Antibiotic use in animal feed and its impact on human healt

Dietary High Zinc Oxide Modulates the Microbiome of Ileum and Colon in Weaned Piglets

Dietary zinc oxide (ZnO) at pharmacological level has been widely used to prevent and treat diarrhea in weaning piglets. Despite its importance for promoting animal health and performance, the influence of microbiome profiles in intestinal tracts by ZnO needs to be comprehensively investigated. In this study, we conducted a comparative microbial community analysis in the ileum and colon of piglets fed by either control diet, high ZnO (3,000 mg/kg) supplement or antibiotics (300 mg/kg chlortetracycline and 60 mg/kg colistin sulfate) supplement. Our results showed that both high dietary ZnO and in-feed antibiotics supplementations significantly increased 5 phyla of Spirochaetes, Tenericutes, Euryarchaeota, Verrucomicrobia, TM7, and reduced 1 phyla of Chlamydiae in ileal digesta. The relative abundance of opportunistic pathogens Campylobacterales were decreased while Enterobacteriales were increased in ZnO or antibiotics-supplemented group when compared to the control. In the colon, the phyla Euryarchaeota, the genus Methanobrevibacter, and the species Methanobrevibacter smithii were drastically increased by high dietary ZnO supplementation when compared with other groups. The microbial functional prediction analysis showed that high dietary ZnO and in-feed antibiotics had a higher abundance of transporter pathway enrichment in the ileum when compared with the control. While in the colon high dietary ZnO had a higher abundant enrichment of methane metabolism involving energy supply when compared with other groups. Both high dietary ZnO and antibiotics increased the microbiota diversity of ileal digesta while they decreased the microbiota diversity of the colonic digesta. Collectively, these results suggested that dietary ZnO and in-feed antibiotics supplementations presented similar effect on ileal microbiota, and mainly affected the non-predominant microbiota.

Seasonal variation and removal efficiency of antibiotic resistance genes during wastewater treatment of swine farms

The seasonal variation and removal efficiency of antibiotic resistance genes (ARGs), including tetracycline resistance genes (tetG, tetM, and tetX) and macrolide (ermB, ermF, ereA, and mefA), were investigated in two typical swine wastewater treatment systems in both winter and summer. ARGs, class 1 integron gene, and 16S rRNA gene were quantified using real-time polymerase chain reaction assays. There was a 0.31-3.52 log variation in ARGs in raw swine wastewater, and the abundance of ARGs in winter was higher than in summer. tetM, tetX, ermB, ermF, and mefA were highly abundant. The abundance of ARGs was effectively reduced by most individual treatment process and the removal efficiencies of ARGs were higher in winter than in summer. However, when examining relative abundance, the fate of ARGs was quite variable. Anaerobic digestion reduced the relative abundance of tetX, ermB, ermF, and mefA, while lagoon treatment decreased tetM, ermB, ermF, and mefA. Sequencing batch reactor (SBR) decreased tetM, ermB, and ermF, but biofilters and wetlands did not display consistent removal efficiency on ARGs in two sampling seasons. As far as the entire treatment system is concerned, ermB and mefA were effectively reduced in both winter and summer in both total and relative abundance. The relative abundances of tetG and ereA were significantly correlated with intI1 (p < 0.01), and both tetG and ereA increased after wastewater treatment. This may pose a great threat to public health.

Effects of Lactobacillus acidophilus supplementation on growth performance, nutrient digestibility, fecal microbial and noxious gas emission in weaning pigs

BACKGROUND

Antibiotics used as growth promoters in livestock have been banned in the European Union since 2006. Antibiotics alternatives have focused on probiotics, such as Lactobacillus acidophilus. The concentration of L. acidophilus is considered crucial for obtaining the desired effects. However, limited studies have been conducted to test the dose-dependent effects of L. acidophilus. Therefore, the present study aimed to test the dose-dependent effects of L. acidophilus on growth performance, nutrient digestibility, fecal microbial flora and fecal noxious gas emission in weaning pigs.

RESULTS

Lactobacillus acidophilus supplementation increased (P < 0.05) average daily gain, average daily feed intake, apparent nutrient digestibility of dry matter, nitrogen and gross energy, and Lactobacillus counts compared to the basal diet treatment, and a linear effect (P < 0.05) was observed on those criteria. Escherichia coli counts and NH₃ emission were decreased (P < 0.05) by L. acidophilus supplementation, and a linear effect (P < 0.05) was observed on E. coli counts.

CONCLUSION

These results suggest that L. acidophilus could be used as an antibiotic alternative by improving growth performance, nutrient digestibility and gut balance (i.e. increased Lactobacillus counts and decreased E. coli counts), and decreasing NH3 emission, of weaning pigs. © 2016 Society of Chemical Industry.

The effects of amoxicillin treatment of newborn piglets on the prevalence of hernias and abscesses, growth and ampicillin resistance of intestinal coliform bacteria in weaned pigs

This study investigated the effects of a single amoxicillin treatment of newborn piglets on the prevalence of hernias and abscesses until the age of nine weeks. We also studied whether the treatment was associated with growth and mortality, the need for treatment of other diseases, the proportions of ampicillin resistant coliforms and antimicrobial resistance patterns of intestinal Escherichia coli (E. coli). A total of 7156 piglets, from approximately 480 litters, were divided into two treatment groups: ANT (N = 3661) and CON (N = 3495), where piglets were treated with or without a single intramuscular injection of 75 mg amoxicillin one day after birth, respectively. The umbilical and inguinal areas of weaned pigs were palpated at four and nine weeks of age. At the same time, altogether 124 pigs with hernias or abscesses and 820 non-defective pigs from three pens per batch were weighed individually. Mortality and the need to treat piglets for other diseases were recorded. Piglet faecal samples were collected from three areas of the floors of each pen at four weeks of age. The prevalence of umbilical hernias or abscesses did not differ between the groups at four weeks of age, but it was higher in the CON group than in the ANT group at nine weeks of age (2.3% vs. 0.7%, P < 0.05). Numbers of inguinal hernias and abscesses did not differ between the groups at four or nine weeks of age. The ANT group, when it compared with the CON group, increased the weight gain between four and nine weeks of age (LS means ± SE; 497.5 g/d ± 5.0 vs. 475.3 g/d ± 4.9, P < 0.01), and decreased piglet mortality (19.5% ± 1.0 vs. 6.9% ± 1.0, P < 0.05) and the need to treat the piglets for leg problems (3.4% ± 0.3 vs. 1.9% ± 0.3%, P < 0.01) but not for other diseases by the age of four weeks. The proportion of ampicillin resistant intestinal coliform bacteria and the resistance patterns of the E. coli isolates were not different between the ANT and CON groups. In conclusion, our results showed that the amoxicillin treatment of new-born piglets produced statistically significant effect in some of the parameters studied. However, as these effects were only minor, we did not find grounds to recommend preventive antibiotic treatment. Further, continuous antimicrobial treatment of newborn piglets could negatively influence the development of the normal microbiota of the piglet and promote selection of antimicrobial resistance genes in herds. Therefore we suggest rejection of the use of routine administration of antimicrobial agents at birth.

Effects of dietary supplementation of Saccharomyces cerevisiae fermentation product to sows and their offspring on growth and meat quality

This study evaluated the effects of long term dietary supplementation of Saccharomyces cerevisiae fermentation product (SCFP) in the diets for sows and offspring on growth performance, intestinal morphology, volatile fatty acid production, and carcass characteristics of offspring. Newly weaned pigs (n = 256) were allotted to 4 treatments based on a 2 × 2 factorial arrangement. Each treatment had 8 pens with 8 pigs per pen. First factor was maternal dietary effects (no SCFP, or SCFP at 12.0 and 15.0 g/d through gestation and lactation, respectively) and the second factor was dietary supplementation of SCFP to offspring (no SCFP, or SCFP at 0.2 and 0.1% for nursery and finisher, respectively). Pigs were on a 6-phase feeding program with assigned diets from nursery to slaughter. Body weights (BW) and feeder weights were measured at the end of each phase. On d 5 after weaning, 1 pig per pen was euthanized to evaluate intestinal morphology and volatile fatty acid production. At 115 kg of BW, 1 pig from each pen was slaughtered to measure carcass characteristics. Feeding diets with SCFP to sows or to their offspring had no effect on BW, overall average daily gain (ADG), average daily feed intake (ADFI), and gain-to-feed (G:F) ratio during the nursery or finisher period. Feeding SCFP to sows tended to increase (P = 0.098) cecal butyric acid production in their offspring. Pigs with SCFP tended to have a greater (P = 0.084) concentration of acetic acid but a reduced (P = 0.054) propionic acid in colon digesta than pigs without SCFP regardless of maternal feeding regimen. Loin marbling scores were greater (P = 0.043) in pigs with SCFP than those without SCFP regardless of maternal feeding regimen. Overall, supplementation of SCFP in sow diets did not affect growth performance or intestinal morphology of their offspring. Supplementation of SCFP in diets of offspring from nursery to slaughter had little effect on growth performance. However, inclusion of SCFP from nursery to slaughter improved marbling score possibly by increased acetic acid and butyric acid production in the large intestine.

Ultrasensitive Self-Powered Aptasensor Based on Enzyme Biofuel Cell and DNA Bioconjugate: A Facile and Powerful Tool for Antibiotic Residue Detection

Herein, we reported a novel ultrasensitive one-compartment enzyme biofuel cells (EBFCs)-based self-powered aptasensing platform for antibiotic residue detection. By taking full advantage of the unique features of both EBFCs-based self-powered sensors and aptamers, the as-proposed aptasensing platform has the merits of simple instrumentation, anti-interference ability, high selectivity, and low cost. In this study, DNA bioconjugate, i.e., SiO₂@gold nanoparticles-complementary strand of aptamer (SiO₂@AuNPs-csDNA), was elaborately designed and played a key role in blocking the mass transport of glucose to the bioanode. While in the presence of the target antibiotic, SiO₂@AuNPs-csDNA bioconjugate broke away from the bioanode due to the aptamer recognition of the target. Without the blocking of glucose by the DNA bioconjugate, a significantly elevated open circuit voltage of the EBFCs-based aptasensor was obtained, whose amplitude was dependent on the antibiotic concentration. In addition, this proposed aptasensor was the first reported self-powered aptasensing platform for antibiotic determination and featured high sensitivity owing to the elaborate design of the DNA bioconjugate modified bioanode of EBFC, which was superior to those previously reported in the literature. Furthermore, due to the anti-interference ability and the excellent selectivity of the aptasensor, no special sample pretreatment was needed for the detection of antibiotics in milk samples. Therefore, the proposed EBFCs-based self-powered aptasensor has a great promise to be applied as a powerful tool for on-site assay in the field of food safety.

Reversal of resistance in bacteria underlies synergistic effect of essential oils with conventional antibiotics

The pervasive of bacterial resistance earnestly threaten the prevention and the treatment of infectious diseases. Therefore, scientific communities take precedence over development of new antimicrobial agents. The aim of the study was to determine antimicrobial potency of three North-African essential oils Pituranthos chloranthus, Teucruim ramosissimum and Pistacia lentiscus individually, and in combination with antibiotics, to inhibit the growth of highly resistant clinical pathogen. Bacteria clinically isolated from patients, subsequently, challenged to a panel of drugs to determine the antibiotic-resistance profiles. Drugs displaying clinically irrelevant CMI were subjected to further studies in order to rescue antibiotic actions. Singular activity of essential oils and activity when combined with an antibiotic was hence elucidated. The results obtained highlighted the occurrence of strong antibacterial potential of essential oils when administrated alone. In the interactive experiment essential oils were found highly effective in reducing the resistance of Methicillin-resistant Staphylococcus aureus to amoxicillin, tetracycline, piperacillin, ofloxacin and oxacillin and resistance of Acinetobacter baumannii to amoxicillin and to ofloxacin in interactive manner. Furthermore, the results proved synergism among essential oils and both antibiotics ofloxacin and novobiocin against the Extended-Spectrum Beta-Lactamase producing E. coli (ESBL). Time kill kinetics was performed with a combination of sub-inhibitory concentrations to confirm the efficiency and killing rate of the combination over time. Further, the hypothetical toxicity of essential oils against human keratinocytes HaCat and murine spleenocytes were examined. The chemical composition of essential oils was assessed by GC/MS analysis and the major constituents found were sabinene, limonene, terpinen-4-ol, and β-eudesmol.

Effect of Alchornea cordifolia leaf meal inclusion and enzyme supplementation on performance and digestibility of rabbits

<p>A feeding trial was conducted to study the performance, digestibility and health status of weaner rabbits fed diets including Alchornea cordifolia leaf meal (ALM: 18% crude protein [CP] and 12.9% crude fibre) and supplemented with a multi-enzyme additive (cellulase, xylanase, β-glucanase, α-amylase, protease, lipase). Six experimental diets were arranged factorially: 3 levels of ALM (0, 5 and 10% substituting palm kernel cake: 16.3% CP and 39.1% neutral detergent fibre) combined with 2 levels of enzyme supplementation (0 and 0.35 g/kg). One hundred and eighty healthy, 5-wk-old weaner rabbits of cross-breeds were randomly allotted to 6 dietary treatments (30 rabbits/treatment, 3 rabbits/replicate). Growth rate was not affected (P&gt;0.05) by the main factors (exogenous enzyme and ALM inclusion) and their interactions (13.5 g/d on av.). Daily feed intake and feed conversion ratio decreased (P=0.01) with the ALM inclusion by 8%, but did not affect faecal digestibility. However, enzyme supplementation improved crude protein and crude fibre digestibility (P&lt;0.001) by 6%. In conclusion, ALM inclusion and enzyme supplementation had no adverse effect on the performance and digestibility of rabbits.</p>

Antimicrobial Consumption in Medicated Feeds in Vietnamese Pig and Poultry Production

Antimicrobials are extensively used as growth promoters in animal feeds worldwide, but reliable estimates are lacking. We conducted an internet-based survey of commercial chicken and pig feed products officially approved for sale in Vietnam over the period March-June 2015. Information on the antimicrobial contents in feed products, alongside animal production data, was used to estimate in-feed antimicrobial consumption to produce one kilogram of live animal (chicken, pig), as well as to estimate country-wide antimicrobial consumption through animal feeds. A total of 1462 commercial feed formulations were examined. The survey-adjusted estimated antimicrobial contents were 25.7 and 62.3 mg/kg in chicken and pig feeds, respectively. Overall, it was estimated that 77.4 mg [95% CI 48.1-106.8] and 286.6 mg [95% CI 191.6-418.3] of in-feed antimicrobials were used to raise 1 kg of live chicken and pig, respectively. Bacitracin (15.5% feeds), chlortetracycline (11.4%), and enramycin (10.8%) were the most common antimicrobials present in chicken feed formulations, whereas bacitracin (24.8%), chlortetracycline (23.9%), and florfenicol (17.4%) were the most common in pig feed formulations. Overall, 57% of the total quantitative usage consisted of antimicrobials regarded by WHO of importance for human medicine, including amoxicillin, colistin, tetracyclines, neomycin, lincomycin, and bacitracin. These figures confirm a very high magnitude of in-feed consumption of antimicrobials, especially in pig production. Results from this study should encourage further monitoring of antimicrobials used in animal production, and foster discussion about existing policies on inclusion of antimicrobials in animal feed rations.

Label-Free Photonic Crystal-Based β-Lactamase Biosensor for β-Lactam Antibiotic and β-Lactamase Inhibitor

A simple, label-free, and visual photonic crystal-based β-lactamase biosensor was developed for β-lactam antibiotic and β-lactamase inhibitor in which the penicillinase (a β-lactamase) was immobilized on the pH-sensitive colloidal crystal hydrogel (CCH) film to form penicillinase colloidal crystal hydrogel (PCCH) biosensing film. The hydrolysis of penicillin G (a β-lactam antibiotic) can be catalyzed by penicillinase to produce penicilloic acid, leading to a pH decrease in the microenvironment of PCCH film, which causes the shrink of pH-sensitive CCH film and triggers a blue-shift of the diffraction wavelength. Upon the addition of β-lactamase inhibitor, the hydrolysis reaction is suppressed and no clear blue-shift is observed. The concentrations of β-lactam antibiotic and β-lactamase inhibitor can be sensitively evaluated by measuring the diffraction shifts. The minimum detectable concentrations for penicillin G and clavulanate potassium (a β-lactamase inhibitor) can reach 1 and 0.1 μM, respectively. Furthermore, the proposed method is highly reversible and selective, and it allows determination of penicillin G in fish pond water samples.

The effects of Natucin C-Natucin P mixture on blood biochemical parameters, antioxidant activity and non-specific immune responses in tilapia (Oreochromis niloticus)

Natucin C (NC) and Natucin P (NP) are two kinds of antimicrobial peptides (AMPs). In the present study, the effects of NC-NP mixture on a tilapia species (Oreochromis niloticus) were examined. Animals were fed with either a control diet or one of five AMP-supplemented diets for eight weeks. AMP-supplemented diets contained five increasing levels of NP from G1 to G5 and one level of NC (200 mg/kg). Results showed that fish in the G3, G4 and G5 groups had significantly higher levels of total protein (TP), albumin (ALB) and globulin (GLO) in serum than fish in the control group. Fish fed with G4 and G5 diets exhibited significantly higher high-density lipoprotein cholesterol (HDL-C) levels compared to the control fish. Lipopolysaccharide (LPS) levels in all AMP-supplemented groups were significantly lower than the control. In addition, the total antioxidant capacity (TAOC) and lysozyme (LZM) activities were significantly increased in fish fed with the G3 and G4 diets, respectively compared to the control. The serum malondialdehyde (MDA) levels in fish fed with AMP-supplemented diets were significantly decreased compared to those not supplemented with AMPs. Furthermore, the mRNA expressions of tumor necrosis factor alpha (TNF-α), interleukin-1-beta (IL-1β), gamma interferon (IFN-γ) and heat shock protein 70 (HSP70) in the hepatopancreas, spleen, kidney and gill were measured. Overall, the expression levels were enhanced in an NP dose-dependent and tissue-specific manner. The expressions of four genes in four organs (except IL-1β in spleen, and TNF-α and HSP70 in gill) were significantly upregulated in fish fed with the G5 diet. Fish fed with the G4 diet had increased expression levels of IL-1β in spleen and IFN-γ in kidney. The relative expression levels of TNF-α, IL-1β and HSP70 in the hepatopancreas in fish fed with the G3 diet were significantly upregulated compared to the control. Transcriptional levels of IL-1β and HSP70 in the hepatopancreas, IFN-γ and HSP70 in the kidney and IL-1β in the gills of fish fed with the G2 diet were upregulated. Taken together, our results indicated that the NC-NP mixture can enhance the antioxidant capacity and innate immune ability of O. niloticus, indicating that this mixture might be a potential alternative to antibiotics when used as a feed additive.

Effects of dietary supplementation with freshwater microalgae on growth performance, nutrient digestibility and gut health in weaned piglets

In pigs, digestive disorders associated with weaning lead to antibiotic use to maintain intestinal health. Microalgae have been studied in humans and rodents for their beneficial effects on health. The nutritional value of microalgae in animal diets has been assessed, but results were not conclusive. Dietary supplementation with microalgae as an alternative to antibiotic use was studied in two trials (72 piglets with initial BW=9.1±1.1 kg in trial 1 and 24 piglets with initial BW=9.1±0.9 kg in trial 2). All piglets were weaned at 28 days of age and then housed in individual cages. Piglets were randomly allocated to one of the four diets during 2 weeks after weaning: a standard diet with no supplementation (NC) or the standard diet supplemented with 1% Spirulina (SP), with 1% Chlorella (CV), or with 0.2% of colistin as positive control (PC). Trial 1 was performed to determine the effect of microalgae supplementation from 28 to 42 days on performance and incidence of diarrhoea. Animals received then a standard diet from 42 to 56 days of age. Trial 2 was performed from 28 to 42 days of age to assess nutrient digestibility of the experimental diets and to determine inflammatory status and intestinal morphology at 42 days of age. In trial 1, 94% of the pigs had diarrhoea in the 1st week after weaning with no beneficial effect of colistin on diarrhoea incidence, average daily feed intake (ADFI), average daily gain (ADG), and gain : feed (G : F) ratio. This suggests that the diarrhoea was due to digestive disorders that did not result from enterotoxigenic Escherichia coli infection. Supplementation with either Spirulina or Chlorella did not affect ADFI, ADG and G : F in trials 1 and 2 (P>0.10). Diarrhoea incidence was reduced in CV pigs compared with NC, SP and PC pigs (P<0.05). Total tract digestibility in pig receiving microalgae was greater for gross energy (P<0.05), and tended to be greater for dry matter, organic matter and NDF (P<0.10) compared with NC and PC pigs. Villus height at the jejunum was greater in SP and CV pigs compared with NC and PC pigs (P<0.05). This study shows a potential effect of both Spirulina and Chlorella supplementation on intestinal development and a potential of Chlorella supplementation to manage mild digestive disorders. Further investigation is necessary to determine the mechanism action of Spirulina and Chlorella on gut health and physiology.

Passive immunisation, an old idea revisited: Basic principles and application to modern animal production systems

Immunisation by administration of antibodies (immunoglobulins) has been known for more than one hundred years as a very efficient means of obtaining immediate, short-lived protection against infection and/or against the disease-causing effects of toxins from microbial pathogens and from other sources. Thus, due to its rapid action, passive immunisation is often used to treat disease caused by infection and/or toxin exposure. However immunoglobulins may also be administered prior to exposure to infection and/or toxin, although they will not provide long-lasting protection as is seen with active immunisation (vaccination) in which an immunological memory is established by controlled exposure of the host to the pathogen in question. With multi-factorial infectious diseases in production animals, especially those that have proven hard to control by vaccination, the potential of passive immunisation remains big. This review highlights a number of examples on the use of passive immunisation for the control of infectious disease in the modern production of a range of animals, including pigs, cattle, sheep, goat, poultry and fish. Special emphasis is given on the enablement of passive immunisation strategies in these production systems through low cost and ease of use as well as on the sources, composition and purity of immunoglobulin preparations used and their benefits as compared to current measures, including vaccination (also comprising maternal vaccination), antibiotics and feed additives such as spray-dried plasma. It is concluded that provided highly efficient, relatively low-price immunoglobulin products are available, passive immunisation has a clear role in the modern animal production sector as a means of controlling infectious diseases, importantly with a very low risk of causing development of bacterial resistance, thus constituting a real and widely applicable alternative to antibiotics.

Effects of probiotic supplement (Bacillus subtilis and Lactobacillus acidophilus) on feed efficiency, growth performance, and microbial population of weaning rabbits

OBJECTIVE

This study aimed to investigate the effects of single or/and double strains of probiotic supplement on feed efficiency, growth performance, and microbial population in distal gastrointestinal tract (GIT) of weaning rabbits.

METHODS

Sixty-four weaning (28 days old) New Zealand White rabbits were randomly distributed into four groups with treatments including: basal diet without probiotic supplement (control) or supplemented as follows: 1×10⁶ cfu/g B. subtilis (BS group), 1×10⁷ cfu/g L. acidophilus (LA group), or 0.5×10⁶ cfu/g B. subtilis plus 0.5×10⁷ cfu/g L. acidophilus (BL group). During the research, the male and female rabbits were fed separately. Body weight of the rabbits was recorded at 28, 42, and 70 d of age.

RESULTS

There was an increase (p<0.05) in body weight gain for the LA group at 42 d. Rabbits fed BL responsed with a greater growth (p<0.05) and better feed conversion ratio (p<0.05) than those fed with no probiotic. Digestibility coefficients of dry matter, organic matter, crude protein, neutral detergent fiber, and gross energy were higher (p<0.05) in LA and BL groups than those in the control group. Male rabbits had higher (p<0.05) Bacilli spp. and Coliformis spp. in the ileum than female rabbits. Rabbits supplemented with BS had greater (p<0.05) numbers of bacilli in all intestinal segments than those receiving no probiotic, whereas intestinal Lactobacilli populations were greater (p<0.001) in the LA and BL diets compared to control. Average intestinal coliform populations were lowest (p<0.05) in the rabbits supplemented with LA as compared to those fed the control and BS.

CONCLUSION

Supplementation of L. acidophilus alone or in combination with B. subtilis at a half of dose could enhance number of gut beneficial bacteria populations, nutrient digestibility, cecal fermentation, feed efficiency, and growth performance, but rabbits receiving only B. subtilis alone were not different from the controls without probiotic.

Bacterial Succession in the Broiler Gastrointestinal Tract

A feeding trial was performed with broilers receiving a diet of wheat-based feed (WBF), maize-based feed (MBF), or maize-based concentrates supplemented with 15% or 30% crimped kernel maize silage (CKMS-15 or CKMS-30, respectively). The aim of the study was to investigate the bacterial community compositions of the crop, gizzard, ileum, and cecum contents in relation to the feeding strategy and age (8, 15, 22, 25, 29, or 36 days). Among the four dietary treatments, bacterial diversity was analyzed for MBF and CKMS-30 by 454 pyrosequencing of the 16S rRNA gene. Since the diets had no significant influence on bacterial diversity, data were pooled for downstream analysis. With increasing age, a clear succession of bacterial communities and increased bacterial diversity were observed.Lactobacillaceae(belonging mainly to the genus Lactobacillus) represented most of the Firmicutesat all ages and in all segments of the gut except the cecum. The development of a "mature" microbiota in broilers occurred during the period from days 15 to 22. Striking increases in the relative abundances of Lactobacillus salivarius(17 to 36%) and clostridia (11 to 18%), and a concomitant decrease in the relative abundance of Lactobacillus reuteri, were found in the ileum after day 15. The concentration of deconjugated bile salts increased in association with the increased populations of L. salivarius and clostridia. Both L. salivarius and clostridia deconjugate bile acids, and increases in the abundances of these bacteria might be associated with growth reduction and gastrointestinal (GI) disorders occurring in the critical period of broiler life between days 20 and 30.

What are the differences between aerobic and anaerobic toxic effects of sulfonamides on Escherichia coli?

Bacteria in the environment face the threat of antibiotics. However, most studies investigating the toxicity and toxicity mechanisms of antibiotics have been conducted on microorganisms in aerobic conditions, while studies examining the anaerobic toxicity and toxicity mechanisms of antibiotics are still limited. In this study, we determined the aerobic and anaerobic toxicities of sulfonamides (SAs) on Escherichia coli. Next, a comparison of the aerobic and anaerobic toxicities indicated that the SAs could be divided into three groups: Group I: log(1/EC50-anaerobic)>log(1/EC50-aerobic) (EC50-anaerobic/EC50-aerobic, the median effective concentration under anaerobic/aerobic conditions), Group II: log(1/EC50-anaerobic)≈log(1/EC50-aerobic), and Group III: log(1/EC50-anaerobic)<log(1/EC50-aerobic). Furthermore, this division was not based on the reactive oxygen species (ROS) level or the interaction energy (Ebinding) value, which represents the affinity between SAs and dihydropteroate synthase (dhps) but rather on the total binding energy. Furthermore, SAs with greatly similar structures were categorized into different groups. This deep insight into the difference between aerobic and anaerobic toxicities will benefit environmental science, and the results of this study will serve as a reference for the risk assessment of chemicals in the environment.

Dietary chitosan oligosaccharide supplementation improves foetal survival and reproductive performance in multiparous sows

Chitosan oligosaccharide (COS), a partially hydrolysed product of chitosan, has various important biological activities.

Determination of oxytetracycline residues in cattle meat marketed in the Kilosa district, Tanzania

Oxytetracycline is used to treat various diseases in cattle. However, its use may be associated with unacceptable residue levels in food. Oxytetracycline residues in tissues from indigenous cattle were determined in a cross-sectional study conducted in the Kilosa district, Tanzania, between November 2012 and April 2013. A total of 60 tissue samples, including muscle, liver and kidney, were collected from slaughterhouses and butchers and analysed for oxytetracycline using high-performance liquid chromatography. Oxytetracycline residues were found in 71.1% of the samples, of which 68.3% were above acceptable regulatory levels. The mean concentration of oxytetracycline across tissues was 3401.1 μg/kg ± 879.3 μg/kg; concentrations in muscle, liver and kidney were 2604.1 μg/kg ± 703.7 μg/kg, 3434.4 μg/kg ± 606.4 μg/kg and 3533.1 μg/kg ± 803.6 μg/kg, respectively. High levels of oxytetracycline residue in meat from indigenous cattle may pose a health threat to consumers in Kilosa. The findings possibly reflect a general lack of implementation of recommended withdrawal periods, ignorance about drug use and lack of extension services. Strict regulation of the use of antimicrobial drugs in the livestock industry and associated testing of animal-derived food sources prior to marketing are required.

Design of a sensitive fluorescent polarization immunoassay for rapid screening of milk for cephalexin

In this paper we describe the development of a sensitive, fast, and easily performed fluorescence polarization immunoassay for determination of cephalexin in milk. The experimental work was performed to increase sensitivity and specificity. Therefore, the structures of the tracers were varied by synthesis of both cephalexin (CEX) and cephalotin (CET) conjugates with a variety of fluorescent labels. Two rabbit antisera containing antibodies against cephalexin and cephalotin were tested in homologous and heterologous combinations with the tracers. For every working antibody-tracer combination, the analytical conditions and cross-reactivity for structural analogues-cephalosporins and other antibiotics that could also be present in milk-were determined. It was found that the highest sensitivity was achieved by use of the homologous pair CET-EDF-anti-CET antibody (limit of detection (LOD) 0.4 μg kg(-1) for standard solutions prepared in buffer), but this combination was not appropriate because of high cross-reactivity with CET. For subsequent experiments, therefore, CEX- EDF-anti-CEX antibody were chosen (LOD 0.8 μg kg(-1) for standard solutions prepared in buffer). Part of this manuscript is devoted to the variation of precipitation agents for pretreatment of milk before analysis; milk is an extremely complicated matrix. The optimum protein precipitation agent was methanol. This technique for cephalexin determination was characterized by a limit of detection of 1 μg kg(-1). The method was validated by using naturally contaminated and spiked milk samples. The results obtained corresponded very well with those obtained by HPLC, which was used as confirmation method.

The Value of the One Health Approach: Shifting from Emergency Response to Prevention of Zoonotic Disease Threats at Their Source

The majority of emerging infectious diseases have their source in animals, and emergence occurs at the human-animal interface, when infections in animals breach the species barrier to infect humans, the population in which they are often first identified. The response is often a series of emergency activities to contain and manage the infection in human populations, and at the same time to identify the source of the infection in nature. If an infection is found to have a source in animals, and if animals cause a continuous threat of human infection, culling is often recommended, with severe economic impact. Currently the animal and human medicine sectors are working toward interacting more closely at the animal-human interface through joint surveillance and risk assessment, and research is under way in geographic areas where emergence at the animal-human interface has occurred in the past. The goal of this research is to identify infectious organisms in tropical and other wild animals, to genetically sequence these organisms, and to attempt to predict which organisms have the potential to emerge in human populations. It may be more cost-effective, however, to learn from past emergence events and to shift the paradigm from disease surveillance, detection, and response in humans to prevention of emergence at the source by understanding and mitigating the factors, or determinants, that influence animal infection. These determinants are clearly understood from the study of previous emergence events and include human-induced changes in natural environments, urban areas, and agricultural systems; raising and processing of animal-based foods; and the roles of global trade, migration, and climate change. Better understanding of these factors gained from epidemiological investigation of past and present emergence events, and modeling and study of the cost-effectiveness of interventions that could result in their mitigation, could provide evidence necessary to better address the political and economic barriers to prevention of infections in animals. Such economically convincing arguments for change and mitigation are required because of the basic difference in animal health, driven by the need for profit, and human health, driven by the need to save lives.

Clays as dietary supplements for swine: A review

Clays are crystalline, hydrated aluminosilicate molecules composed of alkali and alkaline earth cations along with small amounts of various other elements. The best-known are montmorillonite, smectite, illite, kaolinite, biotite and clinoptilolite. The molecules in these clays are arranged in three-dimensional structures creating internal voids and channels capable of trapping a wide variety of molecules. As a result of this structure, clay minerals are regarded as a simple and effective tool for the prevention of the negative effects of many toxic compounds. Dietary supplementation with clays has been shown to improve weight gain and feed conversion in pigs. Where improvements in performance have been noted, one of the most likely explanations for the improvement is the fact clays increase nutrient digestibility. Clays reduce the speed of passage of feed along the digestive tract which allows more time for digestion. Feeding clays also causes morphological changes in the intestinal mucosa such as an increase in villus height and an increase in the villus height to crypt depth ratio. These changes increase the surface area of the gastrointestinal tract thus increasing nutrient digestibility. Several studies have indicated that feeding clay reduces the incidence, severity and duration of diarrhea in pigs. The mechanism for the reduction in diarrhea is likely due to increases in the numbers of Bifidobacteria and Lactobacillus and decreases in Clostridia and E. coli in the small intestine of pigs fed clays. In addition, the numbers of pigs born alive and weaned, birth weight and weaning weight have been shown to be higher for sows fed clays. Several studies have indicated that clays can help mitigate the effects of mycotoxins. The aim of the present review is to focus on the various clays which have been given attention in recent research and to discuss their potential to improve pig performance.

Changes in diversity of cultured bacteria resistant to erythromycin and tetracycline in swine manure during simulated composting and lagoon storage

This study investigated the impact of composting and lagoon storage on survival and change in diversity of tetracycline-resistant (Tc(r) ) and erythromycin-resistant (Em(r) ) bacteria and the resistance genes they carry in swine manure. Treatments were arranged as a 2 × 2 factorial design: composting vs lagoon storage and 0 vs 1% Surround WP Crop Protectant (a clay product) in three replicates. After 48 days of treatments, resistant bacteria were enumerated by selective plating and identified by 16S rRNA gene sequencing. The erm and the tet gene(s) carried by the resistant isolates were screened using class-specific PCR assays. The plate counts of Tc(r) and Em(r) bacteria decreased by 4-7 logs by composting, but only by 1-2 logs by the lagoon treatment. During the treatments, Acinetobacter gave way to Pseudomonas and Providencia as the largest resistant genera. The clay product had little effect on survival or diversity of resistant bacteria. Of six classes of erm and seven classes of tet genes tested, changes in prevalence were also noted. The results indicate that composting can dramatically shift Tc(r) and Em(r) bacterial populations, and composting can be an effective and practical approach to decrease dissemination of antibiotic resistance from swine farms to the environment.

SIGNIFICANCE AND IMPACT OF THE STUDY

The presented research provided evidence that composting is much more effective than lagoon storage in dramatically decreasing culturable bacteria resistant to erythromycin and tetracycline in swine manure. Considerable diversity changes of resistant bacteria were also demonstrated during composting or lagoon storage. Overall, Acinetobacter was the major resistant genus in untreated swine manure, but pseudomonads and Providencia became the major resistant genera after the treatments. This is the first study that investigated diversity changes of cultured bacteria resistant to these two antibiotics during composting and lagoon storage of swine manure. New genes encoding resistance to the two antibiotics were also implied in the cultured isolates.

Feed Fermentation with Reuteran- and Levan-Producing Lactobacillus reuteri Reduces Colonization of Weanling Pigs by Enterotoxigenic Escherichia coli

This study determined the effect of feed fermentation with Lactobacillus reuteri on growth performance and the abundance of enterotoxigenic Escherichia coli (ETEC) in weanling piglets. L. reuteri strains produce reuteran or levan, exopolysaccharides that inhibit ETEC adhesion to the mucosa, and feed fermentation was conducted under conditions supporting exopolysaccharide formation and under conditions not supporting exopolysaccharide formation. Diets were chosen to assess the impact of organic acids and the impact of viable L. reuteri bacteria. Fecal samples were taken throughout 3 weeks of feeding; at the end of the 21-day feeding period, animals were euthanized to sample the gut digesta. The feed intake was reduced in pigs fed diets containing exopolysaccharides; however, feed efficiencies did not differ among the diets. Quantification of L. reuteri by quantitative PCR (qPCR) detected the two strains used for feed fermentation throughout the intestinal tract. Quantification of E. coli and ETEC virulence factors by qPCR demonstrated that fermented diets containing reuteran significantly (P < 0.05) reduced the copy numbers of genes for E. coli and the heat-stable enterotoxin in feces compared to those achieved with the control diet. Any fermented feed significantly (P < 0.05) reduced the abundance of E. coli and the heat-stable enterotoxin in colonic digesta at 21 days; reuteran-containing diets reduced the copy numbers of the genes for E. coli and the heat-stable enterotoxin below the detection limit in samples from the ileum, the cecum, and the colon. In conclusion, feed fermentation with L. reuteri reduced the level of colonization of weaning piglets with ETEC, and feed fermentation supplied concentrations of reuteran that may specifically contribute to the effect on ETEC.

Phytogenic compounds as alternatives to in-feed antibiotics: potentials and challenges in application

This article summarizes current experimental knowledge on the efficacy, possible mechanisms and feasibility in the application of phytogenic products as feed additives for food-producing animals. Phytogenic compounds comprise a wide range of plant-derived natural bioactive compounds and essential oils are a major group. Numerous studies have demonstrated that phytogenic compounds have a variety of functions, including antimicrobial/antiviral, antioxidative and anti-inflammation effects and improvement in the palatability of feed and gut development/health. However, the mechanisms underlying their functions are still largely unclear. In the past, there has been a lack of consistency in the results from both laboratory and field studies, largely due to the varied composition of products, dosages, purities and growing conditions of animals used. The minimal inhibitory concentration (MIC) of phytogenic compounds required for controlling enteric pathogens may not guarantee the best feed intake, balanced immunity of animals and cost-effectiveness in animal production. The lipophilic nature of photogenic compounds also presents a challenge in effective delivery to the animal gut and this can partially be resolved by microencapsulation and combination with other compounds (synergistic effect). Interestingly, the effects of photogenic compounds on anti-inflammation, gut chemosensing and possible disruption of bacterial quorum sensing could explain a certain number of studies with different animal species for the better production performance of animals that have received phytogenic feed additives. It is obvious that phytogenic compounds have good potential as an alternative to antibiotics in feed for food animal production and the combination of different phytogenic compounds appears to be an approach to improve the efficacy and safety of phytogenic compounds in the application. It is our expectation that the recent development of high-throughput and "omics" technologies can significantly advance the studies on the mechanisms underlying phytogenic compounds' functions and, therefore, guide the effective use of the compounds.

Study on inclusion of probiotic, prebiotic and its combination in broiler diet and their effect on carcass characteristics and economics of commercial broilers

Background and Aim:

In today era, broiler industry facing a problem of price hiking of feed of broiler, also in competitive era there should be lower feed cost, lower feed conversion ratio, low feed consumption yet good body weight at marketable age.

Materials and Methods:

Day-old commercial broiler chicks (n=200) were distributed randomly into 5 dietary treatment groups viz. control (T₁), probiotic in the feed @ 100 g/tonne of feed (T₂), prebiotic in the feed @ 500 g/tonne of feed (T₃), probiotic + prebiotic @ 100 g/tonne and 500 g/tonne of feed, respectively (T₄) and probiotic + prebiotic @ 50 g/tonne and 250 g/tonne of feed (T₅). The growth of broilers and dressing weight along with the weight of giblet (liver without gall bladder, gizzard without serous layer, and heart without pericardium), Kidney, Abdominal fat, Length of Intestine and dressing percentage were measured. Economics in terms of Return Over Feed Cost (ROFC) and European Performance Efficiency Index (EPEI) was calculated.

Results:

Among all carcass traits, dressing percentage, abdominal fat weight and abdominal fat percentage (as a percentage of dressed weight) were recorded significant (p<0.05) difference among different treatment groups. The income from selling of the birds was significantly (p<0.05) higher in all treatment groups than the control group but there was a non-significant difference between supplemented groups. Feed cost during whole experimental period was significantly (p<0.05) lower in synbiotic supplemented groups (T₄ and T₅) than other groups. ROFC of all treatment group found significantly (p<0.05) higher than the control group.

Conclusion:

It can be concluded that the diet supplemented with synbiotic (100% level) was most efficient in terms of EPEI and synbiotic (50% level) in terms of ROFC. Hence, as feed supplement, synbiotic has a beneficial effect over probiotic and prebiotic when used alone.

Effects of chito-oligosaccharides and L-carnitine supplementation in diets for Japanese quails on performance, carcass traits and some blood parameters

The aim of this study was to determine effects of dietary supplementation with chitosanoligosaccharides (COS) and L-carnitine, individually or dually, on growth performance, carcass traits and some blood serum parameters in quails. A total of 192, four days old, Japanese quail chicks were allotted four groups, each of which included four replicates (12 birds per replicate). The groups received the same basal diet supplemented with 0 (Control), 150mg/kg chitosanoligosaccharides (COS), 150mg/kg L-carnitine (Carnitine), and 150 mg/kg chitosanoligosaccharides+150 mg/kg L-carnitine (COS+Car.) during the starter (1 to 21 days) and a grower (22 to 42 days) period. The feeding trial shoved that COS, L-carnitine and COS+L-carnitine had no significant effect on live weight, live weight gain, feed consumption and feed conversion. Supplementation with COS+L-carnitine induced higher leg ratio from than that of the Control. There were no differences on serum albumin, total protein, glucose and total cholesterol concentrations. It is concluded that due to the obtained higher leg ratio from COS+Car. group, after analysis of the profit and loss, if is economically profitable, chitosanoligosaccharides+L-carnitine could be added quail diets.

Microbes versus microbes: control of pathogens in the food chain

Foodborne illness continues as a considerable threat to public health. Despite improved hygiene management systems and increased regulation, pathogenic bacteria still contaminate food, causing sporadic cases of illness and disease outbreaks worldwide. For many centuries, microbial antagonism has been used in food processing to improve food safety. An understanding of the mode of action of this microbial antagonism has been gained in recent years and potential applications in food and feed safety are now being explored. This review focuses on the potential opportunities presented, and the limitations, of using microbial antagonism as a biocontrol mechanism to reduce contamination along the food chain; including animal feed as its first link. © 2014 Society of Chemical Industry.

Reduction of veterinary antimicrobial use in the Netherlands. The Dutch success model

Use of antimicrobials in animals poses a potential risk for public health as it contributes to the selection and spread of antimicrobial resistance. Although knowledge of the negative consequences of extensive antimicrobial use in humans and animals accumulated over the decades, total therapeutic antimicrobial use in farm animals in the Netherlands doubled between 1990 and 2007. A series of facts and events formed a window of opportunity to reduce antimicrobial use in farm animals. The recent discovery of significant reservoirs of antimicrobial-resistant pathogens such as methicillin-resistant Staphylococcus aureus (MRSA) and extended spectrum beta-lactamase-producing bacteria (ESBL) in farm animals, with potential public health implications, combined with an increasing lack of confidence of the public in intensive livestock industries, and discrepancy between the very low antimicrobial use in humans and high use in animals, resulted in intensive collaboration between the government, veterinary professional organizations and important stakeholders within the livestock sector. A combination of compulsory and voluntary actions with clear reduction goals resulted in a 56% reduction in antimicrobial use in farm animals in the Netherlands between 2007 and 2012 and aims at accomplishing a 70% reduction target in 2015. This article describes and analyses the processes and actions behind this transition from an abundant antimicrobial use in farm animals towards a more prudent application of antimicrobials in farm animals in the Netherlands.

The importance of growth kinetic analysis in determining bacterial susceptibility against antibiotics and silver nanoparticles

Routine antibiotics susceptibility testing still relies on standardized cultivation-based analyses, including measurement of inhibition zones in conventional agar diffusion tests and endpoint turbidity-based measurements. Here, we demonstrate that common off-line monitoring and endpoint determination after 18-24 h could be insufficient for reliable growth-dependent evaluation of antibiotic susceptibility. Different minimal inhibitory concentrations were obtained in 20- and 48 h microdilution plate tests using an Enterococcus faecium clinical isolate (strain UKI-MB07) as a model organism. Hence, we used an on-line kinetic assay for simultaneous cultivation and time-resolved growth analysis in a 96-well format instead of off-line susceptibility testing. Growth of the Enterococcus test organism was delayed up to 30 h in the presence of 0.25 μg mL(-1) of vancomycin and 8 μg mL(-1) of fosfomycin, after which pronounced growth was observed. Despite the delayed onset of growth, treatment with fosfomycin, daptomycin, fusidic acid, cefoxitin, or gentamicin resulted in higher maximum growth rates and/or higher final optical density values compared with antibiotic-free controls, indicating that growth stimulation and hormetic effects may occur with extended exposure to sublethal antibiotic concentrations. Whereas neither maximum growth rate nor final cell density correlated with antibiotic concentration, the lag phase duration for some antibiotics was a more meaningful indicator of dose-dependent growth inhibition. Our results also reveal that non-temporal growth profiles are only of limited value for cultivation-based antimicrobial silver nanoparticle susceptibility testing. The exposure to Ag(0) nanoparticles led to plasma membrane damage in a concentration-dependent manner and induced oxidative stress in Enterococcus faecium UKI-MB07, as shown by intracellular ROS accumulation.

Generation of bi-transgenic pigs overexpressing human lactoferrin and lysozyme in milk

Intensive swine production industry uses antibiotics to treat diseases and improve pig growth. This can not only cause antibiotic resistance, but can also pollute the environment or eventually affect human public health. To date, human lactoferrin (hLF) and human lysozyme (hLZ) have been known as non-adaptive but interactive antimicrobial members and could act in concert against bacteria, which contribute to host defense. Therefore, their expression in pigs might be an alternative strategy for replacing antibiotics in the pig production industry. In our study, we produced hLF and hLZ bi-transgenic pigs and assessed the milk's antibacterial ability. Integration of both transgenes was confirmed by PCR and southern blot. Both the hLF and hLZ were expressed in the mammary gland of bi-transgenic pigs, as detected by western blotting. The expression amounts were 6.5 g/L for hLF and 1.1 mg/L for hLZ using ELISA. Interestingly, pig milk containing hLF and hLZ had synergistic antimicrobial activity. Our results suggest an alternative approach for avoiding the use of antibiotics in the pig industry, which would be of great benefit to the commercial swine production.

Antibiotic resistance of Vibrio harveyi isolated from seawater in Korea

Vibrio harveyi is an opportunistic human pathogen that may cause gastroenteritis, severe necrotizing soft-tissue infections, and primary septicemia, with a potentially high rate of lethality. In this study, we isolated and characterized V. harveyi from seawater collected from the West Sea in Korea, including sites located near shellfish farms. For the initial isolation of putative V. harveyi, isolates were incubated on thiosulfate citrate bile salt sucrose agar plates for 24h, followed by selection of greenish colonies. Gram-negative and oxidase-positive colonies were subsequently confirmed by biochemical assays and the API 20E kit test system. Species-specific 16S rRNA and hemolysin genes were used to design V. harveyi-specific PCR primers. From 840 seawater samples, a total of 2 strains of V. harveyi were isolated from shellfish farm seawater. The two isolates were subjected to profiling against 16 antibiotics and found to be resistant to cephalothin, vancomycin, ampicillin, cefepime, cefotetan, and streptomycin.

Forsythia suspensa Extract Has the Potential to Substitute Antibiotic in Broiler Chicken

Two experiments were conducted to investigate the potential for Forsythia suspensa extract (FSE) to substitute for antibiotic in broiler chicken. First, a well-diffusion assay procedure and a 2-fold dilution method were used to determine the bacteriostatic activity of FSE on Escherichia coli K88, staphylococcus aureus, and salmonella was assayed. An inhibitory effect of FSE was observed on the growth of these bacteria. This effect seems to be dose depended, which disappeared after 25.00, 12.50, 1.56 mg/ml. Second, a 42-d trial with 252 broiler chickens (d 1, 38.7±1.1 g BW) was conducted to evaluate the effect of dietary supplementation of FSE in broiler chicken. The feeding program consisted of a starter diet from d 1 to 21 and a finisher diet from d 22 to 42. Dietary treatments included were: i) NC: negative control fed a corn-soybean meal based diet; ii) PC: positive control group fed based diet with chlortetracycline; and iii) FC: a test group fed with 100 mg FSE/kg diet. In this study growth performance did not differ among treatments during the starter period. However, dietary supplemental chlortetracycline and FSE increased (p<0.05) average daily gain (ADG), average daily feed intake (ADFI) compared with NC during the finisher and overall phase. Apparent digestibility of calcium on d 21, digestibility of energy and calcium on d 42 of FC was greater (p<0.05) than NC. Moreover, cecal Escherichia coli counts for birds from FC were lower (p<0.05) than NC. Dietary FSE supplementation also improved (p<0.05) villus height and villus height to crypt depth ratios in both duodenum and ileum and decreased (p<0.05) crypt depth in the duodenum. Duodenum villus height and villus height to crypt depth ratio in both duodenum and ileum from the FC group were also greater (p<0.05). Serum growth hormone and IGF-1 were not influenced by different treatments. Apparently, FSE has the potential to substitute for antibiotic in broiler chicken.