The effect of replacing nonstructural carbohydrates with soybean oil on the digestibility of fibre in trotting horses

The hypothesis tested was that the intake of extra fat at the expense of an isoenergetic amount of nonstructural carbohydrates reduces fibre utilisation in horses. In a crossover trial with feeding periods of 42 days each, 6 mature trotting horses (age 4-12 years, bodyweight 340-476 kg) were given either a control or test diet. The test concentrate was formulated to contain 37% of net energy in the form of soybean oil. The control concentrate contained an isoenergetic amount of corn starch plus glucose. The concentrates were fed in combination with the same amount of hay so that the control and test diet contained 25.13 and 86.66 g crude fat/kg dry matter, respectively. Apart from the amounts of fat and nonstructural carbohydrates, the 2 diets were identical. The test diet reduced the apparent total tract digestibilities of crude fibre, neutral and acid detergent fibre by 8.0 (P = 0.007), 6.2 (P = 0.022) and 8.3 (P = 0.0005) percentage units, respectively. It is suggested that a high fat intake by horses may increase the amount of fat entering the large intestine to levels that depress fermentation by cellulolytic bacteria. The observed interaction between fat content of the diet and fibre utilisation may have consequences for practical horse feeding in that calculating the energy content of test diets on the basis of feedstuff tables leads to overestimating the amount of energy provided by the high-fibre ingredients of the diets.     

Dietary soyabean oil depresses the apparent digestibility of fibre in trotters when substituted for an iso-energetic amount of corn starch or glucose

The aim of the present study was to establish whether the inhibitory effect of fat feeding on fibre digestion has been underestimated due to the substitution of fat for corn starch. A high fat intake has been shown to lower total intestinal tract apparent digestibility of crude fibre in horses but, since fat was substituted for nonstructural carbohydrates, including starch, the specific effect of fat could not be ascertained. The possibility could not be excluded that starch also inhibits fibre digestibility, so that the fat effect observed earlier would have been underestimated. In this study, the intakes of iso-energetic amounts of soyabean oil, corn starch or glucose were compared as to fibre digestibility. Unlike starch, glucose is fully absorbed by the small intestine and, therefore, is not expected to influence fibre fermentation in the caecum and colon. Six trotters were fed rations high in soyabean oil (158 g/kg dry matter), corn starch (337 g/kg dry matter) or glucose (263 g/kg dry matter) according to a 3 x 3 Latin square design. Apparent crude fibre digestibility was similar for the rations with corn starch (mean +/- s.d., 70.7 +/- 3.06% of intake, n = 6) or glucose (71.0 +/- 1.90%), but was significantly depressed by fat feeding (56.5 +/- 7.65%). Similar observations were made for apparent digestibilities of neutral and acid detergent fibre and of cellulose. It was concluded that the addition of fat to the feed ration of horses has a specific inhibitory effect on fibre utilisation and, therefore, reduces the amount of energy provided by dietary fibre.     

奶牛日粮添加豆油和胡麻油对有机物和纤维物质消化率的影响

选用4头装有永久性瘤胃瘘管的初产奶牛采用4×4拉丁方设计，研究不添加油脂（CK）、添加4％豆油（LOC1）、4％胡麻油（LOC2）以及2％豆油+2％胡麻油（LOC3）对DM、OM、NDF、ADF瘤胃表观消化率及全肠道消化率的影响。结果表明：在60%高粗料日粮基础上添加4%豆油、亚麻油或二者的混合物，对奶牛干物质采食量没有影响。与对照组相比,添加油组DM、OM、NDF、ADF的瘤胃表观消化率和全肠道消化率都有降低的趋势，但差异不显著（P＞0.05），3个添加油组之间差异也不显著（P＞0.05）。     

ORIGINAL ARTICLE: Impact of feeding level on digestibility of a haylage‐only diet in Icelandic horses

Eight mature Icelandic geldings were used in an experiment arranged as a change‐over design to evaluate the effect of feeding level on the digestibility of a high‐energy haylage‐only diet. The horses were fed a low feeding level 10.7 g dry matter (DM)/kg body weight (BW) (maintenance) and a high feeding level 18.1 g DM/kg BW (1.5 × maintenance) during two 23 days experimental periods. Total collection of faeces was performed for 6 days at the end of each period to determine the coefficient of total tract apparent digestibility (CTTAD). The CTTAD for DM, organic matter, neutral detergent fibre (NDF), acid detergent fibre and energy was higher in horses fed at the low level of feed intake, while feeding level did not affect the CTTAD of crude protein. The largest difference in CTTAD between feeding levels was found for NDF. The content (/kg DM) of digestible energy in the haylage was 11.3 MJ at the low level of feed intake and 10.6 MJ at the high level of feed intake. It can be concluded that feeding level has a large impact on the digestibility and energy value of early cut haylage in Icelandic horses.     

Effect of dental correction on voluntary hay intake,apparent digestibility of feed and faecal particle size in horse

Summary In nine adult Warmblood horses with mild to moderate dental findings (no signs of discomfort during chewing), voluntary hay intake before and after dental correction was examined. In a second experiment, digestibility of feed and faecal particle size were determined (3 days of total faecal collection) before and after dental correction. During both digestion trials including a 3‐day adaptation period, the amount of hay and concentrate (mixture of oats, barley and maize) was kept constant in each individual horse before and after dental correction. Voluntary hay intake in individual horses ranged from 11 to 22 g DM/kg BW/day and did not differ before and after dental treatment. Apparent digestibility of DM, energy, crude fibre and Nfe increased significantly after dental correction (energy digestibility before dental correction 46.8 ± 7.4%, after dental correction 51.5 ± 8.5%). Apparent digestibility of feed was higher in horses eating more concentrates than in those eating less concentrates. Improvement of digestibility was more marked in horses eating larger amounts of grain. There was no relationship between severity or type of dental alterations and improvement of apparent feed digestibility. Dental correction had no effect on faecal particle size.     

Apparent metabolisable energy and digestibility of shea (Vitellaria paradoxa) fat, cocoa (Theobroma cacao) fat and soybean oil in broiler chicks

1. The objective of this experiment was to determine and compare the apparent lipid digestibility coefficient and apparent metabolisable energy (AME) value of shea nut (Vitellaria paradoxa, Gaertn.) fat in broiler chickens with that of soybean oil and cocoa fat. 2. One hundred and sixty 13-d-old male broiler chicks were used in a randomised complete block design. The fats were added at 30, 60 and 90 g/kg to a basal diet. A tenth dietary treatment was the basal feed with no added fats or oils. The birds were fed on the diets for 8 d and all droppings were collected for the final 4 d. 3. The mean coefficient of apparent lipid digestibility for shea fat (0.58) was similar to that of cocoa fat (0.54) but lower than that of soybean oil (0.95). There was evidence of a lipid x concentration interaction with the 90 g/kg shea fat diet having low lipid digestibility (0.43). 4. There was an interaction between the effects of dietary lipid concentration and test lipid on AME but, at dietary levels of 60 g/kg and below, the AME of shea fat (22.0 MJ/kg DM) and cocoa fat (26.4 MJ/kg DM) was significantly lower than that of soybean oil (39.8 MJ/kg DM).     

Source and level of energy supplementation for yearling cattle fed ammoniated hay

Brahman x British crossbred steers were used in growth and digestion trials to evaluate the response of source (corn, sugar cane molasses, or soybean hulls) and feeding rate (0, 1.4, or 2.8 kg DM per steer daily in the growth trials; 0, 15, or 30% of the ration DM in the digestion trial) of energy supplementation in cattle fed ammoniated (4% of forage DM) stargrass (Cynodon nlemfuensis Vanderyst var. nlemfuensis) hay. Cattle on all treatments were fed 0.5 kg cottonseed meal daily. In the growth trials, steers grazed dormant bahiagrass (Paspalum notatum) pasture. Increasing the levels of supplementation decreased hay intake but increased total dietary intake for all diets (P < 0.07). Daily gain and feed efficiency of steers were improved (P < 0.03) with supplementation. Steers supplemented with corn or soybean hulls at 2.8 kg DM/d had a higher ADG (0.92 kg) and gain/feed (0.103) than steers supplemented with molasses (0.78 kg, 0.08, respectively) at the same level. Seven crossbred steers (200 kg) were used in a five-period digestion trial to evaluate apparent OM, NDF, ADF, and hemicellulose digestibility. Apparent OM digestibility of all diets increased linearly (P = 0.02) as the level of supplementation increased. Apparent NDF and ADF digestibility decreased (P < 0.03) as the level of supplementation with corn or molasses increased, whereas increasing the level of soybean hulls in the diet increased (P < 0.06) apparent NDF and ADF digestibility. Four ruminally fistulated crossbred steers (472 kg) were used in a 4 x 4 latin square design to investigate ruminal characteristics with energy supplementation at 30% of ration DM. Ruminal pH in steers supplemented with soybean hulls or corn declined after feeding. Ruminal pH decreased more rapidly with corn supplementation and remained below 6.2 for a longer period of time than with the other diets. Ruminal pH did not change within 24 h after feeding for steers fed the control or molasses diets. No change in total VFA concentration was observed in steers fed molasses or corn. Total ruminal VFA concentration in steers supplemented with soybean hulls increased initially after feeding and then declined within 24 h after feeding. Soybean hulls produced fewer negative associative effects than corn when fed with ammoniated stargrass hay at 2.8 kg DM/d. The reduced gain/feed of steers supplemented with molasses compared to soybean hulls or corn indicates that molasses was not utilized as efficiently as the other energy sources.     

Effect of dietary medium chain triacylglycerols on plasma triacylglycerol levels in horses.

The hypothesis tested was that the feeding of medium chain triacylglycerols (MCT) to horses would raise the level of plasma triacylglycerols by increasing the availability of glucose as lipogenic substrate, implying that the MCT effect would be greater with glucose in the diet instead of cellulose. A Latin square experiment was carried out with 4 horses and 4 dietary treatments. The experimental periods lasted 21 d. Blood samples were taken 16 h after feeding. The diets consisted of hay and experimental concentrates, differing in fat source (MCT or soybean oil) and carbohydrate source (corn starch plus glucose or cellulose). The dietary variables, MCT or soybean oil, provided on average 27% of total dietary net energy, while glucose plus constarch or cellulose provided 33%. The feeding of MCT versus soybean oil raised the level of plasma triacylglycerols significantly from 196.7 +/- 30.2 to 427.3 +/- 85.7 mmol/l and that of VLDL cholesterol from 0.028 +/- 0.01 to 0.069 +/- 0.01 mmol/ml. As based on analysis of variance, for the four experimental diets there was no significant effect of carbohydrate source and no fat-carbohydrate interaction. Thus, the hypothesis was rejected. When the diets contained soybean oil, cellulose versus starch plus glucose produced significantly greater increase plasma triacylglycerols. This carbohydrate effect was not seen when horses were fed the MCT diets. The experimental concentrates did not differently influence the concentrations of plasma glucose, total serum cholesterol, phospholipids, insulin, free fatty acids and the activity of post-heparin lipoprotein lipase. We suggest that the MCT-induced increase in plasma triacylglycerols is related to an increase in hepatic VLDL secretion, with the extra substrate for increased synthesis of triacylglycerols being the acetyl-CoA derived from the hepatic oxidation of medium chain fatty acids.     

Effect of partial replacement of oats with sugar beet pulp and maize oil on nutrient utilisation in horses.

The objective of the present work was to assess the influence of partial replacement of oats with dried unmolassed sugar beet pulp (SBP) and/or maize oil on nutrient utilisation in horses fed a traditional hay and concentrate diet. The total tract digestibility of nutrients, urinary excretion and plasma parameters were studied in a 4 x 4 Latin-square design experiment with purebred Arabian geldings. Horses fed the SBP diets responded with a reduced (P<0.05) apparent digestibility of crude protein and feeding of maize oil resulted in an increased (P<0.05) apparent digestibility of crude fat. The apparent energy digestibility was unaffected by the replacement of oats with SBP, but increased (P<0.05) when maize oil replaced part of the oats. The urinary excretion of nitrogen increased (P<0.05) when maize oil replaced oats and the excretion of energy was higher (P<0.05) on the diets where oats were replaced by maize oil and SBP. There was a significant (P<0.05) effect across treatments of postprandial blood sampling time on plasma glucose and insulin concentrations. Also, plasma concentrations of glucose and insulin tended to be higher on the oats than on the SBP diets. In conclusion, the limited effects on the digestibility of nutrients and energy suggest that it should be possible to partially replace oats with maize oil and/or SBP in diets for horses without any impairing effects on the overall nutrient utilisation. However, the dietary-induced changes in the urinary excretion of energy and on plasma glucose and insulin levels, indicate a possible influence of dietary carbohydrate composition on nutrient utilisation at the organ level, which requires further study.     

Elephant grass, sugarcane, and rice bran in diets for confined sheep

We aimed to evaluate the effects of diets, based on elephant grass or sugarcane as roughage and corn meal or rice bran as energy concentrate, on performance and body composition in terms of diet intake and digestibility. A total of 30 Santa Ines crossbreds (SIC), castrated male sheep with 19.8?±?2.0?kg initial body weight (BW) were used. Six animals were slaughtered at the onset of the experiment to estimate the initial body composition for the other animals. The remaining 24 animals were distributed in a completely randomized 2?×?2 factorial design, with four treatments (two roughages and two concentrates) and six replicates. The sheep were slaughtered when they reached 30.0?kg BW. Elephant grass diets provided higher intake and digestibility than sugarcane diets for the following contents: dry matter (DM), organic matter (OM), crude protein (CP), neutral detergent fibre, minerals, total carbohydrates (TC), and total digestible nutrients (TDN). Among the concentrates, corn meal diets were associated with higher intakes than rice bran diets for the following contents: DM, OM, CP, TC, and TDN. Animals from all of the treatments exhibited low average daily weight gain and low protein and high fat and energy body levels. Sugarcane and rice bran can be used as ingredients in diets for sheep with low weight gain potential. Regardless of roughage or concentrate types used in diets for confined SIC sheep, performance and body composition remained unaltered.     

Evaluation of various extracted vegetable oils, roasted soybeans, medium-chain triglyceride and an animal-vegetable fat blend for postweaning swine

A total of 280 crossbred pigs weaned at 21 d of age and weighing approximately 6 kg were utilized in five replicates to evaluate pig growth responses when fed a basal diet or one of several dietary lipid sources during a 4-wk postweaning period. A basal corn-soybean meal-corn starch-dried whey diet was compared with diets supplemented at a 7.75% level with one of the following lipid sources: corn oil, coconut oil, soybean oil, medium-chain triglyceride (MCT) or an animal-vegetable blend. A sixth treatment evaluated a roasted soybean diet formulated to an energy:lysine level equivalent to that of the fat-supplemented diets. In Exp. II, 36 crossbred weanling barrows were used to determine apparent fat and N digestibilities when soybean oil, roasted soybean, coconut oil or the MCT-supplemented diets were fed. Although pigs fed coconut oil grew somewhat faster, fat inclusion generally did not increase pig growth rate or result in lowered feed intake during the initial weeks postweaning; during the latter portion of the starter phase the addition of dietary fat resulted in a higher growth rate but feed intake was unaffected, resulting in an overall improvement in feed-to-gain ratio (P less than .05) for all but the roasted soybean diet. Pigs fed coconut oil had higher serum triglyceride and lower serum urea concentrations than did pigs fed diets containing most other lipid sources. Pigs fed MCT and coconut oil diets had a higher (P less than .01) apparent fat digestibility during the initial 2 wk postweaning than pigs fed soybean oil or roasted soybean diets. Pigs fed MCT and roasted soybeans had poorest growth rates; apparent fat and N digestibilities were lowest (P less than .05) for the roasted soybean diet.     

Spelt, an ancient cereal and first pressure linseed oil as ingredients of compound feedstuffs for modern horse feeding

Spelt is a covered cereal with large glumellas. In experiment 1, it has been compared in terms of chemical composition with barley, oat and maize. Spelt is characterized by rather low protein and ether extract (EE) contents. The neutral detergent fibre (NDF) content of spelt was slightly higher than that of oat but the acid detergent fibre (ADF) content was lower. Two compound feedstuffs were fed along with hay to six horses used in a cross-over design. Both diets were well appreciated by the horses and there were no significant differences in the apparent digestibility coefficients, except for EE which was significantly higher, when oat was included in the compound feedstuff. In experiment 2, first pressure linseed oil was incorporated at a rate of 8% in a control compound feedstuff, where the barley was partly substituted by the oil. The fat content was 9.6% dry matter (DM) in the linseed oil compound feedstuff and 5.4% in the hay-concentrate ration. The inclusion of linseed oil increased the digestibility of DM, EE and NDF of the diet. There were no effects on the post-prandial concentrations of glucose, triglycerides and non-esterified fatty acids (NEFA) but the insulin concentration was significantly reduced with the linseed oil inclusion. There were significant increases in the plasma concentrations of the total fatty acids, polyunsaturated fatty acids (PUFA), saturated fatty acids (SFA), C18:3 n-3 and C18:2 n-6 and significant reductions in the contents of monounsaturated fatty acids (MUFA), C18:1 n-7 + n-9 and C20:4 n-6. It is concluded that the inclusions of spelt and first pressure linseed oil in compound feed stuff for horse are of interest for modern horse feeding.     

Effect of feeding different levels of foliage from Cratylia argentea to creole dairy cows on intake, digestibility, milk production and milk composition

The effect of feeding different levels of foliage from Cratylia argentea (Desvaux) O. Kuntze to dairy cows on intake, digestibility, milk production and milk composition was studied in the dry tropics in Nicaragua. The treatments were sorghum silage ad libitum, either unsupplemented or supplemented with 2 kg or 3 kg of Cratylia on a dry matter (DM) basis. Six Bos indicus cows of the Creole Reyna breed, with a mean body weight of 386 (SD 19) kg were used in a replicated 3×3 Latin square design. Supplementation with Cratylia increased (p < 0.05) DM intake from 6.6 to 7.8 and 8.7 kg DM/day and milk production from 3.9 to 5.1 and 5.7 kg/day for sorghum silage alone and supplementation with 2 kg and 3 kg DM of Cratylia, respectively. Milk fat, total solids and crude protein and organoleptic characteristics (smell, taste and colour) were not significantly different among diets. The apparent digestibility coefficients of dry matter, organic matter, neutral detergent fibre and acid detergent fibre were not affected significantly by supplementation with Cratylia. However, crude protein (CP) digestibility increased (p < 0.05) in the diets supplemented with Cratylia compared to sorghum silage alone. In conclusion Cratylia given as a protein supplement to a low-quality diet improved DM intake and CP digestibility of the diet and increased milk production, but did not affect milk composition.     

Digestibility and nitrogen utilization in sheep fed enset (Ensete ventricosum) pseudostem or corm and graded levels of Desmodium intortum hay to wheat straw‐based diets

The aim of this study was to investigate the effects of different levels of Desmodium intortum (Desmodium) hay supplementation in sheep fed fixed amounts of enset pseudostem or corm and a basal diet of wheat straw on intake, digestibility and nitrogen utilization. Eighteen male sheep with a mean (± SD) live weight of 20.5 ± 1.45 kg were assigned to six treatments in a completely randomized design and fed either 108 g dry matter (DM) enset pseudostem or 165 g DM enset corm each with three levels (100, 200 and 300 g) of hay supplementation. For the pseudostem diets, there was no significant difference in total DM intake. Total crude protein (CP) intake and N retention increased with increasing levels of hay in both pseudostem and corm diets. The apparent digestibility of DM, OM, CP, acid detergent fibre and neutral detergent fibre (NDF) and microbial nitrogen supply (MN) at 100 g was lower that other levels of supplementation. For the corm diets, total DM and OM intake and MN supply increased with increasing levels of hay. The digestibility decreased (p < 0.001) with increasing levels of supplementation. The results suggest that at least 300 g (395 g/kg dietary DM) of Desmodium hay is required in pseudostem diets, whereas 200 g (337 g/kg dietary DM) may be sufficient in corm diets for efficient nutrient utilization.     

日粮添加不同油脂原料对肉牛生长性能、养分消化及瘤胃发酵性能的影响

文章旨在探讨日粮添加不同油脂原料对肉牛生长性能、养分消化及瘤胃发酵性能的影响。试验选择平均初始体重（296±32.33）kg、带有瘤胃瘘管的肉牛48头,随机分为4组,每组4个重复,每个重复3头。对照组肉牛饲喂不含油脂的日粮,处理组肉牛分别饲喂含有5%棕榈油、亚麻油和包被脂肪的日粮。在为期10周的饲养试验后测定相关指标。结果：对照组与包被脂肪组干物质、有机物和氮摄入量及干物质、有机物表观消化率显著高于棕榈油和亚麻油组（P＜0.05）,而包被脂肪组与亚麻油组粗脂肪摄入量显著高于对照组和棕榈油组（P＜0.05）。对照组粗脂肪表观消化率较其他组分别显著降低31.94%、32.17%和33.56%（P＜0.05）,而亚麻油组中性洗涤纤维表观消化率较其他组分别显著降低18.61%、17.10%和19.68%（P＜0.05）。包被脂肪组瘤胃不饱和脂肪酸流量较对照组和棕榈油组分别显著提高152.26%和240%（P＜0.05）。对照组与包被脂肪组瘤胃氨氮浓度显著高于棕榈油组和亚麻油组（P＜0.05）。结论：包被脂肪降低了脂肪对瘤胃发酵的影响,其对瘤胃饱和脂肪酸流量的影响与亚麻油相似,但棕榈油降低了瘤胃氨氮浓度,不能有效向瘤胃提供不饱和脂肪酸。 [关键词]油脂原料|肉牛|生长性能|养分消化|瘤胃发酵     

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。     

Comparison of Nutrient Digestibility Between Adult and Aged Horses

There is little published work comparing digestibility in healthy adult versus healthy aged horses. Researchers hypothesized that there would be no differences in macronutrient digestibility between eight adult (5–12 years) and nine aged (19–28 years) horses fed three diets in a Latin square design. Seventeen stock-type mares were randomly assigned for a 5-week period to one of three diets: hay only (HAY), hay plus a starch- and sugar-rich concentrate (CHO), or hay plus a fat- (oil) and fiber-rich concentrate (FF). Each diet period comprised 3 weeks of outdoor group drylot feeding, 2 weeks of indoor stalled individual feeding, followed by a 72-hour digestibility trial including total urine and fecal collection. Feed, fecal, and/or urine samples were analyzed to determine dry matter, crude protein, fat, energy, calcium, and phosphorus apparent retention as well as apparent digestibility. Neutral detergent fiber digestibility was also determined. Mean body weight was lower in aged than in adult horses (455 ± 12 kg vs. 500 ± 13 kg; P = .02), but body condition score (BCS) did not differ between groups (aged horses, 4.8 ± 0.2 BCS and adult horses, 5.1 ± 0.2 BCS; P = .20). No age differences in digestibility, apparent digestibility, or apparent retention were seen for any of the variables measured. Based on the results of this study, total tract macronutrient digestibility appears to be similar between healthy adult and aged horses.     

Plasma glucose concentrations and digestibility of dry matter, energy and crude protein in mature geldings fed wheat and oat-based diets

Eight mature stock horse geldings were used in two simultaneous 4×4 Latin square experiments to determine the effect of feeding graded levels of wheat and oats on post prandial glucose concentrations and digestibility of dry matter (DM), energy and crude protein (CP). Experimental concentrate diets consisted of 100 (W), 66 (WO), 33 (OW) and 0 (O) percent wheat with the balance as oats. Concentrate diets were fed in a 60:40 ratio with prairie grass hay at equal DM intakes across treatments. The digestibility of DM and energy was greatest for W (p<.05) as compared to OW and O. No significant differences were detected in total tract apparent protein digestibility. Plasma glucose concentrations were highest in geldings fed W (p<.05) beginning 90 min post feeding and remained elevated out to 4 h indicative of the higher starch content of wheat. No palatability or health problems associated with feeding of wheat were noted. These data indicate that wheat can successfully be included in rations for horses.     

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.     

The effects of treated straw meal on ileal and faecal digestibility of nutrients in pigs

Four 40 kg castrated male pigs fitted with simple 'T' cannulas in the terminal ileum were given diets of varying crude fibre content in a change-over experiment with two periods. The basal diet was composed of wheat and fishmeal supplemented with minerals and vitamins. To this was added varying levels of partially hydrolysed straw meal to give crude fibre contents ranging from 40 to 132 g/kg. After adaptation to the particular levels of straw meal, faeces and ileal digesta were collected during successive 24 h periods. Nutrient digestibility values were determined by the chromic oxide ratio method. The addition of treated straw meal to the diet had little or no influence on the DM content of digesta or faeces. The excretion of N in faeces increased with increasing fibre intake but there was no effect on urine N excretion. The overall apparent digestibility of N was reduced from 89 to 79% as crude fibre intake increased from 40 to 132 g/kg but ileal apparent digestibility of N remained constant at about 68%, suggesting that the effect was mediated through hindgut bacteria. Increased fibre intake caused increased net secretion of Na in the small intestine and reduced the apparent absorption of P in the large intestine.