鹅和鸡4种常用饲料原料的代谢能比较

本试验旨在比较鹅和鸡常用饲料原料的代谢能差异.选用体重为(3.76±0.23)kg的成年扬州鹅(公)和体重为(2.57±0.17)kg的成年新扬州鸡(公)各10只,采用Sibbald真代谢能法测定玉米、豆粕、稻谷、麦麸4种常用饲料原料的代谢能值,内源能测定采用饥饿法.结果表明:玉米、豆粕的表观代谢能(AME)鹅与鸡差异不显著(P＞0.05),真代谢能(TME)鹅显著低于鸡(P＜0.05);而稻谷、麦麸的AME鹅显著高于鸡(P＜0.05),TME鹅与鸡差异不显著(P＞0.05).每小时内源能排出量,除强饲豆粕条件下鹅略高于鸡但差异不显著外(P＞0.05),强饲其他3种饲料条件下,鹅均显著高于鸡(P＜0.05).由此表明,鹅的饲料代谢能与鸡的并不完全相同,部分饲料的代谢能鹅和鸡之间存在显著差异,并且鹅的内源能排出量高于鸡.     

鹅对几种原料代谢能值的测定

本试验以24只175日龄扬州鹅公鹅为试验对象,用真代谢能(TME)测定法,测定了鹅对玉米、豆粕、小麦麸、稻谷、棉籽粕、苜蓿粉6种原料的代谢能值。试验结果表明:1)鹅对玉米、稻谷、小麦麸、豆粕、棉籽粕、苜蓿粉的表观代谢能(AME)值分别为12.23、10.93、8.03、8.99、6.67、4.25MJ/kg;真代谢能值分别为12.89、11.59、8.93、9.85、7.60、5.19MJ/kg。2)测得6种原料的TME值高于AME值,且TME∶AME为1.05～1.25;TME值的变异系数(CV)小于AME值,表明TME值的稳定性优于AME值。     

鹅饲用鸡肉骨粉的代谢能及常规营养成分代谢率研究

本文以鹅为试验动物,采用直接法和差量法研究鹅饲用鸡肉骨粉的营养价值.试验采用单因素完全随机设计,选取260日龄健康五龙鹅和青农灰鹅各42只(公),各设1个对照组和6个试验组,每组6个重复,试验鹅单笼饲养.对照组采用直接法,饲粮中不添加玉米淀粉;6个试验组采用差量法,分别在饲粮中添加15％、25％、45％、65％、75％、85％的玉米淀粉替代鸡肉骨粉.正试期3d,饲喂试验饲粮,然后排空24 h后,连续3d强饲无氮饲粮,每天强饲100 g,采用全收粪法.结果表明:1)五龙鹅和青农灰鹅品种内6个试验组的真代谢能(TME)及粗蛋白质(CP)、粗脂肪(EE)、部分氨基酸(AA)代谢率显著(P＜0.05)或极显著(P＜0.01)高于对照组;粗纤维(CF)、中性洗涤纤维(NDF)、酸性洗涤纤维(ADF)、钙(Ca)、磷(P)代谢率与对照组相比差异不显著(P＞0.05).2)差量法组间比较结果表明,75％玉米淀粉添加组五龙鹅和青农灰鹅的TME及CP、EE、部分AA代谢率均显著高于其他试验组(P＜0.05),85％玉米淀粉添加组的各项营养成分代谢率显著低于75％玉米淀粉添加组(P＜0.05).CF、NDF、ADF、Ca、P代谢率各组间差异不显著(P＞0.05).3)鸡肉骨粉对青农灰鹅TME及CP、部分AA代谢率显著(P＜0.05)或极显著(P＜0.01)高于五龙鹅;五龙鹅各组CF代谢率显著高于青农灰鹅(P＜0.05).试验表明,采用差量法测定鸡肉骨粉的鹅营养成分代谢率数据准确性较高,优于直接法,并且以75％玉米淀粉添加比例效果最好;鸡肉骨粉的鹅营养成分代谢率品种间存在一定的差异性.     

鹅代谢试验适宜强饲量的研究

本试验以20只成年扬州鹅为研究对象,按体重一致的原则随机分成强饲60、80、100g组和绝食对照组。采用绝食排空24h,排泄物收集24h的试验模式,测定了鹅对3种不同粗纤维含量饲料不同强饲量条件下的干物质利用率、能量利用率和代谢能值(表观代谢能和真代谢能)。结果表明,随着强饲量的增大,鹅对饲料干物质和能量的利用率逐渐升高,对饲料的代谢能值也有升高的趋势。强饲80g组与强饲100g组测得的饲料代谢能值无明显差异。表明用强饲法测定鹅饲料代谢能值时,适宜的强饲量为80~100g。     

生物秸秆对肉鸡表观代谢能的影响及替代玉米适宜比例的研究

本试验旨在研究肉鸡对生物秸秆的表观代谢能及其替代玉米的适宜比例.生物秸秆代谢能的测定试验选择24只42日龄健康的爱拔益加(AA)肉鸡,随机分为3个处理,每个处理8只鸡.处理1饲喂含8％生物秸秆的基础饲粮,处理2饲喂以30％的生物秸秆代替基础饲粮中能量饲料和蛋白质饲料的饲粮,处理3采用强饲法进行测定.生物秸秆代替玉米的试验选择150只42日龄健康的AA肉鸡,随机分为5个处理,每个处理5个重复,每个重复6只鸡.对照组饲喂基础饲粮,试验组分别在基础饲粮中用4％、8％、12％生物秸秆代替玉米(代谢能按照差量法计算结果12.46 MJ/kg计)及8％生物秸秆代替玉米(代谢能按照强饲法计算结果5.30 MJ/kg计,添加豆油,使其代谢能水平与对照组相同).结果表明:1)基础饲粮的代谢能为12.63 MJ/kg,采用差量法推算出肉鸡对生物秸秆的表观代谢能为12.46 MJ/kg,而采用套算法和强饲法测定生物秸秆的表观代谢能分别为4.38和5.30 MJ/kg.2)与对照组相比,4％和8％的生物秸秆代替玉米组中性洗涤纤维和酸性洗涤纤维的代谢率显著升高(P＜0.05),而12％的生物秸秆代替玉米组表观能量的代谢率显著降低(P＜0.05).由此得出,套算法和强饲法低估了生物秸秆的表观代谢能,而差量法更能准确反映生物秸秆的表观代谢能;在肉鸡饲粮中生物秸秆可以替代4％ ～8％的玉米.     

玉米胚芽粕对鹅营养价值的评定

为了探索玉米胚芽粕对鹅的营养价值和不同方法、不同鹅品种对其真代谢能、常规养分利用率的差异,分别选取150日龄健康五龙鹅和青农灰鹅公鹅各24只,各设4个处理组,每个处理组6只,试验鹅单笼饲养,每天强饲120 g,采用全收粪法进行测定.结果表明,五龙鹅、青农灰鹅种内4个处理组之间真代谢能(THE)、粗蛋白(CP)、粗脂肪(EE),A基酸(AA),中性洗涤纤维(NDF)、酸性洗涤纤维(ADF)、粗纤维(CF),it,(Ca),磷 (P)利用率差异均不显著(P>0.05).两品种之间,第2,4处理组青农灰鹅THE、CP真利用率显著(P<0.05)或极显著(P<0.01)高于五龙鹅;第3,4处理组青农灰鹅EE利用率显著(P<0.05)或极显著(P<0.01)高于五龙鹅.第1,3或4处理组五龙鹅NDF,CF利用率显著(P<0.05)高于青农灰鹅相应各处理组.由此可知,鹅对玉米胚芽粕的养分有较高的利用率;同品种不同处理下鹅对玉米胚芽粕的THE,常规养分利用率差异均不显著;不同品种鹅对玉米胚芽粕的养分利用率存在一定差异.     

无氮饲粮法与饥饿法对测定扬州鹅内源性氨基酸排泄量的影响

本试验旨在研究无氮饲粮法及饥饿法测定去盲肠鹅及正常鹅内源性氨基酸排泄量的差异。选用成年扬州鹅公鹅12只,随机分成2组,每组6只,对其中一组进行去盲肠手术,采用24 h禁食+24 h全收粪法进行试验。结果表明:无氮饲粮法测定的内源性氨基酸排泄量中,正常组的丝氨酸、亮氨酸、苯丙氨酸显著高于去盲肠组(P<0.05),去盲肠组的精氨酸极显著高于正常组(P<0.01),其余氨基酸差异均不显著(P>0.05)。饥饿法测定的内源性氨基酸排泄量中,正常组的天冬氨酸与缬氨酸显著高于去盲肠组(P<0.05),其余氨基酸差异均不显著(P>0.05)。由此表明,无氮饲粮法与饥饿法测定扬州鹅内源性氨基酸排泄量并不完全相同,大部分氨基酸之间存在极显著差异,饥饿法测定的多数内源性氨基酸排泄量低于无氮饲粮法。     

鹅对六种常见原料的代谢能值及部分营养成分利用研究

以24只成年扬州鹅公鹅为试验对象,用真代谢能测定法,测定了鹅对玉米、豆粕、麦麸、稻谷、苜蓿粉、棉粕6种原料的代谢能值和部分常规营养成分的利用率。试验结果表明:①鹅对玉米、豆粕、麦麸、稻谷、苜蓿粉、棉粕的AME值分别为12.23、8.99、8.03、10.93、4.25、6.67MJ/kg;TME值分别为12.89、9.85、8.93、11.59、5.19、7.60MJ/kg。②鹅对营养成分的利用率随原料和测定指标的不同而不同。对玉米、稻谷、麦麸营养成分的利用率和代谢能值比豆粕和棉粕高;对苜蓿粉的代谢能值最低。③鹅对6种原料的代谢能值和原料其它营养成分之间均呈负相关,其中与DM、ADF、Ash呈极显著负相关;原料各营养成分间,除GE、CP与NDF呈负相关外,其它营养成分间均呈正相关,其中ADF与DM的相关性最强;GE和CP的相关性较高,但和其它营养成分的相关性不高。     

产蛋期蛋鸡不同类型玉米净能研究

本试验利用禽用开放式呼吸测热装置进行能量代谢试验,通过间接测热法结合替代法测定不同类型玉米在产蛋期蛋鸡饲粮中的表观代谢能和净能。选用34周龄产蛋期海兰褐蛋鸡180只,随机分为6组,每组30只。试验选用1种玉米-豆粕型基础饲粮和5种待测饲粮。待测饲粮由5种待测玉米(3种2018年10月收获的正常玉米和2种2016年收获储存3年的陈化玉米),分别以50%比例替代基础饲粮构成。试验鸡在舍内笼养,预试期7 d,正试期27 d,其中正试期分为3期,每期9 d(适应3 d、呼吸测热3 d、绝食测热3 d)。每期试验中,从每组中选择4只试验鸡,称重后分别放入呼吸测热装置的12个代谢室(每个代谢室2只),每2个代谢室对应1种饲粮,测定气体交换和排泄物总量,呼吸测热的同时进行消化代谢试验。结果表明:与基础饲粮相比,5种玉米待测饲粮的表观代谢能显著提高(P<0.05),3种正常玉米待测饲粮的净能显著高于基础饲粮和2种陈化玉米待测饲粮(P<0.05);2种陈化玉米的表观代谢能和净能显著低于3种正常玉米(P<0.05)。本试验中,3种正常玉米的表观代谢能分别为16.19、15.85、16.17 MJ/kg,2种陈化玉米的表观代谢能分别为15.12和15.06 MJ/kg;3种正常玉米的净能分别为12.39、12.57、12.25 MJ/kg,2种陈化玉米的净能分别为11.29和12.05 MJ/kg。     

不同淀粉类型饲粮对育肥猪盲肠食糜主要微生物及其代谢产物的影响

本试验旨在研究不同淀粉类型饲粮对育肥猪盲肠食糜主要微生物及其代谢产物的影响。试验选取72头健康且初始体重相近的“杜×长×大”三元杂交阉公猪,随机分为3组,每组8个重复,每个重复3头猪。3组猪分别饲喂含有木薯淀粉、玉米淀粉和豌豆淀粉作为唯一淀粉来源配制的3种饲粮,饲粮的直链淀粉/支链淀粉分别为0.11、0.25和0.44。试验预试期4 d,正试期42 d。于正式试验的第42天,每个重复选取1头体重接近平均体重的猪进行屠宰,收集盲肠食糜进行相关指标的测定。结果表明:1)与木薯淀粉饲粮相比,豌豆淀粉饲粮显著降低育肥猪盲肠食糜的pH(P<0.05);2)与木薯淀粉饲粮相比,玉米淀粉和豌豆淀粉饲粮显著增加育肥猪盲肠食糜中乳酸的含量(P<0.05),同时豌豆淀粉饲粮显著增加食糜中乙酸、丁酸和总短链脂肪酸的含量(P<0.05);3)对于肠道微生物氮代谢产物而言,与木薯淀粉饲粮相比,玉米淀粉和豌豆淀粉饲粮显著降低育肥猪食糜中氨态氮、腐胺、总生物胺、吲哚和粪臭素的含量(P<0.05),同时豌豆淀粉饲粮显著降低食糜中尸胺和色胺的含量(P<0.05);4)对于微生物而言,与木薯淀粉饲粮相比,玉米淀粉和豌豆淀粉饲粮显著增加育肥猪盲肠食糜中普雷沃氏菌属的数量(P<0.05),而降低食糜中大肠杆菌的数量(P<0.05),同时豌豆淀粉饲粮增加了食糜中乳酸杆菌、双歧杆菌、梭菌Ⅳ和梭菌ⅩⅣ的数量(P<0.05)。由此可见,本试验条件下,给育肥猪饲喂含有高直链的豌豆淀粉改变了其盲肠食糜中微生物的组成和发酵模式,增加了部分有益菌的数量和碳水化合物代谢产物的含量,降低了潜在致病菌的数量和氮代谢产物的含量,这提示摄食含有高直链的淀粉有利于维持宿主肠道健康。     

Effect dietary corn starch intake on pancreatic amylase and intestinal maltase and pH in cattle

The pH optimum of pancreatic alpha-amylase from grain-fed steers was determined to be 6.9, while that of intestinal maltase was established at 5.8. Both assays were found to be linear up to 1 hr of incubation. The V max of pancreatic amylase was determined to be pancreatic amylase was determined to be 1.15 mg of maltose monohydrate produced/hr. Activities of pancreatic and intestinal maltase were not reduced (P greater than .05) during the interval from sample collection from the animal until analysis 4 hr later when tissues were kept on ice. Twenty-four yearling Holstein steers fed either alfalfa hay at a maintenance level of metabolizable energy (ME) intake or corn at one, two or three times the maintenance ME intake level were slaughtered after being fed 106 days. The pancreas was removed alone with sections of the intestine. Specific activity of pancreatic amylase for steers fed the high level of corn was 129% of that for steers fed the alfalfa diet (P greater than .05). Intestinal maltase activity was highest in the jejunum and decreased toward the ileum. Increasing dietary starch intake resulted in no response (P greater than .05) in maltase activity at 10, 30, 50, 70, or 90% of the small intestine length. The effect of dietary starch level on dieesta pH was dependent on sampling location within the small intestine. There were no dietary effects (P greater than .05) on digesta pH for the first 10% segment of intestine distal to the pylorus. However, in all subsequent sections, digesta pH was higher steers fed the alfalfa diet than for those fed the two higher levels of grain. A calculation for estimating th amount of pancreatic amylase needed to hydrolyze starch presented to small intestine is discussed.     

Influence of meal frequency on postprandial variations in the production and absorption of volatile fatty acids in the digestive tract of conscious pigs

Five Large White pigs of 62.2 +/- 1.4 kg mean body weight were fitted with permanent catheters in the portal vein and carotid artery and with an electromagnetic flow probe around the portal vein to study the absorption of volatile fatty acids (VFA) by measuring the concentration of these metabolites in hourly blood samples, and by determining the portal blood flow rate for a period of 12 h after intake of a single 800-g meal (6% crude fiber) preceded by 12 or 24 h of fasting. The portal concentration of VFA mixture always highly exceeded the arterial concentration. The arterial concentrations of propionic, butyric, valeric and isovaleric acids were nearly null, accounting for an almost complete uptake of these VFA by the liver. Acetic acid also was taken up, but to a lesser extent. Total VFA absorption during 12 h was 64% higher (P less than .05) after 12 h (1,160 +/- 100 mmol/12 h) than after 24 h of preprandial fasting (740 +/- 83 mmol/12 h). It increased after the meal (P less than .05) from 82.3 +/- 7.8 mmol/h between the first and fourth hour to 107.8 +/- 7.5 mmol/h between the fifth and tenth hour when the preprandial fasting lasted 12 h; a nonsignificant increase also was found when fasting prior to the meal lasted 24 h. The composition of the VFA mixture was not modified by the length of preprandial fasting. With this type of diet there was a large predominance of acetic acid (52%) followed by propionic and butyric acids (36 and 8.5%, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)     

Studies on nitrogen metabolism in the large intestine of ruminants. 5. Metabolism of intra-cecally infused 15N-urea without and with fermentable material in heifers

Six heifers with a live weight of 215, 227 and 238 kg (experiment 1) and 220, 227 and 233 kg, resp. (experiment 2), were supplied with ileocaecal re-entrance cannulae, jugular venous catheters and bladder catheters. The ration consisted of 4 kg maize silage and 4 kg wheat straw pellets per animal per day. Up to 3.5 kg of the straw pellets, consisting of 73% wheat straw, 10% barley, 12% molasses, NPN salts and a mineral mixture, were consumed per animal per day. In a preliminary period 50% of the digesta flow was collected over 12 h/d on 5 consecutive days and stored in a deep-freeze. During the main trial the re-entrance cannula was disrupted and the flowing digesta were quantitatively collected at the end of the ileum; previously collected digesta were supplemented with 15N urea and every hour over 24 h infused into the caecal part of the re-entrance cannula. Between the 24th and 30th hours the digesta were infused without 15N urea supplement. In trial 2 the digesta were also supplemented with partly hydrolysed straw meal between the 1st and 30th hours (approximately 10% straw meal DM related to digesta DM). There were no differences between trials 1 and 2 with regard to the increase of atom-% 15N excess (15N') in the plasma urea. The 15N labelling decrease of the plasma urea N shows that the half-life is 7.9 h in trial 1 and 7.0 h in trial 2. The NH3 nitrogen in faeces was distinctly higher labelled in trial 2 after the supplement of straw meal than in trial 1. The total N in faeces was also twice as highly labelled as in trial 1. Atom-% 15N' in urine was significantly higher in trial 2 than in trial 1 between the 6th and 16th hours after the beginning of 15N urea supplementation. In the decrease curve of atom-% 15N' (after the 26th hour of trial) the values in trial 1 were generally higher than in trial 2. The higher bacterial protein synthesis in the large intestine in trial 2 (after the supplement of partly hydrolysed straw meal) had the effect that 13.6% of the supplemented 15N' was excreted in faeces by the 30th hour of trial, in contrast to this only 4.7% in group 1. Up to the 4th day after the 15N urea infusion these values increased to 16.2 and 6.1%, resp., only.     

Effects of dietary fat and triamcinolone additions during late gestation on the body energy reserves of neonatal pigs

Two trials involving 21 primiparous sows were conducted to evaluate the effects of fat and triamcinolone additions to the diet of late-term, gravid sows on carbohydrate, protein and fat reserves in nursed and fasted neonatal pigs. Beginning 7 d prepartum, sows were fed daily 1.8 kg (6 Mcal metabolizable energy, ME) of a fortified, corn-soybean meal diet that was supplemented with 4 Mcal ME/sow in the form of starch, soybean oil or soybean oil plus 70 mg/sow of triamcinolone, a synthetic glucocorticoid. After parturition, the sows were fed daily 5 kg (15 Mcal ME) of a 14% protein, corn-soybean meal diet. The addition of soybean oil to the diet of sows during late gestation did not influence (P greater than .1) liver glycogen content, serum glucose levels or carcass protein and fat reserves in nursed or fasted pigs from birth to 6, 12, 24 or 48 h of age. The addition of triamcinolone to the sows' prepartum diet increased (P less than .1) fat deposition in the nursed pigs from birth to 48 h of age. Liver glycogen reached minimal levels by 24 h postpartum in both nursed and fasted pigs, regardless of the sows' prepartum treatment. Serum glucose levels were maintained at 80 to 130 mg/dl in the nursed pigs from birth to 48 h of age, but approached hypoglycemic levels (50 mg/dl) by 24 h in the fasted pigs. Nursed pigs deposited 28 g of body protein and 15 g of fat from birth to 48 h of age; whereas, fasted pigs mobilized only minimal quantities (3 g) of body protein and fat.     

Associations between meal size,gastric emptying and post‐prandial plasma glucose,insulin and lactate concentrations in meal‐fed cats

Plasma glucose and insulin concentrations are increased for 12–24 h in healthy cats following moderate‐ to high‐carbohydrate meals. This study investigated associations between gastric emptying time and post‐prandial plasma glucose, insulin and lactate concentrations in cats fed an extruded dry, high‐carbohydrate, moderate‐fat, low‐protein diet (51, 28, 21% metabolizable energy, respectively) once daily by varying meal volume. Eleven healthy, non‐obese, neutered adult cats were enrolled in a prospective study and fed to maintain body weight. Ultrasound examinations were performed for up to 26 h, and blood collections over 24 h after eating meals containing approximately 100% and 50% of the cats’ daily caloric intake (209 and 105 kJ/kg BW, respectively). Gastric emptying time was increased after a meal of 209 kJ/kg BW compared with 105 kJ/kg BW (median gastric emptying times 24 and 14 h, respectively; p = 0.03). Time for glucose to return to fasting was longer after the 209 kJ/kg BW meal (median 20 h; 25th and 75th percentiles 15 and 23 h, respectively) than the 105 kJ/kg BW meal (13, 12 and 14 h; p < 0.01); however, peak glucose was not higher after the 209 kJ/kg BW meal compared with the 105 kJ/kg BW meal [(mean ± SD) 6.6 ± 0.6 and 7.8 ± 1.2 mmol/l, respectively, p = 0.07]. Times for insulin to return to fasting were not significantly longer after the 209 kJ/kg BW meal than the 105 kJ/kg BW meal (p = 0.29). d ‐ and l ‐lactate concentrations were not associated with gastric emptying time or post‐prandial blood glucose and insulin. Based on results obtained, prolonged gastric emptying contributes to prolonged post‐prandial hyperglycemia in cats meal fed a high‐carbohydrate, low‐protein, dry diet and fasting times for cats’ meal‐fed diets of similar composition should be 14–26 h, depending on meal size.     

The effects of different sources of nitrogen supplementation on the post ruminal flows of organic matter and different nitrogenous constituents in steers

Friesian steers, virtually protozoa free, were equipped with simple rumen and abomasal cannulas. They were given diets consisting of approximately equal proportions of ground, pelleted alkali treated straw and a rolled barley, tapioca mixture supplemented with urea + casein (UC), soybean meal (SBM), 'normal' white fishmeal (NDF) or white fishmeal designated as being of 'low' rumen degradability (LDF). The diets were isoenergetic (the protein sources replacing part of the tapioca) and they were given in amounts to supply sufficient metabolizable energy (ME) to support an average growth rate of 0.5 kg/d. Rumen degradable nitrogen (RDN): ME values were estimated to be 2.08, 1.40, 1.90 and 1.66 for diets UC, SBM, NDF and LDF respectively. RNA, alpha-epsilon-diaminopimelic acid and 35S (added as sulphate) were used as bacterial markers. Chromic oxide and polyethylene glycol (PEG) were given as flow markers and flows (g/24 h) at the abomasum of organic matter (OM) and nitrogenous constituents were calculated. Rumen volumes and ruminal liquid fractional outflow rates were measured using PEG. Samples of mixed rumen bacteria separated from strained rumen digesta from animals receiving diet UC contained significantly less DAP-N (0.322 g/kg DM) than those from animals receiving diets SBM, NDF or LDF (0.530 g/kg DM). Mean rumen volume (approximately 15 l) and liquid fractional outflow rates (approximately 0.105/h) were similar on all diets but there was appreciable variation between animals. The proportion of OM intake digested in the rumen was similar on all diets. The proportional contribution of bacterial-N to the total non-ammonia-N passing the abomasum based on mean values derived from DAP and 35S as markers was 0.57, 0.47, 0.39 and 0.31 for diets UC, SBM, NDF and LDF respectively. Corresponding values based on RNA were 0.71, 0.50, 0.48 and 0.35 respectively. Bacterial-N (RNA) flows at the abomasum were 31, 25, 26 and 20 g/d for diets UC, SBM, NDF and LDF respectively. Corresponding values for 35S and DAP were 26, 24, 21 and 18 g/d respectively. Values derived from RNA flows were consistently and significantly higher (P less than 0.01) than those based on DAP or 35S. Mean estimated efficiencies of bacterial protein synthesis (g bacterial-N/kg OM truly digested) were 15, 15, 14 and 12 for diets UC, SBM, NDF and LDF respectively.(ABSTRACT TRUNCATED AT 400 WORDS)     

Metabolizable and Net Energy Values of Expanded Cottonseed Meal for Laying Hens and Broiler Chickens

Three experiments were conducted to determine the metabolizable energy (ME) and net energy (NE) values of expanded cottonseed meal (ECSM) for broilers aged 14–16 days (Experiment 1), broilers aged 28–30 days (Experiment 2), and 45-week-old Hy-Line Brown hens (Experiment 3). Reference diets based on corn-soybean meal were used to meet the nutritional needs of the birds. The test diets contained ECSM as basis, which was used to replace 18.5% of the gross energy-yielding ingredients from the reference diet. The birds were fed a commercial feed before the experimental period. After the dietary adaptation period, six birds per replicate (Experiment 1) and two birds per replicate (Experiments 2 and 3) for each treatment group were placed in an individual open-circuit respiratory calorimetry chamber for 3 days. Daily O₂ consumption and CO₂ production were recorded, and excreta samples were collected. The ME and NE values of ECSM were determined using the substitution method. The apparent metabolizable energy (AME) values of ECSM for experiments 1, 2, and 3 were 2605.85, 2178.31, and 2782.60 kcal/kg of dry matter (DM), respectively. The NE values were 1655.23, 1196.64, and 1538.19 kcal/kg of DM, respectively. The NE:AME ratios of ECSM were 63.52%, 54.93%, and 55.29%, respectively. Our data showed that the ME and NE values of ECSM differed across various growth stages and types of chickens. These results demonstrate that the appropriate ME and NE should be used in the design of different feed formulas for specific growth stages and types of chickens.     

The effect of pre-fast diet and transport on nitrogen metabolism of calves

Two trials were conducted to determine the effects of transport stress and pre-transport diet on N losses, blood chemistry and ruminal variables of steers. In each trial, 16 crossbred steers (261 kg avg weight) were assigned to four groups in a 2 X 2 factorial arrangement of treatments. Treatments consisted of either transported or non-transported groups and two pre-transport dietary regimens (alfalfa hay or a 50% concentrate diet fed for 3 d before fasting). The alfalfa hay contained 14.6% crude protein (CP) and had a calculated metabolizable energy (ME) content of 1.92 mcal/kg. The 50% concentrate diet contained 15.5% CP and had a calculated ME content of 2.23 mcal/kg. Steers in the transport group were transported for 13 h in trial 1 and 46 h in trial 2, while the remaining steers were not transported. Both groups were withheld from feed and water during the observation periods. Urine and feces were collected and blood samples were obtained at intervals during the observation periods. Transport increased (P less than .05) urinary and total N excretion and nonevaporative water losses compared with fasting alone. Calves fed the 50% concentrate diet had lower N and nonevaporative water losses than calves fed hay, probably due to lower pre-fast N and water intakes. Ruminal total volatile fatty acid (VFA) concentrations and molar proportions of propionate and butyrate declined (P less than .05) with time in all groups, while molar proportions of acetate and minor VFA increased. Results of these trials indicate transportation stress can cause a significant increase in total N excretion and nonevaporative water loss compared with feed and water deprivation alone. Losses of N and water were lower in calves fed a 50% concentrate diet rather than hay for 3 d before the fasting period, probably because of lower pre-fast N and water intakes.     

鸭饲料表观代谢能和真代谢能值测定

选用80只成年北京公鸭,测定了进口鱼粉、鸭肠粉、鸭血粉、皮革粉、鸭毛粉、玉米蛋白粉、黄豆、豌豆、玉米胚芽粕、棉粕、高粱酒糟、葵花饼、芝麻粕、高粱、大麦、稻谷、次粉、米糠共计18种饲料原料的表观代谢能(AME)和真代谢能(TME),排空、收集期为36h,强饲量为50g。