Ever-rising disease trends and devastating disease outbreaks raised a definite awareness about the concept of biosecurity and its importance. Biosecurity refers to the designed measures and methods to reduce the spread of pathogens between the farms. The stringent biosecurity program ensures a diseasefree environment for better productivity and profitability. High pathogen load results in increased mortality and impacts the performance leading to significant losses. Proper biosecurity practices in broiler production reduce the introduction of pathogens1. However, lower levels of biosecurity lead to a higher prevalence of disease2. Drinking water is a vital source of infection, and good quality water is essential for the optimum health of birds. Increased frequency of water sanitation is significantly associated with good flock performance3. Implementation of suitable biosecurity measures require expenses and hence maintain the cost according to risk. Yet, according to studies, the most stringent levels of biosecurity cost is justified at lower chances of the disease outbreak4.
At the grass-root level, farmers have failed to understand the correct approach, vast horizon, and the depth of biosecurity. The impact of the biosecurity program on productivity and profits is not well understood. Improper understanding of biosecurity principles and tools results in conventional practices and inappropriate biosecurity measures. This approach leads to a breach in biosecurity resulting in loss of profitability and an increase in losses. Hence, it’s needed to understand the basic principles of biosecurity and differentiate between available options to make the correct choice.
Levels of Biosecurity
Biosecurity levels depend on the farm selection (conceptual biosecurity), farm construction (structural biosecurity), and practices to prevent disease outbreaks (operational biosecurity)5.
Biosecurity programs depend on two fundamental principles, viz. Bio-exclusion (preventing the pathogen introduction), and Bio-confinement (preventing further pathogen spread)5. However, popular practices and beliefs are based mostly on operational biosecurity and bio-confinement.
Lack of knowledge on diseasecausing agents, differentiating between different classes, and usage of disinfectants made the farmers opt for incorrect choices that lead to undesirable outcomes. It is common to find unsafe and irritant sanitizer usage in drinking water and narrowspectrum disinfectant as a terminal disinfectant. Thus, it is necessary to understand the properties of disinfectants before using it for biosecurity purposes.
Disinfectants are substances used to control, prevent, or destroy harmful microorganisms on inanimate objects and surfaces. Sanitizers do not eliminate all microorganisms but reduce the microbial levels that are considered safe from health point6. In order to select the correct sanitizer and disinfectant, it is important to understand the properties of an ideal disinfectant, factors affecting disinfectant efficacy, and various classes of disinfectants based on chemical nature, mode of action, antimicrobial spectrum, and usage.
Properties of Ideal Disinfectant6,7
- High speed of disinfection/ low contact time: achieve complete disinfection in a limited window of time.
- Broad antimicrobial spectrum: eliminate all potential pathogens, as different microbes have different innate resistance against disinfectants. For example, non-enveloped viruses are more resistant than enveloped viruses, and fewer disinfectant groups work on them.
- Bird/ personnel health and safety: important parameter as disinfectants in high concentration can be corrosive, irritant and carcinogenic, and harms the skin and mucous membranes upon contact, ingestion, and inhalation.
- Material compatibility: disinfectants are known to deteriorate or stain material in high concentration, for example, strong acids, strong alkali, and iodine.
- Solubility and stability: good penetration and efficient disinfection. Example- unstabilized hydrogen peroxide or chlorine may lose its efficacy.
- Cleaning ability: for better penetration of disinfectant and its efficacy. Example- quaternary ammonium compounds (QAC), a better cleaning agent.
- Cost efficiency and availability: for economical use of a disinfectant.
Factors Affecting Disinfectant Efficacy7
- Type of organism and its innate resistance: Spore forms are more resistant than vegetative bacteria, and non-enveloped viruses are more resistant than the enveloped virus
- Microbial load/ degree of contamination: As the disinfectants do log reduction of microbes, a higher degree of contamination may result in a higher final load.
- Disinfectant concentration, potency, chemical nature, antimicrobial spectrum, mode of action, and contact time affect the disinfectant efficacy.
- A load of proteinaceous, organic, and inorganic matter on the disinfection surface is vital, as different disinfectants have variable disinfectant efficiency in the presence of organic amount. For example, phenols have good efficacy in the presence of organic matter.
- Physical and chemical factors like temperature, pH, hardness, relative humidity affect disinfectant efficacy. For example, chlorine disinfectants work efficiently in acidic pH.
Classification of Common Poultry Disinfectants based on Chemical Nature6
- Quaternary ammonium compounds: Benzalkonium chloride (BKC)
- Aldehydes: Formaldehyde and Glutaraldehyde
- Phenols: Cresylic acid and Orthophenyl phenol
- Chlorine compounds: NADCC (Sodium dichloroisocyanurate)
- Bromine compounds: BCDMH (Bromo-chloro-dimethyl-hydantoin)
- Iodine compounds: Iodine and Hypoiodous acid
- Oxidizing agents: KMPS (Potassium monopersulphate) triple salt, Hydrogen peroxide
- Alkali: Sodium hydroxide, Ammonium hydroxide
- Acids: Hydrochloric acid, Acetic acid, Citric acid
Classification based on usage in Poultry
- Water acidifier: Various organic and inorganic acids as water acidifier and weak sanitizer.
- Water sanitizer: Halogen compounds, QAC, Hydrogen peroxide as water sanitizers.
- Continuous disinfectant: Non-irritant, relatively safe for spray in the presence of birds, for example, KMPS, QAC, and low concentration glutaraldehyde.
- Terminal disinfectant: High-level disinfectants for the spray in an empty shed (Aldehyde, Phenol)
Classification of Common Poultry Disinfectants based on Disinfection Level6,7
Disinfectants are classified to be low, intermediate, and high-level disinfectants based on their ability to destroy various resistant microorganisms.
- QAC compounds have good cleaning properties and safety, but a weak antimicrobial spectrum. QAC function best as a sanitizer: for example, AcidLAC™ W contains DDAC (didecyl dimethyl ammonium chloride) in combination with organic acids and widely used as a water sanitizer. Various generations of QAC evolved to improve its efficacy as a disinfectant. Disinfectants like tributyltin oxide (TBTO- antifungal agent) and glutaraldehyde can enhance the efficiency of QAC. Keciddal™ T Plus is an example of such fortified formulation that provides a broad antimicrobial spectrum with high safety for spray in the presence of birds.
- KMPS triple salts are best suited as continuous disinfectants to spray in the presence of birds or as water sanitizer. They have a broad antimicrobial spectrum but moderate efficacy with organic matter. For example, Trysil™ is KMPS triple salt in combination with NADCC, providing a broad antimicrobial spectrum and high safety.
- Formaldehyde in high concentrations is suitable only as a terminal disinfectant (in the absence of birds) due to highly irritant nature and low relative safety.
- Glutaraldehyde has a broad antimicrobial spectrum and moderate efficacy in the presence of organic matter. They have relatively better safety, less corrosiveness, less irritant action in comparison to formaldehyde. Glutaraldehyde uses in higher concentrations as high-level terminal disinfectants or moderate concentration in combination with other disinfectants like QAC for spray in the presence of birds.
- Chlorine compounds have limited activity in the presence of organic matter, and their efficacy is pH-dependent. At high concentrations, they are corrosive, irritant, and leave the residue of unwanted compounds. Thus, they are best suited to use as water sanitizer. While using chlorine compounds as a sanitizer, it is vital to manage the water pH in an optimum range of 6-7 for the best results. Chlorine compounds should never come in direct contact with concentrated acids before dilution. Chlorine compounds such as NADCC can be used in combination with bromine compounds such as BCDMH to achieve a broad antimicrobial spectrum and efficacy in a wide range of pH. GLANTAB™ is an example of such fortified compounds and readily used as a water sanitizer in poultry.
- Iodine compounds use as antiseptic is well known, but in disinfectant concentrations, it is irritant, corrosive, and stain the surfaces. Thus, their use is best suited as a water sanitizer.
- Organic acids help to attain desirable water pH and are best for gut health. Organic acids in correct combination and concentration can reduce the load of poultry pathogens and slow down their multiplication. AcidLAC™ Azure is a unique blend of potentiated organic acids which are highly effective even in water with high hardness.
- Hydrogen peroxide has a broad antimicrobial spectrum, but their penetration ability is low leading to restricted use as surface disinfection. Hydrogen peroxide has poor stability after dilution unless modified, widely used alone, or in combination with strong alkalis like peracetic acid for biofilm removal from water pipelines and water tank cleaning in the absence of birds’.
- Phenols have moderate to a high level of disinfection depending upon composition, high efficacy in the presence of organic matter with irritant action, and suited for empty shed disinfection, vehicle wash, and foot bath. Kem V 260® is a highly effective phenolic disinfectant with broad-spectrum activity against bacteria, viruses, fungi, and coccidian oocyst.
The concept of biosecurity is vital to understand andimplement the practices,so as to get the recommended performances. Similarly, understanding various disinfectants, their benefits, can help to choose the correct disinfectant for that purpose. This knowledge will lead to better decisions, low losses, and high profitability.
by Dr. Praveen K Singh, Dr. Venket Shelke and Dr. Partha Das, Kemin Industries South Asia Pvt. Ltd.