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The current study was aimed to examine the effect of grape seed proanthocyanidin extract (GSPE) on regulating lipid metabolism of American eels. A total of six cement tanks of fish were randomly divided into a control group fed with a commercial diet and a GSPE group fed with a commercial diet supplemented 400 mg/kg GSPE. There were three replicates in each group. Results suggested that GSPE could decrease the levels of total cholesterol, triglycerides, and low-density lipoprotein cholesterol, and increase the high-density lipoprotein cholesterol level in serum. GSPE might regulate lipid metabolism through upregulating linoleic acid metabolism and arachidonic acid metabolism along with downregulating metabolisms of phenylalanine, tyrosine, and tryptophan biosynthesis and valine, leucine, and isoleucine biosynthesis.

The present study was conducted to evaluate the effects of dietary Macleaya cordata extract (MCE) supplementation on growth performance and intestinal health of American eels (Anguilla rostrata) farmed in intensive system. A total of six cement tanks of fish were randomly divided into a control group fed a commercial diet and an MCE group fed the commercial diet with 100 mg/kg MCE, respectively. There were three replicates in each group. The results suggested that 100 mg/kg MCE could improve the growth performance and intestinal health of the American eels by strengthening the barrier function and antioxidative ability in the intestine and beneficially modulating intestinal microbiota with the higher relative abundance and more species of the potential probiotics and the lower relative abundance of potentially pathogenic bacteria.

This study determined whether accumulated liver and visceral lipid in yellow perch can be alleviated by feeding an appropriate starch source. We compared the growth performance, nutritional composition and health of yellow perch fed a control diet (no added starch) and three diets with corn, potato or wheat starch (200 g/kg diet) to replace an equal proportion of fishmeal in the control diet. Dietary starch led to increased bulk density, hardness and gelatinization levels of feed pellets compared with the control diet. At the end of an 8‐week feeding, all fish fed the test diets had similar growth rates (p > .05). However, the wheat starch diet resulted in significantly enlarged livers and increased accumulation of lipid in the liver, viscera and whole body (p < .05). This diet also caused significantly higher levels of fasting glucose, aspartate aminotransferase and alkaline phosphatase activities in serum than the control diet. Liver cell diameters were larger, and Kupffer cell numbers were lower in the fish fed the wheat starch than those fed the control diet. Potato or corn starch had less impact on fish health and is considered to be an appropriate carbohydrate sources for yellow perch under the current testing conditions.

Two 3‐week growth trials were performed to determine the optimum feeding rate of juvenile lake sturgeon (Acipenser fulvescens) fed with a semi‐purified dry diet (protein, 440 g; lipid, 130 g/kg) at different feeding rates: 5, 10, 20, 30, and 40 g/kg body weight per day (BW/.d‐1), for 36 g‐sized fish; and 2.5, 5, 10, 20, and 30 g/kg BW/.d‐1, for 80 g sized fish. Feeding rates significantly influenced growth performances, feed conversion ratio, wholebody lipid and moisture contents, energy and protein retention, and fasted blood glucose levels (p

The present trial was conducted to investigate the effects of bile acids on growth performance, digestive enzymes activities, serum biochemical parameters and intestinal microbiota on growth of retarded European eels (Anguilla anguilla) cultured in cement tanks. The trial fish with similar body size (about 140g per fish) cultured in nine cement tanks (fish weight, 681.7±22.7 kg per tank) were randomly divided into three groups and fed diets with bile acids supplementation at a level of 0, 500, and 1000 mg/kg, respectively. The trial period was 15 weeks. Dietary bile acids supplementation improved weight gain rate, feed intake, and activities of protease and lipase in intestine. There were also increases in levels of immunoglobulin and complements as well as activities of alkaline phosphatase (only in 1000 mg/kg bile acids group), acid phosphatase and lysozyme in serum. The levels of blood urea nitrogen, total cholesterol, triglyceride, low density lipoprotein cholesterol and activities of glutamic-oxalacetic transaminase and glutamic-pyruvic transaminase were decreased by dietary bile acids supplementation. There were no significant differences in growth performance or serum biochemical parameters except the lysozyme activity between two bile acids supplementation groups. Dietary bile acids supplementation could increase richness and decrease diversity of the intestinal microbiota with different enriched bacteria at genus level. In conclusion, this study demonstrated that 500 mg/kg bile acids supplementation in the diet of growth retarded European eels cultured in cement tanks could promote growth performance, improve some digestive enzymes activities, and beneficially regulate serum biochemical parameters and intestinal microbiota.

Autochthonous probiotics were proposed to have a higher capacity to compete with resident pathogens and were also more prone to dominate and persist over other potentially pathogenic microbes. Therefore, the aim of this study was conducted to investigate the potential autochthonous microbiota by revealing the differences in the intestinal microbiota composition of European eels (Anguilla anguilla) with different growth rates. The differences of diversity, an abundance of the intestinal microbiota, and compositions of all the libraries were identified. Moreover, the composition of the intestinal microbiota of European eels was affected by the growth rates. The dominant phylum of the intestinal microbiota of fast growth eels was Fusobacteria, while Spirochaetes was the dominant phylum of the intestinal microbiota of slow growth and medium growth eels. Cetobacterium was identified as the predominant genera of the intestinal microbiota of fast growth eels; there was a significant difference in this genus between fast growth eels and slow growth eels. Although the relative abundances of Plesiomonas, Turicibacter, Nitrospira, and Lachnospiraceae bacterium NK4A136 group were also increased with the growth rates, only Cetobacterium seemed to have great potential as the probiotics to European eels.

Aeromonas spp. are prevalent pathogens in farmed eel, which induce highly infectious diseases, such as hemorrhagic septicemia and gill-rot disease. Research on the application of ethanol and water extracts from traditional Chinese herbs in controlling the diseases has increased. However, the exact antibacterial components in majority of these herbs were not well-studied. Four fractions or components were isolated from Terminalia chebula Retz. ethanol extract in our previous study. In the present study, their antibacterial effects on A. hydrophila and A. veronii were assessed using microcalorimetry. The results showed that component III (a single chemical constituent, gallic acid) had the strongest antibacterial effect compared with three other fractions. The inhibitory effect was enhanced as the concentration of component III increased, and the minimum inhibitory concentrations of component III to A. hydrophila and A. veronii were found to be 0.56 mg/ml and 0.74 mg/ml respectively. This is the first study in which the antibacterial component of T. chebula extract on aquatic bacteria growth was screened and determined by microcalorimetry.

This trial was conducted to investigate the effects of supplementary surfactin on growth performance, intestinal digestive enzymes activities and some serum biochemical parameters of tilapia (Oreochromis niloticus) fingerlings. Three hundred and twenty fish were randomly divided into four treatment groups with four replicates in each group and 20 fish in each replicate. The dietary surfactin levels of four treatment groups were 0 (control group), 50, 100 and 200 mg/kg. The trial period was 7 weeks. Compared with the control group, final body weight, daily feed intake, weight gain rate, feed conversion ratio and protein efficiency ratio were improved significantly by surfactin supplementation (p 0.05). The activities of protease and lipase in intestine of surfactin supplementation groups were significantly higher than those of the control group (p 0.05). The activities of aspartate aminotransferase and alanine aminotransferase were decreased significantly by dietary surfactin supplementation (p

A 70 day trial was conducted to investigate the effects of surfactin on growth, digestive enzyme activity, and antioxidant potential in the intestine of growth retarded marbled eels (Anguilla marmorata) at the elver stage. Six hundred and forty marbled eels at elver stage were randomly divided into four treatment groups with four replicates per group, and 40 fish per replicate. The dietary surfactin level of the four experimental diets was 0, 25, 50, and 100 mg/kg, respectively. Final body weight, weight gain rate, survival rate, protease activity in the intestine, malondialdehyde level, total antioxidation capacity level, and activities of superoxide dismutase, and glutathione peroxidase in the intestine of fish, increased significantly with surfactin supplementation, and feed conversion rates improved significantly (P0.05). Results demonstrated that dietary surfactin supplementation could improve growth performance, some digestive enzyme activities, and antioxidant potential, in the intestine of growth retarded marbled eel at elver stage. Surfactin could be used as a dietary growth promoter for growth retarded eels.

A 70 day trial was conducted to investigate the effects of surfactin on growth, digestive enzyme activity, and antioxidant potential in the intestine of growth retarded marbled eels (Anguilla marmorata) at the elver stage. Six hundred and forty marbled eels at elver stage were randomly divided into four treatment groups with four replicates per group, and 40 fish per replicate. The dietary surfactin level of the four experimental diets was 0, 25, 50, and 100 mg/kg, respectively. Final body weight, weight gain rate, survival rate, protease activity in the intestine, malondialdehyde level, total antioxidation capacity level, and activities of superoxide dismutase, and glutathione peroxidase in the intestine of fish, increased significantly with surfactin supplementation, and feed conversion rates improved significantly (P0.05). Results demonstrated that dietary surfactin supplementation could improve growth performance, some digestive enzyme activities, and antioxidant potential, in the intestine of growth retarded marbled eel at elver stage. Surfactin could be used as a dietary growth promoter for growth retarded eels.

The effect of dietary administration of probiotic Lactococcus lactis MM1 for 60 d on the autochthonous microbiota in the foregut, midgut and hindgut of juvenile grouper, Epinephelus coioides, was evaluated using polymerase chain reaction-denaturing gradient gel electrophoresis (DGGE). Samples collected from the probiotic and control groups showed different DGGE patterns, while 11 common bands presented in both groups. The similarity dendrogram revealed three different clusters depending on the three sections of the gastrointestinal (GI) tract, and the probiotic triplicates in each GI section were generally clustered into one group distinctly different from the corresponding control triplicates. Increased species richness and Shannon index were observed in the foregut, midgut, and hindgut samples in the probiotic group compared with the control group, which suggested that probiotic L. lactis MM1 could improve the autochthonous microbial diversity along the GI tract of E. coioides. The growth of many potentially beneficial and unidentified bacteria was stimulated by the probiotic, whereas the growth of some potential harmful species, like Staphylococcus saprophyticus, was depressed.

A precision-fed assay was conducted to determine true metabolisable energy and true amino acid digestibility in Chinese quality protein maize (QPM) compared with normal maize (NM). Thirty adult roosters, kept in individual cages, were made to fast for 48h and then tub-fed 50g QPM or NM per bird and their excreta was colleted for the subsequent 48h. Additional fifteen roosters were made to fast in order to estimate endogenous losses of energy and amino acids (AA) in excreta. Gross energy of the two types of maize were similar; the lysine content in NM and QPM were 0.27% and 0.41% (DM basis), respectively. True metabolisable energy (TME) and true metabolisable energy nitrogen corrected (TMEn) values of QPM and NM were not significantly different (P>0.05). Digestibility of some AA, including lysine and methionine, in QPM were higher than those in NM (P

The chemical composition, amino acid content, true amino acid digestibility and TMEn for poultry of adult Chinese grasshopper (Acrida cinerea (Thunberg)) were investigated. The adult insect mainly contained: crude protein (CP) 654.2 g kg−1; fat 83.0 g kg−1 and chitin 87.3 g kg−1 on dry matter basis. The content of amino acids compared well with fish meal; the methionine, cystine and lysine concentrations in the grasshopper meal were 17.0, 6.9 and 37.9 g kg−1 on dry matter basis. The coefficient of total tract true amino acid digestibility of methionine, cystine, and lysine in the grasshopper meal were 0.97, 0.84 and 0.95 determined in cecectomized roosters, respectively. The nitrogen-corrected true metabolizable energy (TMEn) of the grasshopper meal was 11.34 MJ/kg determined in cecectomized roosters. When maize–insect–soybean meal diets were formulated on an equal CP and TMEn basis, up to 150 g kg−1 grasshopper meal could replace control diet without any adverse affects on broiler weight gain, feed intake, or gain:feed ratio from 8 to 20 days posthatching. The fatty acid analysis showed polyunsaturated fatty acids of the grasshopper meal to be present in high quantities, and the total content of oleic, linoleic and linolenic acids was 0.8449 of total fatty acids. The results indicated that the insect could be an acceptable raw material for feed and food.

The proximate analysis, amino acid content and true amino acid digestibility and TMEn for poultry of adult Field crickets Gryllus testaceus Walker, were investigated. The insect was also used as partial replacement of protein supplements in the broiler diet on an equal CP percentage and TMEn basis. The results indicated that the adult insect contained: crude protein 58.3%; fat 10.3%, chitin 8.7% and ash 2.96% on dry matter basis, respectively. The total amounts of methionine, cystine and lysine in the Field crickets were 1.93%, 1.01% and 4.79%, respectively, and their true digestibility coefficients, determined in cecectomized roosters, were 94.1%, 85% and 96%, respectively. The TMEn of this insect meal was 2,960 kcal/kg determined in cecectomized roosters. When corn- soybean meal diets were formulated on an equal CP percentage and TMEn basis, up to 15% Field cricket could replace control diet without any adverse affects on broiler weight gain, feed intake or gain:feed ratio from 8 to 20 d posthatching. (Asian-Aust. J. Anim. Sci. 2005. Vol 18, No. 5 : 667-670)

The present study was performed with tilapia (Oreochromis niloticus) to evaluate the effects of diet supplementation with grape seed proanthocyanidins (GSPs) on fish growth performance, some serum parameters and body composition. Three hundred tilapia fingerlings with the initial average body weight of 9.50±1.25 g were randomly divided into five treatment groups with four replicates in each group and 15 fish in each replicate. The dietary GSPs levels of five treatment groups were 0 (control group), 200, 400, 600, and 800 mg/kg, respectively. The trial period was 49 days. Growth performance parameters were significantly improved by GSPs supplementation (P0.05). Serum parameter results showed that activities of aminotransferase aspartate in 200 and 400 mg/kg GSPs groups and alanine aminotransferase in 400 mg/kg GSPs group were lowered significantly (P0.05). The results indicated that dietary 200 mg/kg GSPs could exert beneficial effects on growth and body composition of tilapia fingerlings, and ameliorate serum biochemistry parameters related to health status.

This trial was conducted to investigate the effects of Quercetin on the growth performance, activities of digestive enzymes, and antioxidant potential in the hepatopancreas of tilapia. Four hundred tilapia (Oreochromis niloticus), were randomly divided into five treatment groups with four replicates in each group/ 20 fish per replicate. The dietary Quercetin levels of the five treatment groups were 0, 200, 400, 800, and 1600 mg/kg, respectively. The trial period was 49 days. Rates of weight gain, special growth, feed conversion, and protein efficiency ratio of the Quercetin diet groups improved significantly (P0.05). The activity of protease, lipase, and amylase, in the stomach and intestine significantly increased when the dietary Quercetin level was above 400 mg/kg. The malondialdehyde level, and total antioxidant capacity in the hepatopancreas of Quercetin diet groups decreased significantly while catalase activity of Quercetin diet groups (apart from the group fed 1600 mg/kg Quercetin) increased significantly (P