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| Effects of Dietary Exogenous Enzymes on Growth and Feed Utilization in Juvenile Turbot (Scophthalmus maximus) |
| LU Yuan-yuan,WU Li-xin,JIANG Zhi-qiang,CHEN Wei,ZHANG Xue |
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Abstract A feeding trial was conducted to investigate the effects of dietary exogenous enzymes (phytase , non‐starch polysaccharide enzymes and the mixture of the two enzymes) on growth ,body composition , food digestibility and utilization in juvenile turbot (Scophthalmus maximus) .A total of 144 juvenile turbot with an average body weight of (20 .53 ± 0 .10) g were randomly divided into 4 groups and fed a basal diet (as a control group) ,and the basal diet supplemented with phytase at a rate of 200 mg/kg diet ,non‐starch polysaccharide enzymes at a rate of 100mg/kg diet and the mixture of the two enzymes for 42 days at water temperature of 14 .0—18 .5 ℃ with triplication .Results showed that the exogenous enzymes supplementa‐tion led to significant improvement of specific growth rate compared to the control group (P<0 .05) ,the best grow th (increased by 16 .30% ) in the fish fed the diet containing mixture enzymes ,without signifi‐cant differences in food intake ,food conversion ratio ,protein efficiency ratio and survival rate (P>0 .05) . The moisture ,and levels of crude fat ,ash and energy of the juvenile turbot were not affected significantly by the exogenous enzyme supplementation (P>0 .05) .The crude protein level ,however ,was increased (P> 0 .05) ,the maximum in the fish fed the diet containing non‐starch polysaccharide enzymes (P<0 .05) .There were significantly higher apparent digestibility of feed dry matter ,crude protein ,phosphor‐us and energy in the juveniles fed the diet containing non‐starch polysaccharide enzymes and mixture en‐zymes than in the juveniles in the control group (P< 0 .05) .The fish fed the diet containing phytase showed significantly higher apparent digestibility of crude protein (P<0 .05) ,and higher apparent digesti‐bility of feed dry matter ,phosphorus and energy without significant differences ( P> 0 .05) .Exogenous enzyme supplementation resulted in significant improvement of retention of nitrogen and phosphorus ( P<0 .05) ,and in significant decrease in nitrogen load (P<0 .05) .Phosphorus load was not affected signifi‐cantly by dietary phytase and non‐starch polysaccharide enzymes (P>0 .05) ,even though the phosphorus load showed the downward trend .
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Received: 25 November 2014
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