Yang Shanxin, Liu Tingting, Mo Jianxin, Yang Huaqiang, Wang Haoqiang, Huang Guangyan, Cai Gengyuan, Wu Zhenfang, Zhang Xianwei
College of Animal Science, South China Agricultural University, Guangzhou, 510642, China.
Yunfu Branch, Guangdong Laboratory for Lingnan Modern Agriculture, Yunfu, 527400, China.
Transgenic Res. 2023 Apr;32(1-2):109-119. doi: 10.1007/s11248-023-00339-9. Epub 2023 Feb 21.
Novel transgenic (TG) pigs co-expressing three microbial enzymes, β-glucanase, xylanase, and phytase, in their salivary glands were previously generated, which exhibited reduced phosphorus and nitrogen emissions and improved growth performances. In the present study, we attempted to explore the age-related change of the TG enzymic activity, the residual activity of the enzymes in the simulated gastrointestinal tract, and the effect of the transgenes on the digestion of nitrogen and phosphorus content in the fiber-rich, plant-based diets. Results showed that all the three enzymes were stably expressed over the growing and finishing periods in the F2 generation TG pigs. In simulated gastric juice, all the three enzymes exhibited excellent gastrointestinal environment adaptability. The apparent total tract digestibility of phosphorus was increased by 69.05% and 499.64%, while fecal phosphate outputs were decreased by 56.66% and 37.32%, in the TG pigs compared with the wild-type littermates fed with low non-starch polysaccharides diets and high fiber diets, respectively. Over half of available phosphorus and water-soluble phosphorus in fecal phosphorus were reduced. We also found the performance of phosphorus, calcium, and nitrogen retention rates were significantly improved, resulting in faster growth performance in TG pigs. The results indicate that TG pigs can effectively digest the high-fiber diets and exhibit good growth performance compared with wild type pigs.
先前已培育出在唾液腺中共表达三种微生物酶（β-葡聚糖酶、木聚糖酶和植酸酶）的新型转基因（TG）猪，这些猪的磷和氮排放量减少，生长性能得到改善。在本研究中，我们试图探究TG酶活性随年龄的变化、酶在模拟胃肠道中的残留活性，以及转基因对富含纤维的植物性日粮中氮和磷含量消化的影响。结果表明，在F2代TG猪的生长育肥期，所有这三种酶均稳定表达。在模拟胃液中，所有这三种酶均表现出优异的胃肠道环境适应性。与分别饲喂低非淀粉多糖日粮和高纤维日粮的野生型同窝仔猪相比，TG猪的磷表观全肠道消化率分别提高了69.05%和499.64%，而粪便磷酸盐排出量分别降低了56.66%和37.32%。粪便磷中超过一半的有效磷和水溶性磷减少。我们还发现，TG猪的磷、钙和氮保留率显著提高，生长性能更快。结果表明，与野生型猪相比，TG猪能够有效消化高纤维日粮，并表现出良好的生长性能。
