Factors to be considered for Improvement of Gut Health to achieve Antibiotic Free Poultry Production
The antibiotic free poultry production has become a major focus in the poultry industry, since the consumer preferences for antibiotic free products have increased. The theoretical hazard to human public health related to the use of antibiotic growth promoter is the transfer of resistant microorganisms from animals to humans largely via the food chain. Thereafter they might either transfer their resistance to organisms that affect human or cause infection themselves that may be difficult or impossible to treat (Philips, 1999). The use of antibiotics in the poultry production is mainly to improve the gut health of the birds and control of diseases at sub-therapeutic and therapeutic levels, respectively. But, the usage at any dose may lead to antibiotic residues in the egg and meat of the birds. This will lead to development of antibiotic resistant bacteria in the humans consuming such products. Hence, antibiotic free poultry production has gain more importance among consumers.
The antibiotic free poultry production is mostly focused on the reduction of inclusion levels in the feed and water consumed by the birds. But, the poultry farmers mostly fail to focus on the factors that contaminate the gut of the birds that cause alterations in the gut health of them. The contamination may also cause diseases in these birds which often needs antibiotic treatment for recovery. The contamination may be through feed, water, ventilation, manure, vehicles and visitors entering the farm, wild birds, pests and vermin. Good barn sanitation, pest control, biosecurity practices, and litter or manure management are necessary to reduce pathogen load and exposure and minimize the need for antimicrobial therapy (Ferket, 2004).
The risks of contamination posed by these factors can be reduced through improvement of the following factors at the farm level-
Procurement of good quality of the chicks
Strict biosecurity measures
Monitoring of raw material quality
Improvement of feed hygiene
Improvement of feed digestibility
Improvement of water hygiene
Procurement of good quality chicks:
The most important consideration for an antibiotic free poultry production system is the procurement of the good quality chicks. If the chicks are contaminated in the hatchery or at the breeder farm levels, the bacteria, such as Salmonella and Mycoplasma, could be already present in the chicks. If the quality of the chick arriving on to the farm is compromised, antibiotics will be required to ensure the chicks survive. Hence, the good quality chicks needs to be procured for a better quality of the final products.
Strict biosecurity measures:
Biosecurity is a major factor which helps in the reduced usage of antibiotics for the birds. It is to be maintained at breeder farm level, hatchery level and on farm (production) levels. Improvement of biosecurity at the breeder farm and hatchery may result in the less infection in the chicks produced, leaving less number of bacteria in the chick gut. This can be improved by supplementing the chicks with probiotics on the first days of arrival at the production house, which improve the gut health of the chicks. On-farm strict biosecurity standards lead to reduced infection of the birds with commensal bacteria. Hence, more importance needs to be given to the biosecurity at the on-farm level.
Monitoring of raw material quality:
The raw materials quality is another important factor for good gut health. Among the raw material quality attributes, the presence of mycotoxins and anti-nutritional factors needs to be monitored closely. These two factors can modify the gut integrity through various mechanisms. Hence, close monitoring of the raw material quality is very important for the maintenance of gut health.
The mycotoxins are certain fungal metabolites which contaminate the feed raw materials pre and post-harvest from the fields. They are present at different levels in different raw materials depending on the environmental and management factors. They cause disturbances of metabolic, physiological and immunological functions in the body of the birds. Regular testing of the feed raw materials for the mycotoxins could eliminate the infected raw materials and take safety precautions, if infected feed are unknowingly included in the feed. Also, toxin binders for the already present toxins, mold inhibitors for preventing the growth of molds, etc. could be done to prevent the mycotoxin problems in the flock.
Anti-nutritional factors are the factors, which are present in the feed, affect the digestion and absorption of the other nutrients in the birds. They may be deactivated through various processes, such as heat treatment for trypsin inhibitors in the soybean meal, etc. When the processes of deactivation of antinutritional factors are not proper, they may be present in the feed and cause serious alterations in the digestibility of the feed in the birds. These anti-nutritional factors can be avoided through close quality control of raw materials, and by using specific enzymes to neutralise them, so that, it will consequently allow for the reduction of antibiotic use in the feed.
Improvement of feed hygiene:
Some of the feed ingredients may be contaminated with bacteria such as Salmonella, in them before arriving at the feed mill. At the mill levels, storage and handling may also be sometimes compromised which result in the contamination of the raw materials. Even though, the practices like heat treatment through conditioning and pelleting could improve the feed hygiene, the storage and handling of the finished feeds could cause contamination of the same. The inclusion of acidifiers in the feed could lead to improvement in the feed hygiene.
Improvement of feed digestibility:
The digestibility of the feed is another factor which causes the problems in the integrity of the gut health of the birds. Poorly digested feed materials causes more nutrients to be available for the hindgut bacteria, which results in the flare up of the hindgut bacteria including harmful bacteria such as, Clostridium perferingens causing necrotic enteritis (Kaldhusdal and Skjerve, 1996). Such conditions increase the use of antibiotics for the recovery of the affected birds. The inclusion of enzymes, organic acids, essential oils, phytogenic products, etc. can improve the digestibility of the feed. More digestion by the birds means fewer nutrients available to the bacteria in the hind gut, resulting in a natural modulation of the bacterial populations.
Improvement of water hygiene:
The water is an important nutrient in the birds’ diet. Birds consume water nearly two to three times that of the feed, which increases still more during summer in tropical countries. Mostly water is obtained from the wells and bore wells in our country, which may be contaminated with E. coli and other bacteria. The contaminated water becomes a vector for the pathogenic bacteria in the flock. So, the water provided to the birds needs to be decontaminated before they are fed to the birds. The water may become contaminated through improper maintenance of the water tank and pipe lines in the house. Thorough cleaning of the tank and pipelines at regular intervals can reduce the risk of contamination at the house level. Water must be clean and drinkers must be properly maintained to minimize spillage and prevent a bloom of pathogens in the litter and environment of the animals (Ferket, 2004). The processes such as chlorination, liquid acidifiers, UV treatment, etc. may result in the reduction in the pathogenic bacterial load of the water, ultimately resulting in the reduction of antibiotic use.
The inclusion of the antibiotics in the feed of the birds can be avoided by the use of various other gut health promoters such as, enzymes, acidifiers and organic acids, phytogenic feed additives, prebiotics, probiotics, etc. These supplements act internally in the gut of the birds. The improvement, monitoring and maintenance of the above discussed factors, which act external to the birds, also compliment the same concept. Hence, combination of the various external factors and the antibiotic free feed through supplementation of gut health promoters could be the best alternative for the antibiotic free poultry production systems.
ICAR-Central Avian Research Institute, Izatnagar, UP.
Ferket, R. Peter, 2004. Alternatives to antibiotics in poultry production: responses, practical experience and recommendations. Proceedings of Alltech’s Twentieth Annual Symposium. pp. 57-68.
Phillips, I. 1999. Assessing the evidence that antibiotic growth promoters influence human infections. J. Hospital Infections. 43: 173-178.
Kaldhusdal, M. and Skjerve, E. 1996. Association between cereal contents in the diet and incidence of necrotic enteritis in broiler chickens in Norway. Prev. Vet. Med. 28: 1-16.