Source: Foreign Animal Husbandry, Pig and Poultry, No.01,2019

Abstract: This paper introduces the application of antibiotics in chicken production, and its influence on chicken production performance, immune function, intestinal flora, poultry product quality, drug residue and drug resistance, and analyzes the application prospect and future development direction of antibiotics in chicken industry.

Key words: antibiotics; chicken; production performance; immune function; drug residue; drug resistance

Middle Figure Classification No.: S831 Document logo code: C Article No.: 1001-0769 (2019) 01-0056-03

Antibiotics or antibacterial drugs can inhibit and kill bacterial microorganisms at certain concentrations.Moore et al reported for the first time that the addition of antibiotics in feed significantly improved the daily weight gain [1] in broilers.Subsequently, similar reports have gradually increased.In the 1990s, the research of antimicrobial drugs in the chicken industry began in China. Now, more than 20 antibiotics have been widely used, playing an important role in promoting chicken production and preventing and controlling diseases.The research progress of the influence of antibiotics on chickens is introduced as follows.

1; Effect of antibiotics on chicken production performance

Yellow, dynamycin, bacidin zinc, amamycin, etc., can be used to promote growth, the mechanism is: inhibiting or killing chicken intestinal bacteria, hinder the proliferation of intestinal harmful bacteria, reduce the incidence; make animal intestinal wall thin, enhance intestinal mucosa permeability, accelerate the absorption of nutrients; inhibit intestinal microbial growth and activity, reduce microbial consumption of nutrients and energy, and increase the availability of nutrients in chickens; inhibit intestinal harmful bacteria produce harmful metabolites [2].Anshengying et al added antibiotics to feed egg chicks, which increased their body weight by 6.24% at the end of the trial period, and reduced the frequency of diarrhea by [3].Wan Jianmei et al added different doses of Virginamycin and enricamycin in the basic diet of 1-day old AA broilers, which significantly increased the average daily weight gain of 11 to 20 days old broilers and the average daily feed intake of 22 to 41 days old broilers; adding flavamycin (5 mg / kg) significantly increased the average daily weight gain of 22 to 41-day old broilers.Ni Jiang et al. added 4 mg / kg lincomycin and 50 mg / kg zinc; and 20 mg / kg colistin for 26 d, which significantly increased the daily weight gain [5].Wang Manhong et al. added enlamycin, bacracin zinc and naceptide for 42, d respectively in 1-day old AA chicken diet, which had significant growth-promoting effects, with the average daily weight increase and feed intake increased, and the meat ratio decreased by [6].

2; Effects of antibiotics on the immune function in chickens

The immune function of livestock and poultry plays an important role in enhancing the disease resistance and reducing the occurrence of disease.Studies have shown that long-term use of antibiotics will inhibit the development of chicken immune organs, reduce their immune function and easy to infect diseases.Its immunosuppression mechanism is: directly killing intestinal microorganisms or inhibiting their growth, reducing the stimulation of intestinal epithelium and intestinal lymphoid tissue, thus reducing the activation state of the body immune system; interfering with immunoglobulin synthesis; reducing cell phagocytosis; and reducing the mitotic activity of body lymphocytes [7].Jin Jiushan et al. added 0.06%, 0.010% and 0.15% of chloramphenicol for 2 to 60 days old broilers, which had significant inhibitory effect on chicken dysentery and avian typhoid fever, but significantly inhibited and impaired [8] in organs, bone marrow and hemocytopoiesis.Zhang Rijun et al fed 1-day-old broilers a diet containing 150 mg / kg goldomycin, and the weight of thymus, spleen and bursa significantly reduced [9] at 42 days of age.Guo Xinhua et al. added 150 mg / kg of gilomycin in the feed of 1-day-old AA males, significantly inhibiting the development of organs such as bursa, humoral immune response, and conversion rate of T lymphocytes and B lymphocytes.Ni Jiang et al. fed 4 mg / kg lincomycin hydrochloride, 50 mg and 20 mg / kg broilers respectively, and the bursac index and the thymus index and spleen index did not change significantly. The secretion of IgA in each section of the three groups decreased significantly, and the amount of serum IgM in the bactereracin zinc group significantly decreased [5].However, Jia Yugang et al. added 50 mg / kg of gilomycin to 1-day-old male diet to increase the amount of immunoglobulin IgG and IgM in Tibetan chickens, promote the release of cytokine IL-2, IL-4 and INF-in serum, and thus enhance the immune function [11], contrary to other studies.

3; Effect of antibiotics on chicken intestinal flora

There are various microorganisms in the digestive tract of normal chickens, which maintain a dynamic balance through interaction, which is conducive to the growth and development of chickens.After the extensive use of antibiotics, the death and reduction of sensitive bacteria in the digestive tract disturb the pattern of mutual restriction between the bacterial flora, resulting in new infections.As a substance that can effectively inhibit microorganisms, antibacterial drugs can inhibit and kill all microorganisms in chickens, which can lead to digestive disorders and cause digestive tract diseases.Tong Jianming et al. added 100 mg / kg gilomycin to the basic diet of 1-day old AA chicken, the number of Lactobacillus and bifidobacterium in the rectum at 7 days was significantly less than the control group, there was no significant difference between the number of the two bacteria after 14 days of age; the number of Escherichia coli was significantly less than the control group at 7,14,21 and 28 days, and [12] with the control group later.The test of Zhou Yanmin et al showed that antibiotics significantly inhibited the jejunum, E. coli and Salmonella, and significantly inhibited Lactobacillus proliferation [13].Ma Yulong et al. fed 1-day-old corn soybean meal diet supplemented with 50 mg / kg aureomycin to AA chicks for 42 d, reducing the number of Clostridium enterica and E. coli, but produced no significant [14] on total aerobic bacteria, total anaerobic bacteria and Lactobacillus numbers.Wu opan et al added 20 mg / kg Virginiamycin to 1-day-old AA chicken diet, which reduced the polymorphism of intestinal flora, which decreased the 14-day-old ileal and cecal bands, and showed a large difference in bacterial map similarity [15].Xie et al added cephalosporin to the diet of 1-day-old yellow feather chicks and found that its inhibitory effect on L. lactis in the small intestine, but could significantly reduce the number of L. [16] in the rectum.Lei Xinjian added 200 mg / kg;;;;;;;; bactereracin zinc and 30 mg / kg Virginiamycin respectively, which significantly reduced the number of cechia coli and Lactobacillus in 42-day-old broilers.Yin Luyao et al added 0.1 g / kg of bacracin zinc premix for 70 d, which reduced the abundance of harmful bacteria in the cecum, but the abundance of the cecum microorganisms also decreased [18].There are also a few contrary reports that the addition of 20 mg / kg sulfate antienemy element can significantly increase the number of bifidobacterium [19] in the cecal contents of 21-day-old broilers.

4; Effect of antibiotics on poultry product quality

Chicken and egg quality are closely related to the nutritional value, and the effect of antibiotics on the quality of poultry products is inconsistent.At 60 days old, adding 5 mg / kg for 60 d can increase the muscle water loss rate and decrease the rate of cooked meat, and increase the content of unsaturated fatty acids, polyunsaturated fatty acids and essential fatty acids related to freshness and sweetness, indicating that antibiotics have a slightly adverse effect on the physical properties of meat quality and can improve the flavor [20] of chicken to a certain extent.Wan Jianmei et al added virinamycin and enlamycin in the 1-day-old AA chicken diet, which had no significant effect on slaughter performance or muscle quality, and flavamycin reduced the drip loss of [4] in chicken chest muscle.From 0.03% gilomycin to 56 days of age, the slaughter rate increased by 0.28%, 2.72%, 8.76%, chest muscle rate by 8.76%, and abdominal fat rate by 19.82% [21].In 40-day diet supplemented with 50 mg / kg of gilomycin for 70 d, the pectoral muscle rate increased by 19.00%, and the pectoral shear force and drip loss were significantly reduced by [22].Yang Minxin fed 45 mg / kg of gilomycin to a 1-day-old basic diet of AA broilers significantly reduced the loss of chest muscle pressure and significantly increased [23] with T-SOD vitality and T-AOC levels in leg muscle.The study of Zou Qiang et al on the same feeding time in different breeding modes showed that the masticatory detection value of anti-cage gushi chicken breast was significantly improved; but the tenderness and taste were better and the sensory assessment score significantly improved [24].Liu Wenlong et al. found that the total amount of volatile flavor substances, aldehydes, alcohols and ketones were significantly higher than free-range chickens than house chickens. Breeding without adding antibiotics could significantly improve the flavor content of [25] in eggs more than antibiotics.

5; Effect of antibiotics on residues in poultry products

In recent years, some enterprises pursue one-sided interests, and the abuse of antibiotics leads to the increasing accumulation of antibiotic residues in poultry products.Wang Chunyan et al found that tetracycline residue in chicken and eggs was 4.66 mg / kg and 7.5 mg / kg respectively, the detection rate was 33.3% and 60%; the highest residue of streptomycin in eggs was 0.7 mg / kg and the detection rate was 20% [26].Wang Chunlin et al. fed high-energy diet supplemented with 50 mg / kg of gilmomycin to 1-day-old chicken. Chicken had gilomycin residue in the liver and kidney, with the maximum amount of [27] in the liver.After 12 d, the residue of gilmycin in chest muscle was less than 0.10 g / g (maximum residue limit); and the residue in liver and kidney was 23 d respectively;;;;;;;;;;;;;;;;;; was lower than the corresponding maximum residue limit [28] after 28 d.Lin Xiaohua was equal to 173 pieces of livestock and poultry meat collected in Guangzhou from 2006 to 2008, the exceeding rate was 21.96%, and the content was 0.16 mg / kg~9.54 mg / kg [29].Yan Xiaofeng determined the residues of five tetracycline antibiotics in 50 egg samples, and found that tetracycline and doxycycline had residual [30] in the egg samples.Chen Lin et al. showed that with the extension of drug time, the accumulation of antibiotics in the chest muscle, leg muscle and liver, amoxicillin and antibiotics, amoxicillin and Doxycycline in resistant eggs, and more [31] in resistant eggs.Qiu Jinli et al. gave 250 mg/L to broilers of different days;;; and 333 mg/L of 50% hydrochloride soluble powder once a day for 5 d, the most in liver tissue and the highest residue in liver and muscle below [32] after 5 d withdrawal.

6; Effect of antibiotics on drug resistance in chicken

Long-term excessive use of antibiotics in livestock and poultry will produce multiple drug-resistant bacteria, so that the whole pathogenic microbial flora will gradually change to the direction of drug resistance to [33].In recent years, the emergence of drug resistance in chicken-derived bacteria is becoming more and more serious, the drug-resistant strains are increasing, the drug resistance spectrum is becoming more and more wide, and the sensitivity to antibiotics is reduced, which brings difficulties to disease prevention and control.Liu Jinhua et al. 116 S. aureus strains isolated from some chicken farms in Beijing and Hebei found different degrees of drug resistance, mainly multiple resistance, and drug resistant S. aureus has a trend of increasing year by year [34].Zhang Xiuying et al. isolated 25 Salmonella strains from some chicken farms in Jiangxi, Liaoning and Guangdong, were only sensitive to kanamycin and ceftriaxone, and resistance rates to nalidixic acid, streptomycin, tetracycline, sulfa, cotrimoxazole, amoxicillin, ampicillin and some fluoroquinolones were greater than 50% [35].Xue Yuan et al. found that 30 E. coli strains isolated in Harbin had different sensitivity to 18 antibiotics, severe multiple drug resistance, amoxicillin / potassium clavulanate, ampicillin and ciprofloxacin was 100%, and highly sensitive [36] to amtreonam, amomycin and polymyxin B.Wang Qiwen et al. isolated 10 strains of streptococcus from dead poultry organs, completely resistant to nalidixic acid and lomesloxacin, highly sensitive to kanamycin, polymyxin, lecloxacin, novovomycin, vancomycin and meloxicillin, and have certain resistance [37] to many other antibiotics.Qu Ping study found that 72 strains of jejuni have different degrees of resistance to quinolones, cephalosporins, tetracyclines are highly resistant, penicillin, sulfonamide are medium resistance, macrolide, aminoglycosides, lincoamides are low resistance [38].The field mixed coccidium, madurycin, chloropepyridine, halilomycin and complete resistance [39].

To sum up, the use of antibiotics in chicken industry can improve production performance, reduce disease, but long-term and extensive use of antibiotics not only affect the immune function and intestinal micro ecological balance, reduce the quality of meat and flavor, at the same time will produce bacterial resistance and drug residue in meat and eggs, affect chicken disease prevention and control and food safety, harm human health.In 1986, Sweden was the first to ban antibiotics in feed, and in 2006, the European Union banned antibiotics in livestock and poultry feed, and gradually around the world.In 2017, the World Health Organization called for the cessation of antibiotics to promote disease prevention and healthy growth in animals.Therefore, it is the general trend to actively carry out the research of antibiotic alternatives, combine with the application of other management measures and technologies, and promote the development of anti-resistant breeding, which will also become the development direction of the chicken industry in the future.

References: (39 articles, omitted)