113 EFFECT OF PLANT PROTEIN ON DEVELOPMENT AND QUALITY OF CULTURED IN VITRO PORCINE ZYGOTES

Abstract

Basic culture media are usually supplemented with serum albumin or serum, which contain amino acids that play an important role as energy sources, osmoregulators, and pH stabilizers. However, the presence of undefined serum in culture media introduces a variation from batch to batch and increases viral or prion contamination risk. The aim of the present study was to investigate the possibility of using plant protein substitute (PP) in place of bovine serum albumin (BSA) during in vitro culture of porcine zygotes. The PP is a mixture of several plant proteins and soya lecithin prepared using a high pressure homogenization process. The experiment was done on pig zygotes obtained surgically from superovulated gilts at 24–26 h after insemination. Morphologically normal zygotes were cultured in vitro in 5% CO₂ in air at 39° in NCSU-23 medium supplemented with: 0.002 g mL^–1 (group 1), 0.004 g mL^–1 (group 2), 0.008 g mL^–1 (group 3) PP or 0.004 g mL^–1 BSA (control group). Embryo quality criteria were developmental competence (cleavage, morula and blastocyst rates), total cell number per blastocyst and degree of apoptosis as assessed by TUNEL method. Results were analyzed by Chi-square test. There were no differences in cleavage rates on Day 2 between zygotes cultured in NCSU-23 medium supplemented with PP (86.0, 88.0, 84.8; group 1 to 3, respectively) and BSA (91.0%, control group). Culture with 0.008 g mL^–1 PP increased morula (85.7%) and blastocyst (69.2%) production as compared with control (75.0% and 56.3%, respectively; P < 0.05) and 0.002 g mL^–1 PP (79.5% and 51.8%, respectively; P < 0.05). The mean number of cells in Day 7 blastocysts cultured in NCSU-23 medium + 0.004 g mL^–1 BSA was lower (P < 0.05) than in NCSU-23 + 0.004 g mL^–1 PP (39.1 v. 43.7, respectively). The blastocysts cultured in NCSU-23 medium + 0.002 g mL^–1 PP had higher average number of apoptotic nuclei (13.0) as compared with the control (6.5) and 0.004 g mL^–1 PP (6.9). In conclusion, this study suggest the positive effect of PP on development in vitro of porcine zygotes to the morula/blastocyst stage. However, further studies are required to determine the quality of the embryos cultured with PP.

This study was supported by Scientific Net of Animal Reproduction Biotechnology.