Dietary inclusion of a partially defatted black soldier fly(Hermetia illucens)larva meal in low fishmeal-based diets for rainbow trout(Oncorhynchus mykiss)

Background:Recent investigations highlighted that Hermetia illucens(BSF)larva meal can be a valuable alternative protein source for aquafeed production.In this study,in substitution of fishmeal,we used increasing inclusion levels of a partially defatted BSF larva meal in low fishmeal-based diets for rainbow trout(Oncorhynchus mykiss Walbaum)and we evaluated the related implications in terms of growth performance,physical characteristics,proximate and fatty acid(FA)compositions of the fillets,gut and liver histology,and diet digestibility.In a 131-day trial,576 fish(100.1±9.29 g)were randomly allotted to 24 tanks(24 fish/tank,4 replicates/treatment).Six experimental diets were produced to have partial replacement of fishmeal(0,10%,20%,30%,40%and 50%)by increasing levels of BSF meal(0%[BSF0],3%[BSF3],6%[BSF6],9%[BSF9],12%[BSF12]and 15%[BSF15]on as fed basis,respectively).Results:No differences were observed among the treatments for all the considered growth performance parameters.The viscero and hepato-somatic indexes showed significant differences among the treatments,with the highest values observed in the BSF15 group.No differences were recorded in terms of fillet’s physical characteristics,dry matter(DM),crude protein(CP)and ether extract(EE)contents.Total saturated and monounsaturated FA increased,while polyunsaturated FA(particularly n-3 FA)decreased while increasing the HI meal inclusion in the diet.Histopathology of liver and gut was not affected,whereas,in posterior gut,villi were higher in BSF6 and BSF9 compared to BSF3 fish.The apparent digestibility of DM,CP,EE and gross energy did not vary among the treatments.Conclusions:These results suggest that a partially defatted BSF meal could be included up to 15%in low fishmeal-based diets for rainbow trout with no adverse effects on growth performance,fillet’s physical characteristics,gut and liver health,and diet digestibility.On the contrary,the fillet FA composition worsened while increasing the level of BSF meal in the diet.

A Study on the Meat and Bone Meal or Poultry By-product Meal as Protein Substitutes of Fishmeal in Concentrated Diets for Paralichthys olivaceus

A study was conducted to evaluate the effects of meat and bone meal （MBM） and poultry by-product meal （PBM） as the replacement of fishmeal in the diets on the growth performance, survival and apparent digestibility coefficient （ADC） of Japanese flounder （Paralichthys olivaceus）. The experimental diets included 0%, 20%, 40%, 60% and 80% MBM or PBM replacement of total fishmeal respectively. All diets were iso-nitrogenous and isocaloric. The results showed that there are no significant differences （P 〉0.05） in growth performance among the treatments fed with 0% -60% MBM replacement of fishmeal, while the percent weight gain （WG, % ）, body length gain （BLG, % ） and ADC significantly decrease when fishmeal is replaced by 80% MBM. The result showed also that there are no significant differences （P 〉0.05） in growth performance and ADC among all treatments fed with the diets with 0% -80% replacements of fishmeal with PBM.