Omega-3 polyunsaturated fatty acids (ω-3 PUFAs) are essential components required for normal cellular function and have been shown to have important therapeutic and nutritional benefits in humans. But humans or mammals cannot naturally produce ω-3 PUFAs, due to the lack of the ω-3 fatty acid desaturase gene (fat-1 gene). Previously, fat-1 gene has been cloned from Caenorhabditis elegans and transferred into mice, pigs and sheep, but not yet into beef cattle. We attempt to transfer it into beef cattle. The object of this paper is to edit the fat-1 gene from C. elegans to express more efficiently in beef cattle and verify its biological function in mice model. As a result, the fat-1 gene from C. elegans was modified by synonymous codon usage and named it Bfat-1. We have demonstrated that degree of codon bias of Bfat-1 gene was increased in beef cattle. Moreover, Bfat-1 gene could be transiently expressed in mouse liver and muscle, the ω-6/ω-3 PUFAs ratio of 18 and 20 carbon was decreased significantly in liver (P<0.05), and the ratio of 20 carbon decreased significantly in muscle 24 and 72 h after injection (P<0.05). This confirms that the Bfat-1 gene modification was successful, and the protein encoded was able to catalyze the conversion of ω-6 PUFAs to ω-3 PUFAs.

This study investigated the effects of fermentation product containing phytase (FPP) that was fermented using waste vinegar residue (WVR) as substrate from Aspergillus ficuum NTG-23 on productive performance, egg quality, and phosphorus apparent metabolism of laying hens. First, 375 22-wk-old Jinghong hens were allocated into 5 treatments (5 replicates of 15 hens each) in an 8-wk experiment for evaluating the parameters of productive performance, egg quality, serum, and tibia. Experimental diets contained 4% FPP and 96% corn-soybean diet. The levels of dicalcium phosphate (DCP) were 1.34, 1.01, 0.67, 0.34 and 0%. Next, thirty 31-wk-old Jinghong hens were fed 5 types of diets for evaluating phosphorous apparent metabolism rate. Egg productive rate, egg weight, feed conversion ratio, Haugh unit, egg albumen height, serum calcium, tibia ash, tibia ash calcium and tibia breaking strength were not different significantly among 5 treatments. The significant difference of average daily feed intake was not appeared when the DCP content of corn-soybean-FPP diet was reduced to 0.67%; the eggshell hardness, eggshell thickness and serum phosphorus were not reduced significantly until the DCP content of corn-soybean-FPP diet was reduced to 0.34%. The yolk color was improved when the laying hens fed deficient DCP corn-soybean-FPP diet. A 22.14% reduction in excreta phosphorus was observed when the laying hens fed low phosphorus (0.67% DCP) corn-soybean-FPP diet. A 30% elevation of phosphorus apparent metabolism rate was obtained when the DCP content of corn-soybean-FPP diet was decreased from 1.34 to 1.01%. The reducing cost of layer diet was totalized about 120 CNY 1 000 kg-1 diet when the content of DCP was 0.67% in corn-soybean-FPP diet. These results indicated that FPP could be applied in laying hen as a potential, cost-effective and rational application of WVR.