ranged from 0.69 to 1.1% for methionine, 0.57 to 0.73% for cystine, 3.3 to 4.5% for lysine, and 1.9 to 2.6% for threonine. Standardized amino acid digestibility values were generally high (most were 85–95%) for the four BSFL and two mealworms. Digestibility values for most amino acids were slightly lower for the cricket meal. Digestibility of cystine and valine were generally lower and more variable than other amino acids in the seven insect meals. The results of this study indicated that nutrient composition varies substantially among different insect meals, but all insect meals contained high levels of TMEn and digestible amino acids compared with feed ingredients commonly used in poultry diets.

Effect of almond hulls as an alternative ingredient on broiler performance, nutrient digestibility, and cecal microbiota diversity

The objective of this study was to evaluate 2 types of almond hulls (prime hulls and California-type hulls) as alternative feed ingredients for broilers. A total of 560 one-day-old Cobb male chicks were randomly placed to 7 experimental treatments with 8 replicates of 10 birds each. Seven treatments consisted of a corn-soybean meal control diet and diets containing prime hulls or California-type hulls at 3, 6, and 9%. The nitrogen-corrected true metabolizable energy, crude protein, and crude fiber from prime hulls and California-type hulls were 1,624 and 1,514 kcal/kg, 4.8 and 5.0%, and 13.1 and 26.45%, respectively. During 0–19 d of age, the inclusion of the prime hulls at 3 levels had no significant effects on growth performance, but the California-type hulls at 9% increased feed intake (P = 0.02) and feed conversion ratio (P < 0.01), compared with control. The prime hulls at 9% decreased (P < 0.01) ileal dry matter and ileal nitrogen digestibility, and the California-type hulls at 9% only decreased ileal dry matter digestibility, but both prime hulls and California-type hulls at 6% had no effects on ileal dry matter digestibility and nitrogen-corrected apparent metabolizable energy compared to control. In addition, inclusion of prime hulls at 3% decreased (P < 0.01) AMEn compared with control group. There were no significant differences in cecal microbiota diversity at a phylum or genus level among treatments, but 9% inclusion rate of the California-type hulls increased (P < 0.05) the population of certain bacteria in the genus Clostridium and Oscillospira compared with control. In conclusion, as a dietary energy and fiber source, the prime hulls can be used at up to 9% without a negative effect on body weight gain, whereas the California-type hulls can be used up to 6%.

Impact of an alternate feeding program on broiler breeder pullet behavior, performance, and plasma corticosterone

Broiler breeders are commonly feed restricted using some variation of skip-a-day feeding to prevent excessive body weight (BW) gain and poor flock uniformity that results in lower production levels. However, the level of feed restriction has increased leading to negative effects on broiler breeder welfare. Research needs to be conducted to evaluate alternative feeding programs to diminish the negative impact of restricted feeding on bird welfare. This research examined pullets that were fed soybean hulls (alternate day feeding, ATD) on the off day of a traditional skip-a-day feeding program in comparison to the standard skip-a-day program (SAD). The 2 dietary feeding treatments each had 3 replicate pens of 210 pullets each and were fed from wk 5 to 21 of age. Nitrogen-corrected true metabolizable energy and digestible amino acid coefficients of soybean hulls were determined. Body weight in the ATD feed program was significantly higher (P < 0.001) than the birds on the SAD feed program until 16 wk of age. Feed allocations for the SAD feeding program was increased at 11 wk of age to achieve similar BW prior to photo stimulation. The ATD feed program significantly improved BW uniformity of the birds for weeks 8, 12, 16, and 20. Hens fed on the SAD feed program had a lower mean egg production than the hens fed on the ATD program. There were significant differences on plasma corticosterone concentrations between the feeding days (24 or 48 h after feeding) in both feed programs. There was a shift in the behavior of the birds with significant differences in the feeding, foraging, and comfort behaviors between the feeding programs on the same feed day. Overall, feeding the ATD females soybean hulls on the off feed day improved the BW uniformity and egg production, but further research will be needed to determine potential differences in nutrient utilization or behavior of the pullets that positively impacted this flock performance.

True nutrient and amino acid digestibility of dog foods made with human-grade ingredients using the precision-fed cecectomized rooster assay.

For a pet diet to be labeled as human-grade, every ingredient and the finished food must be stored, handled, processed, and transported according to the current good manufacturing practices for human edible foods. Human-grade dog foods are now available and increasing in popularity, but little research has been conducted to test the digestibility of these foods. For this reason, the objective of this experiment was to determine the true nutrient and amino acid (AA) digestibilities of dog foods formulated with human-grade ingredients using the precision-fed cecectomized rooster assay. Six commercial dog foods were tested, including the Beef & Russet Potato (BRP), Chicken & White Rice (CWR), Fish & Sweet Potato (FSP), Lamb & Brown Rice (LBR), Turkey & Whole Wheat Macaroni (TWM), and Venison & Squash (VSR) formulas provided by Just Food For Dogs LLC (Irvine, CA). Before analysis, all foods were lyophilized and ground. A precision-fed rooster assay using cecectomized roosters was conducted to determine the true nutrient digestibility and standardized AA digestibilities of the foods tested. Conventional roosters were used to determine the nitrogen-corrected true metabolizable energy (TMEn) of the foods. All animal procedures were approved by the University of Illinois Institutional Animal Care and Use Committee prior to experimentation. The substrates and rooster excreta were analyzed for macronutrient and AA composition. All data were analyzed using the Mixed Models procedure of SAS (version 9.4; SAS Institute, Cary, NC). In general, all foods tested were highly digestible. Dry matter digestibility was similar among CWR, LBR, and TWR foods, and greater (P < 0.0001) than that of FSP and VSR foods. Organic matter digestibility was highest (P = 0.0002) for CWR and lowest (P = 0.0002) for VSR. For the majority of indispensable AA, digestibilities were greater than 85%, with some being greater than 90%. TMEn was higher (P < 0.0001) for BRP than the other foods, which were similar to one another. Also, TMEn values were much higher than what would be estimated by using modified Atwater factors and often above the predictive equations for metabolizable energy (ME) recommended by the National Research Council or by using Atwater factors. Although statistical differences were observed among foods, they all performed well and the foods tested had very high AA digestibilities. Additionally, the TMEn data suggest that existing methods and equations for ME prediction underestimate the energy content of the foods tested.

Further evaluation of a slope-ratio precision-fed rooster assay and a limit-fed broiler chicken growth assay for relative metabolizable energy and relative bioavailable energy values of fats and oils

Three slope-ratio precision-fed rooster assays were conducted wherein roosters were precision-fed 0, 5, 10, 15, or 20% (levels varied among experiments) refined soy oil, refined corn oil (RCO), poultry fat, crude soy oil, crude corn oil, palm oil, vegetable blend acid oil 1 and 2, soy acid oil, tallow, or choice white grease as part of a ground corn diet. Multiple regression slope-ratio analysis of nitrogen-corrected true metabolizable energy regressed on dietary fat level was used to estimate relative metabolizable energy (RME) values. The RME values were calculated as the regression coefficient of the test lipid divided by the regression coefficient of the reference refined soy oil or RCO (set at 100%). The results of the rooster experiments indicated that only the RME values of palm oil 1 (83%) and tallow (74%) were significantly lower (P < 0.05) than that of refined soy oil or RCO. It was observed that the differences among fat sources were often greater at the higher inclusion levels of 15 and 20%. In addition to the slope-ratio precision-fed rooster assays, a limit-fed broiler chicken growth assay was conducted. The broilers were limit-fed to 70% of their expected daily intake from 11 to 20 d of age, and four lipid sources (RCO, palm oil 2, choice white grease, and vegetable blend acid oil 2) were tested at 0, 5, and 10% inclusion levels. Multiple regression slope-ratio analysis of body weight gain regressed on dietary fat intake indicated that the relative bioavailability values (RBV) of palm oil 2 (80%) and choice white grease (85%) were significantly lower than the 100% for RCO (P < 0.05), whereas the RBV of the vegetable blend acid oil 2 (93%) was not significantly different from 100%. In general, both the precision-fed rooster assay and the limit-fed broiler chicken assay were able to detect differences in RME or RBV among lipids; however, using higher inclusion rates of 15 or 20% of the lipids may increase sensitivity of the rooster assay.

Chemical composition, true nutrient digestibility, and true metabolizable energy of chicken-based ingredients differing by processing method using the precision-fed cecectomized rooster assay1

Chicken-based ingredients are commonly used in pet food products, but vary greatly in nutrient composition and processing conditions that may affect their protein quality and digestibility. Testing the quality of protein sources undergoing different processing conditions provides important information to pet food producers. The objective of this study was to determine the chemical composition, nutrient digestibility, protein, and AA digestibility scores, and nitrogen-corrected true metabolizable energy (TMEn) of chicken-based ingredients that had undergone different processing conditions (i.e., chicken meal, raw chicken, retorted chicken, and steamed chicken) using the precision-fed cecectomized rooster assay. True nutrient digestibility was variable among the protein sources (60% to 76% of DM, 66% to 81% of OM, 83% to 90% of AHF, 50% to 95% of AA and 73% to 85% of TMEn/GE). In general, the chicken meal had a lower (P < 0.05) nutrient digestibility than other ingredients tested, including DM, OM, and most indispensable and dispensable AA, with most having a true digestibility between 75% and 85%. The steamed chicken had the highest indispensable AA digestibilities, with all having a true digestibility greater than 88% and most being over 90%. TMEn value and digestible indispensable AA scores (DIAAS)-like values were higher (P < 0.0001) in the less processed chicken-based ingredients in comparison to chicken meal. Although animal proteins are often considered to be complete proteins, DIAAS-like values <100% suggest that ingredients like chicken meal may not provide all indispensable AA when included at levels to the meet minimal crude protein recommendation. Although raw protein sources are often touted as being the most digestible and of the highest quality, the steamed chicken had the highest (P < 0.0001) DIAAS-like values in this study. This study demonstrates the considerable variability that exists, not only in the chemical composition but also in the true nutrient digestibility among chicken-based ingredients undergoing different processing conditions. These data justify more in vivo testing and the use of DIAAS-like values that consider AA profile, in vivo digestibility, and species-specific recommendations, to evaluate protein-based ingredients intended for use in dog and cat foods.

Effects of dietary β-mannanase supplementation on the additivity of true metabolizable energy values for broiler diets.

ObjectiveThis experiment was conducted to determine the effects of dietary β-mannanase on the additivity of true metabolizable energy (TME) and nitrogen-corrected true metabolizable energy (TMEn) for broiler diets.MethodsA total of 144 21-day-old broilers were randomly allotted to 12 dietary treatments with 6 replicates. Five treatments consisted of 5 ingredients of corn, wheat, soybean meal, corn distillers dried grains with solubles, or corn gluten meal. One mixed diet containing 200 g/kg of those 5 ingredients also was prepared. Additional 6 treatments were prepared by mixing 0.5 g/kg dietary β-mannanase with those 5 ingredients and the mixed diet. Based on a precision-fed chicken assay, TME and TMEn values for 5 ingredients and the mixed diet as affected by dietary β-mannanase were determined.ResultsResults indicated that when β-mannanase was not added to the diet, measured TME and TMEn values for the diet did not differ from the predicted values for the diet, which validated the additivity. However, for the diet containing β-mannanase, measured TMEn value was greater (p<0.05) than predicted TMEn value, indicating that the additivity was not validated.ConclusionIn conclusion, the additivity of energy values for the mixed diet may not be guaranteed if the diet contains β-mannanase.

&lt;b&gt;Dry matter digestibility and metabolizable energy of crude glycerines originated from palm oil using fed rooster assay

A study was conducted to determine the dry matter digestibility, gross energy (GE), the nitrogen-corrected apparent metabolizable energy (AMEn), and the nitrogen-corrected true metabolizable energy (TMEn) of two crude glycerine from two different sources. The first crude glycerine (CG1) was from a large scale biodiesel producer with high content of glycerol (89.49%) and low content of crude fat (1.73%), meanwhile the second crude glycerine (CG2) was from a medium scale biodiesel producer with lower content of glycerol than CG1 (38.36%) and high content of crude fat (23.63%). Fed rooster assay based on Sibbald (1976) was used in the experiment. The experimental feed consisted of ground corn and three levels of crude glycerine (0, 10, and 20%). Twenty four Hisex brown roosters were housed in metabolic cages. Roosters were force fed with 30 g experimental feed, after 24 hours of fasting. Excreta collection was performed for two days while the roosters were fasting again. The content values of GE, AMEn, and TMEn of CG1 were 4065.18, 2926.59, and 3068.73 kcal kg -1 and for CG2 were 5928.09, 4010.11, and 4054.52 kcal kg, respectively.

Using locally produced millet as a feed ingredient for poultry production in Sub-Saharan Africa

Using locally produced feedstuffs for poultry production in developing countries can greatly lower production costs. Pearl millet is a drought-resistant plant that produces a nutritious grain. Its cultivation in Mali spans thousands of years, but the suitability of the millet grain currently produced in Mali for poultry production is unknown. Therefore, the nutrient composition of 7 different, widely available varieties of pearl millet grown in Mali was assessed before completing experiments in which laying hens or broilers were fed diets containing 0, 14, 28, or 43% whole pearl millet. The 7 varieties of pearl millet grown in different regions of Mali all had protein concentrations that were better than corn and had apparent digestible amino acid coefficients similar to corn. The nitrogen-corrected true metabolizable energy values ranged from 3,395 to 3,738 Kcal/kg on an as-is basis. Egg production and egg weight did not differ between the hens fed the different levels of millet through out a 16-wk experiment. Broilers fed the highest level of pearl millet from 1 to 42 d of age gained less (3.088 versus 2.949 kg) body weight than those fed the control diet. However, body weight gains did not differ between the broilers fed the control diet and the diets containing 14 or 28% whole millet. The results indicate that Malian-grown pearl millet would be an effective feed ingredient for poultry production and that this small seed could be added in whole form into laying hen and broiler diets.

Determination of True Metabolizable Energy Content of Bobwhite Foods

True metabolizable energy (TME) and nitrogen-corrected true metabolizable energy (TMEn) bioassays were used to determine available energy content of several northern bobwhite (Colinus virginianus) foods. A proximate analysis and trypsin inhibitor (TI) activity were also determined for each food. Corn (Zea mays) was found to contain the highest amount ofTMEn (4.37 kcal/g dry matter) compared with Fayette soybeans (Glycine max; 3.93 kcal/g), Korean lespedeza (Kummerowia stipuki.ceae; 3.73 kcal/g), Marion lespedeza (K. striata; 3.71 kcal/g), tick-trefoil (Desmodium spp.; 3.51 kcal/g), and wild trailing (WI') soybeans (3.24 kcal/g). The higher TMEn value of corn was attributed to its high digestible carbohydrate content and lack of appreciable TI activity.

Suitability of Soybean Meal from Insect-Resistant Soybeans for Broiler Chickens.

Benning(M) and Benning(MGH) are near-isogenic lines (NILs) of the soybean cultivar Benning, which contain insect-resistance quantitative trait loci (QTLs) from the soybean accession PI 229358. Benning(M) contains QTL-M, which confers antibiosis and antixenosis. In addition to QTL-M, Benning(MGH) contains QTL-G, which confers antibiosis, and QTL-H, which confers antixenosis. Soybean meal was produced from Benning and the NILs. Nutritional composition, digestible amino acid content, and nitrogen-corrected true metabolizable energy (TMEN) were equivalent among soybean meals. A 21-day broiler feeding trial was carried out to determine if the QTLs affect soybean meal quality. Weight gain and feed-to-gain ratio were evaluated. No biologically significant differences were detected for broilers fed Benning, Benning(M), and Benning(MGH). This demonstrates that soybean meal produced from the insect-resistant NILs is equivalent to soybean meal produced from their non-insect-resistant parent cultivar for broiler weight gain.

Nutritional properties of dried salmon silage for broiler feeding.

The aim of this study was to evaluate the chemical composition, energy and amino acid profile of dried salmon silage (DSS) for broilers. The DSS was obtained by acid digestion of salmon mortalities and subsequently co-dried with wheat bran in a 70:30 ratio (70 parts silage and 30 parts wheat bran). Samples of DSS were evaluated for chemical composition, gross energy, nitrogen-corrected true metabolizable energy (TMEn ), mineral content, total and digestible amino acids for broilers, and amino acid score. The chemical composition of DSS was (mean ± SD): moisture (12.3 ± 0.8%), crude protein (44.0 ± 1.1%), ether extract (5.0 ± 2.4%), crude fiber (3.3 ± 0.4%) and ash (9.4 ± 0.6%). The gross energy and TMEn for broilers were 4 069 kcal/kg and 2 613 kcal/kg, respectively. The DSS mineral composition showed a high content of calcium (1.01%) and phosphorus (1.08%). The DSS had high levels of digestible methionine (0.74%), lysine (2.27%), and threonine (1.16%), and did not present limiting amino acids for broilers. Nutritional composition of DSS showed high protein content with an amino acid profile considered to be suitable as a protein source for broiler feeding.

Nitrogen-corrected True Metabolizable Energy and Amino Acid Digestibility of Chinese Corn Distillers Dried Grains with Solubles in Adult Cecectomized Roosters.

This study was conducted to evaluate chemical composition, nitrogen-corrected true metabolizable energy (TMEn) and true amino acids digestibility of corn distillers dried grains with solubles (DDGS) produced in China. Twenty five sources of corn DDGS was collected from 8 provinces of China. A precision-fed rooster assay was used to determine TMEn and amino acids digestibility with 35 adult cecectomized roosters, in which each DDGS sample was tube fed (30 g). The average content of ash, crude protein, total amino acid, ether extract, crude fiber and neutral detergent fiber were 4.81, 27.91, 22.51, 15.22, 6.35 and 37.58%, respectively. TMEn of DDGS ranged from 1,779 to 3,071 kcal/kg and averaged 2,517 kcal/kg. Coefficient of variation for non-amino acid crude protein, ether extract, crude fiber and TMEn were 55.0, 15.7, 15.9 and 17.1%, respectively. The average true amino acid digestibility was 77.32%. Stepwise regression analysis obtained the following equation: TMEn, kcal/kg = −2,995.6+0.88×gross energy+49.63×a* (BIC = 248.8; RMSE = 190.8; p<0.01). Removing gross energy from the model obtained the following equation: TMEn, kcal/kg = 57.88×ether extracts+87.62×a* (BIC = 254.3, RMSE = 223.5; p<0.01). No correlation was found between color scores and lysine true digestibility (p>0.05). These results suggest that corn DDGS produced in China has a large variation in chemical composition, and gross energy and a* value can be used to generate TMEn predict equation.

Prediction of digestible amino acid and true metabolizable energy contents of sorghum grain from total essential amino acids

SUMMARYAccurate information on metabolizable energy and true digestible amino acid (TDAA) content of sorghum grain is important in order to formulate sorghum-based poultry diets accurately. Estimates of ingredient nutritional values using bioassay methods require live birds and special facilities, which are time-consuming and costly. Accordingly, prediction by mathematical models would be of some considerable benefit. Sixty-eight samples of sorghum grain, representing 32 different varieties, were used to test the correlation between TDAA and nitrogen-corrected true metabolizable energy (TMEn) with total essential amino acids. Two methods of multiple linear regressions (MLR) and artificial neural network (ANN) models were used to find the relationship between total amino acids (model inputs) with TDAA and TMEn contents (model outputs) in sorghum grain. The fitness of the models was tested usingR2, mean square (MS) error and bias. There is a strong relationship between total amino acid concentration with both TDAA and TMEn content in sorghum grain. The TDAA and TMEn values were more accurately estimated by ANN model compared to values obtained from the MLR model. TheR2values corresponding to testing and training of the ANN model showed a higher accuracy of prediction than the equation constructed by MLR method. Based on the experimental evidence, it is concluded that the TDAA and TMEn values in sorghum grain can be predicted from total essential amino acids using ANN models. Consequently, this method provides an opportunity to reduce the risk of formulating an unbalanced TDAA diet for poultry.