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As most teleosts are unable to synthesize vitamin C, supplemental diets containing vitamin C diets play a crucial role in fish health. The aim of this study was to investigate the effect of dietary vitamin C on the intestinal enzyme activity and intestinal microbiota of silver pomfre (Pampus argenteus). Four experimental diets were supplemented with basic diets containing 300 mg of vitamin C/kg (group tjl3), 600 mg of vitamin C/kg (group tjl6), and 1200 mg of vitamin C/kg (group tjl12), as well as vitamin C-free supplemental basic diet (group tjl0), respectively. The four diets were fed to juvenile P. argenteus (average initial weight: 4.68 ± 0.93 g) for 6 weeks. The results showed that the activity of SOD (superoxide dismutase) and CAT (catalase) increased significantly while that of MDA (malondialdehyde) decreased significantly in group tjl3 compared to vitamin group tjl0. At the genus level, groups tjl0, tjl6, and tjl12 contained the same dominant microbial community, Stenotrophomonas, Photobacterium, and Vibrio, whereas group tjl3 was dominated by Stenotrophomonas, Delftia, and Bacteroides. Among the fish fed with a basic diet containing 300 mg of vitamin C/kg, the intestines exhibited a notable abundance of probiotic bacteria, including lactic acid bacteria (Lactobacillus) and Bacillus. The abundance of Aeromonas in groups tjl3 and tjl6 was lower than that of the vitamin C-free supplemental basic diet group, whereas Aeromonas was not detected in group tjl12. In addition, a causative agent of the disease outbreak in cultured P. argenteus, Photobacterium damselae subsp. Damselae (PDD) was the dominant microbiota community in groups tjl0, tjl6 and tjl12, whereas the abundance of PDD in group tjl3 was the lowest among the diets. Taken together, the diets supplied with vitamin C could influence the composition microbial community of P. argenteus. The low level of vitamin C (300 mg of vitamin C/kg per basic diet) supplementation could not only improve the antioxidant capacity but also resist the invasion of pathogenic bacteria. [ABSTRACT FROM AUTHOR]

This paper mainly introduces the key technology of raw material selection, raw material pretreatment, carding machine, drawing frame, roving frame and spinning frame on the semi-combed. Contrastive analysis of the pretreatment process and hair equipment , optimal selection of hair additives and hair process; putting forward some suggestions on the applicability of carding machine roll feeding and loose fiber feeding method , and on the machinery reformation and process adjustment of carding machine. Combined with the gliding draft technology of drawing frame, putting forward an effective solution to thread breakage of flocked products for the first time; and then compares the structural characteristics of wool and cotton roving frame and spinning frame, especially introduces the transformation of cotton roving frame and spinning frame. Selection and main transformation of equipment in this paper could only be used as a reference. [ABSTRACT FROM AUTHOR]

This paper mainly introduces the independent development machine of the TJGDQHXZSR- 09 villi drawing machine, the drawing machine mainly includes automatic feeding, pretreatment, drawing, setting and drying system, by using this machine continuous processing of the staple fiber such as yak hair and so on can be implemented. It also introduces one modification measure of magazine processing system, the mainly technical features of it include: the duplex bands molding transformation of drawing frame, duplex yarn molding processing technology of roving frame and spinning frame, the effects on the spinning frame's feeding of twist and twistless roving frame is analyzed. Tensile yak hair fiber in transforming semi-combed fluffy magazine processing system is development 10.4 tex X2X2 composite yarns. After the test of knitting piece, the pilling resistance of the product is improved obviously. [ABSTRACT FROM AUTHOR]