Apparent metabolisable energy and amino acid digestibility of microalgae Spirulina platensis as an ingredient in broiler chicken diets

ABSTRACT

1. This work investigates the apparent metabolisable energy (AME), its nitrogen-corrected form (AMEn) and amino acid (AA) digestibility coefficients of the microalgae Spirulina platensis as an ingredient in broiler chicken diets.

2. One group of birds was fed with a basal control diet (BD), and another was fed with a test diet composed of the BD with the addition of the microalgae at a proportion of 200 g/kg. AME and AMEn were assessed by total excreta collection and indigestibility analysis using acid-insoluble ash (AIA) as a marker.

3. The microalgae comprised 888.0 g/kg dry matter (DM), 18.42 MJ/kg gross energy, 514.7 g/kg crude protein, 9.9 g/kg ether extract, 10.6 g/kg crude fibre, 94.4 g/kg ash, 3.1 g/kg Ca and 11.0 g/kg P.

4. The values obtained for AME (13.48 MJ/kg DM) and AMEn (11.72 MJ/kg DM) were higher (p < 0.01) than those obtained using the AIA method (9.39–8.29 MJ/kg DM). The microalgae ileal digestibility coefficients were 0.80 ± 0.04 and 0.78 ± 0.04 for essential and non-essential AA, respectively.

5. Overall, the metabolisable energy content and digestibility of AA for S. platensis indicated that the microalgae are potentially an alternative nutrient source for broilers. The AIA method underestimated AME and AMEn in comparison to the total excreta collection method.     

猪脱酚棉籽蛋白能量及粗蛋白质消化率的比较评定

研究旨在评定猪对脱酚棉籽消化能和粗蛋白表观消化率,并比较脱酚棉籽蛋白(DCP)与豆粕(SBM)之间差异。选用体重(36.2±1.6)kg的杜×长×大三元杂交猪6头,采用套算法、双3×3拉丁方试验设计,试验日粮分别为脱酚棉籽蛋白日粮、豆粕日粮和基础日粮,每个拉丁方阶段包括5 d预饲期、5 d正式期,整个试验共30 d。结果表明,脱酚棉籽蛋白、豆粕消化能含量分别为12.41 MJ/kg、13.62 MJ/kg。脱酚棉籽蛋白、豆粕中粗蛋白表观消率化分别为73.35%、82.05%,表观可消化粗蛋白含量分别为37.92%、35.45%。脱酚棉籽蛋白是新型蛋白质原料,其消化能含量为豆粕的91.11%,粗蛋白表观消率化为豆粕的89.39%,可消化粗蛋白含量为豆粕的106.99%。脱酚棉籽蛋白在猪饲料中的应用具有广阔的前景。     

Additivity of values for apparent and standardized ileal digestibility of amino acids in mixed diets fed to growing pigs

The objective of this experiment was to determine whether the digestibility of CP and AA in a mixed diet fed to growing pigs is better predicted when based on standardized ileal digestibility coefficients (SID) or apparent ileal digestibility coefficients (AID). Eight growing pigs (initial BW = 92.1 +/- 3.19 kg) were surgically equipped with a T-cannula in the distal ileum and arranged in an 8 x 8 Latin square design with eight diets and eight periods. Three of the diets contained corn, soybean meal (SBM), or canola meal (CM) as the sole source of CP and AA. Four mixed diets also were formulated using corn and soybean meal (CS); corn and canola meal (CCM); soybean meal and canola meal (SCM); or corn, soybean meal, and canola meal (CSCM). A N-free diet was used to measure the basal ileal endogenous losses (IAAend) of CP and AA. Pigs were fed each of the eight diets during one 7-d period, and ileal digesta were collected during two 10-h periods on d 6 and 7. The AID values were calculated for CP and AA in all diets, except the N-free diet. By correcting the AID for IAAend, the SID for CP and AA in each of the seven protein-containing diets were calculated. As expected, the AID for CP and the majority of AA were greater in SBM than in corn and CM (P < 0.05); however, the SID for CP and most AA did not differ between corn and SBM. For the majority of the AA, SID were less (P < 0.05) in CM than in the other two ingredients. Using the AID and the SID that were measured for CP and AA in corn, SBM, and CM, the AID and the SID in the four mixed diets were predicted and compared with the measured values for these diets. For the three mixed diets containing corn, the measured AID for CP and most AA were greater (P < 0.05) than the predicted AID, but with a few exceptions, no differences between predicted and measured values for SID were observed. For the diet based on SCM, there were no differences between predicted and measured values regardless of the procedure used, except for the AID of Ser. The results of this experiment demonstrate that the digestibility coefficients for a mixed diet containing low-protein feed ingredients, such as corn, are more accurately predicted using SID than AID.     

Dried skim milk as a replacement for soybean meal in growing-finishing diets: effects on growth performance, apparent total-tract nitrogen digestibility, urinary and fecal nitrogen excretion, and carcass traits in pigs

Two trials were conducted to determine the replacement nutritive value of dried skim milk for growing-finishing pigs. In a three-phase feeding trial, 180 growing composite barrows (40.8 +/- 2.9 kg BW) were allotted to three dietary treatments. Each phase lasted 28 d. Treatment 1 comprised a basal corn-soybean meal diet supplemented with crystalline AA to contain true ileal digestible concentrations (as-fed basis) of 0.83, 0.66, and 0.52% Lys; 0.53, 0.45, and 0.40% Thr; and 0.51, 0.45, and 0.42% sulfur amino acids (SAA; Met + Cys) in Phases 1, 2, and 3, respectively. Treatments 2 and 3 were the basal diets with 5 and 10% (as-fed basis) dried skim milk added. The three diets at each phase were formulated to have the same quantities of DE, true ileal digestible Lys, Thr, Trp, SAA, Ca, and available P. Pigs were housed 10 per pen (six pens/treatment), allowed ad libitum access to feed, and slaughtered at 121.6 +/- 9.3 kg BW. No differences were detected between pigs fed the basal diet and the dried skim milk diets or between pigs fed the 5 and 10% dried skim milk diets, respectively, in 84-d ADG (P = 0.84 or P = 0.71), ADFI (P = 0.54 or P = 0.91), and G:F (P = 0.80 or P = 0.97), in hot carcass weight (P = 0.66 or P = 0.74), 45-min postmortem LM pH (P = 0.90 or P = 0.53), 10th-rib backfat thickness (P = 0.24 or P = 0.77), LM area (P = 0.13 or P = 0.63), weights of belly (P = 0.43 or P = 0.70), trimmed wholesale cuts (P = 0.18 to 0.85 or P = 0.06 to 0.53), and ham components (P = 0.25 to 0.98 or P = 0.32 to 0.63). In the N balance trial, four littermate pairs of finishing gilts (82.9 +/- 2.0 kg BW) were assigned within pair to the basal or the 10% dried skim milk (as-fed basis) finishing diet. Daily feed allowance was 2.6x maintenance DE requirement and was given in two equal meals. Total fecal collection from eight meals and a 96-h urine collection began on d 14 when gilts weighed 92.1 +/- 2.2 kg BW. No differences were found between dietary treatments in gilt's daily N intake (P = 0.33) and the daily output of urinary urea (P = 0.88), urinary N (P = 0.97), fecal N (P = 0.69), and total manure (P = 0.62), as well as apparent total-tract N digestibility (P = 0.84) and N retention (P = 0.84). It is concluded that growing-finishing pigs fed diets containing 10% dried skim milk would have growth performance, carcass traits, and N digestibility and use similar to those fed typical corn-soybean meal diets.     

Effect of protein source and fumaric acid supplementation on apparent ileal digestibility of nutrients by young pigs

Two experiments were conducted to determine the apparent ileal digestibility of DM and N by young pigs fed diets supplemented with different protein sources or organic acids. Pigs were surgically fitted with silicone cannulas at 2 wk of age. Following surgery, pigs were allowed to recuperate with their dams while suckling normally. After weaning at 24 d, pigs were assigned to treatment diets at 28 d of age. A 3-d adjustment and 4-d collection sequence was followed for the duration of the 4-wk experiment. Four treatment diets were fed in each experiment in a weekly rotation until each diet had been fed to each pig. Diet samples and digesta collected through the ileal cannulas were analyzed for chromic oxide (used as an indigestible marker), DM, and N. Pigs in Exp. 1 were fed isolysinic (1.0%) corn-based diets supplemented with casein, soybean meal, soy protein concentrate, or isolated soy protein. Casein addition resulted in improved DM (P less than .001) and N (P less than .05) digestibility but reduced gain (P less than .05) compared with the average of the soy protein sources. Nitrogen from diets formulated with soybean meal was digested more completely (P less than .05) than N from diets based on soy protein concentrate and isolated soy protein. Experiment 2 was an evaluation of the effect of dried skim milk (25%) and fumaric acid (2%) addition on apparent ileal digestibility of N and DM in corn-soybean meal diets. Addition of dried skim milk improved DM (P less than .01) and N (P less than .05) digestibility and daily gain (P less than .001). Fumaric acid supplementation did not affect nutrient digestibility or gain (P greater than .10).     

Evaluation of xylanase and a fermentable xylo-oligosaccharide on performance and ileal digestibility of broiler chickens fed energy and amino acid deficient diets

The objective of this study was to evaluate the effect of a product consisting of a combination of xylanase and xylo-oligosaccharide (STBIO) on performance and ileal digestibility of broiler chickens fed energy and amino acid (AA) deficient diets. Day-old male Ross 308 broiler chicks were randomly allocated to 8 pens per treatment, with 25 chicks per pen. Treatments based on wheat-corn-soybean meal diets were arranged in a 3 × 2 factorial design: a positive control that met or exceeded nutrient recommendations (PC), a negative control diet with a 50 kcal/kg apparent metabolizable energy (AME) reduction (NC1) and NC1 with a 3% reduction in AA content (NC2), each with or without supplementation of 100 g/t of the STBIO. Body weight gain (BWG), feed intake, feed conversion ratio corrected for mortality (FCR) and the European production efficiency factor (EPEF) were recorded from 0 to 42 d. On d 42, ileal samples were collected to determine dry matter (DM), organic matter (OM), ash, protein and energy digestibility. A significant interaction was observed for BWG and feed intake (P < 0.001). The energy and AA reduction reduced (P < 0.05) BWG when compared to the PC. The effect of STBIO on BWG was greater in NC1 (+451 g/bird) than in NC2 (+314 g/bird) or PC (+176 g/bird) diets (P < 0.05), and that in NC2 with STBIO was equal to that in PC without STBIO, and that in NC1 with STBIO was equal to that in PC with STBIO. No interactions were observed on the EPEF or FCR; however, STBIO improved EPEF (P < 0.001) and FCR (P < 0.001) irrespective of the energy reduction or AA density. The intake of digestible DM, OM, ash and energy for the finisher period was increased with STBIO supplementation (P < 0.01). A significant interaction was observed for the intake of digestible protein. NC1 and NC2 reduced the intake of digestible protein; however, when STBIO was supplemented, it was improved in both diets to similar levels to the PC. The stimbiotic supplementation improved performance of broiler chickens fed all diets, particularly those deficient in AME and AA.     

鳙鱼对10种蛋白质饲料原料中营养物质的表观消化率

本试验旨在研究鳙鱼(Aristichthys nobilis)对鱼粉(国产)、干酒糟及其可溶物(DDGS)、菜籽粕、米糠、豆粕、酶解羽毛粉、棉籽粕、小麦麸、玉米蛋白粉和花生粕中干物质、粗蛋白质、粗脂肪、总能以及氨基酸的表观消化率。试验饲料按照基础饲料和待测饲料原料7∶3的比例构成,并添加0.5%的三氧化二钇(Y2O3)作为外源指示剂。挑选初体重为(290.02±2.82)g的鳙鱼,随机分成11组,每组3个重复,每个重复10尾鱼。随机选取1组作为对照组投喂基础饲料,剩余10组为试验组分别投喂试验饲料。投喂1周后通过虹吸法收集粪便。结果表明:1)10种饲料原料中干物质、粗蛋白质、粗脂肪和总能的表观消化率的范围分别为69.9%~85.7%、73.5%~88.3%、81.2%~91.1%和81.9%~86.3%。2)在10种饲料原料中,米糠总能的表观消化率最高,而鱼粉的干物质、粗蛋白质和粗脂肪的表观消化率最高;酶解羽毛粉的干物质、粗脂肪和总能的表观消化率最低,玉米蛋白粉的粗蛋白质的表观消化率最低。3)各饲料原料氨基酸的表观消化率基本维持在65.59%~99.17%,且都以小麦麸较低。由此可见,鳙鱼对鱼粉具有很好的利用效果,其次是豆粕和花生粕,而酶解羽毛粉中粗蛋白质的表观消化率最低,小麦麸各氨基酸的表观消化率均比较低。     

Variation in amino acid digestibility of rapeseed meal studied in caecectomised laying hens and relationship with chemical constituents

1. The objectives were to study the variation in amino acid (AA) digestibility of rapeseed meal in laying hens and to investigate whether the variation in AA digestibility can be explained by chemical constituents of the rapeseed meal. Nine rapeseed meals from different processing plants operating in Germany were used. The crude protein and crude fibre concentrations of the meals ranged from 367 to 410 and 137 to 175?g/kg dry matter (DM), respectively. The concentrations of total glucosinolates varied between 5·1 and 12·9?mmol/kg DM. Each meal was included in one of the experimental diets at an inclusion level of 200?g/kg at the expense of maize starch.

2. A total of 16 Lohmann Brown laying hens were used for this experiment and were surgically caecectomised. They were housed individually in metabolism cages. Each of the 10 diets was fed to at least 6 hens in 4 periods of two weeks duration. Excreta were collected during the last 5?d of each period. The digestibility coefficient of AA was calculated for each diet. The digestibility of the rapeseed meals was calculated by multiple linear regression analysis.

3. Mean essential AA digestibility of rapeseed meals varied between 0·78 and 0·84. Among the essential amino acids, the highest level of digestibility was found for arginine (0·88) and methionine (0·87), and the lowest for lysine (0·74) and threonine (0·75). The highest variation between rapeseed meals in digestibility was found for threonine (0·68 to 0·79) and lysine (0·68 to 0·78). The concentration of neutral detergent insoluble nitrogen of the rapeseed meals was negatively correlated with the digestibility of lysine, but was not significantly correlated with digestibility of any other AA. Glucosinolate concentration was significantly correlated with valine digestibility.

4. Multiple regression analysis showed that the concentrations of crude protein and ash together were the major factors considered to explain variation in digestibility of essential AA. Additional consideration of neutral detergent insoluble nitrogen and total glucosinolates improved the goodness of fit only marginally and was unlikely to be of practical significance.     

Processing conditions affect nutrient digestibility of cold-pressed canola cake for grower pigs

Cold-pressed canola cake is a coproduct of biodiesel production that contains more residual oil than expeller-pressed and solvent-extracted canola meal. Cold-pressed canola cake might be an attractive feedstuff for swine due to local availability from small plants. However, the nutritional quality and content of anti-nutritional factors of cold-pressed canola cake are poorly defined and vary with processing conditions. This experiment evaluated cold-pressed canola cake processed using 4 different conditions: a nonheated and heated barrel at slow and fast screw speed in a 2 × 2 factorial arrangement. Seven ileally cannulated barrows (26 kg of BW) were fed twice daily at 2.8 × maintenance diets containing either 44% of 1 of the 4 cold-pressed canola cake samples, expeller-pressed canola meal, canola seed, or an N-free diet in a 7 × 7 Latin square. The objectives were to measure the energy and AA digestibility and to calculate standardized ileal digestible (SID) AA and NE content. Each 9-d experimental period consisted of a 5-d diet adaptation, followed by 2-d feces and 2-d ileal digesta collections, and 7 observations per diet were obtained. Cold-pressed canola cake contained 41% CP, 16% ether extract, and 5 μmol of total glucosinolates/g (DM basis). Both apparent ileal digestibility (AID) and total tract energy digestibility of energy in cold-pressed canola cake was 36% greater (P < 0.05) in heated vs. nonheated conditions and 8% greater (P < 0.05) in fast vs. slow screw speed without interaction, indicating that heat enhanced energy digestibility. The AID of energy of cold-pressed canola cake was 13 and 118% greater (P < 0.01) than expeller-pressed canola meal and canola seed, respectively. Heat and speed interacted (P < 0.05) for SID of AA of test ingredients, but effects were not consistent among AA. The DE and calculated NE content of cold-pressed canola cake was 0.73 and 0.52 Mcal/kg greater (P=0.001; DM basis), respectively, than expeller-pressed canola meal and did not differ from canola seed. Cold-pressed canola cake averaged 4.17 Mcal of DE/kg, 2.84 Mcal of NE/kg, 0.87% SID Lys, 0.46% SID Met, and 0.79% SID Thr (DM basis). In conclusion, processing conditions greatly affected the digestible nutrient content of cold-pressed canola cake. Content of residual ether extract was an important determinant of the energy value of cold-press canola cake, whereas residual glucosinolates did not seem to hamper nutrient digestibility.     

Effects of preservation method and beta-glucanase supplementation on ileal amino acid digestibility and feeding value of barley for poultry.

1. Effects of preservation method (drying or air-tight storage of whole grain and ensiling of rolled high-moisture grain) and beta-glucanase supplementation (Econase) on apparent ileal amino acid digestibilities and metabolisable energy content of barley were evaluated with Ross broiler chickens. In addition, the effect of barley preservation method was assessed using Leghorn cockerels. 2. Birds were given either a semi-purified soyabean meal basal diet or a mixture of the basal diet and barley (50:50 on dry matter basis). Apparent ileal digestibilities (AID) of nutrients were assessed using the slaughter technique. AID of nutrients and nutrient digestibility measured using excreta (AED) were determined using chromium mordanted straw as an indigestible marker. 3. In broilers, AID of amino acids, dry matter and organic matter were lower for dried than air-tight stored barley, particularly for diets based on ensiled barley. In cockerels, barley preservation method had no effect on amino acid AID. The AED of nutrients and nitrogen corrected apparent metabolisable energy content (AMEn) was highest for ensiled barley across both experiments. 4. beta-glucanase supplementation increased nutrient digestibility, phosphorus retention and AMEn content of air-tight stored and dried barley diets in particular but had only negligible effects on ensiled barley. Beta-glucanase improved the AID of amino acids in dried barley but not in air-tight stored or ensiled barley. 5. Amino acid digestibilities were lower in broilers than cockerels and the effect of barley preservation on feeding value of barley was different for broilers and cockerels.     

In vivo measurement of flatulence and nutrient digestibility in dogs fed poultry by-product meal, conventional soybean meal, and low-oligosaccharide low-phytate soybean meal

OBJECTIVE: To determine an optimal window for determining peak flatulence and evaluate the effects of oligosaccharides and supplemental beta-mannanase in soybean meal-based diets on nutrient availability and flatulence. ANIMALS: 6 dogs. PROCEDURES: Dogs were used in a 2 x 3 factorial arrangement of treatments in a 6 x 6 Latin square experiment to evaluate the digestibility, flatulence, and fecal odor metabolites of low-oligosaccharide low-phytate soybean meal (LLM), conventional soybean meal (SBM), and poultry by-product (PBP) meal diets with or without supplemental beta-mannanase (5 g/kg). RESULTS: Enzyme supplementation had no effect on total tract dry matter (DM), nitrogen digestibility, or digestible energy; however, differences between protein sources did exist for total tract DM digestibility and digestible energy. The PBP meal had higher DM digestibility and digestible energy (mean, 0.913 and 4,255 cal/g), compared with soy-based diets (mean, 0.870 and 4,049 cal/g). No differences were detected for any treatment regardless of protein source or addition of supplemental enzyme for any flatulence components analyzed. No differences were detected for all fecal odor metabolites regardless of addition of supplemental enzyme; however, differences between protein sources were detected. The PBP meal had lower concentrations of carboxylic acids and esters and higher concentrations of heterocycles, phenols, thio and sulfides, ketones, alcohols, and indoles than LLM and SBM. CONCLUSIONS AND CLINICAL RELEVANCE: Diets containing < 22.4 g of stachyose/kg and < 2 g of raffinose/kg did not alter digestibility or increase flatulence in dogs.     

Nutritional evaluation of sunflower seed and products derived from them. Effect of oil extraction

1. Apparent MEn and oil digestibility of hulled sunflower seed (SFS) and the products derived from the oil extraction process: press extracted SFS (PESFS), sunflower seed meal (SFSM), and press and solvent oils (PO and SO) were determined with 198 cockerels. Recombined products (mix of meal and oil) were also evaluated to study the effect of the 2 consecutive oil extraction steps. Each foodstuff was included in a basal diet, according to the proportions resulting from processing, at 100, 200, and 300 g SFS/kg. 2. Dietary energy value and digestible fat content were linearly related to rate of inclusion of test ingredients. Extrapolation values for AMEn (MJ/kg DM) were: SFS, 16.20; PESFS, 9.46; SFSM, 7.62. A decreasing quadratic trend was also found in the AMEn of PESFS, with interpolation values ranging from 11.77 to 9.33 MJ/kg DM between 70 and 210 g/kg DM of inclusion. No differences were observed between PO and SO. The AMEn of of sunflower oil, calculated from its digestibility, was 33.70 MJ/kg DM. 3. The oil extraction process affected the nutritional value of sunflower products. Recombined materials showed greater values than original foodstuffs: R-SFS, 17.47; R-PESFS, 11.49 MJ/kg DM. The increase in oil digestibility (from 0.814 to 0.862 g/kg DM in SFS; from 0.778 to 0.892 in PESFS) accounted for most of the increase observed in AMEn values. 4. As the form in which oil is incorporated in diets (released or within SFS or PESFS) affects the utilisation of sunflower products, their nutritional value is less than maximal and should not be calculated from their ingredients. Solvent oil seems to be the less available fraction of sunflower oil within SFS as the effect of the 2nd extraction proved to be greater than that of the previous press extraction.     

肉鸡能量需要动态模型的建立和参数估计

本研究通过两个试验评价肉仔鸡的能量需要。试验1选用36只AA肉仔鸡新生雏笼养6周,分别于3周龄和6周龄评定2种饲粮的表观代谢能(AME)和表观氮校正代谢能(AMEn)。结果表明:氮校正使AME降低5%左右,AMEn和AME的相关性较强。试验2选用AA肉鸡新生雏240只,公母分饲笼养6周,每周测定空腹体重及采食量。用Compertz方程拟合公母鸡的生长曲线,微分建立日增重与日龄的函数关系,再与利用一元线性回归法建立的能量需要模型组合,形成动态的能量需要预测机制。     

Supplementation of dietary enzymes has varying effects on apparent protein and amino acid digestibility in reproducing sows

The effects of two enzyme (Enz) products on ileal and total tract digestibility (ID and TTD) were evaluated in sows (n = 8) fed corn–soybean meal diets. Treatments were: 1) control diet; 2) control + Enz 1 (protease and cellulase activity); and 3) control + Enz 2 (xylanase activity). Ileal and fecal samples were collected at week 6–7 and 12–13 of gestation and week 2–3 of lactation. There were no improvements in digestibility during gestation. The ID% of dry matter (DM: 77.3, 79.3, 81.7) and N (81.2, 82.5, 84.3) as well as TTD% of DM (89.8, 90.7, 90.8) and N (89.0, 90.0, 90.6) during lactation were affected to varying degrees by the enzymes. The TTD of DM (P = 0.05) and N (P = 0.10) were positively affected by Enz 1. The ID of DM (P = 0.01) and N (P = 0.02) as well as TTD of DM (P = 0.05) and N (P = 0.02) were improved by Enz 2. The improvement in ID of N was not associated with any particular amino acids (AA) but represented small increases in ID of 8 of 10 essential AA with Enz 1 (P = 0.04) and 10 of 10 for Enz 2 (P = 0.01). The product containing xylanase activity, in particular, appears to have potential to increase digestibility of nutrients during lactation in sows.     

玉米理化品质及其鸡代谢能的变异研究

试验测定了55个玉米样品的理化指标和鸡代谢能以评定玉米的营养价值变异。将28日龄体重相近的AA肉仔鸡随机分为不同处理组,每组8个重复,每个重复8只鸡。试验包括1个基础日粮组及待测玉米替代组,添加0.4%TiO2作为外源指示剂。收集32～35日龄排泄物,测定玉米样品的AME和AMEn。结果显示,玉米粗脂肪、粗灰分、酸性洗涤纤维和直支比的变异系数分别为10.35%、12.32%、11.33%和13.51%,其余理化指标变异系数在10%以内。玉米AME和AMEn的变异系数分别为5.97%和5.78%,且不同来源玉米代谢能存在显著差异。从相关性分析结果看,玉米代谢能的差异主要由玉米总能、中性洗涤纤维、酸性洗涤纤维和总淀粉含量的差异所致。     

Effects of xylanase supplementation on the apparent digestibility and digestible content of energy, amino acids, phosphorus, and calcium in wheat and wheat by-products from dry milling fed to grower pigs

Wheat by-products are feedstuffs that vary in nutritional value, partly because of arabinoxylans that limit nutrient digestibility. Millrun is a byproduct from dry milling wheat into flour and contains varying amounts of the bran, middlings, screening, and shorts fractions. The digestible nutrient content of mill-run is not well known. Effects of xylanase supplementation (0 or 4,000 units/kg of diet) on energy, AA, P, and Ca digestibilities were studied in a wheat control diet and 5 diets containing 30% of a by-product (mill-run, middlings, shorts, screening, or bran) in a 2 x 6 factorial arrangement of treatments. The wheat control diet was formulated to contain 3.34 Mcal of DE/kg and 3.0 g of standardized ileal digestible Lys/Mcal of DE. Diets contained 0.4% chromic oxide. Each of 12 ileal-cannulated pigs (32.5 +/- 2.5 kg) was fed 6 or 7 of 12 diets at 3 times the DE requirement for maintenance in successive 10-d periods for 6 or 7 observations per diet. Feces and ileal digesta were each collected for 2 d. Xylanase tended to increase (P < 0.10) ileal energy digestibility by 2.2 percentage units and the DE content by 0.10 Mcal/kg of DM and increased (P < 0.05) ileal DM digestibility by 2.8 percentage units; a diet x xylanase interaction was not observed. Xylanase increased (P < 0.05) total tract energy and DM digestibilities and the DE content. A diet x xylanase interaction was observed; xylanase increased (P < 0.05) total tract energy digestibility of the millrun diet from 72.1 to 78.9%, DE content from 3.19 to 3.51 Mcal/kg of DM, and DM digestibility from 71.5 to 78.6%. Diet affected (P < 0.05) and xylanase improved (P < 0.05) digestibility and digestible contents of some AA in diets and by-products, including Lys, Thr, and Val. Xylanase increased (P < 0.05) Lys digestibility by 13.8, 5.0, 5.2, 6.0, and 14.1 percentage units in millrun, middlings, shorts, screening, and bran, respectively. Diet affected (P < 0.01) total tract P and Ca digestibilities. Xylanase increased (P < 0.05) digestible P and Ca contents. In summary, nutrient digestibility varies among wheat by-products. Millrun contained 2.65 Mcal of DE/kg of DM, which xylanase increased to 3.56 Mcal of DE/kg of DM. Xylanase improved nutrient digestibility and DE content in wheat by-products; and the extent of improvement depended on the by-product. Xylanase supplementation may maximize opportunities to include wheat byproducts in swine diets and ameliorate reductions in nutrient digestibility that may be associated with arabinoxylans.     

东北玉米肉鸡表观代谢能预测方程的建立

本研究旨在通过实验室分析和肉鸡代谢试验建立东北玉米养分含量与代谢能的回归方程,为生产提供便捷的玉米代谢能估算方法。试验1:选取成熟季节不同的20种东北玉米,测定养分含量和容重,分析养分含量变异范围。试验2:用玉米、玉米皮、玉米碴按照中性洗涤纤维(NDF)、酸性洗涤纤维(ADF)含量梯度配制人工玉米,再添加一定量的维生素和矿物质,配制成人工玉米代谢饲粮。选取正常饲养的商品代爱拔益加雄性肉鸡进行代谢试验,分别在11~13日龄及25~27日龄,用全收粪法测定人工玉米代谢饲粮表观代谢能(AME)、氮校正表观代谢能(AMEn)和养分表观消化率,并采用逐步回归法建立AME及AMEn与养分含量的回归方程。结果表明:东北玉米粗脂肪(EE)、NDF及ADF含量变异系数相对较大,分别为16.72%、14.65%、14.72%。肉鸡对人工玉米代谢饲粮的养分表观消化率在11~13日龄和25~27日龄之间存在差异,25~27日龄肉鸡对人工玉米代谢饲粮粗蛋白质(CP)、EE和总淀粉(STC)的表观消化率高于11~13日龄,其中EE表观消化率差异显著(P0.05);25~27日龄肉鸡对人工玉米代谢饲粮的AME、AMEn也显著高于11~13日龄(P0.05)。采用逐步回归法建立肉鸡东北玉米代谢能的预测方程为:11~13日龄,AME=17.661-0.853ADF(R2=0.870,P0.01),AM En=17.468-0.878ADF(R2=0.873,P0.01);25~27日龄,AM E=18.102-0.792ADF(R2=0.781,P0.05),AM En=17.935-0.830ADF(R2=0.784,P0.05)。通过预测方程计算所得人工玉米代谢饲粮AME的预测值与实测值很接近,计算所得的东北玉米AME符合预期值。由此得出,不同品种东北玉米EE、NDF及ADF的含量差异相对较大;肉鸡不同阶段玉米代谢能存在差异,计算肉鸡饲粮配方时,不同阶段饲粮代谢能应采用对应的代谢能值;低于14日龄的肉鸡,东北玉米AM E、AM En预测方程分别为AM E=17.661-0.853ADF,AM En=17.468-0.878ADF;14日龄以上的肉鸡,东北玉米AME、AMEn预测方程分别为AME=18.102-0.792ADF,AMEn=17.935-0.830ADF。     

Digestible and metabolizable energy concentrations and amino acid digestibility of dried yeast and soybean meal for growing pigs

Energy values and amino acid (AA) digestibility of dried yeast (DY) and soybean meal (SBM) were determined in 2 experiments with growing pigs. Experiment 1 was conducted to determine the digestible energy (DE) and metabolizable energy (ME) in DY and SBM. Thirty barrows with a mean initial body weight (BW) of 20.6 kg (SD = 1.04) were assigned to 5 dietary treatments in a randomized complete block design with period and BW as blocking factors. A reference diet was prepared with corn, canola meal, and soybean oil as energy-contributing ingredients. Four additional diets were prepared by adding 5% and 10% DY or SBM at the expense of energy-contributing ingredients in the reference diet. The ratio of corn, canola meal, and soybean oil was kept consistent across the experimental diets. Each experimental period consisted of 5-d adaptation and 5-d quantitative collection of feces and urine. Test ingredient-associated DE or ME intake (kcal/d) was regressed against test ingredient intake [kg dry matter (DM)/d] to estimate the DE or ME in test ingredients as the slope of linear regression model. The DE in DY was estimated at 3,933 kcal/kg DM, which was not different from the estimated DE in SBM at 4,020 kcal/kg DM. Similarly, there was no difference between DY and SBM in the estimated ME (3,431 and 3,756 kcal/kg DM, respectively). Experiment 2 was conducted to determine the standardized ileal digestibility (SID) of AA in DY and SBM. Twenty-one barrows with a mean initial BW of 20.0 kg (SD = 1.31) were surgically fitted with T-cannulas at the distal ileum and assigned to 3 dietary treatments in a randomized complete block design with BW as a blocking factor. Two semi-purified diets containing DY or SBM as the sole nitrogen source and one nitrogen-free diet (NFD) were prepared. The NFD was used to estimate the basal ileal endogenous losses of CP and AA. Pigs were fed the 3 diets for 5 d as adaptation, followed by 2 d of feeding with ileal digesta collection. The SID of AA, except Gly and Pro, in DY was less (P < 0.05) than in SBM. The SID of indispensable AA in DY ranged from 64.1% for Thr to 85.2% for Arg, and those in SBM ranged from 83.9% for Thr to 91.8% for Arg. In conclusion, energy values of DY are not different from those of SBM, whereas AA in DY is less digestible than in SBM. The estimated DE and ME as well as the SID of AA in DY and SBM can be used in diet formulation for growing pigs using these ingredients.     

青鱼对8种饲料原料中营养物质的表观消化率

本试验旨在研究青鱼(Mylopharyngodon piceus)对国产鱼粉、蝇蛆粉、玉米蛋白粉、大豆粕、花生粕、棉籽粕、菜籽粕和米糠8种饲料原料干物质、粗蛋白质、氨基酸、粗脂肪、总磷和总能的表观消化率。试验饲料由70%基础饲料和30%待测饲料原料组成,并以0.1%的三氧化二钇(Y2O3)为外源指示剂。选取平均体重为(60.17±1.28)g的青鱼270尾,随机分成9组,每组3个重复,每个重复10尾鱼。对照组试验鱼饲喂基础饲料,试验组试验鱼分别饲喂1种试验饲料。饲喂1周后采用自排法收集粪便待测。结果表明:8种饲料原料的干物质、粗蛋白质、粗脂肪、总磷、总能以及总氨基酸的表观消化率的范围分别是62.17%～86.47%、83.34%～95.84%、78.93%～100.06%、37.33%～81.99%、66.75%～89.86%、86.33%～96.58%。在8种饲料原料中,玉米蛋白粉的干物质、总磷和总能的表观消化率最高,而大豆粕的粗蛋白质、粗脂肪和总氨基酸的表观消化率最高;棉籽粕的干物质和总能的表观消化率最低,米糠的粗脂肪和总磷的表观消化率最低。各饲料原料中总氨基酸表观消化率与粗蛋白质表观消化率的变化趋势一致,其中以蝇蛆粉最低。由此可见,大豆粕和玉米蛋白粉是青鱼的优质植物蛋白质源,可适量替代鱼粉;蝇蛆粉中粗蛋白质和氨基酸的消化率都较低,在青鱼饲料中的添加量不宜过高;花生粕、棉籽粕和菜籽粕也是较好的植物性蛋白质源,在青鱼饲料中适量添加既有利于饲料的营养平衡,还可降低饲料成本;米糠作为青鱼的能量原料必须保持新鲜,并控制其在饲料中的用量。     

Nutrient digestibility of extruded canola meal in ileal-cannulated growing pigs and effects of its feeding on diet nutrient digestibility and growth performance in weaned pigs

Canola meal (CM) contains less crude protein (CP) and more fiber and anti-nutritional factors such as glucosinolates than soybean meal (SBM) and consequently has a lower nutrient digestibility. Therefore, processing strategies that may increase the feeding value of CM warrant study. In two experiments, the effects of extrusion of Brassica napus CM on apparent (AID) and standardized ileal digestibility (SID) of amino acids (AA), apparent total tract digestibility (ATTD) of gross energy (GE) in growing pigs, and growth performance and diet digestibility in weaned pigs were assessed. Solvent-extracted CM was extruded using a single-screw extruder at three screw speeds: 250 (CM-250), 350 (CM-350), or 450 (CM-450) rpm. In exp. 1, in a double 4 × 4 Latin square, eight ileal-cannulated barrows (initial body weight [BW], 68.1 kg) were fed corn starch-based diets containing 50% CM or extruded CM. The CM sample contained 43.2% CP, 33.2% total dietary fiber (TDF), and 8.9 µmol of total glucosinolates/g on a dry matter (DM) basis. Extrusion increased (P < 0.05) the AID of CP, reduced (P < 0.05) apparent hindgut fermentation of CP, and decreased (P < 0.05) predicted net energy (NE) value of diets. Extrusion increased diet AID and CM SID of most indispensable AA by 3.1 to 5.3%-units. In exp. 2, 200 weaned pigs (initial BW, 8.3 kg) were fed diets containing 20% SBM, CM, or extruded CM starting 2 wk postweaning for 3 wk. The CM sample contained 42.7% CP, 28.3% TDF, and 5.3 µmol total glucosinolates/g DM. Wheat-based diets provided 2.3 Mcal NE/kg and 5.1 g SID Lys/Mcal NE. Dietary inclusion of extruded CM replacing SBM decreased (P < 0.05) diet ATTD of DM, GE and CP, and DE value. Average daily feed intake, average daily gain (ADG), and gain:feed (G:F) of pigs did not differ between extruded CM and SBM diets and were not affected by extrusion, but increasing extruder screw speed linearly increased (P < 0.05) ADG for day 1 to 7 and G:F for the entire trial. In conclusion, extrusion increased diet AID and CM SID of AA but not DE and predicted NE values of CM. However, increasing extruder speed did not further increase the SID of most of the AA of CM in growing pigs. Dietary inclusion of 20% CM or extruded CM did not affect the growth performance in weaned pigs.