The purpose of this study was to evaluate the effects of feeding two different levels of benzoic acid (BA) and three different levels of inulin (IN) on weaner pig performance, coefficient of apparent ileal digestibility of total nitrogen (CAIDN), small intestinal structure, diversity of caecal microbiota, indices of bacterial fermentation, incidence of post-weaning diarrhea (PWD) and enterotoxigenic Escherichia coli (ETEC) shedding. Ninety-six female pigs (Large White × Landrace) aged 21 ± 3 d and weighing 5.9 ± 0.08 kg (mean ± S.E.) were used in a 2 × 3 factorial experiment, with the respective factors being supplementation of BA (0 and 5 g/kg; referred to as BA0 and BA5, respectively) and (or) IN (0, 40 and 80 g/kg; referred to as IN0, IN40 and IN80, respectively) in the diet. In week 2, pigs eating BA5 + IN80 gained as an average 53 and 50 g/d more weight (P=0.044) than pigs eating the BA0 + IN80 and BA5 + IN0 diets, respectively. Benzoic acid increased average daily gain (ADG) and feed intake (FI) in the third week after weaning (P=0.006 and P=0.037, respectively) and overall (P=0.026 and P=0.024, respectively). Feeding the BA-supplemented diets increased the CAIDN (P=0.003) and villous height (P=0.05), and tended to improve the villlus:crypt ratio (P=0.10). A significant BA x IN interaction increased bacterial diversity in digesta (P=0.005) and the proportions of propionic acid (P=0.028) in the caecum. Inulin supplementation decreased (P=0.001) the proportions of acetic and increased (P=0.001) the proportions of valeric acids in the caecal and proximal colon digesta. Benzoic acid tended to decrease levels of lactic acid (LA; P=0.063) and proportions of branched-chain fatty acids (BCFA) in the caecal (P=0.091) and proximal colon (P=0.099) digesta. The molar proportion of BCFA in the proximal colon was influenced by IN (P=0.012), with highest proportions found in pigs eating BA0 + IN80 and lowest proportions found in pigs eating BA5 + IN40 diets. The incidence of PWD was sporadic, low and unaffected by diet. These data imply that feeding weaner pigs a BA-supplemented diet has potential to improve ADG, FI, CAIDN and gastrointestinal development, and increase bacterial diversity in the caecum.

为验证日粮中添加苯甲酸和菊糖可以降低氨氮(NH3-N)的排泄这一假设。试验采用2×3试验设计,苯甲酸添加水平为0和5 g.kg-1,菊糖添加水平为0、40和80g.kg-1。21±3日龄、体重5.87±0.077 kg的大白×长白二元杂交公猪96头随机分配到各处理组中。试验猪采用单笼饲养,试验期为3周。在试验第14和21天每个处理选择6头猪采集血液(前后采集的猪只固定),在试验第21天屠宰仔猪并收集食糜、尿液和粪样。日粮中只添加苯甲酸降低了粪和尿液总的氨氮浓度(P=0.05),而菊糖增加了粪便氨氮的排泄量(P=0.001),降低了尿液氨氮的排泄量(P=0.001)。且日粮中添加苯甲酸降低了尿液(P=0.001)和粪便的(P=0.033)pH,日粮中添加苯甲酸(P=0.001)或菊糖(P=0.008)均降低了血浆尿素水平。日粮中添加苯甲酸和菊糖之间并不存在互作效应。结果表明,日粮中添加苯甲酸和菊糖可以通过不同的机制降低氨氮的排泄,原因可能是有降低粪便的pH和微生物数量以及改变细菌的代谢活性。

Abstract The most effective way to control post-weaning diarrhoea (PWD) in piglets remains the use of prophylactic and for therapeutic levels of antibiotics. However, increasing concerns about the transfer of antibiotic-resistant bacteria to humans via the use of antibiotic growth promoters (AGP) in animals have led to the ban in the European Union of all AGPs in pig diets from 1 January 2006. Consequently, it is important to develop ways of controlling the weaning transition in piglets without the use of antibiotic feed additives. The scope of this review is an examination of the adaptation of the gastrointestinal tract to weaning and the mechanisms of PWD. Furthermore, the addition of organic acids, prebiotics and probiotics as feed additives as well as dietary carbohydrate and protein modulation to minimize PWD will be discussed. Based on the available literature, organic acids can increase post-weaning performance significantly even though it is not possible at times to recognize the most effective dosage, acid or combination of acids. In some cases, prebiotics can increase the numbers of possible beneficial bacteria such as Lactobacillus spp. and Bifidobacterium spp. in the gastrointestinal tract; however, there is little evidence of this then improving performance and health. The data defining the benefits of probiotics are equivocal; however, at least some probiotics seem to be able to improve performance of nursery pigs. Lowering dietary protein content for a short period post-weaning will probably reduce PWD and improve intestinal health of the piglets but performance is compromised if essential amino acid levels and/or ratios are reduced below requirement.

This study investigated the effects of weaning age, diet, and classification of piglets as ‘eaters’ or ‘non eaters’ of creep feed in lactation, on production and diarrhoea after weaning. Four antimicrobial-free diets were offered in lactation and for 14 days after weaning: (i) wheat–soy based diet with animal and vegetable (‘mixed’) protein sources (COMM), (ii) heat-processed rice (HPR) with barley hulls and potato starch and mixed protein sources (RBHPS), (iii) HPR with sugar-beet pulp and mixed protein sources (RSBP), and (iv) HPR with mixed protein sources (R). Piglets were individually examined for diarrhoea daily for 14 days after weaning, and antibiotic treatments were individually recorded. Faecal swabs were taken on day 10 after weaning and scored for β-haemolytic Escherichia coli. There were significant main effects of weaning age and diet (both P<0.001) on daily gain between weaning and 14 days after weaning. Pigs weaned later grew 50 g/day more than pigs weaned earlier, and pigs fed the COMM diet grew slower than pigs fed the rice-based diets. The number of antibiotic treatments was influenced by diet (P<0.001), with most treatments (2.1) given to pigs fed the diet RBHPS. Faecal score was influenced by a weaning age and diet interaction (P<0.01). There was no correlation (P>0.05) between the number of antibiotics treatments and the E. coli score.

Th is stud y investigated the effects of w eaning age, diet, and classification of piglets as OeatersO or Ono n eatersO of cree p fee d inlactation, on prod uc tion an d diarrhoea after w eaning. F our antim icrobial-free diets we re offered in lactation an d for 14 days afterwe aning: (i) w heatÐ so y based diet wi th anim al and vegetable (Omi xe dO) protein so urces (C O M M ), (ii) heat-processed rice (H P R ) w ithbarley hu lls and po tato starch an d m ixed protein sources (R B H P S ),(iii) H P R wi th su ga r-be et pu lp and m ixed protein sources (R SB P) ,and (iv) H P R wi th mi xe d protein so urces (R ). P iglets we re individually ex am ined for diarrhoea da ily for 14 days after w eaning, andantibiotic trea tm en ts we re individually recorded. F aecal sw abs we re take n on day 10 after w eaning and scored for ! -hae mo lyticEs cherichia coli. T here we re significan t m ain effec ts of we aning age and diet (bo th P b 0.001) on daily gain betwe en we an ing and14 days after w eaning.P igs w eane d later grew 50 g/day m ore than pigs w eaned earlier,and pigs fed the CO M M dietgrew slow er thanpigs fed the rice -based diets.Th e num ber of antibiotic treatm ents w as influenced by diet(P b 0.001),w ith m osttreatm ents (2.1) given topigs fed the diet RB HP S . Fa ec al score w as influenced by a w eaning age and diet interaction (P b 0.01). Th ere w as no co rrelation(P N 0.05) betw een the num be r of antibiotics treatm ents an d the E. co liscore.© 2007 Elsevier B.V . All rights reserved.

The effects of weaning age, type of creep diet and the classification of piglets as ‘eaters’ or ‘non eaters’ of creep feed on weight gain to weaning were examined. Four antimicrobial-free diets were offered from day 14 of lactation: (i) wheat-soy based diet with animal and vegetable (‘mixed’) protein sources (COMM), (ii) heat-processed rice (HPR) with barley hulls and potato starch and mixed protein sources (RBPS), (iii) HPR with sugar-beet pulp and mixed protein sources (RSBP), and (iv) HPR with mixed protein sources (R). Pigs were weaned at an average of either 27 (early) or 33 (late) days of age. A dye (indigo carmine) was added to each diet at day 24 of lactation in both groups to classify piglets as ‘eaters’ or ‘non eaters’ of creep feed, based on appearance or non-appearance, respectively, of dye in faeces. Pigs weaned late weighed 1.4 kg more (P<0.001). Weaning age interacted with diet type and eating classification for weaning weight (P<0.001). Of the 1067 piglets where classification of the faecal dye was possible, 829 (77.7%) were ‘eaters’ and 238 (22.3%) were ‘non eaters’. This qualitative estimate of creep feed consumption did not influence weight gain to weaning (P>0.05).

Over 90 distinct single site mutations in the enzyme copper-zinc superoxide dismutase (CuZnSOD, SOD1) have been individually linked to the inherited (familial) form of the neurodegenerative disease amyotrophic lateral sclerosis (FALS, known also as Lou Gehrig's disease).We recently determined the Xray structure of the FALS CuZnSOD mutant D125H to 1.4 Å resolution using synchrotron radiation and single-wavelength anomalous diffraction (SAD) phasing methods.The nearly metal-free, 'as isolated' D125H crystallized from a solution containing 10 mM zinc sulfate.Surprisingly, zinc is unambiguously observed in both the copper-and the zinc-binding sites.The zinc in the zinc-binding site is coordinated in a fashion identical to that of the wild type protein.The zinc in the copper site is tetrahedrally coordinated to His46, His48, His120, and an oxygen atom of a sulfate anion.Another sulfate oxygen atom accepts hydrogen bonds from the epsilon and guanidinium nitrogens of Arg143, the residue primarily responsible for electrostatic guidance of the superoxide substrate into the active site channel.This region likely serves as a binding site for other anions such as bicarbonate that in turn participate in the radical inactivation of CuZnSOD, or in the oxidation of exogenous substrates as previously observed in multiple EPR studies performed on the native and mutant enzymes.The D125H structure also reveals little electron density for the region from residues 127 to 140 that is important in maintaining the structural integrity of SOD1, in directing the substrate to the active site, and in sterically preventing large non-native substrates from gaining access to the catalytic copper ion.

Trends for a reduction in the use of dietary antibiotic growth promoters have caused increased interest in the use of alternative feed additives to maintain 'gut health' after weaning. Oligofructose and inulin are 'prebiotic' fructan-containing carbohydrates purported to enhance 'gut health' in newly-weaned pigs by altering microbial diversity (Konstantinov, et al., 2003). However, their effects using a challenge model of post-weaning colibacillosis (PWC) have never been examined. The aim of the present study was to compare the separate and combined effects of oligofructose and inulin supplementation on the occurrence of diarrhoea and the weight performance in piglets experimentally challenged with enterotoxigenic E. coli (ETEC).