Bacterial growth control during swine semen production is a challenge for Semen Processing Center. Raw ejaculates are processed at temperatures favorable for microbial multiplication. Prophylactic antibiotics addition to semen extender prevents undesirable bacterial growth. This use enhances the risk of selecting bacterial resistance to antibiotics. IMV-Technologies take advantage of commonly used bacteriostatic molecules in plastics compositions to include it into the semen bag: BactiBag. This allows inhibition of bacterial growth and prevents release of lipopolysaccharides inherent to bacterial death.
To test the performances of BactiBag in field conditions two consecutive studies were carried out. Study 1 was designed to assess whether BactiBag affects semen quality and reproductive performances, while Study 2 aimed at assessing the reproductive performance of sows inseminated with semen extended with an antibiotic-free media and stored in BactiBag. For both studies, semen doses were used within three days after collection; Computed Assisted Semen Analysis and Flow Cytometry analysis were carried out three days after collection to evaluate semen quality. Continuous variables were statistically analyzed using Mixed Models Analysis of Variance. Farrowing rates compared with the Fisher-Exact test.
In Study 1, ejaculates from Pietrain boars of proven fertility were diluted in NutriXcell+ containing antibiotics and split into two equal parts: one stored in standard GTB® bag (Control) and the other in BactiBag. There were no differences between Control and BactiBag in bacterial charge (12351 vs 7050 count, p-value=0.3851), spermatozoa mobility (77.6 vs 74.5%, p-value=0.2304) or viability (88.2 vs 88.3%, p-value=0.8440). To evaluate the reproductive performances of the BactiBag, 384 sows were randomly assigned to either Control group (223) or BactiBag (161). Sows inseminated with BactiBag stored semen had a higher farrowing rate than Controls (95.7 vs 87.0%, p-value=0.0042) while litter-size was not different (14.0 vs 14.6 piglets, p-value=0.2569 for BactiBag and Control respectively).
In Study 2, ejaculates from Pietrain boars of proven fertility were split into two equal parts: one part was extended in a BTS media supplemented with antibiotics (lincomycine 75mg.L-1; spectinomycine 75mg.L-1) and stored in GTB® bag (Control); the second part was extended in a BTS media without antibiotics and stored in BactiBag. There were no differences in bacterial charge between the two groups (10204 vs 13829 count, p-value=0.3851). Remarkably, BactiBag stored semen exhibited higher mobility percentage (73.0 vs 75.3%, p-value=0.0144) and viability (72.2% vs 74.7%, p-value=0.0002). The reproductive performance at field level was assessed through 203 sows (115 for Controls and 88 for BactiBag). There were no differences neither in farrowing rate (92.2 vs 90.9%, p-value=0.8015) nor in litter size (14.4 vs 14.9 piglets, p-value=0.5367) between Control and BactiBag groups, respectively.
Altogether, these two experiments show that BactiBag is a suitable aid to limit the use of antibiotics in artificial insemination in pigs.