Effect of Varied Dietary Protein Levels on Resource Allocation to Somatic Mass and Defense Structures in Red Tilapia (Oreochromis niloticus x O. mossambicus)

Abstract

Isocaloric diets containing 15%, 25%, 35%, and 45% crude protein (CP) were prepared and fed with to red tilapia fry for three months to ascertain the effects of varying protein levels on resource allocation to somatic mass and structural defense. Morphometric parameters measured included dorsal fin length, anal fin length and dorsal spine height. Tests for correlation of these parameters relative to total length and body weight were performed and confidence intervals were computed. Results revealed that patterns of resource allocation change with decrease in dietary protein. The fish under nutrient stress were not only thin and small but also produced longer dorsal fins compared to the less stressed individuals. Titus, given limited resources, the fish tend to allocate more available resources to defense structure development to increase their fitness, at the expense of somatic growth. This study also supports research findings regarding 35% CP as the diet promoting growth that is most advantageous for aquaculture.