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1.
The effect of microbial phytase on phosphorus utilization in juvenile Clarias gariepinus (initial fish body weight 11.55 ± 0.2 g) was tested on two different diets based on oil-extracted soya bean (Experiment 1) and roasted soya bean meal (Experiment 2) using a 5 × 5 experimental design for 84 days. The basal isonitrogenous and isocaloric diets for oil-extracted and roasted soya bean were formulated to replace fish meal at 25% (S1E), 50% (S2E), 75% (S3E), 100% (S4E); and 25% (S1), 50% (S2), 75% (S3), 100% (S4), respectively. Each treatment was replicated four times. Microbial phytase was supplemented in each replicate at 250 FTU/g (P1), 500 FTU/g (P2), 750 FTU/g (P3), and 1,000 FTU/g (P4). Basal controls, which included a fish meal-based diet (S0), were not supplemented with phytase (P0). The result in Experiment 1 showed that there was a significant increase in whole-body protein and reduction in fat with phytase compared to a diet without phytase (P < 0.05). Serum total protein declined significantly with phytase supplementation (P < 0.05). Serum phosphorus and glucose were higher with phytase supplementation compared to control (P < 0.05). Bone minerals declined significantly with increasing level of soya bean compared to fish meal diet (P < 0.05). In Experiment 2, serum phosphorus was improved with phytase compared to control with no phytase (P > 0.05). A significant reduction in whole-body protein and increase in fat was observed for fish fed phytase diets compared to diets with no phytase, regardless of soya bean level (P < 0.05); however, ash content was improved with phytase (250 FTU/g) compared to control (P < 0.05). Phytase supplementation improved bone phosphorus (250 FTU/g), calcium (250 FTU/g), magnesium (250–500 FTU/g), and zinc (250–1,000 FTU/g) compared to control (P < 0.05). In conclusion, the research has demonstrated that improved bone phosphorus (P) and growth could be achieved with the supplementation of dietary phytase.  相似文献   

2.
A feeding trial was conducted to quantify the effects of phytase at levels of 0, 500, 1,000, 2,000, 4,000, and 8,000 units (U) per kg diet on utilization of dietary protein and minerals by fingerling (12 g) channel catfish Ictalurus punctatus fed an all‐plant‐protein diet composed of soybean meal, corn, and wheat middlings. The effects of phytase on dephosphorylation of phytic acid (phytate) in the alimentary tract of catfish also were determined. After 14 wk, mean weight gains (30.2–43.9 g/fish), feed conversion ratios (2.27–2.40 g feed consumed/g weight gain), protein efficiency ratios (1.47–1.61 g weight gaid/g protein consumed), and dietary protein retentions (23.8–26.7%) did not differ significantly (P > 0.05) among treatment groups. A digestibility trial conducted after the feeding trial showed no difference (P > 0.05) in mean digestibility of diet dry matter (49.0–58.3%) or crude protein (85.4‐88.5%) among treatment groups. Concentrations of ash (46.7–48.6%), calcium (Ca, 17.9–18.5%), phosphorus (P, 9.1–9.5%), and manganese (Mn, 65.5–74.1 mg/kg) were significantly higher (P ≤ 0.05) in bone of fish fed ≥ 500 U/kg than in bone of fish fed 0 U/kg (ash, 43.5%; Ca, 16.4%; P, 8.4%; and Mn, 49.0 ma/kg), but concentrations of these minerals did not differ (P > 0.05) in bone of fish fed ≥ 500 Uk/g. The magnesium (Mg) content of bone did not differ (P > 0.05) between fish fed 0 U/kg (0.29%) or 500 U/kg (0.34%), but was significantly lower in fish fed 0 U/kg than in fish fed ≥ 1,000 U/kg (0.35–37%). Bone Mg levels did not differ (P > 0.05) among fish fed ≥ 500 U/kg. The amount of zinc (Zn) in bone of fish fed 8,000 U/kg (153.3 mg/kg) was significantly higher than that in fish fed 0 U/kg (115.7 mg/kg) or 500 U/kg (130.3 mg/ kg), but did not differ from Zn levels in bone of fish fed 1,000–4,000 U/kg (134.5–135.8 mg/ kg). Dephosphorylation of phytate occurred primarily in the stomach within 2–8 h after diet ingestion, depending on the level of phytase supplementation. Initial levels of total phytate in the diet decreased 32–94% in stomach contents of fish fed l,000–8,000 U/kg within 2 h after feeding. Eight hours after feeding, stomach contents of fish fed ≥ 1,000 U/kg contained less than 6% of initial total dietary phytate. Stomach contents of fish fed 500 U/kg retained 92% of initial total dietary phytate 2 h after feeding and 15% of total dietary phytate 8 h after feeding. Results of this study indicate that phytase supplementation at levels up to 8,000 U/kg diet did not increase weight gain or improve dietary protein utilization of channel catfish fed an all‐plant‐protein diet. Addition of phytase at a level of 1,000 U/kg diet was sufficient to significantly increase the Ca, P, Mg, and Mn content of bone, relative to fish fed an unsupplemented diet, and significantly decrease the quantity of total phytate in feces. A phytase level of 8,000 U/kg diet significantly increased the bioavailability of naturally occurring Zn in feed ingredients and increased the rate of phytate dephosphorylation in the stomach, compared with a diet containing no added phytase. Increased utilization of naturally occurring minerals in feed ingredients reduces the need for mineral supplements in diets and results in decreased elimination of minerals in feces. Thus, use of phytase in catfish feeds can be expected to provide both economic and environmental benefits.  相似文献   

3.
Effects of dietary phytase, amino acid (AA), and inorganic phosphorus (P) in soybean meal (SBM) diets on the growth, feed utilization, and P waste of Australian catfish, Tandanus tandanus, were evaluated. In Experiment 1, SBM replaced 30% of fishmeal (FM) protein in the four test diets, supplemented with phytase (1000–3000 FTU/kg). In Experiment 2, SBM replaced 45% of FM protein in the four test diets, supplemented with phytase, AAs, inorganic P, or their combinations. Inclusion of 3000 FTU/kg significantly improved growth performance and feed utilization of catfish. Ortho‐P waste was significantly lower in fish fed with SBM diets. At 30% FM protein replacement, dietary SBM did not reduce the total P waste of catfish while dietary phytase significantly did. At 45% FM protein replacement, phytase alone did not significantly improve the growth and feed utilization of catfish fed with SBM diets while significantly better results were obtained when both phytase and AAs were supplemented. Dietary inclusion of inorganic P significantly decreased P utilization and increased P waste of the fish. Dietary phytase significantly improved P utilization of catfish in both experiments.  相似文献   

4.
The study was carried out with juvenile European catfish to evaluate the effects of commercial diets on growth, feed utilization and changes of selected morphometric traits of fish. Three diets containing different levels of crude protein and lipid: 37 and 12 %, 45 and 15 %, 45 and 20 %, respectively, were fed to triplicate groups of European catfish for 50 days. The fish were fed continuously (24 h day?1) by automatic belt feeders for fish with a clock drive. Biometric characteristics of fish included the determination of plasticity traits using modified Pravdin method. Fish growth rate and final body weight were statistically higher in variant 45/20 diet (specific growth rate of 2.6 % day?1). The intergroup significant differences were recorded for food conversion ratio (FCR) and protein efficiency ratio (PER), during the particular decades of the experiment. For the whole period of the growth test, no significant differences in FCR were observed, but the most favorable values of PER were obtained in variant 37/12. Protein retention in fish body ranged from 18.7 to 21.0 %, and fat retention was significantly more variable, ranged from 87.5 to 121.3 %. Fish survival rate recorded during the growth test was higher in all variants (above 95 %). Statistically significant increases in protein and lipid content were found in fish fed diets 45/15 and 45/20. The tested diets have no effect on changes in fish body proportions. The most effective in juvenile European catfish rearing was diet with 45 % of crude protein and 20 % of lipid.  相似文献   

5.
Abstract

Two experiments were conducted to evaluate the effects of microbial phytase in corn distiller's dried grain with solubles (DDGS) on apparent digestibility coefficients (ADCs) and growth performance of rainbow trout, Oncorhynchus mykiss. In experiment 1, DDGS was supplemented with phytase at 0,300,600,900, and 1200 FTU/kg diet. A total of 180 fish (129.1±9.3 g) were stocked into six 140-L tanks with 30 fish/tank. Fish were assigned randomly to a reference diet and each of the 5 diets containing DDGS. Yttrium oxide was used as an inert marker. Results showed that ADCs in DDGS supplemented with different dosages of phytase were: dry matter, 49.1-58.6%; crude fat, 78.9-88.9%; crude protein, 80.0-91.9%; gross energy, 50.5-66.6%; minerals, -7.3-99.7%; and amino acids: 73.9 to 96.8%. In experiment 2, abasal diet containing 15% DDGS supplemented with lysine and methionine was used to determine if trace mineral supplemental levels in rainbow trout diets could be reduced if microbial phytase was supplemented. Six diets were made with trace mineral premix supplementation at 0.1, 0.08, 0.06, 0.04, 0.02, and 0%. Phytase was not supplemented in the basal diet, but supplemented at 500 FTU/kg diet in all other diets. Ten-week results showed that there were no significant differences in fish weight gain, feed conversion ratio, and survival (P < 0.05). There were no significant differences in fish body composition and apparent nutrient retention among fish fed all diets, except that fish fed a diet without trace mineral supplementation had the lowest zinc level and the highest manganese retention. Results indicated that phytase was effective in releasing most of minerals, and that trace mineral supplementation level could be reduced when phytase was used in rainbow trout diets.  相似文献   

6.
Abstract.– Juvenile channel catfish Ictalurus punctatus (initial weight: 6.8 g/fish) were fed four practical diets containing 0, 250, 500, and 750 units of microbial phytase/kg and a diet containing 1% feed grade dicalcium phosphate (but no microbial phytase) under laboratory conditions for 12 wk. Fish fed the diets containing 250 units of microbial phytase/kg and above consumed more feed, gained more weight, and had a lower feed conversion ratio (FCR) in comparison to fish fed the basal diet containing no microbial phytase. Fish fed the diet containing dicalcium phosphate had intermediate weight gain and feed conversion ratio as compared to fish fed the basal diet and diets containing microbial phytase. Bone ash and phosphorus concentrations were lower for fish fed the basal diet than for fish fed other diets. No differences in weight gain, feed consumption, FCR, bone ash and bone phosphorus were observed among fish fed the diets containing various levels of microbial phytase. Fish fed the diet containing dicalcium phosphate had a lower bone phosphorus concentration than fish fed diets containing microbial phytase. Fecal phosphorus concentrations were lower for fish fed the diets containing microbial phytase than for fish fed the basal diet and the diet containing dicalcium phosphate. Results from the present study indicated that addition of 250 units of microbial phytase/kg to practical diets can effectively improve bioavailability of phytate phosphorus to channel catfish and may possibly eliminate the use of an inorganic phosphorus supplement in channel catfish diets. However, these data must be verified in trials conducted in ponds, prior to recommending removal of supplemental phosphorus from channel catfish diets.  相似文献   

7.
Six isonitrogenous (320 g kg?1) and isolipidic (60 g kg?1) diets were formulated with graded levels (0, 5, 10 and 15 g kg?1) of dicalcium phosphate (DCP) and fungal phytase (750 and 1500 FTU kg?1 diet). Tra catfish (Pangasianodon hypophthalmus), 9.6 g, were fed the diets for 12 weeks. Each experimental diet was fed to eight replicates of fish to apparent satiation. At the end of the trial, fish fed the diets containing 15 g kg?1 DCP, 750 and 1500 FTU kg?1 phytase had higher growth performances, protein efficiency ratio and phosphorus retention than those fed the control diet, 5 g kg?1 DCP and 10 g kg?1 DCP diets (P < 0.05). Whole body ash and phosphorus concentration of fish fed the 10 g kg?1 DCP and 15 g kg?1 DCP diets were significantly higher than those of fish fed the control diet. Higher apparent digestibility coefficient of phosphorus was observed in fish fed the phytase supplemented diets. The present results indicate that supplementation of phytase at 750 FTU kg?1 and 1500 FTU kg?1 improves growth performances, feed and phosphorus utilization. The supplementation can completely replace dicalcium phosphate or other phosphorus sources in tra catfish feed and reduce the phosphorus discharge into environment.  相似文献   

8.
A 10-wk feeding trial was conducted in the laboratory during which channel catfish Ictalurus punctatus (average initial weight: 6.5 g/fish) were fed five practical diets containing either 0, 500, 1,000, 2,000, or 4,000 units of microbial phytase/kg diet. Fish fed diets containing 500 or more units of microbial phytase/kg consumed more feed and gained more weight than fish fed the basal diet without supplemental phytase. Feed conversion ratios (FCR) did not differ among treatments except the FCR for fish fed 1,000 units of microbial phytase/kg diet was lower than that of fish fed no supplemental phytase. Fish survival was not different among treatments. Contrast analysis showed that weight gain, feed consumption, bone ash, and bone phosphorus were higher and feed conversion ratio was lower for fish fed diets supplemented with phytase as compared to fish fed no supplemental phytase. The concentration of fecal phosphorus decreased linearly as phytase supplementation increased. Results from this study demonstrate that microbial phytase is effective in improving bioavailability of phytate phosphorus to channel catfish, which may eventually lead to a reduction in the amount of supplemental phosphorus added to commercial channel catfish feeds.  相似文献   

9.
Three experiments were conducted to evaluate the effects of microbial phytase (Ronozyme P(L) and dosage on apparent digestibility coefficients of dry matter, crude protein, amino acids, and minerals in soybean product-based diets for rainbow trout Oncorhynchus mykiss. In experiments 1 and 2, fish were fed soy protein concentrate and soybean meal-based semi-purified diets, respectively. In experiment 3, fish were fed soybean meal-based practical diets. A total of 900 fish (average body weight 100.1 ± 7.4 g) were stocked into 30 150-L fiberglass tanks with 30 fish per tank and two tanks per diet. Phytase was supplemented into soybean product-based diets at 0, 500, 1,000, 2,000, and 4,000 FTU/kg diet. Yttrium oxide (0.01%) was used as inert marker. Feces were collected by hand stripping three times at 3-d intervals. Results of experiments 1 and 2 showed that phytase supplementation significantly increased apparent digestibility coefficients of minerals (except copper and iron), but not dry matter. Experiment 3 showed that phytase supplementation significantly increased apparent digestibility coefficients of dry matter, crude protein, amino acids (except tryptophan and tyrosine), and minerals (except copper and iron). The optimum level of phytase supplementation in rainbow trout diets was approximately 500 FTU/kg diet.  相似文献   

10.
The value of toasted Mucuna utilis seed meals was investigated in this study by evaluating the nutritional profile and the utilization of the processed seeds in isonitrogenous (35% CP) and isocaloric diets (17 kJ g?1) for African catfish Clarias gariepinus (Burchell 1822). Toasting the M. utilis seed significantly reduced the levels of tannins, phytate, trypsin, and hemagglutinin in the seeds. However, protein, gross energy, arginine, histidine, and valine were increased (P ≤ 0.05). The processed seed was then used to formulate five experimental diets by progressively increasing its inclusion (by 50 g kg?1) from zero up to 200 g kg?1. A sixth diet was also formulated with raw M. utilis included at 200 g kg?1 to determine the efficacy of the processing method applied in this study. Fifty fingerlings of C. gariepinus (2.02 g ± 0.08) stocked in 18 hapas measuring 1 × 1 × 1 m3 were then fed the diets for 56 days. The growth of C. gariepinus fingerlings was significantly improved by the addition of the toasted M. utilis seed meal. However, fish fed the diet containing 200 g kg?1 of raw M. utilis had poor growth with higher mortality (35%). Estimation of the feeding cost using the diets revealed reduction in production cost of fish with the inclusion of toasted M. utilis seed meal. It was concluded that toasting significantly improved the nutritional quality of this unconventional feedstuff, allowing better utilization at up to 200 g kg?1 inclusion level in the diet of African catfish C. gariepinus.  相似文献   

11.
A 2 × 3 factorial feeding trial was conducted to determine effects of dietary Ca/P ratio and dietary microbial phytase on growth, mineral digestibility and vertebral mineralization in tiger puffer. The treatments consisted of three levels of Ca/P ratios (0.5, 1.0 and 1.5) combined either with phytase (2000 FTU kg?1 diet) or without supplementation, respectively. The Ca/P ratios were achieved by supplementing calcium at 0, 6 and 12 g kg?1 combined with the same level of inorganic P at 5 g kg?1. After a 50‐day feeding trial, puffer fish fed the diet at low Ca/P ratio (0.5) together with phytase had significantly higher growth rate and feed intake (FI) than other groups. Both dietary Ca/P ratio and phytase supplement were independent effects on plasma minerals and alkaline phosphatase. Interactive effect between both dietary treatments was observed on P and Zn contents in vertebrae and whole body. P and Zn digestibilities tended to increase with increased Ca/P ratio from 0.5 to 1.0, especially when phytase was supplemented. In conclusion, fish fed a diet with highest Ca/P ratio (1.5) showed the poorest growth performance and nutrients utilization. Dietary Ca/P ratio of 0.5 (without Ca supplement) with 2000 FTU phytase per kg would be the optimum combination in the diet of tiger puffer.  相似文献   

12.
A 2 × 3 factorial design with triplicates examined the interaction between dietary inorganic phosphorus (IP) and phytase on growth, mineral utilization and phosphorus (P) mineralization in juvenile red sea bream. The treatments were three levels of dietary IP supplementation at 0, 2.5 and 5 g kg?1, either without or with phytase supplementation [2000 FTU kg?1; phytase unit is defined as the amount of enzyme activity which liberates 1 micromol of inorganic phosphorus per minute at pH 5.5 and 37 °C at a substrate concentration (sodium phytate) of 5.1 mmol L?1]. Juvenile red sea bream (IBW = 1.3 g ± 0.1) were stocked twelve fish per tank and fed for 50 days. Growth and feed efficiency were significantly (P < 0.05) enhanced by both dietary P and phytase supplementation. Feed intake and survival rate were not significantly affected by the dietary treatments. Both dietary IP and phytase supplementation significantly increased plasma IP and Mg levels. Concentration of vertebral mineral and scale P was significantly increased by both dietary treatments. A skeletal malformation syndrome of scoliosis occurred in fish fed both non‐IP and non‐phytase supplemented diet. Interaction between main dietary effects was detected for vertebral Zn, scale P and whole‐body ash and Mg content. With regard to growth and other examined productivity traits, phosphorus requirement of juvenile red sea bream can be met if supplemented with 2000 FTU phytase kg?1 or in the absence of phytase, by dietary inclusion of 2.5–5 g kg?1 of IP.  相似文献   

13.
Growth, feed conversion, and nutrient retention efficiencies of African catfish fingerling, Clarias gariepinus (5.22 ± .07 cm; 8.22 ± 0.03 g), fed diets with varying levels of protein were assessed by feeding seven casein/gelatin based isocaloric (17.62 kJ/g GE) experimental diets with graded levels of dietary protein (20%, 25%, 30%, 35%, 40%, 45%, and 50% of the diet) to triplicate groups of fish to apparent satiation for eight weeks. Effects of feeding these diets on live weight gain (LWG%), feed conversion ratio (FCR), protein efficiency ratio (PER), protein retention efficiency (PRE%), and energy retention efficiency (ERE%) were assessed. Maximum LWG% (867%), PER (2.01), highest PRE (32%), ERE (69%), best FCR (1.39), and maximum body protein were recorded in fish fed diet containing 35% protein. On the basis of the second-degree polynomial regression analysis of the above response variables, it is recommended that the inclusion of protein in the range of 34.4%–39.6% is optimum for maximizing growth potential, feed conversion, and nutrient retention in African catfish fingerling, Clarias gariepinus.  相似文献   

14.
This study evaluated the effect and phosphorus equivalency value of dietary microbial phytase based on growth performance and nutrient utilization of Channel catfish (Ictalurus punctatus). An all plant‐protein basal diet containing 7.9 g/kg total Phosphorus (P) (Phytate P of 4.5 g/kg) was supplemented with graded levels 0, 300, 500, 1,000, 1,500 and 2,000 U phytase/kg of diet or with 3, 5, 8, 12 g/kg of Ca(H2PO4)2, namely with 0.7, 1.2, 2.0, 3.09 g/kg P as Ca(H2PO4)2. Triplicate groups of Channel catfish (Ictalurus punctatus) juveniles (initial weight, 1.70 ± 0.04 g) were fed the experiment diets for 90 days. The results indicated that dietary phytase supplementation significantly improved growth performance, apparent digestibility coefficient of P and P retention, and decreased feed conversion ratio (FCR), faecal P content and P excretion per gain. Line relation was found between the effects of P and phytase supplementation levels, and the linear response equations of the effects of P and phytase levels were generated and used to calculate the P equivalency values. The average function of P equivalency values (Y, g/kg) of microbial phytase (X, U/kg of diet) was developed: Y = 0.1695 + 0.0021X; R2 = 0.996. The results showed that about 0.38 g of P/kg diet was released by per 100 U of phytase over the range of 300–2,000 U of phytase/kg diet for Channel catfish (Ictalurus punctatus) fed all plant‐protein diet.  相似文献   

15.
Balance trials were conducted with African catfish Clarias gariepinus to assess the effect of phytase treatment of soybean meal-based diets on growth, feed utilization and nutrient budgets. Isocaloric (20–22 kJ g−1) and isonitrogenous (47–50% protein) diets were tested. In a first experiment the control diet (58% fish meal and 18% soybean meal) was compared with two diets containing 6% fish meal and 69% soybean meal, and two diets containing 29% fish meal and 41% soybean meal. One of each of these two diets had been pretreated with phytase (1000 units per kg dry diet). In the second experiment, the control diet (6% fish meal and 69% soybean meal, pretreated with 1000 units phytase kg−1 dry diet) was compared with four diets that were similar in composition but supplemented with increasing amounts of phytase (15, 380, 750, 1000 units kg−1 dry diet). Replacement of fish meal by soybean meal in the first experiment led to a depression in growth rate and feed utilization parameters. Results of both experiments clearly indicated a positive effect of phytase treatment, particularly on phosphorus digestibility and retention, and consequently the phosphorus conversion efficiency and the phosphorus budget. No differences in these parameters were found between addition of equal amounts of phytase by pretreatment or supplementation.  相似文献   

16.
This study was conducted to investigate the growth performance, biomarkers of oxidative stress, catalase (CAT), superoxide dismutase (SOD), and glutathione S-transferase (GST) as well as the haematological response of African catfish after being fed with fish feed containing different levels of cricket meal. The juvenile fish were assigned to three different treatments with isonitrogenous (35 %) and isoenergetic (19 kJ g?1) diets containing 100 % cricket meal (100 % CM), 75 % cricket meal (75 % CM), and 100 % fishmeal (100 % FM) as control groups for 7 weeks. The results indicated that a diet containing 100 % CM and 75 % CM improved growth performance in terms of body weight gain and specific growth rate, when compared to 100 % FM. The feed conversion ratio (FCR) and protein efficiency ratio (PER) did not differ significantly between all diets, but reduced FCR and increased PER were observed with a higher inclusion of cricket meal. A haematological examination of fish demonstrated no significant difference of red blood cells in all diets and white blood cells showed a significantly higher value in fishmeal-fed fish. On the other hand, haemoglobin and haematocrit significantly increased with increasing amounts of cricket meal in the diet. Antioxidant activity of CAT was higher in the 100 % CM group compared to fish fed other diets, whereas GST and SOD showed increasing trends with a higher incorporation of cricket, although insignificant differences were observed between all diets. These results suggest that cricket meal could be an alternative to fishmeal as a protein source in the African catfish diet.  相似文献   

17.
This study was conducted to evaluate the potential of graded levels of GroBiotic®‐A to improve performance of Nile tilapia, Oreochromis niloticus, fed a 29% crude protein (CP) diet. A 29% CP diet was formulated and supplemented with 0, 0.4, 0.8, and 1.2% GroBiotic®‐A and compared to performance of fish fed a 33% CP diet. Enhanced weight gain and feed efficiency were generally observed in fish fed the diets supplemented with GroBiotic®‐A compared to the 29% CP diet. No significant differences in these responses were observed between fish fed diets supplemented with GroBiotic®‐A compared to those fed the 33% CP diet. Supplementation of 0.8 and 1.2% GroBiotic®‐A induced significantly lower condition factor and hepatosomatic index compared to fish fed the 29% CP diet, but those values were similar to that of fish fed the 33% CP diet. GroBiotic®‐A supplementation and protein reduction had no effect on the viscerosomatic index of fish or moisture, lipid, and protein content of muscle samples. However, muscle ash increased significantly with protein reduction (29% CP diet), but GroBiotic®‐A supplementation (0.8 and 1.2%) reduced muscle ash content. Activities of catalase and superoxide dismutase were markedly reduced in fish fed GroBiotic®‐A (0.8 and 1.2%) compared to those fed the control diet. GroBiotic®‐A supplementation also induced significantly higher neutrophil oxidative radical production compared to fish fed the 29% CP diet, but no significant difference was observed in comparison with the 33% CP diet. After 8 wk of feeding, exposure to Aeromonas hydrophila for 3 wk resulted in 40% (0.4, 0.8% GroBiotic®‐A) and 27% (1.2% GroBiotic®‐A) mortality and reduced signs of disease, while 47% mortality was observed in fish fed the 29% CP diet. Based on the result of this study, it is concluded that 0.8 and 1.2% GroBiotic®‐A positively influenced growth performance and feed efficiency of tilapia fed diets containing 29% crude protein to levels comparable to fish fed the 33% CP diet. GroBiotic®‐A supplementation also significantly increased neutrophil oxidative radical production as well as resistance to Ae. hydrophila infection.  相似文献   

18.
This study was conducted to find the optimum level of dietary protein and lipid that could produce the highest growth, best feed utilization, and body composition of African catfish, Clarias gariepinus (9.5–10.3 g). Nine diets (three protein levels × three lipid levels) containing 25, 30, or 35% crude protein (CP) with 6, 9, and 12% lipids were formulated. Fish were fed one of the tested diets at the rate of 5% of body weight for the first 8 wk and 3% for the rest of the study. Diets were offered 6 d a week, twice a day (900 and 1400 h) for 13 wk. Fish growth increased significantly with increasing either protein or lipid levels, and the maximum growth was obtained in fish fed diets containing 30% CP with 12% lipid or 35% CP with 9% lipid. The lowest fish growth was obtained at 25% CP with 6% lipid. The optimum feed intake, feed conversion ratio, energy utilization, protein efficiency ratio, and protein growth rate were also recognized in fish fed the above diets. No significant differences in moisture and ash contents in fish fed diets containing different protein and lipid levels were recorded. The protein and lipid contents in the fish body tended to increase with increasing protein and lipid levels in diets. However, the higher protein contents were obtained in fish fed diets containing 35% CP with 6 or 9% lipid, while the lowest ones were obtained at 25% CP with 6 or 9% lipid. The higher lipid contents were obtained at 30 or 35% CP with 12% lipid, while the lowest ones were obtained at 25 or 35% CP with 6% lipid. The present study indicates that the increase of dietary lipid level has a protein-sparing effect, and the diet containing 30% CP with 12% lipid would be suitable for the optimum growth and effective protein utilization of fingerling African catfish.  相似文献   

19.
This study was performed to determine the dietary methionine requirements and its effects on growth performance, plasma and hepatic metabolites for juvenile silver catfish. The fish (initial weight = 3.26 ± 0.3 g) were distributed in 24 experimental units (35 fish each). Six diets were formulated with increasing levels of methionine (09, 16, 23, 30, 37 and 44 g/kg protein diet). Each diet was distributed randomly to the groups, with four replicates fed twice daily to apparent satiation for 15 weeks. Methionine levels influenced in body composition (moisture and ash), and submit effect on liver metabolism and plasma. The relative weight gain (RWG) and specific growth rate (SGR) increased with highest levels of methionine to 30 g/kg protein in the diet, thereafter maintaining a nearly constant level of 1.9 g/kg cystine in the protein diet. The protein retention coefficient (PRC) also increased with increasing levels of up to 23 g/kg protein diet, thereafter maintaining a constant level of 1.9 g/kg cystine protein diet until beginning to decrease at a level of 44 g/kg protein diet. In conclusion, methionine is an essential amino acid for the growth of juvenile silver catfish and exhibits an efficient capacity when provided as a synthetic amino acid. Based on the RWG and SGR data, the methionine requirement of juvenile silver catfish was estimated at 34.42 and 35.85 g/kg of the CP or 12.74 g/kg and 13.26 g/kg of the diet respectively.  相似文献   

20.
An 8‐week feeding trial was conducted in flow through system to examine the effects of dietary supplementation of microbial phytase on growth, nutrient utilization, haemato‐biochemical status and body compositions in common carp, Cyprinus carpio (L.) fingerlings (average weight 6.66 ± 0.08 g). The aim of experiment was also to determine whether dicalcium phosphates (DCP), tracemineral premix and lysine and methionine supplemental levels in carp diet could be reduced if microbial phytase was supplemented. Control diet (diet 1) supplemented with DCP, tracemineral premix and lysine and methionine without microbial phytase supplementation. Four experimental diets were formulated with reduction of either dietary DCP or trace minerals or lysine and methionine or all four supplementation levels by 100% of control diet without microbial phytase supplementation (diet 2, 3, 4 and 5 respectively). Another two experimental diets were formulated with reduction of all dietary DCP, trace minerals, lysine and methionine supplementation levels by 0 and 100% of control diet with dietary microbial phytase supplementation at 500 FTU kg−1 diet (diet 6 and 7 respectively). After acclimation of fish for 2 weeks, 20 fish were randomly stocked into triplicate tanks for each of seven treatments (T0, T1, T2, T3, T4, T5 and T6 for diet 1, 2, 3, 4, 5, 6 and 7 respectively) and fed with respective diet to apparent satiation. Results indicated that phytase was effective in releasing most of the phytate bound proteins, amino acids and minerals for optimum utilization and performance. Results also suggested that DCP, trace minerals and lysine and methionine supplementation level could be replaced by microbial phytase supplementation at 500 FTU kg−1 in soybean‐based common carp diets without altering the optimum performance of fish. Optimum replacement level of dietary DCP, trace minerals and lysine and methionine with phytase supplementation at 500 FTU kg−1 soybean‐based carp diet needs to be standardized in further investigations.  相似文献   

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