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1.
The present study was conducted to investigate the effects of dietary lipid, carbohydrate and their interactions on growth performance, feed utilization, body composition and non‐specific immunity of large yellow croaker (Larimichthys crocea). The experimental fish were fed the diets with graded levels of dietary crude lipid (80, 110 and 140 g/kg diet) and dietary carbohydrate (60, 90 and 120 g/kg diet) for 7 weeks. Results showed that the specific growth rate decreased significantly as dietary carbohydrate increased, which partly resulted from the progressively reduced feed intake and protein efficiency ratio. Meanwhile, the result of postprandial glucose content confirmed glucose intolerance of the croaker. However, the specific growth rate was not significantly altered by dietary lipid, but the feed intake was remarkably reduced. The different growth performance and feed utilization of croaker in response to dietary lipid and carbohydrate resulted in the variation of body composition. In addition, the activity of lysozyme and classical complement pathway was significantly improved in croaker fed the diet with 110 g/kg lipid. In above, dietary carbohydrate and lipid of large yellow croaker should be maintained at 60 and 110 g/kg diet, respectively, based on the above indices.  相似文献   

2.
An 8‐week feeding trial was conducted to assess the interaction between dietary protein levels and fish growth, digestibility and activity of immunity‐related enzymes of Plectropomus leopardus. Five diets with different protein levels (400 g/kg, 450 g/kg, 500 g/kg, 550 g/kg and 600 g/kg protein) were designed. P. leopardus fed with 500 g/kg, 550 g/kg and 600 g/kg dietary protein, showed higher weight gain rates than fish fed 400 g/kg and 450 g/kg dietary protein. Ingestion rate in fish fed with 500 g/kg dietary protein was significantly higher than those with other diets. P. leopardus fed with 500 g/kg, 550 g/kg and 600 g/kg dietary protein, showed that feed coefficients were significantly lower than those fed with 400 g/kg and 450 g/kg dietary protein. Net protein utilization was significantly lower in fish fed with 400 g/kg diet than those with other diets. Fish fed with 400 g/kg and 450 g/kg dietary protein had an apparent feed digestibility coefficient for dry matter that was significantly lower than that with other diets. Protease activity was highest in fish fed on 500 g/kg dietary protein. Fish fed with 500 g/kg dietary protein, had the highest superoxide dismutase activity. Fish fed with 600 g/kg dietary protein, had the highest alkaline phosphatase activity. Thus, a diet containing 500 g/kg protein is recommended for P. leopardus aquaculture.  相似文献   

3.
A 12‐week feeding trial was conducted to determine the dietary phosphorus requirement of Heteropneustes fossilis fingerlings (7.7 ± 0.04 g). Fish were fed casein–gelatine‐based purified diets in triplicate groups near satiation with seven different levels of dietary phosphorus (3.2, 5.2, 7.2, 9.2, 11.2, 13.2 and 15.2 g/kg dry diet). All diets were formulated to be isoproteic (400 g/kg) and isoenergetic (17.89 kJ/g). Highest absolute weight gain (68.38 g/fish), best feed conversion ratio (1.48), protein retention efficiency (30.74%), protein gain (12.44 g/fish), haemoglobin (11.19 g/dL), RBCs (3.12 x106/mm3), haematocrit (33.44%) and serum phosphate (2.82 mg/L) were found at 9.2 g/kg phosphorus. Hepatic superoxide dismutase and catalase activity were also significantly influenced by the dietary phosphorus levels. Whole body and vertebrae phosphorus concentrations increased significantly as the amount of dietary phosphorus increased from 3.2 to 11.2 g/kg dry diet and then plateaued. More accurate information on dietary phosphorus requirement was obtained by subjecting the AWG, FCR, vertebrae phosphorus and whole body phosphorus concentrations data against various levels of dietary phosphorus to broken‐line analysis, which yielded the requirement in the range of 9.0–11.0 g/kg for optimum growth and mineralization of H. fossilis.  相似文献   

4.
Dietary phosphorus requirement of fingerling Labeo rohita (6.1 ± 0.13 cm; 1.88 ± 0.05 g) was quantified by feeding seven isonitrogenous (350 g/kg crude protein) and isocaloric (16.72 kJ/g gross energy) purified diets with different levels of phosphorus as 3.5 (basal diet), 4.6, 5.7, 6.5, 7.8, 8.9, and 10.1 g/kg. Triplicate groups of fish were fed at 0800, 1200, and 1600 h to apparent satiation for 8 wk. Live weight gain (LWG; 494.68%), specific growth rate (3.18%/d), feed conversion ratio (1.54), feed efficiency (0.65), protein gain (PG; 1.26 g/fish), protein efficiency ratio (1.86), and phosphorus utilization efficiency (98.78%) improved significantly (P < 0.05), with increasing dietary phosphorus level up to 6.5 g/kg. However, phosphorus contents of vertebrae and scale increased significantly up to 7.8 g/kg. Dietary phosphorus levels significantly affected serum phosphorus concentration and alkaline phosphatase activity. Broken‐line analysis based on LWG; PG; and whole‐body, vertebrae, and scale phosphorus against dietary phosphorus indicated the optimal phosphorus requirement of fingerling L. rohita at 6.56, 6.58, 6.56, 8.02, and 8.44 g/kg diet, respectively. In order to restrict superfluous phosphorus in the diet, inclusion of 6.56 g/kg phosphorus is recommended for optimal growth of fingerling L. rohita.  相似文献   

5.
A two‐factor orthogonal test was conducted to determine the dietary vitamin E (VE, dl ‐α‐tocopheryl acetate) requirement for sub‐adult GIFT strain of Nile tilapia (Oreochromis niloticus) at two lipid levels, and evaluate its effect on antioxidant responses. A basal diet containing 60 or 130 g/kg of soybean oil was supplemented with 0, 20, 40, 60, 120 and 240 mg VE/kg, respectively. Each diet was fed to three replicate groups of tilapia with initial weight (80.3 ± 0.7) g for 10 weeks. Results showed that the weight gain, feed efficiency and hepatic VE retention of fish were significantly increased by the increased VE in diets. In groups with 60 and 130 g/kg lipid, fish fed diets supplemented with VE had higher serum superoxide dismutase (SOD) and catalase activity, and lower malondialdehyde content than fish fed the VE un‐supplemented diet (p < .05). The proximate composition of fish had no significant difference in the group with 130 g/kg lipid, whereas crude lipid and ash content were significantly affected by dietary VE in the group with 60 g/kg lipid. Based on broken‐line regression analysis, dietary VE requirement to support the maximum weight gain and serum SOD were 43.2–45.8 and 66.0–76.1 mg/kg in diets with 60 and 130 g/kg lipid, respectively.  相似文献   

6.
The dietary total and available requirement of tryptophan of Nile tilapia fingerlings was determined using linear regression analysis. Six hundred fish (3.4 ± 0.0 g) were fed diets containing 296.4 g/kg of crude protein and 14.1 MJ/kg of digestible energy. Five extruded diets containing 2.5, 3.0, 3.4, 3.8 and 4.2 g/kg of total tryptophan were evaluated. Fish were fed four times a day during 45 days. Final body weight, weight gain, feed intake, feed conversion ratio and net protein utilization of fish fed Trp 3.4 and Trp 3.8 diets were improved compared to fish fed Trp 2.5 and Trp 4.2 diets. No significant differences in survival rate, whole‐body moisture and ash were observed. Whole‐body amino acid profile of fish fed different diets did not differ statistically (p > .05). Fish fed Trp 3.0 and Trp 3.4 diets showed higher tryptophan retention compared to fish fed Trp 2.5 and Trp 4.2 diets. Excepting blood glucose, no effects of dietary tryptophan on haematological parameters were observed. The dietary total tryptophan requirement of Nile tilapia fingerlings based on weight gain was estimated to be 3.4 g/kg (11.0 g/kg of dietary crude protein) or 3.0 g/kg of available tryptophan (11.0 g/kg of dietary digestible protein).  相似文献   

7.
An 8‐week feeding trial was conducted to determine dietary lysine requirement of juvenile Pseudobagrus ussuriensis (initial body weight: 0.60 g). Six isonitrogenous (crude protein, 400 g/kg) and isolipidic (crude lipid, 50 g/kg) diets were formulated to contain graded levels of dietary lysine (12.8, 19.9, 26.5, 34.0, 40.8 and 44.1 g/kg dry diets, respectively). The results indicated that weight gain, specific growth rate, productive protein value and protein efficiency ratio increased, while feed conversion ratio decreased with increasing dietary lysine level up to 34.0 g/kg dry diet and then levelled off. Fish fed diet with 12.8 g/kg lysine had the lowest lysine content (58.6 g/kg dry matter) in muscle, while fish fed diet with 34.0 g/kg lysine had the highest value (61.6 g/kg dry matter; p < .05). Broken‐line analysis on the basis of weight gain showed that the optimal dietary lysine requirement for maximum growth of juvenile Pseudobagras ussuriensis is 33.5 g/kg dry diet (82.4 g/kg dietary protein). Quadratic regression analysis of protein efficiency ratio against dietary lysine levels indicated that the optimal dietary lysine requirement of juvenile Pseudobagras ussuriensis is 36.4 g/kg dry diet (89.5 g/kg dietary protein).  相似文献   

8.
An eight‐week feeding trial was conducted to evaluate the feed intake, growth, feed utilization, body composition and waste output of juvenile hybrid bream at different feeding frequencies (0.5, 1, 2, 3 or 4 meals/day). Fish (initial body weight of 10.6 ± 0.8 g) were fed to satiation at each feeding. The test diet contained 336 g/kg crude protein and 79 g/kg crude lipid. The weight gain significantly increased with increase in feeding frequency from 0.5 to 3 meals/day (p < 0.05) and afterwards did not change with feeding frequency from 3 to 4 meals/day (p > 0.05). The feed intake increased with increase in feeding frequency (p < 0.05). Fish fed at 3 meals/day exhibited the lowest feed conversion ratio and waste output of nitrogen and phosphorus, however, the highest nitrogen retention efficiency (p < 0.05). No significant differences were found in the phosphorus retention efficiency, the body composition of crude protein, ash and phosphorus among all the feeding frequencies (p > 0.05). The body lipid content increased, whereas the content of moisture decreased, with the increase in feeding frequency (p < 0.05). The present study reveals that the optimum feeding frequency is 3 meals/day for hybrid bream.  相似文献   

9.
The effect of replacing fish meal (FM) with meat and bone meal (MBM) in diets for juvenile Pseudobagrus ussuriensis was evaluated in a 90‐day feeding trial. Six isonitrogenous (crude protein, 430 g/kg) and isolipidic (crude lipid, 74 g/kg) diets were formulated to contain MBM to replace FM at 0 (S0), 200 (S20), 400 (S40), 600 (S60), 800 (S80) and 1000 g/kg (S100), respectively. The results showed that there was no significant difference in weight gain (WG) among fish fed S0, S20 and S40 diets. However, a significant reduction in WG occurred when 600, 800 and 1000 g/kg FM protein was replaced by MBM (p < .05). Similar trends were observed in specific growth rate and protein efficiency ratio. Apparent digestibility coefficients (ADC) of protein and dry matter of the diets S80 and S100 were significantly lower than those of the other diets. The ADC of phosphorus significantly reduced with the increase in dietary MBM level. Nitrogen and phosphorus excretion increased with the increasing dietary MBM level. Protease, lipase and amylase activities of the diets S80 and S100 were significantly lower than those of the other diets (p < .05). The results of this study showed that the optimum dietary MBM replacement level was 34.3% according to broken‐line model based on WG against dietary MBM replacement level.  相似文献   

10.
We assessed the effects of a fishmeal (FM)‐ and two soya‐based diets [without or with prebiotic (GroBiotic® ‐A; GBA) supplementation] on the production performance, non‐specific immunity, blood parameters and gut microbiota diversity of red drum, Sciaenops ocellatus. All diets were formulated to contain 450 g/kg crude protein (CP) and 120 g/kg lipid. A combination of soya bean meal and soya protein concentrate (SP) was used to replace 88% of the FM in the FM‐based diet (REF) originating the first soya‐based diet (SOY). The second soya‐based diet (SOY + GBA) was designed identically to SOY except for the supplementation of GBA (20 g/kg) substituting for wheat flour. After feeding the experimental diets to triplicate groups of 25 (~3.4 g/fish) and 90 (~4.1 g/fish) red drum juveniles for 9 (Trial I) and 16 weeks (Trial II), our results showed that (i) red drum was highly sensitive to the soya‐based diets in the first week of feeding; (ii) replacing 88% of FM with SP reduced the production performance of red drum without affecting intestinal micromorphology; (iii) whole‐blood leucocyte oxidative radical production was unaffected while lower haematocrit and higher plasma lysozyme activity were found in fish fed REF; (iv) plasma osmolality was unaffected while lower glucose and higher lactate levels were observed in fish fed SOY and SOY + GBA; (v) 16S rRNA gene‐based diversity of fish gut microbiota was affected both by SP and by GBA. This study expands the information on red drum responses to soya‐based diets and prebiotic supplementation.  相似文献   

11.
Six isoproteic diets were designated to evaluate the effects of dietary lipid levels (from 70 to 270 g/kg) on the growth performance, feed utilization, digestive tract enzyme activity and lipid deposition of juvenile Brachymystax lenok (average initial weight 0.54 ± 0.04 g). Each diet was fed to triplicate tanks (30 fish per tank) in an indoor closed recirculating system for 9 weeks. Final body weight and weight gain were highest in fish fed 190 g/kg diet and lowest in fish fed the 70 g/kg diet. Specific growth rate of fish fed with 190 g/kg diet was significantly higher than those fed with 70 and 270 g/kg diets (p < .05). Protein efficiency ratio of fish fed with 70 g/kg diet was significantly lower than the 110–230 g/kg treatments and was not significantly different from the 270 g/kg treatment. Fish fed with 270 g/kg diet had significantly higher hepatosomatic index and viscerosomatic index than those fed with 70–190 g/kg diets (p < .05). Intraperitoneal fat ratio and the whole‐body lipid content had a trend to increase with increase in dietary lipid level. Muscle crude lipid content increased up to 190 g/kg with increase in dietary lipid level. Lipid retention decreased with increase in dietary lipid level, while no significant differences in protein intake and retention levels were observed in fish among all treatments. Lipase activity of the mixture of pyloric caeca and foregut in fish fed 190 and 230 g/kg diets was significantly higher than those fed 70 and 110 g/kg diets. Midgut and hindgut lipase activities of fish were significantly higher than those fed the 190 and 230 g/kg diets. In conclusion, based on the second‐order polynomial model of WG and FCR, this study suggested that 173.8–195.0 g/kg dietary lipid levels were appropriated for B. lenok.  相似文献   

12.
A 60 days feeding trial was conducted to illustrate the effect of graded levels of protein on the growth and metabolic enzymes of grey mullet (Mugil cephalus L.) fingerlings reared in inland saline water (ISW). Six isoenergetic (16 MJ/kg) and isolipidic (60 g/kg) diets containing 240, 260, 280, 300, 320 and 340 g crude protein (CP)/kg diet were formulated and fed to triplicate. Weight gain %, specific growth rate, protein utilizing efficiency, feed efficiency and RNA:DNA ratio were significantly higher (p < .05) in 320 and 300 g CP/kg diets. Fish fed with 240 g CP/kg diet showed significantly higher (p < .05) feed intake, whole‐body lipid content, hepatosomatic index value and liver glycogen content. Transaminase enzymes and malate dehydrogenase activities were elevated in fish fed 340 g CP/kg diet. Protease activity increased with increasing dietary CP level, but amylase activities showed an inverse relationship. No significant (p > .05) variations were observed for lactate dehydrogenase, oxidative stress enzymes, blood parameters and serum osmolality among all the treatment groups, but red blood cell count increases with increasing dietary CP levels. Based on the results, feeding dietary protein level of 300 g CP/kg is economically viable for rearing of grey mullet in ISW.  相似文献   

13.
A 50‐day feeding trial was conducted to examine the effects of dietary protein and lipid levels on growth, feed utilization, body composition and swimming performance of giant croaker, Nibea japonica. Fish (initial body weight 44.6 g ind−1) were fed ten test diets which were formulated at 5 crude protein levels (360, 400, 440, 480 and 520 g kg−1) and 2 crude lipid levels (90 and 150 g kg−1). In addition, a raw fish diet (fillet of small yellow croaker) served as the reference. The weight gain (WG) increased, whereas the feed intake (FI) and feed conversion ratio (FCR) decreased, with increasing dietary protein level from 360 to 520 g kg−1. At the same dietary protein level, no significant difference was found in the WG between fish fed the diets containing 90 or 150 g kg−1 crude lipid. Fish fed the diet containing 480 g kg−1 crude protein and 90 g kg−1 crude lipid exhibited higher WG, nitrogen retention efficiency (NRE) and energy retention efficiency (ERE) but lower nitrogen wastes output (TNW). At the end of the feeding trial, the hepatosomatic index (HSI) and viscerosomatic index (VSI) decreased, whereas the body protein content increased, with increase in dietary protein level. The body lipid content was higher in fish fed at the 150 g kg−1 lipid level than in fish fed at the 90 g kg−1 lipid level. No significant difference was found in the maximum sustained swimming speed (MSS) between fish fed at different dietary protein and lipid levels. The WG, NRE, ERE and condition factor (CF) were higher, whereas the FI, FCR, HSI, VSI and TNW were lower, in fish fed the raw fish diet than in fish fed the diet containing 480 g kg−1 crude protein and 90 g kg−1 crude lipid. No significant difference was detected in the MSS between fish fed the raw fish diet and diet containing 480 g kg−1 crude protein and 90 g kg−1 crude lipid. The results of this study suggest that the suitable dietary crude protein and crude lipid levels are 480 g kg−1 and 90 g kg−1 for giant croaker reared in net pens.  相似文献   

14.
This study was carried out to evaluate the dietary available phosphorus (AP) requirement for crucian carp (Carassius auratus). Triplicate groups were fed diets containing five graded levels of AP in 15 recirculating tanks. After a 9‐week feeding experiment, weight gain (WG), specific growth rate (SGR), feed efficiency (FE) and whole‐body and vertebrae P contents were significantly increased as dietary AP increased from 1.1 to 7.6 g/kg (p < .05) and then levelled off. N and P retention was also significantly increased as dietary AP increased to 5.5 g/kg (p < .05). Condition factor, viscerosomatic index, hepatosomatic index, whole‐body moisture, muscle P content and plasma total cholesterol were not affected by dietary P levels (p > .05). Protein and ash contents of the whole body increased linearly as the dietary P level increased, but the lipid content, plasma alkaline phosphatase activities and triacylglycerol contents showed an inverse relationship. Based on WG, FE, whole‐body P content and vertebrae P content, the optimum requirement of dietary AP for crucian carp was estimated to be 8.3, 8.3, 8.0 and 7.8 g/Kg, respectively.  相似文献   

15.
To determine optimized dietary nutrient supply for common carp (Cyprinus carpio), nine isoenergetic diets were formulated according to a two‐factorial central composite design on digestible basis. Digestible protein contents (DP) in diets ranged from 208.8 to 251.2 g/kg, and digestible fat‐to‐digestible carbohydrate energy ratios (DEF/DEC) varied from 0.79 to 1.21. Carp were fed four times a day at a daily feeding rate of 2.5 g/kg body weight for 56 days. Optima of responses were determined by applying the standard least squares method according to response surface methodology. All diets resulted in excellent performance with feed conversion ratios lower than 1 and digestible protein efficiency ratios (PERdig) higher than 4.6. For most parameters, calculated extreme values were minimum points, except for FCR, retention efficiencies of digestible arginine (RetArgdig) and of digestible methionine (RetMetdig), being maximum points, and retention efficiencies of digestible isoleucine, digestible sulphuric amino acids and digestible lysine, being saddle points. Highest growth and feed utilization efficiency were graphically determined for a diet containing 208.8 g/kg DP/1.21 DEF/DEC. Body lipid was optically increased for 251.2 g/kg DP/0.79 DEF/DEC in comparison with 208.8 g/kg DP/1.21 DEF/DEC.  相似文献   

16.
A 90‐day feeding trial was conducted on milkfish, Chanos chanos with an initial mean body weight of 3.07 ± 0.17 g (mean ± standard error of mean). Six treatment diets were formulated to contain 0 g/kg (Diet 1), 150 g/kg (Diet 2), 25 g/kg (Diet 3), 300 g/kg (Diet 4), 350 g/kg (Diet 5) and 450 g/kg (Diet 6) distiller's dried grain with soluble (DDGS). All the dietary treatments were isonitrogenous (350 g/kg crude protein) and isolipidic (6% crude lipid). Result of the feeding trial indicated that growth rates, feed intake and feed efficiency were not significantly (p > .05) affected by inclusion levels of DDGS by up to 450 g/kg in the feed. Proximate body composition (crude protein, crude lipid, ash, fibre) in fish fed the dietary treatments were not significantly (p > .05) affected as well. The DDGS when used as a milkfish ingredient has a protein digestibility of 910 g/kg, fat disgetsibility of 850 g/kg, carbohydrate digestibility of 750 g/kg and a dry matter digestibility of 520 g/kg Results from the intestinal morphology displayed no apparent pathological changes in the digestive tract of fish fed all dietary treatments. These results indicate that DDGS can be efficiently utilized by milkfish by up to 450 g/kg without negatively affecting performance parameters and intestinal morphology.  相似文献   

17.
A feeding trial was conducted to evaluate the effect of nucleotides supplementation to low‐fish meal feed on growth and fatty acid composition of rainbow trout. Six isonitrogenous (42% crude protein) and isolipidic (18% crude lipid) diets were formulated containing fish meal and plant ingredients as main protein sources. The control diet was a basal diet without supplementation of nucleotides, and five experimental diets were prepared by supplementing one of the five different nucleotides in the form of 5′‐monophosphate (0.15%), that is inosine (IMP), adenosine (AMP), guanosine (GMP), uridine (UMP) and cytidine (CMP) onto basal diet. Two hundred forty juvenile rainbow trout with an initial average body weight 9.8 g were randomly distributed into twelve aquaria. After 15 weeks of feeding period, growth performance and feed utilization of rainbow trout were not significantly different among dietary treatments. Dietary GMP, UMP and CMP tended to accumulate crude lipid in the muscle and whole fish body. Moreover, dietary GMP, UMP and CMP significantly increased hepatic 18:3n‐3 and long‐chain homologue 18:4n‐3 and 20:4n‐3 contents. Hepatic 18:2n‐6 content showed also increase in fish fed GMP, UMP and CMP diets, but decreased in long‐chain homologue 20:3n‐6 and 20:4n‐6 contents. Decrease in 20:4n‐6, 20:5n‐3 and 22:6n‐3 contents was also found in the muscle of fish fed IMP, GMP and CMP diets. The present study clearly showed that there was no positive effect of dietary nucleotides on growth of fish, but dietary nucleotides particularly GMP, UMP and CMP altered polyunsaturated fatty acid composition of rainbow trout.  相似文献   

18.
An 8‐week feeding trial was conducted with extruded practical diets containing 320 g/kg of crude protein from plant‐based sources to determine the effects of L‐lysine on growth performances, muscle‐growth‐related gene (myoD, myogenine and myostatin) expression and haemato‐biochemical responses in juvenile genetically improved farmed tilapia (GIFT). Five isonitrogenous and isoenergetic diets were formulated to contain graded levels of lysine (14.3, 16, 17.5, 19 and 20.5 g/kg of diet). Each diet was randomly assigned to triplicate groups of 30 juvenile fish (5.2 ± 0.1 g), which were fed thrice a day (9:00, 13:00 and 17:00 hr). Maximum growth performances were observed in fish fed with lysine at 19 g/kg of diet. There was no significant (p > .05) effect on whole‐body composition and amino acids profile by dietary lysine supplementation. Significant (p < .05) changes were observed in relative expression of muscle‐growth‐related genes namely myoD and myogenine and in plasma metabolites by dietary lysine supplementation. In contrast, the relative expression of myostatin was not affected by dietary lysine supplementation. Broken‐line regression analysis and second‐order polynomial regression analysis of weight gain and N gain against dietary lysine levels showed that the dietary lysine requirement for juvenile GIFT tilapia was 18–18.3 g/kg of diet and 19.3–19.5 g/kg of diet, respectively.  相似文献   

19.
An 8‐week feeding trial was conducted to investigate the effects of dietary carbohydrate‐to‐lipid (CHO:L) ratios on growth, liver and muscle glycogen content, haematological indices, and liver and intestinal enzyme activity of juvenile grouper (Epinephelus coioides). Five isonitrogenous (496.0 g/kg protein) and isoenergetic (21.6 KJ/g gross energy) diets with varying CHO:L ratios of 0.65 (D1), 1.31 (D2), 2.33 (D3), 4.24 (D4) and 8.51 (D5), respectively, were fed to triplicate groups of 20 fish (average 10.02 ± 0.1 g) for 8 weeks. Results showed that the weight gain rate, specific growth rate and protein efficiency ratio (PER) of juvenile grouper increased first and then decreased with the increase in CHO:L ratio, reaching a maximum value in the D4 (CHO:L = 4.24) diet. The trend for the feed conversion ratio was opposite to the PER. Along with the diet CHO:L ratios, the apparent digestibility coefficients (ADC) of crude lipid and energy for the juvenile groupers decreased gradually, while the ADC of dry matter, liver and muscle glycogen level increased gradually. Total protein, triglycerides and cholesterol in serum were all maximized in the D4 diet and glucose in the D5 (CHO:L = 8.51) diet. Digestive enzyme activity in the intestine was significantly affected by dietary CHO:L ratio. Liver hexokinase, phosphofructokinase and glucose‐6‐phosphate dehydrogenase activity increased significantly as CHO:L ratio increased. Liver lysozyme and acid phosphatase activity in the groupers fed the D3 (CHO:L = 2.33) diet was significantly higher than that of other diets. Liver fructose‐1,6‐bisphosphatase and alkaline phosphatase activity reached a maximum value in the D4 diet and was significantly higher than that in the D1 diet. Taking the above results together, it can be concluded that an optimal dietary CHO:L ratio of 2.33 is suitable for grouper culture concerning growth performance and health.  相似文献   

20.
De‐oiled (<10 g/kg oil) carinata (Brassica carinata) meal is high (>400 g/kg) in protein, but its use in fish diets will likely be limited mainly by glucosinolates (GLS), sinapine and crude fibre. Two feeding experiments were conducted to determine the response of hybrid striped bass (Morone chrysops ♀ X M. saxatilis ♂, HSB) to inclusion of cold‐pressed carinata meal (CPCM) in diets. Cook extrusion reduced an average of 44% and 57% of GLS and sinapine concentrations in diets, respectively. In experiment 1, diets containing 0.71–2.71 μmoles of GLS and 0.034–0.181 mg of sinapine/g did not significantly (p > .05) reduce feed consumption, utilization or growth, resulting in similar concentrations of thyroxines and consequently no effect on deiodinase enzymes. In experiment 2, there was a significantly reduced (p < .05) feed consumption in fish fed diets containing 5.58–9.52 μmoles of GLS and 0.54–0.75 mg of sinapine/g, resulting in HSB exhibiting lethargic swimming and feeding behaviours, and consequently poor feed utilization and growth. Cook extrusion reduced about half of GLS and sinapine, and HSB tolerated ≤2.71 μmoles of GLS and ≤0.31 mg of sinapine/g of diet without affecting feed consumption and utilization, growth and thyroid metabolism.  相似文献   

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