ANTIBIOTIC RESISTANCE IN FISH FARMING ENVIRONMENTS: A GLOBAL CONCERN

ANTIBIOTIC RESISTANCE IN FISH FARMING: A GLOBAL CONCERN

Antibiotic Resistance in Fish Farming

The occurrence and distribution of antibiotic resistance (AR) phenomena in areas designed for fish Farming has exponentially increased in the last decades. AR bacteria have become a global concern due to the massive use or misuse of antibiotics to prevent possible diseases and overcome major production problems, as confirmed by several research reports. As a consequence of the selective pressure exerted by antibiotics, ARB has been developed and multi-drug resistant bacteria (MDR) have become difficult to be controlled and eradicated. Their spread is expected to increase and is recognized to represent one of the most serious threats to public health in this century. Compared to the past, in salmonid farming in Europe and America, an effective range of vaccines has been developed, which have allowed decreasing the use of antimicrobial agents for most of the bacterial diseases . In addition, the husbandry methods and diagnostic techniques have been improved and this has resulted in a more effective control of bacterial pathogens and reduced impacts of fish diseases. However, for some bacterial diseases, no vaccines are available yet and antimicrobials are still used as a prophylactic measure.

This short note aims at drawing a synthesis of the AR occurrence in aquaculture field and of the possible causes for its spread, suggesting the related legislative measures and the possible solutions to this emerging problem, which has been recognized as a research priority issue by the European Community.

Since the first case studies, several reports have documented the occurrence and spread of ARB in both marine and freshwater fish farms . Most frequently, AR has been reported against oxytetracycline , tetracycline , ampicillin  florfenicol. On the contrary, bacteria resistant to gentamicin, kanamycin, flumequine and enrofloxacin have been reported to account for a low percentage of the total of the isolates.

Fish feed have been claimed to be a source of antimicrobialresistant bacteria. Concerning the mechanisms of AR, two main pathways have been suggested : a) inherent or intrinsic resistance, which occurs when a bacterial species is not normally susceptible to an antibacterial agent, due to the inability of this agent to reach its target site inside the cell, or a lack of affinity between the antibacterial and its target site, or b) acquired resistance, when the bacterial species is normally susceptible to a particular drug, but some strains are resistant and proliferate under the selective pressure induced by the use of that agent. AR genes can be transferred between bacteria by transformation; transduction or conjugation processes that involve lateral DNA transfer. Therefore, bacterial AR is a natural defence mechanism realized through genetic modifications triggered to survive to the drug action and in many conditions, mechanisms of horizontal gene transfer have been reported to be responsible for the spread and dissemination of the genetic material bearing AR among different bacterial species. Even in some aquaculture systems of Pakistan and Tanzania where antibiotics were not previously used ; explained the occurrence of AR against various antimicrobials hypothesizing that a pool of resistance genes derived from integrated fish farming practices based on the use of domestic farm and poultry waste along with antibiotic residues from animal husbandry.

The public health hazards related to antimicrobial use in fish farming include, on one hand, the development and spread of AR bacteria and resistance genes, and on the other, the presence of antimicrobial residues both in the environment and in aquaculture products. Since animals and animal waste are a potential reservoir of multi resistance genes that can be transmitted directly or indirectly to humans through contact and food consumption, this can represent a risk to public health. However, the opinions on the possible risks of transfer of such resistances to human consumers are controversial. Antibiotic-resistant bacteria that persist in sediments and farm environments can act as sources of antibiotic-resistance genes for fish pathogens in the vicinity of the farms.

With respect to the legislative issues of the AR in fish farming, this issue has been recognized as a global concern by the Council and the European Parliament, as well as by the EU Commission. The Regulation (EC) No 470/2009 established the antibiotic maximum residue limits (MRL) in foodstuff of animal origin, taking into account the toxicological risks and the pharmacological effects of residues. The recently launched research programme Horizon 2020, in the framework of the Societal Challenge 3.2 (Food Security, Sustainable Agriculture and Forestry, Marine, Maritime and Inland Water Research and the Bioeconomy), promotes the reduction of antibiotics in animal farming and the setup of measures to prevent their spread, to increase agriculture environmental sustainability. This underlines the relevance of AR in fish farming as a problem with significant scientific, social and economic impacts.

In 2011, a 5-year Action Plan was launched to address the growing risks posed by AR based on a holistic approach; a prudent use of antimicrobial in veterinary medicine was recommended. To comply with this Action, in 2015 specific guidelines have been issued (2015/C 299/04, Commission Notice-Guidelines for the prudent use of antimicrobials in veterinary medicine), with the aim of limiting AR bacteria originated from livestock animals. Among the actions recommended to prevent and reduce the use of antimicrobials in aquaculture, it has been underlined to encourage the use of vaccines, when possible; to implement specific biosecurity measures and to develop specific disease surveillance programmes to prevent or reduce possible disease outbreaks; to develop production systems optimal with respect to water quality, oxygen levels and able to warrant the welfare of the reared animals.

Compared to the studies available until now on the antibiotic use in aquaculture or other farm environments and the presence of AR, relatively few studies focused on the possible solutions to this problem. To implement the appropriate control strategies, a clear evidence of the link between abuse of antibiotics in aquaculture, antibiotic resistance in bacterial pathogens and antibiotic residues is needed. In order to contain and manage the emergence of AR, several solutions can be suggested, that aim at the development of sustainable aquaculture practices, such as those including the use of probiotics, essential oils to increase fish immune status of fish, as well as the adoption of measures able to warrant the fast abatement of antimicrobial residues in animal wastes (The Review on Antimicrobial resistance 2015). Particularly, the use of probiotics to promote health maintenance and disease prevention has recently gained an increasing interest as an alternative to antibiotics. Supplementation with pro- and prebiotics in fish nutrition is increasing in parallel with increasing demand by consumers and with the need for environmentally friendly aquaculture practices. The beneficial effects of probiotics in fish and shellfish culture – improved growth performance, activity of gastrointestinal microbiota and feed utilization, enhanced immunity and disease resistance – have recently been reviewed. Most probiotics proposed as biological control agents in aquaculture belong to the lactic-acid bacteria (LAB), the genus Bacillus, or the genera Pseudomonas and Burkholderia.

Another possible solution to chemotherapies in aquaculture is related to the use of vegetable extracts. Herbal extracts from plants or algae are known to contain natural compounds, such as phenolic compounds, polysaccharides, proteoglycans and flavonoids which are able to stimulate the fish immune system and therefore may play a major role in the prevention or control of infectious microbes.These are recognized as eco-friendly alternatives for therapeutic and prophylactic purposes in health management of aquatic animals, which combine sustainable production systems with high quality of seafood products; nevertheless, further studies are needed to assess any potential impact of these substances on the host microbiota and on the environment.

About the treatment of aquaculture effluents, antibiotic residues should be removed before being released to the environment. Physical, chemical, and biological methods including adsorption, biodegradation, disinfection, membrane separation, hydrolysis, photolysis, and volatilization have been applied in aquaculture systems to remove antibiotics. Tetracyclines are removed mainly by adsorption onto the biomass flocs; beta-lactams by hydrolysis reactions driven by bacteria or physical chemical processes, while removal of erythromycin and ciprofloxacin by biodegradation is difficult. Advanced oxidation processes have been found to be cost-effective mechanisms for the abatement and removal of flumequine from aqueous systems, as conventional processes in wastewater treatment plants fail to remove this antibiotic.

In synthesis, on the basis of the experimental evidences proving the spread of AR, the best way to solve this problem is to avoid abuse antibiotic use in aquaculture. A holistic approach to the use of antibiotics in fish farming is suggested, which relies on reducing the need for antibiotics through prevention (i.e. vaccines), nutrition, and better management of rearing sites.

Source: http://www.fisheriessciences.com/fisheries-aqua/antibiotic-resistance-in-fish-farming-environments-a-globalconcern.php?aid=11240

Heat stress in poultry

                 

What oxidative stress has to do with it, why it affects gut health, and how phytomolecules support mitigation strategies

Stress in animals can be defined as any factor causing disruptions to their homeostasis, their stable internal balance. Stress engenders a biological response to regain equilibrium (1). We can distinguish four major types of stress in the poultry industry: technological or management-related stress; environmental stress; nutritional stress, including due to heavy metals, mycotoxins, and low-quality ingredients; and internal stress, which is related to health status and health challenges. (2). All types of stress lead to molecular and cellular changes that decrease health and productivity.

Climate change, thermoregulation, and stress

High environmental temperatures are among the most important environmental stressors for poultry production, causing significant economic losses in the industry (3). Climate change has increased the prevalence and intensity of heat stress conditions in most poultry production areas all over the world (4, 5).

The optimum temperature for poultry animals’ well-being and performance – the so-called thermoneutral zone – is between 18 and 22°C. When birds are kept within this temperature range, they do not have to spend energy on maintaining constant body temperature (6).

Heat stress is the result of unsuccessful thermoregulation in the animals, as they absorb or produce a higher quantity of heat than they can lose. It means that there is a negative balance between the net amount of energy flowing from the animal to the environment and the energy it produces (7).

HEAT STRESS – CONTRIBUTING FACTORS

This energy imbalance is influenced by environmental factors such as sunlight, thermal irradiation, air temperature, humidity, and stocking density, but also by animal-related factors such as body weight, feather coverage and distribution, dehydration status, metabolic rate, and thermoregulatory mechanisms (7, 8). When the environmental temperature is above the thermoneutral zone, the animals activate thermoregulation mechanisms to lose heat through behavioral, biochemical, and physiological changes and responses (9-12).

Heat stress can be classified into two main categories, acute and chronic. Acute heat stress refers to a short and fast increase in environmental temperature (a few hours), whereas under chronic heat stress the high temperatures persist for more extended periods (several days).  Some studies suggest that, in some circumstances, poultry animals show a degree of resilience to acute heat stress (7, 9, 10). However, in the long run, their compensatory mechanisms are not sufficient to maintain tissue integrity and thus health and performance (11).

The animal’s response to heat stress

The exposure of poultry to heat stress changes the gene expression of cytokines, upregulates heat shock proteins (HSP), and reduces the concentration of thyroid hormones (10, 12). When heat stress persists, these cascades of cellular reactions result in tissue damage and malfunction. The animals exposed to heat stress suffer adverse effects in terms of performance, which are widely known and include high mortality, lower growth and production (Figure 1), and a decline in meat and egg quality (13, 14).

Figure 1 - Body weight gain in heat stressed broilers 

Figure 1: Body weight gain of broilers exposed to chronic heat stress (35°C continuously from day 21). A marker for tight junction permeability was added to feed (FITC-d – fluorescein isothiocyanate dextran); its fluorescence (in serum) increased with heat stress exposure time, showing higher intestinal permeability. (Adapted from Ruff et al., 2020)

OXIDATIVE STRESS – A CONSEQUENCE OF HEAT STRESS

Oxidative stress, simply put, occurs when the amount of reactive oxygen species (ROS – such as superoxide anions, hydrogen peroxide, and hydroxyl radicals) exceeds the antioxidant capacity of the cells (6, 14, 15). Oxidative stress is regarded as one of the most critical stressors in poultry production as it is a response to diverse challenges affecting the animals (2, 17).

At a cellular level, the metabolism of the animal – its energy production – generates ROS and reactive nitrogen species (RNS), such as hydroxyl radicals, superoxide anions, hydrogen peroxide, and nitric oxide. These usually are further processed by antioxidant enzymes produced by the cell (2, 15), including superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px). Nutrients such as selenium and vitamins E, C, and A also participate in antioxidant processes (2, 5). When the generation of ROS exceeds the capacity of the antioxidant system, oxidative stress ensues (2, 16).

Heat stress leads to higher cellular energy demand, promoting the generation of ROS in the mitochondria (13), which exceeds the antioxidant capacity of the organism. Consequently, oxidative stress occurs in several tissues, leading to cell apoptosis or necrosis (11). Among these tissues, the gastrointestinal tract can be highly affected.

Oxidative stress damages cell proteins, lipids, and DNA, and reduces energy generation efficacy (6). Moreover, oxidized molecules can take electrons from other molecules, resulting in a chain reaction. If not controlled, this reaction can cause extensive tissue damage (16).

In response to oxidative stress, all antioxidants in the organism work together to re-establish homeostasis. Several steps in the oxidative stress response have been identified. Whether they take place depends on the intensity of the stressor, with ROS and RNS acting as signaling molecules. These steps include the internal synthesis of antioxidants, the activation of transcription factors or vitagenes, and the production of protective molecules (Figure 2).

Figure 2 - Summary of the antioxidant response

Figure 2: Summary of the antioxidant response

First, decrease free radical production by decreasing oxygen availability and reducing the activities of enzymes responsible for ROS production (NADPH oxidase). Second, scavenge and decompose free radicals through natural antioxidants (vitamins E & C, GSH, SOD, GPx, and CAT). Third, activate Nrf2 and vitagenes to further stimulate the synthesis of antioxidants. Fourth, activate enzymatic systems responsible for damaged molecule repair (HSP, Msr, DNA-repair enzymes) and removal (PH–GPx). Fifth, induce apoptosis and other processes to deal with terminally damaged cells.

(Adapted from Surai et al., 2019)

Oxidative stress’ effects on the gut

In the gastrointestinal tract, oxidative stress and the consequent tissue damage lead to increased intestinal permeability. This facilitates the translocation of toxins and pathogens from the intestinal tract into the bloodstream (Figure 3).

Under oxidative stress conditions in the gut, there is a demand for antioxidants to counteract the excess of ROS; hence, dietary antioxidants can help reduce ROS and improve animal performance (15). Research shows that certain phytomolecules have antioxidant properties and improve performance under conditions of oxidative stress (14, 18-20).

Figure 3

 

Thermoregulation: changes in blood flow

The gastrointestinal tract is profoundly affected by heat stress: to help with heat dissipation, the thermoregulatory mechanism of the animal shifts visceral blood flow towards peripheral circulation. Organ ischemia and hypoxia follow, limiting gut motility, nutrient utilization, and feed intake (5, 14). Enterocytes are particularly sensitive to hypoxia and nutrient restriction, which leads to oxidative stress (2, 12).

Changes in intestinal barrier’s tight junctions

Several studies indicate that both acute and chronic heat stress increase gut permeability, partly by increasing oxidative stress and by disrupting the expression of tight junction proteins (5, 21). Heat and oxidative stress in the gut result in intestinal cell injury and apoptosis. When the tight junction barrier is compromised, luminal substances leak into the bloodstream, which constitutes the condition described as “leaky gut” (4, 21).

Changes in intestinal morphology

Heat stress affects intestinal weight, length, barrier function, and microbiota, resulting in animals that have lower total and relative weight of the small intestine, with shorter jejunum and duodenum, shorter villi (Figure 4), and reduced absorption areas, in comparison to non-stressed animals (11, 12, 23-26).

Figure 4 - Dudenum morphology (villous height and width as % of the control group) in heat-stressed broilers

Figure 4: Villous height and width of broilers exposed to heat stress in relation to the control group (100%). Villous height is always shorter than the control group, but the width can increase when the organism shows resilience to the stressful situations and aims to recover the intestinal surface. (Adapted from Jahejo et al., 2016; Santos et al., 2019; Wu et al., 2018; Abdelqader et al., 2016; Santos et al., 2015 and Awad et al., 2018 – by order of appearance in the graph, from left to right)

Changes in the intestinal microbiome

Due to reduced feed intake and impaired intestinal function, the presence and activity of the commensal microbiota can also be modified. Heat stress can lead to reduced populations of beneficial microbes. At the same time, it can boost the growth of potential pathogens and lead to dysbiosis, increased gut permeability, as well as immune and metabolic dysfunction (27). Burkholder et al. (2008) and Rostagno (2020) point out that pathogens such as Clostridia, Salmonella, and coliform bacteria increase in poultry exposed to heat stress, while the populations of beneficial bacteria such as Lactobacilli and Bifidobacteria decrease.

Necrotic enteritis

Heat stress causes damage in the gut microbiota, intestinal integrity, and villus morphology, as well as immunosuppression. Consequently, feed digestion and absorption decline (11, 12, 28, 29). These factors increase the risk of necrotic enteritis outbreaks (5, 28, 30, 31), one of the most problematic bacterial diseases in modern poultry production.

In a study by Tsiouris et al. (2018), cyclical acute heat stress was found to increase the incidence and severity of necrotic enteritis in broilers challenged with C. perfringens and to produce the disease in animals that were not exposed to the bacteria. Other signs, such as growth retardation and a reduced pH of the intestinal digesta, were also observed in the heat-stressed birds.

By lowering feed digestibility, increasing gut permeability, and compromising immunity, heat stress leaves animals more susceptible to gut-health related issues such as dysbacteriosis and necrotic enteritis – and thus increases the need to use antibiotics.

Mitigation strategies

Most intervention strategies deal with heat stress through a wide range of measures, including environmental management, housing design, ventilation, sprinkling, and shading, amongst others (8). Understanding and controlling environmental conditions is always a part of heat stress management: it is crucial for ensuring animal welfare and achieving successful poultry production.

Feed management and nutrition interventions are also recommended, together with environmental management, to reduce the effects of heat stress. They include feeding pelletized diets with increased energy, higher fat inclusions, reduction of total protein, supplemental amino acids, higher levels of vitamins and minerals, and adjusting the dietary electrolyte balance (1, 12, 18). Nutrition is crucial, and the use of the right diet aids in attenuating heat stress in birds.

Phytomolecules: powerful antioxidants

It is practically impossible to avoid stress in commercial poultry production; hence it is common for animals to experience oxidative stress at times. Phytomolecules are natural antioxidants with anti-inflammatory and digestive properties (8, 14), which have been shown to improve poultry performance, including during challenging periods. The antioxidant capacity of phytomolecules manifests itself in free radical scavenging, increased production of natural antioxidants, and the activation of transcription factors (2, 32, 33).

As compounds that have low bioavailability, they can remain at high concentrations within the intestine, when provided at the appropriate dosage and through encapsulation technology. Research has found that phytomolecules can effectively reduce intestinal ROS and thus alleviate heat stress in poultry (15, 18-20), specifically mitigating oxidative stress in the intestine.

One heat stress study, for example, found that carvacrol elevates serum GSH-PX activity, compared to non-supplemented broilers (19). Other studies demonstrate that cinnamaldehyde also increases the activities of natural antioxidants in heat-stressed broilers (32, 35). A study by Prieto and Campo (2016) showed that dietary supplementation of capsaicin effectively alleviated heat stress, as indicated by a lower H/L ratio in supplemented animals.

Silibinin, a flavonolignan present in silymarin (milk thistle extract), is another powerful antioxidant. In the gastrointestinal tract, it can come into direct contact with cells, activating transcription factors such as Nrf2, and thus helping to upregulate the antioxidant protection (34). Other phytomolecules, such as menthol and cineol, also aid animals under heat stress by simulating the sensory cold receptors of the oral mucosa. This gives them a cooling sensation and reduces heat stress behavior (18).

Summary

Heat stress is a common reality in poultry production, its effects are quite complex and harmful and depend on the intensity and duration of the exposure to high temperatures.

The gut is affected by heat stress through several pathways, including organ ischemia and hypoxia, as well as oxidative stress.

In heat stress challenges, the intestinal barrier is compromised because of lower tight junction protein expression, enterocyte damage, and microbiome unbalance, leading to gut health issues such as dysbiosis and necrotic enteritis.

At the gut level, phytomolecules such as carvacrol, cinnamaldehyde, capsaicin, silymarin, cineol, and menthol, among others, have been found to alleviate heat stress through their antioxidant capacities, leading to improved animal health and performance.

By Marisabel Caballero (Global Technical Manager Poultry – EW Nutrition) & Guillermo Gaona (Regional Technical Manager LATAM – EW Nutrition)

Antibiotics Interaction

Importance of high-level biosecurity

Authors: Marisabel Caballero, Global Technical Manager Poultry, and Fellipe Freitas Barbosa, Global Technical Manager Swine, EW Nutrition.

Biosecurity is the foundation for all disease prevention programs (Dewulf, et al., 2018), and one of the most important points in antibiotic reduction scenarios. It includes the combination of all measures taken to reduce the risk of introduction and spread of diseases. It is based on the prevention of and protection against infectious agents by understating the disease transmission processes.

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  (Davies & Wales, 2019).

LOWER USE OF ANTIMICROBIALS WITH HIGHER BIOSECURITY

Several studies and assessments relate that high farm biosecurity status and/or improvements in biosecurity lead to reduced antimicrobial use (Laanen, et al., 2013, Gelaude, et al., 2014, Postma, et al., 2016, Collineau, et al., 2017 and Collineau, et al., 2017a). Laanen, Postma, and Collineau studied the profile of swine farmers in different European countries, finding a relation between the high level of internal biosecurity, efficient control of infectious diseases, and reduced need for antimicrobials.

Reports on reduction on antibiotic use due to farm interventions are also available. Gelaude, et al. (2014), evaluated data from several Belgian broiler farms, finding a reduction of antimicrobial use by almost 30% within a year when biosecurity and other farm issues were improved. Collineau et al. (2017) studied pig farms in Belgium, France, Germany, and Sweden, in which the use of antibiotics was reduced on average by 47% across all farms. The researches observed that farms with the most strict biosecurity protocols, higher compliance, and who also took a multidisciplinary approach (making other changes, e.g. in management and nutrition), achieved a greater reduction of antibiotic use.

BIOSECURITY INTERVENTIONS PAY OFF

Of course, the interventions necessary to achieve an increased level of biosecurity carry some costs. However, the interventions have proven to also improve productivity. Especially if taken with other measures such as improved management of newborn animals and nutritional improvements. The same studies which report that biosecurity improvements decrease antibiotics 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) reported a reduction in mortality in pigs during both the pre-weaning and fattening period of 0.7 and 0.9 percentual points, respectively.

EXECUTION

Although biosecurity improvements and other interventions necessary for antibiotic reduction programs are well known,  continuous compliance of these interventions is often low and difficult. The implementation, application, and execution of any biosecurity program involve adopting a set of attitudes and behaviors 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 to improve health of animals and people, and a piece of the multidisciplinary approach to reduce antibiotics and improve performance.

DESIGNING EFFECTIVE BIOSECURITY PROGRAMS: CONSIDER FIVE PRINCIPLES

When designing or evaluating biosecurity programs, we can identify five principles that need to be applied (Dewulf, et al., 2018). 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 definition of the perimeter of the farm, a separation between high and low-risk animals, and dirty and clean internal areas on the farm. This avoids not only the entrance but the spread of disease, as possible sources of infection (e.g. animals being introduced in the herd and 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 (Dewulf, et al., 2018). Lowering the pressure of infection e.g. by an effective cleaning and disinfection program, 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 due to their harm and frequency. For each of these, it is even more important, to understand the likely routes of introduction into a farm and how it can spread within it. Taking into consideration that not all disease transmission routes are equally significant, the design of the biosecurity program should focus first on high-risk pathogens and transmission routes, and only subsequently on the ones lower-risk (Dewulf, et al., 2018).

4.    Repetition: When the danger is frequent, the probability of injury is increased

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 programs, 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 farms (Dorea, et al., 2010); 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 program, but not in all cases is it fully effective. BioCheck UGent, a standardized biosecurity questionnaire applied in swine and broiler farms worldwide, shows an average of 65% and 68% in conformity, respectively, from more than 3000 farms between both species (UGent, 2020). Therefore, opportunities to improve can be found in farms globally, and they pay off.

To find these opportunities, consider three situations you need to know:

1. Know your menace: Identify and prioritize the disease agents of greatest concern for your production system by applying the principles of focus and repetition. Consider the size of the facility when evaluating risks applying the scaling
2. Know your place: Conduct an assessment of the facility. A starting point is to define the status quo. For that, operation-existing questionnaires or audits can be used. However, the “new eyes principle” should be applied and an external questionnaire such as BioCheck UGent (biocheck.ugent.be) is recommended. The questionnaire will help you identify gaps in your biosecurity plan as well as processes that may be allowing pathogens to enter or move from one location to another, and measures that can be implemented applying the principles of separation and reduction.
3. Know your processes: Implement processes and procedures that apply the biosecurity principles and help to eliminate, prevent, or minimize the potential of disease. A deep evaluation of the daily farm processes will aid in risk mitigation, considering, among others, movement of personnel, equipment, and visitors, the entrance of pets, pests and vermin, dealing with deliveries and handling of mortality and used litter.

COMPLIANCE – THE WEAK LINK IN BIOSECURITY PROGRAMS

Achieving systematic compliance of biosecurity protocols on a farm is a complex, interactive, and continuous process influenced by several factors (Delabbio, 2006) and an ongoing challenge for animal production facilities (Dewulf, et al., 2018). Thus, it is clear that the biosecurity plan can only be effective if everyone on the operation follows it constantly, i.e. if everyone performs in compliance.

Compliance can be defined as the extent to which a person’s behavior coincides with the established rules. Thus, compliance with biosecurity practices should become part of the culture of the facility. Poor compliance in relation with biosecurity can be connected to:

• Lack of knowledge or understanding of the biosecurity protocols (Alarcon, et al., 2013; Cui & Liu, 2016; Delpont, et al., 2020)
• Lack of consequences for non-compliance (Racicot, et al., 2012a)
• A company culture of inconsistent or low application of biosecurity protocols (Dorea, et al., 2010)

In general terms, compliance with biosecurity procedures has been found to be incomplete in different studies (Delpont, et al., 2020; Dorea, et al., 2010; Gelaude, et al., 2014; Limbergen, et al., 2017). In one study (Racicot, et al., 2011) used hidden cameras, to asses biosecurity compliance in Quebec, Canada and found 44 different biosecurity fails made by 114 individuals (farm workers and visitors) in the participating poultry farms, over the course of 4 weeks; in average four mistakes were made per visit. The most frequent mistakes were ignoring the delimitation between dirty and clean areas, not changing boots, and not washing hands at the entrance of the barns; these three mistakes were committed in more than 60% of the occasions, regardless of being farm employees or visitors. These are frequent breaches not only of those farms in Quebec but found frequently in many animal production units around the world and have a high probability of causing the entrance and spread of pathogens.

HOW TO CREATE A HIGH BIOSECURITY CULTURE: START NOW!

Creating, applying, and maintaining a biosecurity culture is the most effective way to make sure that compliance of the biosecurity program and procedures is high on the farm. Decreasing, therefore, the probability of entrance and spread of pathogens, reducing the use of antimicrobials, and maintaining animal health. Some actions are recommended in order to achieve a high biosecurity culture:

1.      Name an accountable person

Every operation should have a biosecurity coordinator who is accountable for developing, implementing, and maintaining the biosecurity program.

This important position should be appointed having in mind that certain personality traits may facilitate performance and execution of the labor (Delabbio, 2006; Racicot, et al., 2012; Laanen, et al., 2014; Delpont, et al., 2020) such as responsibility, orientation to action, and being able to handle complexity. Additionally, expertise – years working in the industry y- and orientation to learn are strategic (Racicot, et al., 2012).

2.      Set the environment

When the farm layout is not facilitating biosecurity, compliance is low (Delabbio, 2006), thus the workspace should facilitate biosecurity workflows and at the same time make them hard to ignore (Racicot, et al., 2011).

3.      Allow participation

It is important to mention that not only the management and the biosecurity coordinator are responsible for designing and improving biosecurity procedures. Biosecurity practices must be owned by all the farm workers and should be the social norm.

The annual or biannual revision of biosecurity measures should be done together with the farm staff. This not only serves the purpose of assessing compliance but also allows the personnel to suggest measures addressing existing -often overlooked– gaps, and to be frank about procedures that are not followed and the reasons for it. At the same time, participation increases accountability and responsibility for the biosecurity program.

4.      Train for learning

Don’t take knowledge for granted. Even when a person has experience in farm work and has been working in the industry for several years, their understanding and comprehension around biosecurity may have gaps.

People are more likely to do something when they see evidence of the activity’s benefit. Therefore, if workers are told about the effectiveness of the practices, showing the benefits of biosecurity and analyzing the consequences of non-compliance, they are most likely to follow the procedures (Dewulf, et al., 2018). Knowledge of disease threats and symptoms also improves on-farm biosecurity (Dorea, et al., 2010), thus workers should recognize the first symptoms of disease in animals and act upon them.

Discussion of ‘What if…?’ scenarios to gain an understanding of the key aspects of farm biosecurity should be held on a regular basis. Workers should see examples of the benefits of compliance – and risks of noncompliance – as part of their training.

5.      Lead by example

A high biosecurity culture requires everyone to comply regardless of status.

Personnel practice of biosecurity procedures is not only affected by the availability of resources and training, but also by the position that management takes on biosecurity and the feedback provided. The management and owners must transmit a message of commitment to the farm personnel, owning and following biosecurity practices, procedures and protocols, giving positive and negative feedback on the personnel’s compliance, supplying information on farm performance and relating it with biosecurity compliance and ensuring adequate resources for the practice of biosecurity (Delabbio, 2006).

When necessary, management also should enforce personnel compliance by disciplinary measures, firings, and creating awareness about the consequences of disease incidence. Nevertheless, the recognition of workers’ contribution to animal health performance also has a positive impact on biosecurity compliance (Dorea, et al., 2010).

THE BOTTOM LINE

Biosecurity is necessary for disease prevention in any animal production system. Actions and interventions that prevent the entrance and spread of disease in a production unit have a pay-off as they often lead to performance improvements and lower antimicrobial use.  Maintaining a successful production unit requires a multidisciplinary approach in which biosecurity compliance needs to be taken seriously and also actions to improve in other areas such as management, health, and nutrition.

Do fresh lactation cows need Palmitic acid

The raising demand for butterfat in the US along with higher milk fat price has increased the usage of fat supplements enriched (80 – 98%) with palmitic acid in the dairy industry. Recent studies have shown that feeding palmitic acid to lactating cows increases milk fat production. In postpartum cows; however, feeding supplemental fats may depress feed intake, affect body reserves, and increase the risk of metabolic disorders.

Researchers from Michigan State University evaluated the effects of feeding palmitic acid on production responses and energy partitioning of 52 early-lactation cows. During the fresh period (0 – 24 days in milk) cows were separated in two groups and received a fresh diet either with or without palmitic acid. Posteriorly, during the peak period (25 – 67 days in milk) cows were separated again in two feeding groups and fed a peak diet with or without supplemental palmitic. The fresh diets were higher in protein (17.5 vs. 16.8% in a dry matter basis; DM) and lower in starch (23.5 vs. 25.5% DM) than the peak diets.

The palmitic supplement was added into the diets at 1.5% DM so on average, cows received daily 333 and 450 g of supplement during the fresh and peak period, respectively. Total fatty acid concentrations in the fresh diets without and with palmitic were 3.0 and 4.5%, respectively. Similarly, fatty acid content in the peak diets were 3.5 and 5.1%.

The results of this study were published recently in Journal of Dairy Science (2019), and in summary, the authors de Souza and Lock reported the following findings:

Feeding palmitic acid during the fresh period (0 – 24 days in milk) did not affect intake nor milk yield (22.2 and 47.9 kg/day, respectively). However, cows receiving palmitic produced more energy-corrected-milk (ECM; 56.6 vs. 51.9 kg/day), milk fat (2.29 vs. 2.01 kg/day), and milk protein (1.60 vs. 1.50 kg/day) than cows that did not received the supplemental fatty acid. At the same time, supplemented cows lost more body weigh (2.65 vs. 1.89 kg/day) and body condition score during this period and had higher levels of nonesterified fatty acids (NEFA) in plasma (0.65 vs. 059 mmol/L). Therefore, the greater performance observed in cows fed palmitic may be due to a higher adipose tissue mobilization.

During the peak period (25 – 67 days), regardless of the diet cows received in the fresh period, feeding palmitic increased milk yield (58.0 vs. 54.6 kg/day), ECM production (61.5 vs. 56.9 kg/day), and milk fat yield (2.27 vs. 2.06 kg/day) without affecting DM intake (average: 30 kg/day). Interestingly, the authors observed that feeding palmitic during the peak period increased milk fat yield to a greater extent in cows that did not receive the fat supplement during the fresh period (2.31 vs. 2.23 kg/day).

In addition, cows that received palmitic during the fresh period had lower body weight (675 vs. 695 kg) and lost more body reserves (0.28 vs. 0.18 kg/day) during the peak period than cows that were fed the unsupplemented diet.

Conclusion

In conclusion feeding palmitic acid to fresh cows increases mobilization of body reserves and NEFA concentration in plasma. Therefore, this practice is not recommended during the postpartum period.

By Fernando Díaz

Phytomolecules: Boosting Poultry Performance without Antibiotics

            

Antimicrobial resistance (AMR) is a major threat to global public health. It is largely caused by the overuse of antibiotics in human medicine and agriculture. In intensive poultry production most antibiotics are used as antimicrobial growth promoters and/or used as prophylactic and metaphylactic treatments to healthy animals. Reducing such antibiotic interventions is crucial to lowering the incidence of AMR. However, antibiotic reduction often results in undesirable performance losses. Hence alternative solutions are needed to boost poultry performance. Phytomolecules have antimicrobial, digestive, anti-inflammatory and antioxidant properties, which could make them key to closing the performance gap.

POULTRY PERFORMANCE DEPENDS ON INTESTINAL HEALTH

Poultry performance is to a large extent a function of intestinal health. The intestines process nutrients, electrolytes and water, produce mucin, secrete immunoglobulins and create a barrier against antigens and pathogens.

In addition, it is an important component of the body’s immune defense system. The intestine has to identify pathogens and reject them, but also has to tolerate harmless and beneficial microorganisms. If the intestines do not function properly this can lead to food intolerance, dysbiosis, infections and diseases. All of these are detrimental to feed conversion and therefore also to animal performance.

Antibiotics reduce the number of microorganisms in the intestinal tract. From a performance point of view this has two benefits: first, the number of pathogens is reduced and therefore also the likelihood of diseases; second, bacteria are eliminated as competitors for the available nutrients. However, the overuse of antibiotics not only engenders AMR: antibiotics also eliminate probiotic bacteria, which negatively impacts the digestive tracts’ microflora.

Products to boost poultry performance may be added to their feed or water. They range from pre- and probiotics to medium chain fatty acids and organic acids to plant extracts or phytomolecules. Especially the latter have the potential to substantially reduce the use of antibiotics in poultry farming.

PHYTOMOLECULES ARE PROMISING TOOLS FOR ANTIBIOTIC REDUCTION

Plants produce phytomolecules to fend off pathogens such as moulds, yeasts and bacteria. Their antimicrobial effect is achieved through a variety of complex mechanisms. Terpenoids and phenols, for example, disturb or destroy the pathogens’ cell wall. Other phytomolecules inhibit their growth by influencing their genetic material. Studies on broilers show that certain phytomolecules reduce the adhesion of pathogens such as to the wall of the intestine. Carvacrol and thymol were found to be effective against different species of Salmonella and Clostridium perfringens.

There is even evidence that secondary plant compounds also possess antimicrobial characteristics against antibiotic resistant pathogens. In-vitro trials with cinnamon oil, for example, showed antimicrobial effects against methicillin resistant Staphylococcus aureus, as well as against multiresistant E. coli, Klebsiella pneumoniae and Candida albicans.

Importantly, there are no known cases to date of bacteria developing resistances to phytomolecules. Moreover, phytomolecules increase the production and activity of digestive enzymes, they suppress the metabolism of pro-inflammatory prostaglandins and they act as antioxidants. Their properties thus make them a promising alternative to the non-therapeutic use of antibiotics.

Study design and results

In order to evaluate the effect of phytomolecules on poultry performance, multiple feeding studies were conducted on broilers and laying hens. They were given a phytogenic premix (Activo^®, EW Nutrition GmbH) that contains standardized  amounts of selected phytomolecules.

To achieve thermal stability during the feed processing and a targeted release in the birds’ gastrointestinal tract, the product is microencapsulated. For each , the studies evaluated both the tolerance of the premix and the efficacy of different dosages.

Study I: Evaluation of the dose dependent efficacy and tolerance of Activo^© for broilers
Animals:             400 broilers; age: 1-35 days of age
Feed:                  Basal starter and grower diets
Treatments:
– No supplement (negative control)
– 100 mg of Activo® /kg of feed
– 1.000 mg of Activo® /kg of feed
– 10.000 mg of Activo® /kg of feed
Parameters:       weight gain, feed intake, feed conversion ratio, health status, and blood parameters

Results: The trial group given the diet supplemented with 100 mg/kg Activo^® showed significant improvements in body weight gain during the starter period (+4%) compared to the control group. Additional significant improvements in feed conversion ratio (FCR) in the growing period (+4%) resulted in an overall improvement in FCR of 3%. At a 1.000 mg/kg supplementation, a significant improvement in FCR of 6% was observed over the entire feeding period. Hematological parameters were within the reference range of healthy birds when feeding up to 10,000 Activo®/ kg of feed.

Study II: Evaluation of the dose depending efficacy and tolerance of Activo^© for laying hens

Animals:             200 hens; age: 20 to 43 weeks
Feed:                  basal diet for laying hens
Treatments:
– No supplement (negative control)
– 100 mg of Activo®/ kg of feed
– 250 mg of Activo®/ kg of feed
– 500 mg of Activo®/ kg of feed
– 5.000 mg of Activo®/ kg of feed
Parameters:      weight gain, feed intake, feed conversion ratio, health status, and blood parameters

Results: Inclusion levels from 100 mg/kg of Activo® onwards improved laying performance, egg mass and egg weight and reduced FCR compared to the control group. Results recorded for hematological parameters were within the reference range of healthy birds when feeding up to 5.000 mg Activo®/ kg of feed.

Study III: Evaluation of the dose-dependent effects of Activo^© for coccidiosis vaccinated broilers

Animals:             960 broiler chickens; age: 42 days
Feed:                  Standard starter and finisher feed
Treatments:
– No supplement (negative control)
– 50 g of Activo® /US ton of feed
– 100 g of Activo® /US ton of feed
– 150 g of Activo® /US ton of feed
– 200 g of Activo® /US ton of feed
– 250 g of Activo® /US ton of feed
– Antibiotic growth promoter (AGP)(positive control)
Parameters:      weight gain, feed efficiency
Specific:           In order to represent field conditions, the birds were challenged with used, homogenized litter.

Results: A clear dose response for both body weight gain and feed efficiency was observed (see Figure 1): the more phytogenic premix given, the better the birds’ performance. The group with 200g of Activo® /US ton of feed showed similar performance levels than the positive control group supplemented with AGP.

Figure 1: Dose-dependent effects of for coccidiosis vaccinated broilers

Study IV:  Evaluation of the dose-dependent effects of Activo^© for laying hens

Animals:           40 hens; age: week 20 to 43
Feed:                basal diet for laying hens
Treatments:
– No supplement (negative control)
– 100 mg of Activo®/ kg of feed
– 250 mg of Activo®/ kg of feed
– 500 mg of Activo®/ kg of feed
– 5.000 mg of Activo®/ kg of feed
Parameters:      weight gain, feed intake, egg production, feed conversion ratio, health status
Duration:         168 days of feeding period

Results: The laying hens showed a higher laying rate when fed with a higher concentration of phytomolecules (Figure 2). Similarly improved results were observed for the feed efficiency. The more phytogenic premix added to their diet the better feed efficiency (Figure 3).

Figure 2: Dose-dependent effects of Activo© on laying rate in laying hens

Figure 3: Dose-dependent effects of Activo© on feed efficiency in laying hens

In conclusion, all four studies indicate that the inclusion of phytomolecules in broilers’ and laying hens’ diet improves their performance. Increasing levels of a phytogenic premix (Activo®) significantly increased the production parameters for both groups. These improvements might bring performance in antibiotic-free poultry production on par with previous performance figures achieved with antimicrobial growth promoters.

The studies also showed that microencapsulated phytogenic premixes are safe when used in dose ranges recommended by the suppliers. No negative effects on animal health could be observed even at a 100 fold / 50 fold of the recommended inclusion rate in diets for broiler or laying hens, respectively. Thanks to their positive influence on intestinal health, phytomolecules thus boost poultry performance in a safe and effective way.

By Henning Gerstenkorn

Islamic Events

#Important Islamic Events 

●Completion of Quran =22 yrs, 5 months and 14 days.

●Ghazwa e Badar=2 hijari 

●Ghazwa Uhod =3hijari

●Ghazwa e Khandak =5 hijari 

●Ghazwa e Khyber =7 hijari 

●Ghazwa e hunain =8 hijari

● Ghazwa e motta =8 hijari

●Conquest of makkhah=8 hijari 

Jung e yamama =8 hijari 

●Ghazwa e Tabook =9 hijari 

●Bait- ul -maqdas changed to Bait Ullah Shareef=2 hijari 

●Azan become compulsory =2 hijari 

●zakat =2 hijari 

●Parda/nqab ka hukam=4 hijari 

●Bait e Rizwan/Bait e shajar =6 hijari 

●Sulah hudaibia =6 hijari 

●sharab was prohibited =6 hijari 

●Hajj ki faziat =9 hijari 

●Khutba hijjat-ul-wida =10 hijari 

●Interest was prohibited =10 hijari 

●1st hijarat e Habsha=5 nabwi 

●2nd hijarat e Habsha =7 nabwi 

●Maqat,at e Quraish /shab e abi talib=7 nabwi to 10 nabwi 

●Aa, am al hazan year =10 nabwi 

●Namaz ki farziat=11 nabwi 

●waqi,a-e-ma,raj =11 nabwi 

●Namaz e janaza ki farziat =2 hijari 

●Roza ki farziat =13 nabwi

Tayamum ka hukam =4 hijari....