Powdered Milk — An Alternative to Animal Protein in Rainbow Trout

The chemical composition of two types of milk powder - whole and skim milk was studied. The richest in protein is skimmed milk powder. The possibility of using skimmed milk powder in compound feed for rainbow trout has been established. Compound feed formulations have been developed with partial replacement of fish meal with skimmed milk powder. The modes of extrusion were selected for compound feeds containing a heat-sensitive component - milk powder. It was found that the optimal percentage of skimmed milk powder is 10%. It was found that compound feed containing 10% skimmed milk was used 1.8 times more effectively in the fish organism compared to the control. The coefficient of protein utilization when feeding with compound feed with 10% input of skimmed milk powder is 1.1 times higher, and the accumulation of substances in the body of rainbow trout is 40% more intensive. The nutrient content in the compound feed containing 10% skimmed milk per kilogram of rainbow trout growth is 1.4 times higher than in the control. To increase the efficiency of rainbow trout feeding, a compound feed has been developed containing 10% skimmed milk powder instead of fish meal. Modes of compound feed extrusion were selected: the optimal temperature range is 90-100 0С, the range of humidity values is 28-30%. A regression equation was obtained that adequately describes the change in the content of essential amino acids with an increase in the extrusion temperature in the composition of a compound feed containing 10% skimmed milk powder, empirical coefficients of the regression equation were selected.