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1.
Bacillus circulans PB7, isolated from the intestine of Catla catla, was evaluated for use as a probiotic supplement in the feeds for the fingerlings of Catla catla. The effect of supplement on the growth performance, feed utilization efficiency, and immune response was evaluated. Catla fingerlings (ave. wt. 6.48 ± 0.43 g) were fed diets supplemented with 2 × 104 (feed C1), 2 × 105 (feed C2), and 2 × 106 (feed C3) B. circulans PB 7 cells per 100 g feed for 60 days at 5% of the body weight per day in two equal instalments in triplicate treatments. The control feed (CC) was not supplemented with the B. circulans. All the feeds were isocaloric and isonitrogenous. Fish fed with feed C2 displayed better growth, significantly (P ≤ 0.05) highest RNA/DNA ratio, a lower feed conversion ratio (FCR), and a higher protein efficiency ratio (PER) than the other experimental diets. Highest carcass protein and lipid was also observed in the fish fed C2 feed compared to the others. Significantly (P ≤ 0.05), highest protease was recorded in fish fed feed C2 (47.9 ± 0.016) and lowest in fish fed feed C3 (32.10 ± 0.009), where α-amylase activity did not differ significantly (P ≤ 0.05) beyond the lowest inclusion level. ALP, ACP, GOT, and GPT in the liver of Catla catla were the highest (P ≤ 0.05) in fish fed C2 feed. The highest TSP, albumin, and globulin was observed in fish treated with C2 feed after 60 days feeding trial, but the lowest glucose level was observed in the same treatment. After the feeding trial, the non-specific immunity levels and disease resistance of fish were also studied. Phagocytic ratio, phagocytic index, and leucocrit value were the highest in fish fed feed C2. After the feeding trial, the fish were challenged for 10 days by bath exposure to Aeromonas hydrophila (AH1) (105c.f.u. ml−1 for 1 h, and, after 7 days, 107c.f.u. ml−1 for 1 h). Highest survival percentage was observed in fish fed with feed C2 compared with only 6.66% in the controls, which indicated the effectiveness of B. circulans PB 7 in reducing disease caused by A. hydrophila.  相似文献   

2.
This study was conducted to evaluate the effects of dietary thiamin on the physiological status of the juvenile grouper, Epinephelus coioides. Graded levels of thiamin (0.08, 0.50, 2.12, 3.15, 4.63, 12.37 mg thiamin kg−1 diet) were fed to grouper juveniles (mean weight: 16.97 ± 0.14 g) for 10 weeks. Although fish fed the thiamin-deficient (TD) diet showed no obvious symptoms of thiamin deficiency or increased mortality, those fed the lowest doses of thiamin (0.08 and 0.50 mg thiamin kg−1 diet) had significantly decreased transketolase activity in the liver. In addition, the level of liver thiobarbituric acid reactive substances in fish fed the TD diet was 33–67% higher than that in fish with the thiamin-supplemented diet. There were no significant differences in superoxide dismutase activity between the different groups of fish.  相似文献   

3.
One of the major problems in the shrimp culture industry is the difficulty in producing high-quality shrimp larvae. In larviculture, quality feeds containing a high content of highly unsaturated fatty acids (HUFA) and ingredients that stimulate stress and disease resistance are essential to produce healthy shrimp larvae. In the present study, Penaeus monodon postlarvae (PL15) were fed for 25 days on an unenriched Artemia diet (control; A) or on a diet of Artemia enriched with either HUFA-rich liver oil of the trash fish Odonus niger (B), probionts [Lactobacillus acidophilus (C1) or yeast-Saccharomyces cerevisiae (C2)] or biomedicinal herbal products (D) that have anti-stress, growth-promoting and anti-microbial characteristics. P. monodon postlarvae fed unenriched Artemia exhibited the lowest weight gain (227.9 ± 8.30 mg) and specific growth rate (9.95 ± 0.05%), while those fed the HUFA-enriched Artemia (B) exhibited the highest weight gain and specific growth rate (362.34 ± 12.56 mg and 11.77 ± 0.08%, respectively). At the end of the 25-day rearing experiment, the shrimp postlarvae (PL40) were subjected to a salinity stress study. At both low and high (0 and 50‰) salinities, the group fed the control diet (A) experienced the highest cumulative mortality indices (CMI) 935.7 ± 2.1 and 1270.7 ± 3.1, respectively. Those fed diet D showed the lowest stress-induced mortality, and CMI were reduced by 31.1 and 32.3% under conditions of low and high salinity stress, respectively. A 10-day disease challenge test was conducted with the P. monodon postlarvae (PL40–PL50) by inoculating the shrimp with the pathogen Vibrio harveyi at the rate of 105–107 CFU/ml in all rearing tanks. P. monodon postlarvae fed probiont-encapsulated Artemia diets (C1 and C2) exhibited the highest survival (94.3 and 82.3%, respectively) and lowest pathogen load (V. harveyi) in hepatopancreas (5.2 × 102 ± 9.0 × 10 and 4.6 × 102 ± 9.0 × 10 CFU g−1, respectively) and muscle (2.0 × 102 ± 6 × 10 and 1.7 × 102 ± 8.6 × 10 CFU g−1, respectively) tissues. The shrimp that were fed the unenriched Artemia (Control; A) showed the lowest survival (26.33%) and highest bacterial load in the hepatopancreas (1.0 × 105 ± 5 × 103 CFU g−1) and muscle (3.6 × 104 ± 6 × 102 CFU g−1). The shrimp fed the herbal product (D)-enriched Artemia also exhibited enhanced survival and reduced V. harveyi load in the tissues tested compared to the control diet (A) group. The results are discussed in terms of developing a quality larval feed to produce healthy shrimp larvae.  相似文献   

4.
New cultured ornamental fish namely Lake Kurumoi rainbowfish Melanotaenia parva (Allen) run into reduced of colour performances when reared in the aquaria, consequently, fish feed must be added with carotenoids as a pigment source. The aim of this study was to evaluate the digestibility, growth and pigmentation of astaxanthin, canthaxanthin and lutein in diet. Apparent digestibility coefficients (ADC) of dry matter, lipid, protein, carotenoids, growth and pigmentation were studied in twenty fish after 14 and 56 days of observation. The single‐dose supplementation of 100 mg/kg of astaxanthin, canthaxanthin, or lutein diets on fish was fed by apparent satiation. The basal diet without carotenoids was used as control. The result showed that the ADC of carotenoids of test diets was higher compared to control. Fish fed astaxanthin diet had higher survival rate (96.67 ± 2.89%), colour measurements of lightness (57.60 ± 7.46%), a*‐values (4.66 ± 1.20), total carotenoids content in skin (33.75 ± 5.02 mg/kg) and muscle (2.16 ± 0.74 mg/kg). Astaxanthin also increased the growth after 14 days (2.00% ± 0.19%/days) but there was no significantly different at the end of experiment. The yellowish‐orange colour performance was more rapidly achieved by fish fed astaxanthin diet after 28 days experimentation. These values suggested that dietary carotenoids were required and astaxanthin diet was superior to other diets for skin pigmentation of Lake Kurumoi rainbowfish.  相似文献   

5.
The effect of stocking density on the survival and growth of pikeperch, Sander lucioperca (L.), larvae was examined in two consecutive experiments. In experiment I, 4-day-old larvae [body wet weight (BW): 0.5 mg; total body length (TL): 5.6 mm] were reared in 200-l cylindro-conical tanks in a closed, recirculating system (20 ± 0.5°C) at three stocking densities (25, 50 and 100 larvae l−1) and fed a mixed feed (Artemia nauplii and Lansy A2 artificial feed) for 14 consecutive days. At densities of 25 and 100 larvae l−1, growth rate and survival ranged from 2.7 to 1.9 mg day−1 and from 79.2 to 72.3%, and fish biomass gain ranged from 0.6 to 2.0 g l−1, respectively. There were two periods of increased larval mortality: the first was at beginning of exogenous feeding and the second during swim bladder inflation. In experiment II, 18-day-old larvae (BW: 35 mg; TL: 15.6 mm) obtained from experiment I were reared under culture conditions similar to those of experiment I, but at lower stocking densities (6, 10 and 15 larvae l−1). The fish were fed exclusively with artificial feed (trout starter) for 21 consecutive days. At densities of 6 and 15 larvae l−1, the growth rate and fish biomass gain ranged from 28.8 to 23.1 mg day−1 and from 2.0 to 3.3 g l−1, respectively. The highest survival (56.5%) was achieved at a density of 6 larvae l−1. Mortality at all densities was mainly caused by cannibalism II type behaviour (27–35% of total). In both experiments, growth and survival were negatively correlated and fish biomass gain positively correlated with stocking densities. The present study suggests that the initial stocking density of pikeperch larvae reared in a recirculating system can be 100 individuals l−1 for the 4- to 18-day period post-hatch and 15 individuals l−1 for the post-19-day period.  相似文献   

6.
The effect of prebiotic xylooligosaccharides (XOS) on the growth performance and digestive enzyme activities of the allogynogenetic crucian carp, Carassius auratus gibelio, was investigated. XOS was added to fish basal semi-purified diets at three concentrations by dry feed weight: diet 1, 50 mg kg−1; diet 2, 100 mg kg−1; diet 3, 200 mg kg−1, respectively. Twelve aquaria (n = 20) with three replicates for each treatment group (diets 1–3) and control treated without XOS were used. Weights of all collected carp from each aquarium were determined at the initial phase and at the end of the experiment, and the carp survival was also determined by counting the individuals in each aquarium. After 45 days, there were significant differences (P < 0.05) in the relative gain rate (RGR), and daily weight gain (DWG) of diets 1–3 were compared with the control. However, the survival rate was not affected (P > 0.05) by the dietary treatments. For enzymatic analysis, dissection produced a crude mixture of intestine and hepatopancreas of each segment to measure. The protease activity in the intestine and hepatopancreas content of fish in diet 2 (487.37 ± 20.58 U g−1 and 20.52 ± 1.93 U g−1) were significantly different (P < 0.05) from that in the control (428.13 ± 23.26 U g−1 and 12.81 ± 1.52 U g−1) and diet 3 (428.00 ± 23.78 U g−1 and 14.04 ± 1.59 U g−1). Amylase activity in the intestine was significantly higher for diet 2 compared to diet 1 and the control. As for amylase in the hepatopancreas, assays showed higher activity in diet 2 (P < 0.05) compared to the rest.  相似文献   

7.
Rainbow trout (Oncorhynchus mykiss) with a mean (sd) weight of 120 (2) g were fed diets supplemented with astaxanthin extracted from the yeast Phaffia rhodozyma (OY1 = 50 mg carotenoids kg–1 feed, OY2 = 100 mg carotenoids kg–1 feed), astaxanthin (AX = 100 mg astaxanthin kg–1 feed) and canthaxanthin (CX = 100 mg canthaxanthin kg–1 feed) for 4 weeks. Muscle analyses at the end of the experiment indicated a significantly higher carotenoid concentration in the AX group, while CX and OY1 groups were similar in spite of the differences in dietary concentration. The measure of total muscle colour difference (E* ab) between initial samples and 4 week ones was higher for the AX fish group but showed no significant difference between OY1, OY2, and CX. The hue and the reflectance ratio (R650:R510) of fish muscle increased in proportion to carotenoid intake. Digestibility (ADC) of yeast astaxanthin in OY1 and OY2 groups was significantly higher than that in the AX group. Canthaxanthin ADC was about one sixth of that of astaxanthin (AX group). Carotenoid retention in the muscle, expressed as a percentage of carotenoid intake, was higher for the AX group than that recorded for OY1 and OY2. According to ADC, carotenoid retention showed a marked lower value for the CX group. Muscle retentions were similar for astaxanthins from both sources.  相似文献   

8.
An eight-week feeding trial has been conducted to determine the optimum ration for Indian major carp, Labeo rohita, fingerling (4.10 ± 0.30 cm, 0.55 ± 0.16 g) by feeding a purified diet (40% CP; 3.61 kcal g−1 GE) at six levels, 2, 4, 6, 8, 10, and 12% of body weight per day, at 0800 and 1600 h, in triplicate, to 20 fish per trough fitted with a water flow-through system. Highest weight gain, best feed conversion ratio (FCR), best specific growth rate (SGR%), and highest protein efficiency ratio (PER) were evident for rations of 6–8% body weight. Second-degree polynomial regression analysis for FCR, PER, protein, and energy retention data indicated the break-points occurred at 6.55, 6.75, 6.80, and 6.95% bw per day, respectively. Significant (P < 0.05) differences between body composition were observed for fish fed different rations. Maximum body protein content was recorded for 6% and 8% rations. A linear increase in body fat content was evident with increasing ration. Body moisture and ash content remained non-significantly (P > 0.05) low for higher rations, however. On the basis of these results it is recommended that feeding in the range 6.5–7.0% bw per day corresponding to 2.6–2.8 g protein and 23.49–25.31 kcal energy per 100 g of the diet per day is optimum for growth and efficient feed utilization of Labeo rohita. Results for 2–4% rations (0.8–1.6 g protein and 7.23–14.46 kcal energy) suggest these amounts approximate to the maintenance requirement of this fish.  相似文献   

9.
An 8-week growth trial was conducted to assess the effect of dietary protein on growth, feed utilization, protein retention efficiency, and body composition of young Heteropneustes fossilis (10.02 ± 0.09 g; 9.93 ± 0.07 cm). Isocaloric (4.15 kcal g−1, GE) diets with varying levels of protein (25, 30, 35, 40, 45, and 50% of the diet) were fed near to satiation to triplicate groups of fish. Optimum dietary protein was determined by analyzing live weight gain (LWG%), feed conversion ratio (FCR), protein efficiency ratio (PER), specific growth rate (SGR%), and protein retention efficiency (PRE%) data. Maximum LWG% (167), best FCR (1.42), PER (1.75), SGR (1.76), and PRE (31.7%) were evident in fish fed 40% protein diet (Diet 4). Body protein data also supported the above level. However, second-degree polynomial regression analysis of the above data indicated that inclusion of dietary protein in the range of 40–43% is optimum for the growth of young H. fossilis.  相似文献   

10.
Three 2‐factor experiments were conducted to determine the effects of background colour and synthetic carotenoids on the skin colour of Australian snapper Pagrus auratus. Initially, we evaluated the effects on skin colour of supplementing diets for 50 days with 60 mg kg?1 of either astaxanthin (LP; Lucantin® Pink), canthaxanthin (LR; Lucantin® Red), apocarotenoic acid ethyl ester (LY; Lucantin® Yellow), selected combinations of the above or no carotenoids and holding snapper (mean weight=88 g) in either white or black cages. In a second experiment, all snapper (mean weight=142 g) from Experiment 1 were transferred from black to white, or white to white cages to measure the short‐term effects of cage colour on skin L*, a* and b* colour values. Skin colour was measured after 7 and 14 days, and total carotenoid concentrations were determined after 14 days. Cage colour was the dominant factor affecting the skin lightness of snapper with fish from white cages much lighter than fish from black cages. Diets containing astaxanthin conferred greatest skin pigmentation and there were no differences in redness (a*) and yellowness (b*) values between snapper fed 30 or 60 mg astaxanthin kg?1. Snapper fed astaxanthin in white cages displayed greater skin yellowness than those in black cages. Transferring snapper from black to white cages increased skin lightness but was not as effective as growing snapper in white cages for the entire duration. Snapper fed astaxanthin diets and transferred from black to white cages were less yellow than those transferred from white to white cages despite the improvement in skin lightness (L*), and the total carotenoid concentration of the skin of fish fed astaxanthin diets was lower in white cages. Diets containing canthaxanthin led to a low level of deposition in the skin while apocarotenoic acid ethyl ester did not alter total skin carotenoid content or skin colour values in snapper. In a third experiment, we examined the effects of dietary astaxanthin (diets had 60 mg astaxanthin kg?1 or no added carotenoids) and cage colour (black, white, red or blue) on skin colour of snapper (mean weight=88 g) after 50 days. Snapper fed the astaxanthin diet were more yellow when held in red or white cages compared with fish held in black or blue cages despite similar feed intake and growth. The skin lightness (L* values) was correlated with cage L* values, with the lightest fish obtained from white cages. The results of this study suggest that snapper should be fed 30 mg astaxanthin kg?1 in white cages for 50 days to increase lightness and the red colouration prized in Australian markets.  相似文献   

11.
An experiment was conducted to investigate the effect of dietary chromium picolinate supplement on growth and haematology parameters of grass carp, Ctenopharyngodon idellus. Six diets with increasing dietary chromium picolinate levels 0, 0.2, 0.4, 0.8, 1.6 and 3.2 mg kg−1 were fed to triplicate groups of 20 fish (initial weight of 12.78 ± 1.16 g, mean ± SD) in a flow water system for 10 weeks. Fish fed the diet supplemented with 0.8 mg Cr kg−1 had significantly improved weight gain (WG), feed efficiency ratio (FER), protein efficiency ratio (PER) and protein retention (PR). Fish fed high-chromium diets exhibited lower whole-body crude lipid contents than fish fed low-chromium diets. Liver glycogen concentrations for fish fed the diet with 0.2 mg Cr kg−1 was the highest (77.67 mg g−1). Fish fed the diet supplemented with 1.6 and 3.2 mg Cr kg−1 had significantly lower liver glycogen concentrations than other groups (P < 0.05). The highest serum insulin concentrations were observed in fish fed the diet supplemented with 0.8 mg Cr kg−1, but serum insulin concentrations decreased (P < 0.05) when dietary supplementation of chromium was higher than 0.8 mg Cr kg−1. Cholesterol concentrations decreased in direct proportion to dietary chromium level and achieved the lowest level when the fish were fed the 0.8 mg Cr kg−1 diet, but increased when the fish were fed the diet with more than 0.8 mg Cr kg−1 (P < 0.05). Fish fed the diet supplemented with 0.8 mg Cr kg−1 had higher triglyceride and high-density lipoprotein cholesterol (HDL-C) concentrations compared to other treatments. The results of the present study suggested that chromium picolinate could modify serum carbohydrate and lipid metabolism profile, and that the optimal dietary chromium level was 0.8 mg kg−1 for grass carp according to growth.  相似文献   

12.
The characteristic pink colour of salmonid flesh is a result of deposition of naturally occurring carotenoid pigments. Achieving successful pigmentation in farmed salmonids is a vital aspect of fish farming and commercial feed production. Currently commercial diets for farmed salmonids contain either or both of the synthetic pigments commercially available, astaxanthin and canthaxanthin. Atlantic salmon, Salmo salar L. ( = 220 g initial weight) were given feeds where the pigment source was astaxanthin only, canthaxanthin only or a astaxanthin/canthaxanthin mix. The rearing environment was 12 × 3 m tanks supplied with sea water at the EWOS research farm Lønningdal, near Bergen, Norway. As the proportion of dietary canthaxanthin increased, flesh pigment levels also showed an increase; the pigment content in the muscle of canthaxanthin‐only fed fish was 0.4 mg kg?1 (or 14%) higher than that of the astaxanthin‐only fed fish, with the mixed pigment fed fish being intermediate between the two extremes. Results of cross‐section assessment for Minolta colorimeter redness (a*) values and Roche SalmofanTM scores also showed an increase in colour with increasing proportions of canthaxanthin in the feed. The data reported clearly indicates that S. salar ( = 810 g final weight) of this size deposit canthaxanthin more efficiently than they do astaxanthin. These results contrast with those obtained by other authors with rainbow trout, Oncorynchus mykiss (Walbaum), and imply that the absorption or utilization of the pigments differs between species.  相似文献   

13.
Gastrointestinal and metabolic influences on short- and medium-term control of voluntary feed intake of European eel were investigated for groups of fish fed at different feeding schedules: 1 meal 2 days−1, 1 meal day−1, 2 meals day−1 and continuous feeding for 12 h and 24 h daily. For fish fed daily, the feeding schedule had no effect on feed intake, metabolism, growth, size variation and body composition. Only fish fed once every 2 days could not completely compensate by increasing their average meal size and showed a reduced feed intake, metabolism and growth. Stomach capacity did not limit meal size and feed intake as large differences in appetite were found for eels with empty stomachs. Feed intake was related to metabolism as the levels of O2 consumption and NH4 excretion just before the meal were correlated to average meal size, suggesting that rate (and duration) of metabolism is sensed and is providing information about the metabolic consequences of feed intake and feed processing. Meal size is based on the (expected) scope for metabolism and eels seem to strive to an average daily feed intake, associated with their developmental state (growth potential). Plasticity in this feed intake behaviour, expressed by individual variation in feed intake and day-to-day fluctuations in individual and group intake, is regarded as adaptive on different time scales.  相似文献   

14.
Pyridoxine is essential for animals. The purpose of this study was to investigate the pyridoxine deficiency symptoms and the fit dose of pyridoxine to keep normal physiological function in grouper, Epinephelus coioides. Graded levels of pyridoxine (0, 1, 2, 4, 8, 16, 32 mg pyridoxine kg−1 diet) were fed to grouper juveniles (14.83±0.31 g) for 8 weeks, and then some physiological and biochemical parameters were measured. Pyridoxine deficiency symptoms such as anorexia, poor survival, convulsion, helically swimming and hyperirritability were observed in fish fed the pyridoxine-deficient diet, and these fish also showed low whole blood haemoglobin level, liver glutamic-pyruvic transaminase (GPT) and superoxide dismutase (SOD) activities. Slight symptoms of pyridoxine deficiency also appeared among fish fed the diet with very low dose (1 mg pyridoxine kg−1 diet) of pyridoxine in 6 weeks. Broken-line regression analysis showed that the optimal pyridoxine levels for these fish to keep normal survival, whole blood haemoglobin level, liver GPT and SOD activities were approximately 1.75, 1.87, 2.22 and 2.05 mg kg−1, respectively.  相似文献   

15.
Two experiments were conducted with Australian snapper Pagrus auratus (Bloch and Schneider, 1801). The first was aimed at determining the dietary level of astaxanthin that improved skin redness (CIE a*values) of farm‐reared snapper. Farmed snapper (ca. 600 g) fed a commercial diet without carotenoids were moved to indoor tanks and fed the same diet supplemented with 0, 36 or 72 mg astaxanthin kg?1 (unesterified form as Carophyll Pink?) for nine weeks. Skin redness (CIE a* values) continued to decrease over time in fish fed the diet without astaxanthin. Snapper fed the diet containing 72 mg astaxanthin kg?1 were significantly more red than fish fed the diet with 36 mg astaxanthin kg?1 three weeks after feeding, but skin redness was similar in both groups of fish after 6 and 9 weeks. The second experiment was designed to investigate the interactive effects of dietary astaxanthin source (unesterified form as Carophyll Pink? or esterified form as NatuRose?; 60 mg astaxanthin kg?1) and degree of shading (0%, 50% and 95% shading from incident radiation) on skin colour (CIE L*a*b*) and skin and fillet astaxanthin content of farmed snapper (ca. 800 g) held in 1 m3 floating cages. After 116 days, there were no significant interactions between dietary treatment and degree of shading for L*, a* or b* skin colour values or the concentration of astaxanthin in the skin. Negligible amounts of astaxanthin were recovered from fillet samples. The addition of shade covers significantly increased skin lightness (L*), possibly by reducing the effect of melanism in the skin, but there was no difference between the lightness of fish held under either 50% or 95% shade cover (P>0.05).  相似文献   

16.
A 60-days feeding trial was conducted to delineate the effect of both gelatinized and non-gelatinized corn with or without supplementation with exogenous α-amylase at two dietary protein levels (35% and 28%) on dry matter digestibility, digestive enzymes and tissue glycogen content of Labeo rohita juveniles. Three hundred and sixty juveniles (average weight 10±0.15 g] were randomly distributed into 12 treatment groups with each of two replicates. Twelve semi-purified diets containing either 35% or 28% crude protein were prepared by including gelatinized (G) or non-gelatinized (NG) corn as carbohydrate source with different level of microbial α-amylase (0, 50, 100 and 150 mg kg−1). The dry matter digestibility of G corn fed groups was significantly higher (P < 0.05) than that of the NG corn fed groups. Hepatosomatic index (HSI), liver glycogen and intestinal amylase activity of G starch fed groups were significantly higher (P < 0.05) than those of the NG corn fed groups. However, the reverse trend was found for gastrosomatic index (GSI), muscle glycogen and intestinal protease activity. Addition of 50 mg α-amylase kg−1 feed improved the dry matter digestibility of NG starch fed groups, which was similar to that of the G corn fed groups or NG corn supplemented with 100/150 mg α-amylase kg−1 feed. HSI, liver glycogen and intestinal amylase activity were significantly increased (P < 0.05) at minimum level of α-amylase in the feed (50 mg kg−1) and did not increase due to further inclusion of amylase in the diet. Supplementation with α-amylase at 50 mg kg−1 increased the intestinal amylase activity beyond which no significant changes were observed. Protease activity of liver and intestine was highest (P < 0.05) in higher crude protein (CP) fed groups, but protease activity of the intestine was significantly higher in the α-amylase supplemented groups. Hence, it was concluded that feed with 28% CP containing either G corn without α-amylase or NG corn with 50 mg α-amylase kg−1 may be used as the alternative carbohydrate source for L. rohita juveniles.  相似文献   

17.
This study was undertaken to assess dorsal aorta cannulation as a method to evaluate alterations in diet composition and feeding protocol on pigment retention in salmonid fish. Temporal changes in blood astaxanthin concentrations of dorsal aortacannulated Atlantic salmon, Salmo salar L., were followed in relation to variations in dietary pigment concentration and fish-feeding husbandry protocol. The fish were held individually in 200-L fibreglass tanks supplied with running sea water. Each fish was forced to swim at 0.5 body lengths s?1 and was fed daily by hand to satiation. The fish had an average growth rate of 1% day?1. Blood astaxanthin concentrations were noted to be highly correlated (r= 0.995) with dietary levels of astaxanthin, but not as well correlated (r= 0.71) with total gut content of this pigment. Marked variations in blood astaxanthin concentration were noted between individual fish at each dietary pigment concentration, but the ranking of the fish was generally unaffected between each dietary pigment level. After cessation of feeding a diet supplemented with 75 mg of astaxanthin kg?1, salmon fed a diet with no pigment showed more-rapid blood pigment clearance than those that were starved. Likely, feed remaining in the alimentary tract of the starved fish functioned as a reservoir of pigment for the blood until the intestinal tract was empty. Blood pigment levels were not depressed in salmon fed a diet supplemented with 75 mg of astaxanthin kg?1 once daily instead of twice daily.  相似文献   

18.
Asian catfish, Clarias batrachus, were fed semi-purified basaldiets containing 0, 0.1, 0.5, 1, 3 and 5 mg biotin kg–1diet for 60 days. Fish fed the control diet (no biotin) showed(P < 0.05) higher mortality, lower weight gain, specificgrowth rate (SGR), feed efficiency ratio (FER) and protein efficiencyratio (PER) than in fish fed diets supplemented with biotin. The highestweight gain, SGR, FER and PER were noticed in fish fed 1 mg biotinkg–1, followed by 0.5, 5, 3 and 0.1 mg biotinkg–1, except for PER (followed by 0.5, 5, 0.1 and 3 mgbiotin kg–1). Quadratic analysis showed that the optimumdietary biotin requirements for maximal weight gain, PER and PER were2.49, 2.54 and 2.52 mg kg–1, respectively. Liver biotinconcentrations were influenced by levels of biotin in the diet.Concentration of liver biotin increased as level of dietarysupplementation increased and no biotin was detected in the liver of thecontrol fish. Liver pyruvate carboxylase and acetyl CoA carboxylaseactivities were higher in fish fed biotin-supplemented diets than incontrols. Biotin concentrations, pyruvate carboxylase and acetyl CoAcarboxylase activities in liver associated with normal growth rangedfrom 10.59 to 10.66 g g–1, 147.97 to 148.18 units mgprotein–1 and 12.76 to 12.78 units mg protein–1, respectively. Biotin deficiency symptoms such as anorexia, darkskin colour and convulsions were observed in fish fed the control diet.The optimum dietary biotin requirement for maximal growth of C.batrachus is about 2.49 mg kg–1 diet.  相似文献   

19.
A single‐factor experiment was conducted to investigate the effects of dietary astaxanthin concentration on the skin colour of snapper. Snapper (mean weight=129 g) were held in white cages and fed one of seven dietary levels of unesterified astaxanthin (0, 13, 26, 39, 52, 65 or 78 mg astaxanthin kg?1) for 63 days. Treatments comprised four replicate cages, each containing five fish. The skin colour of all fish was quantified using the CIE L*, a*, b* colour scale after 21, 42 and 63 days. In addition, total carotenoid concentrations of the skin of two fish cage?1 were determined after 63 days. Supplementing diets with astaxanthin strongly affected redness (a*) and yellowness (b*) values of the skin at all sampling times. After 21 days, the a* values increased linearly as the dietary astaxanthin concentration was increased before a plateau was attained between 39 and 78 mg kg?1. The b* values similarly increased above basal levels in all astaxanthin diets. By 42 days, a* and b* values increased in magnitude while a plateau remained between 39 and 78 mg kg?1. After 63 days, there were no further increases in measured colour values, suggesting that maximum pigmentation was imparted in the skin of snapper fed diets >39 mg kg?1 after 42 days. Similarly, there were no differences in total carotenoid concentrations of the skin of snapper fed diets >39 mg kg?1 after 63 days. The plateaus that occurred in a* and b* values, while still increasing in magnitude between 21 and 42 days, indicate that the rate of astaxanthin deposition in snapper is limited and astaxanthin in diets containing >39 mg astaxanthin kg?1 is not efficiently utilized. Astaxanthin retention after 63 days was greatest from the 13 mg kg?1 diet; however, skin pigmentation was not adequate. An astaxanthin concentration of 39 mg kg?1 provided the second greatest retention in the skin while obtaining maximum pigmentation. To efficiently maximize skin pigmentation, snapper growers should commence feeding diets containing a minimum of 39 mg unesterified astaxanthin kg?1 at least 42 days before sale.  相似文献   

20.
The substrate specificity of brain acetylcholinesterase (AChE) in adult Carassius auratus fish and its sensitivity to carbamate insecticides were investigated in vitro. The results showed that the order of four substrates hydrolyzed by brain AChE in C. auratus was acetylthiocholine iodide > β-methylthiocholine iodide > propionylthiocholine iodide > butyrylthiocholine iodide, and the maximum velocity (V max) of AChE hydrolyzing acetylthiocholine iodide (ATCh) was the highest among the four substrates, and the V max values were 0.067 and 0.082 mmol min−1 mg−1 for male and female fish respectively. But their Michaelis–Menten constants (K m) were the lowest, only 0.071 and 0.072 mmol/l respectively. Compared with other carbamate insecticides, the sensitivity of brain AChE to carbofuran was the highest and the IC50 values were 1.04 × 10−6 mol/l for females and 1.17 × 10−6 mol/l for males. The inhibitory tendencies of eserine, methomyl, and aldicarb to brain AChE were very similar, and the percentage inhibition increased with time at the concentration of 1 × 10−6 mol/l. The order of inhibition potential of the three inhibitors from the highest to the lowest was eserine, aldicarb, and methomyl.  相似文献   

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