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The effect of monensin (33 mg/kg) and no monensin on distribution of ammonia and free amino acids in fluid and particulate phases of ruminal contents was studied. Two Jersey cows and two Angus-Hereford steers, weighing approximately 350 kg and each containing a ruminal cannula were meal fed a 65% concentrate diet for two periods. Feed was available for 30 min; any feed not eaten was removed after this time. Whole ruminal contents were sampled before feeding, immediately after feed removal and 1, 2, 3, 4, 6, 8, 10 and 12 h after feed removal. A crossover design with split-plot in time was used with four observations per time point per treatment. Extracellular (E) ammonia and amino acids were determined on high speed supernatants of strained ruminal fluid. Total (T) ammonia and amino acids were obtained by lysing microbial cells with 1% cetyltrimethylammonium bromide (CTAB) and one freeze treatment before centrifugation. Intracellular (I) amino acids and ammonia were determined as T minus E. Squeezed particles were suspended in .1 N HCl containing 1% CTAB. Total and E ammonia were higher throughout the study for no monensin vs monensin (P less than .05). Intracellular ammonia was low (.03 to 1 mM) and did not change (P greater than .10) across time for either dietary treatment. Intracellular amino acids ranged from 1.2 to 4.5 mM and were higher (P less than .05) than E amino acids (.9 to 2.2 mM) for both diets immediately after feeding. Monensin did not significantly lower (P greater than .10) T amino acids compared with no monensin throughout sampling (2.6 and 3.1 mM, respectively).(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
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The possibility of free amino acid (FAA) and peptide absorption across the ruminant stomach wall was studied in multicatheterized wethers fed every 12 h. During the last third of the feeding cycle, two intraruminal or intraomasal injections of solutions containing increasing amounts of Ser, Gly, Val, Met, Phe, Lys, and carnosine were successively performed. Before injections, a net uptake of each of these FAA was measured in the ruminal and the gastric veins. The ruminal injections produced a linear increase in ruminal FAA concentration. The highest ruminal concentrations (observed with 3 g of FAA and carnosine) ranged between 5 and 14 mM. After ruminal injections, Ser (P < .05), Gly (P < .05), Val (P < .05), Met (P < .10), and Lys (P < .10) uptake decreased and carnosine net release linearly increased (P < .05), suggesting absorption across the ruminal epithelium. Owing to the low net flux generated by high ruminal concentration, the ruminal epithelium permeability to these molecules seemed to be low. After omasal injections, net flux of injected FAA were not modified, suggesting a low permeability of the gastric epithelia to FAA. Carnosine net release linearily increased (P < .05) with increasing level of carnosine injection, indicating the possibility of dipeptide absorption at the gastric level. This study demonstrated in vivo that the stomach epithelia possess the capacity to absorb FAA and small peptides; however, the permeability of these epithelia to these molecules seemed limited. 相似文献
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Biosynthesis of amono acids by ruminal microorganisms 总被引：13，自引：0，他引：13
M J Allison 《Journal of animal science》1969,29(5):797-807
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The objective of this study was to examine the effects of Aspergillus oryzae fermentation extract (Amaferm) on the in vitro ruminal fermentation of coastal bermudagrass, soluble starch and amino acids. Mixed ruminal microorganisms were incubated in anaerobic media for either 24 h (Amaferm alone, soluble starch, amino acids) or 48 h (bermudagrass). Amaferm was added to the incubation bottles (n = 4) at concentrations of 0, .4 or 1.0 g/liter. When mixed ruminal microorganisms were incubated with only Amaferm, the 1.0 g/liter concentration increased the production of hydrogen (H2; P less than .001), methane (CH4; P less than .01), acetate (P less than .05), butyrate (P less than .01), total VFA (P less than .05) and NH3 (P less than .05). Addition of both levels of Amaferm to soluble-starch fermentations tended to enhance the production of H2 (P less than .11), CH4 (P less than .15), acetate (P less than .29) and total VFA (P less than .19); propionate production was increased (P less than .10) by 1.0 g/liter Amaferm, resulting in a decrease (P less than .05) in the acetate:propionate ratio. Fermentation of amino acids plus 1.0 g/liter Amaferm enhanced the production of acetate (P less than .05), propionate (P less than .05), valerate (P less than .01) and total VFA (P less than .10) and decreased the acetate:propionate ratio (P less than .05). In addition, NH3 production tended (P less than .19) to increase with both levels of Amaferm. When bermudagrass was the substrate, few changes in fermentation products were observed with Amaferm treatment.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
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关于乳猪的蛋白质需要量及氨基酸需要模式,研究很多,争议也很多。本文就目前一些研究成果进行综述,希望能够抛砖引玉,为乳猪理想氨基酸模型的建立提供依据。1关于乳猪理想蛋白质模式猪整个生长期所需的最佳氨基酸平衡只有一个。通常认为,不同体重或日龄的生长猪躯体或肌肉的氨基酸比例相当稳定,理由如下(:1)维持需要占总需要的比例很小(3%￣6%),生长猪对氨基酸平衡的要求主要由生长决定(;2)不同性别或体重的生长猪,驱体氨基酸比例恒定,氨基酸需要量的差异仅是绝对量的差异(;3)生物学活性高的蛋白质,氨基酸比例与肌肉相似(;4)氨基酸需要量的… 相似文献
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本文采用过甲酸氧化水解法处理饲料及饲料原料样品、通过日立L-8900氨基酸自动分析仪检测样品中的含硫氨基酸含量,结果显示：每份试样平行测试结果相对偏差小于4％．蛋氨酸和胱氨酸峰面积回收率在93．02％～102．06％．该方法测定含硫氨基酸的重复性和准确性良好．氧化水解法比常规盐酸水解法处理样品检测含硫氨基酸．检测结果更为准确。 相似文献
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氨基酸是构成蛋白质的基本单位，参与机体的生化反应和生理机能过程，是动物最重要的一类营养物质。目前已经发现的氨基酸有25种以上，构成动物蛋白质的氨基酸有20种左右。这些氨基酸又分为两类：一类是动物体内不能合成，或合成量很少，不能满足动物机体正常的需求，需要从饲料中摄入的氨基酸，叫做必需氨 相似文献
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文章采用酸解法-氨基酸分析仪测定蚕蛹中17种氨基酸含量。该法预处理过程简单,17种氨基酸在65 min内完全分离。此法简便、快捷、重复性好,灵敏度高。 相似文献
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Effect of the ratio between essential and nonessential amino acids in the diet on utilization of nitrogen and amino acids by growing pigs. 总被引：5，自引：0，他引：5
N P Lenis H T van Diepen P Bikker A W Jongbloed J van der Meulen 《Journal of animal science》1999,77(7):1777-1787
In 36 growing pigs (30 to 60 kg), N balance and amino acid (AA) composition of weight gain were measured to evaluate the interactive effect of the ratio between N from essential amino acids (EAA(N)) to nonessential amino acids (NEAA(N)) and total N level (T(N)) in the diet on N retention and utilization of N, EAA(N), NEAA(N), and AA. Nine diets composed from ordinary feedstuffs and supplemented with crystalline AA were used (three EAA(N):NEAA(N) ratios of 38:62, 50:50, and 62:38 at three T(N) levels of 18.8, 22.9, and 30.0 g/kg). Pigs were fed restrictedly, at a level of 2.8 x energy for maintenance. In all diets, EAA (including arginine) supply was according to or slightly above the recommended ratios to lysine. Measurements were done in four blocks of nine pigs each. In a concomitant slaughter experiment, the AA composition of deposited body protein was determined to estimate AA utilization. The effects of T(N) and EAA(N):NEAA(N) and their interaction for N retention and utilization were significant. Nitrogen retention increased with higher T(N) in the diet. Increasing EAA(N):NEAA(N) from 38:62 to 50:50 improved N retention only at the two lower T(N) levels. Increasing EAA(N): NEAA(N) above 50:50 failed to improve N retention significantly at any of the three T(N) levels. Lowering T(N) improved the utilization of total and digested N and of EAA(N) and NEAA(N). The increase in EAA(N): NEAA(N) consistently resulted in a lower utilization of EAA(N), but this was compensated by a higher utilization of NEAA(N). The utilization of T(N) was improved by increasing EAA(N):NEAA(N) from 38:62 to 50:50 at the two lower T(N) levels and was relatively unaffected by EAA(N):NEAA(N) at the highest T(N). However, a lower utilization of N was observed at a ratio of 62:38 at a T(N) level of 22.9 g/kg. The effects were similar for utilization of individual EAA and NEAA. Utilization of alanine, aspartic acid, and glycine was close to or >100% at the highest EAA(N):NEAA(N), which was expected because all of these AA are synthesized in pigs. Also, the utilization of arginine was >100% in most of the treatments, which confirms the semiessential character of this AA for maintenance. We concluded that the required ratio of EAA(N):NEAA(N) for optimal N retention and utilization is approximately 50:50. The EAA(N):NEAA(N) is more important at lower dietary protein levels. This study indicates that EAA(N): NEAA(N) can be increased up to 70:30 without lowering the utilization of N. Thus, deaminated EAA(N) was efficiently utilized for the synthesis of NEAA(N). 相似文献