Doxycycline is a broad-spectrum antibiotic that can be used to treat a variety of bacterial infections in both humans and animals. It works by inhibiting the synthesis of essential proteins, which prevents bacteria from growing.
In poultry, the use of doxycycline has been approved by the US Food and Drug Administration (FDA) since 1996 as an alternative to coccidiosis control. The drug is administered in feed at a rate of 0.1% to 0.5%.
Coccidiosis is caused by Eimeria parasites, which can cause severe damage to the intestine of birds and death if left untreated. Doxycycline prevents coccidiosis by eliminating these parasites from your bird’s intestinal tract so they cannot reproduce or spread throughout your flock.
Doxycycline is an antibiotic used to treat respiratory pathogens in poultry. There are several antibiotics that treat Mycoplasma species, and doxycycline is a semisynthetic derivative of tetracycline. This agent has a high volume of distribution and good oral absorption. However, the safety profile of doxycycline in poultry is not well understood.
The pharmacokinetics of Doxycycline was studied in 20 broiler chickens. The drug rapidly distributed in the chicken body following i.v. or oral administration. Its plasma concentration was highest after the first two doses, and its elimination was minimal. The pharmacokinetic profile of Doxycycline in poultry was similar to that of humans. In humans, the drug was rapidly distributed and eliminated from the body, but in poultry, the drug reached its Cmax at about ten hours after oral administration.
To determine the absorption profile of Doxycycline in poultry, blood samples were obtained from the wing vein and centrifuged at 3000 rpm for 10 minutes. The serum samples were used to estimate the doxycycline concentration. Samples were stored at -20°C until analysis. The assay was performed within a week of collection. Amount of the drug to be given to poultry was determined by the area under the serum concentration curve.
Plasma samples were collected at 24-h intervals during the dosing period and immediately prior to each oral administration. Serum concentrations were measured using high-performance liquid chromatography and noncompartmental analysis, and the peak serum concentration was calculated. Doxycycline was absorbed by the upper portion of the digestive tract and milk had little effect on its absorption. The drug has a strong affinity for lung and renal tissues. Its serum half-life is 16 to 22 hours.
The pharmacokinetics of Doxycycline in chickens were studied using a single oral and intravenous dose. Plasma concentrations were determined using high-performance liquid chromatography. The two-compartment model was used to calculate pharmacokinetic parameters such as elimination half-life, maximum concentration (Cmax), and mean residence time. These parameters were comparable to that observed in poultry.
In a previous study, the pharmacokinetics of doxycycline in turkeys and chickens was compared. Serum concentrations were determined by HPLC. Pharmacokinetic parameters were calculated using compartmental analysis. The results of the study showed that doxycycline is not significantly different after oral and intravenous administration in these species. However, the results from the study did show some interesting results.
The pharmacokinetics of Doxycycline in turkeys and broilers were reported in the Proceedings of the sixth European Association of Veterinarians and Poultry Technologists’ Congress in Edinburgh, Scotland. Other studies have also reported on the depletion of the drug in poultry eggs and meat. The safety of Doxycycline in poultry has been questioned because it is not approved for human consumption.
Ostriches showed a higher peak concentration of doxycycline than other species. The doxycycline plasma concentrations were 1.6 ug/ml and 1.5 ug/kg. However, the second-dose concentration was much higher than that of turkeys and goats. These results indicate that doxycycline is rapidly distributed in poultry. In goats and sheep, it is absorbed into the bloodstream through the gastrointestinal tract, where it is quickly cleared.
In poultry farming, it is difficult to produce food free of antibacterial agents, such as doxycycline, as most are administered in water. Antibiotic residues in food may increase unexpectedly, due to unintentional administration. To address this issue, the present study examined whether constant exposure to the antibacterial agent enrofloxacin affects the withdrawal time of therapeutic doxycycline. LC-MS/MS was used to measure the concentration of antibacterial agents and doxycycline in poultry feed.
Withdrawal time for Doxycycline in poultry has been calculated by considering the withdrawal time after intramuscular administration of the drug. The withdrawal period was also calculated for florfenicol (FF), its metabolite florfenicol-amine (FFA) and the product ‘florfenicol’. Because of this, the withdrawal time is much longer than the normal period.
During the first 24-hr interval, additional samples were collected. Prior to each oral administration, a sample was collected for noncompartmental analysis. The doxycycline concentrations were compared in the first and last 24 hours. Doxycycline withdrawal time in poultry is about three days. In poultry, the dose of doxycycline should not exceed 50 mg/kg of body weight. The dose should be diluted to therapeutic concentrations before administration.
Heart and gizzard concentrations
Doxycycline, a commonly used antibiotic, has low levels in the heart and gizzard of chickens. It is used in poultry feed to treat respiratory and gastrointestinal diseases, and is not harmful to human beings. There is a 7-day withdrawal period for meat chickens after doxycycline treatment. The concentration of doxycycline in the heart and gizzard of poultry is lower than that in chicken eggs and hens.
Doxycycline is a broad-spectrum antibiotic, inhibiting protein synthesis. Other tetracycline agents are Chlamydia and Oxytetracycline. These drugs are effective against both gram-positive and gram-negative bacteria. Some anaerobes, Chlamydia, and several rickettsiae are also susceptible to tetracycline treatment.
Doxycycline reduced E. coli infections in chickens. However, the concentrations of E. coli in broiler chickens were not significantly affected by doxycycline treatment. Probiotics were added to supplement the diet of chickens treated with doxycycline. Probiotic supplements improved gut microbial balance. Olnood et al. reported a gradual increase in pH concentration from the proximal to the distal GI tracts in birds treated with doxycycline. Further, the probiotic supplemented birds had significantly lower pH levels and fewer P. multocida and enterobacteria in the ileum.
Both coccidiostats and Doxycycline have some advantages and disadvantages. Coccidiosis is a contagious amoebic disease that affects livestock and poultry living in warm environments. While both coccidiostats and Doxycycline are used to control the disease, residues of both can be harmful to humans. To avoid this potential problem, it is recommended to use alternative methods of control.
These two drugs are highly effective in controlling coccidiosis in poultry. They have different pharmacological effects and are classified by their chemical structure. They are also categorized by their pharmacokinetic profiles. The drug residues produced by coccidiostats in poultry must be lower than the permissible limit and they must be removed within a specified withdrawal period. Both coccidiostats and Doxycycline should be used only during the last phase of the disease in poultry.
Antibiotics used to treat coccidiosis in poultry must meet stringent standards. Veterinary drugs such as Doxycycline and Coccidiostats are medically important antibiotics. These drugs must be used for a specific period of time, as determined by FDA guidelines. The withdrawal time is also FDA-approved. Veterinary feed directive drugs must be given to a specific number of chickens to reduce the risk of overuse in poultry.
Although coccidiosis is not an immediate threat to poultry, it can cause a weakened growth and wet manure. In some cases, birds may become ill without the use of coccidiostats. The use of these drugs in poultry is increasingly widespread as it protects birds’ health and welfare. However, synthetic coccidiostats may build full resistance to the drugs and must be changed regularly to ensure effective control.
The FDA defines ionophores as antibiotics that prevent coccidiosis, a common intestinal disease of poultry. This disease increases the risk of an outbreak of Clostridium perfringens, a serious bacterial infection that can cause necrotic enteritis and, in severe cases, death. In addition to preventing coccidiosis, ionophores also control some types of bacteria.
Bacitracin and ionophores inhibit resistance transfer in a concentration range of 50-500 ppm for gram-negative isolates. In poultry, resistance transfer was boosted by 75% whereas it was only 33% in swine feces. The results from both The Netherlands and Belgium were similar, suggesting that the decrease in susceptibility was not due to the lasixocid or monensin.
Tetracyclines are antimicrobials and growth promoters for livestock. They inhibit protein synthesis and can interfere with RNA and DNA synthesis. These antibiotics are also effective against several anaerobes, Chlamydia and Clostridium, as well as some protozoa. However, they can also inhibit antidiuretic hormones. The use of these antibiotics in poultry is not recommended for human consumption.
The American Veterinary Medical Association has endorsed the guidelines from the American Association of Avian Pathologists. These guidelines are based on the Principles of Judicious Therapeutic Use of Antimicrobials for Poultry. These guidelines are currently a working document and may change over time. You should consult with your veterinarian for any questions or concerns regarding the use of antimicrobials in poultry. The FDA’s guidance on antibiotics in poultry explains the importance of veterinary oversight of these antibiotics.