Dissertation
Dissertation > Agricultural Sciences > Aquaculture, fisheries > Aquaculture technology > A variety of fish farming

Study of Nutritional Requirement of Jade Perch(Scortum Barcoo)

Author SongLiPing
Tutor AnLiGuo
School Shandong Normal University
Course Zoology
Keywords Perch Nutritional needs B vitamins Non - nutritional additives
CLC S965
Type PhD thesis
Year 2009
Downloads 390
Quotes 5
Download Dissertation

Jade perch(Scortum barcoo) is a highly valuable tropical freshwater fish with very few bones and a good taste. Jade perch that efficiently utilizes commercial feed and grows rapidly has become an increasingly important commercial species in China. Because of its fast growth, efficient feed conversion, and high market value, aquaculture of the fish plays an important role in the economy of China. The dietary requirements of protein, lipid, carbonhydrate, riboflavin, pyridoxine, pantothenic acid and folic acid and the effects of calcium (Ca), phosphorus, probiotics, xylooligosaccharides and phytase enzyme on growth and physiology state of juvenile jade perch were conducted in indoor cylindrical fiberglass tanks (400L ) or net cages (60cm×60cm×120cm). Results of the present study are presented as follows.The dietary requirements of protein, lipid and carbonhydrate for juvenile jade perch1. To conduct the dietary protein requirement of jade perch juveniles, fishmeal was as protein source, a 60-day feeding trial with five diets was conducted to investigate the effect of dietary protein levels (25.1% 30.2%, 36.1%, 40.2 and 45.6%) on the growth performance, feed utilization, digestive enzyme activities, whole body and muscle composition of jade perch juveniles. Five groups with three replicates of juvenile were reared in net cage (60cm×60cm×120cm). The final body weight of 25.1% group was lower than that of 36.1%、40.2% and 45.6% group (P<0.05). Fish fed diet with 25.1% dietary protein level had significantly lower daily gain (DG) and specific growth rate (SGR) than those groups with high dietary protein level (P<0.05) . The values of DG and SGR of jade perch showed increasing trend with increasing dietary protein level from 25.1%to 36.1%, then showed decreasing trend from 36.1% to 45.6% (P<0.05). The values of feed conversion ratio (FCR) and protein efficiency ratio (PER) for fish fed 25.1% dietary protein were significantly higher than other groups (P<0.05). The values of FCR showed decreasing trend with increasing dietary protein level from 25.1%to 36.1%, then showed increasing trend from 36.1% to 45.6% (P<0.05). The values of PER exhibited decreasing trend with increasing dietary protein level from 25.1%to 36.1% (P>0.05), then decrease from 36.1% to 45.6%, there was significant difference between groups (P<0.05). Jade perch fed 36.1% dietary protein exihibited higher values of final body weight, DG, SGR, PER and lower value of FCR than other groups (P<0.05). There were no significant difference in condition factor among groups (P>0.05). A linear increase (P<0.05) in protease activity was observed due to feeding increased dietary protein level. An inverse relationship was observed between intestinal amylase activity of jade perch and the dietary protein level. The protein content of whole body and muscle tended to increase, but crude lipid content tended to decrease with increasing dietary protein level(P<0.05). No differences between groups were found for crude ash and dry matter of whole body and muscle (P>0.05). Using the relative weight gain as the indicator, the broken-line regression analysis indicated that the optimum dietary protein requirement of juvenile jade perch were 35.98%.2. To conduct the dietary lipid requirement of jade perch juveniles, diets containing 36.3% crude protein supplemented with increasing lipid levels (5.7%, 8.4%, 10.9%, and 13.1% of the dry matter) were used to feed triplicate groups of 30 fish for 60 d. At the end of the experiment, more than 95% fish survived well from all diet groups (P > 0.05). Measurements on the final body weight , daily gain (DG) and specific growth rate (SGR) indicated that fish fed with diets of 10.9% and 13.1% lipids exhibited higher growth performance (P < 0.05), while these values between fish fed with 10.9% and 13.1% lipid diets were not significantly different. Lowest growth performance was observed for fish fed with the lowest lipid level, the 5.7% lipid diet (P < 0.05). The values of FCR were also significantly (P < 0.05) affected by dietary lipid levels and tended to decrease with increasing lipid levels. Fish fed with the 5.7% diets showed the highest FCR values, while fish in the 13.1% feeding group yielded the lowest FCR values. Evaluations for the feed conversion ratio (FCR) and the protein efficiency ratio (PER) indicated that fish fed with 10.9% and 13.1% lipid diets utilized their feed and dietary proteins more efficiently (P < 0.05). The lipid and dry matter content of whole body tended to increase, but crude protein content tended to decrease with increasing dietary lipid level (P<0.05). Jade perch fed 13.1% dietary lipid exhibited higher lipid content of whole body than the fish fed diets with 5.7% and 8.4% dietary lipid (P<0.05). Jade perch fed diet with 10.9% dietary lipid exhibited higher lipid content of whole body than the fish fed with 5.7% dietary lipid (P<0.05). Fish fed 13.1% dietary lipid exihibited lower protein content of whole body than the fish fed diets with 5.7% and 8.4% dietary lipid (P<0.05). Fish fed diet with 10.9% dietary lipid exhibited lower protein content of whole body than the fish fed with 5.7% dietary lipid (P<0.05). Crude ash contents were similar from whole fish in all treatment groups (P>0.05). Jade perch fed diet with 10.9% and 13.1% dietary lipid exhibited higher dry matter content of whole body than the fish fed with 5.7% dietary lipid (P<0.05).Lipid contents increased in muscles from fish fed with higher lipid diets, and reached the highest in fish fed diets with the 10.9% and 13.1% lipid (P<0.05). On the other hand, protein contents decreased in muscles from fish fed with increasing dietary lipids (P < 0.05), and reached the lowest in those fed diet with the 13.1% lipid. The amounts of muscle dry matter elevated from fish fed with the higher dietary lipids (P<0.05) and reached the highest amounts in the juveniles fed with the 10.9% diet. There were no significant difference in condition factor among groups. As dietary lipid level increased, viscerosomatic index (VSI) and hepatosomatic index (HSI) increased dramatically and the 13.1% group had the highest values. Activities of hepatic glucose-6-phosphate dehydrogenase (G6PDH) and malic enzyme (ME) were reduced with increasing lipid level, but activities of phosphogluconate dehydrogenase (PGD) did not change among groups. Jade perch fed diet with 5.7% dietary lipid exhibited higher activities of G6PDH and ME than fish fed diet with 13.1% dietary lipid (P<0.05). In conclusion, high dietary lipid levels above 10.9% produced little practical benefit because of higher fat accretion in jade perch.3. To conduct the dietary carbohydrate requirement of jade perch juveniles, cornstarch was as carbohydrate source, a 60-day feeding trial with five diets was conducted to investigate the effect of dietary carbohydrate levels (25.4%、29.6%、33.2%、37.3% and 41.5% ) on the growth performance, feed utilization, heopatic metabolic enzymes, plasma biochemical indices ,whole body and muscle composition of jade perch juveniles . The apparent digestibility coefficient (ADC) of protein and lipid decreased with increasing dietary carbohydrate level , and reached the lowest in those fed diet with the 41.5% carbohydrate level (P < 0.05). Jade perch fed diet with 25.4% and 29.6% dietary carbohydrate level exhibited higher ADC of lipid than the other groups (P<0.05). ADC of carbohydrate were similar in 25.4%, 29.6%, 33.2% and 37.3% groups (P > 0.05), and the 41.5% group had the lowest values (P<0.05). The final body weight, daily gain (DG) and specific growth rate (SGR) increased at a level of dietary carbohydrate not more than 33.2%, and decreased at a higher dietary carbohydrate leve1(from 33.2% to 41.5%) (P < 0.05). The values of feed efficiency ratio (FER) and protein efficiency ratio (PER) tended to increase with increasing dietary carbohydrate level (P<0.05). Jade perch fed diets with 33.2%、37.3% and 41.5% carbohydrate level exhibited higher FER and PER values than 25.4% and 29.6% groups (P<0.05). There was no significant difference in condition factor among groups (P>0.05). As dietary carbohydrate level increased, the values of viscerosomatic index (VSI) and hepatosomatic index (HSI) increased and fish fed diet with 37.3% and 41.5% carbohydrate level exhibited higher HSI values than those with 25.4% carbohydrate level (P<0.05). Activities of hepatic pyruvate kinase and glucokinase increased with increasing lipid level, but activities of hepatic hexokinase decreased. Jade perch fed 41.5% carbohydrate diet exihibited higher activities of hepatic pyruvate kinase and glucokinase, and lower activities of hepatic hexokinase than the fish fed with 25.4% dietary carbohydrate (P<0.05). Fish fed 25.4% carbohydrate diet exhibited lower plasma glucose content than the fish fed with 37.3% and 41.5% carbohydrate diets (P<0.05). The plasma triglycerides and cholesterol content, the protein, ash and dry matter content of whole body and muscle were no remarkable differences among groups (P>0.05). Jade perch fed diet with 37.3% carbohydrate level exhibited higher plasma glucan content and lipid content of whole body and musle than the fish fed with 25.4% carbohydrate diet (P<0.05). In conclusion, the results suggested that the optimal dietary carbohydrate level for jade perch was 33.2-37.3%.The dietary requirements of riboflavin, pantothenic acid , pyridoxine and folic acid for juvenile jade perch and the effect of dietary calcium (Ca) and phosphorus (P) on growth performance and physiology state of juvenile jade perch.4. A study was conducted to investigate the dietary requirement of riboflavin for juvenile jade perch, and to characterize riboflavin deficiency signs. Six isoenergetic and isonitrogenous purified diets (0.60、2.83、5.21、7.37、9.86 and 20.26 mg riboflavin /kg dry diet) were prepared using casein and gelatin as protein sources. Fish fed the basal diet (0.60 mg/kg) exhibited lower final body weight, daily gain (DG), specific growth rate (SGR), feed efficiency ratio (FER) and protein efficiency ratio (PER) than the fish fed diets supplemented with riboflavin (P<0.05). Fish fed diet supplemented with 2.83 mg /kg riboflavin exhibited lower final body weight, DG, SGR, FER and PER than other groups supplemented with riboflavin (5.21、7.37、9.86 and 20.26 mg/kg) (P<0.05), and no significant differences were observed among the other dietary treatments (P>0.05). Hepatic D-amino acid oxidase activity (D-AAO) was low in the riboflavin-deficient fish and increased in a dose-response manner with maximum activity being observed in fish fed the 5.21mg riboflavin/kg diet (P<0.05), and then leveled off (P>0.05). The riboflavin concentrations in the livers of fish fed basal diet was the lowest (P<0.05), and increased with increasing riboflavin up to 5.21 mg/kg (P<0.05), and then leveled off (P>0.05). Fish fed the riboflavin-free diet performed poorly in terms of growth parameters and exhibited signs of riboflavin deficiency such as caudal fin erosion, loss of normal body color and photophobia. No deficiency signs were observed in fish fed the riboflavin-supplemented diets. Using SGR, D-AAO and hepatic riboflavin concentrations as the indicator, the broken-line regression analysis indicated that the optimum dietary riboflavin requirements of juvenile jade perch were 5.73, 6.85 and 6.64 mg/kg respectively.5. A study was conducted to investigate the dietary requirement of pantothenic acid for juvenile jade perch, and to characterize pantothenic acid deficiency signs. Six isoenergetic and isonitrogenous purified diets (0.05、5.45、11.20、22.25、45.07 and 84.86 mg pantothenic acid /kg dry diet) were prepared using casein and gelatin as the main protein sources. Fish fed the basal diet (0.05 mg/kg) exhibited lower final body weight, specific growth rate (SGR), feed efficiency ratio (FER) and protein efficiency ratio (PER) than the fish fed diets supplemented with pantothenic acid (P<0.05). Fish fed diet supplemented with 5.45 mg/kg pantothenic acid exhibited lower final body weight, SGR, FER and PER than other groups supplemented with pantothenic acid (22.25、45.07 and 84.86 mg/kg) (P<0.05), and no significant differences were observed among the other dietary treatments (11.20、22.25、45.07 and 84.86) (P>0.05). Hemoglobin and hepatic lipid were significantly lower in fish fed the basal diet than those of fish fed supplemented diets (P<0.05), but no significant differences in hemoglobin and hepatic lipid were observed among the pantothenic acid-supplemented dietary groups (P>0.05). Hepatic lipid concentration was highest in the pantothenic acid-deficient fish than those of other dietary groups (P<0.05), and no significant differences were observed among the other dietary treatments (P>0.05). Hepatic total patothenate concentration (TP) was lowest in the pantothenic acid-deficient fish than those of other dietary groups, and no significant differences were observed among the other dietary treatments(11.20、22.25、45.07 and 84.86 mg/kg) (P>0.05) .Hepatic free pantothenate concentrations(FP) between fish fed Diet 1 and Diet 2 were similar, and were significantly lower than those of fish fed diets supplemented with 22.25 mg/kg pantothenic acid (P<0.05) , then leveled off (P>0.05). Hepatic bound pantothenate concentration (BP) was lowest in the pantothenic acid-deficient fish than those of other dietary groups (P<0.05), and no significant differences were observed among the other dietary treatments (P>0.05). Fish fed the pantothenic acid-free diet performed poorly in terms of growth parameters and exhibited signs of pantothenic acid deficiency such as gill pale, lethargy, dark body color and skin hemorrhages. Using SGR and BP as the indicator, the broken-line regression analysis indicated that the optimum dietary pantothenic acid requirements of juvenile jade perch were 12.40 and 13.47 mg/kg respectively.6. A study was conducted to investigate the dietary requirement of pyridoxine for juvenile jade perch, and to characterize pyridoxine deficiency signs. Six isoenergetic and isonitrogenous purified diet(s0.18、1.46、3.14、6.71、12.67 and 26.25 mg pyridoxine /kg dry diet) were prepared using casein and gelatin as the main protein sources. Fish fed the basal diet (0.18 mg/kg) exhibited lower final body weight, specific growth rate (SGR), feed efficiency ratio (FER) and protein efficiency ratio (PER) than the fish fed diets supplemented with pyridoxine (P<0.05). Fish fed diet supplemented with 1.46 mg/kg pyridoxine exhibited lower final body weight, SGR, FER and PER than other groups supplemented with pyridoxine (3.14、6.71、12.67 and 26.25 mg/kg) (P<0.05), and no significant differences were observed among the other dietary treatments(P>0.05). Hepatic aspartate aminotransferase (AST)and alanine aminotransferase (ALT) activity were low in the pyridoxine-deficient fish, and no significant differences were observed among the other dietary treatments (3.14、6.71、12.67 and 26.25 mg/kg) (P<0.05). The pyridoxine (PN) and pyridoxal 5’-phsophate (PLP) concentrations in the livers were the lowest in fish fed the basal diet (P<0.05), and increased with increasing dietary pyridoxine up to 6.71 mg/kg (P<0.05), and then leveled off (P>0.05). Fish fed the pyridoxine-free diet performed poorly in terms of growth parameters and exhibited signs of pyridoxine deficiency such as pale body color, erratic swimming and loosening of scales. No deficiency signs were observed in fish fed the pyridoxine-supplemented diets. Using SGR, AST, ALT, PN and PLP as the indicator, the broken-line regression analysis indicated that the optimum dietary pyridoxine requirements of juvenile jade perch were 2.67、3.85、4.04、4.91 and 5.17 mg/kg respectively.7. A study was conducted to investigate the dietary requirement of folic acid for juvenile jade perch, and to characterize folic acid deficiency signs. Seven isoenergetic and isonitrogenous purified diets (0.11、0.11、0.58、1.07、2.20、4.52 and 9.15 mg folic acid /kg dry diet) were prepared using casein and gelatin as the main protein sources. Fish fed the basal diet (0.11 mg/kg) exhibited lower final body weight, specific growth rate (SGR), feed efficiency ratio (FER) and protein efficiency ratio (PER) than the fish fed diets supplemented with folic acid (P<0.05). Fish fed diet supplemented with 0.58 mg/kg folic acid exhibited lower final body weight, FER and PER than other groups supplemented with folic acid (1.07、2.20、4.52 and 9.15 mg/kg) (P<0.05). Fish fed diet supplemented with 0.58 mg/kg folic acid exhibited lower SGR than other groups supplemented with folic acid (2.20、4.52 and 9.15 mg/kg) (P<0.05), but similar with group supplemented with folic acid (1.07 mg/kg) (P>0.05). Final body weight, SGR, FER and PER were no significant different among the folic acid-supplemented dietary groups (1.07、2.20、4.52 and 9.15 mg/kg) (P>0.05). Final body weight, SGR, FER, PER, numbers of erythrocytes (RBC) and hepatic folic acid concentrations were no significant difference between the fish fed the basal diet with or without succinylsulfathiazole. Fish fed diet supplemented with 0.58 mg/kg folic acid exhibited lower RBC and hepatic folic acid concentrations than other groups supplemented with folic acid (1.07、2.20、4.52 and 9.15 mg/kg) (P<0.05), and no significant differences were observed among the other dietary treatments (P>0.05). Fish fed the folic acid-free diet performed poorly in terms of growth parameters and exhibited signs of folic acid deficiency such as pale body color, congestion in fins and lethargy. No deficiency signs were observed in fish fed the folic acid-supplemented diets. Using SGR, RBC and hepatic folic acid concentrations as the indicator, the broken-line regression analysis indicated that the optimum dietary folic acid requirements of juvenile jade perch were 1.03, 1.20 and 1.24 mg/kg respectively. 8. A study was conducted to investigate the effects of dietary calcium (Ca) and phosphorus (P) on juvenile jade perch, and to characterize P deficiency signs. Six isoenergetic and isonitrogenous purified diets (Diet 1: 0.0% Ca, 0.0% P; Diet 2: 0.5% Ca, 0.0% P; Diet 3: 0.0% Ca, 0.6% P; Diet 4: 0.5% Ca, 0.6% P; Diet 5: 1.0% Ca, 0.6i% P; Diet 6: 1.5% Ca, 0.6% P) were prepared using casein and gelatin as the main protein sources, Ca-lactate and NaH2PO4·2H2O as the Ca, P source , respectively. Fish fed diets without P supplement(Diet 1 and Diet 2)showed reduced final weight, special growth rate(SGR) and mineral (Ca and P) deposition in vertebrae, and an increase in feed conversion rate (FCR), whole body and muscle lipid content than fish fed diets with P supplement (P<0.05). When P was not supplemented, 0.5% Ca supplement had no significant effect on final weight, SGR , FCR, whole body and muscle composition, ash content and mineral (Ca, and P) deposition in vertebrae (P>0.05). When diets were supplemented with 0.6% P, Ca supplement from 0.0% to 1.5% had no significant effect on final weight, SGR, whole body composition, muscle composition (moisture, crude protein and ash), vertebrae composition (ash, P and Ca-P ratio ) (P>0.05) . Excess Ca supplement (1.5%) had a negative effect on vertebrae Ca deposition (P<0.05). Fish fed diets with P supplement(Diet 3- Diet 6) showed an decrease in whole body and muscle lipid content, an increase in ash content and mineral (Ca, and P) deposition in vertebrae (P<0.05) . Ca and P supplement had no significant effect on Ca-P ratio ranged from1.78 to 1.82 in vertebrae (P>0.05). Fish fed the P-free diet exhibited lower plasma phosphorus and plasma alkaline phosphatase (ALP) activity than other groups supplemented with 0.6% P (P<0.05), and no significant differences were observed among the other dietary treatments though supplemented with different Ca level (P>0.05). If growth performance and vertebrae mineralization are taken into account, 0.5% Ca supplement might be optimum when diet was supplemented with 0.6% P. Non-nutritive additive for jade perch9. The Lactobacillus sp. and Bacillus sp. were added to jade perch basal diets as the probiotics in three forms: 0.1% lyophilized Lactobacillus sp. (L), 0.1% lyophilized Bacillus sp. (B) and their mix, and used to investigate the effect of probiotics on growth performance, feed utilization, digestive enzyme activities and intestinal microflora. Fish fed the diets supplemented with probiotics showed significantly better results of final body weight, daily gain (DG), specific growth rate (SGR), feed efficiency ratio (FER) and protein efficiency ratio (PER) than those with the basal diet (control). Final body weight, DG, SGR, FER and PER were no significant difference between the fish fed the diets supplemented with Lactobacillus sp. and with Bacillus sp., but was lower than the mix group. Mean digestive enzyme activities of all probiotics groups were significantly higher than the control group (P<0.05). Fish fed diet supplemented with Bacillus sp. exihibited higher protease activities than fish fed diet supplemented with Lactobacillus sp. (P<0.05). Fish fed diet supplemented with Lactobacillus sp. and Bacillus sp. exhibited higher amylase and lipase activities than fish fed diet supplemented with Lactobacillus sp. (P<0.05). As for amylase and lipase, assays showed no difference between groups supplemented with probiotics(P>0.05). Supplementation with probiotics had no influence on intestinal aerobic bacterial counts (P>0.05), and affected the composition of intestinal microflora with a tendency of Aeromonas, Enterobacteriaceae, Vibrio, Flavobacterium decreasing and Alcaligence, Bacillus increasing as compared with the contol (P<0.05). Supplementation with probiotics had no influence on intestinal Corynebacterium, Acinetobacter, and Staphylococcus (P>0.05). Fish fed the diets supplemented with probiotics showed significantly better results of phagocytic percentage (PP), phagocytic index (PI) and alkaline phosphatase (AKP) than those with the basal diet (control). In conclusion, it showed that probiotics highly increased the growth performances, feed utilization, digestive enzyme activities and immunity function and improve intestinal microbial balance. Furthermore, different probiotics forms indicated different performances and the mix produced the best results.10. A 60-day feeding trial was conducted to investigate the effect of dietary xylooligo saccharides (XOS) on the growth performance, feed utilization, digestive enzyme activities, bacteria of intestinal and immune of jade perch juveniles. The basal diet was used as control, the trial diets were designed with 4 added levels of XOS which were mixed with the basal diet. The added levels of XOS were 0.06‰, 0.12‰、0.18‰and 0.24‰respectively. The results showed that Jade perch fed the control diet showed lower final body weight, daily gain (DG), specific growth rate (SGR), feed efficiency ratio (FER) , protein efficiency ratio (PER) , protease, amylase and lipase activities than fish fed diets supplemented with 0.12‰、0.18‰and 0.24‰XOS (P<0.05), and no significant differences compared with fish fed diet supplemented with 0.06‰XOS (P>0.05). Fish fed diet supplemented with 0.12‰XOS exhibited better final body weight, DG, SGR, FER and PER than other groups. There were no significant difference in protease and lipase activities among groups supplemented with XOS (P>0.05). Jade perch fed the control diet showed higher glucose, triglycerides and cholesterol in serum than fish fed diets supplemented with 0.18‰and 0.24‰XOS, and no significant difference among groups supplemented with XOS (P>0.05). The XOS additive could significantly (P<0.05) decrease the number of total bacteria counts, no significant difference among groups supplemented with XOS (P>0.05). Supplementation with XOS affected the composition of intestinal microflora with a tendency of Aeromonas and Enterobacteriaceae decreasing and Alcaligence and Bacillus increasing as compared with the control (P<0.05). Supplementation with probiotics had no influence on intestinal Corynebacterium, Acinetobacter and Staphylococcus (P > 0.05). Supplementation with XOS had no influence on intestinal Corynebacterium, Acinetobacter, and Staphylococcus (P>0.05). Jade perch fed the control diet showed lower phagocytic percentage (PP), phagocytic index (PI) , lysozyme (LSZ) and alkaline phosphatase (AKP) than fish fed diets supplemented with XOS, and no significant difference among groups supplemented with XOS (P>0.05). The present results suggested that the diet added XOS can improve growth, feed utilization, digestive enzyme activities and immune of jade perch juveniles, the optimum dietary XOS requirements of juvenile jade perch were 0.12‰.11. A 60-day feeding study was conducted to investigate the effect of dietary phytase on the growth performance, feed utilization and digestive enzyme of jade perch juveniles. The basal diet designed with fish meal as protein source was used as control, the trial diets were designed with partially replacing fish meal with soybean meal as replacing fish meal group, replacing fish meal group with 0.02% phytase as phytase group. The results showed that jade perch fed the control diet showed higher final body weight, daily gain (DG), specific growth rate (SGR), feed efficiency ratio (FER) , protein efficiency ratio (PER) , protease and lipase activities than replacing fish meal group (P<0.05), and no significant differences compared with phytase group (P>0.05). Fish fed the replacing fish meal group diet showed lower final body weight, DG, SGR, FER, PER, protease and lipase activities than phytase group (P<0.05). Fish fed basal and phytase groups diet exhibited better apparent digestibility coefficient (ADC) of protein, lipid, dry matter, total phosphorous and calcium than replacing fish meal group (P<0.05). Retention of nitrogen in replacing fish meal group was significantly lower than the control group (P<0.05), and load of nitrogen in replacing fish meal group was significantly higher than phytase group. No differences between control and phytase groups were found for retention and load of nitrogen (P>0.05). Fish fed phytase group diet exhibited higher retention and lower load of phosphorous than other groups (P<0.05)。Load of phosphorus in control group was significantly higher than the other groups (P<0.05). Supplementation with soybean meal and phytase had no influence on retention of calcium (P>0.05) and affected load of calcium with a decreasing tendency (P<0.05).

Related Dissertations
More Dissertations