Antimicrobial products used in animal food production helps to treat infectious causes, and as well as for growth of promotional purposes. It increases the exposure of bacteria to antibiotics and increases the chances of developing antimicrobial resistance over time. Resistance to antimicrobials is a serious global health issue. European Union banned the usage of antibiotics as growth promoters from 2006, and a few Asian countries followed such a ban. A great awareness started building up amongst the public on this front. So, the food animal producers in countries like the US voluntarily started withdrawing the usage of Antibiotic Growth Promoters (AGPs) while using manage mental measures and alternative products to AGPs.
The objectives of antibiotic-free (ABF) chicken production ensure the consumers that the chicken is free from antibiotic residues & antibiotic resistance and addresses chicken & human health awareness. The measures that are recommended by Kemin in ABF chicken production include – hatchery hygiene, biosecurity, cleaning and disinfection of farms, sanitized water, feed mill hygiene, and nutritional measures that include the usage of alternatives to AGPs.
Nutritional Measures to Reduce Anti-microbial Resistance
There are several principles and school of thoughts that can control anti-microbial resistance (AMR) in chicken. Some of the important areas to consider under nutritional perspective are as below.
A) Ensure a stable and healthy gut ecosystem in chicken
B) Effective immune status of birds
C) Reduction of systemic infections or challenges
D) Control of oxidative status in birds physiological system
E) Maintain a well-balanced neuroendocrine system
F) Optimal digestion and absorption in gut
G) Secure strong intestinal barrier to reduce bacterial challenges
Maintaining all the above factors will support ABF chicken production and eliminate AMR development without ill effects on animal productivity.
Nutritional Programs to Successfully Address AMR in Chicken
- Raw material Quality Control:
Manufacturing poultry feed without antibiotics may harness several diseases, and this may aggravate if we compromise with safety and quality of raw materials in terms of pathogen load and nutrient levels. The raw materials presumably should be of vegetable origin to avoid unnecessary risk due to bacterial contamination, like E. coli, Salmonella, Clostridium, etc. Mold and toxin levels of microbes, mold & pesticides should be below standard or within accepted levels. Regular raw material checking for rodent or insect infestation as well as physical appearance eventually control its safety and nutrient levels, and it should comply with standard permissible limits. Adulteration level and anti-nutritional factors of raw materials should be within the standard limits. Itavoids large variation in nutrient levels and ensures the health safety of birds. Rancidity parameters of raw materials like oils, rice polish, etc., should be regularly assessed since rancidity has a direct correlation with nutrient loss and gut health. All raw materials should be routinely screened to check the nutrient variation, and procurement should be followed for raw materials with minimum variation. Proper storage of raw materials and finished feed avoids higher nutrient loss, rancidity, pathogen, insect, mold, or mycotoxin contamination. The quality inspection orthe quality audit must be routinely followed for all raw materials and finished feed to comply with standard guidelines.
- Raw Material Selection:
Gut viscosity and digesta flow are two important criteria that regulate the development of the intestine, gut motility, rate of nutrient absorption as well as maintain healthy microbiota in the intestine. High digesta viscosity may have a negative role on the above physiological conditions. Addition of a high level of non-starch polysaccharides (NSPs’) to chicken diets through higher inclusion of raw materials rich in NSP, i.e., wheat, rye, etc., leads to increased gut viscosity and reduced nutrient absorption, particularly saturated fats. Hence raw materials that hold good for optimum gut viscosity will ensure better digestion and minimum nutrient wastage. Raw materials with a high level of soluble NSPs’ and non-degradable substrates should have restricted usage in feed formulations. Also, the use of broad spectrum NSPase enzyme and biosurfactants have been shown to positively affect gut viscosity and improve digestion & nutrient absorption. Certain raw materials with a high level of nutrient variation like dried distillers grains with solubles (DDGS), rice gluten, wheat, deoiled cakes (DOC) should be carefully used by considering more accurate nutrient values.
- Ensure Healthy Gut Ecosystem and Prevent Intestinal Inflammation:
Birds’ gut as well as enteric system subjects to several challenges and infections once the birds are under stress. Factors such as stress, pathogen, feed contaminants can loosen the intercellular tight junctions of the intestine leading to a syndrome called leaky gut. A leaky gut facilitates the bacterial pathogens & toxins to pass in between the epithelial cells leading to cellular damage and intestinal inflammation. Providing broad-spectrum probiotics warrant better gut integrity and a healthy gut ecosystem. Gut acidifiers will maintain the required gut pH and enhanced enzymatic secretions. Vitamin C and organic chromium ensures better glucose metabolism, reduce stress, and oxidative damage to the tissues. Butyrates increase the absorptive surface area of enterocytes and enhances nutrient absorption. Prebiotics effectively stimulate the gut ecosystem, gut health, and immune status of birds.
- Nutrient Level Optimization of Diets:
Birds need sufficient nutrient levels to support maintenance and production demands and fulfill requirements during stress conditions and immunosuppression. Formulations need to be considered based on the digestible amino acids and ideal protein concept, rather than crude protein to reduce protein wastage, litter borne disease and body heat. Excess amino acids and protein should be avoided to ensure better nutrient balance and uptake. Provision of buffer nutrients like metabolizable energy (ME), macro and micronutrients, and salts may effectively reduce stress or immunosuppression. A good quality fat level increases during summer stress to reduce body heat increment and benefit the extra calorific value of oil. Consider broad-spectrum enzyme application covering maximum substrate (multi NSPase, carbohydrase, multiprotease) to ensure better digestion, absorption, and bird performance.
- Maintain Superior Immune Statusof Birds:
Intensive farming conditions laid the importance of maintaining the strong immunity in birds throughout the life cycle. Optimal nutrition plays a pivotal role in minimizing the incidence of disease by enhancing immunity. Essential amino acids like arginine, threonine, valine, and glutamine are known to have a role in immunomodulation. Ensure that these requirements are fulfilled conditionally. Vitamin C, Vitamin E, Vitamin D3 aid in developing immunity. Also, among the trace minerals, zinc, manganese, and selenium have a positive effect on immunomodulation, wherein additional supplementation of 10 to 15 % might be crucial. Better electrolyte balance in the body is important for better osmotic regulation and transport of essential nutrients, which eventually support a strong immune system and optimum feed intake. Additives like the combination of organic chromium and vitamin C and beta-glucans help in facilitating better immunity levels in birds.
- Feed Plant Process and Quality Control:
Maintaining standard guidelines for feed processing is vital to maintain uniform quality feed and bird productivity. Factors like proper grinding, mixing, steam conditioning, starch gelatinization, pelleting, optimum pellet durability index (PDI), and particle size, etc., play a pivotal role in ensuring quality feed and superior bird performance. Optimum particle size distribution in feed has a positive effect on the gizzard function, nutrient absorption, sustained digesta flow, and better bird productivity.
Nutritional intervention plays a critical role in allowing farmers and veterinarians to reduce the usage of AGPs. Alternative products to AGPs are employed primarily for promoting growth and infection prevention, with fewer options available for treatment. In addition to the nutritional measures, we need to focus on management strategies including biosecurity, water management, vaccination for prevailing diseases, and regular disinfection. Further, complement the effects by reducing the risk of pathogens being introduced and spreading in the herd or flock.
References will be available on request.
by Dr Partha Das, Head-Technical, Kemin Industries South Asia Pvt. Ltd.