Improvement of anti-nutritional effect resulting from β-glucanase specific expression in the parotid gland of transgenic pigs

Abstract

β-Glucan is the predominant anti-nutritional factors in monogastric animal feed. Although β-glucanase supplementation in diet can help to eliminate the adverse effects, enzyme stability is substantially modified during the feed manufacturing process. To determine whether the expression of endogenous β-glucanase gene (GLU) in vivo can improve digestibility of dietary β-glucan and absorption of nutrients, we successfully produced transgenic pigs via nuclear transfer which express the GLU from Paenibacillus polymyxa CP7 in the parotid gland. In three live transgenic founders, β-glucanase activities in the saliva were 3.2, 0.07 and 0.03 U/mL, respectively, and interestingly the enzyme activities increased in the pigs from 178 days old to 789 days old. From the feed the amount of gross energy, crude protein and crude fat absorbed by the transgenic pigs was significantly higher than the non-transgenic pigs. Meanwhile the moisture content of the feces was significantly reduced in transgenic pigs compared with the non-transgenic pigs. Furthermore, in all positive G1 pigs, β-glucanase activity was detectable and the highest enzyme activity reached 3.5 U/mL in saliva. Also, crude protein digestion was significantly higher in G1 transgenic pigs than in control pigs. Taken together, our data showed that the transgenic β-glucanase exerted its biological catalytic function in vivo in the saliva, and the improved performance of the transgenic pigs could be accurately passed on to the offspring, indicating a promising alternative approach to improving nutrient availability was established to improve utilization of livestock feed through transgenic animals.

Keywords: 1,3-1,4-β-Glucanase; Parotid gland; Transgenic pigs.