High-moisture extrusion technology should be considered one of the best choices for producing plant-based meat substitutes with the rich fibrous structure offered by real animal meat products. Unfortunately, the extrusion process has been seen as a “black box” with limited information about what occurs inside, causing serious obstacles in developing meat substitutes. This study designed a high-moisture extrusion process and developed 10 new plant-based meat substitutes comparable to the fibrous structure of real animal meat. The study used the Feature-Augmented Principal Component Analysis (FA-PCA) method to visualize and understand the whole extrusion process in three ways systematically and accurately. It established six sets of mathematical models of the high-moisture extrusion process based on 8 000 pieces of data, including five types of parameters. The FA-PCA method improved the R2 values significantly compared with the PCA method. The Way 3 was the best to predict product quality (Z), demonstrating that the gradually molecular conformational changes (Yn´) were critical in controlling the final quality of the plant-based meat substitutes. Moreover, the first visualization platform software for the high-moisture extrusion process has been established to clearly show the “black box” by combining the virtual simulation technology. Through the software, some practice work such as equipment installation, parameter adjustment, equipment disassembly, and data prediction can be easily achieved.
Comprehending the genetic basis of economically important traits is of significant importance to enhance livestock breeding. In domestic ruminants, hornlessness is becoming a more desirable trait since horns could lead to accidental injuries to animals and producers. Recent studies have identified the relaxin family peptide receptor 2 (RXFP2) as a primary candidate gene associated with the presence and absence of horns in sheep. However, no sufficient molecular biology-based analyses were performed to validate the association and function of RXFP2 in sheep. Noticeably, previous studies in both humans and mice have provided evidence supporting the involvement of RXFP2 in testicular descent. To validate the potential function of the RXFP2 gene in sheep, we used the CRISPR/Cas9 technology to obtain RXFP2-disrupted sheep individuals. Initially, highly efficient sgRNAs, targeting RXFP2, were screening through in vitro cleavage assays and cellular assessments. Then, two RXFP2-disrupted lambs were generated by intracytoplasmic microinjection of CRISPR/Cas9-sg1 ribonucleoprotein, with an efficiency of 81.84 and 37.17%, respectively. No potential off-target events were detected. Western blot analysis showed that RXFP2 expression was significantly reduced in the pedicle skin of edited lambs (P=0.034). Intriguingly, although the partial disruption of RXFP2 did not affect the horn phenotype in sheep, it led to an obvious unilateral cryptorchidism. These results provide evidence for a hitherto ambiguous link between both horn and testicular development. In conclusion, this study represents the first successful generation of cryptorchid sheep models via the disruption of RXFP2 using CRISPR/Cas9. These findings provide new insights into the roles of RXFP2, whose partial disruption is associated with testicular descent rather than horn formation.