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The antibacterial mechanism and clinical application of chlortetracycline premix!

View: 4 Author: Site Editor Publish Time: 2023-11-14 Origin: site

The antibacterial mechanism and clinical application of chlortetracycline premix!

Chlortetracycline (CTC) is a microbial secondary metabolite isolated from the culture fluid of Streptomyces aureus by Duggar in 1948. It belongs to the tetracycline antibiotics and is used in livestock and poultry production at home and abroad at a preventive dose (50 -75mg/kg) is used in feed to promote the growth of livestock and poultry. At present, the proportion of chlortetracycline used as health care medicine and disease prevention medicine in the breeding industry is increasing.

Chlortetracycline premixis mainly used for: treatment of diarrhea in weaned piglets; treatment of pig asthma, proliferative enteritis, etc. (including sow Leptospira, Chlamydia, Rickettsia, etc.). 

Prior to this, chlortetracycline was sold to feed companies as a pharmaceutical feed additive to promote growth and prevent epidemic diseases in animals. From now on, it must be used as a treatment and therapeutic preventive drug at the breeding site according to the prescription of a veterinarian. 

The method of use is to mix it in the feed for animal consumption.


1. This product is a tetracycline antibiotic, but its antibacterial effect is significantly stronger than that of tetracycline and oxytetracycline. 

2. Through a unique processing technology, this product overcomes the shortcomings of incomplete oral absorption and low bioavailability of the raw material chlortetracycline hydrochloride, making this product fully absorbed after oral administration, with high blood concentration, reducing the overall dosage and body's Drug residue.

3. This product is sensitive to Rickettsia, Mycoplasma, Chlamydia, Atypical Mycobacterium, and Spirochaete. Its mechanism of action is that the drug can specifically bind to the A position of the 30S subunit of the bacterial ribosome, inhibiting the growth of the peptide chain and affecting bacterial protein synthesis.

Antibacterial mechanism

1. Regulation of microbial genes by chlortetracycline 
Chlortetracycline mainly binds to the A position of the 30S small subunit of microorganisms, thereby interfering with the binding of the aminoacyl tRNA to the 30S small subunit, preventing the aminoacyl tRNA from entering the acceptor site on the mRNA, and inhibiting the elongation of the peptide chain during protein synthesis; 
Chlortetracycline can also prevent the release of synthesized protein peptide chains; tetracyclines can also cause changes in cell membrane permeability, causing intracellular nucleotides and other important components to leak out, thereby inhibiting bacterial growth and reproduction.

2. Regulation of intestinal microbial colonies by chlortetracycline
A large number of domestic and foreign studies have shown that adding chlortetracycline can inhibit E. coli in the intestine, delay the colonization process of intestinal microorganisms, and reduce blood ammonia concentration. 

Research shows that 50 mg/kg or 150 mg/kg chlortetracycline has a significant impact on the respiration intensity of feed (P < 0.05). chlortetracycline has a significant inhibitory effect on microorganisms in the feed, and gradually The inhibitory effect increases as the content increases.

Functional use

This product is a broad-spectrum antibacterial drug that is sensitive to Gram-positive bacteria, Gram-negative bacteria, Rickettsia, Mycoplasma, Chlamydia, atypical mycobacteria, and spirochetes. It can prevent and treat porcine epierythrozoonosis, pig Pneumonia, asthma, pleuropneumonia, metritis, mastitis and yellow and white diarrhea. Experiments have shown that it also has an alleviating effect on weaning stress in piglets.

Regulation of nutrients by chlortetracycline

  • Chlortetracycline can improve the absorption and utilization of protein and trace elements, increase the utilization rate of Ca and P, and promote the digestion and absorption of mineral elements. 
  • Increased body weight gain of broilers, while reducing blood uric acid and ammonia concentrations, indicating that chlortetracycline has the effect of promoting nitrogen deposition; 
  • There is a significant interaction between chlortetracycline, lysine and methionine. When chlortetracycline is added at 150 mg/kg and the levels of lysine and methionine are 1.3% and 1.6% respectively, the growth performance of broilers is optimal. , has the effect of increasing the requirements of lysine and methionine for broilers.

Application of chlortetracycline in pig production

  • Used in sow production to significantly improve reproductive performance. 

  • Adding mycogenin + chlortetracycline to the diet of sows for 7 days before and after delivery significantly reduces the incidence of agalactia syndrome (MMA), significantly increases the estrus breeding rate within 7 days after weaning, and increases the number of live piglets per litter. 0.8 heads: 

  • Adding chlortetracycline to 120 empty-pregnant sows weaned at 21 to 25 days for breeding, the conception rate during estrus increased by 4.1%, the farrowing rate increased by 5.8%, the number of live piglets in the litter increased by 0.25, and one sow can make more profits per year. More than 100 yuan.

Application of chlortetracycline in commercial pigs

  • Significantly improve the production performance of commercial pigs. 

  • Group A was the control group, and three different antibiotics, chlortetracycline, flavomycin, and naramycin, were added to groups B, C, and D respectively. The average final weight and average daily weight gain of group B (chlortetracycline treatment group) were higher than those of other groups, the feed weight was lower than that of other groups, and the breeding efficiency was also the highest. 

  • Yang Yue will randomly select 160 healthy piglets weaned at 28 days of age and treat diarrhea with ricomycin, gentamicin + amoxicillin, enrofloxacin + amoxicillin, and chlortetracycline + amoxicillin. Prevention trials. The results showed that: chlortetracycline + amoxicillin had the best effectiveness in preventing diarrhea (71.7%).

Adding chlortetracycline to pig diets can improve the reproductive performance of sows, improve the performance of commercial meat pigs and control pig diarrhea. It is the first choice drug for health care and disease prevention in pig farms.

Medication plan and purpose of chlortetracycline in pig farm health care

  • Breeding pigs: mixed feeding before and after farrowing to purify sows of pathogens, protect their intestines, and reduce the occurrence of obstetric diseases in sows. 
  • Piglets: Mixed feeding before and after weaning to prevent and treat diarrheal diseases in piglets, relieve stress, and lay a solid foundation for the nursery period. 
  • Nursery pigs: Mixed feeding before and after moving to a group can reduce the chance of pathogen attachment and bringing pathogens into the new pig house, and relieve stress. 
  • Fattening pigs: Mixed feeding before and after fattening can reduce the outbreak of respiratory diseases and increase the fattening effect.

Precautions when using chlortetracycline

  • When used as a growth promoter, it should be added legally in accordance with the dosage, use objects, drug withdrawal period and other regulations in the standards promulgated by the Ministry of Agriculture; 

  • The appropriate course of treatment is 14 days for disease prevention and 5-7 days for disease treatment.

Recommended Applications

  • Pigs: used for asthma, chlamydia, epierythrozoonosis infections and ileitis. 
  • Poultry: Infectious diseases caused by Escherichia coli and Mycoplasma.

 individual preventive medication regimen
  1. For those weighing less than 20kg, 1g/head·day, for 3-5 days; 
  2. When the body weight is about 50kg, 2g/head·day, for 3-5 days; 
  3. Body weight is about 80kg, 3g/head·day, use for 3-5 days; 
  4. When the body weight is about 100kg, 4g/head·day, for 3-5 days; 
  5. For multiparous sows, 5g/head·day, for 3-5 days; 


Mixed feeding: Add 0.5-2kg per ton of feed for 5-7 days. 
Mixed drink: 1-2g for livestock and poultry per 1L of water, use for 5-7 days.