Evaluation of dietary zinc on antioxidant-related gene expression, antioxidant capability and immunity of soft-shelled turtles Pelodiscussinensis.

Zinc (Zn) plays a role in the antioxidant capacity and immunity of aquatic animals. A twelve-week feeding experiment was performed to estimate the impact of dietary zinc on antioxidant enzyme-related gene expression, antioxidant enzyme activity and non-specific immune functions of soft-shelled turtles, Pelodiscus sinensis. Six fishmeal-based experimental diets with 32.45% protein were formulated, which contained 35.43, 46.23, 55.38, 66.74, 75.06 and 85.24 mg/kg Zn, respectively. Catalase (CAT), glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) levels improved with an elevation in dietary Zn from 35.43 to 55.38 mg/kg and then reduced when dietary Zn was further elevated. The expression levels of Nrf2 and antioxidant-related genes CuZnSOD, MnSOD, CAT, GPX1, GPX2, GPX3 and GPX4 escalated with elevating Zn concentration up to 55.38 mg/kg in diets and then reduced as dietary Zn elevated. The expression levels of Kelch-like ECH-associating protein 1 (keap1) showed a reverse trend with that of Nrf2. The contents of malondialdehyde (MDA) in the 55.38 and 66.74 mg/kg Zn diet-fed groups were the lowest. Alkaline phosphatase activity (AKP), superoxide anion (O2-), lysozyme activity and total antioxidant capacity (T-AOC) improved with an escalation in dietary Zn concentration up to 66.74 mg/kg. Optimal dietary Zn improved antioxidant capability, immunity, and antioxidant enzyme-related gene expression. The dietary Zn demand for soft-shelled turtles were 60.93 and 61.63 mg/kg, based on second regression analysis of SOD and T-AOC activity, respectively.

Quality and antioxidant response of gilthead seabream (Sparus aurata L.) to dietary supplements of fenugreek (Trigonella foenum graecum) alone or combined with probiotic strains.

The present study was conducted to determine the potential effect of the dietary intake of fenugreek (Trigonella foenum graecum) seeds alone or in combination with Bacillus licheniformis, Lactobacillus plantarum or B. subtilis on gilthead seabream quality and antioxidant response after 2 and 3 weeks of experimental feeding. The results showed that the supplements did not affect the percentage of the fatty acid profiles of muscle, demonstrating that all the additives tested can be administrated without any negative effect on biochemical composition and quality of gilthead seabream. The quantification of thiobarbituric acid reactive substances in muscle demonstrated the significant beneficial effect of the experimental diets compared with the control one. Besides, an increase in superoxide dismutase and catalase in liver was recorded after 3 weeks of administration of experimental diets. Furthermore, real time qPCR revealed that dietary supplementation with FEBS significantly enhances the expression of scavenging enzymes, such as cat and gr genes in the liver after 3 weeks. The findings suggest that the administration of fenugreek supplement alone or combined with probiotic strains could be considered as a good source of natural antioxidants and as a functional aquafeed ingredient for gilthead seabream.

Magnolol additive as a replacer of antibiotic enhances the growth performance of Linwu ducks.

Magnolol rich in Magnolia officinalis is a bioactive polyphenolic compound. The aim of this study was to examine the effects of magnolol additive (MA) on growth performance, expression levels of antioxidant-related genes, and intestinal mucosal morphology of Linwu ducks aged from 49 to 70 days, comparing with that of an antibiotic additive (colistin sulfate [CS]). A total of 275, 49-day-old ducks were assigned to 5 groups with 5 cages of 11 ducks each and fed diets supplemented with 0, 100, 200 and 300 mg of MA/kg and 300 mg of CS/kg for 3 weeks, respectively. The results showed that the average daily body weight gain (ADG) was increased significantly in MA-fed groups (200 and 300 mg/kg), compared with the basal diet (BD) group (P < 0.05). The mRNA levels of superoxide dismutase-1 (SOD1), manganese superoxide dismutase-2 (MnSOD2) and catalase (CAT) were also increased significantly in MA groups (P < 0.05). In addition, hematoxylin and eosin staining revealed that Linwu ducks fed the diets with MA had more intact intestinal mucosa than those fed the BD and CS diets. In addition, ileal villus height, ileal villus height/crypt depth ratio (V/C) and duodenal V/C were also improved significantly (P < 0.05). Taken together, these data demonstrated that MA is an effective feed additive to enhance the growth performance of the Linwu ducks by improving the antioxidant and intestinal mucosal status, suggesting that MA will be a potential additive to replace antibiotic (CS).