Effects of choline supplementation on growth performance, liver histology, nonspecific immunity and related genes expression of hybrid grouper (♀ Epinephelus fuscoguttatus × â™‚ E. lanceolatu) fed with high-lipid diets.

This study was conducted to evaluate the effect of dietary choline levels on growth performance, liver histology, nonspecific immunity and related gene expression of hybrid grouper (♀ Epinephelus fuscoguttatus × â™‚ E. lanceolatus) fed with high-lipid diets. The fish (initial body weight 6.86 ± 0.01 g) were fed diets containing different choline levels (0, 5, 10, 15, and 20 g/kg, named D1, D2, D3, D4, and D5, respectively) for 8 weeks. The results showed that:(1) dietary choline levels had no significant effect on final body weight (FBW), feed conversion rate (FCR), visceral somatic index(VSI) and condition factor (CF) compared with the control group (P > 0.05). However, the hepato somatic index (HSI) in the D2 group was significantly lower than that in the control group and the survival rate (SR) in the D5 group was significantly lower (P < 0.05). (2) with dietary choline level increasing, alkaline phosphatase (AKP) and superoxide dismutase (SOD) of serum showed a tendency to increase and then decrease, and the maximum values were obtained in the D3 group, but the contents of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) decreased significantly (P < 0.05). (3) Immunoglobulin M (IgM), lysozyme (LYZ), catalase (CAT), total antioxidative capacity (T-AOC), and SOD in the liver all showed a trend of first increase and then decrease with the dietary choline level increased, and all of them achieved the maximum value at D4 group (P < 0.05), while reactive oxygen species (ROS) and malondialdehyde (MDA) in the liver decreased significantly (P < 0.05). (4) results from liver sections suggest that appropriate levels of choline can improve cell structure, compared with the control group, the damaged histological morphology of the liver was relieved and even returned to normal in D3 group. (5) in the D3 group, choline significantly upregulated the expression of hepatic sod and cat mRNA, whereas the expression of cat in the D5 group was significantly lower than that in the control group (P < 0.05); And the supply of choline stimulated a significant down-regulation of interleukin 6 (il6), myeloid differentiation factor 8 (myd88), toll-like receptor 22 (tlr22) mRNA expression levels in liver, while the expression of cellular tumor antigen p53 (p53) and interleukin 10 (il10) showed an upward and then downward trend (P < 0.05). In general, choline can improve the immunity of hybrid grouper by regulating non-specific immune-related enzyme activity and gene expression and reducing oxidative stress induced by high-lipid diet.

Impacts of tea polyphenols on growth, antioxidant capacity and immunity in juvenile hybrid grouper (Epinephelus fuscoguttatus ♀ × E. lanceolatus ♂) fed high-lipid diets.

The experiment aimed to investigate the alteration of tea polyphenols (TP) in growth and immunity for hybrid grouper (Epinephelus fuscoguttatus ♀ × E. lanceolatus ♂) fed high-lipid diets. Six concentrations of TP (0, 0.01, 0.02, 0.04, 0.08, 0.16%, named TP1 (basic diet control), TP2, TP3, TP4, TP5, TP6) were supplied in isonitrogenous (51%) and isolipidic (16.7%) experimental diets. These diets were fed to the juvenile grouper (8.68 ± 0.22 g) for 8 weeks. The results showed that dietary TP significantly increased the weight gain rate and specific growth rate (P < 0.05), compared with the control group. The protein efficiency ratio in TP4 group was significantly higher than that of the control group (P < 0.05). TP supplement in high-lipid diets increased antioxidant capacity in the serum (CAT, GSH-Px, T-AOC) and liver (SOD, CAT, GSH-Px, T-AOC). Additionally, dietary TP decreased oxidative stress (ROS, MDA) and improved immunity (ACP, AKP, LYS, IgM) in the liver. The histology of hepatic tissue indicated that dietary TP alleviated pathological symptoms caused by high-lipid diets. Compared with the control group, appropriate dietary TP significantly up-regulated expression of sod, cat, gsh-px, nrf2, keap1, hsp70, hsp90, myd88, tnfα and down-regulated expression of tlr22, il8, il1ß, il10 in the liver (P < 0.05). In the head kidney, expression of myd88, il1ß, tnfα and il6 were significantly up-regulated and expression of tlr22 and il10 were significantly down-regulated by dietary TP (P < 0.05). After the challenge of Vibrio harveyi, survival rate in higher doses of TP group (TP4 âˆ¼ TP6) was evidently higher, compared with the control group. In conclusion, TP supplement in high-lipid diets improved antioxidant capacity and enhanced immunity of grouper. We speculate that TP may play the role of an immunostimulant, enhancing immunity and disease resistance by cytokine-medicated immune responses. Based on the second-order regression, 0.092-0.106% tea polyphenols were recommended in juvenile grouper high-lipid diets.

The positive effects of dietary inositol on juvenile hybrid grouper (♀ Epinephelus fuscoguttatus × â™‚ E. lanceolatu) fed high-lipid diets: Growthperformance, antioxidant capacity and immunity.

The objective of the present research was to assess the influence of inositol supplementation on growth performance, histological morphology of liver, immunity and expression of immune-related genes in juvenile hybrid grouper (♀ Epinephelus fuscoguttatus × â™‚ E. lanceolatu). Hybrid grouper (initial weight 6.76 ± 0.34 g) were fed isonitrogenous and isolipidic diets (16%) with various inositol levels of 0.17 g/kg (J1, the control group), 0.62 g/kg (J2), 1.03 g/kg (J3), 1.78 g/kg (J4), 3.43 g/kg (J5), 6.59 g/kg (J6), respectively. The growth experiment lasted for 8 weeks. The results indicated that dietary inositol had a significant promoting effect on final mean body weight of the J5 and J6 groups and specific growth rate (SGR) of the J3, J4, J5 and J6 groups (P < 0.05). In the serum, superoxide dismutase (SOD) of the J4 group became significantly active compared with that of the control group (P < 0.05), while aspartate transaminase (AST), alanine transaminase (ALT) and alkaline phosphatase (AKP) activities in the inositol-treated groups showed distinctly decreased compared with those of the control group (P < 0.05). In the liver, dietary inositol could significantly increase the activities of SOD, catalase (CAT), lysozyme (LYZ) and the contents of total antioxidative capacity (T-AOC) and immunoglobulin M (IgM) (P < 0.05), and distinctly reduce the content of malondialdehyde (MDA) as well as reactive oxygen species (ROS) (P < 0.05). Compared with the control group, the damaged histological morphology of the liver was relieved and even returned to normal after an inositol increase (0.4-3.2 g/kg). In the liver, the remarkable up-regulation of SOD, CAT, glutathione peroxidase (GPX), heat shock protein70 (HSP70) and heat shock protein90 (HSP90) expression levels were stimulated by supply of inositol, while interleukin 6 (IL6), interleukin 8 (IL8) and transforming growth factor ß (TGF-ß) expression levels were down-regulated by supply of inositol. In head kidney, the mRNA of toll-like receptor 22 (TLR22), myeloid differentiation factor 88 (MyD88) and interleukin 1ß (IL1ß) expression levels were significantly down-regulated (P < 0.05), which could further lead to remarkable down-regulation of IL6 and tumor necrosis factor α (TNF-α) expression (P < 0.05). These results indicated that high-lipid diets with supply of inositol promoted growth, increased the antioxidant capacity, and suppressed the inflammation of the liver and head kidney by inhibiting the expression of pro-inflammation factors (IL6, IL8, TGF-ß and TNF-α). In conclusion, these results indicated that dietary inositol promoted growth, improved antioxidant capacity and immunity of hybrid grouper fed high-lipid diets. Based on SGR, broken-line regression analysis showed that 1.66 g/kg inositol supply was recommended in high-lipid diets of juvenile grouper.

The effects of dietary Lycium barbarum extract on growth performance, liver health and immune related genes expression in hybrid grouper (Epinephelus lanceolatus♂ × E. fuscoguttatus♀) fed high lipid diets.

Growth performance, hepatic morphology and antioxidant ability, and expressions of antioxidant, inflammatory and apoptosis related genes were investigated in hybrid grouper fed high lipid diets containing 0, 0.5, 1, 2 and 10 g kg-1Lycium barbarum extract (LBE) for 8-week feeding. The study showed that dietary LBE significantly increased weight gain rate (WGR) and specific growth rate (SGR) of fish (P < 0.05), the highest WGR and SGR were observed in fish fed 10.00 g kg-1 LBE diet. Dietary LBE improved liver morphology by decreasing hepatocyte necrosis and inflammatory cell infiltration induced by high lipid diets. Meanwhile, high lipid diets supplemented with 0.5-2 g kg-1 LBE improved hepatic antioxidant ability by increasing the expression of antioxidant genes (GPx and CAT) and decreasing Keap1 mRNA levels. Moreover, dietary supplementation with 0.50-2.00 g kg -1 LBE significantly decreased IL-8, caspase-3, caspase-8 and caspase-9 mRNA levels and significantly increased IL-10 and TGF-ß1 mRNA levels in the liver of fish fed high lipid diets. In conclusion, high lipid diets supplemented with LBE improved growth performance, feed utilization and liver health in hybrid groupers by increasing hepatic antioxidant enzymes activity and its genes expression, as well as inhibition of hepatic inflammatory response and apoptosis.