Evaluation of Alpha-Ketoglutarate Supplementation on the Improvement of Intestinal Antioxidant Capacity and Immune Response in Songpu Mirror Carp (Cyprinus carpio) After Infection With Aeromonas hydrophila.

As an intermediate substance of the tricarboxylic acid cycle and a precursor substance of glutamic acid synthesis, the effect of alpha-ketoglutarate on growth and protein synthesis has been extensively studied. However, its prevention and treatment of pathogenic bacteria and its mechanism have not yet been noticed. To evaluate the effects of alpha-ketoglutarate on intestinal antioxidant capacity and immune response of Songpu mirror carp, a total of 360 fish with an average initial weight of 6.54 ± 0.08 g were fed diets containing alpha-ketoglutarate with 1% for 8 weeks. At the end of the feeding trial, the fish were challenged with Aeromonas hydrophila for 2 weeks. The results indicated that alpha-ketoglutarate supplementation significantly increased the survival rate of carp after infection with Aeromonas hydrophila (P < 0.05), and the contents of immune digestion enzymes including lysozyme, alkaline phosphatase and the concentration of complement C4 were markedly enhanced after alpha-ketoglutarate supplementation (P < 0.05). Also, appropriate alpha-ketoglutarate increased the activities of total antioxidant capacity and catalase and prevented the up-regulation in the mRNA expression levels of pro-inflammatory cytokines including tumor necrosis factor-α, interleukin-1ß, interleukin-6, and interleukin-8 (P < 0.05). Furthermore, the mRNA expression levels of toll-like receptor 4 (TLR4), and nuclear factor kappa-B (NF-κB) were strikingly increased after infection with Aeromonas hydrophila (P < 0.05), while the TLR4 was strikingly decreased with alpha-ketoglutarate supplementation (P < 0.05). Moreover, the mRNA expression levels of tight junctions including claudin-1, claudin-3, claudin-7, claudin-11 and myosin light chain kinases (MLCK) were upregulated after alpha-ketoglutarate supplementation (P < 0.05). In summary, the appropriate alpha-ketoglutarate supplementation could increase survival rate, strengthen the intestinal enzyme immunosuppressive activities, antioxidant capacities and alleviate the intestinal inflammation, thereby promoting the intestinal immune responses and barrier functions of Songpu mirror carp via activating TLR4/MyD88/NF-κB and MLCK signaling pathways after infection with Aeromonas hydrophila.

Effects of dietary myo-inositol on growth, antioxidative capacity, and nonspecific immunity in skin mucus of taimen Hucho taimen fry.

In this study, the effects of dietary myo-inositol on the skin mucosal immunity and growth of taimen (Hucho taimen) fry were determined. Triplicate groups of 500 fish (initial weight 5.58 ± 0.15 g) were fed different diets containing graded levels of myo-inositol (28.75, 127.83, 343.83, 565.81, and 738.15 mg kg-1) until satiation for 56 days. Thereafter, the nonspecific skin mucus immune parameters, antioxidative capacity, and growth performance were measured. The skin mucus protein and the activities of alkaline phosphatase were significantly higher than those in the control group (P < 0.05). However, there were no significant differences in lysozyme activity among the treatments (P > 0.05). The antimicrobial activity and minimum inhibitory concentration of the skin mucus were increased significantly by myo-inositol supplementation (P < 0.05). The superoxide dismutase, catalase, and glutathione peroxidase activities were significantly elevated in the treatment groups (P < 0.05), whereas the malondialdehyde contents were significantly decreased (P < 0.05). Low-level myo-inositol (28.75 mg kg-1) led to a significantly lower weight gain, feed efficiency, condition factor, and survival rate compared with the other treatments (P < 0.05). In conclusion, dietary myo-inositol deficiency (28.75 mg kg-1) adversely affects the skin mucus immune parameters, antioxidative capacity, and growth performance of Hucho taimen fry.

Effects of traditional Chinese medicines on immunity and culturable gut microflora to Oncorhynchus masou.

The present study was conducted to evaluate the effect of dietary traditional Chinese medicines on the growth, immunity, and composition of culturable gut microflora in Oncorhynchus masou. Diets were formulated to contain no medicine (control), antitoxic decoction (A), general antiphlogistic decoction (B), or Herbae Artemisiae Capillariae decoction (C). Fish were manually fed twice daily till apparent satiation for 30 days. Compared with that in the control group, supplementation with the three kinds of Chinese herbal medicine enhanced fish growth significantly (P < 0.05). The activities of liver superoxide dismutase and glutathione peroxidase in the treatment groups were significantly higher compared with those in the control group (P < 0.05). The quantity of intestinal microflora was higher in the treatment groups compared with that in the control group. Moreover, there were some effects of dietary Chinese herbal medicine on the composition of intestinal microflora. Microflora of Pseudomonas sp., Psychrobacter sp., Microbacterium sp., Macrococcus sp., Burkholderia sp., and Arthrobacter sp. were found in the treatment groups, whereas there were none in the control group. There was a significant increase in their amounts in the treatment groups (P < 0.05). The three kinds of traditional Chinese medicines can improve the growth and immunity of Oncorhynchus masou and affect the quantity and composition of intestinal microflora.

Effect of N-carbamoylglutamate supplementation on the growth performance, antioxidant status and immune response of mirror carp (Cyprinus carpio) fed an arginine-deficient diet.

The present study was conducted to determine the effect of dietary N-carbamoylglutamate (NCG) supplementation on the growth performance, antioxidant capability and immune responses of mirror carp (Cyprinus carpio) fed an arginine (Arg)-deficient diet. A total of 630 mirror carp (41.65 ±â€¯0.14 g) were fed diets (Arg 1.24% of the diet) that were supplemented with 0.50% Arg (control diet) or graded levels of NCG at 0 (Arg deficiency diet), 0.04%, 0.08%, 0.12%, 0.16% and 0.20% for 8 weeks. The results showed that, compared with the control diet, the Arg-deficient diet supplementation with 0 NCG (1) decreased the final body weight (FWB), the weight gain rate (WGR) or the protein efficiency ratio (PER) and increased the feed conversion ratio (FCR); (2) decreased the concentration of Arg and nitric oxide (NO) and the activity of total nitric oxide synthetase (T-NOS) in the plasma; (3) decreased the activities of superoxide dismutase (SOD) in the proximal intestine (PI), catalase (CAT) in the PI and distal intestine (DI), and glutathione peroxidase (GPx) in PI and mid-intestine (MI) and increased the concentration of malondialdehyde (MDA) in the PI, MI and DI; and (4) decreased the activity of lysozyme in the plasma, increased the relative mRNA expression of tumor necrosis factor-α (TNF-α), interleukin1ß (IL-1ß) and interleukin 8 (IL-8) in the PI, MI and DI, and decreased the relative mRNA expression of interleukin 10 (IL-10) in the PI and MI, and transforming growth factor ß2 (TGF-ß2) in the PI, MI and DI. Compared with the Arg deficient-diet supplementation with 0 NCG, (1) 0.12% or 0.16% NCG increased the FBW, WGR and PER, and 0.16% NCG increased the FCR; (2) 0.08%-0.20% NCG increased the concentration of Arg, NO and the activity of T-NOS; (3) 0.08% NCG increased the activities of SOD in the PI and MI, and 0.12% NCG increased activities of CAT and GPx in the PI, MI and DI; and (4) 0.04%-0.20% NCG increased the activity of lysozyme, 0.04%-0.20% NCG decreased the relative mRNA expression of TNF-α, IL-1ß and IL-8 in the PI and MI, and 0.04%-0.20% NCG increased the relative mRNA expression of IL-10 and TGF-ß2 in the PI and MI. The present results indicated that dietary 0.12% or 0.16% NCG improved the growth performance, feed utilization, intestinal antioxidant capacity and immune response of mirror carp fed an Arg-deficient diet.

Effects of the supplementation of vitamin D3 on the growth and vitamin D metabolites in juvenile Siberian sturgeon (Acipenser baerii).

The objective of this study was to evaluate the effects of the supplementation of vitamin D3 on the growth, vitamin D metabolites, and osteocalcin secretion in juvenile Siberian sturgeon (Acipenser baerii). A 90-day growth trial was conducted with juvenile Siberian sturgeon (initial body weight 3.47 ± 0.14 g) fed seven isonitrogenous and isoenergetic practical diets (45% CP and 13% lipid) containing 60 (basal diet), 240, 450, 880, 1670, 3300, or 1.0 × 105 IU/kg feed (D60~D 1.0 × 105) vitamin D3. The results showed that weight gain and specific growth rate increased as the dietary vitamin D3 levels increased from 450 to 3300 IU/kg (P < 0.05). The fish fed with D1670 and D3300 diets had higher crude lipid and ash levels than the fish fed the D60 diet (P < 0.05). The fish fed D880, D1670, or D3300 diets had higher 25-OH-D3 and 1,25-(OH)2-D3 levels than the fish fed the D60 diet (P < 0.05). The fish fed D880, D1670, D3300, or D1.0 × 105 diets had higher osteocalcin levels than the fish fed the D60 diet (P < 0.05). Based on the broken line method analysis of weight gain and osteocalcin, the dietary vitamin D3 requirement of juvenile Siberian sturgeon was estimated to be 1683.30 and 1403.27 IU/kg per diet, respectively.