Evaluation of corn fiber, cottonseed hulls, oat hulls and soybean hulls as roughage sources for ruminants

An in situ trial (randomized complete block design) using cows, and a site and extent of digestion trial (Latin square design) using sheep were conducted to study the potential of corn fiber (CF), cottonseed hulls (CSH), oat hulls (OH) and soybean hulls (SH) as roughage sources for ruminants. Two feedlot trials with steers and one with lambs (completely randomized design with factorial arrangements of treatments) were conducted to study the potential of CF and SH as energy supplements relative to corn. In situ rate of ruminal dry matter (DM) disappearance (3 to 36 h) and extent of DM disappearance (36 h) indicated that CF and SH were more fermentable in the rumen compared with OH or CSH, with SH being the most fermentable. Total tract digestibilities of DM, organic matter (OM), neutral detergent fiber (NDF) and acid detergent fiber (ADF) were above 70% for sheep fed CF and SH diets, and were 50% or less for sheep fed OH and CSH diets. A ranking of by-products in terms of nutritive value followed the trend: CF greater than SH greater than OH greater than CSH. Lamb feedlot trial data showed that CF was of similar nutritive value to corn and of higher nutritive value than SH at the 50% level of supplementation. Corn-fed lambs responded better than CF- or SH-fed lambs at the 70% level of supplementation. Data from steer feedlot trials showed that CF was of similar quality to corn and of higher quality than SH. Dramatic differences exist in by-product feed utilization by ruminants. All by-products tested appeared to have some usefulness as dietary components.     

Soybean hulls as an alternative feed for horses

Soybean hulls have been successfully fed to ruminant animals as an economical substitute for hay. This feedstuff is a source of highly digestible fiber that does not contain starch. The purpose of this trial was to evaluate soybean hulls as a replacement fiber in horse diets. Four cecally cannulated Quarter Horse geldings, aged 6 to 10 yr and averaging 502 kg, were used in a 4 x 4 Latin square design with 21-d periods. Diets consisted of alfalfa/bromegrass hay (14.4% CP, 58.1% NDF, 39.1% ADF; DM basis) with the replacement of either 0, 25, 50, or 75% (as-fed basis) unpelleted soybean hulls (13.1% CP, 60.6% NDF, 43.7% ADF; DM basis). Diets were offered at 1.8% of BW (DM) daily and body weights were measured weekly. Cecal samples (90 min after feeding) and total fecal collections (3 d) were taken at the end of each treatment period. Fecal collection bags were emptied every 6 h and 10% of the total amount was frozen for later analysis. Total cecal VFA production increased linearly (P = 0.02) from 70 mM to 109 mM as proportions of soybean hulls in diets increased. Proportions of propionate increased linearly (P < 0.01) with means of 15.7, 18.0, 16.6, and 21.9 mol/100 mol total VFA for the 0, 25, 50, and 75% soybean hulls diets respectively. Proportions of butyrate decreased linearly (P < 0.01) from 5.3 to 3.9 mol/100 mol total VFA. The acetate:propionate ratio decreased linearly (P = 0.02) and cubically (P = 0.03) with means of 4.9, 4.2, 4.9, and 3.3. Apparent digestibility of DM (P = 0.95), OM (P = 0.70), NDF (P = 0.34), ADF (P = 0.31), cellulose (P = 0.93), and hemicellulose (P = 0.25) did not differ among treatments. Apparent digestibility of N decreased linearly (P < 0.01) as concentrations of soybean hulls increased in the diet, and this response was associated with increased cecal fermentation and microbial biomass production. Cecal pH decreased linearly (P = 0.01) from 7.00 to 6.45 as the level of soybean hulls increased, but there was no change (P = 0.68 for the linear effect) for cecal ammonia (mean concentration of 3.85 mM). Soybean hulls stimulate cecal fermentation and are a suitable replacement for hay in equine diets.     

Effects of alkaline hydrogen peroxide treatment of cotton and wheat straw on cellulose crystallinity and on composition and site and extent of disappearance of wheat straw cell wall phenolics and monosaccharides by sheep

Effects of alkaline hydrogen peroxide (AHP) treatment on cellulose crystallinity and cell wall phenolic monomer and monosaccharide composition were measured using cotton and wheat straw (WS). Two WS treatments were used in this study, Type I WS, for which pH is not regulated during AHP treatment, and Type II WS, for which pH is regulated at 11.5 +/- .2 during AHP treatment. Wheat straw had a lower degree of cellulose crystallinity than cotton, but no differences occurred between treated and untreated substrates. Alkali-labile and nitrobenzene-extractable phenolic monomer concentrations were generally lower for Type I and Type II WS compared with untreated WS. Concentrations of glucose were higher and xylose and arabinose lower in Types I and II WS than in untreated WS. Disappearance of alkali-labile phenolic monomers and cell wall monosaccharides by wethers fed diets containing Type I (Exp. 1) or Type II (Exp. 2) AHP-treated WS were determined. Apparent digestibility of glucose and xylose before the duodenum, and of glucose, xylose and arabinose in the total tract, was greatest (P less than .05) when sheep were fed AHP-treated WS diets in both experiments. In Exp. 2, disappearance of alkali-labile phenolic monomers was greatest (P less than .05) before the duodenum and in the total tract when sheep were fed AHP-treated WS diets. Treatment of WS with AHP modified cell wall composition and increased cell wall monosaccharide digestion by sheep.     

微生态制剂对玉米秸秆青贮发酵品质、营养成分及瘤胃降解率的影响

本研究以玉米秸秆为研究对象,探讨酶制剂、菌制剂以及酶制剂与菌制剂混合处理对玉米秸秆青贮料发酵品质、营养成分以及瘤胃降解率的影响。玉米秸秆(干物质含量为42%~44%)用青贮切碎机切短至2 cm,将各处理青贮剂溶于蒸馏水,与原料混合均匀后,装入聚乙烯袋(24 cm×40 cm)中,每袋1 kg,然后用真空包装机抽真空封口,室温贮藏45 d后开封取样。采用实验室化学分析法及半体内试验测定发酵品质、营养成分和瘤胃降解率。结果表明,1)与对照组相比,菌制剂(LAB₁ 和LAB₂)处理组pH值和NH₃-N含量均显著降低(P<0.05),乳酸(LA)含量、有机物(OM)及可溶性碳水化合物(WSC)保存量、干物质(DM)、OM、粗蛋白(CP)的瘤胃降解率显著增加(P<0.05);菌制剂处理组的WSC含量显著高于对照组和酶制剂处理(P<0.05)。2)与对照组相比,酶制剂(CE₁和CE₂)处理组pH值、NH₃-N含量、中性洗涤纤维(NDF)、酸性洗涤纤维(ADF)、纤维素均显著降低(P<0.05),乳酸(LA)含量、有机物(OM)及可溶性碳水化合物(WSC)保存量、干物质(DM)、OM、粗蛋白(CP)的瘤胃降解率显著增加(P<0.05);有降低酸性洗涤木质素(ADL)含量的趋势,但是差异不显著(P>0.05)。3)酶菌复合处理组(MCL₁和MCL₂)pH值最低(P<0.05),NDF、纤维素在瘤胃中降解能力显著高于其他处理组(P<0.05),ADL降解率在数值上高于其他组,但差异不显著(P>0.05);与对照组相比,酶菌混合处理组能够降低NDF、ADF、纤维素含量(P<0.05)。综上,酶菌复合添加剂喷洒到秸秆中进行青贮发酵后,能够有效破除玉米秸秆青贮饲料的特殊的木质素-纤维素-半纤维素复合体结构,改善秸秆青贮饲料的发酵品质,提高营养物质的保存量及反刍动物瘤胃对秸秆营养物质的降解率,从而提高秸秆的可利用率,其中MCL₂处理组效果最佳。     

Fruit and vegetable fiber fermentation by gut microflora from canines

The objective of this study was to assess fermentability by canine gut microflora to include shortchain fatty acid (SCFA) production, organic matter (OM) disappearance, and gas production of vegetable and fruit fiber sources compared to fiber standards (psyllium, citrus pectin, and Solka Floc). Fiber sources included apple pomace, carrot pomace, flaxseed, fruit blend (mixture of peach, almond, nectarine, and plum), grape pomace, pea hulls, pistachio, and tomato pomace. Substrates were fermented in vitro for 4, 12, and 24 h with fecal flora obtained from three healthy dogs. Citrus pectin had the highest OM disappearance, SCFA production, and gas production at all times of fermentation; psyllium was intermediate and Solka Floc was lowest. A wide variation in fermentability was noted among the vegetable and fruit fiber sources. Apple pomace, carrot pomace, and flaxseed had the greatest fermentability as assessed by OM disappearance. Pea hulls and tomato pomace had intermediate OM disappearances, and fruit blend, grape pomace, and pistachio were poorly fermented. Carrot pomace produced the largest amounts of gas and SCFA. Apple pomace produced high concentrations of gas but intermediate concentrations of SCFA. Pea hulls and tomato pomace produced intermediate concentrations of gas and SCFA, whereas flaxseed, fruit blend, grape pomace, and pistachio produced low amounts of these fermentation products. For all substrates collectively, OM disappearance was highly correlated with both gas production (r2 = 0.782 and 0.723 for 12- and 24-h values, respectively) and SCFA production (r2 = 0.737 and 0.738 for 12- and 24-h values, respectively). In general, OM disappearance, gas production, and SCFA production were related to the insoluble:soluble fiber ratio in the samples; as the insoluble:soluble ratio decreased (increased soluble fiber), the OM disappearance, gas production, and SCFA production increased.     

Effect of fermentation of cereals on the degradation of polysaccharides and other macronutrients in the gastrointestinal tract of growing pigs

The main objective of the present investigation was to study the impact of fermentation of cereals on the degradation of polysaccharides and other macronutrients in the small intestine and total tract of growing pigs. Eight pigs (initial BW, 34.5 ± 0.9 kg) were used in a replicated 4 × 4 Latin square design. Pigs were cannulated and housed individually in metabolism pens during sample collection. The 4 cereal-based diets were nonfermented liquid barley (NFLB), nonfermented liquid wheat (NFLW), fermented liquid barley (FLB), and fermented liquid wheat (FLW). The fermented feeds were prepared by storing the dietary cereals (barley and wheat) and water [1:2.75 (wt/wt)] in a closed tank at 25 °C for 2 d, after which 50% of the volume was removed and replaced with an equal amount of fresh cereals and water after each afternoon meal. At the time of feeding (0730 and 1430 h), the remaining dietary ingredients were added. Water was added to the dry nonfermented feeds [1:1 (wt/wt)] immediately before feeding. The fermentation process reduced the amount of DM in both cereals (P<0.001), whereas the amount of DM was similar (P=0.626) between the fermented cereals. There was an interaction of cereal and treatment for ileal flow of DM (P=0.014), OM (P=0.013), and protein (P=0.006), which were less in pigs fed the NFLB than the FLB diets, but unchanged in pigs fed the NFLW and FLW diets. Conversely, the ileal flow of protein was similar (P=0.605) in pigs fed the barley diets (average, 47.5 ± 1.7 g/kg of DMI) and increased with the FLW diet compared with the NFLW diet (43 vs. 35 g/kg of DMI, respectively). Ileal fat and CH(2)O digestibilities were 7.6 (P=0.002) and 8.9% (P<0.001) greater, respectively, when pigs were fed wheat compared with the barley-based diets, and the ileal digestibility of CH(2)O was greater when pigs were fed the fermented than nonfermented diets (86.5 vs. 84.5%, respectively; P<0.001). Fermentation reduced (P<0.0001) the fecal excretion of DM, OM, and protein in pigs fed the barley diet, but not when fed the wheat-based diet (P=0.305). Fermentation had no effect (P=0.243) on the fecal digestibility of nonstarch polysaccharides in either of the cereals but their digestibility was 10.0% greater (P<0.001) in pigs fed wheat than the barley-based diets. In conclusion, fermentation of cereal before feeding altered the dietary composition and influenced flow and composition of polysaccharides and other macronutrients at the ileum and in feces to a larger extent for barley than wheat.     

Influence of roughage source on kinetics of digestion and passage, and on calculated extents of ruminal digestion in beef steers fed 65% concentrate diets

Roughage sources were compared in flaked milo-based diets that contained 35% chopped alfalfa hay (AH, control diet) or with cottonseed hulls (CSH) or chopped wheat straw (WS) replacing half the AH. Latin square experiments were used to measure total tract digestion coefficients, particulate passage rates (rare earths), liquid turnover rates (Co-EDTA), and rumination time in six growing steers (Exp. 1) and in situ digestion of DM and NDF, ruminal pH and ruminal DM distribution in three mature, ruminally cannulated steers (Exp. 2). Rates of passage from Exp. 1 and rates and extents of digestion from Exp. 2 were used to calculate apparent extent of ruminal digestion (AED). In Exp. 1, total tract digestibilities of DM and NDF were lower (P less than .05) by 7 and 22%, respectively, when CSH, but not WS, were included in the diet. Digestibility of cell solubles was not different (P greater than .10) among diets. Inclusion of WS increased (P less than .10) rumination time by 36%, and CSH increased intake (P less than .10) by 17% over the control diet. In Exp. 2, there tended to be (P less than .20) increased in situ digestion of milo and AH in the WS diet. Measures of ruminal pH were similar for all diets. The AED for AH and milo DM and NDF, and the proportion of total tract NDF digestion occurring in the rumen (50, 47 and 62% for control, CSH and WS diets, respectively), were highest (P less than .05) for the WS diet. This resulted in similar total tract digestibilities for the WS and AH diets. The two low-digestibility roughages had different effects at this concentrate level; wheat straw enhanced apparent extent of ruminal digestion for NDF of other ingredients in the mixed diets, but cottonseed hulls did not.     

Influence of source and concentrations of dietary fiber on in vivo nitrogen excretion pathways in pigs as reflected by in vitro fermentation and nitrogen incorporation by fecal bacteria

The inclusion of dietary fiber (DF) in diets has been suggested as a way to reduce NH(3) emission in pig barns because it contributes to a shift in N excretion from urine to feces owing to enhanced bacterial growth in the intestines. This study compared an in vitro method to measure bacterial protein synthesis during fermentation with an in vivo N excretion shift induced by diets differing in DF concentrations and solubility. The first experiment measured the effect of graded concentrations of sugar beet pulp (SBP; 0, 10, 20, and 30%) in corn- and soybean meal-based diets on in vivo N excretion partitioning between the urine and feces. A second experiment investigated the replacement of SBP, rich in soluble DF, with oat hulls (OH), rich in insoluble DF (20:0, 10.5:10.5, and 0:22%, respectively). In parallel, the fermentation characteristics of the dietary carbohydrates not digested in the small intestine were evaluated in an in vitro gas test, based on their incubation with colonic microbiota, using a mineral buffer solution enriched with (15)N. The N originating from the buffer solution incorporated into the bacterial proteins (BNI) was measured when half the final gas volume was produced (8.5 to 14.5 h of fermentation) and after 72 h of fermentation. Short-chain fatty acids were determined in the liquid phase. In the first experiment, the inclusion of SBP linearly decreased urinary N excretion from 0.285 to 0.215 g of N excreted in the urine per gram of N ingested and decreased the urinary-N:fecal-N excretion ratio from 2.171 to 1.177 (P < 0.01). In the second experiment, substituting SBP with OH linearly increased the urinary-N:fecal-N excretion ratio (P = 0.009). Unlike short-chain fatty acid production, BNI was greater at half-time to asymptotic gas production than at 72 h of fermentation. Sugar beet pulp enhanced BNI linearly (P < 0.001), 2.01, 2.06, and 2.35 mg g(-1) of diet with 10, 20, and 30% SBP, respectively, as compared with 1.51 mg for the control diet. The substitution of SBP with OH decreased BNI (P < 0.01). With the exception of final gas production, all in vitro kinetic characteristics and BNI were correlated with in vivo N excretion parameters, and regression equations for the prediction of N excretion pathways from in vitro data were identified. Even if the presence of resistant starch in the diet might alter the composition of the fibrous residue that is fermented, the in vitro method is a possible useful tool for the formulation of diets, reducing the effects of pig production on the environment.     

Feed intake, nutrient digestibility and ruminal fermentation activities in sheep-fed peanut hulls treated with Trichoderma viride or urea

This study aimed to assess impacts of fungal treatment on the nutritional value of peanut hulls (PH) or urea at the rate of 5 kg/100 g of PH. Fermented sugar beet pulp inoculated with Trichoderma viride was supplemented to PH at rates of 5.0, 10.0 and 15.0 g/100 g air dry of PH and mixed well before aerobic incubation for 21 days. Organic matter (OM) content of PH declined with increased levels of fermented sugar beet pulp inoculums, while crude protein (CP), ether extract (EE), and ash increased. Fiber contents were decreased with both treatments of fermented sugar beet pulp and urea. Total N of PH increased with urea treatment, which reduced the true protein N to total protein N ratio. In sacco degradabilities of dry matter (DM), OM, and CP with urea treatment increased compared with fungal treatment. The DM intake of peanut hulls treated with fungus (PHF) was higher (P?<?0.05) than with peanut hulls treated with urea (PHU). Digestibility of OM, CP, neutral detergent fiber, and non-fiber carbohydrate by native breed Ossimi sheep with PH were higher (P?<?0.05) than with PH or urea treated PH. The intakes, losses, and balance of N increased (P?<?0.01) with PHF versus PH feeding. Feeding PHF increased (P?<?0.01) ruminal concentrations of NH₃-N, acetic acid, butyric acid, and the acetic to propionic acid ratio. Bacterial and protozoal counts increased (P?<?0.05) with feeding PHF or PHU versus PH. Overall, this fungal treatment of peanut hulls created a higher nutritive value feed for ruminants.     

Modification of a colorimetric analysis for lignin and its use in studying the inhibitory effects of lignin on forage digestion by ruminal microorganisms

The colorimetric acetyl bromide soluble lignin (ABSL) procedure was modified to use for analyzing intact alfalfa and its cell wall fractions for both lignin and total phenolic substances. A purified lignin extracted from alfalfa (native lignin) was used as a standard. Soluble phenolic compounds present in alfalfa did not inhibit cellulose digestion in vitro, because cell wall fractions had the same or slightly lower cellulose digestibility values than did the intact forage (intact forage = 46.5%; Morrison's cell walls = 46.4%; NDF = 42.6%; ADF = 48.7%). Disappearance of ABSL from the solid digesta was very high for intact alfalfa (48.5%), presumably reflecting either solubilization or utilization of the phenolics. However, very little ABSL was detected in the liquid fraction, suggesting that the soluble phenolic substances possibly were metabolized or modified by ruminal microorganisms. On the other hand, little, if any, of the ABSL present in the cell wall fractions disappeared after 48 h of fermentation. These data emphasize the resistance of core lignin to microbial degradation in short-term anaerobic fermentations.     

生物添加剂和含水率对紫花苜蓿和猫尾草青贮发酵品质的影响

试验旨在研究紫花苜蓿绿汁发酵液（AFGJ）、猫尾草绿汁发酵液（TFGJ）、乳酸菌制剂（LAB）、纤维素酶（CEL）及LAB＋CEL（MIX）对紫花苜蓿和猫尾草青贮发酵品质的影响。用紫花苜蓿和猫尾草各2种含水率（高、低）的原料制作了青贮。每个处理设2次重复，常温下贮存50d，开封后测定青贮的发酵品质。研究结果表明，添加剂对紫花苜蓿和猫尾草青贮的发酵品质有显著影响（P〈0．05），除AFGJ和TFGJ高含水率紫花苜蓿青贮外，各种添加剂均不同程度地改善了高、低含水率紫花苜蓿和猫尾草青贮的发酵品质；含水率对紫花苜蓿和猫尾草青贮的发酵品质有显著影响（P〈0．05），2种牧草均是低含水率优于高含水率青贮的发酵品质；添加剂和含水率对青贮的发酵品质有显著的交互作用（P〈0．05）。综合各项指标，在高、低含水率紫花苜蓿青贮中均以添加MIX效果最好；在高含水率猫尾草青贮中，添加TFGJ和AFGJ效果相近且优于其他添加剂；在低含水率猫尾草青贮中添加AFGJ、TFGJ、LAB和MIX效果相近，且优于添加CEL。结果表明，适当降低原料含水率并选择适宜的添加剂可调制优质青贮。     

Improving the nutritional value of oat hulls for ruminant animals with pretreatment of a multienzyme cocktail: in vitro studies

Relatively high amounts of hydroxycinnamic acid in oat hulls, mainly ferulic acid, are believed to be inhibitory to digestion by ruminal microorganisms. Ferulic acid is produced via the phenylpropanoid biosynthetic pathway and covalently cross-linked to polysaccharides by ester bonds and to components of lignin, mainly by ether bonds. Ferulic acid also forms dimers or trimers. As a result, polysaccharides become extensively cross-linked by ferulate dimerization or trimerization and incorporation into lignin. Previous studies have shown that Aspergillus ferulic acid esterase and Trichoderma xylanase act synergistically to release ferulic acid from feruloyl-polysaccharides in complex plant cell walls of oat hulls. This activity opens the remainder of the polysaccharides to further hydrolytic attack and facilitates the accessibility of the main polysaccharide chain to cellulase, thereby increasing the release of reducing sugars. In Exp. 1, the best multienzyme cocktail (ferulic acid esterase, xylanase, cellulase, endo-glucanase [I, II], and beta-glucanase) was developed using an orthogonal experimental design, L25 (5(6)), where L = orthogonal table; 6 = factors; 5 = five levels of each; and 25 = experimental number, for further in situ and/or in vivo study. In Exp. 2, in vitro biodegradation studies with a 3 x 2 x 4 factorial arrangement of treatments were used to evaluate the responses of three feedstuffs, oat hulls or standard references (wheat straw and alfalfa hay), two particle sizes (1 mm and 250 microm), and four in vitro incubation treatments with the best multienzyme cocktail developed in Exp. 1. Addition of the multienzyme cocktail to the forages improved (P < 0.01) in vitro ruminal fluid degradability. With respect to feedstuff, the order of response (P < 0.05) to the treatments was oat hulls (+12% unit) > wheat straw (+5% unit) > alfalfa (+2% unit). This multi-enzyme cocktail seems best suited for oat hulls containing feruloyl ester bonds. In conclusion, data from this study suggest that the addition of the multienzyme cocktail to poorly digestible feeds before feeding enhanced degradation of DM.     

Soybean hulls as a dietary fiber source for dogs.

In Exp. 1, soybean hull samples were obtained from nine sources across the United States and analyzed for nutrient content to determine their suitability for inclusion in dog diets. Compositional data revealed variation in both the amount of total dietary fiber (TDF; 63.8 to 81.2%) in the soybean hulls and the ratio of insoluble:soluble fiber (5.0:1 to 15.4:1). Crude protein content varied widely among sources, ranging from 9.2 to 18.7%. An in vivo trial (Exp. 2) was conducted using a premium dog diet containing 3.0, 4.5, 6.0, 7.5, or 9.0% soybean hulls (DM basis). There was a negative linear effect (P < .05) of soybean hull inclusion in the diet on DM, OM, TDF, and GE total-tract digestibilities, as well as on calculated ME. Crude protein and fat digestibilities were unaffected by treatment. Based on these results, ileally cannulated dogs were fed diets containing 6.0, 7.5, or 9.0% soybean hulls (DM basis) in addition to diets containing either 0% supplemental fiber or 7.5% beet pulp (Exp. 3). Nutrient digestion at the ileum was unaffected by inclusion of supplemental fiber. Total tract digestion of DM, OM, and GE was lower ( P < .05) for diets containing supplemental fiber when compared with the diet containing 0% fiber. Crude protein and fat digestibilities were unaffected by treatment. There was no difference in nutrient digestibility between those diets containing soybean hulls and a diet containing beet pulp. Soybean hull inclusion in the diet resulted in a negative linear effect (P < .05) on calculated ME, in addition to lowering ME (P < .05) when compared with the 0% fiber control diet. Calculated ME for dogs fed a 7.5% beet pulp-containing diet was lower (P < .05) than that for dogs fed the soybean hull-containing diets. Results indicate that soybean hulls can be an effective dietary fiber source in dog diets.     

Estimating diet digestibility: a comparison of 11 techniques across six different diets fed to rams

Six digestion trials were conducted using eight Suffolk rams (four/trial; two trials run concurrently) to determine the ability of 11 techniques to estimate in vivo apparent DM digestibility (DMD). Diets (trials) were as follows: 1) ad libitum access to chopped fescue hay, 2) ad libitum access to alfalfa hay, 3) limit-fed fescue hay, 4) limit-fed alfalfa hay, 5) 25% soybean meal and 75% fescue hay and 6) 40% rolled corn and 60% alfalfa hay. Total feces were collected for 7 d following a 21-d adaptation to each diet. Digestibility methods evaluated were the following: 1) in vitro disappearance (INVITRO); 2) 48 h and 3) 72 h in situ nylon bag (48NB, 72NB); 4) 48NB followed by a 48-h acid pepsin digestion; 5) 96 h and 6) 144 h in vitro fermentation followed by NDF analysis (INDF96 and INDF144) 7) 96 h and 8) 144 h in vitro fermentation followed by ADF analysis (IADF96 and IADF144); 9) ADL ratio; 10) alkaline hydrogen peroxide treatment before ADL analysis (APFPRE) and 11) alkaline hydrogen peroxide treatment after ADF extraction of ADL (ADLPST). Apparent in vivo DMD was accurately estimated (P greater than .10) by INVITRO, ADL and APLPST with Diet 1. However no marker accurately estimated in vivo DMD when fescue was limit-fed. Apparent DMD of Diet 2 was accurately predicted (P greater than .10) by INVITRO, but when Diet 2 was limit-fed, only 48NB and 72NB predicted (P greater than .10) DMD accurately. In vivo DMD coefficients for Diet 5 followed a pattern similar to that of Diet 1. Diet 6 was predicted by INVITRO, 48NB, INDF96, INDF144 and IADF96 (P greater than .10). Results suggest that caution should be exercised when using these techniques, because no single technique provided accurate estimates across all diets and feeding conditions.     

In vitro inhibition of ETEC K88 adhesion by pea hulls and of LT enterotoxin binding by faba bean hulls

Enterotoxigenic Escherichia coli (ETEC) expressing K88 (F4) adhesins are associated with post‐weaning diarrhoea in piglets. Different grain fractions from pea (Pisum sativum) and faba bean (Vicia faba) were tested in vitro for their capacity to counteract aetiological factors, which contribute to the development of diarrhoea. In detail, adhesion of E. coli O149:K91:K88ac (ETEC K88ac) to grain legume products, intended to impair the colonization of the host, was studied as well as interference with receptor binding of the pathogen’s heat‐labile enterotoxin LT, intended to reduce toxin‐inflicted gut cell damage. When comparing different pea and faba bean products tested for their binding capacity of ETEC K88ac, especially pea hulls, but also whole pea meal, starch‐enriched and protein‐enriched pea meal, and digestion‐resistant pea hull and meal fractions showed a higher binding of ETEC K88ac than faba bean products. In contrast to the ETEC K88ac adhesion results, bean hulls proved more effective than pea hulls in preventing GM1 receptor binding of LT. Previous small intestinal segment perfusion experiments we performed with ETEC K88ac‐challenged piglets indicated that both pea and bean hulls have the potential for successful application in diarrhoea prophylaxis and treatment, which is in agreement with and refined by our detection of their different modes of functioning.     

Intake and digestibility of low-quality native grass hay by beef cows supplemented with graded levels of soybean hulls

Twelve Hereford cows and four mature, ruminally cannulated Hereford x Angus heifers were fed supplements providing either 0 (control), 1, 2, or 3 kg/d of soybean hulls and including 440 g of protein/d (cottonseed meal was used to equalize protein intake) to determine the effects of supplementation on intake and utilization of low-quality native grass hay. Cattle were housed in individual pens and fed coarsely chopped (5-cm screen) native grass hay harvested in mid-November (4.1% CP, 76.9% NDF). Hay OM intake peaked (quadratic, P = .04) at 10.1 kg/d with 1 kg of soybean hulls and decreased when 2 kg (9.8 kg/d) or 3 kg (9.1 kg/d) of soybean hulls were fed. Although hay intake decreased when soybean hulls replaced cottonseed meal, feeding 3 kg soybean hulls decreased hay OM intake by only .64 kg. Total OM digestibility increased linearly (P = .009) with added increments of soybean hulls (45.8%, 46.2%, 46.6% and 48.6% for 0 through 3 kg soybean hulls/d, respectively), indicating that hulls were more digestible than the hay. Digestibility of NDF was not affected (P = .14) by level of soybean hull supplementation, although ADF digestibility increased (linear, P = .03). Increases in OM intake and digestibility with soybean hulls combined to increase digestible OM intake (linear, P = .0001). Soybean hull supplementation increased ruminal VFA concentrations (linear, P = .04) and the molar proportion of propionate (linear, P = .006).(ABSTRACT TRUNCATED AT 250 WORDS)     

The presence of inositol phosphates in gastric pig digesta is affected by time after feeding a nonfermented or fermented liquid wheat- and barley-based diet

The objective was to quantify the retention of digesta and evaluate the degradation of phytate or inositol hexakisphosphate (InsP(6)) and lower inositol phosphates (InsP?, InsP?, InsP?, and InsP?) in the stomach at different times after feeding pigs a fermented liquid diet with microbial phytase or a nonfermented diet with or without microbial phytase. Six barrows fitted with gastric cannulas were used. The experiment was a 3 × 3 Latin square with 3 pigs fed 3 diets during 3 wk in 2 replicates. Each experimental period lasted for 7 d, comprising 3 d of adaptation and 4 d of total collection of gastric digesta. For each pig, the digesta was collected once daily at 1, 2, 3, or 5 h after feeding the morning meal. A basal wheat- and barley-based diet was steam-pelleted at 90°C. The dietary treatments were a nonfermented basal diet (NF-BD), the NF-BD with microbial phytase (750 phytase units of phytase/kg, as-fed basis; NF-BD + phytase), and the NF-BD + phytase fermented for 17.5 h (F-BD + phytase). Gastric InsP?-P was not detected at all in pigs fed F-BD + phytase because of complete InsP? degradation during fermentation of the feed before feeding. Gastric InsP?-P decreased over time (P < 0.05) in pigs fed NF-BD and NF-BD + phytase. The decreases were 45, 54, 56, and 61 percentage points greater at 1, 2, 3, and 5 h, respectively, in pigs fed NF-BD + phytase compared with NF-BD. However, substantial amounts of InsP? still passed into the small intestine in pigs fed NF-BD + phytase, especially within the first hour (estimated to 17% of InsP?-P intake). The accumulation of lower inositol phosphates in gastric digesta was very small for all treatments and at all times because of a rapid and almost complete degradation. In conclusion, phytase addition to the nonfermented diet increased the degradation of gastric InsP?. However, considerable amounts of intact InsP? still passed into the small intestine because of a shortage of time for InsP? degradation in the stomach. Therefore, to increase the apparent digestibility of plant P in dry wheat- and barley-based diets, the development of phytases that can degrade InsP? effectively immediately after ingestion of the feed at an initial gastric pH from 6.5 to 5.0 is needed. Feeding F-BD + phytase compensated for the shortage of time because the InsP? degradation was completed during fermentation before feeding. The degradation of InsP? to InsP? is the bottleneck for plant P utilization in pigs because the degradation of the lower inositol phosphates is rapid and almost complete.     

Effect of intermittent feeding and oat hulls to improve phytase efficacy and digestive function in broiler chickens

1. Two trials were carried out to investigate the impact of intermittent feeding and oat hulls as methods to stimulate the anterior digestive tract in broiler chickens.

2. In Trial 1, 7-d-old broilers were placed 4 per cage in 48 cages and fed either ad libitum or intermittently on a diet with 50 g/kg of either oat hulls or cellulose, with or without 1000 FTU phytase, in a 2 × 2 × 2 factorial arrangement. Ad libitum fed birds had two 4-h dark periods with 1-h light in between, while intermittently fed birds in addition had restricted access to feed through four 1 h feeding bouts.

3. In Trial 2, 144 broiler chickens were divided amongst 12 pens which were intermittently fed on the same diets as in Trial 1 in a 2 × 2 factorial arrangement. At 34 d of age, after 16 h feed withdrawal, birds were fed for 1 h, followed by dissection of 4 birds per treatment every hour for 9 h. Contents from different segments of the digestive tract were collected quantitatively to assess dry matter (DM) and starch flow.

4. In Trial 1, phytase improved performance and nutrient availability, while oat hulls and intermittent feeding improved some measures of nutrient availability. Intermittent feeding augmented the effect of phytase on myo-inositol hexakisphosphate (IP6) degradation in the anterior digestive tract.

5. In Trial 2, birds filled up their crop and slowly passed these contents on to lower segments of the digestive tract. Already 1 h after commencement of feeding, the entire length of the small intestine was filled with DM, and no significant changes in DM content were observed before 4–5 h later, when the small intestine gradually became emptied. The tendency for a higher initial load of DM and starch in birds without oat hulls seems to support the hypothesis that one important function of the gizzard is feed-flow regulation.

6. In conclusion, the anterior digestive tract seems to have an important regulative function in broiler chickens when stimulated by intermittent feeding or structural components. More research is needed in order to elucidate the role of the crop and gizzard for phytase function.     

解淀粉芽孢杆菌复合菌剂对玉米秸秆的降解作用及表征

为获得能提高秸秆饲草品质的微生物发酵菌剂,本研究在前期获得2株具有木质素和纤维素降解能力的解淀粉芽孢杆菌菌株的基础上,将两者混配成复合菌剂,考察复合菌剂对玉米秸秆的降解作用,并通过傅立叶红外光谱(FTIR)、核磁共振氢谱(¹H-NMR)、扫描电镜(SEM)及气质联用色谱(GC/MS)等技术对玉米秸秆的微观结构及降解产物进行表征。研究发现,复合菌剂可以有效降解玉米秸秆中的木质纤维素。在发酵24 d时,玉米秸秆中木质素、纤维素和半纤维素的降解率分别达到48.4%,30.5%和41.4%。FTIR和¹H-NMR谱图中能观察到木质纤维素分子结构中主要连接共价键,如木质素单体间的β-O-4和β-β键、木质素与碳水化合物连接键以及碳水化合物中糖环内的价键等明显断裂,木质纤维素被部分降解;SEM扫描电镜图则显示发酵后秸秆的组织结构出现松散和破坏。发酵后秸秆中小分子物质的GC/MS分析结果显示,其中包含苯丙胺和苯丙酸等保留苯丙烷结构单元的木质素单体衍生物以及苄醇和苯甲酸酯类等木质素单体被进一步降解后的芳香族化合物。玉米秸秆中碳水化合物的GC/MS分析结果表明:复合菌剂可将玉米秸秆中的结构性多糖等大分子碳水化合物降解成葡萄糖、木糖、甘露糖及乳糖等还原性单糖。并利用这些还原性单糖生长代谢,进一步产生乙二醇、丙三醇及短链脂肪酸类等代谢产物。以上研究结果表明,解淀粉芽孢杆菌复合菌剂可有效降解玉米秸秆中的木质纤维素,在玉米秸秆饲草化利用中极具应用前景。     

Feeding value of diets containing almond hulls

Four mature geldings were used in a 4 X 4 Latin Square digestion experiment to determine the digestibility of pelleted diets containing 0. 15, 30 and 45% Nonpareil almond hulls. The four isonitrogenous treatments consisting of almond hulls, oat hay, and alfalfa hay provided approximately 94% dry matter (DM), 11% crude protein (CP), 23-32% acid detergent fiber (ADF) and 4100 kcal/kg gross energy (GE). Each horse consumed a different diet during each of four 14-day trial periods. Horses were fed 10 kg of their assigned diet per day. The horses gained an average of 15 kg over the course of the 8-week study. No feed was refused in any of the trials and there were no signs of adverse reactions to any of the diets. The digestibilities of the four dietary components (DM, CP, ADF and GE) were not affected by horse or trial period. Dry matter and GE digestibilities increased (P<.05) as the almond hull content increased in the four diets (59, 63, 64 and 68% DM digestibility and 57, 61, 61 and 64% GE digestibility, respectively). Acid detergent fiber digestibility was not affected by almond hull content (39, 39, 39 and 42% digestibility, respectively) while CP digestibility decreased as the almond hull content increased in the four diets (69, 62, 66 and 56% digestibility, respectively). Almond hulls appear to be a safe and palatable feed for horses and can be fed up to levels of 45%.