Partitioning nitrogen and amino acids for pregnancy and lactation in swine: a review

Nitrogen and amino acid requirements for maintenance, maternal growth, mammary growth and products of conception were partitioned on the basis of data from numerous sources. These data were compared with N retention values obtained from balance trials conducted during pregnancy. Carefully conducted N balance trials will yield N retention data that are reasonably comparable with N deposition data determined from tissue analyses. Based on indispensable amino acid (IAA) requirements for maintenance and pregnancy, the IAA were partitioned among maintenance, maternal growth, and products of conception including mammary growth. The nonspecific N requirement also was estimated in these calculations. Results indicate that the pregnancy requirements for total N and nonspecific N could be reduced considerably from present recommendations (NRC, 1988). Nitrogen and IAA requirements for lactation were partitioned between maintenance and milk production. Estimates of total N and nonspecific N that were derived factorially also were substantially less than present recommendations (NRC, 1988).     

Digestibility of nitrogen and amino acids in soybean meal with added soyhulls

This study was designed to quantify the effect of soyhulls on N and AA digestibilities of soybean meal for growing pigs. Soyhulls were incorporated into 17% CP diets containing 33.25% soybean meal (SBM) at 0, 3, 6, or 9% (as-fed basis) and fed to 35-kg barrows to determine their effect on apparent and true digestibility of DM, GE, N, and AA measured at the terminal ileum. Positive and negative control diets containing 1.05% lysine were formulated with 35% SBM and 27% soy protein concentrate (SPC), respectively. A low-protein, casein-based diet was used to estimate endogenous AA losses. Soyhulls were incorporated into experimental diets at the expense of cornstarch, and SBM levels were adjusted to accommodate the contribution of CP from soyhulls. Fourteen pigs were surgically fitted with simple T-cannula at the distal ileum and fed the seven semipurified cornstarch diets based on a replicated 7 x 7 Latin square design. Each period lasted 7 d, with diet acclimation from d 1 to 5 and ileal sample collection for 12 h on d 6 and 7. Feed was offered at a level of 90 g/kg BW(0.75) in two equal portions at 0800 and 2000. Apparent ileal digestibilities of DM and GE decreased approximately six percentage units with the addition of soyhulls (linear, P < 0.05), whereas N was not affected. Both apparent and true ileal digestibilities of arginine, histidine, lysine, phenylalanine, aspartic acid, serine, and tyrosine also exhibited a decrease (linear, P < 0.05) of up to five percentage units with the addition of soyhulls. True ileal lysine digestibility of SBM decreased from 90.3 to 87.7% with the addition of 9% soyhulls. The endogenous nutrient fraction measured at the distal ileum was rich in proline, glutamic acid, and glycine, with losses greater than 1,000 mg/kg of DMI for each AA, and contained minimal amounts of tryptophan, methionine, and cystine. The current data suggest that a 0.2% decrease in some true ileal indispensable AA digestibilities may result with each 1% increase in soyhull inclusion in semipurified diets containing SBM as the sole source of AA as fed to growing pigs.     

Endogenous nitrogen metabolism processes in 15N-labeled swine. 2. Fecal excretion of amino acids and 15N-labeled amino acids with diets differing in crude fiber content

Four pigs were labelled with 15N-ammonium salt over a period of 10 days in the feeding of a fishmeal diet, a fishmeal diet + partly hydrolysed straw meal, a field bean diet and a field bean diet + partly hydrolysed straw meal. The 14N-amino acids and the 15N-amino acids excreted in faeces showed highly significant correlation coefficients with the increasing content of crude fibre in the diets, which amounted to 3.0, 5.3, 10.0 and 12.1% in the DM. The following sequence was established for the growth angle (tan alpha) of the essential 14N-amino acids: Leu, Lys, Arg, Thr, Phe, Ile, Val, His and of the 15N-amino acids: Lys, Arg, Val, Leu, Ile, Thr, Phe and His. As Lys, His and Thr cannot incorporate 15N in transamination reactions in the intermediate metabolism, their level of labelling was considerable in case of diet 4. Nevertheless, tan alpha is highest for 15N-Lys and lowest for 15N-His. This means that His in contrast to Lys, parallel to increased synthesis, is also increasingly decomposed in the large intestine. In contrast to this, proline was not labelled with 15N even with the highest content of crude fibre in the diet. Despite this, 14N-proline excretion, next to glutamic acid, increased most with the growing content of crude fibre in the diet. Due to the hydrophilic character of glutamic acid and the increased water influx in the large intestine and the increased content of crude fibre in the diet, a growing proline transport parallel to the increased influx of crude fibre and water must be assumed. If the growth angle tan alpha for the excretion of 14N-amino acids is ascertained regressively for a crude fibre content of diet of 10%, one can prove from the proportion of the amino acids and a comparison from literature for faecal bacteria and ileum digesta that the amino acid composition for this measuring point largely corresponds to that of bacteria protein.     

A review of the effects of dietary organic acids fed to swine

Animal production depends on nutrient utilization and if done there is an accelerated momentum towards growth with a low cost to feed ratio Public concern over the consumption of pork with antibiotic residues of the animals fed with antibiotic growth promoters(AGP) has paved the way to use other additives like herbs and their products,probiotics,prebiotics etc.Numerous feed additives are in vogue for achieving this target and one such classical example is the usage of organic acids and their salts.Usage of organic acids was in progress for over four decades.Early weaned piglets are(3-4 weeks age) exposed to stress with a reduced feed intake,little or no weight gain.This post weaning lag period is due to a limited digestive and absorptive capacity due to insufficient production of hydrochloric acid,pancreatic enzymes and sudden changes in feed consistency and intake.Lowering dietary pH by weak organic acids was found to overcome these problems.The main activity of organic acids is associated with a reduction in gastric pH converting the inactive pepsinogen to active pepsin for effective protein hydrolysis.Organic acids are both bacteriostatic and bactericidal.Lactic acid has been reported to reduce gastric pH and delay the multiplication of an enterotoxigenic E.coli.These acids are the intermediary products in Kreb's cycle and thus act as an energy source preventing the tissue breakdown resulting from gluconeogenesis and lipolysis.Excretion of supplemental minerals and nitrogen are minimized with organic acids as these form complexes with minerals and aids for their bio-availability.Short chain fatty cids like acetic,propionic and n-butyric acid produced by microbial fermentation of dietary fibre in the large intestines may increase the proliferation of epithelial cells and have stimulatory effects on both endocrine and exocrine pancreatic secretions in pigs.Organic acids also enhances apparent total tract digestibility and improves growth performance.It is concluded that organic acids and their salts increase the protein utilization especially in weaner pigs and improves production indices.     

日粮中添加有机酸对猪消化道的影响(综述)(续2)

本文是《日粮中添加有机酸对猪消化道的影响(综述)》的第三部分,主要介绍有机酸的使用方法和单体有机酸在动物营养中的应用。     

日粮中添加有机酸对猪消化道的影响(综述)(续1)

本文是《日粮添加有机酸对猪的影响(综述)》的第二部分,主要介绍有机酸的使用方法。     

Biotin in swine production: A review

Biotin, an essential water-soluble vitamin, is a cofactor of a number of enzyme systems responsible for carboxylation and transcarboxylation reactions. These reactions play a major role in the metabolism of carbohydrates and nucleic acids, in the synthesis of fatty acids, proteins and purines, and in the deamination of amino acids. In the past, it was believed that supplemental biotin was not required in swine diets because of its wide distribution in feedstuffs generally used in the formulation of swine diets, and its known synthesis by the pig's intestinal microflora. Interest in biotin nutrition for swine, however, was rekindled when several field reports in the mid-1970s described disease conditions similar to those reported for experimentally induced biotin deficiencies (poor growth in young pigs, low plasma biotin levels, alopecia and pustule formation in the skin and lesions of the hoof and sole of the toes). These conditions were reported to be responsive to biotin supplementation in many cases, but control treatments were usually not included so that definitive conclusions could not be made. Results from properly controlled research are now available, especially from long-term sow studies (three to four parities), which suggest that supplemental biotin may improve one or more of the following: poor litter size, conception rate or weaning to estrus interval, toe lesions and poor haircoat condition. Milk biotin concentration and plasma biotin concentration of sows and piglets were reported to be elevated when supplemental biotin was fed. The amount of biotin in feedstuffs varies from 20 to 2600 parts per billion (p.p.b.), but availability values have not been determined for pigs, although chick bioavailability values suggest that biotin in commonly used grain and protein sources is poorly available. Numerous environmental and nutritional factors may influence the occurrence of a biotin deficiency in swine or alter the level of biotin required in the diet to meet the animal's needs. Using presently available feedstuffs and under modern swine production conditions, a marginal biotin deficiency is possible. There are, however, many unanswered questions and a need for more research to better understand the role of biotin in swine nutrition. Swine producers experiencing poor reproductive performance in their sow herds, associated with excessive loss of hair and severe foot lesions, should evaluate the biotin content of their sow diet and consider supplemental biotin.     

The control of adenohypophysial hormone secretion by amino acids and peptides in swine

Several different amino acids and peptides control secretion of adenohypophysial hormones and this control may be indirect, via the modulation of hypothalamic hormone secretion. Indeed, classical hypothalamic hormones (e.g., gonadotropin-releasing hormone [GnRH], growth hormone-releasing hormone [GHRH], somatostatin, etc.) may be released into the hypothalamo-hypophysial portal vasculature, travel to the adenohypophysis and there stimulate or inhibit secretion of hormones. Alternatively, some amino acids and peptides exert direct stimulatory or inhibitory effects on the adenohypophysis, thereby impacting hormone secretion. In swine, the most extensively studied modulators of adenohypophysial hormone secretion are the excitatory amino acids (ExAA), namely glutamate and aspartate, and the endogenous opioid peptides (EOP). In general, excitatory amino acids stimulate release of luteinizing hormone (LH), follicle-stimulating hormone (FSH), growth hormone (GH), and prolactin (PRL). Secretion of adenohypophysial hormones induced by ExAA is primarily, but perhaps not exclusively, a consequence of action at the central nervous system. By acting primarily at the level of the central nervous system, EOP inhibit LH secretion, stimulate GH release and depending on the animal model studied, exert either stimulatory or inhibitory influences on PRL secretion. However, the EOP also inhibited LH release by direct action on the adenohypophysis. More recently, peptides such as neuropeptide-Y (NPY), orexin-B, ghrelin, galanin, and substance P have been evaluated for possible roles in controlling adenohypophysial hormone secretion in swine. For example, NPY, orexin-B, and ghrelin increased basal GH secretion and modulated the GH response to GHRH, at least in part, by direct action on the adenohypophysis. Secretion of LH was stimulated by orexin-B, galanin, and substance P from porcine pituitary cells in vitro. Because the ExAA and various peptides modulate secretion of adenohypophysial hormones, these compounds may play an important role in regulating swine growth and reproduction.     

日粮中添加有机酸对猪消化道的影响(综述)

动物的生产力取决于它们对养分的利用情况,如果一切顺利,动物就会加速增长,成本饲料比降低。公众担心食用饲喂抗生素生长促进剂的猪会生产出带有抗生素残留的肉,这为使用其他饲料添加剂如中草药及其制品、益生菌和益生元等铺平了道路。有许多饲料添加剂为实现这一目标而大量流行,其中一个经典的案例是有机酸以及有机酸盐的使用。有机酸的使用已经持续了四十多年。早期断奶仔猪(3～4周龄)面临着采食量减少的应激,甚至导致体重几乎无增加。仔猪在断奶后出现的这种生长停滞是由于其消化和吸收能力有限所致,也是盐酸和胰腺酶分泌不足以及日粮一致性和采食量的突然变化带来的结果。研究表明利用弱有机酸来降低日粮pH可以克服这些问题。有机酸的主要活性与降低胃内容物pH有关,其可将胃蛋白酶原转变为具有活性的蛋白酶,以进行有效的蛋白质水解。有机酸既能抑菌又能杀菌。据报道,乳酸可以降低胃内容物的pH,并延缓产肠毒素性大肠杆菌的增殖。这些酸性物质是克雷伯氏菌循环的中间产物,它们作为消化道上皮细胞的能量来源,可以防止糖异生和脂解作用引起的组织降解。有机酸可尽量减少添加的矿物质和氮的排泄量,这是因为有机酸会与矿物质形成复合物,提高它们的生物利用率。大肠中的日粮纤维经微生物发酵会生成乙酸、丙酸和正丁酸等短链脂肪酸,它们能够促进消化道上皮细胞的增殖,且对猪胰腺的内分泌和外分泌产生刺激作用。有机酸还可以提高猪的表观总消化道消化率,并改善动物的生长性能。综上,有机酸及有机酸盐可以提高猪尤其是断奶仔猪的蛋白质利用率,同时提高生产指标。     

Prececal crude protein digestibility and absorption of amino acids from lupines in swine

The apparent precaecal (pc) digestibility of crude protein (CP) and the apparent pc absorption of the key amino acids (AA) lysine, methionine, cystine, isoleucine, threonine and tryptophan from two yellow sweet lupine (L. luteus) varieties (Bornova, Borluta) and one narrow-leafed sweet lupine (L. angustifolius) were determined with ileorectostomized pigs. When the influence of the basal diet (barley or protein free rations) was checked with regard to absorption there were significant differences in a few cases only. In comparison to soybean meal (SBM) the methionine of the lupines was significantly worse, the cystine significantly better absorbed. The CP and the other key AA of the lupines showed approximately the same or even slightly higher pc absorption than those of SBM. With the example of the pc-absorbable AA amounts it was shown that sweet lupines with an approximately equally high CP content as in SBM cannot completely substitute the latter even after lysine and methionine supplementation because the absorbable tryptophan is by far insufficient, and isoleucine and threonine make up only 75% in comparison to SBM. On the basis of the content of pc-digestible CP and pc-absorbable AA it becomes possible to substitute high-grade imported protein concentrates according to their ability of AA supply in the feeding of pigs completely or partly by home-made protein feeds.     

The activity of and requirements for selected amino acids in growing female swine. 2. Methionine and cystine

The methionine/cystine efficiency of ten protein sources including that of different charges of the same protein source was ascertained in N balance experiments with a total of 60 female pigs in the live weight range of 35-50 kg. The variability of the derived sulfur amino acids (SAS) efficiency coefficient (Csas) ranged between 0.64... 0.91 based on the SAS efficiency of casein as a standard. There was an analogous differentiation for the derived requirement values on the basis of the analysed methionine/cystine values of the proteins. For a protein retention of 100 g/day and a live weight of 40 kg, 6.2g methionine/cystine was ascertained based on the highest SAS efficiency (Csas = 1) as yet.     

精氨酸营养(一):精氨酸族氨基酸在猪营养与生产中的重要作用<上篇>

精氨酸、谷氨酰胺、谷氨酸、脯氨酸、天冬氨酸、天冬酰胺、乌氨酸和瓜氨酸可在大多数哺乳动物(包括猪)体内通过复杂的器官间代谢进行相互转化.小肠、肾脏和肝脏是这些氨基酸代谢的主要场所,皮质醇则是这些代谢的一个重要调控激素.由于这些氨基酸(除乌氨酸和瓜氨酸之外)通常大量地存在于植物和动物的组织蛋白中,所以养猪生产者习惯上不大关心猪日粮中精氨酸族氨基酸的添加问题.然而,最近的研究结果表明,这些氨基酸在养分代谢和免疫应答上起着重要的调控作用,从而会影响猪的饲料利用率.精氨酸和谷氨酸就是其中的典型代表,它们具有明确的功能,因此被广泛地应用于猪肉生产中.由瓜氨酸在小肠中合成减少所引起的精氨酸缺乏,是限制哺乳仔猪获得最佳生长性能的主要因素.酶学和代谢学研究结果均表明,对于7～21日龄哺乳仔猪而言,肠上皮细胞线粒体内N-乙酰谷氨酸的生物利用率低下应为通过谷氨酸和脯氨酸合成瓜氨酸受到阻碍负责.因此,无论在日粮中添加精氨酸还是口服N-胺基甲基麸胺酸(N-carbamylglutamate,N-乙酰谷氨酸的一种稳定的代谢类似物)都能提高哺乳仔猪的肌肉蛋白合成率和增重.此外,在早期断奶的仔猪日粮中添加谷氨酸已可防治其小肠萎缩.并且提高了仔猪的生长性能.值得注意的是,在妊娠30～114d的小母猪日粮中添加精氨酸,也会显著地提高产活仔数和窝初生重.大规模地使用饲料级精氨酸和谷氨酰胺为提高全球养猪生产的动物健康和养分利用率展现了广阔的前景.     

精氨酸营养(一):精氨酸族氨基酸在猪营养与生产中的重要作用<下篇>

上期回顾:上期主要介绍了母猪乳汁中精氨酸族氨基酸的含量及其在哺乳母猪乳腺组织中的代谢,和谷酰胺和胱氨酸在仔猪营养中的作用. 4 精氨酸在新生仔猪营养中的作用 4.1 精氨酸合成对维持其在哺乳仔猪体内的自动动态平衡所起的关键作用     

精氨酸族氨基酸在猪营养在生产中的重要作用〈下篇〉

4精氨酸在新生仔猪营养中的作用 4．1精氨酸合成对维持其在哺乳仔猪体内的自动动态平衡所起的关键作用 对于幼龄仔猪来说，精氨酸是一种必需氨基酸（Southern和Baker，1983；Roth等，1995；Urschel等，2006）。虽然精氨酸可经鸟氨酸循环在肝脏中合成，但由于能够快速水解精氨酸的胞质精氨酸酶具有极高的活性（Wu和Morris，1998），使肝脏不能实现精氨酸的净合成（Urschel等，2005）。     

Transmission of classical swine fever. A review

Classical swine fever (CSF) is one of the most important viral pig diseases. Basic measures to control epidemics of CSF comprise eradication of infected herds and preventive emptying of herds at risk. Identification of these herds at risk is based on knowledge of the different transmission routes of the virus. Direct transmission of CSF is undoubtedly the most efficient way of CSF virus transmission. Data on indirect transmission are variable and often equivocal. Various indirect transmission routes like swill feeding, wild boar and artificial insemination are well described, and the importance is beyond discussion. Mechanical transmission via vehicles and persons are categorized as very important based upon epidemiological research, whereas in experiments they can only be reproduced under worst case conditions. The role of arthropods, birds, rodents, and other animals in the spread of CSF virus remains doubtful. Active transmission by these has never been demonstrated and also very sparse indications for mechanical transmission are available. Also the role of airborne transmission remains debated. However epidemiological as well as experimental data indicate that airborne spread over short distances is probable.