Autoclaving time-related reduction in amino acid digestibility of poultry meal in broiler chickens and growing pigs.

Poultry meal, a rendered byproduct of poultry slaughter, is a valuable protein source in swine and poultry diets because of its highly digestible protein content and balanced amino acid (AA) profile. Rendering of poultry meal may reduce its AA digestibility because of heat damage to the byproduct. The effect of heat damage on AA digestibility of poultry meal may be different between broiler chickens and growing pigs. For this reason, the objective of this study was to determine the effect of autoclaving time on standardized ileal digestibility (SID) of AA in poultry meal fed to broiler chickens and growing pigs. Poultry meal from the same batch was autoclaved at 134 °C for 0, 30, 60, 90, 120, 150, or 180 min to produce seven heat-treated samples. Eight experimental diets were formulated. Poultry meal served as the sole source of nitrogen in seven diets that each contained one of the heat-treated byproducts and a nitrogen-free diet was formulated to assess basal ileal endogenous losses of AA. In experiment 1, 656 male broiler chickens (initial body weight = 719 ±â€…97 g) at day 18 post hatching were assigned to the eight diets in a randomized complete block design with body weight as a blocking factor. On day 23, birds were euthanized by CO2 asphyxiation and dissected for the collection of ileal digesta. In experiment 2, 16 barrows (initial body weight = 23.3 ±â€…0.7 kg) were surgically fitted with T-cannulas at the distal ileum and allotted to a duplicate 8 × 4 incomplete Latin square design with the eight diets and four periods. Each experimental period consisted of 5-day adaptation and 2-day ileal digesta collection periods. Data for experiments 1 and 2 were pooled and analyzed as a 2 × 7 factorial treatment arrangement with the effects of species (i.e., pigs and broiler chickens) and autoclaving time (i.e., 0 to 180 min) as the two factors. Increasing autoclaving time decreased SID of nitrogen and all AA in both species, but the decrease in SID values except for leucine was greater (interaction, P < 0.05) or tended to be greater in pigs compared with broiler chickens. Given the species differences in AA utilization response to the severity of heat damage, target species should be considered when using SID of AA values of poultry meal in diet formulation.

Poultry meal, a rendered byproduct of poultry slaughter, is a valuable protein source in swine and poultry diets. Rendering is required during the processing of poultry meal to inactivate potential harmful bacteria and to reduce moisture content in the raw byproduct. However, rendering can induce heat damage to poultry meal, which may reduce amino acid (AA) digestibility. To mimic heat damage to poultry meal, the byproduct was autoclaved at 134 °C for 0, 30, 60, 90, 120, 150, or 180 min in the current study. These seven heat-treated poultry meal samples were then fed to broiler chickens and growing pigs. AA digestibility in poultry meal decreased with increasing autoclaving time, but the decrease in digestibility of most AAs by autoclaving was larger in growing pigs compared with broiler chickens.

Phosphorus equivalency of exogenous phytase relative to phosphorus in monosodium phosphate in broiler chickens.

The objective of this study was to estimate phosphorus (P) equivalency of exogenous phytase relative to P from monosodium phosphate (MSP) in broiler chickens. To attain this objective, the impact of dietary MSP or exogenous phytase on growth performance, ileal digestibility of P, and bone characteristics in broiler chickens was assessed. Six experimental diets consisting of a P-deficient basal diet based on corn and soybean meal, basal diet plus 0.9 or 1.8 g/kg of inorganic P from MSP, and basal diet plus 500, 1,000, or 2,000 FYT/kg of exogenous phytase. Calcium to P ratio in all diets was maintained at 1.5:1. A total of 576 male broiler chickens (Cobb 500; initial BW = 190 ± 17 g) on d 8 post hatching were allotted to the 6 dietary treatments in a randomized complete block design using BW as a blocking factor. Each dietary treatment contained 8 replicate cages with 12 birds per cage. On d 11 post hatching, 7 birds from each cage were euthanized by CO2 asphyxiation and dissected for the collection of ileal digesta. On d 18, ileal digesta were also collected from the remaining 5 birds in each cage. The left femur and tibia were collected from the bird with the median BW on d 11 and 18 from each cage, and analyzed for bone breaking strength and bone ash. Weight gain and gain-to-feed ratio linearly or quadratically increased (P < 0.05) in every period as the inclusion rate of MSP or phytase increased. Ileal digestibility of P linearly increased (P < 0.05) on d 11 with increasing MSP, but there was no significant effect on d 18. Increasing phytase concentration linearly increased (P < 0.05) ileal digestibility of P on d 11 and 18. Increasing dietary MSP or phytase linearly increased ileal digestible P concentration in diets (P < 0.05). Bone breaking strength and bone ash linearly or quadratically increased (P < 0.05) with increasing inclusion rate of MSP or phytase on d 11 and 18. The equivalency of 1,000 FYT/kg of exogenous phytase based on dietary ileal digestible P concentration was 1.5 and 1.2 g/kg of inorganic P in diets on d 11 and 18, respectively. The current results showed that the supplementation of MSP or exogenous phytase can increase growth performance, ileal P digestibility, bone breaking strength, and bone ash in young broiler chickens.

Impact of ileal indigestible protein on fecal nitrogen excretion and fecal microbiota may be greater compared with total protein concentration of diets in growing pigs.

In the current study, we hypothesized that an increase in dietary ileal indigestible protein concentration induces an increase in hindgut nitrogen utilization and nitrogen excretion and a shift in fecal microbiota in growing pigs, when compared to pigs given a high total protein diet. Three diets were prepared: 1) standard protein diet based on corn and soybean meal, 2) high-indigestible protein diet in which autoclaved, low-digestible soybean meal replaced soybean meal in the first diet, and 3) high protein diet where the inclusion rate of soybean meal was greater than that of the other diets. The 3 diets were fed to 18 barrows that were fitted with T-cannula at the ileo-cecal junction (initial body weight = 63.4 ±â€…8.0 kg) in a randomized complete block design with body weight as a blocking factor. Pigs were individually housed in pens and the experiment lasted for 23 d. On days 7 and 21, fecal samples were collected by rectal massage for microbiota analysis. Grab samples of feces were collected on days 20 and 21, and ileal digesta were collected on days 22 and 23 for the determination of energy and nitrogen utilization. Lower apparent ileal digestibility of nitrogen in the high-indigestible protein diet containing autoclaved soybean meal resulted in greater ileal indigestible nitrogen concentration (P < 0.05). Apparent total tract digestibility of nitrogen was lower (P < 0.05), and correspondingly nitrogen concentration and daily fecal nitrogen output were greater (P < 0.05) in the high-indigestible protein diet compared with the other diets. Apparent post-ileal digestibility and hindgut disappearance of nitrogen and gross energy were the greatest (P < 0.05) in the high protein diet, whereas a statistical difference was not observed in those variables between the standard protein diet and the high-indigestible protein diet. Beta diversity metrics of feces in the high-indigestible protein diet on day 21 were different (q < 0.05) from those in the other two diets, which indicates a shift in microbial communities. According to the results of the DESeq2, the direction of microbiota shift induced by the high-indigestible protein diet may have reduced fiber utilization in the hindgut. In conclusion, an increase in dietary ileal indigestible protein concentration increased fecal nitrogen excretion and shifted fecal microbial communities but did not increase nitrogen utilization in the hindgut.

Dietary protein concentration has been gradually reduced because reductions in protein concentration in swine diets are known to be beneficial in terms of feed costs, nitrogen excretion, and intestinal microbiota. However, ileal indigestible protein concentration may be more influential in those variables of pigs compared with total protein concentration in diets because ileal indigestible protein considers both protein concentration and digestibility of diets. In the current study, three diets were prepared: 1) corn-soybean meal diet, 2) high-indigestible protein diet replacing soybean meal in the first diet with autoclaved soybean meal, and 3) high protein diet where the inclusion rate of soybean meal was greater than that of the other diets. The experimental diets were fed to cannulated pigs and ileal digesta and fecal samples were collected. Fecal nitrogen output was greater in pigs fed the high-indigestible protein diet. Fecal microbiota was shifted by the high-indigestible protein diet, and this shift may not be beneficial. In conclusion, the impact of changes in ileal indigestible protein on fecal nitrogen excretion and fecal microbiota may be greater compared to changes in total protein concentration of diets in growing pigs.

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).

Poultry meal is a rendered product that consists of clean flesh and skin-derived from the parts of whole carcasses of slaughtered poultry. Because poultry meal has a highly digestible protein concentration and optimal amino acid profile, it is widely used in swine and poultry diets. During the rendering process, poultry meal is heated, which may affect energy utilization. In the current study, poultry meal was autoclaved at 134 °C for 0, 30, 60, 90, 120, 150, or 180 min to mimic heating of poultry meal. These seven poultry meal samples were fed to growing pigs and broiler chickens. Reduction in energy utilization with autoclaving time of poultry meal was greater in growing pigs compared with broiler chickens. However, despite a larger decrease in energy utilization in poultry meal by autoclaving in growing pigs, metabolizable energy values were still greater in growing pigs compared with broiler chickens.

Research Note: Estimation of individual feed intake of broiler chickens in group-housing systems.

In most experiments, broiler chickens are group-housed and share the same feeder in a given cage or pen. Correction of feed intake in a given pen is sometimes required in the event of mortality or identification of birds within a pen as outliers. For this reason, an accurate estimation of individual feed intake (IFI) is important. The objective of this study was to compare 3 different methods of estimating the IFI of broiler chickens in group-housing systems. The methods utilized in the current study consisted of an averaging method, a ratio method, and a partitioning method. The assumption of the averaging method is that birds in a cage consume an equal amount of feed, whereas feed intake of a given bird is proportional to its BW gain in the ratio method. The partitioning method bifurcates IFI into IFI for maintenance and growth. To validate these methods, 32 male broiler chickens (initial BW = 161 ± 19 g) at d 7 post hatching were individually housed in cages. Birds were fed a corn-soybean meal-based diet for 28 d, and body weight and feed disappearance were recorded on d 14, 21, 28, and 35. Excreta were collected over the last 3 d of each week. As age of broiler chickens increased, body weight gain, feed intake, and dietary metabolizable energy both linearly and quadratically increased, whereas gain-to-feed ratio both linearly and quadratically decreased (P < 0.05). The partitioning method estimated IFI more accurately compared with the averaging method and the ratio method (P < 0.05). The current result implies that the partitioning method would accurately estimate IFI of broiler chickens in group-housing systems.

Additivity of digestible energy and nutrient concentrations in hatchery byproducts fed to nursery pigs.

OBJECTIVE: The objective was to test additivity of digestible energy and nutrient concentrations in the hatchery byproduct mixture fed to nursery pigs. METHODS: In the previous studies, energy, phosphorus, calcium, and amino acid digestibility of infertile eggs, unhatched eggs, culled chicks, and a mixture of 3 hatchery byproduct ingredients was determined in nursery pigs (initial body weight = 9.4 to 14.2 kg). An additivity test was conducted using these determined values. RESULTS: No difference was observed between determined and predicted metabolizable energy values in the mixture (3,998 and 3,990 kcal/kg as-is basis, respectively). Measured standardized total tract digestible phosphorus in the mixture was less than the predicted value (4.5 vs 5.3 g/kg as-is basis, respectively; p<0.05). Measured standardized total tract digestible calcium in the mixture was greater compared with the predicted value (40.0 vs 31.7 g/kg as-is basis, respectively; p<0.05). Measured standardized ileal digestible tryptophan in the mixture was greater than the predicted value (3.7 vs 3.1 g/kg as-is basis, respectively; p<0.05) whereas other amino acid values were additive. CONCLUSION: Energy and most of amino acid concentrations in hatchery byproducts are additive in the mixture fed to nursery pigs.

Equations to Predict Growth Performance Changes by Dietary Deoxynivalenol in Pigs.

The objectives of the present work were to assess the accuracy of previously published equations for predicting effects of deoxynivalenol (DON) on the growth performance changes of pigs and to update equations based on recently published data. A total of 59 data were employed for the validation of previously published equations. These data were used to update the equations. The REG and CORR procedures of SAS were used. In the present validation test, a linear bias was significant (p < 0.05), indicating that prediction errors were not consistent across the data ranges. The intercept for ΔFI (-7.75 ± 1.19, p < 0.01) representing a mean bias was less than 0, indicating that the predicted mean of ΔFI was greater than the measured mean of ΔFI. Dietary DON concentrations had negative correlations with ΔWG (r = -0.79; p < 0.01) and ΔFI (r = -0.71; p < 0.01). Updated prediction equations were: ΔWG = -5.93 × DON with r2 = 0.77 and ΔFI = -4.42 × DON with r2 = 0.68. In conclusion, the novel equations developed in this study might accurately predict effects of dietary DON on the performance changes of pigs.

Energy values and protein digestibility of soybean milk by-product in pigs based on in vitro assays / Valores energéticos y digestibilidad proteica del subproducto de la leche de soja en cerdos con base en ensayos in vitro / Valores energéticos e digestibilidade protéica do subproduto do leite de soja em suínos com base em ensaios in vitro

Abstract Background: Soybean milk by-product (SMBP) is a potential alternative feed ingredient in swine diets due to its high protein content. However, information on energy and nutritional values of SMBP used as swine feed ingredient is limited. Objective: To estimate energy values and protein digestibility of SMBP in pigs based on in vitro assays. Methods: Four SMBP samples were obtained from 3 soybean milk-producing facilities. In vitro total tract disappearance (IVTTD) and in vitro ileal disappearance (IVID) of dry matter (DM) in the SMBP samples were determined. In vitro ileal disappearance of crude protein was determined by analyzing crude protein content in undigested residues after determining IVID of DM. Digestible and metabolizable energy of SMBP were estimated using gross energy, IVTTD of DM, and prediction equations. Results: Sample 4 had greater IVTTD of DM than that of sample 3 (97.7 vs. 94.4%, p<0.05), whereas IVID of DM in sample 4 was lower compared with sample 1 (53.5 vs. 65.0%, p<0.05). In vitro ileal disappearance of crude protein in sample 2 was greater than that in sample 1 and 3 (92.6 vs. 90.6 and 90.1%; p<0.05). The estimated metabolizable energy of SMBP ranged from 4,311 to 4,619 kcal/kg as-is basis and the value of sample 3 was the least (p<0.05) among SMBP samples. Conclusion: Energy values and protein digestibility should be determined before using SMBP in swine diets.

Resumen Antecedentes: El subproducto de la leche de soja (SMBP) es un ingrediente alimenticio alternativo con uso potencial en dietas porcinas dado su alto contenido de proteína. Sin embargo, la información sobre sus valores energéticos y nutricionales para alimentación de cerdos es muy limitada. Objetivo: Estimar los valores de energía y la digestibilidad de la proteína del SMBP en cerdos con base en ensayos in vitro. Métodos: Se obtuvieron cuatro muestras de SMBP de tres empresas productoras de leche de soja. Se determinaron la desaparición de tracto total in vitro (IVTTD) y la desaparición ileal in vitro (IVID) de la materia seca (DM) en las muestras de SMBP. La desaparición ileal in vitro de proteína cruda se determinó analizando el contenido de proteína cruda en residuos no digeridos después de determinar la IVID de la DM. La energía digestible y metabolizable de SMBP se estimó utilizando la energía bruta, IVTTD de la DM y ecuaciones de predicción. Resultados: La muestra 4 tuvo una mayor IVTTD de la DM que la muestra 3 (97,7 vs. 94,4%, p<0,05), mientras que la IVID de la DM en la muestra 4 fue menor en comparación con la muestra 1 (53,5 vs. 65,0%, p<0,05). La desaparición ileal in vitro de la proteína cruda en la muestra 2 fue mayor que la de las muestras 1 y 3 (92,6 vs. 90,6 y 90,1%; p<0,05). La energía metabolizable estimada de SMBP varió de 4.311 a 4.619 kcal/kg (en base húmeda) y el valor de la muestra 3 fue el menor (p<0.05) entre las muestras de SMBP. Conclusión: Los valores de energía y la digestibilidad de la proteína deben determinarse antes de usar el SMBP en dietas porcinas.

Resumo Antecedentes: O subproduto do leite de soja (SMBP) é um potencial ingrediente alternativo na dieta de suínos, considerando seu alto teor de proteínas. No entanto, as informações sobre os valores energéticos e nutricionais do SMBP usado como ingrediente alimentar para suínos são limitadas. Objetivo: Estimar valores energéticos e digestibilidade protéica do SMBP em suínos com base em ensaios in vitro. Métodos: Foram obtidas quatro amostras de SMBP de três instalações produtores de leite de soja. Foram determinados o desaparecimento total do trato in vitro (IVTTD) e o desaparecimento ileal in vitro (IVID) da matéria seca (DM) nas amostras de SMBP. O desaparecimento ileal in vitro da proteína bruta foi determinado pela análise do conteúdo de proteína bruta em resíduos não digeridos após a determinação da IVID do DM. A energia digerível e metabolizável do SMBP foi estimada usando energia bruta, IVTTD do DM e equações de predição. Resultados: a amostra 4 apresentou maior IVTTD de DM do que a amostra 3 (97,7 vs. 94,4%, p<0,05) enquanto a IVID do DM na amostra 4 foi menor em comparação com a amostra 1 (53,5 vs. 65,0%, p<0,05). O desaparecimento ileal in vitro da proteína bruta na amostra 2 foi superior ao da amostra 1 e 3 (92,6 vs. 90,6 e 90,1%; p<0,05). A energia metabolizável estimada do SMBP variou de 4.311 a 4.619 kcal/kg no estado em que se encontra e o valor da amostra 3 foi o menor (p<0,05) entre as amostras do SMBP. Conclusão: os valores energéticos e a digestibilidade das proteínas devem ser determinados antes do uso do SMBP nas dietas suínas.

Prediction equations for digestible and metabolizable energy concentrations in feed ingredients and diets for pigs based on chemical composition.

OBJECTIVE: The objectives were to develop prediction equations for digestible energy (DE) and metabolizable energy (ME) of feed ingredients and diets for pigs based on chemical composition and to evaluate the accuracy of the equations using in vivo data. METHODS: A total of 734 data points from 81 experiments were employed to develop prediction equations for DE and ME in feed ingredients and diets. The CORR procedure of SAS was used to determine correlation coefficients between chemical components and energy concentrations and the REG procedure was used to generate prediction equations. Developed equations were tested for the accuracy according to the regression analysis using in vivo data. RESULTS: The DE and ME in feed ingredients and diets were most negatively correlated with acid detergent fiber or neutral detergent fiber (NDF; r = -0.46 to r = -0.67; p<0.05). Three prediction equations for feed ingredients reflected in vivo data well as follows: DE = 728+0.76×gross energy (GE)-25.18×NDF (R2 = 0.64); ME = 965+0.66×GE-24.62×NDF (R2 = 0.60); ME = 1,133+0.65×GE-29.05×ash-23.17×NDF (R2 = 0.67). CONCLUSION: In conclusion, the equations suggested in the current study would predict energy concentration in feed ingredients and diets.

Ileal Digestibility and Total Tract Retention of Phosphorus in Inorganic Phosphates Fed to Broiler Chickens Using the Direct Method.

The objective of this study was to determine and compare the phosphorus (P) utilization of inorganic phosphates fed to broiler chickens using the direct method. On day 15 of age, six hundred forty 15-day-old male Ross 308 broiler chickens (initial body weight = 399 ± 38 g) were assigned to five experimental diets with 16 birds per cage in a randomized complete block design. The experimental diets consisted of four semi-purified diets containing monocalcium phosphate, monodicalcium phosphate, dicalcium phosphate, and tricalcium phosphate as the sole P sources. Additionally, a P-free diet was prepared to measure basal endogenous P loss. Chromic oxide was added to the experimental diets as an indigestible index. Excreta were collected per cage on days 17 to 18 of age, and all birds were asphyxiated with carbon dioxide on day 19 of age for ileal digesta collection. The cage was an experimental unit, and the number of replications per each treatment was eight except for the tricalcium phosphate treatment (n = 4). There was no interaction observed between the P source and the collection site (ileal digestibility vs. total tract retention). Phosphorus utilization differed (p < 0.05) among inorganic phosphates and the ileal digestibility of P was greater (p < 0.05) than the total tract retention. In conclusion, the standardized ileal digestibility of P in inorganic phosphates ranged from 56.7% to 89.8% and ileal digestibility was greater than the total tract retention.

Additivity of Ileal Amino Acid Digestibility in Diets Containing Corn, Soybean Meal, and Corn Distillers Dried Grains with Solubles for Male Broilers.

The aim was to test additivity of apparent ileal digestibility (AID) and standardized ileal digestibility (SID) of amino acids (AAs) in mixed diets for Ross 308 broiler chickens. Two hundred and eighty-eight, 20-d-old male broiler chickens were assigned to one of six diets, with six birds per cage using a randomized complete block design. The diets consisted of a nitrogen-free diet, three diets containing corn, soybean meal (SBM), and corn distillers dried grains with solubles (CDDGS) as the sole source of nitrogen, respectively, and two mixed diets containing corn, SBM or CDDGS. Chromic oxide was added to the diets as an indigestible index. On day 24, birds were euthanized for ileal digesta collection. Relative proportion of the basal endogenous loss of AAs to total ileal outflow of AAs in corn was greater (p < 0.05) than that of SBM and CDDGS. For the corn-SBM and corn-SBM-CDDGS mixed diets, the AID of AAs differed (p < 0.05) from the predicted values. No difference was observed between the measured and predicted SID of AA. In conclusion, the SID of AAs is more additive in mixed diets containing corn, SBM, or CDDGS compared to AID values.

Effects of a Hatchery Byproduct Mixture on Growth Performance and Digestible Energy of Various Hatchery Byproduct Mixtures in Nursery Pigs.

The objectives were to determine effects of a hatchery byproduct mixture (HBM) on growth performance and to measure digestible energy concentrations in various HBM. In the growth performance experiment, 96 pigs (initial body weight = 9.6 ± 0.8 kg) were assigned to 4 dietary treatments in a randomized complete block design with 6 blocks. Each treatment consisted of 6 replicate pens with 4 pigs comprising 2 barrows and 2 gilts. Pigs were fed graded concentrations of HBM at 0%, 3.33%, 6.67%, and 10.00% for 14 days. In the energy digestibility experiment, 10 barrows (initial body weight = 11.5 ± 0.4 kg) were employed to determine digestible energy in HBM. A basal diet based on corn and soybean meal and 4 additional diets containing 25% of 4 different HBM were prepared. The marker-to-marker method was employed for total collection and the experimental design was a replicated 5 × 4 Latins square design. Growth performance was not compromised as the inclusion rate of HBM increased up to 10%. Digestible energy of HBM ranged from 2772 to 3887 kcal/kg as-is basis. In conclusion, HBM can be used in nursery pig diets and different energy values should be used for each HBM.

Neutral detergent fiber rather than other dietary fiber types as an independent variable increases the accuracy of prediction equation for digestible energy in feeds for growing pigs.

OBJECTIVE: The objectives were to investigate correlations between energy digestibility (digestible energy [DE]:gross energy [GE]) and various fiber types including crude fiber (CF), total dietary fiber (TDF), soluble dietary fiber (SDF), insoluble dietary fiber (IDF), neutral detergent fiber (NDF), and acid detergent fiber (ADF), and to develop prediction equations for estimating DE in feed ingredients and diets for growing pigs. METHODS: A total of 289 data with DE values and chemical composition of feeds from 39 studies were used to develop prediction equations for DE. The equations were validated using values provided by the National Research Council. RESULTS: The DE values in feed ingredients ranged from 2,011 to 4,590 kcal/kg dry matter (DM) and those in diets ranged from 2,801 to 4,203 kcal/kg DM. In feed ingredients, DE:GE was negatively correlated (p<0.001) with NDF (r = -0.84), IDF (r = -0.83), TDF (r = -0.82), ADF (r = -0.78), and CF (r = -0.72). A best-fitting model for DE (kcal/kg) in feed ingredients was: 1,356 + (0.704 × GE, kcal/kg) - (60.3 × ash, %) - (27.7 × NDF, %) with R2 = 0.80 and p<0.001. In diets, DE:GE was negatively correlated (p<0.01) with NDF (r = -0.72), IDF (r = -0.61), TDF (r = -0.52), CF (r = -0.45), and ADF (r = -0.34). A best-fitting model for DE (kcal/kg) in diets was: 1,551 + (0.606 × GE, kcal/kg) - (22.1 × ash, %) - (25.6 × NDF, %) with R2 = 0.62 and p<0.001. All variables are expressed as DM basis. The equation developed for DE in feed ingredients had greater accuracy than a published equation for DE. CONCLUSION: All fiber types are reasonably good independent variables for predicting DE of swine feeds. The best-fitting model for predicting DE of feeds employed neutral detergent fiber as an independent variable.

Energy Concentration and Phosphorus Digestibility in Hatchery Byproducts Fed to Nursery Pigs.

The objective was to measure energy concentrations and standardized total tract digestibility (STTD) of phosphorus (P) in hatchery byproducts. In Experiment 1, 20 nursery barrows were used to measure energy concentrations in hatchery byproducts. A basal diet based on corn and dried whey and four additional diets containing 25% of infertile eggs, unhatched eggs, culled chicks, or a mixture of the three hatchery byproducts were prepared. In Experiment 2, the STTD of P was measured using 20 nursery barrows. Four diets containing 25% of the same hatchery byproducts used in Experiment 1 as the sole source of P were prepared, and a P-free diet was prepared to measure basal endogenous losses of P. The marker-to-marker method was employed for total collection. Metabolizable energy in culled chicks was the greatest (4560 kcal/kg as-is basis; p < 0.05), whereas infertile eggs had the lowest value (2645 kcal/kg as-is basis; p < 0.05). The STTD of P in infertile eggs (81.7%) was greater than that in unhatched eggs, culled chicks, and the mixture (61.6, 53.9, and 47.4%, respectively; p < 0.05). In conclusion, culled chicks had the greatest metabolizable energy and infertile eggs had the greatest phosphorus digestibility among the test ingredients.