The effect of organic acids on the control of porcine post-weaning diarrhoea

Comparison of single and blend acidifiers as alternative to antibiotics on growth performance, fecal microflora, and humoral immunity in weaned piglets

The banning of the use of antibiotics as feed additive has accelerated investigations of alternative feed additives in animal production. This experiment investigated the effect of pure citric acid or acidifier blend supplementation as substitute for antibiotic growth promoters on growth performance, fecal microbial count, and humoral immunity in weaned piglets challenged with Salmonella enterica serover Typhimurium and Escherichia coli KCTC 2571. A total of 60 newly weaned piglets (crossbred, 28-d-old; average 8 kg initial weight) were randomly assigned to four dietary treatments in a completely randomized design. Dietary treatments included NC (negative control; basal diet), PC (positive control; basal diet+0.002% apramycin), T1 (basal diet+0.5% pure citric acid), and T2 (basal diet+0.4% acidifier blend). All piglets were orally challenged with 5 mL of culture fluid containing 2.3×10⁸ cfu/mL of E. coli KCTC 2571 and 5.9×10⁸ cfu/mL of S. typhimurium at the beginning of the experiment. The PC group showed the highest ADG and ADFI, whereas gain:feed was improved in the PC and T1 group (p<0.05). All dietary treatments showed significant reduction in fecal counts of Salmonella and E. coli, compared to NC (p<0.05), with PC being better than T1 and T2. Significant elevation in fecal Lactobacillus spp. counts was shown by treatments with T1, T2, and PC, whereas Bacillus spp. counts were increased by treatment with T1 and T2 compared to NC and PC diet (p<0.05). Serum IgG concentration was increased by T1 diet (p<0.05), whereas IgM and IgA were not significantly affected by any of the dietary treatments (p>0.05). From these above results, it can be concluded that, as alternatives to antibiotics dietary acidification with pure citric acid or acidifiers blend did not fully ameliorate the negative effects of microbial challenges in respect of growth performance and microbial environment, however improved immunity suggested further research with different dose levels.

Effects of dietary combinations of organic acids and medium chain fatty acids on the gastrointestinal microbial ecology and bacterial metabolites in the digestive tract of weaning piglets

Organic short and medium chain fatty acids are used in diets for piglets because they have an impact on the digestive processes and the intestinal microbiota. In this study, 48 pens (2 piglets/pen) were assigned randomly to 4 diets, without additive (control), with organic acids (OA; 0.416% fumaric and 0.328% lactic acid), with medium chain fatty acids (MCFA; 0.15% caprylic and capric acid), and a combination of OA and MCFA, to assess changes in the gastrointestinal microbiota with 12 pens per diet. Eight to nine piglets from each group were euthanized after 4 wk. Organic acids, MCFA, and pH in the digesta were determined and the intestinal microbiota was quantified by real-time PCR. The different diets had no effect on the growth performance. Concentration of added fumaric acid was below the detection limit in the upper small intestine whereas the concentration of lactic acid in the digesta was not affected by the treatments. The added MCFA was recovered in the MCFA treated groups in the stomach, but the concentrations declined in the upper small intestine. Concentration of short chain fatty acids was reduced in the colon digesta in piglets fed diets with OA compared with those fed unsupplemented diets (P = 0.029). The MCFA resulted in a pH reduction of the digesta, likely because of the effect on bacterial acid production. The addition of OA increased cell counts of Bacteroides-Porphyromonas-Prevotella group and clostridial clusters XIVa, I, and IV in the stomach, the clostridial cluster XIVa in the jejunum, and Bacteroides-Porphyromonas-Prevotella in the ileum and reduced counts of Streptococcus spp. in the colon (P < 0.05). The MCFA induced only minor changes in the gastrointestinal microbiota but increased cell counts for the Escherichia-Hafnia-Shigella group in the jejunum and the clostridial cluster XIVa in the colon digesta (P < 0.05). In the colon of piglets fed diets with organic OA, reduced mean cell counts of STb (est-II) positive Escherichia coli were found. In conclusion, OA and MCFA had effects on the intestinal microecology in piglets. The decrease of the intestinal pH and the reduction of E. coli virulence genes by OA could make the combination of short chain fatty acids and MCFA as interesting gut flora modifiers, which can eventually prevent postweaning diarrhea.

Effects of sodium butyrate on growth performance, haematological and immunological characteristics of weanling piglets

The experiment was conducted to study the effects of sodium butyrate (SB) on growth, haematological and immunological characteristics in weanling pigs. A total of 100 male piglets (Duroc×Landrace×Yorkshire) with a body weight of 8.0 ± 0.2 kg weaned at the age of 28 days were randomly assigned to two treatments with five replicates and 10 pigs per replicate. Piglets received a basal diet (control group) or diets supplemented with 1000 mg/kg SB. The feeding trial lasted for 21 days. The results showed that dietary SB significantly decreased (p < 0.05) diarrhoea incidence of weaned piglets, but did not affect (p > 0.05) the average daily feed intake (ADFI), average daily gain (ADG) and feed to gain (F/G). Furthermore, piglets fed dietary SB had higher (p < 0.05) serum concentrations of glucose and triglycerides and lower (p < 0.05) serum concentrations of urea nitrogen, cortisol, D-lactic acid and diamine oxidase when compared with the control group. However, dietary SB did not affect concentrations of serum albumin, total protein, insulin and glucagon (p > 0.05). There were no significant (p > 0.05) treatment effects on serum IgA and IgM, whereas serum IgG concentration and IgA+ cell count in jejunum from pigs fed SB were significantly higher (p < 0.05) than in those given the basal diet. In conclusion, the present study indicated that dietary SB significantly decreased diarrhoea incidence of weaned piglets and increased the efficiency of nitrogen utilization. Also, dietary SB could regulate and enhance the immune function of piglets by increasing the serum IgG concentration and IgA+ cell count in jejunum. Our results suggest that SB may reduce some of the adverse effects of weaning stress and play an important role in maintaining the integrity of intestinal mucosa.

Gastrointestinal health and function in weaned pigs: a review of feeding strategies to control post-weaning diarrhoea without using in-feed antimicrobial compounds

For the last several decades, antimicrobial compounds have been used to promote piglet growth at weaning through the prevention of subclinical and clinical disease. There are, however, increasing concerns in relation to the development of antibiotic-resistant bacterial strains and the potential of these and associated resistance genes to impact on human health. As a consequence, European Union (EU) banned the use of antibiotics as growth promoters in swine and livestock production on 1 January 2006. Furthermore, minerals such as zinc (Zn) and copper (Cu) are not feasible alternatives/replacements to antibiotics because their excretion is a possible threat to the environment. Consequently, there is a need to develop feeding programs to serve as a means for controlling problems associated with the weaning transition without using antimicrobial compounds. This review, therefore, is focused on some of nutritional strategies that are known to improve structure and function of gastrointestinal tract and (or) promote post-weaning growth with special emphasis on probiotics, prebiotics, organic acids, trace minerals and dietary protein source and level.

Ácido fumárico e sua combinação com ácido lático ou propionato de cálcio em dietas de leitões recém-desmamados

Avaliou-se o efeito da adição dos ácidos fumárico, lático e propionato de cálcio ou suas combinações sobre o desempenho, pH estomacal, pH duodenal, morfologia e morfometria do intestino delgado de leitões desmamados aos 15 dias de idade. Foram utilizados 180 leitões, 90 machos castrados e 90 fêmeas, com média de peso inicial de 4,78±1,19kg, distribuídos em delineamento de blocos ao acaso. Utilizaram-se cinco tratamentos: T1 - ração controle (RC); T2 - RC + 0,5% de ácido fumárico; T3 - RC + 0,5% de ácido fumárico + 1,0% de propionato de cálcio; T4 - RC + 0,5% de ácido fumárico + 1,0% de ácido lático; T5 - RC + 0,5% de ácido fumárico + 0,5% de propionato de cálcio + 0,5% de ácido lático, com seis repetições e seis animais por unidade experimental. Não houve influência (P>0,05) dos tratamentos sobre o ganho de peso diário (GPD), consumo de dieta diário (CRD) e conversão alimentar (CA). Quanto ao epitélio intestinal, não houve diferenças (P>0,05) entre tratamentos em relação à altura do epitélio do duodeno, jejuno e íleo. Não houve efeito dos tratamentos (P>0,05) sobre o pH do estômago e do jejuno. A inclusão do ácido fumárico não influenciou o desempenho dos leitões.

Alimentação de porcas lactantes com dietas contendo silagem de grãos úmidos de milho e ácido fumárico

Estudou-se o efeito de dietas elaboradas com silagem de grãos úmidos de milho e ácido fumárico sobre os desempenhos de porcas lactantes e suas leitegadas. Foram utilizadas 20 porcas de genética comercial em um delineamento de blocos ao acaso com quatro tratamentos - dieta basal (DB), elaborada a cada 24h; DB + 0,3% de ácido fumárico - (AF); DB + 0,6% AF; e DB + 0,9% de AF, e cinco repetições. As dietas contendo ácido fumárico foram elaboradas a cada 48 horas. O consumo médio diário da dieta das porcas lactantes foi de 7,42kg de matéria natural e não houve diferença (P>0,05) entre os tratamentos. A adição de 0,9% de ácido fumárico às dietas reduziu (P<0,01) em 6% o pH do leite em relação à dieta-basal. A média de ganho diário e a média de peso dos leitões não diferiram (P>0,05) entre os tratamentos. A adição de ácido fumárico às dietas não alterou os desempenhos de porcas lactantes e de suas leitegadas. A adição de ácido fumárico às dietas de lactação elaboradas com silagem de grãos úmidos de milho reduziu o pH do leite e aumentou a frequência de fezes normais dos leitões lactentes.

Risk factors for post-weaning diarrhoea on piglet producing farms in Finland

Background

Post-weaning diarrhoea (PWD) is a significant gastrointestinal disease in pigs. It is considered a multifactorial disease associated with proliferation of enterotoxigenic Escherichia coli in the intestinal tract of affected pigs. The aim of this study was to analyse risk factors related to the occurrence of PWD on Finnish piglet producing farms.

Methods

The data of a follow-up study of 73 conventional piglet producing farms was used in the case-control study. The selection of the 41 PWD case and 28 control farms was based on the use of antimicrobials for treating diarrhoea in weaned pigs and the answers related to the occurrence of diarrhoea after weaning in the questionnaire. Four intermediate farms were excluded from the statistical analysis.

Altogether 39 factors related to herd characteristics, weaner pig management and pig health were studied. The median number of sows was 59.0 (IQR = 44.0; 74.5) and 52.5 (IQR = 36.8; 61.5) on the case and the control farms, respectively.

The significances of the univariable associations between the explanatory variables and the outcome variable were tested, and in the multivariate analysis quasibinomial generalized linear models were applied.

Results

An increased risk of PWD was associated with the regimen of twice a day feeding and feed restriction after weaning (P = 0.02; compared to feeding three or more meals a day or the use of ad libitum feeding) and with a higher number of sows on the farm (P = 0.02; risk increasing with increasing number of sows). Automatic temperature control was associated with a decreased risk of PWD (P = 0.03; compared to manual temperature control).

Conclusion

Twice a day feeding of newly-weaned pigs should be avoided if the amount of feed given is restricted. Variation in ambient temperature should be minimized in housing of newly-weaned pigs and this can be achieved by using automatic temperature control. With increasing number of sows in the herds the risk of PWD increases and more attention should be paid to prevention of post-weaning diarrhoea.

Dietary manipulation post weaning to improve piglet performance and gastro-intestinal health

Two experiments were conducted to investigate the use of dietary manipulation as a means of improving piglet post-weaning performance and gastro-intestinal health. In experiment 1, 144 piglets (24 days old) in a 3 × 2 factorial arrangement were offered diets containing 65, 170 and 280 g lactose per kg with or without lactic acid (16 g/kg) for 28 days. In experiment 2, 20 piglets (24 days old) (in a 2 × 2 factorial arrangement were offered the following diets for 7 days and then sacrificed: T1) basal diet; T2) basal diet + 15 g inulin per kg; T3) basal diet + 16 g lactic acid per kg and T4) basal diet + 15 g inulin per kg + 16 g lactic acid per kg. After slaughtering, tissue samples were taken from the duodenum, jejunum and ileum for morphological measurements. Digesta samples were taken from the ileum, caecum and colon for microbiology and volatile fatty acid analysis. In experiment 1, pigs offered diets containing lactic acid had improved daily gain (P< 0·01) and food efficiency (P< 0·05) from days 0 to 7 compared with pigs offered diets containing no lactic acid. There was a linear increase (P< 0·05) in average daily gain (ADG) from days 0 to 28 and a linear decrease in faecal pH (P< 0·01) with increasing lactose levels. There was a quadratic effect of lactose on food conversion ratio from days 0 to 28 (P< 0·05). In experiment 2, there was a significant interaction between inulin and lactic acid in villous height in the jejunum (P< 0·001) and the concentrations of lactobacilli (P< 0·1) andE. coli(P< 0·05) in the colon. The inclusion of inulin and lactic acid resulted in a significant increase in villous height compared with the inulin only diet (P< 0·001). However, lactic acid had no effect on villous height in pigs offered diets without inulin supplementation. The inclusion of lactic acid and inulin caused a significant increase in both lactobacilli andE. coliconcentrations compared with the inulin only diets (P< 0·05). However, neither inulin nor lactic acid had an effect on lactobacilli andE. colinumbers in isolation of the other. In conclusion, in experiment 1, lactic acid improved performance in the 1st week post weaning. There was a linear increase in ADG with increasing lactose levels. In experiment 2, the combination of lactic acid and inulin increased villous height in the jejunum and concentrations of lactobacilli andE. coliin the colon.

Performance, intestinal microflora, and wall morphology of weanling pigs fed sodium butyrate

Adding organic acids to piglet diets is known to be helpful in overcoming postweaning syndrome, and butyric acid is known to be the main energy source for the epithelial cells of the large intestine and the terminal ileum. This study investigated the effect of sodium butyrate (SB) on in vitro and in vivo swine microflora, piglet growth performance, and intestinal wall morphology. During a 24-h in vitro cecal fermentation, total gas production and maximal rate of gas production were reduced linearly by SB (P < 0.001). Ammonia in cecal liquor was increased linearly by SB after 4, 8, and 24 h of fermentation (P < 0.001). In the in vivo study, 48 piglets housed in individual crates were allotted to 4 treatment groups (12 animals per treatment) for 6 wk. Piglets received a basal diet with a) no addition (control), or with SB at b) 1,000 ppm, c) 2,000 ppm, or d) 4,000 ppm. After 6 wk, 6 animals per treatment were killed, and samples of intestinal content and mucosa were collected. Sodium butyrate did not improve the animal growth performance. In the cecum, SB increased pH and isobutyric acid concentration (linear, P < 0.05) and tended to increase ammonia concentration (P = 0.056). Intestinal counts of clostridia, enterobacteriaceae, and lactic acid bacteria as well as intestinal mucosal morphology were not affected by feeding SB. This study showed that SB influenced the cecal microflora in an in vitro system, reducing the total gas production but increasing ammonia concentrations. When fed to piglets, SB did not improve the animal growth performance, increased cecal pH, and tended to increase cecal ammonia concentrations. Further studies will be needed to better understand the mechanisms underlying the effects observed when SB is fed to piglets.

Lipid microencapsulation allows slow release of organic acids and natural identical flavors along the swine intestine1,2

The purpose of the present work was to investigate the in vivo concentrations of sorbic acid and vanillin as markers of the fate of organic acids (OA) and natural identical flavors (NIF) from a microencapsulated mixture and from the same mixture non-microencapsulated, and the possible consequences on the intestinal microbial fermentation. Fifteen weaned pigs were selected from 3 dietary groups and were slaughtered at 29.5 +/- 0.27 kg of BW. Diets were (1) control; (2) control supplemented with a blend of OA and NIF microencapsulated with hydrogenated vegetable lipids (protected blend, PB); and (3) control supplemented with the same blend of OA and NIF mixed with the same protective matrix in powdered form but without the active ingredient coating (non-protected blend, NPB). Stomach, cranial jejunum, caudal jejunum, ileum, cecum, and colon were sampled to determine the concentrations of sorbic acid and vanillin contained in the blend and used as tracers. Sorbic acid and vanillin were not detectable in pigs fed the control, and their concentrations were not different in the stomach of PB and NPB treatments. Pigs fed PB showed a gradual decrease of the tracer concentrations along the intestinal tract, whereas pigs fed NPB showed a decline of tracer concentration in the cranial jejunum and onwards, compared with the stomach concentrations. Sorbic acid and vanillin concentrations along the intestinal tract were greater (P = 0.02) in pigs fed PB compared with pigs fed NPB. Pigs fed PB had lower (P = 0.03) coliforms in the caudal jejunum and the cecum than pigs fed the control or NPB. Pigs fed the control or PB had a greater (P = 0.03) lactic acid bacteria plate count in the cecum than pigs fed NPB, which showed a reduction (P = 0.02) of lactic acid concentrations and greater (P = 0.02) pH values in the caudal jejunum. The protective lipid matrix used for microencapsulation of the OA and NIF blend allowed slow-release of both active ingredients and prevented the immediate disappearance of such compounds upon exiting the stomach.

A continuous dietary supply of free calcium formate negatively affects the parietal cell population and gastric RNA expression for H+/K+-ATPase in weaning pigs

Baby formula acidification can be used to reduce diarrhea. Calcium formate is a dietary acidifier frequently used in animal weaning diets; it is also a source of available calcium. Gastric acidification reduces gastrin release and hydrochloric acid (HCl) secretion. To study the medium-term effects on fundic gastric mucosa, we fed weaning pigs control diets or diets supplemented with free or fat-protected calcium formate. We evaluated the following: 1) the number of HCl-secreting parietal cells, by immunohistochemistry using an antibody against H(+)/K(+)-ATPase; 2) the number of enteroendocrine cells immunohistochemically stained with chromogranin A (CGA), somatostatin, and histamine (HIS); and 3) the expression of the H(+)/K(+)-ATPase gene, by real-time RT-PCR in the oxyntic mucosa. Cells co-staining for CGA and HIS were defined as enterochromaffin-like (ECL) cells. Pigs fed calcium formate had fewer parietal cells and a lower expression of the H(+)/K(+)-ATPase gene than the controls (P < 0.05). This reduction did not occur in pigs fed fat-protected calcium formate. Somatostatin immune-reactive cells were also more numerous in pigs fed free calcium formate than in controls (P < 0.05). The number of ECL cells was not affected. Using covariance analysis, the number of parietal cells explained part of the differences in the expression of H(+)/K(+)-ATPase gene (positive correlation, r = 0.385, P < 0.01), and excluded the statistical significance of the diet. In the future, the effects on the oxyntic mucosa should be checked when the diet supplemented with calcium formate is discontinued. Furthermore, a reduction in the number of parietal cells could impair the absorption of vitamin B-12 due to a reduced secretion of the intrinsic factor by these cells.

Selected culturable enteric bacterial populations are modified by diet acidification and the growth promotant Tylosin

AIMS

To determine the effect of diet acidification and an in-feed antibiotic growth promotant (Tylosin, Ty) on selected culturable bacterial populations in the gastrointestinal tract (GIT) of mice.

METHODS AND RESULTS

Female C57Bl mice were given a standard diet supplemented with Acid Pak (AP) or Ty in the drinking water. After 21 days, lumen and adherent populations of Enterobacteriaceae, enterococci/streptococci, and lactic acid bacteria (LAB) from the ileum, caecum, colon and faeces were enumerated. General intestinal health was assessed by the frequency of haemolytic bacteria in the different intestinal compartments. Contrary to expectations, AP and Ty significantly increased haemolytic bacteria in the lumen of the caecum and colon (P<0.05). The small but significant growth-enhancing effect of Ty (P<0.05) was associated with decreases in enterococci/streptococci and surprisingly, LAB, as well as increases in coliforms. AP, which failed to improve growth rates, reduced coliforms, had limited effects on enterococci/streptococci, and specifically failed to promote the growth of LAB populations in all intestinal compartments. Ty supplementation was also associated with a significant increase in macrolide-resistant enterococci throughout the GIT.

CONCLUSIONS

Dietary acidification is less effective than Ty in modulating the population dynamics of selected culturable populations of enteric bacteria.

SIGNIFICANCE AND IMPACT OF THE STUDY

The mouse can provide a useful experimental model to examine the effects of new dietary supplements, formulations or regimes on changes in microbial population dynamics, including monitoring for antibiotic resistance.

Escherichia coli in postweaning diarrhea in pigs: an update on bacterial types, pathogenesis, and prevention strategies

Escherichia coli is one of the most important causes of postweaning diarrhea in pigs. This diarrhea is responsible for economic losses due to mortality, morbidity, decreased growth rate, and cost of medication. The E. coli causing postweaning diarrhea mostly carry the F4 (K88) or the F18 adhesin. Recently, an increase in incidence of outbreaks of severe E. coli-associated diarrhea has been observed worldwide. The factors contributing to the increased number of outbreaks of this more severe form of E. coli-associated diarrhea are not yet fully understood. These could include the emergence of more virulent E. coli clones, such as the 0149:LT:STa:STb:EAST1:F4ac, or recent changes in the management of pigs. Development of multiple bacterial resistance to a wide range of commonly used antibiotics and a recent increase in the prevalence and severity of the postweaning syndromes will necessitate the use of alternative measures for their control. New vaccination strategies include the oral immunization of piglets with live avirulent E. coli strains carrying the fimbrial adhesins or oral administration of purified F4 (K88) fimbriae. Other approaches to control this disease include supplementation of the feed with egg yolk antibodies from chickens immunized with F4 or F18 adhesins, breeding of F18- and F4-resistant animals, supplementation with zinc and/ or spray-dried plasma, dietary acidification, phage therapy, or the use of probiotics. To date, not a single strategy has proved to be totally effective and it is probable that the most successful approach on a particular farm will involve a combination of diet modification and other preventive measures.