Amino acid nutrition in egg production industry

The egg production industry is facing various problems that need to be solved. For amino acid nutrition to achieve scientific and economical feeding of laying hens, it is necessary to elucidate the content, digestibility, or availability of nutrients of feedstuffs and feeds and the requirement of amino acids for laying hens. In addition, improvement to quality of eggs and meat of spent hens, methods of management and development of new feedstuffs are essential. For sustainable animal production, decrease in excreta and animal welfare should be studied. The real‐time determination of content and digestibility of amino acids in feedstuffs are essential for formation of feeds. Recent advances in the near infrared reflectance analysis will be able to determine the content, digestibility and availability of nutrients in feedstuffs and feeds, if we have a supplemental amount of conventional analysis to define the calibration population. The amino acid requirements are affected by various factors. Therefore the method to quickly and exactly determine amino acid requirements in response to various factors is necessary. By using plasma free amino acid concentration as a criterion, it is possible to determine amino acid requirements in various conditions of laying hens within a short experimental period, repeatedly using the same animals. Because the amino acid requirements differ among individual animals, it should be expressed as grams per hen per day. Practically, it is impossible to formulate various feeds for individual hens. The various expressions have been developed and these expressions have advantages and disadvantages. The nitrogen excretion of laying hens is easily reduced by reducing dietary nitrogen levels and restricting the feed intake. The availability of amino acid may be improved by feeding management, and supplementing enzyme, but the quality of eggs and meat of spent hens and welfare of laying hens are not affected by amino acid nutrition.     

Alternative prediction methods of protein and energy evaluation of pig feeds

Precise knowledge of the actual nutritional value of individual feedstuffs and complete diets for pigs is important for efficient livestock production. Methods of assessment of protein and energy values in pig feeds have been briefly described. In vivo determination of protein and energy values of feeds in pigs are time-consuming,expensive and very often require the use of surgically-modified animals. There is a need for more simple, rapid,inexpensive and reproducible methods for routine feed evaluation. Protein and energy values of pig feeds can be estimated using the following alternative methods: 1) prediction equations based on chemical composition; 2)animal models as rats, cockerels and growing pigs for adult animals; 3) rapid methods, such as the mobile nylon bag technique and in vitro methods. Alternative methods developed for predicting the total tract and ileal digestibility of nutrients including amino acids in feedstuffs and diets for pigs have been reviewed. This article focuses on two in vitro methods that can be used for the routine evaluation of amino acid ileal digestibility and energy value of pig feeds and on factors affecting digestibility determined in vivo in pigs and by alternative methods. Validation of alternative methods has been carried out by comparing the results obtained using these methods with those acquired in vivo in pigs. In conclusion, energy and protein values of pig feeds may be estimated with satisfactory precision in rats and by the two-or three-step in vitro methods providing equations for the calculation of standardized ileal digestibility of amino acids and metabolizable energy content. The use of alternative methods of feed evaluation is an important way for reduction of stressful animal experiments.     

Fine particles and dust in animal feeds--quantitative and qualitative (fungi, bacteria and LPS) aspects

Unground feedstuffs like cereals and roughage which are conspicuous by high proportions of finer particles and dust have to be estimated as risky environmental factors due to the accumulation of microorganisms (moulds, bacteria and lipopolysaccharides) and mites in the fines frequently. The dusty fraction in feed samples should be separated by sensorial inspection of feedstuffs (for example by sieves) and has to be looked at (using pocket lens) critically to find out lacks in the hygienic quality of feedstuffs. Dusty qualities of roughage contain high counts of moulds frequently, therefore a mycological investigation is to be recommended for these samples. The feedstuffs may influence the quantity and quality of air dust within the stable as the starch content (similar to the fed diet) indicates. Likewise corresponding LPS contents were measured in feeds and airborne dust of pig stables. Due to the high counts of microorganisms in the dusty fraction of cereals an intensive cleaning procedure for cereals has to be recommended for minimizing the load of germs; a reduced risk for deterioration can be expected. The residues of cleaning processes (combined mechanic/pneumatic procedures) of cereals should not be reutilized in the production of compound feeds by feed manufacturers, the nutritive value is relatively low anyway due to the high ash- and fiber-contents. Potential risks of dusty feedstuffs to animals' health and the influences of mites, moulds and lipopolysaccharides on the development of gastrointestinal and respiratoric disturbances are discussed. Experimental investigations are needed to elucidate the role of inhaled dust--and its content of lipopolysaccharides especially--in the development of respiratory diseases in veterinary medicine.     

杜马斯燃烧法与凯氏法测定饲料含氮量的比较研究

以20种常见的饲料原料和2种化学标准物为试验材料,分别采用凯氏法和杜马斯燃烧法测定各饲料样本中的含氮量,并将其中11种样本分别送往3个实验室进行凯氏法和杜马斯燃烧法的测定,分析误差来源,以确立一种快速无污染的饲料含氮量测定方法.结果表明,两种测定方法呈显著线性相关（r=0.999 8,P＜0.001）,而且大部分蛋白质饲料和能量饲料的含氮量测定值间没有差异（P＞0.05）,变异系数（CV）＜5%,但在测定羊草、小麦秸、玉米秸、稻草时,两种方法的测定值间存在显著差异（P＜0.05,CV＜5%）.在3个不同的实验室使用凯氏法测定时,7种样本间存在显著差异（P＜0.05）,其中2种样本的CV大于5%;而使用燃烧法时,只有2种样本存在显著差异（P＜0.05）,并且所有样本的实验室间CV均小于5%.11种饲料样本在3个不同实验室间测定值的平均CV值表现为燃烧法明显小于（P＜0.01）凯氏法.杜马斯燃烧法可以作为测定动物饲料和饲粮含氮量的常规方法.     

抽样调查北京地区猪场饲料及饲料原料赭曲霉毒素A污染状况

本研究旨在采用免疫亲和柱高效液相色谱法测定北京地区猪场饲料及饲料原料中赭曲霉毒素A(OTA)的含量,以了解北京地区饲料中OTA污染情况。试验抽样采集北京市昌平区、大兴区、延庆区、平谷区、顺义区5个区县15个猪场131份饲料样[玉米14份、豆粕11份、麸皮13份、干酒糟及其可溶物(DDGS)17份、猪全价配合饲料76份]进行OTA含量的测定。结果表明:玉米、豆粕、麸皮和DDGS中OTA的检出率分别为92.86%、63.64%、76.92%和100.00%,平均含量分别为22.12、10.81、7.78和22.46μg/kg,仅发现玉米中OTA含量超标,超标率为7.14%。乳猪料、仔猪料、中猪料、大猪料、怀孕母猪料和哺乳母猪料中OTA的检出率分别为100.00%、85.70%、85.70%、94.44%、90.00%和100.00%,平均含量分别为4.39、15.74、11.66、13.07、47.75和15.40μg/kg,仅发现怀孕母猪料中OTA含量超标,超标率为20.00%,其他配合饲料中OTA含量均较低。综上所述,不同饲料或饲料原料中OTA含量存在差异,本调研结果发现玉米和怀孕母猪料中OTA含量部分超标,其他猪全价配合饲料及饲料原料中OTA含量均未超标。     

微波炉测定三叶草含水量的研究

用微波炉加热法快速测定三叶草含水量。结果表明:微波炉法较烘箱法测定值精确度高、准确性好;在测定高水分(67%～80%)红三叶时,采用5min法好,而在测定低水分(44%～66%)红三叶时,采用4min法好;红三叶的取样大小分别为10g、15g、20g、25g,其间差异不显著;白三叶水分测定用微波炉4min法好,取样大小以15g、20g较好。     

雨淋及干燥方式对紫花苜蓿干草品质的影响

在紫花苜蓿(Medicago sativa L.)收获调制期间,极易遭遇雨淋,雨淋及干燥方式对紫花苜蓿干草品质的影响较大。本研究以未雨淋和雨淋紫花苜蓿为对象,分别对其进行烘干、晒干和阴干处理,并分析紫花苜蓿干草的营养品质。结果表明:雨淋后紫花苜蓿的中性洗涤纤维含量显著升高,水溶性碳水化合物含量显著降低,相对饲用价值降低;雨淋对紫花苜蓿干草粗蛋白、木质素和酸性洗涤纤维含量没有显著影响。经烘干和晒干处理的紫花苜蓿干草粗蛋白、水溶性碳水化合物含量及相对饲用价值显著高于阴干处理,酸性洗涤纤维含量则是烘干和晒干处理显著低于阴干处理;干燥方式对紫花苜蓿干草中性洗涤纤维和木质素含量没有显著影响。雨淋和干燥方式的交互作用显著影响了紫花苜蓿干草的营养成分和相对饲用价值,未雨淋×烘干处理下的粗蛋白、水溶性碳水化合物含量及相对饲用价值最高,中性和酸性洗涤纤维及木质素含量最低。总之,未雨淋紫花苜蓿的品质和相对饲用价值高于雨淋后的紫花苜蓿。干燥方式以烘干最能保存紫花苜蓿的品质,其次是晒干,效果最差的干燥方式为阴干。遭受雨淋后,采用烘干和晒干的方式能较好的保存紫花苜蓿干草营养成分。     

Determination of feeding value based on simple food characteristics. 1. Determination of the digestibility of green foods and their preservation products]

Regression techniques may be used to establish close relations between the crude fibre content and digestibility data of organic materials (total digestibility). It was shown from regression equations calculated for a number of feedingstuffs that the total digestibility of a feedstuff may be calculated, with a sufficient degree of accuracy, from the crude fibre content of the material. The range of variations from most of the digestibility data obtained for various feedstuffs, was clearly below the limit given (2.5%). When regression equations are used the variation limits should always be indicated for which they had been established. Differences within the different groups of feedstuffs are so small that in many instances, the same equation may generally be used for feedstuffs of the same group. Similarly, equations for calculating digestibility values may be derived on the basis of the lignin content of a material, although the range of variations will, in this case, be wider when compared with the crude fibre content. The reason for this must be seen in the greater uncertainty of the lignin method. Analogous regression equations may be found for the different conserving products of green feeds, in which certain alterations have to be made corresponding to the different methods of conserving used. On the one hand, these are accounted for by changes in the crude fibre content brought about by biochemical reactions during the conserving process on the other hand a special influence of conserving form can be observed. The content of digestible crude protein in green feeds can be established, with a high degree of accuracy, from the crude protein content of the material. The content of digestible organic matter can be calculated from the digestibility of organic matter and from the ash content of the material. The content of digestible organic matter is, in turn, closely related to the content of energetic feed units in a particular material.     

Salmonella investigation in an Ontario feed mill.

The frequency of Salmonella contamination of feedstuffs and finished broiler chicken feeds at an Ontario feed mill were investigated over a four-month period. Samples of feed ingredients and finished pelleted feeds were collected at various points during manufacture and cultured in trypticase soy broth prior to selective enrichment for isolation of Salmonella. Salmonella contamination was found in 4.3% of 93 finished pelleted broiler feeds examined. The contamination appeared to result primarily from the incorporation of contaminated animal protein ingredients into the feed. Meatmeal and the broiler, premix, which contained meatmeal as a filler, were most frequently contaminated followed by feather meal. Pelleting failed to eliminate the Salmonellae from the feeds. The methods used failed to detect Salmonella in the environment of the feed mill or its delivery trucks. Recommendations for control are made.     

Comparison of calculated and experimentally determined SID of CP and AA in complex diets differing in AA contents for grower finisher pigs

In practice, the content of standardized ileal digestible AA in complex feeds for pigs is calculated on the basis of tabulated values for individual feedstuffs. It comes into question, however, whether this truly reflects an accurate content based upon the estimate made for the individual feedstuffs. The objective of this study was to compare standardized ileal digestibility (SID) of crude protein (CP) and selected AA in complex feeds for grower and finisher pigs either calculated or experimentally determined. Six diets with increasing AA levels were prepared for grower (BW from 30 to 70 kg) and finisher (BW from 70 to 120 kg) feed. Crystalline L‐lys, DL‐met and L‐thr were added to both diets, L‐trp and L‐val only to the grower feed. SID of both CP and AA was calculated from feed tables and experimentally determined in six adult minipigs (MINILEWE) with ileorectal anastomosis. With increasing AA levels, experimentally determined SID of supplemented AA increased (p < 0.05), but SID of CP (p ≥ 0.05) was not affected. In both grower and finisher feed, calculated and experimentally determined SID of CP, Met, Cys, Trp, Ile and Tyr differed by more than 2% units, but those of Lys and His only in the finisher feed. Yet this effect was not directly consistent. The margin of error following estimation of SID of AA via tabulated values for individual feedstuffs, however, seems to be acceptable for practical use.     

晾晒方式对构树失水速率及饲用价值的影响

构树(Broussonetia papyrifera)是桑科木本植物,因其蛋白质含量较高而被西南地区广泛用于饲料加工业。以构树不同晾晒方式进行干草调制研究,探讨其失水速率及饲用价值变化,以优化构树干草调制方法,保存青饲料的营养成份,替代青饲料或精饲料。采用聚类分析将23种干燥方法分为快速干燥、中速干燥和慢速干燥3类,从平均水分散失量中发现堆小垛后晾晒能提高水分散失速率,干燥最快的方法是压扁+10cm切短。基于因子分析的饲用价值计算发现,最适的构树干草调制方式是6cm切短+2%K2CO3,其饲用价值得分可达0.514。若采用破坏茎干结构与喷洒K2CO3组合方式,应选择切短方式减小维管束出露面积,以提升饲用价值。     

Effect of feeding sheep on naturally spoiled rice straw, clover hay and concentrate feed mixtures

The effects of feeding naturally contaminated feedstuffs to sheep were investigated through feeding of contaminated and uncontaminated clover hay, rice straw, and concentrate feed mixture were compared. The highest level of contamination with fungi was observed in the concentrate feed mixture followed by clover hay and rice straw. The most dominant mycotoxin in the contaminated feedstuffs was zearalenone. Contamination resulted in increases of crude protein, ash and silica in feedstuffs while both ether extract and crude fibre decreased. In vivo digestibility of different diet constituents in both contaminated and uncontaminated feedstuffs were determined using four mature Rahmani rams. Contamination resulted in significant increase in the digestibility of dry matter, crude fibre and energy. Contamination affected feed intake of the different feedstuffs particularly the concentrate feed mixture. A metabolism trial was also conducted to study the nitrogen and mineral balance. Retention of nitrogen and calcium was reduced when mouldy feeds were given. On the other hand, magnesium was relatively increased. Blood analysis for sheep at the end of the trials resulted in elevated values of inorganic phosphorus and phospholipid phosphorus and declined total nitrogen, calcium, cholesterol, calcium/phosphorus ratio and cholesterol/calcium ratio due to feeding on mouldy ration. Results of the urine analysis during the metabolism trials proved that mouldy ration increased the estimated values of the concentration of calcium, magnesium and vitamin C; whereas pH values, total nitrogen, ammonia nitrogen and inorganic phosphorus were declined during the feeding on the mouldy ration. Mouldy feeds tested, seemed to have toxic, nephritic and hepatic effect.     

Effects of oils on feed mildew and quality

This study was performed to determine the effects of oils on feed mildew and feed quality. Under different moisture content conditions (10%, 13% and 16%), the basal feeds were supplemented with 4%, 6%, 8%, 10% and 12% soybean oil. In addition, at different moisture content levels (10%, 13% and 16%), the basal feed was supplemented with 12% of various types of oil (soybean, peanut, corn and fish). Subsequently, a mixed mold spore suspension was added. The feed samples were incubated at 28°C, and the total mold, water activity (Aw), moisture, acid value, crude protein (CP), crude lipid (CL), crude ash (CA) and nitrogen‐free extract (NFE) levels were determined at 15, 30, 45 and 60 days. The results showed no significant variations in the feed moisture, CP, CL, CA and NEF contents. However, the acid value gradually increased in the feed samples with an extended incubation time and increasing initial moisture. The feed moisture content was a critical factor controlling feed mildew, and high levels of oil supplementation caused an elevated Aw. Additionally, peanut oil promoted mold growth in feed. These results provide a reference for the production and scientific management of formulated feed.     

Feeding and performance of pigs in smallholder production systems in Northern Lao PDR

A survey was carried out in the North of Lao PDR to study feeding systems and the performance of pigs in smallholder systems. A total of 341 farmers from five provinces were interviewed. To feed their pigs, farmers mainly rely on feedstuffs produced on the farm and collected from areas near the village. The feedstuffs used included by-products such as rice bran and distiller’s waste, planted feeds, mainly maize and cassava, and various green plant materials. The feedstuffs used are usually high in energy and low in protein content, and the only readily available protein source is green plant material. This results in nutritionally imbalanced diets and as a result poor pig performance. The average growth rate of pigs in these systems was found to be only approximately 100 g/day. The reproductive performance of sows was found to be relatively low, as is the case of local breeds in the region, with an average litter size at birth of 6.8 piglets. The mortality of piglets was as high as 50% and was a main concern of farmers. In order to improve the productivity of pigs in smallholder systems, there is a need to find alternative feed resources to improve the nutritional feed quality, and to develop management systems which are suited to the needs and practices of smallholders.     

Reducing the proportion of animal protein in feed for rainbow trout (Salmo gairdneri). 2. Supplementation of methionine and lysine

Continuing previous investigations, two test feedstuffs whose fishmeal content had been reduced to 5% and which were supplemented with 4.5 g methionine and 5.0 g lysine per kg resp. 6 g methionine and 6 g lysine per kg were proofed in comparison with a fattening feed for trout as customary in trade and with a fish meal content of 35%. The content of animal protein in the control feed was at least 75% (crude protein content 41%), in test feed I at most 35% (crude protein content 35.4%), in test feed II at most 17% (crude protein content 33.9%). All feedstuffs had the same energy content. The tests were made with rainbow trout (Salmo gairdneri) of 80...100 g at the beginning and at water temperatures of 11...12 degrees C. They were conducted over a period of 112 days. After giving the same amount of feed, growth of and feed expenditure for the fish feed with the test feedstuffs were less suitable than of those fish which had received the control feed. Concerning the protein efficiency ratio, the productive protein value and the energetic expenditure too, the best results were achieved with the control feed.     

辽宁绒山羊常用饲料营养价值评定

采集辽宁绒山羊常用饲料17种23个样品,应用康奈尔净碳水化合物-蛋白体系(CNCPS)提出的原理和方法对饲料营养价值进行评价。测定饲料原料常规营养成分以及非蛋白氮(NPN)、可溶性蛋白(SCP)、酸性洗涤不溶蛋白(ADFIP)、中性洗涤不溶蛋白(NDFIP)及酸性洗涤纤维(ADF)、中性洗涤纤维(NDF)、木质素(LIGNIN)和淀粉,并对饲料原料的蛋白质和碳水化合物进行分类分析。结果表明:粗饲料可溶性蛋白质主要是NPN,真蛋白含量少,3种蛋白质饲料可溶蛋白主要是真蛋白,NPN含量少;所采集灌木类饲料纤维含量尤其是慢速降解细胞壁成分含量低,可快速降解糖类和可利用蛋白质含量高,质量优于秸秆和干草等其他粗饲料;棉粕的不可消化纤维和不可消化蛋白质含量高,可消化利用性较差。豆皮的蛋白质含量较低,主要是慢速降解纤维成分占绝大多数。     

稻草微生物饲料干物质消失率的研究

试验对不同水分添加量、不同发酵时间的稻草微生物饲料干物质在山羊瘤胃内的消失率进行系统研究,旨在为评定稻草微生物饲料的营养价值提供基础数据.试验选择3只安装永久性瘤胃瘘管贵州黑山羊,采用尼龙袋法,以不加水不发酵为对照组,分别测定了水分添加量为40％、50％、60％和70％的稻草微生物饲料,经10、20、32 d发酵后干物质在山羊瘤胃内的消失率.结果显示：发酵时间和水分添加量对稻草微生物饲料中干物质消失率均具有显著影响.从发酵时间看,发酵32 d的饲料在山羊瘤胃内各时间点的干物质消失率均高于对照组（P＜0.01）和其他试验组（P＜0.05）;从饲料水分添加量看,96 h的干物质消失率均以水分添加量60％组最高.发酵10 d水分添加量60％组为36.52％,比对照组高10.94％（P＜0.05）,比40％组高0.74％ （P ＞0.05）,比50％组高0.41％ （P ＞0.05）,比70％组高0.19％ （P＞0.05）;发酵20 d水分添加量60％组为44.32％,比对照组高34.63％ （P ＜0.01）,比40％组高7.16％ （P ＜0.05）,比50％组高6.00％ （P ＜0.05）,比70％组高3.65％（P＞0.05）;发酵32 d水分添加量60％组为,比对照组高42.68％ （P ＜0.01）,比40％组高7.36％（P＜0.05）,比50％组高6.94％ （P ＜0.05）,比70％组高6.27％ （P ＜0.05）.结果表明：以水分添加量为60％,发酵32 d制成的稻草微生物饲料干物质消失率效果最好.     

抽样调查北京地区猪场饲料及饲料原料玉米赤霉烯酮污染状况

本研究采用免疫亲和柱高效液相色谱法测定了北京地区猪场饲料原料及全价饲料中玉米赤霉烯酮（ＺＥＮ）的含量,以了解北京地区饲料中 ＺＥＮ的污染情况。试验抽样采集北京市昌平区、大兴区、延庆区、平谷区、顺义区 ５个区县 １５个猪场 １３１份饲料样［５５份玉米、豆粕、麸皮、干酒糟及其可溶物（ＤＤＧＳ）原料,７６份猪全价饲料］进行 ＺＥＮ含量的测定。结果表明：玉米、豆粕、麸皮、ＤＤＧＳ和全价饲料中 ＺＥＮ的检出率分别为 １００．００％、５４．４５％、１００．００％、１００．００％和 ５８．８８％,超标率分别为 ０．００％、０．００％、０．００％、４１．１８％和 ０．００％,平均含量分别为 １０９．０８、９．１９、１４．９２、８８２．６８和 ５８．８８μｇ／ｋｇ。结果提示,不同饲料原料中 ＺＥＮ含量存在差异,ＤＤＧＳ中 ＺＥＮ平均含量超标,猪全价饲料及玉米、豆粕等饲料原料中 ＺＥＮ平均含量均未超标。     

泰拉霉素国家对照品的标定研究

为了有效控制泰拉霉素原料及注射液的产品质量,研制了泰拉霉素国家对照品。采用精制后的泰拉霉素为原料进行本批对照品的研制,原料分装后进行质量检测及均匀性评价,并标定含量。采用红外分光光度法、费休氏水分测定法等对其进行理化分析,利用高效液相色谱法进行有关物质测定及均匀性检验,采用质量平衡法进行标准物质含量计算,并通过差示扫描量热法对质量平衡法的准确性进行验证。研制的泰拉霉素国家对照品的含量为98.3%,采用多种不同方法对本品进行定性与定量研究,确保了国家标准物质标定结果的准确性。本对照品可用于泰拉霉素原料及注射液的鉴别与含量测定,对于提高和保证兽药产品质量具有重要意义。     

Iodine deficiency in ruminants. 1. The iodine content of feed, plants and drinking water

Dependent on the species, feedstuffs and plants differ considerably in their iodine content. Among the I-poorest feedstuffs there are grain concentrates, extracted soybean and rapeseed oil meals, mixed feed (without I-containing mineral mixture) and grasses. The I content of the plants decreases with proceeding growth. The I intake of ruminants via vegetable feed and drinking water is affected by the distance of the site from the seaside and the geological origin of the soil material. Ruminants get considerably less iodine via feedstuffs and water in the southern territory of the GDR than in the central and northern areas. Therefore, mineral mixtures for cattle and sheep are supplemented with 18 mg KIO3 per kg mixture in the southern districts. The I analysis of 205 charges of mineral mixtures revealed only a mean I content of 7 (3.8-11.3) mg per kg mixture.