Mean Initial Wet Weight Research Articles

Comparison of effect of chitosan and chitosan nano emulsion on growth performance, water quality and protein retention of Koi fish (Cyprinus Caprio Koi)

Koi fish is one of high economic value fish because of its beautiful body shape and colour. Its colour is influenced by the protein and carotenoid-rich feed. The sources of protein and carotenoid used as supplement were chitosan and chlorella. The purpose of this study is to evaluate the effect of protein and carotenoid-rich feed using chitosan, chitosan nano emulsion and chlorella on growth performance, water quality and protein retention of Koi Fish. Experiment was conducted by preparing the chitosan nano emulsion and formulated as Koi fish feed. The growth performance and protein retention of Koi fish and water quality were evaluated using ANOVA. In the experiment, Koi fish (mean initial wet weight 1.49 g) were fed with three diets (control, chitosan and Nano chitosan emulsion) in triplicate for 60 days. The result shows that growth performance of Koi fish fed chitosan nano emulsion diet was higher (P<0.05) than other diets. Koi fish in chitosan diet group was higher (P<0.05) than of Koi in control but no statistical difference was found in Koi of chitosan nano emulsion diet groups with protein retention 57.03 ± 1.76 and the water quality showed Ph 7.32, DO = 6.23, NH3 = 0.03, NO2 = 0.0075 and NO3 = 0.03 mg/L.

Dietary values of macroalgae Porphyra haitanensis in Litopenaeus vannamei under normal rearing and WSSV challenge conditions: Effect on growth, immune response and intestinal microbiota

Two trials were conducted to determine the effects of dietary macroalgae Porphyra haitanensis on growth, immunity and intestinal microbiota of Litopenaeus vannamei. In trial 1, shrimp (mean initial wet weight about 0.64 g) were fed with seven diets (P0, P1, P2, P3, P4, P5 and P6) containing 0% (basal diet), 1%, 2%, 3%, 4%, 5% and 6% P. haitanensis in triplicate for 60 days. Growth performance (weight gain, WG; specific growth rate, SGR) of shrimp fed the P4 diet were significantly higher than that of shrimp fed P0, P5 and P6 diets (P < 0.05) but without significant differences with shrimp fed P1-P3 diets (P > 0.05). Hepatopancreas phenoloxidase (PO) activity of shrimp fed the P. haitanensis containing diets was significantly higher than that of shrimp fed the basal diet (P0) (P < 0.05). Total haemocyte count (THC) of shrimp fed basal diet (P0) was significantly lower than that of shrimp fed diets containing P. haitanensis. Our results declared that dietary P. haitanensis supplementation increases the abundance of beneficial bacterials such as Nitrosopumilus, Marinobacter or Bifidobacterium and reduces the abundance of harmful bacterias such as Vibrio, and especially pronounced in P4 diet treatment. In trial 2, a WSSV injection challenge test was conducted for 7-day after the rearing trial and shrimp survival was also compared among treatments. A sudden shrimp death was found from the 4th day, and values of survival of shrimp fed the P3-P4 diets were higher than that of shrimp fed other diets during 4–7 days challenge test. The immune response in trial 2 were characterized by higher superoxide dismutase activity (SOD) and PO activities, lower THC and higher HCT compared to levels found in trial 1. In conclusion, suitable dietary P. haitanensis could enhance the growth performance, antioxidant capacity and alter total bacterial numbers or microbial diversity of L. vannamei and furthermore reduce oxidative stress and immune depression challenged by WSSV injection stress, and the level of P. haitanensis supplemented in the diet should be between 2.51% and 3.14%.

Dietary values of Forsythia suspensa extract in Penaeus monodon under normal rearing and Vibrio parahaemolyticus 3HP (VP3HP) challenge conditions: Effect on growth, intestinal barrier function, immune response and immune related gene expression

Two trials were conducted to determine the effects of dietary Forsythia suspensa extract (FSE) on shrimp, Penaeus monodon, first on growth performance, second on the immune response and immune related gene expression of shrimp. In trial 1, shrimp (mean initial wet weight about 3.02 g) were fed with five diets containing 0% (basal diet), 0.01%, 0.02%, 0.04% and 0.06% FSE in triplicate for 60 days. Growth performance (final body wet weight, FBW; weight gain, WG; biomass gain, BG) of shrimp fed FSE diets were higher (P < 0.05) than that of shrimp fed the basal diet. The survival among all the diets treatments were above 90% and no significant difference was revealed among them (P > 0.05). The antioxidant capacity (total antioxidant status, TAS; glutathione peroxidase, GSH-Px) appears in the trend of firstly increasing then decreasing with the increasing of dietary FSE levels. The highest value of TAS and GSH-Px were found in shrimp fed 0.02% FSE diet and were significantly higher than that of shrimp fed the basal and 0.06% FSE diets (P < 0.05). Hepatopancreas malondialdehyde (MDA) of shrimp fed FSE 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 FSE diets. Haemolymph clotting time of shrimp had the opposite trend with the total haemocyte count of shrimp. No significant differences were found in haemolymph biomarkers of intestinal permeability (endotoxin and diamine oxidase) and in molecular gene expression profiles of heat shock protein 70 (Hsp 70) mRNA and hypoxia inducible factor-1α (HIF-1α) mRNA in haemolymph of shrimp among all diet treatments (P > 0.05). In trial 2, a pathogenic strain of Vibrio parahaemolyticus 3HP (VP3HP) injection challenge test was conducted for 6-day after the rearing trial and shrimp survival were also compared among treatments. Survival of shrimp fed diets supplemented with 0.01%–0.02% FSE were higher than that of shrimp fed the basal and 0.06% FSE diets (P < 0.05). Dietary FSE supplementation produced stronger hepatopancreas antioxidant capacity (TAS, GSH-Px) (P < 0.05) and higher glutathione (GSH) level (P < 0.05), lower superoxide dismutase activity (SOD) (P < 0.05), higher total haemocyte count (P < 0.05), lower haemolymph clotting time (P < 0.05), lower MDA and carbonyl protein concentration (P < 0.05), lower haemolymph biomarkers of intestinal permeability (endotoxin and diamine oxidase) (P < 0.05), generated lower molecular gene expression profiles of HSP 70 mRNA and higher HIF-1α mRNA (P < 0.05) than the basal diet. The immune response were characterized by lower TAS and higher antioxidant enzyme activities (SOD, GSH-Px) and higher oxidative stress level (MDA and carbonyl protein) and higher haemolymph biomarkers of intestinal permeability (endotoxin and diamine oxidase) compared to levels found in trail 1. However, the total haemocyte counts and haemolymph clotting times were not changed in 0.01%–0.02% FSE diets treatments between trial 1 and trial 2 (P > 0.05). The molecular gene expression profile of Hsp 70 mRNA was increased while HIF-1α mRNA was decreased when compared to trial 1. In conclusion, results suggested that dietary intake containing FSE could enhance the growth performance and antioxidant capacity of P. monodon and furthermore reduce oxidative stress and immune depression challenged by a pathogenic strain of Vibrio parahaemolyticus stress. Considering the effect of FSE on both growth performance and immune response of P. monodon, the level of FSE supplemented in the diet should be between 0.01% and 0.02%.

Effect ofl-ascorbyl-2-polyphosphate supplementation on growth performance, body composition, antioxidative capacity and salinity stress tolerance of juvenile Pacific white shrimp,Litopenaeus vannamei

An 8-week feeding trial was conducted to evaluate the effects of ascorbic acid (AsA), in the form of l-ascorbyl-2-polyphosphate (LAPP) on growth performance, body composition, antioxidative capacity and salinity stress tolerance of juvenile Pacific white shrimp, Litopenaeus vannamei. Five practical diets (46% crude protein and 7.6% lipid) supplemented with graded levels of AsA (14.64, 48.55, 84.98, 308.36 and 639.27 mg kg−1 diet) were fed to five replicate groups of L. vannamei (mean initial wet weight 0.57 g). No significant differences were found on growth performance among all treatments. However, whole body lipid content significantly decreased with dietary AsA levels increasing. Activities of total antioxidant capacity, glutathione reductase and glutathione peroxidase were significantly affected by dietary AsA levels. Shrimp fed LAPP-free diet had higher malondialdehyde content than those fed the diets supplemented with LAPP. Dietary AsA levels higher than 308.36 mg kg−1 diet increased the survival of shrimps after 1, 2 and 3 h of acute salinity change. Broken-line regression analysis on survival after 3 h of salinity stress and second-degree polynomial regression analysis on glutathione reductase data indicated that the optimal dietary AsA requirement of L. vannamei was estimated to be 306.39, 319.75 mg kg−1 diet respectively.

육상어류양식장 고형오물을 공급한 해삼(Apostichopus japonicus)의 성장과 에너지 수지

We conducted a 90-day feeding experiment to evaluate the growth and energy budget of the sea cucumber Apostichopus japonicus. Sea cucumbers with a mean initial wet body weight of 3.03±0.06 g were fed one of the following three diets: an eel fecal solid diet, rainbow trout fecal solid diet, or a commercial diet at a water temperature of 17±1°C and salinity of 32±1 psu. The results suggested that the diets affected the final body weight, specific growth rate (SGR), food ingestion, feces production ratio, and hence the growth and energy budget of the sea cucumbers. Sea cucumbers fed the eel and rainbow trout fecal solid diets showed poorer energy absorption, assimilation, and growth than those fed the commercial diet. The sea cucumbers fed the commercial diet had a significantly higher SGR and proportion of energy used for growth than those fed the other two diets. Sea cucumbers fed the rainbow trout fecal solid diet showed a comparatively higher ingestion rate and feces production ratio than those fed the commercial diet. The eel and rainbow trout fecal solid diets, therefore, were not suitable for sea cucumbers in intensive cultivation. Our findings will facilitate further development of more appropriate diets for culture of sea cucumber.

Storage characteristics, nutritive value, and fermentation characteristics of alfalfa packaged in large-round bales and wrapped in stretch film after extended time delays

The production of baled silage is attractive to producers because it offers advantages over dry hay, particularly by limiting risks associated with wet or unstable weather conditions. Our objectives were to test the effects of delayed wrapping on silage fermentation, storage characteristics, and the nutritive value of baled alfalfa silages. To accomplish this, large-round bales of alfalfa were wrapped in plastic film within 4h of baling (d 0), or after delays of 1, 2, or 3 d. A secondary objective was to evaluate a prototype bale wrap containing an O2-limiting barrier (OB) against an identical polyethylene wrap without the O2 barrier (SUN). Sixty-four 1.19×1.25-m bales of alfalfa were made from 4 field blocks at a mean moisture concentration of 59.1±4.3% with a mean initial wet bale weight of 473±26.4kg. Two bales per field block were assigned to each combination of bale wrap (SUN or OB) and wrapping time (0, 1, 2, or 3 d postbaling), and one bale of each pair was fitted with a thermocouple placed in the geometric center of each bale. All bales were sampled after a 97-d storage period. Internal bale temperatures, recorded at the time bales were wrapped, were greater for all bales with wrapping delays compared with bales wrapped on d 0 (54.9 vs. 34.9°C), and increased to a maximum of 63.9°C after a 3-d delay exhibiting a linear effect of time delay. Total silage fermentation acids (lactic, acetic, propionic, butyric, and isobutyric) were greatest when bales were wrapped on d 0 compared with all bales wrapped with time delays (4.64 vs. 2.26% of DM), and declined with linear and quadratic effects of wrapping delay. Total fermentation acids also were related quadratically to internal bale temperature by regression [y (% of DM)=0.0042x2 – 0.50x + 17.1; R2=0.725]. Similar responses were observed for lactic acid, except that trends were linear, both for orthogonal contrasts evaluating length of wrapping delay, and in regressions on internal bale temperature [y (% of DM)=−0.046x + 3.5; R2=0.663]. Butyric acid also was detected, regardless of treatment, but was greatest within bales wrapped on d 0 compared with those with wrapping delays (0.99 vs. 0.38% of DM), and a similar response (0.68 vs. 0.52% of DM) was observed for NH3-N, suggesting that clostridial activity occurred during silage fermentation. Based on these results, silage fermentation characteristics and the nutritive value declined with time delays before wrapping, but responses were exacerbated when delays exceeded 1 d.

Comparison effect of dietary astaxanthin and β-carotene in the presence and absence of cholesterol supplementation on growth performance, antioxidant capacity and gene expression of Penaeus monodon under normoxia and hypoxia condition

Abstract Two trials were conducted to determine the effects of two different carotenoid sources on shrimp, Penaeus monodon , first on growth performance, secondly on the immune response of shrimp was investigated with an air emersion challenge. In trial 1, P. monodon (mean initial wet weight about 2.07 g) were fed five diets in triplicate; a basal diet (D1) without carotenoids; two diets formulated to supply 0.1% astaxanthin alone (D2), combination of 0.1% astaxanthin and 1% cholesterol (D3); two diets with 0.25% β-carotene alone (D4), combination of 0.25% β-carotene and 1% cholesterol (D5). Growth performance (final body weight, FBW; weight gain, WG; biomass gain, BG) and survival of shrimp fed D3 showed the highest values. The apparent digestibility coefficients (ADCs) of carotenoids in carotenoid-supplemented diets (D2–D5) were quietly high (> 90%), and cholesterol supplementation did not significantly improve the carotenoid ADCs any more. However, cholesterol addition significantly enhanced the tissue carotenoid retention efficiencies in astaxanthin-supplemented diet treatments (D3 vs D2) but not in β-carotene-supplemented diet treatments (D5 vs D4). Hepatopancreas malondialdehyde (MDA) and hemolymph clotting time of shrimp fed carotenoid-supplemented diets (D2–D5) were lower ( P P P > 0.05) were found in expression profiles of heat shock protein 70 (Hsp 70) mRNA and hypoxia inducible factor-1α (HIF-1α) mRNA in hepatopancreas of shrimp among all diet treatments. In trial 2, the shrimp were exposed to air during a simulated live transportation for 36 h after the rearing trial 1. No mortalities were observed in all diet treatments after 36 h of simulated live transportation. Total hemocyte counts of shrimp fed the basal and β-carotene-supplemented diets (D1, D4 and D5) significantly declined ( P P P P P. monodon , and the supplement of cholesterol could positively enhance the efficiency of astaxanthin but not β-carotene.

Suitable dietary chitosan improves the growth performance, survival and immune function of tiger shrimp,Penaeus monodon

Different levels of dietary chitosan on growth performance, survival and stress tolerance to air exposure was studied in tiger shrimp, Penaeus monodon. Shrimp (mean initial wet weight about 1.16 g) were fed with six different diets (C0, C0.05, C0.1, C0.2, C0.3 and C0.4) containing six level of chitosan (0%, 0.05%, 0.1%, 0.2%, 0.3% and 0.4% respectively) in triplicate for 60 days. Growth performance [final body wet weight (FBW); weight gain (WG); biomass gain (BG)] of shrimp fed chitosan-containing diets were higher (P 0.05) in shrimp fed C0.3 diet group. Whole body and muscle lipid contents decreased with increasing dietary chitosan levels. Plasma total cholesterol and triglyceride contents of shrimp fed C0 diet was significantly higher (P < 0.05) than that of shrimp fed chitosan-containing diets. Plasma alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities of shrimp fed C0 diet were higher than those of shrimp fed chitosan-containing diets. Digestive gland malondialdehyde (MDA) and carbonyl protein contents of shrimp fed chitosan-containing diets were lower (P < 0.05) than that of shrimp fed C0 diet. Total haemocyte count of shrimp fed C0 diet was lower (P < 0.05) than that of shrimp fed chitosan-containing diets. On the contrary, the haemolymph clotting time of shrimp fed C0 diet was higher (P < 0.05) than that of shrimp fed chitosan-containing diets. In conclusion, all results suggested that dietary intake containing 0.1% and 0.2% chitosan enhanced the growth of shrimp, whereas a higher level than 0.3% and 0.4% decreased growth of shrimp. Second-degree polynomial regression analysis of WG and BG indicated that the optimum supplement of dietary chitosan level should be 0.19–0.21%.

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.

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%.

Comparison of effect of chitin, chitosan, chitosan oligosaccharide and N-acetyl-d-glucosamine on growth performance, antioxidant defenses and oxidative stress status of Penaeus monodon

Two trials were conducted to evaluate the effects of chitin and its derivatives (chitosan, chitosan oligosaccharides and N-acetyl-d-glucosamine) on shrimp, Penaeus monodon, first on growth performance, secondly on antioxidant defenses and oxidative stress status of digestive gland. In the first experiment (trial 1), Shrimp (mean initial wet weight 1.49g) were fed with five diets (control diet; chitin diet; chitosan diet; chitosan oligosaccharides diet and N-acetyl-d-glucosamine diet) in triplicate for 70days. Growth performance (final body wet weight, FBW; weight gain, WG; biomass gain, BG) of shrimp fed chitosan diet was higher (P<0.05) than that of shrimp fed the other diets. Survival of shrimp in chitosan diet groups was higher (P<0.05) than that of shrimp in control, chitosan oligosaccharides and N-acetyl-d-glucosamine diet groups, but no statistical difference was found in survival of shrimp in chitin and chitosan diet groups. The total antioxidant status (TAS) and glutathione peroxidase (GSH-Px) activity of shrimp fed chitin, chitosan and chitosan oligosaccharides diets were higher (P<0.05) than those of shrimp fed control and N-acetyl-d-glucosamine diets. The superoxide dismutase (SOD) activity of shrimp fed control diet was higher (P<0.05) than that of shrimp fed other diets. Digestive gland malondialdehyde (MDA) and carbonyl protein contents of shrimp fed chitin and chitosan diets were lower that those of shrimp fed other diets (P<0.05). A low dissolved oxygen (DO) stress test was conducted for 7-day after the rearing trial (trial 2). The antioxidant response was characterized by higher TAS and higher antioxidant enzyme activities (SOD, PO, GSH-Px) and higher oxidative stress levels (MDA and carbonyl protein contents) in the digestive gland compared to levels found in trial 1. Survival of shrimp fed chitin and chitosan diets was higher (P<0.05) than that of shrimp fed other diets after trial 2. The glutathione (GSH) content, TAS, PO and GSH-Px activities of shrimp fed chitosan diet were higher (P<0.05) than those of shrimp fed other diets. The SOD activity of shrimp fed chitosan diet was lower (P<0.05) than that of shrimp fed control, chitosan oligosaccharides and N-acetyl-d-glucosamine diets, but no difference (P>0.05) was found between shrimp fed chitin and chitosan diets. Moreover, the oxidative stress levels (MDA and carbonyl protein contents) recorded in the digestive gland with shrimp submitted to the chitin and chitosan diets were lower. In conclusion, results suggested that dietary intake containing chitin or chitosan could enhance the growth performance of P. monodon and improve its resistance to DO stress.

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.

Effect of seven carbohydrate sources on juvenile Penaeus monodon growth performance, nutrient utilization efficiency and hepatopancreas enzyme activities of 6-phosphogluconate dehydrogenase, hexokinase and amylase

Seven isoproteic (370g/kg) and isolipidic (90g/kg) diets containing seven various carbohydrate sources (wheat starch, sucrose, potato starch, maize starch, dextrin, maltose and glucose) at the same quantities (200g/kg) were fed to triplicate groups of Penaeus monodon (1.92±0.01g mean initial wet weight) for 74 days. All shrimp fed glucose and maltose-containing diets died within the first two weeks. After a 74-day feeding trial, the highest (P<0.05) weight gain (WG, %) and biomass gain (BG, g) were obtained with shrimp fed wheat starch or sucrose-containing diet; whereas, the lowest (P<0.05) WG and BG were observed for shrimp fed a dextrin-containing diet. The survival of shrimp fed wheat starch, sucrose, potato starch and maize starch-containing diets was higher (P<0.05) than shrimp fed a dextrin-containing diet, but no difference (P>0.05) was found among shrimp fed wheat starch, sucrose, potato starch and maize starch-containing diets. The highest and lowest protein contents of whole body and muscle were obtained from shrimp fed wheat starch and dextrin-containing diets, respectively. Diets containing dextrin or maize starch had inferior values of apparent digestibility coefficients (ADCs) of protein, dry matter and energy (P<0.05) compared to the three other diets, while dextrin or potato starch-containing diet gave the worst response in terms of ADC of carbohydrate (P<0.05). The highest 6-phosphogluconate dehydrogenase (6PGDH) and hexokinase (HK) activities were observed in shrimp fed a wheat starch-containing diet. Hepatopancreas amylase activity of shrimp fed a wheat starch and sucrose-containing diet was higher (P<0.05) than that of shrimp fed other diets. In conclusion, shrimp fed the wheat starch or sucrose-containing diet had the best growth performance. The activities of hepatopancreas enzymes involved in carbohydrate uptake (HK) and NADPH generation (6PGDH) increased preferentially as dietary carbohydrates became more suitable to support the shrimp's rapid growth. All these data suggest that wheat starch and sucrose are the more suitable source of dietary carbohydrate and have the same nutritional value in P. monodon feed.

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.

Effects of different dietary wheat starch levels on growth, feed efficiency and digestibility in grass carp (Ctenopharyngodon idella)

An experiment was conducted to determine the effect of dietary wheat starch on grass carp (Ctenopharyngodon idella) in terms of growth performance, feed efficiency and digestibility. Five isoproteic (23.5%) and isolipidic (5.7%) diets with five supplemented levels of wheat starch (D20, D26, D33, D40 and D47 with 20, 26, 33, 40 and 47%, respectively) were fed to triplicate groups of grass carp (mean initial wet weight 6.9 ± 0.1 g) for 8 weeks. Results showed that weight gain (WG, %), feed efficiency (FE, %) and protein efficiency ratio (PER) in D20, D26 and D33 treatments were significantly higher than those in D40 and D47 treatments (P 33%) despite fish ate increasing levels of dietary digestible energy. Furthermore, excess digestible carbohydrate was to some extent converted to lipid that was deposited in various tissues. Most importantly, grass carp could endure high levels of cellulose without any negative effect on growth and digestibilities of dietary protein and carbohydrate.

Effects of dietary chitosan on growth, survival and stress tolerance of postlarval shrimp, Litopenaeus vannamei

The effect of chitosan, a polymer of glucosamine obtained by the deacetylation of chitin, on growth, survival and stress tolerance was studied in postlarval Litopenaeus vannamei. An experiment was performed with postlarval shrimp (mean initial wet weight 1.2 mg) fed five isoenergic and isonitrogenous diets containing five supplemented levels of chitosan (0, 0.5, 1, 2 and 4 g kg−1 diet, respectively). The five compound diets (C0, C0.5, C1, C2 and C4) sustained shrimp growth throughout the experiment. Growth performance (final body weights; weight gain; SGR: specific growth rate) in shrimp fed diet C2 was significantly higher than that in shrimp fed diets C0, C0.5 and C1 (P < 0.05), diet C4 treatment provided intermediate growth result. The survival in shrimp fed diet C1 was significantly higher than that in shrimp fed C0 diet (P < 0.05), other diets treatments gave the intermediate survival results. No significant differences were found in growth and survival between diet C2 and C4 treatments. After 9 days of a stress tolerance test, survival in shrimp fed diets C1, C2 and C4 was significantly higher than that in shrimp fed diets C0 and C0.5. We concluded from this experiment that the incorporation of a moderate dietary chitosan was beneficial to the development of postlarval L. vannamei. Considering the effect of chitosan on both growth and survival of postlarval L. vannamei, second-degree polynomial regression of SGR and survival indicated optimum supplement of dietary chitosan at 2.67 and 2.13 g kg−1, respectively, so the level of chitosan supplemented in the diet should be between 2.13 and 2.67 g kg−1.

Influence of dietary phospholipids level on growth performance, body composition and lipid class of early postlarval Litopenaeus vannamei

One experiment was conducted to determine the nutritive value of phospholipids on growth performance of early postlarval shrimp, Litopenaeus vannamei. Five isoenergic and isonitrogenous diets with five supplemented levels of phospholipids (P1, P2, P3, P4 and P5 with 0, 10, 20, 40 and 80 g kg⁻¹ diet, respectively) were fed to triplicate groups of L. vannamei (mean initial wet weight 0.8 mg) for 27 days. After the 27-day feeding trial, the lowest weight gain (WG, %) and specific growth rate (SGR, % day⁻¹) was found in P1 treatment, the highest WG and SGR was found in P3, P4 and P5 treatments, P2 treatment provided intermediate result and showed significant difference compared to P1, P3, P4 and P5 treatments. Shrimp fed the P1 diet had significantly lower survival than shrimp fed other diets, while no significant difference was found in survival among P2, P3, P4 and P5 treatments. Broken-line analysis on WG indicated that the optimum dietary phospholipids for early postlarval shrimp, L. vannamei, is 45.96 g kg⁻¹ diet.

Effect of Feeding Strategy and Carbohydrate Source on Carbohydrate Utilization by Grass Carp (&lt;i&gt;Ctenopharyngodon idella&lt;/i&gt;)

Problem statement: Feeding strategy is the important factor in aquacul ture. Feeding strategy not only could affect the growth performan ce of grass carp and feed efficiency, but also coul d affect the quality and environment of water resourc e. We have proved that glucose was more suitable than starch as the carbohydrate source for grass ca rp under the restricted feeding frequency. While different feeding strategies may have resulted in t he differences in carbohydrate utilization among fish species. No studies have so far been reported that compare the utilization of carbohydrate source in different feeding strategy of grass carp. Approach: A 9-weeks growth trial was conducted to determine the effect of feeding frequency (2, 6, 12 and 23 meals day -1 ) and two different carbohydrate source (30% starch versus 30% glucose) on the carbohydrate utilization of grass carp (Ctenopharyngodon idella ). Both of the two diets with the same feeding rate s but with four different feeding frequencies were fed to triplicate groups o f grass carp (mean initial wet weight 35.94±1.86 g) . Results: In the glucose diet groups, significantly (p<0.05) higher Final Body Weight (FBW, g), Weight Gain (WG, %), Specific Growth rate (SGR, % day -1 ), Feed Efficiency (FE, %), Protein Efficiency Rati o (PER), body lipid and serum Triglyceride (serum TG) were observed in the 6, 12 and 23 meals day -1 -1 feeding treatments provided intermediate results a nd were not significantly different from the 2 and 6 meals day -1 feeding treatments. When compared the effects between the glucose and starch diet groups in the same feeding frequency, s ignificantly (p<0.05) higher FBW, WG, SGR, FE and PER were observed in the glucose than the starc h fed grass carp, only body lipid content was significantly higher in grass carp fed the starch t han the glucose diets. Conclusion: It suggested that 6 meals day -1 feeding was sufficient for the optimal growth and feed efficiency for grass carp on 35.1- 37.5 g. Furthermore, the growth performance also su ggested that glucose was superior to starch as the carbohydrate source for grass carp under the feedin g frequency of 6, 12 and 23 meals day -1 .

Effect of Dietary Astaxanthin on Growth, Survival, and Stress Tolerance of Postlarval Shrimp, Litopenaeus vannamei

Abstract The effect of dietary astaxanthin on growth, survival, and stress tolerance was determined in postlarval Litopenaeus vannamei. An experiment was performed with postlarval shrimp (mean initial wet weight 1.2 mg) fed four isoenergic and isonitrogenous diets containing four supplemented levels of astaxanthin (0, 100, 200, and 400 mg/kg diet, respectively). Shrimp fed diets containing 100, 200, and 400 mg astaxanthin/kg diet for 30 d showed higher weight gain (WG, %) and survival compared to the control (without supplementation of astaxanthin). Specific growth rate (SGR, %/day) and final body wet weight (FBW, mg) showed the same pattern as WG. There were no significant differences in growth performance (FBW, WG, and SGR) among the groups fed the diets with astaxanthin supplementation at the termination of feeding trial. Survival of shrimp in the control and 100 mg/kg diet treatments was significantly lower than that of shrimp in the treatments with 200 and 400 mg/kg diet. After 9 d of a stress tolerance test, survival of shrimp in the 200 and 400 mg astaxanthin/kg treatments was significantly higher than that of shrimp in the 0 and 100 mg astaxanthin/kg treatments (P &lt; 0.05). We concluded from this experiment that astaxanthin was a necessary ingredient for the development of larval L. vannamei. Considering the effect of astaxanthin on both, growth performance and survival of postlarval L. vannamei, the level of astaxanthin supplemented in the diet should be between 100 mg and 200 mg/kg of diet.

Nutrient values of dietary ascorbic acid (l-ascorbyl-2-polyphosphate) on growth, survival and stress tolerance of larval shrimp,Litopenaeus vannamei

l-ascorbyl-2-polyphosphate (ApP) was used as a vitamin C source to investigate the ascorbic acid (AsA) requirements on growth performance and stress resistance of the larval white shrimp, Litopenaeus vannamei. Five isoenergetic and isonitrogenous fish meal-fish protein hydrolysate-based diets with five levels of ApP, AsA equivalent to 91.8, 188, 271, 360 and 436 mg kg−1 diet were fed to triplicate groups of L. vannamei (mean initial wet weight 1 mg) for 32 days. The diet with AsA 91.8 mg kg−1 showed high cumulative mortality after 10 days of feeding. After the 32-day trial, the shrimp that fed the diet had significantly lower survival and weight gain (WG, %) than those that fed 188, 271, 360 and 436 mg AsA kg−1 diets. Specific growth rate (SGR, % day−1) and final body wet weight (FBW, mg) showed the same pattern as WG (%). There were no significant differences in growth performance (FBW, WG and SGR) among the groups that fed 188, 271, 360 and 436 mg kg−1 of AsA at the termination of feeding trial. Broken-line regression analysis on WG indicated that 191 mg AsA kg−1 in the diet was the optimum for larval L. vannamei. On the contrary, dietary level of more than 360 mg AsA kg−1 was needed to ensure high resistance to stressful conditions such as low dissolved oxygen stressors.