Dietary effect on skeletal development of Atlantic salmon (Salmo salar)

The main aim of this thesis was to study the effect of dietary treatments on the skeleton of Atlantic salmon. This experiment was conducted prior to moving the fish to the seawater phase. The starting weight of the salmon in this experiment was 20g.\nFour diets were produced and used in this study. The diets were formulated with varying levels of marine protein and oils, vegetable protein and oils and minerals.\nThe diets were designed Marine diet produced from a 1995 recipe with alterations with the mineral phosphorus (M), Marine diet with low mineral concentration (M-LM), Standard diet with vegetable protein and oils referred to as the Control diet(C) and lastly the control diet with Vitamin K (CK+).\nThis study was conducted at a NOFIMA research station, Sundalsøra, Norway. These four diets (C, CK+, M, M-LM) were triplicate, were 12 tanks in total. After 16 weeks of experimentation, ten fish per tank were randomly selected. During the sampling, the fish had an average weight of 73g. Calorimetric analysis of the skin were taken and biometric traits and score data were also measured and recorded.\nFurthermore, morphological traits /skeletal deformities were also diagnosed or studied using the semi-digital X-ray mammography. X -ray pictures were examined for vertebra fusions, (fusions), compressions, hypo mineralized, and loss of intervertebral spaces.\nThe mechanical properties of the vertebral column in the (anterior /ANT) and the portion between the posterior end of the dorsal fin and the gut (NQC/Norwegian quality cut). The instrument used was the TA-XT2 analyser. Parameters collected used from the mechanical analyses were compression force(N), Area (total work N*s) and thickness (mm). \nAlso, the concentration of minerals in the skeleton was determined. Minerals accounted for were calcium (Ca), phosphorus (P), magnesium (Mg), manganese (Mn).\nBased on the results of this experiment, the total work (N*sec) required to compress the vertebrae to 50% of total thickness was the most representative parameter. The NQC region/section had the highest thickness, Area and compression force in all the treatments. The NQC had the largest stiffness and strength. In terms of individual treatments, CK+ had the highest Area, Compression force and thickness amongst all the dietary treatments in the anterior section of the skeleton.\nThe control diet (C) had the highest Area, Compression force in the NQC region but not thickness.\nIn terms of Mineral Analysis, Marine diet had the highest concentration of Ca, Mg, P, Zn.\nVisual score of the skin showed that there was significant difference between treatments. This significant difference was seen in scale loss, red-green, a*, yellow- blue, b*\nBiometric traits and score data showed that heart weight, CSI, visceral fat was had significant difference between dietary treatments.