Effect Of Food Restriction And Starvation On Compensatory Growth In Juvenile Trachinotus Ovatus

In this paper,there are two aquaculture experiments.The Trachinotus ovatus which initial weight is 50.14±2.84 g/tail and body length is 11.49±0.40 cm were studied,to find out the influence of type and way of compensatory growth by food restriction and starvation,and study the influence of regulation mechanism,such as nutritional content,energy metabolism,digestive enzymes activity,serum hormones levels,and so on.The results are as follows: 1.Compensatory growth response following period of food restriction in juvenile Trachinotus ovatus The experimental fish were divided into 5 groups,namely 4 treatment groups: R1 fasting 12 d,R2 feeding 20%,R3 feeding 40%,R4 feeding 60%,and all groups were recovered satiation feeding 28 d after diet restriction 12d;The control group R5 continued satiation feeding 40 d.The results showes that:(1)The R1 occurred partially-compensatory growth,and the rest groups occurred completely-compensatory growth.(2)Each group increasing the feeding rate was the main way to achieve compensatory growth,and increasing the feed conversion ratio was an auxiliary way.(3)Restricting food period,water and crude ash content of muscle was increased,and crude protein and crude fat reduced to varying degrees.(4)Restricting food period,the order of decomposition of hepatopancreas energy metabolism was liver glycogen,fatty and protein.(5)Restricting food period,the digestive enzyme activity of organization had a trend of lowering after first increased,and the protease had minimal influence,the amylase was the maximum.(6)The serum cortisol level was the most sensitive,and regulate body when the body affected by starvation;The serum growth hormone increased fast in restricting food period and decreased slowly in recovery period;The triiodothyronine has decreased in restricting food period,and rised rapidly to higher than normal level,and it was the main mechanism for the occurrence of compensatory growth.2.Compensatory growth response following period of starvation in juvenile Trachinotus ovatus The experimental fish were divided into 4 groups,3 treatment groups : T1 satiation feeding 36 d after hunger 4d,T2 satiation feeding 32 d after hunger 8d,T3 satiation feeding 28 d after hunger 12d;The control group T4 continued satiation feeding 40 d.The results showes that:(1)The T1 occurred over-compensatory growth,the T2 occurred completely-compensatory growth,and the T3 occurred partially-compensatory growth.(2)Each group achieved compensatory growth by increasing both the feeding rate and the feed conversion ratio.(3)Water and crude ash content of muscle increased with starvation time extended,crude protein and crude fat decreased with that.(4)Starvation period,the liver glycogen,fatty and protein decreased to varying degrees,and the protein was slower than others.(5)The digestive enzyme activity of organization had a trend of lowering after first increased,and the protease was more stable.(6)The serum cortisol level increased with starvation time extended,and return prompt to normal level after recovery feeding;The serum growth hormone increased in starvation period and decreased slowly in recovery feeding period,and their speed related with the extent of starvation;The triiodothyronine has decreased in starvation period,and rised rapidly to higher than normal level and maintained at that level for some time.The triiodothyronine had a synergy with growth hormone to regulate compensatory growth.