Sensitivity Study Of Antibiotics In Boar Semen Diluent

The technology of semen preservation plays an important role in the process of swine artificial insemination(AI), and only through continue to improve the effect of swine semen storage at room temperature, can make swine AI technology play a greater role in swine breeding industry. As the using and extension of swine AI technology in our country, the need of diluent during semen preservation at room temperature is increased greatly. However, the diluent that our country with independent intellectual property rights have many problems during semen preservation in room temperature, such as short preservation time, low sperm motility and so on. These problems are related to the irrational use of antibiotics and the bacteria-infested inhibit sperm normal metabolic activities. Therefore, the aim of this study is to provide a theoretical basis for the using of antibiotics in swine semen preservation at room temperature, and based on this theory, develop a diluent which with independent intellectual property rights, low cost and well quality. This is significance to China’s pig farming industry.In order to select an antibiotic usage programs which with well and stable inhibition effect on common bacteria, we cultured the bacteria of boar semen, then isolated and purified these bacteria, after morphological analysis and physical culture identification, the bacterial species were identified. We also calculated the proportion of each bacterial species on plate by count method and the most probable number method. Based on the results, combined with the joint use of antibiotics to prevent incompatible strains and antibiotic susceptibility response strength, we formulated an antibiotic using program and test its effect of semen preservation. The following are the main results in this study:1. Nine species microbial strains were isolated from boar semen, include seven bacteria species and two filamentous fungi species. The seven bacteria species were Escherichia Castellani and Chalmers, Enterobacter Hormaeche and Edwards, Salmonella Lignieres, Shigella Castellani and Chalmers, a gram-positive aerobic and facultative anaerobic bacteria species Staphylococcus and two species Proteus Hauser, respectively. The two filamentous fungi were Aspergillus Micheli and Penicillium Link. The total number of microorganism in boar semen was 7.0 ~ 7.2 × 103 cells / mL, formed by 15.27% Escherichia, 9.60% Proteus vulgaris accounting, 14.83% Proteus mirabilis, 6.74% Enterobacter, 12.52% Salmonella, 3.46% Shigella, 12.58% Staphylococcus, 12.75% Penicillium and 12.24% Aspergillus.2. The inhibitory effect of Ciprofloxacin(inhibition zone diameter was 28.3 mm), Cotrimoxazole(inhibition zone diameter was 31.2 mm) and Chloromycetin(inhibition zone diameter was 26.7 mm) on Escherichia were significant higher(P < 0.05) than other antibiotics. The inhibitory effect of Ciprofloxacin(inhibition zone diameter was 34.7 mm) and Amikacin(inhibition zone diameter was 32.1 mm) on Proteus vulgaris were significant higher than other antibiotics(P < 0.05). The inhibitory effect of Cotrimoxazole(inhibition zone diameter was 38.1 mm), Ampicillin(inhibition zone diameter was 45.1 mm), Amikacin(inhibition zone diameter was 38.7 mm) and Cefazolin(inhibition zone diameter was 39.2 mm) on Proteus marabilis were significant higher than other antibiotics(P < 0.05). The inhibitory effect of Amikacin(inhibition zone diameter was 45.3 mm) on Enterobacter were significant higher than other antibiotics(P < 0.05). The inhibitory effect of Chloromycetin(inhibition zone diameter was 38.7 mm) on Salmonella were significant higher than other antibiotics(P < 0.05). The inhibitory effect of Gentamicin(inhibition zone diameter was 37.9 mm) on Shigella were significant higher than other antibiotics(P < 0.05). The inhibitory effect of Ciprofloxacin(inhibition zone diameter was 20.1 mm) and Cotrimoxazole(inhibition zone diameter was 22.9 mm) on Staphylococcus were significant higher than other antibiotics(P < 0.05). The inhibitory effect of Cotrimoxazole(inhibition zone diameter was 1.8 mm) and Erythromycin(inhibition zone diameter was 2.3 mm) on Penicillium were significant higher than other antibiotics(P < 0.05). While Aspergillus was not sensitive to Amikacin, Chloramphenicol, Gentamicin and Penicillin, and there were no significant difference of inhibitory effect among other antibiotics(P > 0.05).3. There were five groups in this study, group Cotrimoxazole 25,000 IU/L + Gentamicin 200,000 IU/L, group Ciprofloxacin + Amikacin 400,000 IU/L+ Chloromycetin 400,000 IU/L group Ciprofloxacin 600,000 IU/L+ Cotrimoxazole 16,000 IU/L + Cefazolin 400,000 IU/L group Penicillin 1,000,000 IU/L and the control group. There was no significant difference of sperm motility among the five groups after one day’s preservation(P > 0.05). However, after one and half days’ preservation, the sperm motility of first and second group were significantly higher than other groups(P < 0.05) and after three days’ preservation, the sperm motility of first group was significantly higher than other groups(P < 0.05). The longest effective retention time was group Cotrimoxazole + Gentamicin, followed by group Ciprofloxacin + Amikacin + Chloramphenicol, while the shortest effective retention time were group Penicillin and control group. The best antibiotic program of semen preservation is Cotrimoxazole 25,000 IU / L + 200,000 IU / Lgentamicin.