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1.
A growth trial was conducted to estimate the optimum requirement of dietary zinc (Zn) for grass carp (Ctenopharyngodon idella). Triplicate groups of grass carp (3.97 ± 0.05 g) were fed diets containing graded levels (13, 25, 34, 53, 89 and 135 mg kg?1) of Zn for 8 weeks. Grass carp fed with dietary Zn levels higher than 34 mg kg?1 significantly increased final body weight, weight gain and specific growth rate (P < 0.05). For body composition, fish fed with dietary Zn levels higher than 53 mg kg?1 significantly decreased the moisture contents but increased the lipid contents of whole body and liver. Whole body, scales, vertebrae and liver mineralization were all affected significantly (P < 0.05) by dietary Zn levels. Zn contents in whole body, scales, vertebrae and plasma were linearly increased up to the 53 mg kg?1 dietary Zn and then remained stable beyond this level. Grass carp fed with dietary Zn levels higher than 53 mg kg?1 significantly increased triacyglyceride and total cholesterol contents and plasma alkaline phosphatase activity in plasma (P < 0.05). Broken‐line analysis indicated that 55.1 mg kg?1 dietary Zn was required for maximal tissue storage and mineralization as well as optimal growth of grass carp.  相似文献   

2.
A growth trial was conducted to estimate the optimum concentration of dietary magnesium (Mg) for grass carp (Ctenopharyngodon idella). Triplicate groups of grass carp (5.56 ± 0.02 g) were fed diets containing graded levels (187, 331, 473, 637, 779 and 937 mg kg?1) of Mg for 8 weeks. Weight gain, specific growth rate and feed efficiency were linearly increased up to 637 mg kg?1 dietary Mg and then levelled off beyond this level. For body composition, dietary Mg levels higher than 473 mg kg?1 significantly decreased the moisture content but increased the lipid content of whole body, muscle and liver. Dietary Mg levels higher than 473 mg kg?1 significantly decreased the ash contents of vertebrae, scales and muscle. Mg contents in whole body, vertebrae, scales and plasma were increased up to 637 mg kg?1 dietary Mg and then levelled off beyond this level. However, Ca and P contents seem to be inversely related to dietary Mg. Dietary Mg levels higher than 473 mg kg?1 significantly decreased Zn and Fe contents in whole body and vertebrae. Broken‐line analysis indicated that 687 mg kg?1 dietary Mg was required for maximal tissue Mg storage, as well as satisfied for the optimal growth.  相似文献   

3.
A growth trial was conducted to estimate the optimum concentration of dietary potassium (K) for grass carp (Ctenopharyngodon idella). Triplicate groups of grass carp (3.96 ± 0.06 g) were fed diets containing graded levels (0.87, 2.90, 5.37, 7.54, 9.87 and 12.4 g kg?1) of K for 8 weeks. Final body weight, weight gain and feed efficiency and gill Na+‐K+ ATPase activity were highest in fish fed with 9.87 g kg?1 dietary K and lowest in fish fed the basal diet (P < 0.05). The K contents in whole body and muscle were linearly increased up to the 9.87 g kg?1 dietary K and then levelled off beyond this level, whereas in scales and vertebrae up to the 7.54 g kg?1 dietary K (P < 0.05). However, dietary K levels had no significant effect on ash, Ca, P and Mg contents in whole body, scales, vertebrae or muscle. Analysis using polynomial regression of weight gain and gill Na+‐K+ ATPase activity and using the broken‐line regression of whole body K concentrations indicated that the adequate dietary K concentration for grass carp is about 9.45–9.99 g kg?1 diet.  相似文献   

4.
A growth trial was conducted to estimate the optimum concentration of dietary calcium (Ca) for grass carp (Ctenopharyngodon idella). Triplicate groups of grass carp (4.52 ± 0.02 g) were fed diets containing graded levels (2.75, 4.51, 6.24, 7.99, 9.66 and 11.5 g kg?1) of Ca for 8 weeks. Weight gain, feed efficiency and protein efficiency ratio were linearly increased up to the 7.99 g kg?1 dietary Ca and then maintained stable beyond this level (P < 0.05). Dietary Ca levels higher than 7.99 g kg?1 significantly increased the ash contents of whole body, vertebrae and scales. Ca contents in whole body, vertebrae and scales were linearly increased up to the 7.99 g kg?1 dietary Ca and then maintained stable beyond this level (P < 0.05). In contrast, dietary Ca levels higher than 9.66 g kg?1 significantly decreased Mg contents in whole body, vertebrae and scales. Dietary Ca levels higher than 7.99 g kg?1 significantly increased plasma alkaline phosphatase activity. However, plasma Ca, P and Mg contents were not significantly affected by dietary Ca supplements (P > 0.05). Polynomial regression analysis indicated that 10.4 g kg?1 dietary Ca was required for maximal tissue storage and mineralization as well as optimal growth.  相似文献   

5.
To study the effects of manganese on growth performance, digestive and absorptive abilities, as well as the antioxidative capacity in the hepatopancreas and intestine, young grass carp (Ctenopharyngodon idellus Val.) (264 ± 1 g) were fed diets containing graded levels of manganese at 3.65 (control), 8.62, 13.48, 18.24, 22.97 and 27.86 mg kg?1 diet for 8 weeks. Per cent weight gain (PWG) and feed intake were the poorest in fish fed the basal diet (P < 0.05). The activities of trypsin, lipase and alkaline phosphatase in the intestine were significantly enhanced with dietary manganese level at 13.48 mg kg?1 diet (P < 0.05). Additionally, in the hepatopancreas and intestine, the protein carbonyl and malondialdehyde contents were the lowest in fish fed the diet with dietary manganese level at 13.48 mg kg?1 diet (P < 0.05), while the anti‐hydroxyl radical capacities, manganese superoxide dismutase (MnSOD), glutathione peroxidase and glutathione‐S‐transferase activities were significantly enhanced with dietary manganese level at 13.48 mg kg?1 diet (P < 0.05). Moreover, the catalase activity and glutathione content in the intestine were the highest in fish fed the diet with dietary manganese level at 18.24 mg kg?1 diet (P < 0.05). These results indicated that optimum dietary manganese promoted growth, enhanced the digestive and absorptive abilities, and improved the antioxidative capacity in young grass carp. Based on the quadratic regression analysis for PWG and intestinal MnSOD activity, the manganese requirements for young grass carp with the initial body weight of 264 g were 16.91 and 18.21 mg kg?1 diet respectively.  相似文献   

6.
To investigate effects of iron (Fe) on growth, haematological parameters, flesh quality and antioxidant status in muscle, young grass carp (Ctenopharyngodon idella) (292.0 ± 3.2 g) were fed graded levels of Fe (20.7, 38.4, 52.8, 79.3, 98.0 and 120.0 mg kg?1 diet) for 8 weeks. Per cent weight gain (PWG) and feed intake were improved with Fe levels up to 52.8 mg kg?1 diet. Serum Fe, erythrocyte counts, haemoglobin (Hb), haematocrit and mean cell haemoglobin increased with optimal Fe levels (38.4–79.3 mg kg?1 diet) (P < 0.05). The muscle protein and lipid contents were increased by dietary Fe, whereas moisture, liquid loss, shear force and hydroxyproline contents followed opposite trends. Malondialdehyde and protein carbonyl contents in muscle were the lowest in fish fed the 52.8 or 79.3 mg Fe kg?1 diet, respectively, while superoxide dismutase, catalase, glutathione‐S‐transferase, glutathione peroxidase and glutathione reductase activities, and glutathione content were increased by Fe levels up to 52.8–79.3 mg kg?1 diet. Results indicated that the optimal Fe improved growth, flesh quality and muscle antioxidant defence of young grass carp. Dietary Fe requirements for PWG, serum Fe and Hb of young grass carp (292–695 g) were 73.5, 72.8 and 69.0 mg kg?1 diet, respectively.  相似文献   

7.
The effects of dietary phosphorus (P) on growth, body composition and immunity of young taimen (Hucho taimen) were studied. Six purified diets contained graded levels (2.3‐control, 4.0, 5.6, 7.5, 9.1 and 10.8 g kg?1 diet) of available P. Each diet was fed to triplicate groups of 30 fish with an initial average weight (55.31 ± 0.38) g for 84 days. The weight gain, specific growth rate and feed conversion ratio were improved by dietary available P up to 4.35 g kg?1 (P < 0.05) and then levelled off. Hepatosomatic index and body crude lipid content decreased significantly with increasing P levels, while ash contents and P concentrations in the whole body and vertebrae increased by dietary available P up to 4.36 and 4.44 g kg?1 and then levelled off respectively (P < 0.05). Liver superoxide dismutase and glutathione peroxidase and plasma alkaline phosphatase activities in the treatment groups were significantly higher compared with the control group (P < 0.05). Plasma IgM contents increased linearly with increasing dietary P from 4.0 to 9.1 g kg?1 group and then decreased. Dietary P supplementation reduced plasma triglyceride, malondialdehyde and liver malondialdehyde contents. There were no significant effects on plasma total protein, albumin, globulin, glucose, aspartate aminotransferase and alanine aminotransferase, catalase, lysozyme and liver catalase compared with the control group (P > 0.05). Broken line regression analysis indicated that dietary available P requirement was 4.34 and 4.35 g kg?1, based on weight gain and P concentration in the whole body respectively.  相似文献   

8.
This experiment was conducted to study the effects of different forms and levels of manganese (Mn) on the growth performance, antioxidant activities, tissue Mn content and cytosolic manganese superoxide dismutase (cMnSOD) gene expression of Litopenaeus vannamei. Treatments consisted of 0, 10, 20, 30, 40 and 60 mg Mn kg?1 from manganese sulphate (Mn‐S) and manganese methionine (Mn‐Met), providing the actual dietary value of 5.17, 15.62, 25.55, 34.22, 44.48 and 67.90 mg Mn kg?1 Mn‐S, and 5.17, 15.71, 25.36, 35.86, 45.16 and 65.06 mg Mn kg?1 Mn‐Met, respectively. Each diet was fed to triplicate groups of L. vannamei (initial body weight: 1.925 ± 0.002 g) in a recirculated fresh water rearing system for 8 weeks. Weight gain rate (WGR) increased in prawns provided with from 25.55 to 44.48 mg Mn kg?1 Mn‐S and 15.71 to 45.16 mg Mn kg?1 Mn‐Met and then declined above these levels. The lowest protein efficiency ratio (PER) and the highest feed conversion rate (FCR) were observed in prawns fed the control diet (P < 0.05) and showed no significant differences among other treatments (P > 0.05). Survival rate (SR) was not affected by the dietary treatments (P > 0.05). Total SOD and Mn‐SOD activities were higher in the hepatopancreas of prawns fed with Mn‐supplemented diets from 15.71 to 44.48 mg Mn kg?1 (P < 0.05). On the contrary, malondialdehyde (MDA) content was lower in the hepatopancreas of prawns fed the basal diet (P < 0.05). Mn concentrations in the hepatopancreas and muscles increased with increasing levels of dietary Mn supplementation. Moreover, Mn accumulation was lower in the muscle than in the hepatopancreas of the prawns. The mRNA expression of cMnSOD gene in the hepatopancreas of prawns was upregulated with increasing dietary Mn levels of Mn‐S from 25.55 to 44.48 mg Mn kg?1, Mn‐Met from 15.71 to 45.16 mg Mn kg?1 and then plateaued above these levels. Broken‐line regression analysis of WGR indicated that the optimal dietary Mn requirements for juvenile L. vannamei were 32.26 mg Mn kg?1 Mn‐S and 23.90 mg Mn kg?1 Mn‐Met, respectively.  相似文献   

9.
Two 8‐week feeding trials were conducted to evaluate dietary carbohydrate utilization by omnivorous gibel carp (Carassius auratus gibelio) (2.4 ± 0.1 g) and herbivorous grass carp (Ctenopharyngodon idellus) (6.5 ± 0.1 g). Five isonitrogenous (370 g kg?1) and isolipid (70 g kg?1) diets were formulated with increasing corn starch levels (60, 140, 220, 300 and 380 g kg?1). Results showed that specific growth rate (SGR), feed efficiency (FE) and protein retention efficiency (PRE) of gibel carp significantly increased from dietary starch of 60 to 300 g kg?1 and then decreased from 300 to 380 g kg?1, but those of grass carp showed no significant differences between treatments. Independent of dietary starch levels, grass carp gained significantly higher FE and PRE than gibel carp. Feeding rate (FR) of gibel carp was significantly higher than that of grass carp. In two fish species, high dietary starch (300 and 380 g kg?1) tended to obtain higher hepatosomatic index (HSI), serum triglyceride, hepatic lipid and body lipid contents. Serum glucose concentration of grass carp was not affected, while that of gibel carp fed the starch of 300 g kg?1 diet was significantly lower than those of the fish fed other four diets (60, 140, 220 and 380 g kg?1). Grass carp showed high tolerance to dietary starch while dietary corn starch should be no more than 300 g kg?1 for gibel carp. High starch contents may cause lipid accumulation in the liver and body.  相似文献   

10.
A feeding trial was conducted to evaluate the effects of dietary magnesium on the growth, carapace strength, tissue and serum Mg concentration of soft‐shelled turtles, Pelodiscus sinensis (Wiegmann). Juvenile soft‐shelled turtles of approximate 5.4 g body weight were fed diets with seven levels of Mg (48, 206, 369, 670, 955, 1195 and 1500 mg Mg kg?1) for eight weeks. No significant difference (P ≥ 0.05) was found in weight gain (WG), feed conversion ratio or protein efficiency ratio among treatments. However, the WG of turtles continued to increase with increasing dietary Mg levels up to 670 mg kg?1, beyond which the WG levelled off. The plasma alkaline phosphatase activity and the muscle, bone Mg concentrations of the turtles increased with the increasing dietary Mg levels between 48 and 955 mg kg?1, beyond which the tissue Mg concentrations remained relatively constant. Furthermore, the carapace strengths of turtles fed with the control diet of 48 mg Mg kg?1 were significantly weaker (P < 0.05) than that of turtles fed with diets containing higher Mg levels. Based on a broken‐line modelling analysis, the required dietary Mg level for the optimal WG of juvenile soft‐shelled turtles was estimated to be approximately 650 mg kg?1. By contrast, the required dietary Mg levels for turtles to reach the optimal muscle and bone Mg concentrations were 1050 and 1000 mg kg?1 respectively. The required dietary Mg level for maximal alkaline phosphatase activity was approximately 980 mg kg?1.  相似文献   

11.
A growth trial was conducted to evaluate the effects of chelated (Mintrex? Mn, Mn‐M) or inorganic (MnSO4·H2O, Mn‐S) manganese (Mn) on growth, feed utilization, tissue Mn deposition and liver superoxide dismutase (SOD) activity in turbot Scophthalmus maximus. A semi‐purified basal diet was formulated to be deficient in Mn (3.7 mg kg?1) and contained tricalcium phosphate and sodium phytate at levels of 20 and 5 g kg?1, respectively. Ten other diets were made by adding five levels (5, 10, 20, 35 and 55 mg Mn kg?1 diet) of either the Mn‐M or Mn‐S to the basal diet, respectively. The 11 experimental diets were fed to groups of turbot (mean initial weight: 4.6 g) for 8 weeks. Results showed that the specific growth rate (SGR), feed intake, whole body Mn/vertebra Mn concentration and Mn‐SOD activity in liver were significantly improved by Mn supplementation (P < 0.05). On the basis of SGR, vertebra Mn concentration or liver Mn‐SOD activity data, dietary Mn requirement was estimated to be 10.5, 46.3 or 12.9 mg kg?1 for turbot fed Mn‐S, and the same was estimated to be 7.6, 43.0 or 22.5 mg kg?1 for turbot fed Mn‐M, respectively. There was no significant difference in growth, feed intake, whole body Mn concentration or vertebra Mn concentration between the two dietary Mn sources (P > 0.05).  相似文献   

12.
A feeding trial was conducted to evaluate the optimum requirement of dietary available phosphorus (AP) for juvenile walking catfish, Clarias leather. Six practical diets were formulated to contain graded levels (2.2, 3.9, 5.5, 7.1, 8.8 and 10.4 g kg?1) of AP from dietary ingredients and monocalcium phosphate. Each diet was randomly fed to triplicate groups of fish with initial mean weight of 7.94 ± 0.08 g in floating cages (1.5 × 1.5 × 2.0 m) suspended in an earthen pond, and each cage was stocked initially with 60 fish. Fish were fed thrice daily (07:30, 13:00 and 17:30) to apparent satiation for 10 weeks. Both specific growth rate (SGR) and protein efficiency ratio significantly increased with increasing AP from 2.2 to 5.5 g kg?1 (P < 0.05) and then levelled off. Dietary AP levels significantly influenced whole‐body protein, lipid and ash contents as well as condition factor and hepatosomatic index (P < 0.05). Whole‐body and vertebrae phosphorus contents showed similar patterns as SGR in response to dietary AP content. Broken‐line analyses based on SGR, phosphorus contents in the vertebrae and whole‐body indicated the AP requirements were 5.8, 7.2 and 7.5 g kg?1, respectively.  相似文献   

13.
This study was conducted to compare the effects of manganese sulphate (Mn‐S), glycine manganese(Mn‐Gly) and manganese 2‐hydroxy‐4‐(methylthio)butyrate (Mn‐HMB) on juvenile cobia, Rachycentron canadum L. Treatments consisted of 0, 2, 4, 8, 16 or 32 mg supplemental Mn kg?1 from Mn‐S, Mn‐Gly or Mn‐MHB. Growth performance, manganese status, antioxidant activities and tissue mineral content were analysed after a 70‐day feeding period. Specific growth rate (SGR) increased with feeding 6.29 to 12.65 mg Mn kg?1 diet from the Mn‐S or 6.86 to 12.39 mg Mn kg?1 from the Mn‐Gly or 6.50 to 8.33 mg Mn kg?1 from the Mn‐HMB and then plateaued above these levels. Feed conversion ratio (FCR) show decreasing first and then increased trend. Survival rate (SR) were not affected by the dietary treatments (P > 0.05). Fish fed diets supplemented with manganese at levels of 4–32 mg Mn kg?1 had obviously higher hepatic Mn‐SOD activity (P < 0.05); on the contrary, hepatic has lower malondialdehyde (MDA) content (P < 0.05) than fish fed the basal diet. The manganese concentrations of whole body and vertebrae increased with increasing dietary Mn levels from 2–32 mg Mn kg?1 (independent on manganese sources). Dietary Mn supplementation did not significantly influence the copper concentrations of whole body and vertebrae, the zinc concentrations of whole body and liver. Analysis by the broken‐line regression of SGR indicated that the optimal dietary Mn requirements in juvenile cobia were 15.42, 11.22 and 10.50 mg Mn kg?1 diet from Mn‐S, Mn‐Gly or Mn‐HMB respectively.  相似文献   

14.
A 10‐week feeding trial was conducted in a flow‐through system to determine dietary choline requirement for juvenile gibel carp (Carassius auratus gibelio) (5.5 ± 0.1 g). Purified basal diet was formulated using vitamin‐free casein as protein source. Choline chloride was supplemented to the basal diet to formulate seven diets containing 76.1, 163, 356, 969, 1457, 2024 and 4400 mg kg?1 choline. Dietary methionine was 0.58%, less than the requirement (0.69%). The results indicated that specific growth rate (SGR) was higher in the fish fed 2024 mg kg?1 diet than the control group. Feeding rate and feed efficiency were not significantly affected. Protein productive value increased as dietary choline increased from 76.1 to 2024 mg kg?1 diet and was lower in the fish fed the diet containing 4400 mg choline kg?1 diet. Serum high‐density lipoprotein cholesterol (HDL‐C) and total cholesterol significantly increased with increasing dietary choline up to 1457 mg kg?1, and no differences were found with further increase. Fish carcass fat contents decreased significantly with increased dietary choline. Hepatic lipid contents increased with dietary choline up to 1457 mg kg?1 and then decreased. Quadric regression of SGR and plasma HDL‐C indicted dietary choline requirement was 2500 and 2667 mg kg?1 diet, respectively.  相似文献   

15.
A feeding trial was conducted for 8 weeks to evaluate the effects of supplemental phytic acid (PA) on the apparent digestibility and utilization of dietary amino acids (AAs) and minerals in juvenile grass carp. Five experimental diets consisted of graded levels of PA (0.2, 4.7, 9.5, 19.1 and 38.3 g kg?1, named as P0, P5, P10, P20 and P40). Triplicate groups of fish (initial weight, 22.37 ± 0.16 g) were fed twice daily (08:00 and 16:00 h). The crude protein content in whole body significantly (p < .05) decreased in fish fed with 19.1 and 38.3 g PA kg?1 diet. Supplemental PA (>4.7 g kg?1) significantly reduced the apparent digestibility coefficient (ADC) of AAs (Asp, Thr, Ser, Glu, Gly, Ala, Cys, Val, Met, Ile, Leu, Phe, Lys, Pro, His and Arg) and the ADC of minerals (P, Ca, Mg, Zn, Cu, Fe and Mn) in grass carp. The contents of minerals (P, Ca, Mg and Zn) in whole body and bone were also found to be significantly reduced in dietary PA > 4.7 g kg?1, while the bone ash, serum Alkp and Zn contents were found to be significantly decreased when the PA supplementation level was above 9.5 g kg?1, and the contents of serum Ca and Mg were found to be markedly altered in higher PA‐supplemented groups. The results indicated that supplemental PA decreased the apparent digestibility and utilization of AAs and minerals, and thus reduced the feed utilization of grass carp, suggesting that the level of total PA should be below 4.7 g kg?1 in grass carp diet.  相似文献   

16.
A 10‐week feeding trial was conducted to estimate the optimum dietary manganese requirement for juvenile cobia, Rachycentron canadum L. The basal diet was formulated to contain 501 g kg?1 crude protein from vitamin‐free casein, gelatin and fish protein concentrate. Manganese sulphate was added to the basal diet at 0 (control group), 6, 12, 18, 24 and 36 mg Mn kg?1 diet providing 5.98, 7.23, 16.05, 23.87, 28.87 and 41.29 mg Mn kg?1 diet, respectively. Each diet was randomly fed to three replicate groups of cobia for 10 weeks, and each tank was stocked with 30 fish (initial weight, 6.27 ± 0.03 g). The manganese concentration in rearing water was monitored during the feeding period and was < 0.01 mg L?1. Dietary manganese level significantly influenced survival ratio (SR), specific growth ratio (SGR), feed efficiency ratio (FER) and the manganese concentrations in the whole body, vertebra and liver of cobia. When the dietary manganese level rose from 5.98 mg kg?1 to 23.87 mg kg?1, the superoxide dismutase (SOD; EC 1.15.1.1) activities in liver also increased (P < 0.05). But there was no significant change in SOD activities for the groups fed with diets containing manganese level higher than 23.87 mg kg?1. On the basis of broken‐line regression of SGR, manganese concentration in whole body and vertebra the manganese requirements of juvenile cobia were 21.72 mg kg?1, 22.38 mg kg?1 and 24.93 mg kg?1 diet in the form of manganese sulphate, respectively.  相似文献   

17.
This study was conducted to investigate the effect of dietary manganese (Mn) on growth, vertebrae and whole‐body Mn content of juvenile grouper, and to examine the effect of dietary Mn on copper (Cu), iron (Fe), zinc (Zn), calcium (Ca), phosphorus (P) and magnesium (Mg) content of vertebrae and whole body. Seven casein‐gelatin‐based diets were supplemented with 0, 5, 10, 15, 20, 50 and 1000 mg kg?1 of Mn from MnSO4·H2O. Grouper with an initial weight of 12.9 ± 0.4 g were fed to satiation with one of the seven diets for 8 weeks. Growth was not significantly affected by dietary Mn supplements. Vertebrae Mn increased from 31.7 to 118.1 mg kg?1 dry weight with dietary Mn supplement increasing from 0 to 50 mg kg?1 (y = ?0.0002x3 + 0.0162x2 + 1.3903x + 26.27, R2 = 0.9561, where y is the vertebrae Mn content and x is the dietary Mn content). Whole‐body Mn increased from 2.5 to 7.8 mg kg?1 wet weight with dietary Mn supplement increasing from 0 to 50 mg kg?1 (y = 0.00001x3 ? 0.00107x2 + 0.11054x + 2.24615, R2 = 0.9080, where y is the whole‐body Mn content and x is the dietary Mn content). Dietary Mn had no significant effect on vertebrae Fe, Ca, P and Mg content, and whole‐body Cu, Zn and Mg content. However, vertebrae Zn and whole body Ca, P were highest in fish fed diet supplemented with 15 mg kg?1 of Mn. Based on this, Mn supplement of 15 mg kg?1 might be the optimum when the basal diet contained 4 mg kg?1 of Mn. Fish fed diet supplemented with 1000 mg kg?1 of Mn did not show any gross abnormality or change in feeding behaviour, but Mn contents of vertebrae and whole body were as high as 695.1 mg kg?1 dry weight and 42.5 mg kg?1 wet weight, respectively. Also, whole body Fe decreased significantly when Mn supplement was up to 1000 mg kg?1.  相似文献   

18.
Daidzein is widely used in farmed animals as a dietary additive. However, limited information is available about its use in aquaculture. The effects of daidzein inclusion in the diet of gibel carp was assessed in terms of growth performance, immune response, disease resistance, antioxidant activity, hormone levels, daidzein tissue residues, as well as intestinal and liver morphology. The dietary daidzein inclusion levels were 0, 40, 200 and 400 mg kg?1 and six replicates of 30 fish were used for each group. No mortality was observed during the 80‐day feeding trial. The growth performance of experimental fish was not significantly affected by dietary daidzein supplementation. However, the non‐specific immune responses, resistance to Aeromonas hydrophila, antioxidant activities, 17β‐oestradiol level, vitellogenin concentration, gonadosomatic index (GSI) and intestinal morphology were significantly affected by dietary daidzein. A dietary dose of 400 mg kg?1 daidzein significantly decreased the GSI, increased 17β‐oestradiol and vitellogenin concentrations, and impaired the intestinal structure. The daidzein residue in muscle of gibel carp was increased by the high level (400 mg kg?1) of dietary daidzein. Equol was not detected in fish muscle among all treatments. The present study proved that 40 mg kg?1 daidzein was safe to be included in diets of gibel carp, and a safety margin of 5 folds of the use‐level (40 mg kg?1) was determined.  相似文献   

19.
A 49‐days feeding trial was conducted to study the effects of sodium butyrate on growth performance, gut morphology of juvenile grass carp. Five isoenergetic and isonitrogenous experimental diets were compounded by the supplementation in the basal diet with gradient sodium butyrate at 0, 500, 1000, 2000, 3000 mg kg?1 respectively. A total of 375 juvenile grass carp (with initial body weight of 3.8 g) were randomly allocated into five diet treatments, and each treatment has three replicates. The results showed that the specific growth rate (SGR) of SB1000 and SB2000 group was significantly higher (P < 0.05) than that of the other groups. Moreover, the lowest SGR was observed in SB3000 group. Feeding rate and the whole‐body proximate composition including moisture, crude lipid, crude protein and crude ash were not affected by sodium butyrate (P > 0.05). Total superoxide dismutase activities in hepatopancreas in the experimental groups were significantly higher than those in the control group (P < 0.05). Glutathione peroxidase activity in hepatopancreas was significantly upregulated by dietary sodium butyrate level (P < 0.05). However, the activity of total antioxidant capacity and the contents of malondialdehyde were not significantly different among groups. The expression levels of mRNA encoding PepT1 and LAT2 in the foregut both showed a first increasing and then decreasing tendency as dietary sodium butyrate level increased (P < 0.05), and peaked in SB1000 and SB2000 groups respectively. The results indicated that appropriate dietary supplementation of sodium butyrate at 2000 mg kg?1 could improve the growth, antioxidant ability and intestinal absorption capacity of the juvenile grass carp.  相似文献   

20.
A 75 days experiment was conducted in a flow‐through system on juvenile gibel carp (Carassius auratus gibelio) (3.43 ± 0.01 g) to evaluate the effects of dietary lysozyme on growth performance, intestine morphology, microbiota and immune response. Four isonitrogenous (crude protein: 367 g kg?1) isolipid (62 g kg?1) and isocaloric (gross energy: 17.92 kJ g?1) diets were formulated to contain 0, 100, 500 and 1000 mg kg?1 lysozyme, respectively. The results showed that specific growth rate (SGR) and feed efficiency (FE) increased at 1000 mg kg?1 lysozyme. Blood leucocyte phagocytic activity (PA) and serum lysozyme (LZM) decreased with dietary lysozyme on day 25, 50 and 75. There were no significant differences in alternative complement pathway (ACP), respiratory burst (ROS), serum superoxide dismutase (SOD), glutathione peroxidase (GSHpx) or malonaldehyde (MDA). After Aeromonas hydrophilia challenge, higher survival was obtained at 500 mg kg?1 group. PA, ROS, SOD, LZM and ACP increased with increasing dietary lysozyme, while MDA reversed. Goblet cells in mid‐intestine and microvilli height in distal intestine increased with dietary lysozyme on day 75. Dietary lysozyme reduced the diversity of intestine microbiota. In conclusion, oral administration of 500 mg kg?1 dietary lysozyme for 75 days is recommended for the survival of gibel carp and 1000 mg kg?1 dietary lysozyme for fast growth.  相似文献   

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