The dynamics of the content of ammonia and volatile fatty acids in the rumen fluid during the use of dry feed rations in the cow

The development of the pH-value, the molar quota of volatile fatty acids and of the NH3 content in the change from silage rations to dried rations on the basis of pelleted feed and in dependence on the time after the beginning of feeding was tested in studies of the rumen fluid of four cows in order to explain the causes of the very low NH3 content of the rumen fluid in feeding experiments with rations based on pelleted straw-concentrate mixtures. An influence of the ration type and the time after the beginning of feeding on the molar quota of the individual volatile fatty acids and the NH3 content was ascertained. The ration type tested can cause an NH3 content in the rumen fluid below 1 mmol/l.     

The effect of Rumensin on the metabolic profile of rumen fluid in feedlot cattle

The effects were studied of sodium monensinate dosed 125 mg on the metabolic profile of rumen fluid. The experiment was conducted under current farming conditions in a pavilion cattle fattening house. The experiment, which lasted 367 days, comprised 985 bulls of the Bohemian Spotted breed. The feed ration was based on silage with an additive of dried poultry litter and concentrates. The additive was administered in concentrate mixture, 125 mg per head/day. After the start of the experiment want of appetite to sodium monensinate was observed. The animals took approximately four weeks to adapt completely to the additive. The following characteristics were investigated to study the metabolic profile of rumen fluid: actual acidity, total titration acidity, ammonia, total nitrogen, lactic acid, total volatile fatty acids, per cent acetic acid, per cent propionic acid, molar ratio acetic acid: propionic acid, per cent iso- and n-butyric acid, absolute number of infusoria and energy net yield of volatile fatty acids. Increased levels of the clinico-biochemical parameters of the metabolic profile of rumen fluid were found in lactic acid, propionic acid and energy net yield of volatile fatty acids. The per cent of propionic acid increased at some samplings by up to 116%. A drop was recorded in total nitrogen, per cent acetic acid, per cent butyric acid, molar ratio C2 : C3 and total number of infusoria. The decrease in the per cent of acetic acid ranged around 16% and the drop in butyric acid level amounted at some samplings up to 78%. No response to the additive was observed in the other characteristics of the metabolic profile of rumen fluid.     

颗粒日粮中添加柠条对滩羊生长性能、血液生化指标、瘤胃发酵及羊肉品质的影响

[目的]研究颗粒日粮中添加柠条对滩羊生长性能、血液生化指标、瘤胃发酵及羊肉品质的影响。[方法]选择体重相近的健康去势滩羊20只,随机分成两组,每组10只;对照组饲喂含有10%菊花粕的颗粒日粮,试验组饲喂含有6%柠条和4%菊花粕的颗粒日粮;开展周期为50天的育肥试验,测定滩羊的生长性能指标;育肥试验结束后,测定滩羊血液生化指标;屠宰后测定滩羊的屠宰性能指标,并取瘤胃液测定瘤胃发酵指标;取背腰最长肌,测定粗脂肪、粗蛋白、氨基酸含量以及脂肪酸组成。[结果]试验组和对照组滩羊的初始体重和终末体重无显著（P>0.05）差异;试验组平均日增重较对照组降低10.84%,差异不显著（P>0.05）;对照组平均日采食量显著（P<0.05）高于试验组;两组试验羊料肉比相同。试验组滩羊血清中的总蛋白含量显著（P<0.05）高于对照组,其他血液生化指标无显著（P>0.05）差异。对照组滩羊屠宰率比试验组高1.59%,差异不显著（P>0.05）;两组试验羊肝脏重、肝脏指数、心脏和肺脏重、心脏和肺脏指数差异不显著（P>0.05）。试验组滩羊瘤胃液中丁酸浓度显著（P<0.05）高于对照组,异戊酸浓度显著（P<0.05）低于对照组。对照组和试验组滩羊背腰最长肌中分别检测出18种和20种脂肪酸,粗蛋白含量分别为17.51%和20.92%,粗脂肪含量分别为3.22%和3.89%,总氨基酸含量分别为13.25%和14.09%。[结论]颗粒日粮中加入柠条对滩羊生长性能、血液生化指标和屠宰性能影响不明显,但可改善瘤胃发酵,丰富羊肉中脂肪酸组成及含量,增加肉中粗蛋白、粗脂肪和氨基酸含量。     

The effect of monensin on the fermentation of feed with different proportions of hay and concentrate in an artificial rumen (rumen simulation technic)

An experiment was conducted with rumen pouch (RUSITEC--Rumen Simulation Technique). In four fermentation vessels (V), percent proportions of hay and barley were as follows: V1--40:60, V2 - 60:40, V3--80:20 and V4--100:0. Every day 5 mg of monensin dissolved in 1 ml 96% ethanol were added to each fermentation vessel. All diets were isonitrogenous, and after an addition of urea the crude protein (CP) content made 13% in each diet. The experiment lasted 12 days: so called steady state period took the first six days when the fermentation conditions were stabilized. Monensin reduced dry matter digestibility, production of total volatile fatty acids, acetic acid, n-butyric and isovaleric acids and acetate: propionate proportion, and it increased the production of propionic and n-valeric acids. The production of methane and CO2 decreased. The higher proportion of hay in diets decreased dry matter digestibility, digestibility of detergent fibre, total and individual volatile fatty acids, CO2, methane energy yield of volatile fatty acids (E), glucose utilization, production of adenosine triphosphate and production of fermented hexoses. The production, utilization and recovery of metabolic hydrogen also decreased. The effectiveness of microbial matter synthesis (YATP = 11.3) was highest during the fermentation of feed containing 60% hay and 40% barley.     

The influence of folic acid, vitamins B(2) and B(6) supplementation on feed intake, body and organs weight, and liver fatty acids composition of rats subjected to 3 months moderate protein deprivation

This study was conducted to determine the effect of a 3-month dietary protein restriction - protein provided 9% of energy (20% in control group). In this dietary restriction folic acid, vitamins B(2) and B(6) were delivered in amount three times above the standard level. It was observed that animals fed a protein restricted (PR) diet weighed about 5% less than animals consuming adequate diet, but the difference was not statistically significant. Enrichment of PR diet with vitamin B or folic acid caused tendency to further suppression of weight gain, and in case of vitamin B(6) these differences were statistically significant. However, such body weight (BW) suppression was not observed when all studied vitamins were used together. Significant reductions in relative liver weight (vitamin B(2) addition), the heart (folic acid) and the lungs (vitamin B(6)) were observed. The PR diet, when all vitamins were added together, caused a decrease in weights of the lungs, heart and liver scaled to BW of rats, simultaneously with a significant increase in testis weight. Feed intake and feed conversion ratio were higher in animals given PR diet without a significant influence of vitamin supplementation (except vitamin B(6) causing further increase in feed conversion ratio). Hepatic fatty acids composition of rats was not affected by protein restriction, as well as by single vitamin supplementation. However, dietary supplementation of all examined vitamins together caused a decrease in monounsaturated fatty acids followed by an increase in polyunsaturated fatty acids participation in total fatty acids pool. It seems that enrichment of PR diet with a mixture of folic acid, vitamins B(2) and B(6) resulted in a partial reverse of growth suppression and reduction in testis size in rats.     

Influence of folic acid, vitamin B2 and B6 supplementation on feed intake, body and organs weight, and liver fatty acids composition in rats subjected to severe protein deprivation

Growing rats fed for 3 months a low-protein (LP) diet (4.5% of energy from protein), possessed about 29% lower body weight than animals consuming adequate-protein diet (20% energy from protein). The LP diet feeding caused an increase in daily feed intake followed by a decrease in feed conversion efficiency. The enrichment of LP diet with folic acid, vitamin B2 and B6 (3 times above the level applied in the control diet) did not have any impact on rats BW and supplementation with these vitamins minimize the effect of LP diet on feed intake. The use of examined vitamins had a tendency to diminish an increase in feed conversion ratio caused by the LP nutrition. This effect was significant when all vitamins were added together. Rats fed the LP diet had higher relative weights of lungs, heart, liver and testis. Vitamins enriching the LP diet were observed to decrease a relative weight of lungs (folic acid, vitamin B6 and vitamin mixture), and liver (vitamin B6 and vitamin mixture). A tendency of increasing relative testis weight was also revealed in rats given the LP diet enriched with vitamins. The lower content of hepatic polyunsaturated fatty acids (FA) and a tendency for monounsaturated FA content to be higher were found in rats fed the LP diet. The LP diet enrichment with folic acid caused that these changes were more pronounced and statistically significant. Enrichment of LP diet with vitamins tested may cause a partial reverse of changes observed in the hepatic FA composition.     

The relationship between fermentation and the morphological structure of rumen epithelium in sheep fed pelleted feeds]

Wethers were fed complete granular feed rations including 41.81% of grass hay, 25.28% of barley, 15.37% of sawdust, 14.98% of molasses, 1.32% of urea, and 1.24% of mineral supplement in dry matter for 24 weeks. Samples of the dorsal rumen sac of these wethers were subjected to patho-anatomical, histological, histo-chemical, and electron-microscopical examination. Volatile fatty acids were also determined in the rumen fluid of slaughtered animals. The control group was given the same diet in the classical form with long hay. The rumen contents of the slaughtered animals of the experimental group had an increased level of total volatile fatty acids (125.93 mM) and butyric acid (17.8 M%). The acetate:propionate ratio was 3.66. No substantial differences were observed in enzymatic activity. Electronograms recorded an increase in the number of T cells and keratinizing cells -- this suggests an increased intensity of the process of keratinization.     

Water intake, pH and ammonia levels in the ruminal contents of sheep fed pelleted feed]

Wethers were studied for the effect of the complete pelleted feed ration on the intake of water and concentration of pH and ammonia in the rumen. The animals consumed daily 1300 g of dry matter of the diet containing 41.81% of meadow hay, 25.8% of barley, 15.37% of sawdust, 14.98% of molasses, 1.32% of urea and 1.24% of vitamin mineral supplement. This feed was given to them for six months. The pelleted diet increased the intake of water (the dry matter consumption remaining the same in the control and experimental group), reduced pH concentration (6.0--6.2) and slightly increased the level of ammonia in the first hour after feeding; this was probably due to a rapid release of nitrogen compounds from the feed and to intensive rumen fermentation.     

The effect of straw in ground and pelleted form on the rumen fermentation and protozoa]

Cows possessing a large ruminal fistula were fed straw meal and pelleted wheat straw to investigate its effect on ruminal fermentation (concentration of NH3 and volatile fatty acids (FFS), pH, molar proportions of FFS, rates of FFS production) and on the protozoa population. The straw-concentrate mixture used in the present trial contained 40% of straw. The feeding of pelleted straw produced a significant rise in FFS concentrations (from 8.8. to 12.3 mMole/100 ml) and a corresponding decline of pH (from 6.7 to 6.1). With high molar proportions of acetate (72 mole%) the influence of the straw diet on molar FFS proportions was low. The NH3 peak observed 1 hr after feeding was higher with the pelleted straw than with the straw meal. The feeding of finely gound straw produced a higher level of FFS production (by 10%) than that of straw pellets. (3.88 and 4.29 mMole per gm DM). The number of protozoa (per ml of ruminal fluid) was 335,000 (straw meal) and 121,833 (pellets). The number of large infusorial cells (Isotricha, Diplodinium, Ophryoscolex) decreased correspondingly from 70,000 (straw meal) to 18,870 per ml (pellets). These results suggest that the feeding of pelleted straw-concentrate mixtures to cows as sole feed will not bring about optimum conditions for ruminal fermentation (FFS formation, protein synthesis) and for the layering of ruminal contents.     

Feeding organic acids enhances the barrier function against pathogenic bacteria of the piglet stomach

The effect of coarsely ground meal feed versus finely ground heat-treated pelleted feed and the addition of lactic acid and formic acid in combination on the physico-chemical properties, microbial composition and concentration of organic acids in the stomach content of piglets was investigated. A total of 60 weaned piglets were included in a 2 × 2 factorial arrangement in 15 randomised complete blocks. After three weeks, the pigs were put down and samples of digesta from the gastrointestinal tract were analysed for dry matter (DM), pH, organic acids and microbiological enumeration. Feeding coarsely ground meal feed increased the DM percentage, the concentration of organic acids and pH in the proximal stomach and lowered the distal stomach pH compared with finely ground heat-treated pelleted feed. However, the addition of organic acids to the diets lowered the pH in the stomach and was able to reduce the population of enterobacteria in the stomach.     

Research Progress on Influence Factors of Mutton Flavor

The flavor of mutton affects the acceptance of consumers.Adipose tissue is the most obvious source of mutton flavor, and the compounds presenting mutton flavor mainly include branched chain fatty acids, aldehyde compounds, phenolic compounds, ketone substance and so on.Mutton flavor is affected by genetic factors such as breed, sex, age, nutrition factors such as the nutrient level of diet and additive, feeding model and disease, etc.The effect of breed on the flavor may be achieved by the genetic control on fat composition and metabolism, and the amount of fat oxidation products is the main reason for different flavor among species.There are differences in fatty content and composition because of different sex, and it also has an effect on the flavor of mutton.Along with the growth of sheep, the deposits of subcutaneous fat, the proportion of saturated fatty acid, and the concentration of the lipid oxide increase, all these led to strong flavor of the lamb.Each parts of the lamb has different flavor because of the differences kind and content of the volatile compounds.The types of diet have a certain influence on mutton flavor, such as high protein feed, high energy feed, flavor plant, seeds with high content of unsaturated fatty acid and other additives.Feeding mode and disease factor also can make a change of mutton flavor.Other factors, such as the feeding density, illumination and so on, also have effects on the flavor of mutton in varying degrees.The flavor of mutton can be improved through breed selection, nutrition regulation and scientific feeding and management during sheep production.     

影响羊肉风味的因素研究进展

羊肉的风味在一定程度上影响消费者的接受度,因此对羊肉风味的研究备受关注。脂肪组织是羊肉最明显的风味来源,而呈现羊肉风味的化合物主要有支链脂肪酸、醛类化合物、酚类化合物及酮类物质等。品种、性别和年龄等遗传因素、饲料营养水平及各种添加物质等营养因素、饲养方式及疾病等因素均可影响羊肉风味。脂肪组成和代谢的遗传控制可以形成品种特有的风味,而脂肪氧化产物碳酰化合物种类和数量的差异是种间风味差异的主要原因。性别不同在脂肪含量及组成上存在差异,对羊肉风味也有影响。随着动物年龄的增长,皮下脂肪沉积增多,饱和脂肪酸比例增大,脂质氧化物的浓度增加,羊肉的风味也会变得强烈。不同部位的羊肉因挥发性化合物的种类和含量不同而在风味上存在差异。羊肉的风味受到采食饲料类型的影响,高蛋白饲料、高能量饲料、风味植物、不饱和脂肪酸含量高的籽实及其他添加剂均在一定程度上影响羊肉的风味。饲养方式与疾病因素也会使羊肉风味发生变化。饲养密度、光照等环境因素对羊肉风味也有不同程度的影响。养羊生产中可以通过品种选择、营养调控及科学饲养管理等途径来改善羊肉气味和风味。     

反刍动物肌内脂肪及脂肪酸调控研究进展

脂肪作为食物中必不可少的养分,它不仅可以提供能量,还可以提供必需脂肪酸。脂肪的硬度、贮存稳定性受肌内脂肪及脂肪酸组成等影响,进而影响脂肪的营养价值、风味以及食用品质,而脂肪酸组成受动物种类、品种、性别和日粮等因素影响。反刍动物由于瘤胃氢化作用导致其脂肪酸饱和程度和异构程度高于单胃动物,从而使其肌内脂肪以及脂肪酸组成不同,导致其肉品质以及风味都不同。本文旨在综述反刍动物肌内脂肪及其脂肪酸构成调控的研究进展。     

日粮添加益生菌对干乳期奶牛生长性能、瘤胃发酵及氮平衡的影响

本研究旨在评估全混合日粮添加益生菌对干乳期奶牛生长性能、瘤胃发酵及氮平衡的影响.试验将体重为(440.92±3.33)kg、平均干乳期为42?d的60头荷斯坦奶牛随机分为2组,每组5个重复,每个重复6头.对照组饲喂玉米-豆粕型全混合日粮,处理组饲喂基础全混合日粮+200?mg/kg益生菌(枯草芽孢杆菌含量:1×106?...     

脂肪酸功能及其在养猪生产中应用的研究进展

脂肪酸是猪饲料中的一种重要营养成分,包括短链脂肪酸、中链脂肪酸和多不饱和脂肪酸等多种类型,它们除了提供能量外还对猪的肠道微生态、机体代谢、免疫机能、繁殖性能等具有调节作用。文章简述了不同饲料原料中脂肪酸的含量、脂肪酸的主要生物学功能及其在养猪生产中的应用效果,以期为养猪生产中合理应用油脂和脂肪酸提供依据。     

Research Progress on the Function of Fatty Acids and Application in Pig Production

Fatty acids are important compositions of nutrient,including short-chain fatty acids,medium-chain fatty acids and polyunsaturated fatty acids.They play a role in optimizing intestinal microflora,modulating nutrient metabolism,improving immunology and reproductive performance of pigs except for providing energy.This paper reviewed fatty acid profile of feed ingredients,basic biological functions of different variety of fatty acids and its application in swine industry to provide evidences for better using lipids and fatty acid in pig diet.     

The Influence of Tallow on Rumen Metabolism,Microbial Biomass Synthesis and Fatty Acid Composition of Bacteria and Protozoa

Abstract

Rumen metabolism, microbial biomass synthesis and microbial long chain fatty acid composition were studied in lactating cows fed at two levels of dry matter intake (L, 8.6 kg DM and H, 12.6 kg DM) with 0, 4 and 6% added tallow at the low feed level (L0, L4 and L6) and 0, 2, 4 and 6% at the high feed level (H0, H2, H4 and H6).

Fibre digestibility was not significantly affected by tallow addition. Increasing tallow level in the diet decreased the total VFA concentration, the ratio of acetic acid to propionic acid and the ammonia concentration in the rumen. Crude fat and fatty acid content in bacterial and protozoal dry matter increased with increased tallow level, especially due to an increase in fatty acids originating from the feeds. Microbial synthesis in the rumen and flow of amino acids to the duodenum was highest for medium fat intake at the high feed level.     

Effect of food deprivation on various parameters of rumen juice and blood of sheep]

In order to find out how short-time denutrition changes the concentration of some substances in the rumen fluid and the blood, tests with full-grown sheep were carried out. Fodder was withheld from sheep with inserted Jarrett fistulae for 48 hours after normal feeding. After 48 hours the animals were given concentrated fodder, after 52 hours exclusively hay. From the 72nd hour onwards the animals were provided with fodder as usual. Samples of the rumen fluid and blood samples were taken at the beginning of the test, after the last normal feeding and then in the 24th, 32nd, 48th, 52nd, 56th, 72nd and 96th hour. We could find out that, during the 48-hour denutrition, the pH-value of the rumen fluid turned alkaline and the concentrations of ammonia, volatile fatty acids and lactic acid decreased. The protein metabolism underwent a rapid change in the organism. The protein content of the blood plasma decreased, above all the albumin content, as well as the concentration of glycoproteins and volatile amino acids. Among the various amino acids, the concentration of glycine increased highly, that of alanine and valine just slightly. The concentration of most amino acids decreased or--of some of them remained the same. Among the paramters that are characteristic of lipid and carbohydrate metabolism, the total content of lipids and cholesterin decreased, and so did the concentration of blood sugar, lactic acid and pyruvic acid in the blood plasma. The results indicate that short-time denutrition has a considerable influence on the rumen fermentation and the intermediary metabolism of ruminants. The quickly arising lack of energy of ruminants slows down the protein synthesis and increases the glyconeogenesis from amino acids. The tissue is supplied with energy by the mobilisation of lipids.     

Effect of dietary energy supply and fat source on the fatty acid pattern of adipose and lean tissues and lipogenesis in the pig

Forty Large White barrows were used to determine whether the effects of dietary fat source (tallow or soy oil at 5% of the diet) on lipogenesis and fatty acid profile of porcine adipose and lean tissue were dependent on dietary digestible energy density (8.8 vs 14.0 MJ DE/kg). Barrows were allocated to one of four groups and offered a fixed amount of feed (170 g x BW0.569/d) from 27 to 105 kg BW. The fatty acid composition of the backfat layers (BF), omental fat (OF), and i.m. adipose tissue of longissimus muscle as well as the activity of lipogenic enzymes of the adipose tissues were determined. Growth performance and carcass characteristics were affected by the dietary energy level (P < 0.01) but not by fat source. In accordance with the lower carcass fat deposition, the activity of lipogenic enzymes were decreased in the low-energy groups (P < 0.01). Within dietary energy level, inclusion of soy oil resulted in increased proportion of PUFA that was compensated by decreased saturated (SFA) and monounsaturated fatty acid (MUFA) proportions (P < 0.01). The SFA changes accounted for 23 (BF) and 24% (OF) of the PUFA changes in the high-energy and 31 (BF) and 39% (OF) in the low-energy diets. The differences in the fatty acid proportions between the soy oil and tallow group were more pronounced in the low-energy groups (fat source x energy density interactions: P < 0.01). Pigs fed the soy oil, low-energy diet had decreased SFA (BF: 28%; OF: 30%) and MUFA (BF: 13%; OF: 19%) concentration, whereas PUFA concentration was increased (BF: 59%; OF: 88%) compared with pigs fed the soy oil, high-energy diet. However, in the tallow groups, pigs fed the low-energy diets had slightly decreased SFA (BF: 14%; OF: 12%) and relatively constant MUFA (BF: 3%; OF: 1%), whereas PUFA concentration increased (BF: 39%; OF: 62%) relative to pigs fed the tallow high-energy diet. Lipid content of the i.m. adipose tissue was decreased in the low-energy groups (P < 0.05). Contrary to what was observed in the adipose tissues, increased PUFA concentration in the neutral and polar lipid fractions of the longissimus muscle was predominantly compensated by reduced MUFA deposition. In the polar lipid fraction, the proportions of both SFA and MUFA were decreased by the low-energy diet. Thus, the extent to which tissue concentration of fatty acids are altered from dietary fats differing in the degree of unsaturation depends on the dietary energy level.     

脂肪酸合成酶基因的研究进展

在脂肪酸的合成过程中,脂肪酸合成酶(fatty acid synthase,FAS)是一种多功能的复合酶,是合成脂肪酸的关键酶,因此,动物体内脂肪酸合成酶蛋白的多寡、活性的高低对动物脂肪酸的合成及体脂的沉积具有重要的意义。近年来,国内外大量的研究报道了脂肪酸合成酶对脂肪合成、代谢的调控。作者将从脂肪酸合成酶基因结构特征,其与能量代谢及体脂沉积的关系,以及日粮养分与激素对脂肪酸合成酶基因的表达调控研究进行综述。