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1.
Effects of dietary protein level and water salinity on spawning performance of Nile tilapia broodstock and growth of their larvae were studied. Four isocaloric (400 kcal/100 g) diets containing 25%, 30%, 35% and 40% crude protein were prepared. The diets were fed to broodfish (25.7 g) reared at three water salinities (0‰, 7‰ and 14‰) at a female/male ratio of 3:1, to satiation twice a day for 195 days. The size at first maturation increased with increasing dietary protein at all salinities. At 25% and 30% protein levels, broodstock reared at 0‰ reached their sexual maturity at bigger sizes than those reared at 7‰ and 14‰. At 0‰, spawning intervals were not significantly affected by dietary protein levels. At 7‰ and 14‰, spawning intervals significantly decreased with increasing dietary protein level. Spawning frequency and number of eggs per spawn were increased with increasing dietary protein level. The total number of spawnings per female and absolute fecundity were better in fish fed 40% protein in freshwater than at 7‰ and 14‰ salinity. The relationship of dietary protein and water salinity on egg size was significant, but showed irregular patterns. The chemical composition of broodstock muscles, eggs and fry were not significantly affected by dietary protein and water salinity, except for body water and crude protein of broodstock which were significantly affected; but showed irregular trends. At each water salinity, egg hatchability was linearly increased with increasing dietary protein level. Eggs produced from broodstock fed 25% protein at 7‰ and 14‰ needed more time for hatching and yolk-sac absorption and resulted in poorer larval weight than those reared in freshwater. Fry growth was improved with increasing protein level at all salinities. This result revealed that 40% dietary protein is required for optimum spawning performance of Nile tilapia reared at 0‰, 7‰ and 14‰ salinity. It also indicated that spawning performance and larval growth were better in freshwater than at 7‰ and 14‰.  相似文献   

2.
The effects of dietary protein and energy level on spawning performance of Nile tilapia broodstock and hatchability of their eggs were studied. Nine diets containing three protein (30, 35 and 40%) and three energy (14.6, 16.7 and 18.8 MJ GE/kg) levels were prepared. The diets were fed to duplicate groups of broodfish (average weight of 60.5 ± 4.6 g for males and 39.4 ± 3.1 g for females) at 2–3% of their body weight, twice a day, for 150 days. At low protein level (30%), time to first spawning was significantly longer than at 35 and 40% protein levels, and increased with increasing dietary energy (decreasing protein-to-energy (P/E) ratio). At 35 and 40% protein levels, time to first spawning was not affected by dietary energy. Inter-spawning intervals (ISI) showed irregular patterns in relation to dietary protein and energy, however, at 40% protein the females tended to spawn at shorter intervals, regardless of dietary energy. Spawning performances, including total number of spawnings per tank, number of spawnings per female, absolute fecundity and average number of eggs per spawn, were all significantly lower (P < 0.05) at 30% CP than at higher protein levels. At all protein levels, increasing dietary energy from 14.6 to 18.8 MJ GE/kg (and decreasing P:E ratio) resulted in a significant decrease in fish fecundity. Egg size was not significantly affected by dietary protein and energy. At all energy levels, egg hatchability increased with increasing dietary protein levels (P < 0.05). Eggs produced from broodstock fed 30 and 35% CP, exhibited significantly lower hatchability (P < 0.05) and needed less time for hatching and yolk-sac absorption, and resulted in lower larval length than those fed a 40% protein diet. However, increasing energy level at each dietary protein level did not significantly affect these parameters. These results revealed that the best spawning performance of Nile tilapia broodstock reared in a recycling system was achieved at 40% dietary protein and 16.7 MJ GE/kg, with a P/E ratio of 23.6 g/MJ.  相似文献   

3.
This study was conducted to investigate the effects of maternal inherited immunity acquired from crustacean‐enhanced diets on the vitality and profitability of sea bass offspring. Newly hatched larvae produced from three groups of broodstock were evaluated. The broodstock were fed (a) a basal diet (BD), (b) a Palaemon‐supplemented diet (PSD), and (c) an Artemia‐supplemented diet (ASD) for 42 days. A total of 400,000 larvae at 3 days posthatch (DPH) produced from each treatment were stocked in larval rearing tanks at 40 larvae/L for 42 days. Survival (%) was improved by 37 and 9.96% in the groups fed ASD and PSD compared with the control group. The growth, swim bladder (%), and condition factor all significantly (p ≤ 0.05) improved in the postlarvae produced from broodstock enhanced with crustacean diets. Compared with the BD group, the serum lysozyme activities of the fish groups fed ASD and PSD increased by 45.6 and 11.7%, respectively. Sea bass fry (90DPH) produced from broodstock fed ASD showed the best tolerance to salinity/temperature stress tests. Furthermore, the profitability improved in ASD and PSD compared with the BD group. In conclusion, sea bass broodstock enhanced with Artemia biomass produced offspring of superior quality with less cost and greater profit margins.  相似文献   

4.
This study was conducted to determine the effects of dietary highly unsaturated fatty acids (HUFA) on flame angelfish (Centropyge loriculus) reproduction, and egg and larval quality. In the experiment, formulated diets containing 1.8, 2.9 or 3.6% n‐3 HUFA were fed to flame angelfish broodstock (n = 4) for 5 months. Mean fecundity (daily egg production), egg fertilization rates and embryo viability were used as indicators of egg quality. In addition, mean egg diameter, oil globule diameter, per cent hatch, larval size at hatch, per cent survival to yolk exhaustion and larval size at yolk exhaustion were recorded for each treatment. Flame angelfish fed the diet containing 3.6% n‐3 HUFA exhibited significantly increased fecundity, fertilization rates and embryo viability than fish that were fed the other two formulated diets. Egg diameter, egg oil globule diameter, larval size at hatch, larval survival to yolk exhaustion and larval size at yolk exhaustion from the 3.6% n‐3 HUFA broodstock treatment group were not significantly different from those derived from the Control broodstock treatment. These data revealed that flame angelfish egg quality could respond rapidly (within weeks) to maternal dietary changes. Results from this study further support that dietary HUFA composition can significantly affect broodstock reproductive performance as well as subsequent performance of eggs and larvae.  相似文献   

5.
The effect of increasing levels of dietary phospholipids (PL) on the ovarian development and reproductive performance of Chinese mitten crab Eriocheir sinensis were investigated using four semipurified formulated diets supplemented with 0%, 1.2%, 2.4%, and 3.6% PL. Four groups of 40 females, with an average individual body weight of 95–120 g, were fed the experimental diets for a period of 7 months. Male crabs were introduced into the female rearing system in March, and mating, spawning, and egg hatching occurred in the following month. After 10 weeks of feeding, females fed the diet with 2.4% PL had a significantly higher gonadosomatic index (GSI) than females fed the diet with 0% PL, whereas females fed the diet with 1.2% PL had a significantly higher hepatic moisture content and lower hepatic lipid content than the other groups (P < 0.05). After mating, the spawning rate was higher among females fed diets with 3.6% and 2.4% PL (95% and 92%, respectively) compared with females fed diets with 0% and 1.2% PL (both 81%). The results showed that egg production (total number of eggs/female) and fecundity increased with increasing dietary PL level, with females fed diets with 0% and 1.2% PL supplementation having significantly lower values than females fed the diet with 3.6% PL (P < 0.05). In conclusion, our results suggest that dietary PL supplementation has a positive effect on ovarian development and reproductive performance of E. sinensis broodstock. Further study should aim to investigate the optimal PL level in the broodstock diet of E. sinensis in respect to offspring quality.  相似文献   

6.
This study investigated the effect of two lipid sources on reproduction performance and growth in pearl gourami. For this purpose, 180 fish (3.32 ± 0.25 g) were fed with three isoenergetic (19.80) and isonitrogenous diets (480 g/kg protein) including FO (80 g/kg fish oil), FS (40 g/kg fish oil and 40 g/kg soybean oil) and SO (80 g/kg soybean oil) for 10 weeks before maturation. At the end of the trial, there was no significant difference in weight gain, feed conversation ratio and body composition between fish fed FO and FS diets. Individuals fed dietary FO had significantly higher levels of n‐3 long‐chain polyunsaturated fatty acids in the muscle (130.5 g/kg lipid) and ovary (140.4 g/kg lipid) as compared with those fed SO diet (64.5, 103.6 g/kg, respectively) (p < .05). Feeding pearl gourami with FO and FS diets enhanced regarding absolute fecundity, relative fecundity, the fertilization rate, larvae total length and survival at 3 day posthatch (p < .05). Also, 17 beta‐estradiol in plasma of fish fed dietary FO (6.2 ng/L) was higher than those fed SO diet (1.7 ng/L) (p < .05). In conclusion, we suggest FS diet for broodstock nutrition of pearl gourami as a model for asynchronous multi‐batch spawning fish.  相似文献   

7.
The effects of increasing levels of dietaryphospholipids (PL) on the reproductive performance,egg and larval quality, and lipid composition offemales of the freshwater prawn Macrobrachiumrosenbergii were investigated. Three isolipidic dietscontaining similar amounts of highly unsaturated fattyacids but varying levels of PL (0.8, 2.4 and 4.6%)were fed during 180 days to three groups of eightfemales originating from Thai ponds. No significantdifferences were observed for fecundity, egg size andhatchability, starved larvae size, and size, survivaland tolerance to stress of 8 day-old larvae.Similarly, no major differences in the lipidcomposition of the midgut gland, ovaries and muscletissue of females could be detected. Results indicatethe lack of need of dietary supplementation of PL forM. rosenbergii broodstock, as previouslyreported for earlier life stages. It is suggested thatthe basal level of 0.8% dietary PL was sufficient tomeet the dietary demands of the prawn broodstock. ThePL requirements of M. rosenbergii broodstock, ifany, may be satisfied in commercial feeds through theinclusion of ingredients containing some phospholipidsendogenously.  相似文献   

8.
The effects of formulated feeds on Paracentrotus lividus broodstock performances and carotenoid compositions were investigated. Performance of offspring derived from each dietary treatment was compared to determine whether maternal provisioning of nutrients affected offspring development and survival under commercial culture conditions. At the end of the experimental period (3 months), urchins were induced to spawn, relative fecundity measured, and offspring derived from each treatment were reared independently and survival up to competence assessed. Carotenoid composition of the gonads was also measured. Data showed that the highest dietary protein content significantly improved somatic growth, whereas higher lipid content increased gonadal index (GI) consistent with the use of gonads as nutrient storage in sea urchins. Nonetheless, gonad lipid concentration was not significantly different between treatments indicating that higher dietary lipid content favoured gonadal size rather than increase lipid content of the gonadal tissue. Interestingly, GI and fecundity were not correlated, although the latter may have been enhanced by dietary xanthophyll. This suggests the importance of including carotenoids in broodstock diets to enhance hatchery outputs. This study also indicated that, although broodstock diet can influence fecundity, it had no significant impact on larval survival, which could instead be influenced by rearing conditions.  相似文献   

9.
An 8-week feeding experiment was conducted to investigate the effects of different dietary macronutrient level and feeding frequency on the growth, feed utilization, and body composition of juvenile rockfish. Triplicate groups of fish (body weight of 4.1 g) were fed the experimental diets containing either high levels of carbohydrate (HC, 35%), lipid (HL, 13%), or protein (HP, 55%) at different feeding frequencies (twice daily, once daily, and once every 2 days). Weight gain was affected by feeding frequency but not by dietary composition. Weight gain of fish fed the diets once every 2 days was significantly (P < 0.05) lower than that of other groups. Daily feed intake and energy intake were affected by both dietary composition and feeding frequency. Daily feed intake of fish fed the HC diet was significantly (P < 0.05) higher than that of fish fed the HL and HP diets at the same feeding frequency. Feed efficiency and protein efficiency ratio were affected by both dietary composition and feeding frequency and decreased with increasing feeding frequency in the same dietary composition. Feed efficiency and protein efficiency ratio of fish fed the HC diet were significantly (P < 0.05) lower than those of fish fed the HL diet at the same feeding frequency. Whole-body lipid content of fish fed the HL diet was significantly (P < 0.05) higher than that of fish fed the HC and HP diets at the same feeding frequency. These results indicate that an increase of dietary lipid level compared with dietary carbohydrate level may have the advantage of a protein-sparing effect at same feeding frequency, and a once-daily feeding regime is more effective than twice daily or one feeding every 2 days to improve growth performance of juvenile rockfish grown from 4 to 21 g.  相似文献   

10.
研究了牛磺酸对半滑舌鳎(Cynoglossus semilaevis Günther)亲鱼繁殖性能、抗氧化功能、卵子及仔鱼质量的影响。在基础饲料中分别添加0、0.5%、1.5%的牛磺酸,配制3组(对照组T-0、T-0.5、T-1.5)等氮等脂的配合饲料,在室内流水养殖系统进行为期63 d的养殖实验。研究结果显示,在饲料中添加0.5%牛磺酸,不仅能够提高半滑舌鳎亲鱼的相对产卵量,还能促进亲鱼体内睾酮和雌二醇的分泌(P<0.05);T-0.5组浮卵率、受精率、孵化率、卵径、油球直径、3日龄、7日龄仔鱼体长均显著高于对照组(P<0.05),T-0.5组和T-1.5组仔鱼畸形率显著低于对照组(P<0.05);3个实验组仔鱼生存活力指数(SAI)无显著性差异(P>0.05);饲料中添加牛磺酸能够提高其肝脏和性腺中牛磺酸含量,降低肝脏中半胱胺双加氧酶活性;T-0.5组肝脏、血清、精巢、精液中超氧化物歧化酶(SOD)活性显著高于对照组(P<0.05),性腺和卵子中丙二醛(MDA)含量显著低于对照组(P<0.05)。研究结果表明,饲料中添加牛磺酸能够提高半滑舌鳎亲鱼繁殖性能、抗氧化功能、卵子及仔鱼质量。在本研究条件下,牛磺酸含量为0.5%的饲料组为最佳饲料组。  相似文献   

11.
Despite carotenoids and essential fatty acids seem to play important roles in fish reproduction, no studies have yet been conducted to determine the effect of dietary carotenoids on gilthead seabream broodstock performance and their relation as antioxidants with dietary n‐3 highly unsaturated fatty acid (HUFA) levels. In addition, the high cost of synthetic sources of carotenoids is leading to the search for new natural carotenoid sources such as paprika oleoresin. Four experimental diets containing two combined levels of carotenoids from paprika oleoresin (40 and 60 mg kg?1) and n‐3 HUFA (25 and 40 g kg?1) were respectively fed to triplicate groups of gilthead seabream (Sparus aurata) broodfish. Elevation of n‐3 HUFA dietary levels from 25 to 40 g kg?1 significantly improved gilthead seabream broodstock performance in terms of egg viability, hatching rates and fecundity. Besides, it markedly increased egg contents in HUFAs which play important energetic and structural roles and improve embryo development. Both arachidonic acid and eicosapentaenoic acid (20:5n‐3) egg contents were more readily affected by dietary n‐3 HUFA than docosahexaenoic acid. HUFA levels did not caused any negative effect suggesting an optimized content of antioxidants in broodstock diets. Increase in dietary carotenoids from 40 to 60 mg kg?1 increased carotenoid contents in eggs and significantly improved egg fertilization rates suggesting an important sperm cell’s protective role by reducing the risk of lipid peroxidation which is detrimental for sperm motility. The increased inclusion of dietary paprika oleoresin enhanced egg carotenoid deposition and improved fish reproductive performance, denoting the high nutritional value of this product as a source of carotenoids for broodstock of this species.  相似文献   

12.
Adult black sea bass Centropristis striata broodstock ( N =162) were fed three different dietary treatments: two commercially prepared diets with 45% protein and two different lipid levels (12% and 20%) (diets 1 and 2), and a diet of frozen Atlantic silversides Menidia menidia (SS, diet 3). Broodstock were held under controlled photothermal conditions and induced to spawn with an LHRHa pellet (72 μg kg−1 bw). Dietary lipid had pronounced effects on spawning performance and egg quality. Diet 3 (SS) produced a significantly ( P <0.05) higher fertilization success (22.4%) than diets 1 (0.6%) and 2 (4.8%). The hatching success of fertilized eggs was similar in all diets (range=40–58.6%), but only two spawns from diet 1 (12% lipid) yielded viable yolk-sac larvae (YSL). Diet 3 (SS) also produced significantly more YSL per female (21.8 × 103) than the diet 1 (0.3 × 103). Eggs from diet 3 (SS) contained a significantly greater proportion of n-3 series fatty acids, with docosahexaenoic acid (DHA) as the largest fraction. Eggs from commercially prepared dietary treatments contained significantly more n-6 fatty acids. The poor spawning performance of fish fed diet 1 (12% lipid) may be related to higher levels of linoleic acid and lower levels of DHA in the diet.  相似文献   

13.
The effect of feeding four semi‐purified diets A1, A2, A3, A4, containing different vitamin A acetate levels 0, 20, 40, 60 mg kg?1 diet, respectively, on fecundity, egg hatching rate, larval survival rate and vitamin A content in eggs of Chinese shrimp (Penaeus chinensis) broodstock was compared with a fresh clam diet (control) in a 60‐day feeding trial. The broodstock shrimp fed the diet with 60 mg kg?1 vitamin A acetate added exhibited significantly higher fecundity (P < 0.01). Hatching rate was highest with diet A4 (P < 0.05), whereas hatching rates were similar fed diets A1, A2, A3. Increasing levels of vitamin A in broodstock diet resulted in improvement in larval quality. The vitamin A levels in shrimp eggs from broodstock fed with diet A4 were higher compared with those from broodstock fed with diet A1, A2 (P < 0.01). The fecundity and hatching percentages were positively correlated with the vitamin A content in eggs in the present study. The results of this study showed that higher level of vitamin A in broodstock diet may have positive effects on fecundity and larval quality in P. chinensis.  相似文献   

14.
We investigated the effect of high levels of n−3 highly unsaturated fatty acids (n−3 HUFA) in broodstock diet on egg quality and chemical composition of eggs of Japanese flounder. The broodstock were fed diets containing three levels of n−3 HUFA (2.1%, 4.8% or 6.2%) 2 months before and during the spawning period. No significant difference was found for weight gain of broodstock among the treatments. Egg production was highest in fish fed the highest level of n−3 HUFA. However, egg quality parameters, such as percentage of buoyant eggs, hatching rate and percentage of normal larvae, were significantly higher in the group fed the lowest n−3 HUFA diet. The fatty acid composition of eggs was influenced more markedly in the neutral lipid fraction than in the polar lipid fraction by dietary n−3 HUFA levels. Arachidonic acid (AA; 20:4n−6) and egg quality parameters both decreased with increasing dietary n−3 HUFA levels. The results suggest that a high level of n−3 HUFA in broodstock diet negatively affects egg quality of Japanese flounder.  相似文献   

15.
This study investigates the dietary arachidonic acid (ARA) requirement from juvenile to maturation stage in an anabantid model fish, the blue gourami, Trichopodus trichopterus. Specifically we determined the optimum dietary ARA content to maximize juvenile growth and subsequent sexual maturation and to improve the quality of their eggs and offspring. Five experimental diets containing 0.02, 0.53, 1.05, 1.60, and 2.12% ARA (of dry weight) were fed to juveniles over 5 mo. The results showed that whole‐body fatty acid profile of broodstock significantly changed in fish fed diets of different ARA content (ANOVA, P < 0.003). The highest contents of 18:2n‐6 and Σn‐6 were obtained in fish fed 0.53% ARA, and a decreasing trend was observed with elevated dietary ARA levels. Monthly specific growth rate (SGR) measurements revealed significant differences in the juvenile stage, but the SGR of broodstock was unaffected by dietary ARA. Protein and ash content of whole‐body broodstock showed no differences among groups, while lipid content decreased as ARA levels increased. Maximum volume of the oocyte was obtained in the 1.05% ARA group, while the yolk sac size increased as dietary ARA increased. The optimum growth and survival of the larvae produced by broodstock were recorded in the 2.12 and 1.6% ARA groups, respectively. It was concluded that despite the presumed ability of freshwater fish to synthesize and meet their highly unsaturated fatty acid requirements, dietary ARA higher than 1.05% had significant stimulatory effects on growth of juveniles but no obvious influence on the growth of matured fish. Also, higher ARA levels (1.6–2.12%) were found to improve the quality of eggs and offspring.  相似文献   

16.
Juvenile Colossoma macropomum were fed ad libitum diets containing either 30% or 40% protein, while the dietary lipid level varied between 5% and 20%. Growth and protein utilization efficiency increased with the dietary lipid level. However, the economic feasibility of the addition of extra dietary lipid to C. macropomum diets is questionable, as for every extra gram of protein deposition it was necessary to replace 20–25 g of dietary carbohydrates by lipids. Moreover, increased dietary lipid levels resulted in increased lipid deposition. In C. macropomum, feed uptake was regulated by the dietary protein level and unaffected by the dietary lipid level. Dissection of the body into head, viscera and trunk revealed that 45–48% of the body lipids were stored in the trunk, independent of diet composition. A positive relation between dietary and body protein level was confirmed in this experiment. However, the dissection of the body revealed that the body protein concentrations in head + viscera and trunk are not changed significantly by the dietary protein level. The higher protein contents offish fed higher-protein diets are due to an increase in the relative weight of the trunk (muscle) to the total body weight.  相似文献   

17.
A feeding trial was conducted to investigate the effects of dietary graded protein levels on the growth, survival, amylase and trypsin activities of large yellow croaker (Pseudosciaena crocea R.) larvae from 12 to 42 days after hatching (DAH). Five approximately isoenergetic microbound diets (16.65 MJ/kg diet) were formulated to contain different protein (47.1%, 52.0%, 57.1%, 62.2% and 67.5%) levels. Frozen copepods, containing 54.5% crude protein (CP), 6.0% crude lipid, 27.2% ash and 6.7% glycogen, were used as a control. Each diet was randomly fed to triplicate groups of larvae with an initial mean body weight of 1.76 ± 0.09 mg (mean ± SD) in 180 L white plastic tanks, and each tank was stocked initially with 3500 larvae. Both the survival and the specific growth rate (SGR) of large yellow croaker larvae significantly increased with increasing dietary protein level up to 57.1%, and decreased thereafter. Frozen copepods resulted in intermediate survival and low SGR compared with the other diets. Whole‐body moisture and protein of larvae were not significantly affected by the dietary protein level. In contrast, whole‐body lipid of larvae fed diet with 47.1% CP was significantly higher (P<0.05) than those from fish fed the diets containing more than 57.1% CP. Additionally, fish fed the frozen copepods had the lowest whole‐body protein and lipid. The amylase‐specific activity increased with increasing dietary carbohydrate level during the period of this experiment. However, trypsin activity was not significantly affected by the dietary protein content before 42 DAH, indicating a later onset of trypsin than amylase in the regulation of enzymatic synthesis induced by a dietary substrate.  相似文献   

18.
A nutrition trial was conducted to investigate the effects of dietary lipid levels and supplemental Ulva meal on growth performance, feed efficiency, nutrient utilization, and body composition of juvenile Nile tilapia, Oreochromis niloticus. Four isonitrogenous (CP 40%) diets containing 0% and 5% Ulva meal were formulated to contain 10% (low-lipid; LL) and 20% (high-lipid; HL) crude lipid. Triplicate groups of fish (~10 g) were fed to apparent satiation three times daily for 16 weeks. Fish fed 5% Ulva meal showed an increased growth performance (P < 0.05) compared with fish fed non-Ulva supplemented diets, irrespective of dietary lipid level. In particular, the incorporation of Ulva meal improved specific growth rate (SGR), feed conversion ratio (FCR), and protein efficiency ratio (PER). Feeding fish 5% Ulva meal diets resulted in significantly lower carcass lipid content. The results indicate that 5% inclusion of Ulva meal at both dietary lipid levels improves growth performance, feed efficiency, nutrient utilization, and body composition of Nile tilapia.  相似文献   

19.
Raw corn starch (RCS), raw tapioca starch (RTS), raw potato starch (RPS), pre‐gelatinized corn starch (PCS), pre‐gelatinized tapioca starch (PTS) and pre‐gelatinized potato starch (PPS) were evaluated as starch sources in diets for yellowfin seabream Sparus latus in a 56‐day growth trial. Seven isonitrogenous semi‐purified diets comprising a non‐starch cellulose control diet and the six different starch sources holding 200 g kg−1 starch each were prepared and fed to triplicate groups of juvenile yellowfin seabream S. latus. Fish were fed for 8 weeks. Weight gain (WG) and specific growth rate (SGR) for fish fed RCS, RTS and RPS diets were equal, as well as for fish fed PCS, PTS and PPS diets, but values in groups fed the raw starch sources were significantly higher compared with fish fed the pre‐gelatinized starches. Feed efficiency and protein efficiency ratio in fish fed different starch source diets showed no significant differences but were significantly higher than those fed a non‐starch control diet. Protein productive value was improved by starch incorporation to diets. PCS, PTS or PPS groups showed lower feed intake compared with RCS, RTS or RPS groups, and the differences were significant between PCS, PPS and RCS, RPS groups. Whole‐body protein and ash contents and muscle compositions were not affected by different starch sources. Whole‐body and liver lipid contents, liver moisture and glycogen contents were significantly affected by starch source. Values of hepatosomatic index, intraperitoneal fat ratio, viscerosomatic index and condition factor did not vary between experimental treatments. Plasma total protein concentration for RCS, RTS or RPS fed fish was significantly higher than that for PCS, PTS or PPS fed fish, but significantly lower than that for non‐starch fed fish. Plasma cholesterol and triacylglycerol concentrations were unaffected by starch source, but were significantly higher in fish fed the non‐starch control diets. Plasma glucose concentrations in all dietary groups were relatively stable. In conclusion, raw corn, tapioca and potato starches at a 200 g kg−1 inclusion level were well utilized as energy sources by yellowfin seabream, which was evidenced by better WG and SGR. Pre‐gelatinization of the starches had no positive effect on starch utilization.  相似文献   

20.
A study was conducted at Bunda Fish Farm to evaluate the effects of dietary lipid levels on reproductive performance of Oreochromis karongae. Fish were reared in 12 hapas for 86 days, with four experimental diets containing 8.28%, 10.17%, 12.09% and 14.05% levels of lipid, replicated three times. At the end of the experiment, O. karongae fed 10.17% and 12.09% lipid had the highest absolute fecundity (237.5 ± 6.50 and 271.3 ± 26.19, respectively) as compared with fish fed on 8.28% and 14.05% lipid levels (90.3 ± 46.3 and 143.7 ± 30.8 respectively). Higher number of spawns (5) were observed in fish fed on diets containing crude lipid of 10.17%. We can assume also that diets of 10.17% lipid are not costly as those of 12.09% or 14.05% lipid. It was found that the size of eggs depended on the number of eggs spawned by the female fish, as the number of eggs increased, the weight of eggs and mean egg diameter decreased. There were no significant differences (P > 0.05) among treatments in terms of relative fecundity. Based on these findings, it is recommended that diets containing crude lipid of 10% should be fed to broodstock for optimum reproductive performance of O. karongae.  相似文献   

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