Xenogenesis has been identified as a potential alternative for hybrid catfish (channel catfish, Ictalurus punctatus ♀ × blue catfish, I. furcatus ♂) embryo production. The xenogenesis process can be accomplished by transplanting primordial germ cells, spermatogonial or oogonial stem cells derived from a donor diploid fish into a sterile recipient . Xenogenesis for hybrid catfish embryo production has been accomplished using triploid channel catfish as hosts. However, having a host with a short maturation time and smaller body size than channel catfish would be ideal for rapid commercial application . Hence, the present study was conducted to assess the effectiveness of triploid white catfish (Ameiurus catus) as a host species to transplant blue catfish stem cells (BSCs) and channel catfish stem cells (CSCs) to produce xenogeneic broodstock. Triploid white catfish fry were injected with either BSCs or CSCs labeled with PKH26 dye from 0 to 12 days post-hatch (DPH). Then at 45 and 90 DPH, growth performance and survival of recipients were evaluated. Colonization of donor cells was evaluated in recipients using PKH26 dye fluorescence to calculate percent cell and cluster areas . PCR was utilized to determine the percentage xenogens .
No significant differences in body weight and total length of fry were detected among injection day treatments when sampled at 45 and 90 DPH (P > 0.05). Overall, survival increased between 0 to 5.5 DPH when white catfish triploids were injected with BSCs or CSCs and highest survival was reported for fry injected between 4.0 to 5.5 DPH. After 5.5 DPH, survival remained high (≥ 81.2%). At both 45 and 90 DPH, cell and cluster area increased for recipients injected from 0 to 5.2 DPH and highest values reported between 4.0 to 5.2 DPH. Thereafter, fluorescent cell and cluster area in the host declined with no further decrease after 10 DPH. At 45 DPH, the highest percentage of xenogens were detected in BSCs and CSCs treatments for fry injected between 4 .0 to 5.0 and 3.0 to 5.0 DPH , respectively. At 90 DPH, the greatest mean number of xenogenic individuals detected was for fry injected from 4.0 to 6.0 DPH in both BSCs and CSCs treatments. The current study demonstrated the suitability of white catfish as a host species when stem cells were transplanted between 4.0 to 6.0 DPH, and these findings allow enhanced efficiency of production of xenogenic catfish carrying gametes of either blue or channel catfish.