Introduction
In fish farming, optimizing feeding for optimal growth is crucial. Feeding strategies for Atlantic salmon are influenced by factors like day length and temperature. However, drawing definitive conclusions from feeding studies can be challenging. Understanding the best feeding practices for post-smolt Atlantic salmon in sea cages is limited. Our study aimed to determine the most effective feeding regimes for salmon health and performance. We hypothesized that varied feeding frequencies of overfeeding across seasons would impact fish growth, welfare, resource utilization, and feed waste. Our approach aimed to strike a balance between underfeeding, hindering growth, and excessive overfeeding, leading to waste, to establish best practices in Atlantic salmon feeding.
Material and Methods
The 41-week feeding trial at LetSea’s R&D sea facility in Northern Norway involved large smolts (±700g) . Fish were distributed across 12 sea cages (125 m3), each with 150 fish. Conducted in triplicate, all cages received conventional industrial feed. Four study groups followed different feeding strategies: FS1 (2 meals/day + 0% overfeeding), FS2 (1 meal/day + 0% overfeeding), FS3 (1 meal/day + 10% overfeeding), and a control group (CF) with 2 meals/day and 10% overfeeding. Post-trial, fish were weighed, and welfare scoring conducted. Parameters including fat content, color, melanin, gaping, and texture were compared among groups. Muscle histology and product quality samples were collected, with fat and color analysis using Near-infrared spectroscopy and digital Salmofan.
Results
One-way ANOVA showed significant differences (p-value = 0.007) in the weights mid-experiment (mid-weights); however, we observed no significant differences in the end weights. Significant differences were also observed in the SGR values among the experimental groups and control. We did not observe any corresponding trend concerning temperature and oxygen changes in the feeding responses. Results of the effects on welfare and fillet quality will be presented at the Conference. In summary, this study suggests that feeding regimes can be used to obtain a healthy Atlantic salmon of good quality and desirable growth during a typical commercial production cycle. The study shows that a chosen feeding strategy can impact several growth and quality parameters in Atlantic salmon.