Antibiotics Details with their Withdrawal Time Period

Salt	Description	Mode of Action	Withdrawal Time
Avilamycin	Avilamycin is an orthosomycin antibiotic complex produced by the fermentation of Streptomyces viridochromogenes. Avilamycin is primarily active against gram-positive bacteria.	Avilamycin inhibits protein synthesis. It is thought to bind to 50S ribosomal subunit. It prevents the association of IF2 which inhibits the formation of the mature 70S initiation complex and the correct positioning of the tRNA in the aminoacyl site.	NIL
Bacitracin (ZB, BMD)	Bacitracin is a mixture of related cyclic peptides produced by organisms of the licheniformis group of Bacillus subtilis var Tracy, These peptides disrupt Gram-positive bacteria by interfering with cell wall and peptidoglycan synthesis.	Bacitracin interferes with the dephosphorylation of C55-isoprenyl pyrophosphate, also known as bactoprenol, a membrane carrier molecule that transports the building-blocks of the peptidoglycan bacterial cell wall outside of the inner membrane	It does not absorb in the intestine. So, it has no WHP
Chlortetracycline	Chlortetracycline belong to one of the important classes of broad-spectrum antibiotics. Two of the more common semisynthetic tetracyclines that have been marketed for decades are doxycycline and minocycline. The tetracyclines inhibit bacterial growth by inhibiting bacterial protein synthesis by preventing the association of aminoacyl-tRNA with bacterial ribosomes	Chlortetracycline, like other tetracyclines, competes for the A site of the bacterial ribosome. This binding competes with tRNA carrying amino acids preventing the addition of more amino acids to the peptide chain. This inhibition of protein synthesis ultimately inhibits growth and reproduction of the bacterial cell as necessary proteins cannot be synthesized.	It has withdrawal time of 1-5 days
Colistin Sulphate	Colistin, also known as polymyxin E, is an antibiotic produced by certain strains of the bacteria Paenibacillus polymyxa. Colistin is a mixture of the cyclic polypeptides colistin A and B and belongs to the class of polypeptide antibiotics known as polymyxins. Colistin is effective against most Gram-negative bacilli.	Colistin is a polycationic peptide and has both hydrophilic and lipophilic moieties. These cationic regions interact with the bacterial outer membrane, by displacing magnesium and calcium bacterial counter ions in the lipopolysaccharide. Hydrophobic/hydrophilic regions interact with the cytoplasmic membrane just like a detergent, solubilizing the membrane in an aqueous environment. This effect is bactericidal even in an isosmolar environment.	7 Days
Enramycin	Enramycin or Enduracidin is a polypeptide antibiotic produced by Streptomyces fungicidus. Enramycin is widely used as a feed additive for pigs and chickens to prevent necrotic enteritis induced by Gram-positive gut pathogens. It improves weight gain and feed conversion	Enramycin acts as an inhibitor of the enzyme, MurG, which is essential for cell wall biosynthesis in Gram-positive bacteria. MurG catalyzes the transglycosylation reaction in the last step of peptidoglycan biosynthesis. Inhibiting this step greatly compromises cell wall integrity leading to cell lysis.	7 days
Flavomycin	Bambermycin (flavomycin) is a complex of antibiotics obtained from Streptomyces bambergiensis and Streptomyces ghanaensis used as a food additive for poultry. Bambermycin is predominately effective against Gram-positivepathogenic bacteria	Flavomycin inhibits the transglycosylation step of peptidoglycan biosynthesis, a structural component of the bacterial cell wall. This causes accumulation of cell wall intermediates, and leads to lysis and cell death.	Nil
Lincomycin	Lincomycin is a lincosamide antibiotic that comes from the actinomycete Streptomyces lincolnensis. Lincomycin is a narrow spectrum antibiotic with activity against Gram-positive and cell wall-less bacteria including pathogenic species of Streptococcus, Staphylococcus, and Mycoplasma	Lincomycin inhibits protein synthesis in susceptible bacteria by binding to the 50 S subunits of bacterial ribosomes and preventing peptide bond formation upon transcription.	Nil
Neomycin	A component of neomycin that is produced by Streptomyces fradiae. On hydrolysis it yields neamine and neobiosamine B.	Neomycin is a bactericidal aminoglycoside antibiotic that binds to the 30S ribosome of susceptible organisms. Binding interferes with mRNA binding and acceptor tRNA sites and results in the production of non-functional or toxic peptides.	Nil
Nosiheptide	Nosiheptide is a sulfur-containing cyclic polypeptide, is highly active against Gram-positive bacteria and few Gram-negative bacteria, especially Clostridium Perfringens, Staphylococcus Aureus. Nosiheptide acts bacteriostatically in low dose and bactericidally in high dose.	Nosiheptide inhibits bacterial protein synthesis by inhibiting function of elongation factors Tu and G and greatly reduce the synthesis of guanosine penta- and tetraphosphates in response to stringent factor.	7 Days
Tylosin	Tylosin is an antibiotic and a bacteriostatic feed additive used in veterinary medicine. It has a broad spectrum of activity against Gram-positive organisms and a limited range of Gram-negative organisms.	Tylosin has a bacteriostatic effect on susceptible organisms, caused by inhibition of protein synthesis through binding to the 50S subunit of the bacterial ribosome.	5 Days
Tiamulin Hydrogen Fumarate	Tiamulln is a semi-synthetic derivative of pleuromutilin. It is the only member of the pleuromutili ln class of the diterpenic antibiotics which is approved for use at mts time. It is typically available for oral use as the Tiamulin base or the hydrogen fumarate salt. In some references Tiamulln is considered with the macrolide group of antibiotics.	Tiamulin affects bacterial protein synthesis. It has a strong affinity for the 50S ribosomal sub-unit resulting in breakdown in the peptide chain immediately following initiation.	3 Days
Virginiamycin	Virginiamycin is a streptogramin antibiotic similar to pristinamycin and quinupristin/dalfopristin. It is a combination of pristinamycin IIA(Virginiamycin M1) and Virginiamycin S1.	virginiamycin M blocks the elongation of polypeptide chains by inhibiting both the binding of aminoacyl-tRNA to ribosomes directed by elongation factor Tu (EF-Tu) and the peptidyl transferase reaction.	Nil

Manage somatic cell count and aflatoxins for milk quality

Author: Elliot Block, Ph.D., Research Fellow and Director of Research Arm & Hammer Animal and Food Production

by: CAST PHARMA

Regardless of your milk volume goals, producing high quality milk is your ultimate mission as a dairy producer. Somatic cell count (SCC) and protein content affect dairy product flavour, shelf life and cheese yield. And it’s mandatory to keep contaminants such as aflatoxins out of milk to meet regulatory standards, market expectations and consumer trust.

Many factors affect milk quality, including weather, hygiene, animal genetics and product handling. Diet often plays a critical role as well. Deficiencies in energy or essential nutrients can hamper cows’ resistance to mastitis pathogens. Maintaining the cow’s immune system can help her ward off bacterial challenges that cause high SCC.

RFCs support the immune system

One management solution to consider for bolstering immunity is feeding Celmanax to your lactating cows. The Refined Functional Carbohydrates (RFCs) in Celmanax support the immune system to help cows become more resilient against environmental challenges, including bacteria that impact milk quality. RFCs also optimise digestion and mitigate aflatoxins that can carry over in milk when cows eat contaminated feedstuffs.

Somatic cell count reduction

Research shows how improved immunity translates into higher milk quality. In three separate studies (Study 1, Study 2, Study 3), cows fed RFCs had numerically lower SCCs compared with control groups without the feed additive (Figure 1).

Figure 1 – Celmanax effect on SCC (x 1,000 CELLS/ML).

Preventing aflatoxins in milk

Another milk quality concern is potential carryover of aflatoxin in milk, caused by Aspergillus flavus fungus and related species of moulds in feed. Although many types of mycotoxins occur commonly in feed, a specific concern for dairy feed is aflatoxin B1, which converts to the metabolite aflatoxin M1 during digestion. Aflatoxin M1 can then transfer to the cow’s milk. At high levels, aflatoxin M1 is toxic to humans and animals.

It’s important to know that thresholds limits for aflatoxin M1 in milk vary from country to country. For example, in Europe the maximum aflatoxin M1 content allowed in milk is 50 parts per trillion (ppt), while the US maximum is 500 ppt. Milk with levels exceeding this amount must be discarded. If your lactating cows eat feed containing aflatoxins at 20 parts per billion (ppb) or greater, realise that their milk may exceed the tolerance levels for aflatoxins in milk1.

Mycotoxin contamination

Regardless of the tolerance levels in your region, it’s important to consider the risk of aflatoxin contamination. The levels of feed contamination vary from year to year based on growing conditions, but mycotoxins are almost always present. A 10-year study2 of mycotoxins in feed, involving 72,821 samples from 100 countries, found that mycotoxin contamination is the rule rather than the exception.

In research at 2 dairy production sites affected by alflatoxins, feeding RFCs helped mitigate aflatoxins carried over in milk. Cows in the study consumed feed contaminated with about 10 ppb of alfatoxin B1. As a result, a significant number of them secreted aflatoxin M1 in their milk – more than 40% of the herd at one of the sites.

Figure 2 – Celmanax mitigation of aflatoxin M1 in milk.

The study showed that supplementing rations with RFCs effectively blocked the transfer of aflatoxin M13 to the milk of cows fed the contaminated feed. Within 3 to 7 days of starting on the feed additive, the cows in the study no longer secreted aflatoxin M1 into milk (Figure 2).

RFCs work in synergy to help cows overcome multiple environmental stressors to maintain health and productivity – as well as milk quality.

5 principles to consider when designing biosecurity programmes

Biosecurity is the foundation for all disease prevention programs and all the more important in antibiotic reduction scenarios. It includes the combination of all measures taken to reduce the risk of introduction and spread of diseases and is based on the prevention of and protection against infectious agents. Its fundament is the knowledge of disease transmission processes.

 

Although biosecurity is considered the cheapest and most effective intervention in antibiotic reduction programmes, compliance is often low and difficult. 

The application of consistently high standards of biosecurity can substantially contribute to the reduction of antimicrobial resistance, not only by preventing the introduction of resistance genes into the farm but also by lowering the need to use antimicrobials.

LOWER USE OF ANTIMICROBIALS WITH HIGHER BIOSECURITY

Studies and assessments such as those done by (Laanen, et al., 2013), (Gelaude, et al., 2014), (Postma, et al., 2016), (Collineau, et al., 2017) and (Collineau, et al., 2017a) relate a high farm biosecurity or improvements in biosecurity with lower antimicrobial use. Laanen, Postma, and Collineau studied the profile of swine farmers in different European countries, finding a relation between a high level of internal biosecurity, efficient control of infectious diseases, and a reduced need for antimicrobials.

Others such as Gelaude and Collineau studied the effect of interventions. The former examined Belgian broiler farms, finding a reduction of antimicrobial use by almost 30% when biosecurity and other farm issues were improved within a year. The latter studied swine farms located in Belgium, France, Germany and Sweden, in which antimicrobial use was also reduced in 47% across all farms and observed that farms with the higher biosecurity compliance and who also took a holistic approach, making other changes (e.g. management and nutrition), achieved a higher reduction in antimicrobial use.

BIOSECURITY INTERVENTIONS PAY OFF

Of course, the interventions necessary to achieve an increased level of biosecurity carry some costs. However, the interventions, especially if taken with other measures such as improved management of new-born animals and nutritional improvements, also improve productivity. The same studies which report that biosecurity improvements decrease antimicrobial use also report an improvement in animal performance. In the case of broilers, Laanen (2013) found a reduction of 0.5 percentual points in mortality and one point in FCR; and Collineau (2017) obtained an improvement during both the pre-weaning and the fattening period of 0.7 and 0.9 percentual points, respectively.

IMPLEMENTATION, APPLICATION AND EXECUTION

Although biosecurity is considered the cheapest and most effective intervention in antibiotic reduction programmes, compliance is often low and difficult. The implementation, application, and execution of any biosecurity programme involve adopting a set of attitudes and behaviours to reduce the risk of entrance and spread of disease in all activities involving animal production or animal care. Measures should not be constraints but part of a process aimed at improving the health of animals and people, and a piece of the holistic approach to reduce antibiotics and improve performance.

DESIGNING EFFECTIVE BIOSECURITY PROGRAMMES: CONSIDER THESE 5 PRINCIPLES

When designing or evaluating biosecurity programmes, we can identify 5 principles that need to be applied. These principles set the ground for considering and evaluating biosecurity interventions:

1. Separation: Know your enemy, but don’t keep it close

It is vital to have a good separation between high and low-risk animals or areas on the farm, as well as dirty (general traffic) and clean (internal movements) areas on the farm. This avoids not only the entrance but the spread of disease, as possible sources of infection (e.g. wild birds) cannot reach the sensitive population.

2. Reduction: Weaken your enemy, so it doesn’t spread

The goal of the biosecurity measures is to keep infection pressure beneath the level which allows the natural immunity of the animals to cope with the infections, lowering the pressure of infection e.g. by an effective cleaning and disinfection programme, by the reduction of the stocking density, and by changing footwear when entering a production house.

3. Focus: Hunt the elephant in the room, shoo the butterflies

In each production unit, some pathogens can be identified as of high economic importance. For each of these, it is necessary to understand the likely routes of introduction into a farm and how it can spread within it. Taking into account that not all disease transmission routes are equally important, the design of the biosecurity programme should focus first on high-risk transmission routes, and only subsequently on the lower-risk transmission routes.

4. Repetition: Increasing the probability of infection

In addition to the probability of pathogen transmission via the different transmission routes, the frequency of occurrence of the transmission route is also highly significant when evaluating a risk (Alarcon, et al., 2013). When designing biosecurity programmes, risky actions such as veterinary visits, if repeated regularly must be considered with a higher risk.

5. Scaling: In the multitude, it is easy to disguise

The risks related to disease introduction and spread are much more important in big; more animals may be infected and maintain the infection cycle, also large flocks/herds increase the infection pressure and increase the risk by contact with external elements such as feed, visitors, etc.

CAN WE STILL IMPROVE OUR BIOSECURITY?

Almost 100% of poultry and swine operations already have a nominal biosecurity programme, but not in all cases is it effective or completely effective. BioCheck UGent, a standardised biosecurity questionnaire applied worldwide, shows an average of 65% and 68% of conformity, from more than 1000 broiler and 2000 swine farms between respectively; opportunities to improve can be found in farms globally, and they pay off.

THE BOTTOM LINE

Biosecurity is necessary for disease prevention in any profitable animal production system. To make effective plans, these 5 principles should be applied to choose the right interventions that prevent the entrance and spread of disease. However, maintaining a successful production unit requires a holistic approach in which other aspects of biosecurity need to also be taken seriously, as well as actions to improve in other areas such as management, health and nutrition.

Chicken and Eggs are best for health during COVID19

Foodborne diseases of poultry and related problems

Published on: 9/18/2019

Author/s : Hafez Mohamed Hafez 1 and Hosny El-Adawy 2,3. / 1 Institute of Poultry Diseases, Free University Berlin, Germany; 2 Friedrich-Loeffler-Institut, Institute of Bacterial Infections and Zoonoses, Jena, Germany; 3 Faculty of Veterinary Medicine, Kafrelsheikh University, Kafr El-Sheikh, Egypt.

Summary

In spite of significant improvement in technology and hygienic practices in developed countries at all stages of poultry production accompanied with advanced improvement in public sanitation foodborne diseases remain a persistent threat to human and animal health. Besides the current legislations, the main strategy to control microbial foodborne hazards should include Good Animal Husbandry Practices (GAHPs) at the farm level through sound hygienic measures, which should be applied to poultry houses and environment and the feed. In addition, reducing colonization by using feed additives, competitive exclusion treatment or vaccines is a possibility during transport and slaughtering. In all cases, agent surveillance and monitoring programmes must be adapted and followed strictly in aim to allow early intervention. In addition, the development of antibiotic resistant bacteria will also be a continuous public health hazard

The present paper describes the general the main strategy to control foodborne infections in poultry, with special attention to European legislations toward safe poultry meat.

Introduction

In spite of significant improvements in technology and hygienic practices at all stages of poultry production in developed countries, accompanied by advanced improvement in public sanitation, foodborne diseases remain a persistent threat to human and animal health. Foodborne diseases are still big issues of major concern in those countries. In developing countries, the need to produce sufficient food to meet the requirements of population increases, accompanied by bad economic situations often overshadow the need to ensure safe food products. Regardless of this fact, safe food is a fundamental requirement for all consumers, rich or poor. Food safety is not a discovery of recent times; it is a natural basic instinct of human survival. During human evolution, several approaches were adopted to achieve safety of food. One of the most famous approaches was practiced by several kings which would employ official and well trusted "tasters" that served as food safety sentinels for the kings and royal family members. Food safety and quality of food are currently big issues of major concern.

Many reports during recent years have shown that Salmonella and Campylobacter spp. are the most common causes of human foodborne bacterial diseases linked to poultry. In some areas also verotoxin producing Escherichia coli 0157:H7 (VTEC), Listeria and Yersinia have surfaced as additional foodborne pathogens causing human illness. Several other toxicogenic bacterial pathogens, such as Staphylococcus aureus, Clostridium perfringens, Clostridium botulinum and Bacillus cereus can also enter the human food chain via contaminated poultry carcasses. In addition, the development of antibiotic resistance in bacteria, which are common in both animals and humans, such as Methicillin Resistant Staphylococcus aureus (MRSA) and Extended-spectrum beta-lactamase (ESBL) bacteria, are also an emerging public health hazard.

Salmonella infection

Salmonella infections in poultry are distributed worldwide and result in severe economic losses when no effort is made to control them. In poultry, the genus Salmonella of the family Enterobacteriaceae, which include more than 2500 serovars, can roughly be classified into three categories or groups as follow: Salmonella can also be divided into three groups based on their host specificity and invasiveness [1]. Invasive salmonellas have the capability to “invade” the body from the intestinal lumen and thus infect organs, causing more serious disease. Group 1 contains serovars, which are highly host adapted and invasive. Examples are S. Gallinarum and S. Pullorum in poultry or S. Typhi in humans. Group 2 contains non-host adapted and invasive serovars. Salmonella in this group are of most concern regarding public health, since some of them are capable to infect humans and food producing animals and especially poultry can serve as reservoirs. There are approximately 10 – 20 serovars in this group. Currently, the most relevant serovars of them are S. Typhimurium, S. Enteritidis, S. Heidelberg, S. Hadar as well as S. Arizonae. Group 3 contains non-host adapted and non-invasive serovars, which are harmless for animals and humans. Most serovars of the genus salmonella belong to this group. Some serovars may be predominant for a number of years in a region or country. Then, they disappear and replaced by another serovars [2]. The infection can be transmitted vertically through contaminated eggs laid by infected carriers as well as horizontally spread (lateral). Hatcheries are one of the major sources of early horizontal transmission. Horizontal spread of Salmonella occurring during the hatching was shown in chickens, when contaminated and Salmonella-free eggs were incubated together. Salmonella can also spread through the hatchery by means of contamination of ventilation ducting, belt slots or door seals within hatchers, but may also result from infection and contamination that continuously recycles between hatchers, hatched birds, dust and crate washing equipment. During rearing the infection is transmitted horizontally (laterally) by direct contact between infected and uninfected flocks, and by indirect contact with contaminated environments through ingestion or inhalation of Salmonella organisms. Subsequently, there are many possibilities for lateral spread of the organisms through live and dead vectors. Transmission frequently occurs via faecal contamination of feed, water, equipment, environment and dust in which Salmonella can survive for long periods. Failure to clean and disinfect properly after an infected flock has left the site can result in infection of the next batch of birds. Significant reservoirs for Salmonella are man, farm animals, pigeons, waterfowl and wild birds. Rodents, pet’s insects and litter beetles (Alphitobius diaperinus) are also potential reservoirs and transmit the infection to birds and between houses [3]. Probably one of the most common sources for lateral spread of the organisms is feed. Nearly every ingredient ever used in the manufacture of poultry feedstuffs has been shown at one time or another to contain Salmonella. The organism occurs most frequently in protein from animal products such as meat and bone meal, blood meal, poultry offal, feather meal and fishmeal. Protein of vegetable origin has also been shown to be contaminated with Salmonella [4, 5].

Since November 2003, several regulations from the European Parliament Council Regulation on the control of salmonella and other specified food-borne zoonotic agents were passed. This regulation covers the adoption of targets for the reduction of the prevalence of specified zoonosis in animal populations at the level of primary production, including breeding flocks (Chickens and turkeys), layers, broiler and turkey flocks. Food business operators must have samples taken and testing for the zoonosis and zoonotic agents especially Salmonella (Table 1) as summarized by Hafez (2010) [6].

 

 

Campylobacters

Thermophilic campylobacters are the most common bacterial cause of diarrhoea in humans worldwide. Enteric diseases caused by the thermophilic species C. jejuni, C. coli, C. lari, and C. upsaliensis range from asymptomatic infections to severe inflammatory bloody diarrhoea. The natural habitat of thermophilic Campylobacter is the intestinal tract of healthy birds and raw meat that can be contaminated during the slaughtering process [7]. It is estimated that as many as 90% of broilers and turkeys may harbour Campylobacter while showing little or no clinical signs of illness [8]. Poultry and poultry products remain the most common source of foodborne human campylobacteriosis. The major route for Campylobacter infection in poultry appears to be the horizontal transmission from the environment. Specific flocks that become infected show rapid rate of intra-house transmission and a high isolation rate from caecal swabs, water and litter. Campylobacter spp. are widespread in poultry not only during the growing period, but also on the poultry meat during slaughter and during processing of poultry products. Horizontal transmission is the most important mode of the introduction of Campylobacter into poultry flocks. However, the ability of Campylobacter to spread is limited by their relatively low tenacity, which can vary between strains. Especially dry environments kill Campylobacter within one or two hours [9].

 

Antibiotic resistant

The development of antibiotic resistance in bacteria, which are common in both animals and humans, is an emerging public health hazard. Controlling these foodborne organisms requires a broader understanding of how microbial pathogens enter and move through the food chain, as well as the conditions that promote or inhibit growth for each type of organism.

Multi-resistant bacteria are increasingly posing a hazard to human and animal health worldwide, impeding successful antibacterial treatment [10, 11]. In addition, the development of novel antibiotics does not keep step with the emergence of antimicrobial resistance in bacteria [12].

Among multi-resistant bacteria, vancomycin-resistant enterococci (VRE) have been estimated as one of the most common bacteria causing a rise in cases of nosocomial infections in humans in the last few years [10]. The prevalence of vancomycin-resistant enterococci (VRE) in 20 turkey flocks reared in the southwest of Germany was investigated. Enterococci were tested on the presence of the vancomycin resistance genes vanA, vanB (B1/B2/B3), and vanC (C1/C2/C3). Vancomycin-resistant enterococci were detected in 15 (75%) of the 20 turkey flocks investigated. In a total 68 isolates were isolated from birds and dust samples, enterococci bearing van-genes were detected. Of these, 12 isolates carried the vanA gene (17.6%) and 56 isolates carried the vanC1 gene (82.6%). Neither vanB (B1, B2, B3) genes nor the vanC2 or vanC3 genes could be detected [13].

In addition, Livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) have been isolated from a number of livestock species and persons involved in animal production. Turkey meat was also showed to be contaminated with MRSA [14]. Richter et al. investigated the prevalence of LA-MRSA in fattening turkeys and people living on farms that house fattening turkeys [15]. Eighteen (90%) of 20 investigated flocks were positive for MRSA. All-female flocks were positive, while 8 male flocks were positive. On 12 of the farms 22 (37.3%) of 59 persons sampled were positive for MRSA. None of them showed clinical symptoms indicative of an MRSA infection. People with frequent access to the stables were more likely to be positive for MRSA. In most flock’s MRSA clonal complex (CC) 398 were detected. In five flock’s MRSA of spa-type t002 were identified, which was not related to CC398. Moreover, other methicillin-resistant Staphylococcus spp. were detected on 11 farms and in 8 people working on the farms. Similar results were about MRSA in turkeys were published by El-Adway et al. [16].

Maasjost et al. investigated the antimicrobial susceptibility patterns of Enterococcus faecalis and Enterococcus faecium isolated from poultry flocks in Germany and they found that high resistance rates were identified in both Enterococcus species for lincomycin (72%–99%) and tetracycline (67%–82%) [17]. Half or more than half of Enterococcus isolates were resistant to gentamicin (54%–72%) and the macrolide antibiotics erythromycin (44%–61%) and tylosin-tartate (44%–56%). Enterococcus faecalis isolated from fattening turkeys showed the highest prevalence of antimicrobial resistance compared to other poultry production systems.

El- Adway et al. investigated 76 C. jejuni isolates were recovered from 67 epidemiologically unrelated meat turkey flocks in different regions of Germany in 2010 and 2011 [18]. Only one isolate was sensitive to all tested antibiotics. The numbers of isolates that were sensitive to streptomycin, erythromycin, neomycin, and amoxicillin were 69 (90.8%), 61 (80.2%), 58 (76.4%), and 44 (57.9%), respectively. The emergence of a high resistance rate and multidrug resistance to three or more classes of antimicrobial agents were observed. The resistance against sulphamethoxazole/trimethoprim, metronidazole, ciprofloxacin, naladixic acid, and tetracycline was 58 (76.3%), 58 (76.3%), 53 (69.7%), 51 (67.1%), and 42 (55.3%), respectively. Multidrug resistance to three or more classes of antimicrobial agents was found and ranged from 3.9% to 40.8%. Similar results were also found by examination of isolates collected from different free-range turkey flocks in Germany [19].

General approaches to control foodborne infections

To control the foodborne organisms, information is required to understand more fully, how microbial pathogens enter and move through the food chain, and the conditions, which promote or inhibit growth for each type of organism. In general, the main strategy to control foodborne infections in poultry should include monitoring, cleaning the production chain from the top, especially for vertically transmitted microorganism such as Salmonella by culling infected breeder flocks, hatching egg sanitation and limiting introduction and spread of infections at the farm level through effective hygiene measures [20-22]. An intensive and sustained rodent control is essential and needs to be well planned and routinely performed and its effectiveness should be monitored. In addition, reducing bacterial colonization by using feed additives such as short chain organic acids (formic acid, propionic acid), carbohydrates (lactose, mannose, galactose, saccharose), probiotics, competitive exclusion or use of vaccines are further possibilities [23, 24]. Live and inactivated vaccines are used to control Salmonella in poultry [25]. Generally, vaccination alone is of little value, unless it is accompanied by improvements in all aspects of management and biosecurity. In addition, further attention must be paid to the development of efficient vaccines against campylobacter infections.

Suggested link

Since the success of any disease control programme depends on the farm and personal sanitation, it is essential to incorporate education programmes about micro-organisms, modes of transmission as well as awareness of the reasons behind such control programmes by people involved in poultry production. In addition, effective education programmes must be implemented to increase public awareness of the necessary measures to be taken for protection against bacteria in food products from poultry.

Furthermore, in spite of significant improvement in technology and hygienic practices at all stages of food production accompanied with advanced improvement in public sanitation foodborne infections remains a persistent threat to human and animal health. The failure of the human population to apply hygienically acceptable food handling and cooking practice, and the fact that the processing plants are not able to reduce the level of pathogenic bacteria in poultry products, mean that every effort must be made to reduce the Salmonella contamination of the live birds before despatch to processing plants. New approaches to the problem of contamination must be adopted and the discussion on the decontamination of the end product must be re-evaluated carefully and without emotion. In addition, research must continue to find additional control and preventive means. Furthermore, the long term, development of poultry lines that are genetically resistant to some pathogens should be progressed.

 

Conclusions

Toward food safety in the EU several legislations are into force and their aims can be summarized according to Mulder (2011) as follows [26]:

1. Safety (consumer health): by new methods to reduce the use of antibiotics/medicines; improve disease resistance; zoonosis control; traceability of animals and products
2. Safety (product safety): stimulate and control hygienic processing, traceability of products and materials intended to come into contact with food
3. Animal welfare: animals kept according to rules/systems
4. Product quality: improved quality and composition; quality and chain control systems; traceability of animals and products.
5. Environment: reducing environmental contamination, Nitrogen and Phosphorous. There is a critical look at the use of by-products of human food production. The re-use of by-products for non-food applications (feathers) should be encouraged.
6. Rural impact, economic effects and biodiversity.

Factors affecting vitamin stability in animal feed

There are a number of factors affecting vitamin stability in animal feeds. These factors may vary depending on whether the vitamins are naturally occurring in the feed materials, or added to the diet in a premix form.

The following is a discussion of these factors in either case, together with the strategies to be adopted for improving the stability and utilisation of the dietary vitamins by animals.

Symptoms of a vitamin A deficiency include reproductive problems in both males and females. Photo: Henk Riswick

Forage plays a significant role in the supply of vitamins to ruminants. However, the vitamin content of forages is highly variable and unpredictable due to the following stability factors:

Forage species

Grasses generally have the lowest level of ᵦ-carotene (146 mg/ kg DM) while legumes have the highest level (438 mg kg21 DM). The differences in the level of ᵦ-carotene are mainly due to the ratio of leaf to stem in the plant and capacity of the plant to synthesize carotene

Stage of maturity

The levels of ᵦ-carotene and 𝛼-tocopherol in the grasses and legumes are very high in the young stages and reduce as the plant matures. At maturity, plants may have 10% (in the case of grasses) to 40% (for legumes) of the value of the carotene of immature plants. The principal factor responsible for the variation in levels of ᵦ-carotene and 𝛼-tocopherol of forages in the course of their maturation is the change in the ratio of leaf to stem because the leaves are considerably richer in these vitamins than the stems. The formation of stems is accompanied by an increase in the concentration of DM; there is thus a negative correlation between the DM content and the level of ᵦ-carotene.

 

Climatic conditions

For a given stage of growth, a forage is richer in ᵦ-carotene and 𝛼-tocopherol when grown under rainy conditions with a low temperature. The positive influence of these conditions is related to the increase in the leaf-to-stem ratio which contributes more to the increased level of ᵦ-carotene 𝛼-tocopherol.

Haymaking

Drying crops either on the ground or in barns reduces the vitamin levels. It was found that in excess of 80% of carotene from clover was lost during the first 24 hours of sun-drying and was practically zero when the crop was dried for 4–5 days in the sun. Forages exposed to rain and then dried in the sun have less ᵦ-carotene than sun-dried forage. Thus, if the forage rests exposed to the sun for an extended period of time and at the same time is exposed to several showers, the destruction of ᵦ-carotene is nearly complete.

 

Ensiling

Stability of some vitamins such as vitamin A may be adversely affected if mouldy or spoiled silages are fed for long periods. Symptoms of a vitamin A deficiency include reproductive problems in both males and females. Pregnant cows may abort, retain their placenta, and develop a uterine infection or give birth to weak, dead, or blind calves. Bulls with a vitamin A deficiency produce semen with low numbers of sperm and high numbers of abnormalities. To prevent moulds from developing in silage, production practices that preserve quality should be strictly followed. Accepted silage-production practices include:

• Harvesting at the proper moisture content (30-35 %)
• Chopping uniformly at the proper length to allow for better compaction and exclusion of air
• Silo size should be matched to herd size to ensure daily removal of silage at a rate faster than deterioration can occur
• Filling the silo rapidly
• Packing the silage sufficiently
• Covering the horizontal silo immediately during or after filling
• Using silage additives (such as ammonia, propionic acid, microbial cultures, or enzymatic silage) may be beneficial in preventing mould growth.

With the advent of intensive livestock production, the production of synthetic vitamins in a premix form was essential due to the variable and unpredictable vitamin content of forages.

Stability of the synthetic vitamins may, however, be influenced by the following factors:

Composition of the premix

Vitamins are quite sensitive to their physical and chemical environment, with oxidation-reduction reactions due to contact with trace minerals being the predominant cause of vitamin instability. The type of trace mineral can have a significant effect on vitamin stability. Free metal ions, sulfates, carbonates, and oxides (the primary forms of inorganic trace minerals used) are the most reactive, while chelates (a classification of organic trace minerals) are the least responsive. Therefore, the current practice of over-fortification with inorganic trace minerals can inadvertently have a negative effect on vitamin stability and, thus, negatively impact animal health and performance indirectly.

Pelleting

Pelleting is typically the most aggressive process against vitamins due to exposure to heat. There is, however, little or no vitamin destruction with pelleting temperatures of up to 80°C. At higher pelleting temperature, chemical modification can enhance the stability of some vitamins such as vitamin C which is easily oxidised and destroyed in this case. The esterification of the 2-carbon atom of L-ascorbic acid with phosphate protects L-ascorbic acid from oxidation. Coatings or encapsulation with carbohydrate, protein, or ethyl cellulose gives vitamins such as vitamin A and D3 greater protection against heat, moisture, and pressure during pelleting.

Storage

Premixes containing vitamins can be stored for about 3 to 4 months. However, storage time should not exceed 60 days if choline and trace minerals are present in combination with vitamins in the premix. Also, the use of barriers such as plastic-lined bags aid in reducing the absorption of moisture, thereby improving vitamin stability.