Study On The Optimum Protein And Lipid Requirement And Supplementation With Animal And Plant Ingredient In Feeds For Golden Pompano Trachinotus Ovatus

This paper reported the results of experiments in which the optimum protein andlipid requirement, replacing fish meal with cost-effective protein ingredients andsupplementation with poultry by-product meal and selenoyeast in diet formulation forgolden pompano （Trachinotus ovatus）. This study consisted of three experiments:（1） Toobserve that growth, feed utilization and body composition of juvenile golden pompanofed the diets with different protein and lipid levels.（2） Effect of replacing dietary fishmeal with poultry by-product meal and soybean meal on growth, feed utilization andbody composition of golden pompano.（3） Effect of supplementation with dietarypoultry by product meal and selenoyeast on replacement of fish meal with soybean mealin diets for juvenile golden pompano.The experimental design and process was as follows:1. In the experiment1, a feeding trial was conducted to determine the optimaldietary protein and lipid levels for juvenile golden pompano Trachinotus ovatus rearedin net pens. Ten test diets were formulated at five protein (330,370,410,450or490g·kg^-1crude protein) and two lipid (65or125g·kg^-1crude lipid) levels. Goldenpompano fingerlings (initial body weight4.7g·fish^-1) were fed the test diets for8wks.Weight gain （WG）, specific growth rate （SGR）, feed conversion ratio （FCR）, nitrogenretention efficiency （NRE）, energy retention efficiency （ERE）, condition factor （CF）,hepatosomatic index （HSI）, protein content of whole body and total nitrogen wasteoutput （TNW） were dependent on both dietary protein and lipid levels （P <0.05）. Feedintake （FI） and viscersomatic index （VSI） were dependent on dietary protein level,while lipid content of whole body was dependent on lipid level （P <0.05）. Weight gainand SGR increased with increasing dietary protein level （at the same lipid level） butdecreased with increasing lipid level （at the same protein level）. Fish fed the dietscontaining460to500g·kg^-1crude protein had higher WG, but lower FCR, relative tothose of fish fed the diets containing330to420g·kg^-1crude protein （P <0.05）. Energyretention efficiency increased with increasing dietary protein level, while NREincreased with increasing dietary protein level from330to410g·kg^-1, and then decreased thereafter. Increasing dietary lipid level resulted in the decrease in ERE andNRE. Results of this study suggest increasing dietary lipid level could not induceprotein sparing action in golden pompano, and460to500g·kg^-1crude protein and65g·kg^-1crude lipid could satisfy dietary protein and lipid requirements of juvenile goldenpompano reared in net pens.2. In the experiment2, two feeding trials were conducted to examine the effect ofreplacing dietary fish meal with poultry by-product meal （PBM） and soybean meal（SBM） on growth, feed utilization and body composition of juvenile golden pompanoTrachinotus ovatus reared in net pens. In the trial I, a control diet （C） was formulated tocontain350g·kg^-1fish meal, and40,60,80and100%of the fish meal in diet C wasreplaced with PBM on equal protein basis in the remainder diets. In the trial II,40and60%of the fish meal in diet C was replaced by either PBM or SBM, respectively. WhenPBM was used as fish meal substitute, weight gain （WG）, specific growth rate （SGR）,nitrogen retention efficiency （NRE） and energy retention efficiency （ERE） decreased,while feed conversion ratio （FCR） and nitrogen waste output （TNW） increased, withreducing fish meal level from350to210g·kg^-1. No significant differences were foundin hepatosomatic index （HSI）, viscersomatic index （VSI）, proximate composition （crudeprotein, crude lipid and ash） and energy content of whole body, and phosphorus wasteoutput （TPW） between fish fed diet C and diets containing PBM as fish meal substitute.At the same fish meal replacement level, WG, SGR, NRE and ERE was higher, whileFCR and TNW lower, in fish fed the diets with PBM as fish meal substitute than in fishfed the diets with SBM as fish meal substitute. Results of this study indicate thatreducing dietary fish meal from350to210g·kg^-1, whatever with PBM or SBM as fishmeal substitute, could result in the decrease in growth rate and feed utilizationefficiency of golden pompano. Compared with SBM, PBM is a favorable dietary proteinsource for golden pompano.3. In the experiment3, three feeding trials were conducted to examine the effect ofthe supplementation with dietary poultry by product meal （PBM） and selenoyeast onreplacement of fish meal with soybean meal in diets for juvenile golden pompano. Inthe trial I, two dietary PBM was formulated to contain100g·kg^-1（Diet C1, S11&S12）and170g·kg^-1（Diet C2, S21&S22）. At each dietary PBM,40%（Diet S11&S21） and60%（Diet S12&S22） of the fish meal in diet C was replaced with soybean meal（SBM）. In the trial II, when dietary fish meal was40%replaced with SBM （Diet S11&S21）, S11Se and S21Se were added1g·kg^-1selenoyeast, respectively. In the trial III,when dietary fish meal was60%replaced with SBM （Diet S12&S22）, S12Se and S22Se were added1g·kg^-1selenoyeast, respectively. At two dietary PBM, WG, SGRand NRE was higher, while FI, FCR, TNW and TPW lower, in fish fed diet C1than infish fed diet C2. At each dietary PBM, when SBM was used as fish meal substitute,WG,SGR, NRE, ERE and TPW were lower, while FI, FCR and TNW were higher. Whendietary fish meal was40%replaced with SBM, WG, SGR, NRE and PRE was higher,while FI and FCR lower, in fish fed diets S21and S21Se than in fish fed diet S11. Whendietary fish meal was60%replaced with SBM, WG and SGR was higher, while FI andFCR lower, in fish fed diets S22than in fish fed diet S12. Whatever dietary fish mealwas40%or60%replaced with SBM, supplementation with selenoyeast could resultin the increase in WG and SGR, and decrease in FI and FCR of golden pompano.Results of this study indicate that at same dietary fish meal and protein level, dietaryPBM can significantly affect growth performance and feed utilization efficiency ofgolden pompano. High dietary PBM or supplementation with selenoyeast havebeneficial to replace fish meal with SBM. Improving dietary PBM level to170g·kg^-1,and add1g·kg^-1selenoyeast, dietary fish meal level could reduce to140g·kg^-1, whenSBM was used as fish meal substitute.