Vitamin D (VD) plays a vital role in various physiological processes in addition to its classic functions on maintaining the balance of Ca and P metabolism. However, there still are gaps to understand in depth the issues on the precise requirement, metabolic processes and physiological functions of VD in fish. In this study, we investigated the effects of VD on the growth, intestinal health, host immunity and metabolism in turbot (Scophthalmus maximus L.), one important commercial carnivorous fish in aquaculture, through the supplementation of different doses of dietary VD3 (0, 200, 400, 800 and 1600 μg VD3/kg diet). According to our results, the optimal VD3 level in the feed for turbot growth was estimated to be around 400 μg/kg, whereas VD3 deficiency or overdose in diets induced the intestinal inflammation, lowered the diversity of gut microbiota and impaired the host resistance to bacterial infection in turbot. Moreover, the level of 1α,25(OH)2D3, the active metabolite of VD3, reached a peak value in the turbot serum in the 400 μg group, although the concentrations of Ca and phosphate in the turbot were stable in all groups. Finally, the deficiency of dietary VD3 disturbed the nutritional metabolism in turbot, especially the metabolism of lipids and glucose. In conclusion, this study evaluated the optimal dose of dietary VD3 for turbot and provided the evidence that VD has a significant impact on intestinal health, host immunity and nutritional metabolism in fish, which deepened our understanding on the physiological functions and metabolism of VD3 in fish.

We measured the offsets of six stream valleys, of 30 to 90 m, along the northwest-southeast trending, left-lateral Haiyuan strike-slip fault, in north-central China. Minimum ages of these offsets were determined to estimate lower bounds for the Holocene slip rate. The most reliable bounds are 7.6 ± 1.0 and 6.7 ± 1.0 mm/yr, with three others that are smaller (3.4 ± 0.7, 3.5 ± 0.9, and 4.1 ± 0.4 mm/yr) and one large value (16.4 ± 5.9 mm/yr) that we doubt. Thus, the average Holocene slip rate of the Haiyuan fault is larger than 6 mm/yr and probably exceeds 7 mm/yr. If the average slip rate of 5 to 10 mm/yr for the Quaternary Period is applicable to the Holocene Epoch, the average rate is 8 ± 2 mm/yr.

The Wenling Humped Cattle (WH) are a local breed of the Zhejiang Province, where they originated; the mild climatic conditions (temperature and rainfall) and the availability of food in the region helped the development of this population. The average body weight of adult males is 430 kg, and that of females 290 kg.

The Grassland Red Cattle (GR) are a double purpose (milk and meat) population well adapted to the pastureland conditions of northern China, where they graze during all seasons. The average body weight is 760 kg for adult males and 450 kg for females. The average lactation yield is estimated at 1800 kg with a 4% fat content.