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1.
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   

2.
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   

3.
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   

4.
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   

5.
A growth trial was conducted to estimate the optimum concentration of dietary Manganese (Mn) for grass carp (Ctenopharyngodon idella). Triplicate groups of grass carp (3.97 ± 0.05 g) were fed diets containing graded levels (4.0, 8.9, 13.8, 18.7, 23.6 and 33.3 mg kg?1) of Mn for 8 weeks. Weight gain, specific growth rate and feed efficiency were linearly increased up to the 18.7 mg kg?1 dietary Mn and then levelled off beyond this level. For body composition, lipid contents in whole body, muscle and liver decreased significantly with increasing dietary Mn level. Grass carp fed with dietary Mn levels higher than 19.7 mg kg?1 significantly decreased condition factor. Whole body, vertebrae and scales mineralization were all affected significantly by dietary Mn levels. Mn contents in whole body, vertebrae and scales were linearly increased up to the 18.7 mg kg?1 dietary Mn and then levelled off beyond this level. Contrarily, Ca and P contents seem to be inversely related to dietary Mn. However, dietary Mn levels had no significant effect on body Fe contents. Broken‐line analysis indicated that 20.6 mg kg?1 dietary Mn was required for maximal tissue Mn storage, as well as satisfied for the optimal growth of juvenile grass carp.  相似文献   

6.
Two, 8‐week feeding trials were conducted to compare protein‐sparing capability of dietary lipid in herbivorous grass carp (Ctenopharyngodon idella) and omnivorous tilapia (Oreochomis niloticus × O. aureus). Utilizing a 2 × 3 factorial design, experimental diets containing two levels of crude protein (380 and 250 g kg−1) and three levels of lipid (0, 40 and 100 g kg−1) were formulated for use in both feeding trials. Growth performances showed better response of both fish fed 380 g kg−1 protein diet than those fed 250 g kg−1 protein diet. Despite the dietary protein level, weight gain (WG), specific growth ratio (SGR), feed conversion ratio (FCR) and protein efficiency ratio were much higher (P < 0.05) for grass carp fed 40 g kg−1 lipid diet than those fed 100 g kg−1 lipid diet; however, there were no significant differences in tilapia fed the two diets. The feed intake of grass carp fed lipid‐free diet was the lowest, but it tended to decrease with increase in dietary lipids in tilapia. Lipid retention (LR) was negatively correlated with dietary lipid concentration of both fish. Viscerosomatic index (VSI), hepatosomatic index (HSI), intraperitoneal fat ratio (IPF) and whole‐body and liver lipid content positively correlated with dietary lipid concentration of both fish. Plasma parameters and liver enzymes activities were also positively correlated with dietary lipid concentration of both fish. Liver lipid contents were higher and enzymes activities were lower in grass carp when compared with tilapia. These data suggested that there was no evidence of a protein‐sparing effect of dietary lipids in grass carp. Tilapia has relatively higher capacity to endure high dietary lipid level compared to grass carp.  相似文献   

7.
D. Xie  D. Han  X. Zhu  Y. Yang  J. Jin  H. Liu  S. Xie 《Aquaculture Nutrition》2017,23(5):1104-1112
A nine‐week feeding experiment was conducted in flow‐through system with gibel carp (43.8 ± 0.2 g) to study the effects of dietary available phosphorus (P) on growth, phosphorous digestibility and intestinal enzyme activities. Seven semipurified diets were formulated to contain 0.8 (the basal), 2.4, 3.6, 6.1, 7.4, 10.1 and 15.8 g available phosphorus kg?1 diet. The results showed that specific growth rate and feed efficiency increased with increasing dietary available P from 0.8 to 7.4 g P kg?1. Fish body ash increased with increasing dietary available P, while moisture, protein content or energy content had no difference. Total phosphorus waste discharging (TPW) increased with increased dietary phosphorous. Plasma glucose was higher in the fish fed with 7.4 g kg?1 P. Plasma triglycerides was lower in fish fed diets containing 6.1–10.1 g kg?1 P. No significant effects were observed in plasma P and Ca (p > .05). The activities of intestinal amylase, lipase and trypsin showed no difference, while AKP and Na+, K+‐ATPase activities decreased with increasing dietary available P. In conclusion, based on the regression between specific growth rate (SGR), P retention efficiency, feed efficiency (FE) and dietary available P, the available P requirements for on‐growing gibel carp were 10.69, 8.22 and 6.72 g kg?1, respectively.  相似文献   

8.
To determine dietary magnesium (Mg) requirements of juvenile grass carp, Ctenopharyngodon idella, magnesium sulphate was added to the basal diet at 0, 150, 300, 600, 1200, 2400 mg Mg kg−1 diet. Each diet was fed to three replicate groups of juvenile grass carp (initial weight: 7.69 ± 0.13 g) in a closed, recirculating rearing system for 76 days. No mortality or nutritional deficiency signs were observed except the growth depression in fish fed the Mg‐deficient diet. Growth performance and activities of serum superoxide dismutase (SOD), glutathione peroxidase (GPx) and lysozyme (LSZ) were highest (P <0.05) in fish fed the diet supplemented with 600 mg Mg kg−1. The serum malondialdehyde (MDA) content was higher (P <0.05) in fish fed the diets supplemented with 0 and 150 mg Mg kg−1 than that in fish fed the diets with ≥300 mg Mg kg−1. Mg concentrations both in whole‐body and vertebrae increased with the increase in dietary Mg level up to 300 mg kg−1, whereupon the response reached a plateau. Analysis by second‐order polynomial regression of weight gain, by broken‐line regression of vertebrae Mg concentration and by linear regression of whole‐body Mg retention of fish indicated that the adequate dietary Mg concentration for juvenile grass carp was 713.5, 627.7 and 469.8 mg kg−1 diet, respectively.  相似文献   

9.
A growth trial was conducted to estimate the optimum requirement of dietary available phosphorus (P) for Chinese sucker juveniles. Triplicate groups of juveniles Chinese sucker (initial mean weight: 1.77 ± 0.02 g, mean ± SD) were fed diets containing graded levels (3.1, 5.3, 7.5, 9.6 and 11.8 g kg?1) of available phosphorus. The basal diet (diet 1), containing 3.1 g kg?1 available P, was supplemented with graded levels of monocalcium phosphate to formulate four experimental diets. The fish were fed twice daily (08:00 and 17:00 h) to satiation for 8 weeks. During the experimental period, the water temperature fluctuated from 27.5 to 30.5 °C and dissolved oxygen was more than 6 mg L?1. The specific growth rate, protein efficiency ratio were all significantly increased by dietary available phosphorus up to 7.5 g kg?1 (P < 0.05) and then levelled off beyond this level. Feed conversion ratio significantly decreased with dietary available phosphorus level up to 7.5 g kg?1 (P < 0.05). Dietary treatments did not significantly affect feed intake (P > 0.05). Efficiency of phosphorus (P) utilization significantly decreased with dietary available phosphorus level (P < 0.05). Body composition analysis showed that the whole‐body lipid, ash, calcium, phosphorus, magnesium (Mg), zinc (Zn) and copper (Cu) contents were all significantly affected by dietary available P concentration (P < 0.05); however, no significance were found for manganese (Mn) concentration and calcium/phosphorus (Ca/P) ratios in whole‐body among all the treatments (P > 0.05). Dietary phosphorus levels also significantly affected the mineralization of vertebrae and scale (P < 0.05), and Ca/P ratios in scale were not influenced by dietary P supplementation, while vertebrae Ca/P ratio decreased with dietary available P levels (P < 0.05) (quadratic effect, P < 0.001). Signs of phosphorus deficiency were characterized by poor growth, slightly reduced mineralization and an increase in body lipid content. The blood chemistry analysis showed that dietary available P had distinct effects on enzyme activities of alkaline phosphatase, as well as contents of triacyglycerol and total cholesterol (P < 0.05). Broken‐line analysis based on weight gain indicated the minimum available phosphorus requirement for the optimal growth of juvenile Chinese sucker was 7.4 g kg?1. Based on the phosphorus content in whole body, vertebrae or scale indicated that the requirements were 8.3, 8.8 and 8.6 g kg?1 respectively.  相似文献   

10.
A feeding trial was conducted to investigate the effects of different levels of calcium (Ca) on growth and tissue mineralization in Japanese seabass, Lateolabrax japonicus. Six experimental diets were formulated to contain different levels of Ca (2.9, 4.2, 6.5, 7.9, 10.2 and 31.0 g kg?1) from dietary ingredients and Ca‐lactate·5H2O. The diets were fed to three triplicate groups of Japanese seabass (initial weight, 12.5 ± 0.0 g) for 56 days. Dietary Ca had no significant effect on survival or feed efficiency; however, the highest Ca (31.0 g kg?1) diet significantly reduced weight gain, feeding rate and whole‐body and muscle protein and lipid contents, as well as serum Ca concentration and alkaline phosphatase activity. A significant reduction in vertebral Ca, P, Zn, Fe and Mn contents and scale Ca, P, Mg and Mn contents was observed in Japanese seabass as dietary Ca level increased. Deformed fish were primarily found in the 2.9 and 31.0 g Ca kg?1 groups, indicating that these fish had poor bone mineralization.  相似文献   

11.
A 9‐week feeding trial was carried out with juvenile Jian carp (Cyprinus carpio var. Jian) to study the effects of dietary phosphorus on growth, body composition, intestinal enzyme activities and microflora. Quadruple groups of juvenile Jian carp (7.17 ± 0.01 g) were fed practical diets containing available phosphorus 1.7 (unsupplemented control), 3.6, 5.5, 7.3, 9.2 and 11.0 g kg?1 diet to satiation. Feed intake, specific growth ratio and feed efficiency were the lowest in fish fed the basal diet (P < 0.05). Body moisture, protein, lipid content and ash were all significantly affected by dietary available phosphorus levels (P < 0.05). Activities of trypsin, amylase, Na+, K+‐ATPase, alkaline phosphatase and gamma‐glutamyl transpeptidase were improved with increasing dietary phosphorus levels. Intestinal Aeromonas and Escherichia coli decreased with increasing dietary phosphorus up to 3.6 and 5.5 g kg?1 diet respectively (P < 0.05), while Lactobacillus increased with the increasing dietary phosphorus up to 9.2 g kg?1 diet (P < 0.05). These results suggested that phosphorus could enhance intestinal enzyme activities of juvenile Jian carp and the minimum dietary available phosphorus requirement for SGR of juvenile Jian carp (7.2–63.8 g) was 5.2 g kg?1 diet.  相似文献   

12.
Herbivorous grass carp (Ctenopharyngodon idella) has been reported to exhibit low capacity to utilize high dietary lipid, but different lipid sources might affect this limited capacity. In order to compare the effects of different lipid sources with different lipid levels, juvenile grass carp were fed one of nine diets containing three oils [lard, plant oil mixed by maize and linseed oil, and n‐3 high unsaturated fatty acid‐enriched (HUFA‐enriched) fish oil] at three lipid levels (20, 60 and 100 g kg?1 dry diet) for 8 weeks. Decreased feed intake, poor growth performance, hepatic pathology and higher blood lipid peroxidation were found in 60 and 100 g kg?1 fish oil groups. Conversely, in lard and plant oil groups, even at 100 g kg?1 dietary lipid level, feed intake and growth performance did not decrease, despite histological observation revealed hepatic pathology in these groups. Plasma triglyceride and cholesterol contents increased significantly in all 100 g kg?1 dietary lipid groups. In the comparison of hepatic FA β‐oxidation among three oil groups at 60 g kg?1 dietary lipid level, impaired mitochondrial and peroxisomal FA oxidation capacity was observed in fish oil group. The results confirmed the relatively low capacity of grass carp to utilize high dietary lipid, and furthermore excess HUFA intake will result in more serious adverse effects than other FA.  相似文献   

13.
A 76‐day feeding trial was carried out to evaluate the effects of Lysine and Methionine supplementation on growth and digestive capacity of grass carp (Ctenopharyngodon idella) fed plant protein diets using high‐level canola meal (CM). Fish with initial average weight 103.9 ± 0.6 g were fed three extruded diets. Fish meal (FM) diet was formulated as the normal control with 40 g kg?1 FM and 300 g kg?1 CM; CM diet was prepared by replacing all FM with CM (total 340 g kg?1) without Lys or Met supplementation; CM supplement (CMS) diet was similar to CM diet but was supplemented with essential amino acids (EAA) to ensure the levels of Lys and Met similar to those in the FM diet. Feed intake, feed efficiency and specific growth rate of the grass carp fed CMS and FM diets were similar (P > 0.05), but higher than those of the grass carp fed CM diet (P < 0.05). The hepatosomatic index, relative gut length, intestosomatic index and intestinal folds height were significantly improved in fish fed FM and CMS diets as compared to CM diet (P < 0.05). Lower activities of trypsin, lipase and amylase in hepatopancreas were observed in fish fed CM diet (P < 0.05). Three hundred and forty gram per kilogram CM without Lys or Met supplementation significantly decreased trypsin, lipase and amylase mRNA levels in hepatopancreas (P < 0.05). These results indicated that the high supply of CM (340 g kg?1) in plant protein (200 g kg?1 soybean meal and 100 g kg?1 cottonseed meal) diets decreased digestive ability through decreasing digestive enzyme activities and enzyme gene's expressions of grass carp, and these side effects can be reversed by supplementing Lys and Met. Therefore, CM could be high level used in a plant protein blend‐based extruded diet for grass carp as long as EAA were supplemented.  相似文献   

14.
An 11‐week growth trial was conducted to determine dietary myo‐inositol (MI) requirement for juvenile gibel carp (Carassius auratus gibelio). Myo‐inositol was supplemented to the basal diet to formulate six purified diets containing 1, 56, 107, 146, 194 and 247 mg MI kg?1 diet, respectively. Each diet was fed to triplicate groups of juvenile gibel carp (initial body weight 3.38 ± 0.27 g, mean ± SD) in a flow‐through system. The diets were randomly assigned to different fish tanks. Fish fed ≥ 107 mg MI kg?1 diet had significantly higher weight gain (WG), feed efficiency (FE) and protein efficiency ratio than those fed 1 mg MI kg?1 diet. Fish fed ≥ 56 mg MI kg?1 diet had higher feeding rate and survival compared with fish fed 1 mg MI kg?1 diet. Dietary supplemental inositol did not affect fish liver inositol concentration. Fish fed ≥ 56 mg MI kg?1 diet had higher body dry matter, crude protein and gross energy and lower hepatosomatic index than fish fed 1 mg MI kg?1 diet. Dietary inositol supplementation decreased fish body ash. Quadratic regression of weight gain indicated that the myo‐inositol requirement to maximum growth for juvenile gibel carp was 165.3 mg MI kg?1 diet.  相似文献   

15.
A 100‐day growth trial was executed to determine the dietary selenium (Se) requirement of juvenile gibel carp (Carassius auratus gibelio). Selenomethionine was supplemented to casein‐gelatin diets at 0, 0.1, 0.25, 0.5, 1.0, 2.5 and 5 mg Se kg?1, respectively. Each of these seven semi‐purified diets containing 0.34, 0.47, 0.66, 0.82, 1.23, 2.77 and 5.13 mg Se kg?1 was fed to triplicate groups of gibel carp (2.74 ± 0.02 g) in a flow‐through system. No behaviour abnormalities and no mortality were found in fish exposed to dietary Se concentrations. With the increasing dietary Se supplemented concentrations, weight gain of fish remarkably increased at the levels of ≤1 mg Se kg?1 diet and then showed no significant difference above 1 mg Se kg?1 levels. Although growth performances (weight gain, hepatosomatic index, condition factor and survival) were not impaired in gibel carp fed at above the levels of 2.5 mg Se kg?1, indicators of oxidative stress were changed significantly. Serum superoxide dismutase (SOD) activities significantly declined, hepatic glutathione peroxidase (GPx) activities significantly increased and the tissue Se concentrations significantly raised at the highest supplemented level of 5 mg Se kg?1. A clear linear relationship between Se‐depended GPx activities and hepatic Se concentrations was observed. The present results indicated that the dietary Se requirement for gibel carp is 1.18 mg Se kg?1 diet based on weight gain, GPx activities and tissue accumulation.  相似文献   

16.
A 63‐day growth trial was undertaken to estimate the effects of supplemented lysine and methionine with different dietary protein levels on growth performance and feed utilization in Grass Carp (Ctenopharyngodon idella). Six plant‐based practical diets were prepared, and 32CP, 30CP and 28CP diets were formulated to contain 320 g kg?1, 300 g kg?1 and 280 g kg?1 crude protein without lysine and methionine supplementation. In the supplementary group, lysine and methionine were added to formulate 32AA, 30AA and 28AA diets with 320 g kg?1, 300 g kg?1 and 280 g kg?1 dietary crude protein, respectively, according to the whole body amino acid composition of Grass Carp. In the groups without lysine and methionine supplementation, weight gain (WG, %) and specific growth rate (SGR, % day?1) of the fish fed 32CP diet were significantly higher than that of fish fed 30CP and 28CP diets, but no significant differences were found between 30CP‐ and 28CP‐diet treatments. WG and SGR of the fish fed 32AA and 30AA diets were significantly higher than that of fish fed 28AA diets, and the performance of grass carp was also significantly improved when fed diets with lysine and methionine supplementation (P < 0.05), and the interaction between dietary protein level and amino acid supplementation was noted between WG and SGR (P < 0.05). Feed intake (FI) was significantly increased with the increase in dietary protein level and the supplementation of lysine and methionine (P < 0.05), but feed conversion ratio (FCR) showed a significant decreasing trend (P < 0.05). Two days after total ammonia nitrogen (TAN) concentration test, the values of TAN discharged by the fish 8 h after feeding were 207.1, 187.5, 170.6, 157.3, 141.3 and 128.9 mg kg?1 body weight for fish fed 32CP, 32AA, 30CP, 30AA, 28CP and 28AA diets, respectively. TAN excretion by grass carp was reduced in plant‐based practical diets with the increase in dietary protein level and the supplementation of lysine and methionine (P < 0.05). The results indicated that lysine and methionine supplementation to the plant protein sources‐based practical diets can improve growth performance and feed utilization of grass carp, and the dietary crude protein can be reduced from 320 g kg?1 to 300 g kg?1 through balancing amino acids profile. The positive effect was not observed at 280 g kg?1 crude protein level.  相似文献   

17.
Six isonitrogenous (390 g kg?1) and isoenergetic (16.2 kJ g?1) diets with varying carbohydrate : lipid (CHO : L) ratios (202.5–1.74), were fed to triplicate groups of 25 fish in indoor recirculation system. Over 8‐week‐growth trial, best weight gain (WG), specific growth rate, feed conversion ratio, protein efficiency ratio and protein production value (P < 0.05) were observed in fish‐fed diets with CHO : L ratio of 7.5. Fish fed either the lowest (1.7) or highest (202.5) CHO : L ratio tended to produce lower (P < 0.05) growth and feed conversion efficiencies. The values of viscerosomatic index, hepatosomatic index and intraperitoneal fat ratio increased as dietary CHO : L ratios decreased. There were no significant differences in whole body and liver crude protein among dietary treatments. Whole body and liver lipid increased as CHO : L ratios decreased. Plasma cholesterol and triacylglyceride levels increased linearly as dietary CHO : L ratios decreased. Activities of glucokinase and pyruvate kinase were stimulated by elevated levels of dietary carbohydrate; however, activities of lipase (LPS) and alkaline phosphatase were stimulated by elevated levels of dietary lipid. Based on a second‐order polynomial regression analysis of WG against dietary carbohydrate and lipid levels, 275 g kg?1 of carbohydrate and 59 g kg?1 of lipid, corresponding to a CHO : L ratio of 4.7, in a diet holding 390 g kg?1 of crude protein and 16.3 kJ g?1 of gross energy, proved to be optimal for grass carp. These results indicated that utilization of dietary lipid and carbohydrate was moderate in grass carp, but the fish were a little more capable of utilizing lipid compared with carbohydrate.  相似文献   

18.
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   

19.
A ten‐week feeding trail was conducted to investigate the effects of increasing DL‐methionine (Met) supplementation on the success of fish meal (FM) replacement with plant proteins in practical diets for juvenile gibel carp, Carassius auratus gibelio. Twelve isoenergetic diets were formulated including two 150 g kg?1 FM diets (Diet 1—positive control 1 reflecting a commercial diet and Diet 2—positive control 2 reflecting a commercial diet but with balanced essential amino acid (EAA) profile) and ten 50 g kg?1 FM diets (negative controls) supplemented with graded levels (0–3.0 g kg?1) of DL‐Met (Diets 3–12). Each diet was fed to triplicate groups of gibel carp, near satiation four times daily for 10 weeks. Diet 2 with balanced EAA profile produced better final weight, specific growth rate (SGR) and feed conversion ratio (FCR) than the negative control diet containing no supplemental Met (Diet 3), but did not significantly differ from Diet 1. However, DL‐Met supplementation (0.5–3.0 g kg?1) in the negative control diets (Diets 4–12) produced growth performances similar to those fed the positive control diets (Diets 1 and 2). Based on quadratic regression analysis, the optimal dietary Met level with 5.2 g kg?1 of dietary cysteine (Cys) was found to be 7.1 g kg?1 dry diet for SGR and FCR. The corresponding total sulphur amino acid requirements (Met + Cys) of this species were calculated to be 12.3 g kg?1 dry diet for SGR and FCR. DL‐Met supplementation in 50 g kg?1 FM diets showed a decreasing trend in plasma cholesterol contents (p < .05). No significant differences were observed in whole‐body composition, plasma protein, triglyceride and free EAA contents among dietary treatments, while plasma aspartate transaminase, albumin and ammonia contents were significantly influenced by dietary Met levels. Juvenile gibel carp grew equally well on 150 g kg?1 FM diet or 50 g kg?1 FM diets balanced for EAA profile with supplemental amino acids. The results of this study overall indicate that balancing dietary amino acid levels with DL‐Met supplementation is a key strategy in successfully reducing FM levels in the diets of gibel carp.  相似文献   

20.
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   

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