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A 5 × 3 factorial growth trial was conducted to evaluate optimal dietary protein and lipid levels (dietary protein level, DP; dietary lipid level, DL) for juvenile Sillago sihama (S. sihama) (2.0 ± 0.02 g, initial weight). Fish were fed 15 diets containing 5 DPs (350, 400, 450, 500 and 550 g/kg) and 3 DLs (60, 90 and 120 g/kg) for 8 weeks. The interaction between proteins and lipids significantly influenced the feed conversion ratio, condition factor, body composition, antioxidant indices and lipase activity (p <.05). DP 450 g/kg showed the highest average final body weight. DPs 500 and 550 g/kg significantly decreased the protein efficiency ratio (p <.05). DL 120 g/kg showed the highest percentage weight gain. The low feed conversion ratio was found in diets P45L12, P55L9 and P55L12. Diet P45L12 showed high superoxide dismutase activities. DP 450 g/kg showed the lowest average malondialdehyde content. Lipase activity was increased by increasing DP (p <.05) with a fall at DP 550 g/kg. Under the present experimental conditions, the optimal DP for S. sihama was 450 g/kg under the DL 120 g/kg. [ABSTRACT FROM AUTHOR]

Abstract: A 56‐day growth trial was performed to dietary vitamin A (VA) requirement of Sillago sihama Forsskál (S. sihama) with an initial weight of 2.05 ± 0.15 g (mean ± SE). Quadruplicate groups of 40 juveniles per tank were fed with diets containing 362, 751, 1,141, 2,202, 4,335, 8,230, and 18,932 IU VA/kg diet respectively. Haemorrhages, erosion, greater mortality, and sluggish movement were found in fish of the control, whereas fish fed the 18,932 IU VA/kg diet appeared poor appetite. The weight gain rate (WG), specific growth rate (SGR) were highest at the level of 2,202 IU VA/kg diet, and the feed conversion ratio (FCR) showed the minimum at the same level. Compared with the control, groups 1,141–18,932 IU VA/kg showed significantly higher hepatic lysozyme (LZM) activity. Superoxide dismutase (SOD) at level of 751–4,335 IU VA/kg increased significantly than it in the control and reached a plateau after 4,335 IU VA/kg. Alkaline phosphatase (AKP) decreased significantly at level of 8,230–18,932 IU VA/kg diet than it in the control. Total antioxidation capability (T‐AOC), catalase (CAT), and glutathione peroxidase (GSH‐Px) in liver tended to increase and kept stable at level of 8,230 and 18,932 IU VA/kg diet. Fish fed 2,202 IU VA/kg diet showed significantly higher intestinal Na+‐K+ ATPase activity than it in other groups. The broken‐line model based on WG and maximum liver VA concentration indicated that the VA requirement was of 2,516 and 4,334 IU VA/kg respectively. [ABSTRACT FROM AUTHOR]

Abstract: A 50‐day feeding trial was conducted for juvenile pearl gentian grouper (Epinephelus lanceolatus ♂ × Epinephelus fuscoguttatus ♀) to determine the optimal amount of Tenebrio molitor meal (TM) that could replace fishmeal (FM) in feeds without reducing growth performance, antioxidant enzyme activities and resistance. Six isonitrogenous and isolipidic diets were formulated with TM replacing 0% (T0), 6.25% (T6), 12.5% (T12), 18.75% (T18), 25% (T25), 31.25% (T31) FM respectively. Each diet was randomly divided into triplicate groups with 30 juveniles (initial weight 6.60 ± 0.00 g). After feeding trail, fish were challenged by Vibrio harveyi for 7 days. The results showed that each treatment had better survival rate between 96.67% and 100%. Fish fed with control and T6 diet showed lower final weight and weight gain rate as compared to other diets. The feed conversion ratio of fish fed on T12 and T18 diet had no significant difference compared to control diet. As compared to control diet, other diets had no significant differences on specific growth rate and temperature growth coefficient. Fish fed with T6 diet had highest liver glutathione reductase activities. No significant differences were observed in liver superoxide dismutase activities in fish fed with T6, T12, T25, T31 and control diet. Fish fed on T18 diet had lowest hepatic malondialdehyde contents and a highest relative per cent survival. According to a broken‐line model, the recommended substituted ratio of TM for FM was estimated to be 12.3% for grouper obtaining maximum WGR, corresponding to additive amount of TM is 4.92%. [ABSTRACT FROM AUTHOR]

The effects of a dietary protease-complex on growth performance, body composition, digestive and immune enzyme activity of Litopenaeus vannamei and its resistance to a pathogenic Vibrio parahaemolyticus were assessed in a 9-week trial. A high fish meal diet ( HF) containing 200 g kg−1 fish meal and a low fish meal diet ( LF) containing 100 g kg−1 fish meal were designed as a positive and negative control respectively. Three other diets ( LF+125P, LF+150P, and LF+175P) were manufactured by supplementing graded level of a protease-complex (125, 150 and 175 mg kg−1, respectively) to the LF diet. All diets were formulated to be iso-proteic and iso-energetic. Most performance indices of shrimp fed the LF+175P diets were similar to the HF diet. Among the digestive enzymes, trypsin, lipase and amylase activity in hepatopancreas of shrimp fed LF+175P diets (4576 U mg−1 protein and 16, 32 U g−1 protein, respectively) were higher than those fed the LF diets but lower than the HF diets ( P < 0.05). Total superoxide dismutase and polyphenol oxidase contents in both serum and hepatopancreas were higher and serum malondialdehyde content and the cumulative mortality during disease challenge tests were lower for the diets containing the protease-complex than those fed the LF diets ( P < 0.05) with no difference with those fed the HF diets. [ABSTRACT FROM AUTHOR]

The aim of this study was to examine the effects of the immunostimulant combination ( IC) containing β-glucan, A3α-peptidoglycan, vitamin C and vitamin E on the growth performance, non-specific immunity and protection against Vibrio harveyi infection in cobia ( Rachycentron canadum). Fish were fed diets containing six graded levels of IC (0, 1, 2, 3, 4 and 5 g kg−1 diet) for 8 weeks. The results showed that the survival rate ranged from 81.1 to 84.4% with no significant difference among all the groups ( P > 0.05) after the feeding experiment. Dietary IC significantly increased the specific growth rate ( SGR), serum lysozyme, alternative complement pathway ( ACH50) activity, phagocytosis percentage ( PP) and respiratory burst activity of head kidney macrophages of cobia. Moreover, feeding of supplemented diets containing 3.0 g kg−1 IC resulted in significantly lower mortality against the pathogens, V. harveyi compared with the control group. To elevate the growth and immune resistance ability of cobia, the optimal dose of dietary IC administration, determined by second-order polynomial regression analysis was 3.43 and 2.71 g kg−1 diet, respectively, on the basis of the SGR and mortality after challenge with V. harveyi. [ABSTRACT FROM AUTHOR]

Abstract: The present study was performed to investigate the effects of various levels of dietary Bacillus subtilis and chitosan on the growth performance, non-specific immunity and protection against Vibrio harveyi infection in cobia, Rachycentron canadum. Fish were fed with the control diet and six different experimental diets containing three graded levels of B. subtilis at 2 × 1010 CFU g−1 (0.0, 1.0, 2.0 g kg−1 diet) for each of two levels of chitosan (3.0 and 6.0 g kg−1 diet). The results of 8 weeks feeding trial showed that the survival rate ranged from 81.3% to 84.0% with no significant difference (P > 0.05). The SGR (%) in the fish fed with dietary treatments was significantly higher than that of the control fish except diet 6 group with 2.0 g kg−1 B. subtilis and 3.0 g kg−1 chitosan. The serum lysozyme activities were significantly higher in 6.0 g kg−1 chitosan groups and no significant differences were observed among B. subtilis levels. The serum ACP activities were significantly higher in 3.0 g kg−1 chitosan groups at 0.0 and 1.0 g kg−1 B. subtilis levels; at low chitosan level, the cobia fed diets with 1.0 g kg−1 B. subtilis had significantly higher serum ACP activity, but at high chitosan level, the cobia fed diets with 2.0 g kg−1 B. subtilis had significantly higher serum ACP activity. The phagocytosis and respiratory burst activity in the fish fed with dietary treatments was significantly higher than that of the control fish except diet 3 group with 6.0 g kg−1 chitosan. Moreover, fish fed the diet containing 2.0 g kg−1 B. subtilis and 6.0 g kg−1 chitosan had significantly higher post-challenge survival on the 7th day following V. harveyi infection and post-challenge survival showed clearly the synergistic effect of chitosan and B. subtilis. Based on these results, the combination of 1.0 g kg−1 B. subtilis and 6.0 g kg−1 chitosan is optimal for the growth, innate immunity and disease resistance of cobia with an 8-week oral administration. [Copyright &y& Elsevier]

A total of 6000 shrimp (initial body weight of 0.82 ± 0.02 g) were randomly distributed into twelve concrete pools (4.5 m × 3.5 m × 0.5 m) with 500 shrimp per pool and 3 pools per diet, respectively. Four kinds of isonitrogen and isoenergetic diets were formulated with 0, 0.1%, 0.2% and 0.3% Yucca schidigera extract (YSE), respectively. The experiment lasted 100 d. The results showed as follows: when supplemented with 0.2% dietary YSE, the shrimp weight gain rate significantly increased ( p < 0.05), but no significant change was found in feed conversion ratio, specific growth rate, and survival rate ( p > 0.05). Addition of 0.2% dietary YSE significantly increased the shrimp serum protein content, as well as the activities of acid phosphatase, alkaline phosphatase, nitric oxide synthase, glutamic–pyruvic transaminase, phenol oxidase, and hepatopancreas proteases ( p < 0.05), but did not significantly affect the activities of total superoxide dismutases (T-SOD) and aspartate transaminase ( p > 0.05). In the late culture period (5 th week to 14 th week) the total amount of ammonia-nitrogen, nitrite-nitrogen, nitrate-nitrogen, and reactive phosphorus in the culture water significantly decreased ( p < 0.05). These results indicated that addition of 0.2% YSE in the diet was beneficial to the growth and nonspecific immunity of white shrimp and water quality. [ABSTRACT FROM AUTHOR]

The current study was conducted to evaluate the effects of different levels of yeast culture (YC) supplementation at 0% (YC 0%), 1% (YC 1%), and 2% (YC 2%) on growth, feed conversion ratio, body composition, intestinal morphology, microflora, immune response, and resistance to Vibrio harveyi infection in Litopenaeus vannamei. After 8-weeks feeding trial, the results showed significant improvement (p <.05) in the final weight, weight gain rate, specific growth rate, survival rate and low feed conversion ratio in YC groups than the control. Serum total protein, superoxide dismutase, catalase, alkaline phosphatase, acid phosphatase, lysozyme, and phenol oxidase in shrimps fed diet YC (2%) were significantly higher (p <.05), whereas significantly decreased trend in serum cholesterol, triglyceride, aspartate aminotransferase, and alanine aminotransferase (p <.05) were observed in YC (2%) diet. Proteobacteria, Bacteroidetes , Actinobacteria , and Firmicutes were the core phylum bacteria found in the shrimp intestines. At the genus level, opportunistic pathogenic bacteria, Vibrio was significantly decreased (p <.05) while beneficial bacteria Pseudoalteromonas was increased in YC (2%) group. Intestinal villus height and width in shrimps fed YC diets were significantly improved than the control diet (p <.05). YC groups challenged test significantly showed (p <.05) improved shrimps immune response against V. harveyi infections with YC (2%) recording the highest percentage survival rate (70%). The present study demonstrated that supplementing YC (2%) can improve growth, intestinal microbiota, intestinal morphology, and immune response against V. harveyi infections in L. vannamei. • Dietary yeast culture supplementation enhanced growth performance and immune response of shrimps. • Dietary 2% yeast culture supplementation positively influenced intestinal microflora of shrimps. • Supplementation of yeast culture could protect shrimp against Vibrio harveyi infection. [ABSTRACT FROM AUTHOR]

Abstract The present study assessed the effects of probiotic bacterium Bacillus coagulans ATCC 7050 (BC) fed at different inclusion levels (0 (BO), 1 × 106 (BC1), 1 × 107 (BC2) and 1 × 108 (BC3) CFU g−1 feed) on growth, feed utilization, body composition, intestinal morphology, microflora, immune response, and resistance to Vibrio parahaemolyticus infection in Litopenaeus vannamei. After 56 days of the feeding trial, the survival rate ranged from 83.33 to 94.17% with no significant difference between dietary treatments (P > 0.05). Dietary probiotic supplementation also affected the intestinal microflora composition. At the phylum level, Proteobacteria accounted for the majority of bacteria followed by Bacteroidetes irrespective of the group. At the genus level, the abundance of opportunistic pathogenic bacteria, such as Vibrio , Tenacibaculum , and Photobacterium significantly decreased (P < 0.05) with an increasing probiotic concentration, and BC3 group experiencing the least. Additionally, increasing probiotic inclusion in diet downregulated the abundance of Muricauda , Kangiella, and Shewanella in shrimps, with the least, observed in the BC3 group. However, beneficial bacteria Pseudoalteromonas significantly increased (P < 0.05) in the intestines of shrimp fed BC3 diet (P < 0.05) compared to other groups including the control. Compared to the control, a significant increase (P < 0.05) of the probiotic treated groups in the final weight, weight gain rate (WGR), specific growth rate (SGR), condition factor (K), activity of lysozyme (LYZ), acid phosphatase (ACP), superoxide dismutase (SOD), total protein (TP), albumin (ALB) in serum, glutathione peroxidase (GSH-Px) in serum and liver, and a significant decrease (P < 0.05) in feed conversion ratio (FCR), triglyceride (TG) in serum, and Malondialdehyde (MDA) in serum and liver were achieved. Increasing probiotic treatment again improved the digestive ability, thus; a significant increase in the activities of lipase, amylase, trypsin, and an enhancement in the villus height, villus width, and muscle thickness of the intestines of the shrimps which correspondingly alleviated intestinal injury. Furthermore, the supplementation of probiotics in challenge test significantly (P < 0.05) enhanced the resistance of shrimp against V. parahaemolyticus infection recording BC3 to receive the highest relative percentage survival (RPS) value of 76%. In conclusion, higher inclusion levels of probiotic BC at 1 × 108 CFU g−1 feed (BC3) in diets can be considered to enhance the growth, intestinal morphology and microflora, immune response and resistance to Vibrio parahaemolyticus of L. vannamei. Highlights • The growth performance, body composition of shrimps fed with diet containing B. coagulans ATCC 7050 significantly improved. • The intestinal morphology and microflora of L. vannamei was shaped by B. coagulans ATCC 7050 supplementation. • Antioxidant and immune responses were enhanced after B. coagulans ATCC 7050 supplementation. • The survival of L. vannamei against V. parahaemolyticus challenge was enhanced after B. coagulans ATCC 7050 supplementation. • Optimal dietary dose of B. coagulans was 108 CFU/g diet. [ABSTRACT FROM AUTHOR]

• Supplementing yeast culture in low fishmeal diets improves growth performance and immune response of shrimps. • Yeast culture supplementation in diets positively influenced intestinal health of shrimps. • Increase supplementation of yeast culture protects shrimp against Vibrio harveyi infection. The aim of this experiment was to investigate the effects of reducing dietary fishmeal (FM) with yeast culture (SYC) supplementation on growth, immune response, intestinal microbiota, intestinal morphology, and disease resistance of Litopenaeus vannamei. A total of 480 shrimps with an average initial body weight of 0.35 ± 0.002 g were randomly distributed into twelve tanks. Three isonitrogenous (40.00 crude protein) and isolipidic (8.00 crude lipids) diets with yeast culture supplementing fishmeal were formulated. The groups were divided into two (2) namely control group and experimental groups. The formulations of the groups were control (0 %, without yeast culture) and the experiment groups (SYC) [(1 % of yeast culture), and (2 % of yeast culture)]. Each diet was delivered in four replicate per treatment group. The results indicate significant improvement on the growth indices (specific growth rate, weight gain rate, survival rate and lower feed conversion ratio) with yeast culture treatment group after 56 days feeding trials (P < 0.05). Total hemolymph protein, superoxide dismutase, catalase, alkaline phosphatase, acid phosphatase, lysozyme and phenoxidase were enhanced but low aspartate aminotransferase, alanine aminotransferase, and glucose were observed in shrimp fed yeast culture diets (P < 0.05). The SYC groups showed insignificant differences in hemolymph cholesterol and triglyceride. Proteobacteria, Bacteroidetes, and Actinobacteria were the dominant bacteria found in all the SYC groups. At the genus level, Vibrio was significantly decreased (P < 0.05) in 2 % yeast culture diets supplemented group whereas the beneficial bacteria Pseudoalteromonas was significantly enhanced. Moreover, intestinal villus length and width in shrimps fed yeast culture diets were improved (P < 0.05). Dietary yeast culture supplementation can improve growth, intestinal health, immune response, and resistance against Vibrio harveyi infections in L. vannamei. [ABSTRACT FROM AUTHOR]