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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 ± 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 ± 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., (© The Author(s) 2024. Published by Oxford University Press on behalf of the American Society of Animal Science. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Canola products including full-fat canola seeds (FFCS), canola meal (CM), and canola expellers (CE) have been used in diets for both broiler chickens and pigs. However, their ability to utilize the AA in canola products might be different from each other. Therefore, this study was conducted to compare the apparent ileal digestibility (AID) and standardized ileal digestibility (SID) of CP and AA in broiler chickens and growing pigs fed FFCS, CM, and CE. Three diets were prepared to contain FFCS, CM, or CE as a sole source of nitrogen. A nitrogen-free diet was prepared. In Exp. 1, a total of 272 twenty-one-day-old male broiler chickens with an initial BW of 932 ± 80.6 g were assigned to diets in a randomized complete block design with BW as a blocking factor. After 5 d of feeding, birds were euthanized by sodium pentobarbital, and ileal digesta samples were collected from distal two-third of the ileum. In Exp. 2, 16 barrows were surgically fitted with T-cannulas at the distal ileum. After 8-d recovery period, pigs (initial BW = 18.9 ± 1.17 kg) were divided into 4 blocks based on BW and assigned to a quadruplicate 4 × 2 incomplete Latin Square design with 4 diets and 2 periods. Each period consisted of 5-d adaptation and 2-d ileal digesta collection periods. Data were analyzed as a 2 × 3 factorial treatment arrangement with effects of species (broiler chickens or pigs) and diets (FFCS, CM, or CE). There were interactions (P < 0.05) between species and experimental diets in the AID of all indispensable AA except for Lys. The AID of indispensable AA in FFCS for broiler chickens was greater (P < 0.05) than for pigs. Broiler chickens also had greater (P < 0.05) AID of Arg, His, Leu, Phe, and Val in CM compared with pigs; however, there were no differences in the AID of indispensable AA in CE between broiler chickens and pigs. The basal ileal endogenous losses of CP and AA, except Trp, in pigs were greater (P < 0.05) than in broiler chickens. There were also interactions (P < 0.05) between species and experimental diets in the SID of all indispensable AA except for Lys. Broiler chickens fed the diet containing FFCS had greater (P < 0.05) SID of indispensable AA compared with pigs fed the same diet; however, the SID of indispensable AA in CM or CE were not different between broiler chickens and pigs. In conclusion, differences in digestibility of AA in canola products were affected by nonruminant animal species.

This experiment was conducted to determine the ileal digestibility of CP and AA in casein by regression analysis and to investigate the effects of casein in experimental diets on the apparent ileal digestibility (AID) and standardized ileal digestibility (SID) of CP and AA in corn distillers' dried grains with solubles (DDGS) fed to pigs. Twenty barrows (initial BW = 50.5 ± 4.46 kg) surgically fitted with T-cannulas at the distal ileum were used. Eighteen pigs were assigned to a triplicate 6 × 3 incomplete Latin Square design with 6 diets and 3 periods. Two pigs were used as replacements. Three diets were prepared to contain 60, 100, or 140 g/kg casein to determine the ileal digestibility of CP and AA in casein by regression analysis, and 2 diets were prepared to contain either 480 g/kg DDGS or 308 g/kg DDGS and 60 g/kg casein. Casein and DDGS were the sources of nitrogen (N) in experimental diets. A N-free diet was prepared based on cornstarch and dextrose. Experimental periods consisted of 5 d of adaptation and 2 d of ileal digesta collection periods. The AID of CP and AA in casein linearly increased (P < 0.01) with increasing concentration of casein in the diets. The SID of indispensable AA in casein ranged from 94.7% (SEM = 1.16) for Ile in pigs fed the diet containing 60 g/kg casein to 103.3% (SEM = 2.21) for Arg in pigs fed the diet containing 100 g/kg casein. Except for Arg, pigs fed the diet containing DDGS and casein had greater (P < 0.001) SID of CP and indispensable AA than those fed the diet containing DDGS without casein. The ileal digestibility of indispensable AA in casein determined by regression analysis ranged from 96.8% (SE = 3.14) for Thr to 103.1% (SE = 4.40) for Arg. The AID and SID of CP and AA for DDGS in the diet containing casein were calculated by difference method using the ileal digestibility of CP and AA in casein determined by regression analysis. The AID of Lys for DDGS in the diet containing casein was greater (P = 0.035) than those without casein; however, the AID of CP and the other indispensable AA, except for Arg, Phe, and Trp, for DDGS in the diet containing casein was less (P < 0.05) than those without casein. The SID of Lys and Phe for DDGS in the diet containing casein was greater (P < 0.05) than those without casein. In conclusion, improved AA composition in semi-purified experimental diets may affect the SID of AA in low-quality protein ingredients.

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Poultry meal (PoMe), a rendered product of slaughtered poultry carcasses, is widely used in swine and poultry diets because of its highly digestible protein and balanced amino acid profile. Rendering may reduce amino acid digestibility of PoMe because rendering can induce heat damage to PoMe, and the effect of heat damage on amino acid digestibility in PoMe may be different between broiler chickens and growing pigs. For this reason, the objective of this study was to determine the effect of autoclaving on standardized ileal digestibility (SID) of amino acid in PoMe 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 for 7 samples. Eight experimental diets consisted of 7 diets containing each PoMe sample as a sole source of nitrogen and a nitrogen-free diet. In Exp. 1, 656 male broiler chickens (initial BW = 719 ± 97 g) at d 18 post hatching were assigned to the 8 diets in a randomized complete block design with BW as a blocking factor. On d 23, birds were euthanized by CO2 asphyxiation and dissected for the collection of ileal digesta. In Exp. 2, 16 barrows (initial BW = 23.3 ± 0.7 kg) surgically fitted with T-cannulas at the distal ileum were allotted to duplicate 8 × 4 incomplete Latin square design with the 8 diets and 4 periods. Each experimental period consisted of 5-d adaptation and 2-d ileal digesta collection periods. Data for Exp. 1 and 2 were pooled together 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). An Interaction between species and linear effect of autoclaving time was observed (P < 0.05) in SID of nitrogen, arginine, and threonine in PoMe. To be specific, the linear decrease in ileal digestibility of nitrogen and those AA with increasing autoclaving time was greater in pigs compared with broiler chickens. The SID of AA both linearly and quadratically decreased (P < 0.05) as autoclaving time increased. The SID of isoleucine, leucine, methionine, phenylalanine, and tryptophan in PoMe was greater (P < 0.05) in growing pigs compared with broiler chickens regardless of autoclaving time. In conclusion, increasing autoclaving time decreases SID of amino acids in PoMe, and SID values in some indispensable amino acids are greater in growing pigs compared with broiler chickens. [ABSTRACT FROM AUTHOR]

Two experiments were conducted to determine the influence of sources or concentrations of dietary fiber in nitrogen-free diets (NFD) on basal ileal endogenous losses (BEL) of amino acids (AA) and subsequent standardized ileal digestibility (SID) of AA in feed ingredients for pigs derived from such BEL. In Exp. 1, 20 pigs (initial body weight = 46.5 ± 2.97 kg) were assigned to five diets in a quadruplicate 5 × 2 incomplete Latin square design with two periods. Three NFD containing cellulose (insoluble and fermentable fiber), inulin (soluble and fermentable fiber), or carboxymethyl cellulose (CMC; soluble and non-fermentable fiber) at 40 g/kg plus two diets containing soybean meal (SBM) or wheat distillers' dried grains (WDDG) as the sole source of nitrogen were prepared. Pigs fed NFD containing CMC had greater (P < 0.05) BEL of AA, except for Arg and Pro, than those fed the other NFD. The SID of most AA in SBM and WDDG corrected by BEL of AA from NFD containing CMC were greater (P < 0.05) than those corrected by BEL of AA from the other NFD. Experiment 2 was conducted with 21 barrows (initial body weight = 34.1 ± 2.57 kg) assigned to seven diets in a triplicate 7 × 3 incomplete Latin square design with 3 periods. Seven diets consisted of three NFD containing 4, 8, or 12 g/kg cellulose and four diets containing corn, wheat, SBM, or canola meal as the sole source of nitrogen. There was no difference in the BEL of AA, except for Pro, among pigs fed NFD with increasing concentration of cellulose. The SID of AA in test ingredients were not affected by BEL of AA from NFD containing increasing concentration of cellulose. In conclusion, chemical characteristics of dietary fiber, but not concentration, affect the BEL of AA in pigs. [ABSTRACT FROM AUTHOR]