Heizhao Lin

The effects of dietary soybean isoflavones on growth, innate immune responses, hepatic antioxidant abilities and disease resistance of juvenile golden pompano Trachinotus ovatus.

The present study was conducted to investigate the effects of dietary soybean isoflavones (SI) supplementation on growth performance, innate immune responses, hepatic antioxidant abilities, heat shock protein 70 (HSP70) gene expression and resistance to the pathogen Vibrio harveyi in Trachinotus ovatus. A basal diet was supplemented with SI at 0, 10, 20, 40, 60, 80 mg kg(-1) feed for 8 weeks. Significantly maximum weight gain (WG) and specific growth rate (SGR) were observed in treatment with 40 mg kg(-1) SI supplement (P < 0.05). Feed conversion ratio (FCR), feeding rate (FR) and survival rate were not significantly different among treatments. Fish fed a diet with 40 mg kg(-1) SI showed significant increase in plasma total protein content, complement 3 content, lysozyme activity as well as respiratory burst activity, but decrease in alanine aminotransferase and aspartate aminotransferase activities (P < 0.05). Increased plasma alkaline phosphatase activity, hepatic total antioxidative capacity, catalase activity and superoxide dismutase activity were also noticed in fish fed SI at 40 or 60 mg kg(-1) (P < 0.05). On the contrary, the lowest hepatic malondialdehyde (MDA) content was observed in fish fed SI at 40 mg kg(-1) (P < 0.05). Compared with the control, the relative level of HSP70 mRNA in fish fed SI at 40-80 mg kg(-1) were significantly increased, respectively (P < 0.05). After challenge with V. harveyi, significant higher post-challenge survival was observed in fish fed diets with 40-80 mg kg(-1) SI supplement than that in control group (P < 0.05). These results indicated that dietary intake containing SI could enhance the immune ability of fish and improve its resistance to infection by V. harveyi. Especially supplementation with 40 mg kg(-1) SI to the fish for 8 weeks showed remarkable improvement in the growth, non-specific immune responses, hepatic antioxidant abilities and HSP70 gene expression.

Dietary values of astaxanthin and canthaxanthin in Penaeus monodon in the presence and absence of cholesterol supplementation: effect on growth, nutrient digestibility and tissue carotenoid composition

Penaeus monodon (mean initial wet weight 1·19 (SE 0·01) g) were fed seven diets in triplicate: a control diet (D1) without carotenoids; three diets formulated to supply 0·1 % astaxanthin alone (D2), 0·2 % astaxanthin alone (D3), and a combination of 0·1 % astaxanthin and 1 % cholesterol (D4); three diets with 0·07 % canthaxanthin alone (D5), 0·13 % canthaxanthin alone (D6), and a combination of 0·07 % canthaxanthin and 1 % cholesterol (D7). Weight gain (WG, %), specific growth rate (SGR, %/d) and survival were chosen as parameters of shrimp growth performance. Total antioxidant status (TAS), superoxide dismutase (SOD), aspartate aminotransferase (AST) and alanine aminotransferase (ALT) were chosen as indices of shrimp plasma antioxidant capacity. Meanwhile, digestibility, retention efficiency and tissue carotenoids were also investigated to determine the additive effect of cholesterol on the efficiency of astaxanthin and canthaxanthin. After 74 d rearing, WG and SGR of shrimp fed D2-D4 and D7 were higher than those of shrimp fed D1 (P < 0·05). Shrimp fed D4 had the highest survival. The apparent digestibility coefficients (ADC) of astaxanthin in D2-D4 were higher than those of canthaxanthin in D5-D7 (P < 0·05). Although ADC of astaxanthin were quite high (>98 %) in D2-D4 and no differences were found among them (P>0·05), the carotenoid retention efficiencies in the whole body, muscle and shell (D2-D3 treatments) were considerably low; however, cholesterol supplementation significantly improved the carotenoid retention efficiencies in the whole body, muscle and shell (D4 treatment). Accordingly, the addition of cholesterol also significantly enhanced the carotenoid contents of tissues. Shrimp fed supplemented carotenoid diets (D2-D7) had higher TAS and lower SOD, ALT and AST than shrimp fed D1 (P < 0·05). A low dissolved oxygen stress test was conducted for 7 d after the rearing trial and shrimp survival was also compared among the treatments. The survival of shrimp fed the diets supplemented with astaxanthin or canthaxanthin was higher than that of shrimp fed D1 during the stress test (P < 0·05). In conclusion, all data suggested that astaxanthin was better than canthaxanthin as the dietary carotenoid source in the commercial diet of P. monodon, and the supplement of cholesterol could positively enhance the efficiency of astaxanthin and canthaxanthin.

Dietary supplementation of honeysuckle improves the growth, survival and immunity of Penaeus monodon

Two trials were conducted to determine the effects of honeysuckle on shrimp, Penaeus monodon, first on growth performance, secondly on the immune response of shrimp. In trial 1, shrimp (mean initial wet weight about 3.02 g) were fed with five diets containing 0% (basal diet), 0.1%, 0.2%, 0.4% and 0.8% honeysuckle in triplicate for 60 days. Growth performance (final body wet weight, FBW; weight gain, WG; biomass gain, BG) of shrimp fed honeysuckle diets were higher (P < 0.05) than that of shrimp fed the basal diet, shrimp fed 0.4% honeysuckle diet showed the highest value of growth performance. Shrimp fed 0.2% honeysuckle diet showed highest value of survival. The total antioxidant status (TAS) and glutathione peroxidase (GSH-Px) activity of shrimp fed 0.2%, 0.4% and 0.8% honeysuckle diets were higher (P < 0.05) than those of shrimp fed basal and 0.1% honeysuckle diets. Hepatopancreas malondialdehyde (MDA) of shrimp fed honeysuckle diets were lower (P < 0.05) than that of shrimp fed the basal diet. Total haemocyte count of shrimp fed the basal diet was lower (P < 0.05) than that of shrimp fed honeysuckle diets. Haemolymph clotting time of shrimp had the opposite trend with the total haemocyte count of shrimp. In trial 2, the shrimp were exposed to air during a simulated live transportation for 36 h after the rearing trial. The antioxidant responses were characterized by lower TAS and higher antioxidant enzyme activities (superoxide dismutase: SOD, GSH-Px) and higher oxidative stress level (MDA) in the hepatopancreas compared to levels found in trial 1. No mortalities were observed in any diet groups after 36 h of simulated live transportation. The glutathione (GSH) content and TAS of shrimp fed 0.2%, 0.4% and 0.8% honeysuckle diets were higher (P < 0.05) than those of shrimp fed the basal and 0.1% honeysuckle diets. The SOD activity of shrimp fed the basal diet was higher (P < 0.05) than that of shrimp fed honeysuckle diets. The GSH-Px activity of shrimp fed the basal diet was lower (P < 0.05) than that of shrimp fed 0.2%, 0.4% and 0.8% honeysuckle diets but without significant difference (P > 0.05) with shrimp fed 0.1% honeysuckle diet. Moreover, the oxidative stress level (MDA) recorded in the hepatopancreas with shrimp submitted to the honeysuckle diets were lower. In conclusion, results suggested that dietary intake containing honeysuckle could enhance the growth performance of P. monodon and improve its resistance to air exposure during simulated live transportation. Considering the effect of honeysuckle on both growth performance and survival of P. monodon, the level of honeysuckle supplemented in the diet should be between 0.2% and 0.4%.

Effects of dietary dandelion extracts on growth performance, body composition, plasma biochemical parameters, immune responses and disease resistance of juvenile golden pompano Trachinotus ovatus

Abstract The present study was conducted to investigate the effects of dietary dandelion extracts (DE) supplementation on growth performance, feed utilization, body composition, plasma biochemical indices, immune responses, hepatic antioxidant abilities, and resistance to the pathogen Vibrio harveyi in Trachinotus ovatus. A basal diet supplemented with DE at 0, 0.50, 1.00, 2.00, 4.00 and 10.00 g kg−1 were fed to golden pompano for 8 weeks. The study indicated that dietary supplementation with DE could significantly improve final body weight (FBW), weight gain rate (WGR), specific growth rate (SGR), feed efficiency ratio (FER), feed intake (FI), protein efficiency ratio (PER) and protein deposit rate (PDR) (P < 0.05). The highest FBW, WGR, SGR, FI and PDR were observed in fish fed 1.00 g kg−1 dietary DE (P < 0.05). The highest FER and PER were recorded at 0.50 g kg−1 dietary DE (P < 0.05). Condition factor, viscerosomatic index, hepatosomatic index and survival were not significantly different among all groups. Fish fed 1.00 g kg−1 dietary DE showed significant increase in plasma total protein, complement 4 content and alkaline phosphatase, lysozyme, glutathione reductase (GSR) activity, but significant decrease in triglyceride, low density lipoprotein cholesterol, malondialdehyde (MDA) content and aspartate aminotransferase activities compared to the control group (P < 0.05). Hepatic antioxidant enzymes (SOD, T‐AOC, CAT, GSH‐Px, GSR) significantly increased whereas MDA content significantly decreased in fish fed 1.00 g kg−1 DE supplement (P < 0.05). After challenge with Vibrio harveyi, significant higher post‐challenge survival was observed in fish fed DE supplement (P < 0.05). These results indicated that golden pompano fed a diet supplemented with DE (especially at 1.00 g kg−1 of fed supplement) could significantly promote its growth performance, feed utilization, body protein deposit, immune ability, hepatic and plasma antioxidative enzyme activities and improve its resistance to infection by Vibrio harveyi. HighlightsDietary supplementation with dandelion extracts significantly improved growth performance in golden pompano.Dietary supplementation with dandelion extracts significantly enhanced immunity in golden pompano.Dietary supplementation with dandelion extracts significantly increased survival after Vibrio harveyi challenge.

Effects of dietary ginkgo biloba leaf extract on growth performance, plasma biochemical parameters, fish composition, immune responses, liver histology, and immune and apoptosis-related genes expression of hybrid grouper (Epinephelus lanceolatus♂ × Epinephelus fuscoguttatus♀) fed high lipid diets

ABSTRACT For thousands of years, leaves from the Ginkgo biloba tree have been a common treatment in Chinese medicine. The present study was conducted to investigate the effects of dietary ginkgo biloba leaf extract (GBE) supplementation on growth performance, plasma biochemical parameters, fish composition, immune responses, liver histology, and immune and apoptosis‐related genes expression of hybrid grouper (Epinephelus lanceolatus♂ × Epinephelus fuscoguttatus♀) fed high lipid diets. A basal diet supplemented with GBE at 0, 0.50, 1.00, 2.00, 4.00 and 10.00 g kg−1 was fed to hybrid grouper for 8 weeks. The study indicated that dietary GBE did not improve growth performance and feed utilization but it reduced intraperitoneal fat rate. There were no significant differences in condition factor, viscerosomatic index, hepatosomatic index, spleen index, relative gut length, food intake, protein deposit rate and survival among all groups (P > 0.05). Dietary supplementation with 0.50–4.00 g GBE kg−1 diets effectively increased plasma HDL content and decreased plasma GLU, LDL and TG content in fish. Furthermore, dietary GBE had a significant effect on moisture, crude protein and lipid in the liver, and protein in the whole body of fish (P < 0.05). Dietary supplementation with 0.50–1.00 g GBE kg−1 diets effectively decreased occurrence rates of the hepatocyte swelling, hepatocyte vacuolization, and nuclei shifting to the cellular periphery cytoplasmic vacuolization, meanwhile hepatic antioxidant enzymes (SOD, CAT and T‐AOC) activities significantly increased whereas MDA content significantly decreased in fish fed diets supplemented with GBE (P < 0.05). Moreover, dietary GBE up‐regulated the expression of antioxidant genes (CAT, GPx and GR), immune‐related genes (MHC2 and TLR3) and anti‐inflammatory cytokines (IL‐10 and TGF‐&bgr;1), while dietary supplementation with 0.50–4.00 g GBE kg−1 diets down‐regulated apoptosis‐related genes (p53, caspase‐9, caspase‐8 and caspase‐3) expression in the head kidney of hybrid grouper. These results indicated that hybrid grouper fed diets supplemented with GBE did not improve growth performance and feed utilization but it had hypolipidemic effects, improved hepatic antioxidant status, maintained normal liver histology and preserved liver function, increased immune‐related genes expression and decreased apoptosis‐related genes expression in the head kidney of hybrid grouper. HighlightsDietary ginkgo biloba leaf extract (GBE) had hypolipidemic effects in hybrid grouper fed high lipid diets.Dietary GBE improved hepatic antioxidant ability and maintain normal liver histology.Dietary GBE increased immune‐related genes expression and decrease apoptosis‐related genes expression.

Effects of dietary hawthorn extract on growth performance, immune responses, growth- and immune-related genes expression of juvenile golden pompano (Trachinotus ovatus) and its susceptibility to Vibrio harveyi infection

ABSTRACT The present study was conducted to investigate the effects of dietary hawthorn extract (HTE) supplementation on growth performance, immune responses, hepatic antioxidant abilities, growth‐ and immune‐related and heat shock protein genes expression and resistance to the pathogen Vibrio harveyi in Trachinotus ovatus. A basal diet supplemented with HTE at 0 (Diet 1), 0.50 (Diet 2), 1.00 (Diet 3), 2.00 (Diet 4), 4.00 (Diet 5) and 10.00 (Diet 6) g kg−1 were fed to golden pompano for 8 weeks. The highest final body weight, weight gain rate, specific growth rate, feed efficiency ratio and protein efficiency rate were observed in fish fed Diet 2 (P < 0.05). Dietary HTE significantly increased plasma complement 3, complement 4 and immunoglobulin M content (P < 0.05). Hepatic antioxidant enzymes (SOD, T‐AOC, CAT, GPx, GR) significantly increased (P < 0.05), whereas MDA content decreased first and then increased in fish fed HTE supplement. After challenge with Vibrio harveyi, significant higher post‐challenge survival was observed in fish fed Diet 2 and Diet 3 than the control group (P < 0.05). Transcription levels of growth‐related genes (IGF‐I and IGF‐II) were significantly up‐regulated in fish fed HTE supplement (P < 0.05), whereas HSP70 and HSP90 mRNA levels were significantly down‐regulated (P < 0.05). With respect to immune‐related genes, such as tumour necrosis factor‐alpha (TNF‐&agr;), interleukin‐8 (IL‐8) and inhibitor protein &kgr;B&agr; (I&kgr;B‐&agr;), upregulation was observed in the liver of fish fed with the diet supplemented with HTE. In contrast, the expression of antioxidant enzyme genes (CAT, GPx, MnSOD and Keap1) and cytokines (IL‐10, TGF‐&bgr;1 and TOR) was downregulated. These results indicated that golden pompano fed a diet supplemented with 0.50 g kg−1 HTE could significantly promote growth performance and growth‐related genes expression, strengthen immunity, and improve hepatic antioxidative abilities and resistance to Vibrio harveyi infection. HighlightsDietary HTE improved growth performance and immunity in golden pompano.Dietary HTE significantly increased survival after Vibrio harveyi challenge.

Effects of graded replacement of fish meal by fish protein hydrolysate on growth performance of early post-larval Pacific white shrimp (Litopenaeus vannamei, Boone)

Five dietary concentrations of fish protein hydrolysate (0, 9, 18, 27 and 36%) were included in five isonitrogenous diets (H0, H9, H18, H27 and H36) replacing fish meal by 0, 15, 30, 46 and 61% and offered to triplicate groups of early white shrimp post-larvae (mean initial wet weight 2 mg). After the 30-day feeding trial, the highest values of survival were obtained with shrimp fed diets H18 and H27. Final mean body wet weights (FBW, mg) of shrimp fed diets H9, H18, H27 and H36 were significantly higher than that of shrimp fed diet H0. Biomass gain (BG, g) of shrimp fed diets H18 and H27 were significantly higher than that of shrimp fed diets H0, H9 and H36. Specific growth rate (SGR, % day−1) showed the same pattern as FBW. Weight gain (WG, %) of shrimp fed diets H18 and H27 were significantly higher than that of shrimp fed diets H0 and H9. The trypsin activities of shrimp fed diets H9, H18, H27 and H36 were significantly higher than that of shrimp fed diet H0. Second-degree polynomial regression analysis on BG and WG indicated the appropriate supplement of fish protein hydrolysate in the diet of early white shrimp post-larvae should be between 21.22 and 26.35% of diet.

Excess dietary cholesterol may have an adverse effect on growth performance of early post-larval Litopenaeus vannamei

One experiment was conducted to determine the nutritive value of cholesterol for post-larval shrimp, Litopenaeus vannamei. Four isoenergetic and isonitrogenous diets supplemented with four levels of cholesterol (D1, D2, D3 and D4 with 0, 0.5%, 1% and 2% cholesterol, respectively) were fed to triplicate groups of L. vannamei shrimp (mean initial wet weight 0.8 mg) for 27 days. After the trial, shrimp fed the D1 diet had the best growth performance (final body weights: FBW; weight gain: WG; specific growth rate: SGR), while there was no significant difference between diet treatments with respect to survival. The whole body crude protein level in the shrimp decreased with the increase in dietary cholesterol levels, while the whole body crude lipid level in shrimps in the D4 diet treatment was significantly higher (P < 0.05) than in other diet treatments. Dietary analysis indicated that the D1 diet contained 0.92% cholesterol prior to supplementation, which may have satisfied the dietary cholesterol requirement of post-larval L. vannamei; excess dietary cholesterol may thus lead to adverse effects on the growth performance of post-larval shrimp.

Effects of dietary Spirulina platensis on growth performance, hematological and serum biochemical parameters, hepatic antioxidant status, immune responses and disease resistance of Coral trout Plectropomus leopardus (Lacepede, 1802)

ABSTRACT The present study investigated the effects of dietary Spirulina platensis supplementation on growth performance, hematological and serum biochemical parameters, hepatic antioxidant status, immune responses and resistance to the pathogen infection in Coral trout Plectropomus leopardus. The fish were fed for 8‐week with diets containing different levels of S. platensis: 0% (C), 2% (SP2), 4% (SP4), 6% (SP6), 8% (SP8) and 10% (SP10) as treatment groups, followed by a Vibrio harveyi infection test for 14d. The study indicated that dietary supplementation with Spirulina platensis could significantly improve growth performance, and the highest weight gain rate (WGR) and specific growth rate (SGR) were observed in group SP10 (P<.05). Red cell count (RBC), white cell count (WBC), hemoglobin (Hb) and total antioxidant capacity (T‐AOC) in the S. platensis supplemented groups were significantly higher than those of group C (P<.05). However, the levels of cholesterol, triglyceride and malondialdehyde (MDA) contents, and superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPX) activities decreased with the increasing of dietary S. platensis levels. Compared with group C, the lysozyme (LYZ) and respiratory burst activities (RBA), and immunoglobulin (Ig) and complement contents in group SP4, SP6, SP8 and SP10 increased significantly than those of group C respectively (P<.05). After challenge with V. harveyi, the survival rate in group SP4, SP6, SP8 and SP10 was significantly higher than that of group C, and the highest survival rate was in group SP10 (P<.05). These results indicated that P. leopardus fed a diet supplemented with S. platensis (especially at 10%) could significantly promote its growth performance, improve its hepatic antioxidant status, and enhance its immune ability and resistance to V. harveyi infection. HIGHLIGHTSPlectropomus leopardus diets were supplemented with Spirulina platensis.Dietary S. platensis had positive effects on growth, hematological parameters, and immune responses of P. leopardus.S. platensis both activate and suppress different hepatic antioxidant parameters.S. platensis could be considered as potent preventive antigens to Vibrio harveyi for P. leopardus.

Effects of dietary dandelion extract on intestinal morphology, antioxidant status, immune function and physical barrier function of juvenile golden pompano Trachinotus ovatus

ABSTRACT Intestinal morphology, antioxidant status, immune function and tight junction proteins mRNA expression were examined in golden pompano (Trachinotus ovatus) that fed respectively six diets containing dandelion extracts (DE) at 0, 0.5, 1, 2, 4 and 10gkg−1 after 8 weeks feeding. The study indicated that dietary DE significantly improved intestinal antioxidant abilities by increasing SOD, CAT, T‐AOC activities and up‐regulating intestinal cat, gpx mRNA levels, but by decreasing MDA content and down‐regulating intestinal keap1 mRNA levels in golden pompano. Meanwhile, dietary DE improved intestinal morphology, suggesting that enhances intestinal digestion and absorption, by increasing muscle thickness, villus length, villus width and villus number in the foregut and hindgut; as well as villus number, villus width and muscle thickness in the midgut (P<.05). Dietary DE enhanced intestinal barrier function by increasing intestinal zo‐1 and occludin mRNA levels, but by decreasing the mRNA levels of claudin‐12 and claudin‐15. Furthermore, dietary DE improved intestinal immunity via increasing goblet cells numbers and regulating expression of immune‐related genes. In conclusion, dietary DE supplementation promoted intestine health by improving intestine morphology, immunity, antioxidant abilities and intestinal barrier in golden pompano. HIGHLIGHTSDietary dandelion extracts (DE) enhanced intestinal digestion and absorption by improving intestinal morphology of golden pompano.DE regulated the tight junction proteins mRNA levels, suggesting improved intestinal physical barrier.DE improved intestinal antioxidant abilities by increasing antioxidant enzyme activities.